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HomeMy WebLinkAboutAPA1668p ; ) ~FINAL ENVIRONMENTAL IMPACT STATEMENT Prudhoe Bay Oil Field Waterflood Project Prudhoe Bay, North Slope Borough Alaska OCTOBER 1980 Prepared by: U.S. Army Corps of Engineers, Alaska District P.O. Box 7002, Anchorage, AK 99510. Information Contact: (907)752-3861 (Ben Kutscheid) Cooperating Agencies: National Marine Fisheries Service U.S. Environmental Protection Agency U.S. Fish and Wildlife Service Technical Assistance Provided by: Dames & Moore, Anchorage Abstract: The proposed action is issuance of permits under authority of Section 10, Rivers and Harbors Act of 1899, and Section 404, Clean Water Act to the Sohio Alaska Petroleum Co. and the ARCO Oil and Gas Co. to construct and operate a project to recover an additional billion barrels of oil from the currently producing reservoir. This would make a significant contribution to society•s energy needs. Other effects of the proposed project relate to water quality, water circulation, fish and other biota in the Arctic Ocean, wetlands, wildlife, and subsistence resources. Other alternatives are analyzed that have greater or lesser -effects. R~F AL~SK~Last Date to Accept Comments: 17 NOVEMBER 1980 TN a12 ·t\1 f 5&1 vo\. l Copy I TABLE OF CONTENTS VOLUME r List of Tables .. List of Figures . SUMMARY ;INTRODUCTION. ., AFFECTED ENVIRONMENT. ALTERNATIVES AND ENVIRONMENTAL EFFECTS. No Action. . . . . . . . . . . . . . . De 1 ay. . . . . . . . . . . . . . . . . Alternatives at the National Level ..... . Alternatives for Enhanced Oil Recovery (EOR) at Prudhoe Bay . . . . . . . . . . . . . . . . PAGE X xii . s -1 . s -2 . s -4 s -4 . s -5 . s -5 s -6 . s -6 Alternative Ways to Accomplish Waterflooding . The Applicant•s Proposed Project ....•.. Other Alternatives to Accomplish Waterflood • 0 s -7 1.1 1.2 at Prudhoe Bay . . . . • . . . • . . . . . . . . . . The Environmentally Preferred Alternative. CHAPTER 1.0 INTRODUCTION EIS PURPOSE AND HISTORY • . . . STATUS OF THE PROPOSED ACTION . 1.3 PURPOSE AND NEED FOR THE PROPOSED ACTION. 1.4 1.5 2.1 2.2 STATUS OF LICENSES, PERMITS AND APPROVALS . FORMAT. • • • • • 0 • " • • • • • • • • • CHAPTER 2o0 ALTERNATIVES 'INTRODUCTION. NO ACTION AND DELAY ALTERNATIVE NO:ACTION o • o •••• o •• o • DELAY • • • • 0 • • II • • • • • • Cover Photo Courtesy Sohio Alaska Petroleum Co. i . s -8 . s -11 . 1 - 1 • 1 - 2 • 1 - 2 1 - 5 . 1 - 5 . 2 - 1 • 2 - 5 2 - 5 • 2 - 8 PAGE 2.3 ALTERNATIVES AT THE NATIONAL LEVEL. . . . . . . . 2 -10 2.4 ALTERNATIVES TO ENHANCE OIL RECOVERY. . 2 -11 GAS INJECTION . . . . . . . . . . . . . . . . . . . 2 -11 POLYMER FLOODING. . . . . . . . . . . . 2 -11 CARBON DIOXIDE INJECTION. . . . . . . . . .2:-11 CAUSTIC FLOODING. . . . . . . . . . . . . 2 -12 MICELLAR SOLUTION (CHEMICAL) FLOODING 2 -12 STEAM INJECTION . . . . . . . . . . . . . . 2 -13 IN-SITU COMBUSTION (FIREFLOOD). . . . . 2 -13 >· . ~[ 2.5 ALTERNATIVES TO ACCOMPLISH WATERFLOODING. . . . . 2 -13 ~·! ,. I \.'. THE APPLICANT'S PROPOSED PROJECT. . . . . . . . . 2 -17 F. General. . . . . . . . . . . . . . . . 2 -17 Causeway Extension and Modifications . . . . 2 -20 Description . . . . . . . . . . . . 2 -20 Environmental Impact. . . . . . . . . . . 2 -24 Seawater Intake and Treating Plant . . . . . . . . 2 -28 Description . . . . . . . 2 -28 Environmental Impact. . . . . . 2 -34 Outfall Pipelines. . . . . . 2 -37 Description . . . . . . 2 -37 Environmental Impact. . . . . . . . . 2 -38 Dredging . . . . . . . . . . . . . 2 -41 Description . . . . . . . t . 2 -41 Environmental Impact. 2 -41 Low-Pressure Pipeline. . . . 2 -41 Description . . . . . . 2 -41 Environmental Impact. . . . . . 2 -43 Inject ion Plants . . . . . . 2 -44 Description . . . . . . 2 -44 Environmental Impact. 2 -44 High-Pressure Pipelines. . . . . . . 2 -46 Description . . . . . . . . t-46 Environmental Impact. . . . . 2 -46 Injection Site Facilities. . . 2 -46 Description . . . . . . . . . . . 2 -46 Environmental Impact. . . . 2 -47 Fuel and Power Systems . . . 2 -47 Description . . . . . . 2 -47 Environmental Impact. . 2 -50 System Freeze Protection . . 2 -50 Description . . . . . . . . . . . . . . 2 -50 Environmental Impact. . 0 . . . 2 -51 Air Emissions. 0 . . . 2 -52 Solid Waste. . . . . . . . . . 0 . 2 -52 - ii u---·----l PAGE Schedules, Construction Method, and Transportation •. 2 -54 Gravel Use . . ' . . . . . . . . . . . . 2 -56 Description ...•.. 0 o •••••• 0 2 -56 Environmental Impact. . . . . . . . . 2 -56 Labor, Supplies, and Services. . . . . . .... 2 -59 Project Abandonment. . . . . . . ...... o •• 2 -61 ALTERNATIVES OTHER THAN THE PROPOSED PROJECT. • 2 -61 Causeway A lter\nat i ves. . . . . . . . . 2 -61 Alternati~e B -Gravel Island . • . . . . . . 2 -66 Alternative C -Dredged Channel . . 2 -67 Alternative Breaching Schemes. . . . . . . . . . . 2 -71 Just ifi cab on and Benefits. . . . • • . 2 -71 Alternative Breach Designs •........... 2 -75 Alternati~e Breach Locations ...•....... 2 -75 Alternative Intake Screen Designs and Impacts ..... 2 77 Seawater Treating Plant. • . • . . . . . . • . . • 2 -78 Clarification and Filtration. . . . . . . 2-78 Bioci des. · . . . . . . . 2 -82 Coagulant . . . . . . . . . . . . . . . .• 2 -82 Deaeration .•........••...•.... 2 -83 Outfall Line Operation ....•......•.• 2-83 Treating Plant Location . . . • . . . 2 -83 Outfall Pipelines. . . . . . • . .......•. 2 -83 Marine Life Return Line . . .. 2 -83 Main Outfall Line . . . . • • . 2-84 Dredging Alternatives. • . . . . • • . . . . 2 -84 Dredging Methods .............•..• 2 -84 Disposal Areas. . . . . • . ......••• 2 84 Low-Pressure Pipeline Routing •............ 2 -85 Low-Pressure and High-Pressure Pipeline Construction 2 -88 Injection Plants . . . . . . . . ........ 2 -89 Fuel and Power. Systems • . • .•....•... 2 -90 Pipeline Freeze Protection . . • ...••... 2 -90 Freeze Protection of Injection Wells and Well Lines. 2-91 Road and Pad Construct ion. . . . . o • 2 -91 Gravel Sources ...••.. 0 • • • • • • • • • 2 -92 Labor, Supp 1 i es, and Services. . . . . 2 -92 Project Abandonment. • . . . . . . • . . . . . 2 -93 2.6 MITIGATIVE MEASURES .•. FISH GUIDANCE MEASURES. . . . . . •... LOW-PRESSURE PIPELINE: EMERGENCY DISCHARGE . DRAINAGE READJUSTMENTS. . . • . . . RESTORATION OF GRAVEL REMOVAL AREAS . . .. SITING TO AVOID WETLANDS .••... PROTECTION FROM ICE OVERRIDE ....... . iii 2 -93 2 -93 . • • • • • 2 -94 . . . . . 2 -94 2 -94 • • 2 -94 2 -95 I I PAGE PROCEDURAL MEASURES . . . . . . . o o . . o . . . . . o . . 2 -95 MARINE LIFE RETURN LINE . . • . • . . . . . . . . . 2 -· 95 2.7 THE ENVIRONMENTALLY PREFERRED PLAN. CHAPTER 3.0 AFFECTED ENVIRONMENT 3.1 INTRODUCTION ....• 3.2 PREHISTORY/HISTORY. . . . . . . . . 3o3 LAND USE ..... . LAND STATUS . . •• LAND USE PLANNING . 3.4 GEOLOGY AND SOILS . 3.5 3.6 GEOLOGY . . . . . . SEISMOLOGY ..... SUBSIDENCE ..•.. MINERAL RESOURCES . PHYSIOGRAPHY ...•. SOILS . . • . . . . . VEGETATION. o • • • • • Cl • • GENERAL DESCRIPTION . . . . . . • . . . . . • . . . VEGETATION MAPPING/HABITAT EVALUATION .•. VEGETATION RESOURCE VALUE AND SENSITIVITY . WILDLIFE. BIRDS • . MAMMALS . Caribou. • • Arctic Fox . Polar Bear • • • • Cl 0 • • • • • • 0 • • • • • 0 • • • • • • • • 3.7 WETLANDS .. o ... WETLAND VALUES. Food Chain Production. o o •••••• Habitat for Land and Aquatic Species . Hydro 1 ogy and Water Qua 1 i ty. . • • Subsistence and Recreational Use .• iv 2 -95 . 3 - 1 . 3 - 2 • 3 - 4 . 3 - 6 . 3 -10 3 -12 . 3 -14 3 -15 • 3 -15 . 3 -16 . 3 -16 . 3 -19 3 -20 . 3 -21 3 -22 . 3 -22 . 3 -23 • 3 -23 3 -27 • 3 -28 • 3 -29 3 -29 . 3 -30 . 3 -31 . 3 -31 . 3 -32 3 -32 . 3 -33 3.8 3.9 .-.-~....,-.,...-~~~~"::"'·-~--, .. -_--~---··---··-.---~------~----------·--.-·---------------~----~-~--.---------· ---. -· -------·--------------------- PHYSICAL AND CHEMICAL OCEANOGRArHY. . . . . . . . . . . . PAGE . 3 -33 I CURRENTS/CIRCULATION ........ ~ . WAVE CLIMATE. . . . . . . . ...• . . . . . . . . 3 -34 . . • • . . . 3 -35 STORM SURGES AND TIDES. . . . . . • . .• COASTAL EROSION AND BARRIER ISLAND MIGRATION. SEDIMENTS AND SEDIMENT TRANSPORT PATHWAYS • . . . . • 3 -36 . . 3 -37 . . . . • 3 -39 WATER QUALITY . o • • • • • • • o • • • 0 • • • • • 3 -39 ICE . . . . . . . . . . 3 -44 MARINE BIOLOGY. . . . . ..... . . . . . . • • • • • 3 -49 GENERAL ECOLOGY . . . . . . • . . . . . . • . . . • . • 3 -49 PRIMARY PRODUCERS. . . . • . . ·:. . • . . . • .• 3-50 ZOOPLANKTON . . . . . • . . . , . . . . • • . • 3 -50 BENTHOS . . . . . . . . . . . . . . . i • • • • • • • • • • • 3 -51 FISH...... . ....... ·'· . . . . . . 3-52 MARINE BIRDS. . . . . . . . . . • . . ....... 3 -56 MARINE MAMMALS........ . .;. . . • . • 3-56 3o10 FRESHWATER RESOURCES. • 3 -57 PHYSICAL ASPECTS. . . • . . . . . . . . . . . . . • . . .. 3 -57 BIOLOGICAL ASPECTS. . . . . . . . . . . . . • . . . . . . 3 -58 WATER AVAILABILITY AND USE. . . . . . ...•.•..... 3 -60 3oll GROUNDWATER RESOURCES •..• 3.12 METEOROLOGY AND AIR QUALITY . . . • • 3 -60 3 -62 METEOROLOGY . AIR QUALITY . . . . . . . . . . . . . . . . . 3 -62 Cl • • • • • • • • • • • • • • 3 -66 3.13 SOUND . o . 3.14 SOCIOECONOMIC CONDITIONS. NORTH SLOPE SOCIOCULTURAL CHARACTERISTICS . Subsistence ..... . Political Development. POPULATION AND EMPLOYMENT o North Slope. . . . o • • • • • • •• • Statewide. . 0 • • • • • • • • • • • • v 3 -66 . . . . . 3 -70 . . 3 -73 3 -73 . 3 -76 0 •• 3 -77 3 -77 3 -82 PUBLIC FINANCE. . . North S 1 o pe . Statewide. . . PAGE • 3 -82 • . 3 -82 • • 3 -84 3.15 THE FUTURE WITHOUT THE PROPOSED PROJECT . 3 -84 • • 3 -86 4.1 FUTURE ACTIONS ......... . Prudhoe Continued Production .. 3 -92 Sales Gas Conditioning Plant and Alaska Highway Natural Gas Pipeline. . . . . . . . 3-93 Kuparuk Field Development. . . . . . . • . 3 -93 Point Thomson and Offshore Development . • 3 -94 Duck Island/Offshore . • . . . . . . . .••• 3 -95 Gwydyr Bay and Stump Is 1 and. . • • . . . . • . . . • . 3 -95 Development of NPR-A and WODNWR. . . . . • . . . . 3 -96 Future Oil and Gas Lease Sales .... o ••••••• 3 -96 Exploration by Arctic Slope Regional Corporation ... 3 -97 Canadian Beaufort Sea Development. . . . . . . . 3 -97 Interrelationship of Arctic Development Nodes. . . 3 -97 FUTURE ENVIRONMENTAL AND SOCIAL PROFILES. . . • • • • 3 -98 Wet 1 and s • • • • • • . • • • • • • • • • •• 3 -98 Net Primary Productivity (Terrestrial) . Marine Area .. o ••••••••••• Waterbirds . . •.•.•.•.. • • • • . 3 -99 Marine Mammals ....... . Caribou ...•.......•.. Water Quality and Availability . . •.. Aesthetics .....•.....•.. Traditional Inupi at Culture .. Wilderness Value ...•....•.. CHAPTER 4.0 ENVIRONMENTAL CONSEQUENCES EVALUATION OF PROPOSED PROJECT .. . . . • • 3 -99 . .. 3 -99 . . 3 -100 . 3 -100 . 3 -101 . . . 3 -101 . • . . . 3 -101 . . . . 3 -102 . . . 4 - 1 PROJECT BENEFITS. . . . . . . . . . . . . . . . . . 4 - 1 UNAVOIDABLE ADVERSE IMPACTS . . . . . . • . 4 - 1 SHORT-TERM USE VERSUS LONG-TERM PRODUCTIVITY ........ 4-3 IRREVERSIBLE AND IRRETRIEVABLE COMMITMENTS OF RESOURCES . . 4 - 4 CUMULATIVE IMPACTS. . •.•...•..•...•..... 4 - 4 Terrestrial and Wetland Habitat. Waterbirds . . . . . . ... Caribou .........•....•. Grave 1 . . . . . . . . . . . . . . • vi • 4 -7 • 4 - 8 • • • • 4 - 8 0 • • • 4 - 9 PAGE Marine Habitat . . . . . . . . . . . . . . . ... 4 - 9 Air and Water Quality. . ...•......... ' .. 4 -10 North Slope Sociocultural -Effects. . .. 4 -11 Government Policy. . • . . . . . . . . . 4-12 Summary. . . . . . . . . . . . . . . Cl • • • • 4 -12 4.2 COMPARISON OF IMPACTS • LAND USE. . . . . . . . . . . . . : . . 4 -12 4 -13 Construction Impacts .....•........... 4 -13 Alternative A (Proposed by Applicant) • . .. 4-13 Alternatives. . . . . . . . ... 4 -16 Operation Impacts. . ..•.• 4 -16 GEOLOGY AND SOILS . • . • • • • • i. • 4 -17 Construction Impacts ...••• Gravel Sources and Needs. Rehabilitation Measures . Earthwork . . . • . . . . . . . . . . . . . 4 -17 • ,. • 4 -17 4 -18 • 4 -20 Operational Impacts ....... . . . • • • . • • 4 -20 Ponding and Blockage of Shallow Groundwater Flow .... . Heave and Settlement. . .. . . .. 4 -20 •• 4 -21 . 4 -21 Aggrading Offshore Permafrost • Subsidence from Oil Withdrawal. Seismological Activity .. • • • • • • 4 -21 . • • . • 4 -22 VEGETATION AND TERRESTRIAL WILDLIFE . Construction Impacts ...• Alternative A (Proposed Alternative Designs and Operation Impacts ..... . WETLANDS. Alternative A (Proposed Alternative Designs and . . . . . . . by Applicant) . Configurations. by Applicant) . Configurations. 4 -22 • • • 4 -22 . • 4 -22 . . • 4 -27 • • • • • 4 -28 • 4 -28 • . . 4 -31 • 4 -31 Construction and Operation Impacts . . . . . . . . . . 4 -31 Alternative A (Proposed by Applicant) . . . . . 4 -31 Other Alternatives. . . . . . . . . .... 4 -34 PHYSICAL AND CHEMICAL OCEANOGRAPHY. . . . . . . Construction Impacts .....•.•..•. Alternative A (Proposed by Applicant) . Alternative B (Gravel Island) .... vii 4 -34 4 -34 • • 4 -35 . . . . 4 -43 n•m--~ Alternative C Accidents . . Operation Impacts. (Dredged Channel) .. o • PAGE • • • • • 4 -44 4 -44 • 0 • • 4 -44 Alternative A Alternative B Alternative C Accidents . (Proposed by Applicant) (Gravel Island) ... o •• (Dredged Channel) . 4 -44 • • 0 • 4 -52 0 • 4 -52 • 4 -52 MARINE BIOLOGY ..... Construction Impacts ........ o •• Alternative A (Proposed by Applicant) . Alternative B (Gravel Island) ...•. Alternative C (Dredged Channel) .... Operation Impacts .•........•.. Alternative A (Proposed by Applicant) . . .. 4 -54 . •• 4 -54 . • 4 -54 • •• 4 -63 • 4 -64 . 4 -64 . 4 -65 0 4 -74 Alternative B (Gravel Island) . . .•.. Alternative C (Dredged Channel) 4 -75 Alternative Intake Design ..•..•.. Accidents . . 4 -76 0 •• 4 -77 FRESHWATER RESOURCES. Construction Impacts .... Alternative A (Proposed Alternative Designs and Operation Impacts ..... . Alternative A (Proposed Alternative Designs and GROUNDWATER RESOURCES . . . . . . . . . . . . by Applicant) . Configurations. by Applicant) . Configurations. Construction and Operation Impacts . METEOROLOGY AND AIR QUALITY o 4 -77 4 -77 • 4 -77 • • • • • 4 -79 . 4 -79 • . •• 4 -79 •• 4 -80 . 4 -80 • 4 -80 Construction Impacts . . .•... • 4 -81 4 -81 4 -82 . .• 4 -82 Operation Impacts. . . . . •.. SOUND . • Emissions . . . . . . . .... . Air Quality Review -PSD. . .. . Air Quality Review -NAAQS. Alternatives .. Construction Impacts . Operation Impacts ..... . Impact Assessment .. viii • 4 -82 . 4 -82 • • 4 -84 • 4 -86 ••• 4 -86 4 -86 • • •• 4 -87 SOCIOECONOMIC EFFECTS . . . . . . . . Construction Impacts . . ..•. Population and Employment . Public Finance ...... . PAGE • 4 -89 4 -89 • •• 4 -89 4 -90 Sociocultural Conditions. Archaeological Features .. . . . . . . . . 4 -91 Navigation ....... . Operation Impacts ...... . Population and Employment . Public Finance ..... . Sociocultural Conditions ... . CHAPTER 5.0 POTENTIAL MONITORING PROGRAMS AND PERMIT CONSTRAINTS • 4 -91 4 -91 4 -91 . • • • 4 -91 • 4 -91 • • • • 4 -92 5.1 PROGRAMS RELATING TO PROJECT PERFORMANCE AND ENGINEERING .• 5 - 2 5.2 MONITORING FOR PERMIT COMPLIANCE ...... . 5.3 MONITORIN~ OF ACCIDENTS AND SUBSIDENCE .. 5.4 POSSIBLE PERMIT CONSTRAINTS ....... . • • • • 0 5 - 3 5 - 4 . 5 -15 CHAPTER 6.0 LIST OF PREPARERS AND REVIEWERS CHAPTER 7.0 PUBLIC INVOLVEMENT CHAPTER 8.0 REFERENCES CHAPTER 9.0 GLOSSARY CHAPTER 10.0 INDEX ix TABLE 1.3-1 1.4-1 2.1-1 2.2-1 2.5-1 2.5-2 2.5-3 2.5-4 2.5-5 2.5-6 2.5-7 2.5-8 3.8-1 3.10-1 3.10-2 3.11-1 3.12-1 3.12-2 3.13-1 • LIST OF TABLES VOLUME I Effect of Waterflood on Sadlerochit Production. Status of Major Licenses, Permits, and Policy Compliance .... o ••••• Comparative Impacts of Alternatives Waterflood Catch-Up Injection Rates Typical System Chemical Usage (Estimated Average) Characterization of Main Outfall Pipeline Effluent .. Prudhoe Bay Unit Waterflood Project Estimated Air Emissions Summary Table Estimated Gravel Requirement Summary Prudhoe Bay Unit Waterflood Project . Existing Gravel Sources in the Prudhoe Bay Area . Comparison of Alternative Intake Configurations . Comparison of Alternatives for Waste Treatment Disposal .... Comparison of Low-Pressure Pipeline Route Alternatives .....•...... Average Annual Ice Cycle Within the Shorefast Ice Area, Central Beaufort Sea Coast, Alaska. Selected Life History Information for Fish Utilizing the Sagavanirktok and Kuparuk Rivers. Prudhoe Bay Development Area Water Availability . Groundwater Quality at a Prudhoe Bay Well . Climatic Summary, Barter Island, Alaska • Existing Air Quality, Prudhoe Bay, Alaska PAGE 1 - 4 1 - 6 2 -2 2 -9 2 -33 2 -35 2 -53 2 -57 2 -58 2 -68 2 -79 2 -87 3 -47 3 -59 3 -61 3 -63 3 -64 3 -69 Background Ambient Sound Levels in the Project Vicinity •.. 0 ••••••••• • 3 -72 X TABLE 3.14-1 3.14-2 3.14-3 3.14-4 3.15-1 4.2-1 4.2-2 4.2-3 4.2-4 4.2-5 4.2-6 4.2-7 5.0-1 Population of North Slope Borough, July 1978. Population -North Slope Borough. . ... North Slope Borough Labor Force Estimates (Annual Average) .......... . Population and Employment in Alaska, Anchorage and Fairbanks, 1978 . . .. Future Development Specifications ACMP Conformance Review .... Direct Terrestrial Habitat Loss Due to Pad Expansion or Construction ..... Relative Habitat Value and/or Sensitivity of Terrain Directly Altered by Waterflood Project Facilities •......... Vulnerability of Important Species to Intake Operation Impacts ..•.... Potential 6.5-Month Entrainment of Fish Eggs and Larvae by the Waterflood Intake Based Upon Data Collected from February 13 through September 1, 1979 ..•...•.. Summary of PSD Increment Compliance for the Waterflood Facilities .......... . PAGE 3 -78 3 -79 3 -81 3 -83 3 -89 4 -15 • 4 -23 4 -25 . . . 4 -66 4 -68 Cumulative Air Quality Impacts Prudhoe Bay, Alaska. 4 -83 4 -85 5 - 5 Preliminary Monitoring Program Summary ... xi FIGURE 1 1.3-1 2.2-1 2.5-1 2.5-2 2.5-3 2.5-4 2.5-5 2.5-6 2.5-7 2.5-8 2.5-9 2.5-10 2.5-11 2.5-12 2.5-13 2.5-14 2.5-15 2.5-16 LIST OF FIGURES VOLUME I Proposed & Alternative Actions. Distribution of Prudhoe Bay Oil (1980 Estimate) • Prudhoe Bay Field Oil Production Rate vs. Time. Schematic of Major Alternatives ..... Proposed Waterflood Project Location Map. Proposed Waterflood System Schematic of Waterflow Proposed Dock Modification & Causeway Extension Location Plan . . Clear-Span Bridge ....... . Proposed Causeway Modifications . Proposed Seawater Treating Plant Process Flow Schematic . . . . • . . . . . . . . Alternative Intake Design Concepts ... Proposed Intake System Showing Marine Life PAGE s -10 1 - 3 2 - 6 2 -16 2 -18 2 -19 2 -22 2 -23 2 -25 2 -30 2 -31 Bypass With Eight Fixed Screens . . . 2 -32 Proposed Marine Life Return Outfall Pipeline. 2-40 Proposed Onshore Pipeline Installation Plans & Sections. . . . . . • . . . . . . . . . . . . . 2 -42 Proposed Injection Plant Process Flow Schematic (Typ.)......... . . . • . . . • 2-45 Proposed Injection Well Pad Facility (Typ.) - East Location Plan. . . . . . . . . . . . . . . . 2 -48 Proposed Injection Well Pad Facility (Typ.) - West Location Plan ..............•... 2 -49 Project Schedule Prudhoe Bay Unit Waterflood Project. 2 -14 Estimated On-Site Construction Manpower Requirements Quarterly Average ...•. • xi i 2 -60 FIGURE 2.5-17 2.5-18 2.5-19 2.5-20 2.5-21 2.5-22 2.5-23 3.2-1 3.3-1 3.3-2 3.3-3 3.3-4 3.3-5 3.4-1 3.4-2 3.6-1 3.8-1 3.8-2 3.8-3 3.8-4 Alternative Remote Seawater Intake Structures Plan & Section-(Typical) ....... . Gravel Island Alternative (B) Seawater Treating Plant at DH 3 Alternative C Dock Modification & Causeway Extension Location Plan (Alternative C 1). . ........... . Semi-Elliptical Breach ......... . Alternative Plans for Causeway Breaching. Alternative Low-Pressure Pipeline Routes to West Side . . . . • • • . . . • . . • Known Archaeological Sites at Prudhoe Bay . Village Land Use Areas .... Existing Prudhoe Bay Facilities Map (Apart from Waterflood Facilities). North Slope Borough Land Status . . North Slope Borough Nominations/Selections Municipal Entitlement Act Prudhoe Bay Unit. North Slope Borough Interim Zoning Districts .. Existing and Proposed Prudhoe Bay Gravel Sources. Physiographic Provinces, Drainage Regions, & Key Locations of the North Slope .....•. Migratory Behavior of Selected Prudhoe Bay Animal Species .•.............. Stump Island Migration and Bathymetry Changes . Diagrammatic Representation of the Sequential Erosion of the Head of West Dock & the Artificial Island Niakuk 3 ...•....••...• Salinity (ppt) Distribution at 1m (3.2 ft) on August 13, 1978. . . . . . . . . . ... Bottom Salinities & Topography on August 13, 1978 . xiii PAGE 2 -63 2 -64 2 -65 2 -70 2 -72 2 -76 2 -86 3 - 5 3 -7 3 - 8 3 - 9 3 -11 3 -13 3 -17 3 -18 3 -24 3 -38 3 -40 3 -42 3 -43 FIGURE 3.8-5 3.9-1 3.12-1 3.12-2 3.12-3 3.13-1 3.15-1 3.15-2 3.15-3 4.2-1 4.2-2 4.2-3 Average & Absolute Maximum Retreat of the Edge of Pack Ice Along the Beaufort Sea Boast. Coastal Movements of Anadromous Fish (Conceptualized) .......... . Annual Wind Frequency Distribution .. Occurrences of Prevalent Easterly & Westerly Wind Flow During the Summer Season at Barter Island, Alaska from 1964 to 1974 .•.......• Wind Rose Prudhoe Bay-Drill Pad A July 1, 1979 to September 30, 1979 . • • . . • • Noise Measurement Locations .• Oil & Gas Potential Development . Regional Aspects of Potential Arctic Oil and Gas Development · •..... Principal Oil & Gas Formations .. Insulation/Gravel Cost Comparison . Predicted Circulation Patterns ..•. Predicted Salinity Changes Induced by Causeway Extension ......... . xi v · PAGE 3 -48 3 -55 3 -65 3 -67 3 -68 3 -71 3 -87 3 -88 3 -90 4 -19 4 -37 4 -38 --.-.~--~-~-~---.....,---o--;--v-----.:"<l"·-· -.....--,--,.~--~--~ .. ·=··-· ....,......,..,.~---~ .. --~---·~-.--·-r--~----------·---·-------·~-~. ~------------------~-------· - APPENDIX VOLUME I I* APPENDICES A RESULTS OF SCOPING B APPLICANT• S PROPOSED PROJECT --DETAILED DESCRIPTION C PHYSICAL AND CHEMICAL OCEANOGRAPHY D HYDRODYNAMIC AND WATER QUALITY MODELING OF SIMPSON LAGOON AND PRUDHOE BAY E MARINE BIOLOGY F FRESHWATER RESOURCES G ACOUSTICS H ENTRAPMENT, IMPINGEMENT AND ENTRAINMENT IMPACTS I COASTAL PROCESSES J ASSESSMENT OF ICE FORCES, ICE OVER-RIDE AND EMBANKMENT STABILITY K RESERVOIR ENGINEERING L TERRESTRIAL HABITAT MAPPING AND EVALUATION M THE RELATIONSHIP OF INCREMENTAL OIL FROM THE PRUDHOE BAY FIELD TO THE U.S. ENERGY BALANCE N ENDANGERED SPECIES ACT COORDINATION 0 AUTHORIZATION TO DISCHARGE UNDER THE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM P PREVENTION OF SIGNIFICANT DETERIORATION (PSD) OF AIR QUALITY *Volume II was issued with the DEIS and has not been reprinted. VOLUME I II PUBLIC COMMENTS AND RESPONSES APPENDIX B CORRECTIONS APPENDIX E CORRECTIONS APPENDIX H REVISED APPENDIX L CORRECTIONS APPENDIX 0 REVISED APPENDIX Q (NATIONAL HISTORIC PRESERVATION ACT) SUMMARY INTRODUCTION The Alaska District Corps of Engineers is considering issuance of three permits to Sohio Alaska Petroleum Company and ARCO Oil and Gas Company (applicants) for construction and operation of a project at Prudhoe Bay, Alaska. This project is proposed by the applicants to produce an additional 1 billion barrels (bbl) of crude oil through waterflooding the currently producing reservoir about 2740 m (9000 ft) below the earth•s surface. It was determined that issuance of these permits, applied for under Section 10 of the Rivers and Harbors Act of 1899 and Section 404 of the Clean Water Act, would be a major Federal action significantly affecting the human environment. It was therefore necessary to prepare this environmental impact statement (EIS) to serve as an important aid in the permit decision making process. After final EIS coordination, the decision document will be prepared where ultimately the District Engineer will issue, deny, or issue with stipulations, the permits sought by the applicants. At the beginning of the EIS preparation process, a concerted effort was made to identify the significant issues related to the proposed action and to assess the amount of existing relevant information. This effort, termed scoping, was carried out in several ways. Formal public meetings were held in Anchorage, Fairbanks, Kaktovik, Nuiqsut, and Barrow, Alaska during November and December 1979. These meetings were preceded by the distribution of in format ion brochures and media coverage. Numerous other meetings and discussions were held with interested agencies, the academic community, the applicant and other elements of the public. Results of scoping were mailed to interested parties and comments invited. The Draft Environmental Impact Statement (DEIS) was circulated for public comment in early June 1980 with the formal comment period ending 31 July 1980. Additionally, a public hearing on the EIS was held in Barrow, Alaska, 15 July 1980. Significant issues related to the proposed action derived from these efforts and later study are: Effects on fish and lagoon systems from the existing and proposed extension of the causeway into the Beaufort Sea. Effects on marine life from the seawater intake and discharge. The effect on subsistence resources and other cultural aspects important to the native Inupiat people. The cumulative effect of the action. The need for energy and effect of a delay on annual and total production of oil and gas. S-1 A significant body of information exists about Alaska's North Slope and Beaufort Sea. However, most scientific studies are of relatively recent origin, progressively conducted as a part of the International Biological Program and in response to the prospect for development of oil and gas in the vast National Petroleum Reserve, the Prudhoe Bay area, and in the Beaufort Sea (Outer Continental Shelf Environmental Assessment Program, OCSEAP). Although much of the EIS is based on existing information, it was determined that additional study was needed in the primary impact area concerning water quality, effects of the proposed causeway and its alternatives, sediment chemistry, wetlands and wildlife habitat, and archaeological resources. Other essential information relevant to potentially significant adverse impacts was not collected because of the limited prospects to resolve scientific uncertainty by application of tne state-of-the-art and because the costs in time and money to advance the state-of-the-art were excessive. Therefore, as required by r~gulations of the Council on Environmental Quality, a reasonable worst-case analysis was applied to the following effects: Reduction of anadromous fish populations because of blocked or impeded along-shore migration. · Reduction of fish populations and other marine biota because of the seawater intake. Reduct ion of the value of Simpson Lagoon for fish and other animals because of ecosystem changes caused by the proposed causeway extension. Occurrence of a seawater pipeline break and effects on tundra ecosystems. Occurrence and effects of emergency waste discharges into the Beaufort Sea. AFFECTED ENVIRONMENT The North Slope of Alaska is a vast wilderness with small, widely s.cattered settlements of the native Inupiat people. The Prudhoe Bay area is an enclave for oil and gas development in the high Arctic, visually dominated by oil drill rigs, processing facilities, and gravel roads. The nearest native village is Nuiqsut, located on the Colville River about 65 km (40 mi) west of the Prudhoe Bay development. Another vil:lage, Kaktovik, is about 175 km (110 mi) east of Prudhoe Bay on the coa~t of the Beaufort Sea. The North Slope has been home for the Eskimo for more than 2500 years. Prudhoe Bay has rapidly developed since oil discovery there in 1968. There is a significant potential for future hydrocarbon exploration and development in the 170-km (105-mi) distance between the Canning and Colville Rivers and offshore in the Beaufort S-2 Sea. Drill pads, artificial islands, pipelines," roads, and possibl"y marine causeways, would accompany ~his activity. The applicant's proposed action and its alternatives relate to secondary recovery of an oil reservoir already under production, the Sadlerochit Formation. The Sadlerochit has estimated recoverable reserves of about 9.6 billiion bbl. It is predicted that approximately 8.42 billion bbls can be recovered through gravity drain age and pressure rna intenance (primary recovery). Recovering the remainder will require secondary recovery measures, such as waterflooding. Since the reservoir is currently under production, however, timing is essential to prevent reservoir damage. Although the Arctic Coastal Plain and the Prudhoe Bay primary impact area have a 13-cm (5-in) annual precipitation rate comparable to that in very dry environments, they are characterized by wet 1 ands, beaded streams, and small lakes. This phenomenon occurs because permafrost, extreme cold, long winters, and flat terrain effectively concentrate water on the tundra in the ice-free season (about 3 months), which corresponds to the period of most active vegetation and soi 1 development. Wildlife in this area are largely migratory. This behavioral adaptation to dramatic seasonal changes and survival opportunities is one of the most sensitive aspects of maintaining viable fish and wildlife populations on the North Slope and in the coastal waters of the Arctic Ocean. Wildlife species that depend on the Prudhoe Bay primary impact area travel great distances. The annual flight of black brant from their wintering areas in California and Oregon charac- terizes many species of waterfowl that depend on wetlands in the area. Wading birds, exemplified by the sanderling an~ pectoral sandpiper, fly even greater distances, arriving on the high Arctic Coastal Plain for nesting from Argentina and Chile. The Central Arctic caribou herd moves from winter ranges near the Brooks Mount a in Range northward to the coastal area each spring. Likewise, anadromous fish species essential in the native subsistence resource base for the villages of Nuiqsut and Kaktovik are very dynamic in the primary impact area. Adult arctic char, least and arctic cisco, whitefish and other species move annually from the Colville, Sagavanirktok and Kuparuk Rivers to shallow coastal waters of the Beaufort Sea to feed, returning each fall to their natal freshwater streams to spawn and overwinter. Although studies are lacking in this area, the ability for anadromous fish to move signi- ficant distances along shore is believed essential in maintaining abundant populations. This is an important consideration in the applicant's proposed causeway extension and its alternatives. The species discussed above and the ecosystems they represent are linked to the Eskimo both culturally and by diet. Recent technological changes and the Eskimo's organization into functioning political and economic units have not significantly altered the traditional Inupiat view of their close relationship to the 1 and and sea. Fish, waterfowl, caribou, whale, and other species are important in their diet from both a biological and psychological perspective. S-3 .i ' From an engineering point of view, oil and gas development in the Arctic requires that great· attention be given to the effects of extremely low temperatures and dq.rkness during winter months. Permafrost, strong winds, isolation, hi.gh labor and materials costs, worker safety, and ice formation and forces are major items affecting design, construction, and operation. · Understanding the significance of the affected envir9nment, then, centers on six important aspects: The Prudhoe Bay area primarily affected by the proposed action is a developed area but has a considerable amount of important habitat. :: Free movement of wildlife and anadromous fish populations is important: in local, international, and intercontinental perspect iV,es. Natural resources and kinship are important to the stability of the Inupiat culture. I Certain natural systems in the Prudhoe Bay primary impact area (wet graminoid tundra, drained lake basin complexes, the coastal lagoon, and others) are of relatively high value as habitat for important species of birds, other wildlife, and/or marine biota. There is a significant need for energy and the potential recovery of 1 billion bbl of domestic oil is a rare occur- rence, making the proposed action equivalent to finding a world class, giant oil reserve. Engineering works in the Arctic require special consider- ations related to permafrost, sea ice, extreme cold, other adverse weather conditions, highly sensitive habitat, high costs, and increased risk to human safety. ALTERNATIVES AND ENVIRONMENTAL EFFECTS A systematic approach was taken to assess alternative ways to meet the energy needs addressed by the applicant • s proposed project and to meet the various 1 aws and governmental policies established to conserve the human environment. Alternatives were 1 imited to those that were reasonable from an engineering, economic, and environmental point of view. No Action This alternative would result in a decline in natural production at the Prudhoe Bay Oil field without secondary recovery by source S-4 waterflooding. With the no action alternative 1 billion bbl of oil would be excluded from the future domestic oil reserve. It is possible that some technological advance in enhanced oil-recovery techniques would occur, but this is highly unlikely within the projected 26-year life of the field. With this alternative, ecolog·ical systems in the area otherwise affected would continue to contribute resources for public benefit (i.e., waterfowl, caribou, fish, etc.). From the economic standpoint, with no action the applicant, the State of Alaska, and the Federal Government would be equally .affected. It is estimated that $10 -$27 bi 11 ion would not be gained by each during the 1 ife of the project. The national deficit would suffer by a similar amount through increased purchase of foreign oil. The North Slope Borough would forego about $20 million in property taxes. No action would also mean gas sales and transport through the Alaska Highway gas pipeline would probably not be allowed (see State of Alaska comments, Vol. 3). Perhaps most importantly, however, the opportunity to conserve this significant increment of energy would likely be considerably diminished. Delay Postponing secondary recovery activities 1 -3 years may reduce oil production in the mid-1980's, but would not affect ultimate recovery as long as secondary recovery activities were intensified to "catch up" to required oil reservoir specifications. However, extended delay probably would have an important adverse impact on ultimate oil recovery and a threshold would be reached beyond which the concept of "catch up" becomes impractical. A delay would force society's energy need to be addressed by increases from foreign sources, by increased economic and political pressures to develop other domestic sources, and by forcing more intensive energy conservation efforts. A delay probably would reduce the flow of oil in the trans-Alaska pipeline in the mid-1980's and lower its operational efficiency. Also, delay would require larger facilities at Prudhoe Bay and a greater number of injection wells to accomplish "catch-up." The magnitude of these effects would, of course, increase with delay time. Beneficial effects of delay relate to having more time to assess adverse impacts of alternatives and the increased possibility of avoiding these effects by creative design changes. Also, with more time, the possibility exists that new and better technology may be developed for enhanced oil recovery. Within the 5-year delay time frame, however, this latter development is considered very remote. Alternatives at the National Level Two general approaches exist at the national level to address society's need for energy: reducing demand or increasing supply. On a long-term basis reducing consumption is indeed promising. More stringent measures could be taken to implement this alternative by special legislative and S-5 --l executive action. Implementation of this alternative alone, however, would not conserve oil at Prudhoe Bay through secondary oil recovery and would result in the loss of about 1 billion bbl of oil. The second approach relates to developing new forms of energy, developing new fields, and the use of renewable energy supplies. Much effort is being devoted to this by the government and private sectors. This alternative alone, however, could not be expected, within the time allowed, to make up for the increment of oil not recovered at Prudhoe Bay. Meeting the nat ion's energy needs·· can be accomplished only by a coordinated effort of both reducing demand and increasing supp 1 ies. In light of this approach, it is assumed to be prudent to conserve oil by enhanced recovery where it would otherwise be lost by inaction, and would not cause unacceptable environmental or social effects. Such is the case for the present analysis of. the the Prudhoe Bay oil fie 1 d. Thus, alternatives for enhanced oil rettovery at Prudhoe Bay as discussed below are valid considerations. Alternatives for Enhanced Oil Recovery'(EOR) at Prudhoe Bay Current oil extraction technology provides several recovery methods that were considered in this EIS in addition to waterflooding. These include polymer flooding, carbon dioxide injection, caustic flooding, steam injection, in-situ combustion, micellar solution (chemical flooding), gas injection, well recompletion, artificial lift and low-pressure gathering system, and increasing well density. Physical conditions of the Sadlerochit reservoir preclude several methods mentioned above, while extremely high costs, increased potenti~l for adverse environment a 1 effects, and techn i ca 1 cons ide rations eliminated others from detailed analysis. All methods except in-situ combustion are compatible with waterflooding and some could be viable as tertiary recovery techniques at Prudhoe Bay after waterflooding . . Alternative Ways to Accomplish Waterflooding Alternative ways to accomplish waterflooding relate to water sources, pipeline routes, well pad locations, causeway alternatives, intake alternatives, water treatment, waste. disposal methods, various miti- gation measures, and design modifications. The Beaufort Sea was found to be the only practical source for the large quantity of water necessary {about 2 million bbl/day) to accomplish waterflooding. Alternative locations for an intake in the Beaufort Sea included Simpson Lagoon, Prudhoe Bay and those related to the existing causeway. Those alternatives not related to the existing causeway were eliminated from more detailed consideration because of the lack of a cant inuous, dependable, ice-free water supply, infeasibility due to operation and maintenance problems, and the magnitude of potential S-6 adverse environmental effects. Following is a discussion of the applicant•s proposed project and viable alternatives including the environmentally preferred alternative. All alternatives will allow the production of 1 billion bbl of oil. The Applicant•s Proposed Project In addressing various environmental concerns of agencies and the public, the applicant has made several significant changes in the project previously proposed in the DEIS. The following description of the proposed project includes these changes. Widening and raising an existing 2865-m (9400-ft) gravel causeway in the Beaufort Sea and extending it an add it ion a l 1125 m (3700 ft) into deeper water. A 15-m (50-ft) clear-span bridge would be installed in this extension to aid in fish passage. Electric power lines would be buried for the length of the causeway. Construction and operation of a seawater intake and treating plant (with a flow-through, angled-screen fish bypass system) at the end of the causeway extension with an annual average daily discharge into the Beaufort Sea (north of the extended causeway) of 207 ppm (3.6 tons) of solid materials from the plant. Construction of six new gravel pads and related facilities for pressurizing and distributing seawater to the Prudhoe Bay oil field. Construction and maintenance of about 196 km (122 mi) of pipeline. Widening 27 existing gravel pads and construction of one new gravel pad to accommodate water injection wells. Significant environmental effects would be as follows: During construction about 900 jobs would be created and during operation about 300 jobs would exist. Causeway modifications would cover about 27.1 ha (67 acres) of soft bottom lagoon habitat (important to fish and other organisms) with gravel. The causeway extension and intake may slightly reduce anadromous fish populations in local rivers (perhaps by as much as 3.5 percent for Sagavanirktok River fish, 2.6 percent for Canning and Colville River fish) by impeding migrations and by entrapment in the water intake. This effect may thereby slightly reduce the subsistence resource base for the villages of Nuiqsut and Kaktovik. S-7 The causeway extension would change about 1670 ha (4130 acres) of Simpson Lagoon to a more marine environment with generally higher salinities, lower temperatures, and reduced currents. Therefore, there may be a decrease in the overall value of this shallow water area as a feeding area for fish, waterfowl, wading birds, and for other animals ecologically linked to these species. On-land modifications would convert about 9.4 ha (23 acres) of high value habitat to gravel pads and about 122 ha (301 acres) of relatively lower value habitat to gravel pads. Adverse cumulative effects relate to past and future reduc- tions of fish populations due to effects of the existing causeway and other development, possible. future marine causeways and intake facilities, and possible oil spills in the Beaufort Sea. Added to past and possible :future actions, this project also would have an adverse effe~t on waterfowl and wading bird populations. The project would contribute to the continuing stress on the Eskimo culture of the North Slope. This stress is related to change caused by increased revenues and to potential adverse cumulative effects on the subsistence resource base. The project could have a positive effect by adding revenues for local social programs, increasing the chance for native employment, and adding an opportunity for positive interaction between industry, the Inupiat people, and government. Other Alternatives to Accomplish Waterflood at Prudhoe Bay Alternatives related to the proposed causeway include the following: Continuous fill causeway. This approach would not include the 15-m ·(50-ft) clear-span bridge currently proposed by the applicant. The magnitude of adverse environmental effects would be increased, but construction and operation costs would be reduced. Culvert breach. The use of a 7.6-m (25-ft) wide culvert in the extended causeway would provide less opportunity for fish passage, but would not significantly alter the potential ecological effects on Simpson Lagoon caused by the causeway extension. Costs would be less than for constructing the proposed bridge breach. Culv.ert breach in existing causeway. A 5-m (16:.4-ft) culvert breach 1n the ex1st1ng causeway potentially would intercept and pass fish at a point where they are most concentrated. Fish movement through this structure cannot be predicted, but S-8 greater survival is possible. Construction costs would be greater and maintenance efforts would be increased because of 2000-ton loading~ Gravel island. With this alternative, the seawater treating plant and intake would be situated on a gravel sea island with the seawater and fuel gas pipelines buried in the seabottom to the existing causeway. This alternative represents the least risk to anadromous and marine fish and would not have any potentially adverse ecological effects on Simpson Lagoon. It would not affect navigation, as do all alternatives related to extending the causeway. This approach also avoids most cumulative adverse effects to the marine environment incurred by the other approaches. However, wh i 1 e this approach represents the least risk to environmental resources, it also represents construction, maintenance, and operation costs that are greater than the applicant•s proposed alternative. This alternative would have somewhat less operational reliability than causeway extension alternatives and would be slightly more hazardous to workers because of its isolation from the. land. Implementation of the gravel island approach would likely result in a project start-up 1 year later than that of the proposed action. Other feature alternatives. A conventional impinge-release trave11ing intake screen is a viable alternative to the currently proposed angled-screen bypass system. It is judged less reliable and significantly more damaging to fish and other sea life than the proposed system. Elevated electrical power lines could be placed along the causeway and extension. These would provide better access for maintenance than the proposed· buried 1 ines but would increase mortality to migrating birds. Alternatives to the on-land parts of the proposed development include other pad locations and expansions, and pipeline alignments. Feasible alternatives that minimize adverse effects of pad expansions are somewhat 1 imited because of reservoir engineering cons ide rat ions and because a certain level of environmental consideration has been applied in selecting the proposed locations. Pipeline and road alternatives are most important as they relate to the western low-pressure distribution line (see Figure 1). Alternative B calls for expanding and upgrading an existing road and pipeline route. This would involve an additional 8 km (5 mi) of pipeline and cost approximately $25 million more than the applicant•s proposed route (A-1). It would also make logistics for future oil field development more difficult, would directly modify more land area, and would be a source of disturbance for a greater road distance. It would, however, represent a reduction in direct damage to high quality habitat and the habitat fragmentation effect of the proposed alignment. S-9 ""0 ~ :E Dol -(I) .., -0 0 a. m :::J < ::;· 0 :::J 3 (I) :::J -Dol (/1 3 I "0 ...... Dol 0 (') -(/) -Dol -(1) 3 (1) :::J - , c@ . .., (I) ONSHORE OFFSHORE ALTERNATIVE A ----(INTAKE & TREATING (PROPOSED PLANT AT END DF ACTION) CAUSEWAY EXTENSION) ALTERNATIVE B ••••••••••••• (INTAKE & TREATING ALTERNATIVE C ---- PLANT ON GRAVEL ISLAND WITH BURIED PIPELINES TO DH 3; ALTERNATIVE PIPELINE) PROPOSED & ALTERNATIVE ACTIONS & WELLPAOS 0 EXISTING FACILITIES • WATER INJECTION PLANTS • INTERMEDIATE MANIFOLDS NOTES: 1. LOCATIONS OF FACILITIES SHOWN ARE APPROXIMATE AND SIZES ARE NOT TO SCALE. 2. ALL HIGH-PRESSURE PIPELINES PARALLEL EXISTING AND PLANNED ROUTES TO BE INSTALLED PRIOR TO WATERFLOOO FACILITIES. / AtRIAL TOI'OORAI'HIC MAN OF I'IIUDHOI! BAY UNIT AREA IV : AIR PHOTO TlCH, INC. O..oi~:July1173 The alternative alignments A-2 and A.:.3 would reduce direct adverse effects on the high value, drained lake basin cqmplex but have adverse effects related to disturbance and habitat fragmentation. Alternative A-2 lessens the fragmentation effect and, with controlled access, would minimize disturbance effects. Costs would be greater, however. The Environmentally Preferred Alternative The Corps of Engineers has identified the following environmentally preferred alternative according to regulations of the President's Council on Environmental Quality: A gravel sea island constructed for location of the treating plant and seawater intake. The main marine outfall line would be located northward of the facility, and the marine life return line would be to the west. Electrical power 1 ines buried in the causeway (not required with gravel island). A state-of-the-art flow-through fish bypass and return system in the intake structure. A 5-m (16.4-ft) diameter culvert breach in the existing c9-useway. Alternative B (Figure 1) pipeline and road alignment. The above components were chosen among feasible alternatives primarily on the basis of ecological and social stability criteria. Implementing these elements would result conceptually in an improvement over present conditions for migrating anadromous fish, theoretically allowing an increase in populations over existing levels. This would avoid additional cultural stress on the Inupiat villages of Nuiqsut and Kaktovik and help assure adequate subsistence resources. Also, no ecological change would occur to lower the value of Simpson Lagoon as a feeding habitat for fish, waterfowl, and other animals related through food chain product ion. This approach would have 1 itt le appreciable adverse cumulative effects on fish populations (entrainment impacts would be similar to those of the proposed project, while impingement and migration barrier impacts would be much less). Also, it would cause the least damage to valuable terrestrial habitat. This alternative represents a "least environmental resource risk" approach to accom- plishing waterflood. It would, however, increase total project costs by about 10 percent, especially through increased operation and maintenance costs, and would probably delay project start-up for 1 year. It represents a decrease in reliability compared to the applicant's proposed project. Efficiency of operation would similarly be reduced. Also, there could be a somewhat increased risk to workers because of the more unreliable transportation link between land-based services and the gravel sea island. S-11 CHAPTER 1.0 INTRODUCTibN 1.1 EIS PURPOSE AND HISTORY An environmental impact statement ( EIS) describes, for pub 1 ic review and consideration, a proposed Federal action that would significantly affect the human environment. This obligation is an intrinsic element of the National Environmental Policy Act of 1969 (NEPA), clarified in regulations of the Council on Environmental Quality (CEQ) and those governing the jurisdiction and authority of the various Federal agencies. In August 1979, Sohio Alaska Petroleum Company and ARCO Oil and Gas Company, as operators of the Prudhoe Bay Unit (PBU), applied to the Alaska District for three separate permits, each of which is necessary before a waterflood of the Prudhoe Bay petroleum reservoir can commence. The District Engineer determined that issuance of these permits, applied for under Section 10 of the Rivers and Harbors Act of 1899 and Section 404 of the Clean Water Act, would be a major Federal action signifi- cantly affecting the human environment, thus warranting an EIS. The Corps established itself as lead agency and requested the National Marine Fisheries Service (NMFS), the U.S. Fish & Wildlife Service (FWS), and the Environmental Protection Agency (EPA), as cooperating agencies, to assist in statement preparation. Scoping meetings among State and Federal agencies, the Corps, iocal governmental bodies, the public, and the applicant were held in November and December of 1979 in Anchorage, Fairbanks, Barrow, Nuiqsut, and Kaktovik. From these meetings, through staff and consultant analysis, and through guidance from cooperating Federal, State, and local agencies, the following significant issues were identified: , Effects on fish and lagoon systems from the existing and proposed extension of the causeway into the Beaufort Sea. Effects on marine life from the seawater intake and discharge. The effect on subsistence resources and other cultural aspects important to the native Inupiat people. The cumulative effect of the action. The need for energy and effect of a delay on annual and total production of oil. A draft EIS was circulated for pub 1 ic review and comment in June and July 1980. A public hearing was held on 15 July 1980 in Barrow, Alaska, to provide the public an opportunity to make comment. This hearing was held jointly by the Corps of Engineers and the U.S. Environmental Protection Agency. In addition to the wide circulation given this 1-1 HUl final EIS, a well-illustrated summary of the document with an Inupiaq translation was made available in greater numbers to affected villages of the North Slope. 1.2 STATUS OF THE PROPOSED ACTION Since the proposed action is related to permit issuance, no construction activity has been undertaken. The applicant has accomplished several years of planning and conceptual design of the proposed action. Detailed engineering design has begun on certain aspects of the project. 1.3 PURPOSE AND NEED FOR THE PROPOSED ACTION The proposed action has many purposes and needs associated with it. The applicant's primary purpose is to efficiently continue long-term oil and gas production from the Prudhoe Bay oil field for the greatest profit. The Corps of Engineers• action will reflect the public interest based on the Clean Water Act, the National Environmental Pol icy Act of 1969, implementing regulations, and other laws and executive policies. In the public interest, the proposed action and its alternatives are essentially re1ated to society's significant need for low-cost energy. The public interest is also vested in the long-term maintenance of a productive and useful environment. Specifically, this case involves a proposal to recover a large quantity of oil (1 billion bbl). It also involves the local, State, and national need to protect valuable land and marine ecosystems that characterize the high arctic region of Alaska and those that are important to the stabi 1 ity of contemporary Eskimo culture. U.S. total oil. production in 1980 is estimated at approximately 9 million bbl/d (Thiel 1979), of which the Prudhoe Bay field contributes 1.5 million bbl via the trans-Alaska pipeline, or about 17 percent. U.S. demand for 1980 is estimated at 18 million bbl/d, and Prudhoe Bay contributes 8 percent of the petroleum to satisfy it. Waterflood would maintain this percent contribution for two additional years, with an increasing contribution to total Prudhoe and U.S. domestic production in the following years. The distribution of Prudhoe Bay oil is shown in Figure 1.3-1. The alternatives (including the proposed action) given greatest analysis are expected to increase recovery from the Prudhoe Bay field by approximately 1 billion bbl of oil. Table 1.3-1 presents a comparison of oil production quantities from the Sadlerochit Formation (Prudhoe Bay field) with and without waterflood, and shows the incremental daily and annual production estimates. The incremental fuel consumption required to inject the water is approximately 5 -10 percent of the additional oil recovered. Benefits from water injection are expected to become evident within 1 -3 years 1-2 ... ~-.. - PBU Waterfrood Environmental Impact Statement 1-3 ,...,. w I-<( ~ -l-en w 0 co m ,..... ""' ..J -0 >-<( m w 0 J: 0 :::> 0:: a.. LL 0 z 0 -I-=> m -0:: l-en -0 Figure 1.3-1 TABLE 1.3-1 EFFECT OF WATERFLOOD ON SADLEROCHIT PRODUCTION With Without Waterflood Waterflood Incremental Production Mill ion Million Million Thousand Year Barrels/Year Barrels/Year Barrels/Year Barrels/Day 1986 547.5 529.6 17.9 49.0 87 547.5 462.3 85.2 233.4 88 524.8' 401.0 123.8 339.2 89 441.7 308.0 133.7 366.3 90 353.4 236.5 116.9 320.3 91 282.7 181.6 101.1 277.0 92 226.1 141.1 85.0 232.9 93 181.0 160.9 70.1 192.1 94 144.7 87.2 57.5 157.5 95 113.5 68.5 45.0 123.3 96 91.7 53.9 37.8 103.6 97 79.1 42.3 36.8 100.8 98 68.2 33.3 34.9 95.6 99 58.8 26.2 32.6 89.3 2000 50.8 20.6 30.2 82.7 1 43.8 16.2 27.6 75.6 2 37.7 37.7 103.3 3 32.5 32.5 89.0 4 28.0 28.0 76.7 5 24.2 24.2 66.3 6 19.7 19.7 54.0 2007 17.0 17.0 46.6 Cumulative Incremental Production 1195.2 Based on Helton Engineering Co. estimates of decline, February 1980 (see Appendix M and Appendix K). 1-4 after the start of injection and will quickly surpass the water injection fuel consumption, resulting in a positive energy impact. Estimates of energy needs for manufacture of equipment are unavailable but are considered small in comparison to e~ergy developed by the project. To place the effect of waterflood in context of national energy production, the incremental reccivery must be compared to the cost (economic and environmental) and probability of finding a similar reserve elsewhere in the United States. Several facts stand out. One billion bbl of oil corresponds :,to about 10 percent of estimated onshore undiscovered recoverable oil reserves in Alaska {Shell 197g, USGS 1975). . A billion bbl field is considered a world-class giant field. At the end of 1976 there were 67 :such fields producing worldwide, having remaining reserves of 1 billion bbl or more. Of these, only four were in the United States (Prudhoe Bay, East Texas, Yates, and Elk Hills). Including these four, there were only six fields in the U.S.,with remaining reserves greater than 500 million bb 1 (Kern River and Wilmington were the other two). Fewer than 1 percent of discovered oil fields exceed 100 million bbl. The total reserves of all new fields (and new reservoirs in old fields) discovered in the U.S. in 1978 amounted to only 273 million bbl. It is highly unlikely that the opportunity exists elsewhere in the U.S. to achieve with a single project the oil productivity of a Prudhoe Bay oil field waterflood within the projected schedule. 1.4 STATUS OF LICENSES, PERMITS AND APPROVALS The current status of the proposed action· in relation to major legislative and regulatory actions governing its implementation is summarized in Table 1.4-1. Many permits, approvals, and policy compliance reviews other than those listed would be necessary before and during construct ion under State and loca 1 statutes and regulations. In addition, other agencies have policy implemeDtation responsibilities that could relate to the proposed action. Those items that could have a major impact on the current progress of the project have been listed in Table 1.4-1. 1.5 FORMAT This document has been organized in accordance with the procedure described in guidelines and regulations published by the President's Council on Environmental Quality (CEQ) (40 CFR 1500-1508) and the 1-5 TABLE 1.4-1 STATUS OF MAJOR LICENSES, PERMITS, AND POLICY COMPLIANCE Statute or Regulation Clean Water Act Section 404 Rivers and Harbors Section 10 Coastal Zone Management Act NSB Interim Zoning Ordinance Endangered Species Act Fish and Wildlife Coordination Act National Pollutant Discharge Elimination System (NPDES) Prevention of Significant Deterioration (PSD) State 401 Water Quality Certification Submerged Tidelands Leasing Gravel Extraction Contract Administering Agency Corps of -Engineers State of Alaska, Division of Policy Development and Planning North Slope Borough Fish and l~ildl ife Service; National Marine Fisheries Service Environmental Protection Agency Alaska Department of Environmental Conservation State of A 1 ask a, Department of Natural Resources Status Evaluations under these statutes prompted preparation of this EIS; opinions are being studied concurrently with Final EIS coordination. Permit applications made August 1979. Consistency determinations under this statute deferred pending water quality analysis results and review of the FEIS. Under the ordinance no-permit is required for the waterflood project except gravel extraction and activities and facilities seaward of DH 3. North Slope Borough is being advised of the progress of EIS work. No determination yet made regarding the subject ordinance's influence on proposed action. The Fish and Wildlife Service and National Marine Fisheries Service are both cooperating agencies in th1s EIS; formal consultation with FWS completed. NMFS consultation completed. Project does not threaten endangered species. EPA is a cooperating agency in this EIS and agency concerns under subject regulations will be addressed. Revised NPDES application submitted March 1980. PSD application made October 197g; declared complete December 1979. Preliminary determination (of approv- ability) made June 21, 1980. Currently being reviewed. Application for a tidelands lease submitted April 1980 for existing and proposed causeways with action expected in September 1980. A 5-year gravel extraction contract for the Applicant's Prudhoe Bay operations was submitted in May 1979. 1-6 Corps of Engineers (33 CFR 230) implementing regulations, both of which fulfi 11 the intent and specifications of NEPA. · \ ' Important conclusions and essential information are presenteq in the Summary preceding the main document. Alternatives to the proposed action are discussed in Chapter 2.0, which is the heart of the document, providing the analytical framework within which subsequent sections examine the existing environment and assess potential impacts of alternatives, including the proposed action. Descriptions of the existing environment in Chapter 3.0 are limited to information necessary for performing the impact analysis. In Chapter 4.0, the: proposed action and alternatives are superimposed on existing conditions to assess impacts. Chapter 5.0 provides a summary of potential monitoring programs that may be instituted to evaluate various aspects of the project, along with a discussion of conditions that may be P.l aced on permit approvals to maximize environmental protection. Subsequent sect ions describe the report authors • qua 1 ifi catipns, the nature and results of public involvement programs. A reference list, glossary, and an index are included. Additional background information is provided in the several appendices. In revising the draft EIS, an additional volume (Volume 3) was produced that contains comment letters, responses, the transcript of the public hearing, and corrections to Volume 2, the Appendices. Volume 2 was not reprinted. 1-7 CHAPTER 2.0 ALTERNATIVES 2.1 INTRODUCTION This section presents the proposed action and its alternatives, together with a summary of their potential impacts. A systematic approach was taken to assess alternative ways to meet the energy needs addressed by the applicant•s proposed project and to comply with the various laws and governmental policies established to conserve the human environment. Detailed analyses of alternatives were limited to those that were reasonable from an engineering, economic, and environrJ!ental point of view. The major alternatives and their impacts have been synthesized into a matrix (Table 2.1-1) to facilitate comparison. The following sections are organized according to four levels of alternatives progressing from 11 no action 11 to site-level design alter- natives. The no act ion alternative, taken as abandonment of secondary oil recovery efforts of the Sadlerochit reservoir at Prudhoe Bay, is presented first. This is followed by an assessment of possible actions at the national level that could address society•s energy needs. Thirdly, alternative methods to enhance oil recovery at Prudhoe Bay are presented. A fourth sect ion presents alternative ways to accomp 1 ish waterflooding of the Sadlerochit Formation oil reservoir. It is in this final section that the applicant•s proposed project is presented, alternatives to each of the major project component parts are examined, and the environmentally preferred plan is identified. · Administratively, the alternative act ions avai 1 able to the Corps of Engineers fall into four broad categories. Some alternatives, such as regulating national oil consumption and supplies, are outside the jurisdiction of the Corps and beyond the capability of the applicant to control. Others, such as variations of the dredge and fill activity required for road and pipeline construct ion are both with in Corps • jurisdiction and within the applicant•s control. Other alternatives, while within the applicant • s control, are outside Corps • jurisdiction but within the jurisdiction of another agency (i.e., methods to control air pollution). Development of other nearshore areas by others as an alternative to waterflood is an example of the fourth category; actions within Corps• jurisdiction but outside the applicant•s control. Several different geographic frames of reference are used in examining the alternatives. Assessment has been accomplished with in a primary impact zone of the Prudhoe Bay area identified as the coastal and nearshore areas between the Sagavanirktok and Kuparuk Rivers (see Figure 3 .3-2). For a broader perspective, the 11 Prudhoe Bay region 11 (defined as the area from the Canning River to the Colville River) serves as a reference for secondary and cumulative impact assessment. An even greater geographic area is at times needed. The North Slope (north of the Brooks Range between Point Hope and the Canadian border) and national and international references are used to present certain 2-1 l N I N /, I NO ACTION (No Secondary Recovery) WATERFLOOD SECONDARY RECOVERY(a) (Proposed) INTAKE CONFIGURATIONS(b) A (Breached Extension; Proposed) B (Gravel Island; Compared to Proposed) ONSHORE CONFIGURATIONS(c) A (Direct Route; Proposed) B (via CCP & GC 3; Compared to Proposed) C (via A-3 Modified Direct · Route; Compared to Proposed) DELAYED WATERFLOOD (Compared to Proposed Action) >-· (!)<ll a:::) IJJ c:ig ~--~ IJJ<[ Zt!l LOSS GREATEST (1 billion bbl) LESS TABLE 2.1-1 COMPARATIVE IMPACTS OF ALTERNATIVES u. ~ 0 f3 (1)-10:: <ll<tu 00:<[ ....... ~ (I) I-t;~~ IJ.Ja::m f!:IJ.JI-1 0 . NONE 206 15.1 NONE 17.9 SLIGHT INCREASE -I IJJ >~ <[r<'l a::'O (!)~ NONE 3,300,000 1,400,000 . 715,000 130,000 NONE 147,000 SLIGHT INCREASE g IJJ -I u <[ Z>-- <[0::1!: ~gf3 ::)<I: a::~ 1-a::a::o !a£!1JJ_ O::li;I-ID NONE LOW MODERATE NONE DECREASE SLIGHT INCREASE .... ~ <[>-ZI->-o-u _ _.z !;(iiiiJJ a::::f!J IJJ..Ju. O.IJ.Ju. OO::IJJ HIGHEST HIG!-IEST.. DECREASE HIGHEST DECREASE SAME SAME :51-~ (/)- (/liD 91 f-IJ.Jcn UZIJJ IJ.Jii: a:: 0::<[ u o:ES NONE 67 . ...... 97 4o(e) SAME a. ;;t ... ::li; i=~~ Z-' IJJU.:I: 1-ZI-oo-a.u3: NO YES YES . NO YES NO YES YES ALT. SECONDARY RECOVERY METHODS (Compared to Proposed Action) LE.SS UNKNOWN(d) UNKNOWN(d) I UNKNOWN(d) LESS UNKNOWN(d) I UNKNOWN(d) (a)Total amount or effect of Proposed Action. (b)Amount or effect due to alternative intake configurations only. (c)Refers only to amounts or effects associated with alternative routes of low-pressure pipeline from base of causeway to the West Injection Plant (d)Amount is not known exactly but probably greater than Proposed Action. (e)rncludes area dredged to lay pipelines to island; this area would recolonize over a period of years. IJJ u<ll ZIJJ u.IJ.Ju ol-a:: !Q::) (l)<llO (I)ID(I) O::)IJJ ..J(/)0:: NONE POTENT! ALLY SIGNIFICANT LOW NOT SIGNIFICANT MINOR DECREASE DECREASE UNKNOWN(d) N I w I ! NO ACTION (No Secondary Recovery) WATERFLOOD SECONDARY RECOVERY(a) (Proposed) INTAKE CONFIGURATIONS(b) A (Breached Extension; Proposed) B (Gravel Island; Compared to Proposed) ONSHORE CONFIGURATIONS(e) A (Direct Route; Proposed) B (via CCP & GC 3; Compared to Proposed) c (via A-3 Modified Direct Route; Compared to Proposed)) DELAYED WATEHFLOOD (Compared to Proposed Action) ALT. SECONDARY RECOVERY METHODS (Compared to Proposed Action) (a)Total amount or effect of Proposed Action. 0 1- ~ ILl ~>-Q o:~:o::m moiLI 0:::1-z i=~a: (/)~<{ o:::E:::E NONE LOW LOW SLIGHTLY LOWER -- -- -- SAME(f) TABLE 2.1-1 (Continued) COMPARATIVE IMPACTS OF ALTERNATIVES ...J z "'>-z 0 ot-o 0>-9:J-t!>t- z"'> <~:!:( z ~:::>...J o...Jz o...J- "=> zl- 1-o:::O 1-f!O t-oo 0(/):::> ~11.1!!: o(/)c;; 11JQ.O 1-0 ~<1:0 u..~O lt~tO u..oo:: LL..-0::: 11.1011.1 ILl (J)Il. NONE NONE NONE HIGHEST MODERATE POTENTIA~Ll MODERATE c HIGHEST MODERATE POTENTIA~Ll MODERATE c MUCH MUCH MUCH LOWER LOWER LOWER ------ ------ -- ---- SAME SAME SAME UNKNOWN(g) UNKNOWN(g) UNKNOWN(g) UNKNOWN(g) (b)Amount or effect due to alternative intake configurations only. 0 ...... 1-z z z 0 QILI 1-t-> 0 u =>i=(J) !!!<1:1-(/)I-~ :::>...J 1-<1::::> 0:::<1: o::...Jo t-=>11.1 o_l-1-Iii =>:::E z:::ELL. ILIIl....J :g~~tO LL.:::>:::> o:::>LL. lt~o ()()ILl 00<1:0 NONE NONE NONE/NONE SIGNIFICANT POTENTIALLY $2.0 Billion/ SIGNIFICANT $60-70 Mi 11 ion SIGNIFICANT LOW BASE/BASE NONE NONE +$66 Million/ +$6 Mi 11 ion MODERATE SLIGHT BASE/BASE $25 Mi 11 ion/ SLIGHT SLIGHT +0.2 Million SLIGHT SLIGHT +$5 Mi 11 ion SLIGHT SLIGHT GREATER/ INCREASE INCREASE GREATER UNKNOWN(g) UNKNOWN(g) ,I GREATER (per bbl recovered) (c)cannot be accurately determined; productivity considered to decrease; some 1560 ha (3900 acres) inside Stump Island would be affected. (d)Applicant's rough estimate only. (e)Refers only to amounts, effects associated with alternative routes of low-pressure pipeline from base of causeway to the West Injection Plant. (f)same ultimate effect as proposed, but resource value continued up to 5 ye~rs. (g)Amount is not known exactly but probably greater than Proposed Action. values, describe the dynamic and far-ranging wildlife species that depend on the habitat to be affected, and present the oi 1 supply situation or other considerations. Time referencing is also important in gaining a depth of understanding for issue~ at hand. The past, present, and future are often mentioned. Consultation with the U.S. Fish and Wildlife Service (USFWS) and the National Marine Fisheries Service (NMFS) resulted in the determination that there are no endangered or threatened species that would be adversely affected by the proposed action (Appendix N). An on-site reconnaissance survey was performed, and the : 1 atest edit ion of the National Register of Historic Places (and its:, supplements) has been consulted. It is concluded that neither the proposed action nor any alternatives considered in detail in the EIS would have an effect on historic or prehistoric cultural resources;. The State Historic Preservation Officer concurs with this 11 no effect~· finding. Certain conditions and processes are especially i~portant in considering the significance of the affected environment and practical alternatives. The Prudhoe Bay primary impact area is. a developed area, but has a considerable amount of important habitat. The free movement of wildlife and anadromous fish is important in local, international, and intercontinental perspectives. Natural resources are important to the stablity of the Inupiat culture. Certain natural systems in the Prudhoe Bay area (wet graminoid tundra, drained-lake basin complexes, the coastal lagoon, and others) are of relatively high value as habitat for important species of avifauna, wildlife, and/or marine biota. There is a significant need for energy at the national level. The potential recovery of 1 billion bbl of domestic oil is a rare occurrence, making the proposed action equivalent to finding a world-class giant oil reserve. Engineering works in the Arctic take certain special considerations related to sea ice, permafrost, extreme cold and other adverse weather conditions, highly sensitive habitat, high labor costs, and increased risks to human safety. 2-4 ---w --; FZFFT 2.2 NO ACTION AND DELAY ALTERNATIVE NO ACTION The no action alternative is defined as not granting permits with the subsequent abandonment of secondary oil recovery of the Sadlerochit Formation in the Prudhoe Bay field by source waterflooding. Under this option, the field would continue to produce under other existing and planned procedures. These procedures include: Natural gas reinjection. Well recompletion. Artificial lift and low-pressure gathering system. Possible increased well density from one well per 65 ha (160 acres) to one per 32 ha (80 acres). Gas injection is already underway and is intended to continue until gas sales commence. Recompletion involves a variety of procedures for maintaining well productivity, all of which are common practice in the industry and applicable at Prudhoe Bay. Included in the approved PBU plan is a systematic shut-off of non-productive oil zones or zones that contribute an unacceptable amount of gas or water, and a concurrent opening of zones that will be more oil productive. Artificial lift and a low-pressure gathering system are included in the current field development plan. Well density is currently set at 65 ha (160 acres). If production history an~ monitoring of reservoir pressure indicate inadequate drainage, the Alaska on--and Gas Conservation Commission may deem it beneficial to increase well density to a 32-ha (80-acre) spacing. This would double the number of existing wells from approximately 500 to 1000 and would require additional related facilities. It is expected that this will take place at some time in the future. These techniques are applicable with or without a secondary recovery approach and would not achieve the incremental recovery intended by waterflooding (Figure 2.2-1). Van Poollen (1980) presents a graphic comparison of four basic alter- native production scenarios, which are: Case 1. No waterflood and no gas sales. Case 2. Waterflood without gas sales. 2-5 l 10.0 0 z 0 j: w ...J a. ::::E 0 0 .... 0 ...J w CD a: CD ...J 0 ...J z w 0 ;= :1 t ULTIMATE OIL RECOVERY ...J 3 ...,-\·:~ • % v r-•• .. Case Billion bbl on-rn-place ui / • •• . . . --~ . ·. • • • <1.0 ·~ "\.• " . c 1 8.42 40.8 = a: ~ ,, .. • z 0\ \. . -- 0 . . .2 9.51 46.1 - j: ~ ·~ " ·. 7-/ -0 ~ ~\.. ' .. ~: 7.42 35.9-;:) 0 '~ '~:y 0 . a: ~~ "'~;. 9.37 45.4-a. ~'ti ...J 0 ' .......... Case 1 No waterflood, no gas sales \ .. -·-Case 2 Waterflood without gas sales ,, -1 ~~~·----case 3 Gas sales without waterflood •• • • ••• Case 4 Waterflood and gas sales . !'....:'· .... ' ·. -..........:::~"-:._-... 0.1 I I I I I I I I I . ' . r-::: r:.:::::--. 1977 1981 1'985 1989 1993 1'997 2'001 2005 2'009 TIME, YEARS Source: Van Poollen 1980 PRUDHOE BAY FIELD OJL PRODUCTION RATE vs. TIME '" P_BJJ Waterfrocrd Environmentar Impact Statement Figure 2.2-·1 2-6 Case 3. Gas sales without waterflood. Case 4. Waterflood and gas sales. ' As shown, gas reinjection in lieu of waterflood (Case 1), while prolonging the life of the field, would result in a lower rate of production and lower ultimate recovery. Although· gas injection is important for reservoir pressure rna intenance in the early years of development, its value (in this respect) will_ drop as the following occurs: Of the gas withdrawn, only 90 percent is reinjected (10 percent lost to fuel field operations). As the volume of oil in the reservoir drops, through production, the ability of the gas to majntain adequate pressure will weaken. This will be compounded by the lower volume of gas being reinjected than was withdrawn, and the fact that the gas is more mobile in reservoir rock than a fluid; the fluid's energy would be more contained by the reservoir, hence more effective at "pushing" oil, whereas the gas would be more susceptible to absorption with the rock, and lost. The no action option could be mandated by denial of critical permits, eitner by the Corps or other agencies. Thus, the alternatives of action or no action are at least partially within Corps' jurisdiction, and perhaps partially within applicant's capability in that available steps to avoid permit denial are bounded by technical and economic limitations. Such a denial would be based on the project failing to pass the Corps' pub 1 ic interest review, or other assessments required under the permit process. If the no action alternative were exercised, the incremental amount of oil available at Prudhoe Bay would be excluded from the future domestic oil reserve and reservoir dynamics would deteriorate, endangering ultimate recovery potential. This would act to decrease available domestic oil, pointing to he.ightened reliance on foreign oil sources. Any increased reliance on imports would be a negative influence on the national balance of payments and tend to render the U.S. economy and security more vulnerable to supply interruptions. Thus, no action would probably result in additional economic and political pressure to develop other energy sources with in a more compressed time frame and tend to reduce consumer use of avai 1 able supplies. No act ion would also mean that gas sales and subsequent transport through the planned Alaska Highway gas pipeline would probably not be allowed (see State of Alaska comments, Vol. 3). With this alternative~ ecological systems in the area otherwise affected would continue to contribute resources for the public benefit (i.e., waterfowl, caribou, fish, etc.) at levels currently contributed. It should be noted, however, that development elsewhere would probably cause environmental effects at least as great as with waterflood. 2-7 From the economic standpoint, no-act ion could be assumed to equally affect the applicant, the State of Alaska, and the Federal Government. It is estimated that without waterflood $10 -$27 billion would not be gained by each during the 1 ife of the project. The national trade deficit could suffer by a like amount through increased purchase of foreign oil. A 1 so, the North Slope Borough would forego about $20 million in property taxes. Perhaps most importantly, the opportunity to conserve this significant increment of energy would be considerably diminished. DELAY The delay alternative is defined as postponement of the proposed action beyond the proposed 1984 start-up date. Delays of a year or more in beginning secondary oil recovery could substantially, reduce oi 1 production in the mid-1980s. Although uncertainty exists, it is estimated that delaying source water injection beyond early 1985 will cause a progressive product ion loss of as much as 0.5 - 1 percent per year of the oil-in-place (i.e. 100-200 million bbl). Thus, a 5-year delay could result in a 2.5 - 5 percent loss of oil-in-place, a loss that would essentially nullify the incremental production gains of waterflood. Extended delays, therefore, could have an important impact on the ultimate recovery potential of the reservoir. · Although ultimate oil recovery may not be highly sensitive to the timing of injection startup if the rate of injection is increased to "catch up" with an earlier inject ion program, there are reasonable 1 imits beyond which "catch-up" rates become impractical. ,, According to studies by the Alaska Oil and Gas Conservation Commission (AOGCC) (Smith 1980), a 3-year delay would require a 12 percent greater injection rate for the remainder of the project to "catch up." AOGCC feels, "This may well be beyond the practical and economic •catch up• limit." Using a 28-year "floodlife," AOGCC calculated "catch-up" rates for 1-to 5-year delays (Table 2.2-1). AOGCC estimates that a 10 percent increased injection rate woulq require some 20 additional injection wells (Smith 1980). An increase in the rate of injection probably would result in a greater rate of terrain-disturbing development because of larger or more faci 1 iti es and the need for a greater flow of flooding mate:ri al. These activities would tend to increase the magnitude, although delay, the adverse environmental effects of secondary recovery. If secondary oil recovery were delayed, the incremental amount of oil available at Prudhoe Bay would be decreased, thereby reducing domestic oil availability in the mid to late 1980 1 s. A delay would reduce the volume of oil in the trans-Alaska pipeline in this time frame and lower· its operational efficiency. Other domestic or foreign oil sources would 2-8 • TABLE 2.2-1 WATERFLOOD CATCH-UP INJECTION RATES No. of Years Percent Delayed Million bbls/day Injection Beyond 1984 Source Water Injection(a) Increase 1 2.08 4 2 2.16 8 3 2.25 12.5 4 2.33 16.5 5 2.43 21.5 (a)Rate required to equal and "catch up" to injection started in 1984 . 2-9 l be used instead, assuming there is no demand decrease to compensate for the loss in potential production. As discussed in Appendix M, this could occur at a particularly critical time in the nation•s oil supply situation. Beneficial effects of delay relate to having more time to assess adverse impacts of alternatives and to avoiding these impacts by creative design changes. Also, with more time, new and better technology may be developed for enhanced oil recovery. Within the 5-year delay time frame, however, this latter development is considered very remote. 2.3 ALTERNATIVES AT THE NATIONAL LEVEL Two general approaches exist at the national level to address society•s need for energy. One is to increase supplies either by boosting domestic production or buying more oil abroad. The second is to reduce consumption by adopting conservation measures, by rationing, and by promoting energy-efficient technology. Both of these actions require a coordinated national effort. Increasing domestic supply relates to developing new sources, increasing yields from existing fields through secondary and tertiary recovery procedures, and using renewable energy supplies. The cost and time lag involved in developing new fields necessitate increased recovery from existing fields to heighten near-term (8 -10 years) production. Opportunities for additional yields from developed fields· of the magnitude available at Prudhoe Bay are considered very rare (PBU l980b}. Application of this approach alone could not be expected, within the time allowed, to make up for the increment of oil not recovered at Prudhoe Bay. Reducing consumption is indeed promising on a long-term basis and could be achieved through a number of means. However, technical problems and development time limit options. The only action that could significantly reduce near-term oH demand would be a change in usage patterns, particularly driving habits and home heating demands. Although in the past consumers have demonstrated a resistance to change, even in the face of sharply increased prices, reduced demand through intensive conservation practices offers a very important and compelling national opt ion because of the significant energy savings that can be made. Meeting the nation•s energy needs can be accomplished only by a coordinated effort to both reduce demand and increase supplies. In light of this approach, it is assumed to be prudent to conserve oil by enhanced recovery methods that do not cause unacceptable environmental or social effects. Such is the case for the present analysis of the Prudhoe Bay oil field. Thus, alternatives for enhanced oil recovery at Prudhoe Bay, as discussed below, are valid considerations. 2-10 2.4 ALTERNATIVES TO ENHANCE OIL RECOVERY Modeling of the Prudhoe Bay field is a continuing effort by the Alaska Oil and Gas Conservation Commission and the Prudhoe Bay Unit (PBU) owners and involves periodic updates to incorporate new reservoir and performance data. Results of this effort are applied to decisions about the technical and economic feasibility of production methods. Today•s oil extraction technology provides several recovery methods that could be employed instead of the applicant's proposed waterflood process. Some are still experimental. Others are more widely considered as tertiary recovery techniques that could be applied to a reservoir after the more well-established waterflooding process is complete. Options available for use in place of, or in conjunction with, the waterflood process are described in this section. GAS INJECTION Gas injection is already underway at Prudhoe Bay as a normal operating procedure during primary recovery, and is intended to continue until gas sales commence. As shown in Section 2.2, NO ACTION (see Figure 2.2-1), gas reinjection accompanying waterflood would enhance oil recovery more so than waterflood alone. POLYMER FLOODING Actually an adjunct to waterflooding, this method involves m1x1ng polymeric chemicals with injection water, which imparts to the water an apparent high viscosity. This results in the water being more viscous than the oil and thereby improves displacement efficiency. The best applications of this process are in reservoirs containing more viscous crudes than found in the Sadlerochit Formation. Therefore, this method was not-considered practical. Environmental effects were judged to be greater than with the proposed action. CARBON DIOXIDE INJECTION As much as 12 percent of the gas produced at Prudhoe is carbon dioxide (C02). This C02 would be processed out of the gas when gas sales commence and injected into the reservoir to enchance recovery. Most previous instances of C02 inject ion have been as secondary recovery mechanisms in conjunction with water injection. Process efficiency is still being evaluated. The quantities of C02 that would be available at Prudhoe are substantial relative to sizeable projects now being conducted in the U.S. (Herbeck et al. 1976, Kane 1979); however, it appears the true benefits of C02 injection are best gained in reservoirs with low primary recoveries, relatively low operational cost, and where the C02 is miscible with the crude oil. This is not the case at Prudhoe • 2-11 Bay where primary recoveries are expected to be high, operating costs are high, and the pressure required for C02 miscibility is higher than the original reservoir pressure. Therefore, this alternative was considered as one that could possibly be used in conjunction with waterflooding, but not instead of it. CAUSTIC FLOODING Caustic flooding is another operation that may be conducted in conjunct ion with waterflooding. It has been used 1 argely on an experi- mental basis to date. Its primary function is to alter reservoir rock characteristics and permit the flow of oil preferential to water. It is doubtful, however, that any significant technical benefit for the Sadlerochit reservoir can be gained with this technique at this time (AOGCC 1980}. In addition, the process presents major environmental, logistical, and economical problems of shipping great quantities of caustic chemicals to the North Slope. This alternative was thus eliminated from further analysis. MICELLAR SOLUTION (CHEMICAL} FLOODING Chemical flooding is primarily a tertiary process applied to reservoirs that have been successfully waterflooded. The chemical solution is actually a surfactant material, which is a shortened term for surface- active-agent. These agents are petroleum-based, or manufactured from hydrocarbons, and act 1 ike a detergent. They are very effective in removin.g oil from the reservoir rock, but to efficiently move that oil to the well bore, the micellar solution must be followed by a polymer solution. This means that two chemicals directly related in cost to the price of crude oil must be made available in great quantities. It has been stated that a 40 percent recovery factor of the oil-in-place might be achieved in certain reservoirs of this type with this process (Herbeck et al. 1976}. Assuming that after waterflooding some 12 billion bbls of oil will still be in the ground at Prudhoe Bay, that could imply an additional 4.8 billion bbl. Projected cost, assuming a somewhat 1 imited chemical and polymer slug, could be in the range of $20 billion for the chemical solution and an additional $10 billion for the polymer solution, in today•s dollars. Supplies of surfactant suitable for the high temperature conditions at Prudhoe Bay currently are not available. Since this approach normally requires waterflooding as a prerequisite, it was judged to have environmental effects at least equal to or greater than the proposed action. The high cost and technical problems thus eliminated this alternative from detailed consideration. 2-12 STEJ.lM INJECTION The injection of steam is used primarily to heat a reservoir to a temperature that lowers oil viscos~ty, thereby allowing it to move more easily to the well bore. The practical application of steam is limited to low gravity (less than 20° API) crude oils at less than 915 m (3000 ft) (Interstate Oil Compact Commission 1974). Conditions at the Prudhoe Bay field significantly differ from these specifications. In addition to the engineering infeasibility, environmental effects are judged to be comparable to those of waterflooding alternatives, because a dependable deep-water source possibly would be required and facilities at least equal in land-disturbing impacts would be required. IN-SITU COMBUSTION (FIREFLOOD) This is a process whereby the oil zone is ignited and a burning front is propagated through the reservoir by pumping compressed air down the wells. Oil viscosity ahead of the flame front is lowered, allowing the oil to move more freely to the producing wells in front of the compressed air. There is little evidence in available technical literature to support the economical viability of this process, although there are some successful projects currently in progress. The Glen Hummel Field in Wilson County, Texas, has been referred to as a successful project· although no economics have been reported. The Battrum Field in Saskatchewan, Canada, has been reported as a commercial application of the process (Interstate Oil Compact Commission 1974). For the Battrum Field, it is estimated that the initial investment for . compressor stat ions was 22 times that for waterflood stat ions. The operating expense for the stat ions was estimated at seven times that for waterflood stat ions. Also, the investment needed for fireflood wells and surface facilities are considerably greater than those for waterflooding due to handling fluids that are foaming, emulsified, and corrosive (Coleman and Walker 1967). Reservoir characteristics of fields where it has been successful differ significantly from those of the Sadlerochit Formation of Prudhoe Bay. In both the Glen Hummel and Battrum Fields, primary recovery from the reservoir was low (less than 15 percent of oil-in-place) and they produced a low gravity, viscous, crude oil (18° -21° API). At Prudhoe Bay this method was eliminated from further analysis because of the high costs and technical i n f e as i b i 1 it y . ~ 2.5 ALTERNATIVES TO ACCOMPLISH WATERFLOODING Waterflooding is widely used throughout the U.S. to increase production from existing wells. At Prudhoe, waterflooding would consist of high-pressure injection of treated water into the Sadlerochit Formation, causing oil in the pore spaces of reservoir rock to flow from high- pressure waterflood areas to low-pressure areas at producing wells . • 2-13 At Prudhoe Bay, three alternative water sources were considered: surface water, ground water, and seawater. As discussed below, seawater was found to be the only source that was of sufficient quantity and quality to provide a year-round, long-term reliable source. Primary criteria for the quality of water for injection are that it be non-corrosive of pipes and machinery, that it be essentially sterile, and that it not form chemical precipitates in the formation. The scarcity of year-round surface water in this vicinity is well documented in the 1 iterature and indeed quite apparent because of the freeze depth and duration of freezing. Shallow ground water occurs only in isolated locations, and permafrost precludes aquifers of suitable size. Deep subsurface water (water occurring in conjunction with petroleum or in non-oil bearing Cretaceous formations) was considered a possible source of ground water. However, this source is considered infeasible as a primary source for waterflooding due to limited volumes and poor quality, forming precipitates upon inject ion into the oil- bearing fQrmation. Various locations in the Beaufort Sea were considered for the source of water: Prudhoe Bay, off the Sagavanirktok River delta, in Simpson Lagoon, and off DH 3 (applicant's proposed location). Because Prudhoe Bay is shallow and freezes to the bottom in many areas, a year-round seawater source located inside Prudhoe Bay would require a 7.7-km (4.8-mi) communication channel through the shoal area at the mouth of the bay. This dredged channel would lead to the end of a new 900-m (3000-ft) causeway extending from shore approximately 3.2 km (2 mi) northeast of the Central Compressor Plant (CCP). This causeway would be necessary to avo·id dredging in the permafrost close to shore, and to carry pipelines. (Dredging of coastal permafrost areas and burial of heated pipelines could lead to permafrost degradation and accelerate coastal erosion.) Predicted siltation of the channel (requiring periodic, perhaps annual, maintenance dredging), coupled with anticipated inferior water quality during the open-water season (cf DH 3~ vicinity), led to the elimination of this alternative. Placement of pipelines on an elevated trestle structure was considered, but rejected because it currently is not considered feasible in the rigorous environment of the Beaufort Sea. Dredging a channel through the shoal at the mouth of Prudhoe Bay would have a significant effect on the bay. Denser, more saline waters that currently tend to be trapped in deeper portions of the bay would drain to deeper water offshore. This would reduce the overall salinity in the bay and might allow a greater portion of it to freeze to the bottom. In addition, the actual dredging activities would cause temporary loss of benthic organisms along the entire channel length. A new causeway could be constructed, but it would interfere with existing circulation patterns in the bay and would also act to interfere with nearshore fish migration patterns. A general policy of both State and 2-14 Federal agencies is to m1n1m1Ze further construction pf causeways along the Beaufort coast. This alternative was therefore rejected from further consideration. To develop a seawater location off the Sagavanirktok River delta, a 7.2-km (4.5-mi) roadway would be required from DH 1 along the east side of Prudhoe Bay to the river delta. From the shoreline it is approximately 4.6 km (2.9 mi) out to the 3.7-m (12-ft) water depth. The lengthy new road and pipeline systems required ,for this alternative would disrupt considerable wetland and other tundra areas. Depending on causeway location, bridging one or more of the river•s distributaries would be needed. A solid fill causeway off the Sagavanirktok delta would severely disrupt the normal pattern of freshwater flow into the coastal waters and would have significant biological ramifications. This alternative was therefore not advanced for detailed assessment. Selecting DH 3 or its proximity as a site for the intake provided a centrally located site with respect to the onshore facilities, thus reducing access roads and pipeline lengths. In addition, DH 3 penetrates far enough into marine waters to overcome subsea permafrost degradation that could be incurred by buried pipelines in the nearshore waters. In general, waterflooding the Prudhoe Bay oil pool with seawater would require a system comprising the following: A means of acquiring and treating seawater. A means of distributing the treated water to appropriate injection locations around the field. There are several feasible alternative configurations such a system could take, offshore and onshore (see Figures 1 and 2.5-1). The applicant has proposed a configuration that consists of: 1. Offshore An integral seawater intake and treating plant at the end of an extension from DH 3 to the 3.7-m (12-ft) water depth. The causeway extension would be breached at its base with a 15-m (50-ft) wide open-span bridge, or equivalent. · 2. Onshore Low-pressure pipelines branching east and west from the West Dock base to injection plants adjacent to Gathering Center 1 and Flow Station 1, from which high-pressure pipelines would deliver water to injection wells throughout the developed area of the field. 2-15 I" THE SEAWATER INTAKE AND TREATING PLANT COULD BE LOCATED .... AT THE END OF A 3700-FOOT CAUSEWAY EXTENSION FROM DH 3 TO 12 FEET OF WATER, WITH A BRIDGE BREACH NEAR DH 3. t APPLICANT'S PROPOSAL AS PROPOSED, BUT WITH A BRIDGE BREACH NEAR THE TREATING PLANT, A BREACH NEAR DH 3, AND A BREACH IN THE EXISTING WEST DOCK TO 2 DH 3 AT THE 3-FOOT DEPTH. AT DH 3, 3 WITH A DREDGED CHANNEL TO THE 12-FOOT DEPTH TO,SUPPLY WATER. FROM PAD K TO PAD E VIA A WESTERN $-ALIGNMENT. FROM PAD K TO PAD E VIA AN EASTERN D-ALIGNMENT AROUND THE SENSITIVE WETLANDS. FROM THE BASE OF THE WEST DOCK, THE LOW-PRESSURE PIPELINE SERVING THE WEST SIDE COULD BE ROUTED ... ON A GRAVEL ISLAND WITH BURIED PIPELINES TO DH 3. SCHEMA TIC OF MAJOR ALTERNATIVES ---. PBU Waterflood Environmental Impact Statement 2-16 4 ON A GRAVEL ISLAND, WITH BURIED PIPELINES TO DH 3, AND A CULVERT BREACH IN THE EXISTING WEST DOCK AT THE 3-FOOT DEPTH. 5 ENVIRONMENTALLY PREFERRED ALTERNATIVE . .... Figure 2.5-1 The Corps of Engineers has evaluated this proposal as well as the following alternative configurations (shown schematically on Figure 2.5-1). 1. Offshore a. Adding a second culvert or open-span breach to the proposed causeway extension near the treating plant, and/or a third in the existing West Dock causeway at the 1-m (3-ft) depth, as well as replacing the proposed open-span bridge breach near DH 3 with a smaller 7 .6-m (25-ft) culvert breach. b. Siting the intake and treating plant on a gravel island in 3.7 m (12ft) of water with buried pipelines to DH 3, in conjunction with a culvert breach in the existing West Dock at the 1-m (3-ft) depth. c. Siting the intake and treating plant at DH 3 (obviating a causeway extension) and dredging a channel to supply year-round water. 2. Onshore a. Three alternative routings of the west side low-pressure pipeline across sensitive habitat between Pad K (Term Well A) and Pad E. b. Routing the west side low-pressure line along the existing work pad that connects the CCP to the east-west spine road. These alternatives and the proposed action are discussed in detail in the following sections. THE APPLICANT 1 S PROPOSED PROJECT General Based on public and agency concerns expressed with the project proposed in the DEIS, the applicant has made several changes to incorporate mitigative measures. These have been included in the discussion below. The locations of facilities proposed for the Waterflood Project are shown on Figure 2.5-2. The facilities provide for seawater flow from a Beaufort Sea intake to about 154 injection wells at 28 individual well pads to achieve injection of about 4.07 m3fs (64,200 gal/min) of seawater, supplemented by about 1.84 m3fs (29,200 gal/min) of water produced from the field during oil production. An overall schematic of water flow is shown on Figure 2.5-3. Seawater would be pumped directly 2-17 "' I I ...... (X) ""0 ~~ :e m -<D .., ~ 0 0 a. m :::s < :;· 0 :::s 3 <D :::s -D) - 3 '0 D) 0 -CJ> -m -CD 3 CD :::s - "TT ca· c: .., CD 1\) (11 ~ PROPOSED WATERFLOOD PROJECT LOCATION MAP LEGEND -···--···-···-···-OUTFALL LINE ••••••••••••• LOW~PRESSURE SEAWATER LINES -----HIGH-PRESSURE LINES 111!1111 WELL PADS 0 EXISTING FACILITIES • WATER INJECTION PLANTS • INTERMEDIATE MANIFOLDS NOTE : LOCATIONS OF FACILITIES SHOWN ARE APPROXIMATE AND SIZES ARE NOT TO SCALE. PAD WF-1 WOULD BE BUILT SOLELY FOR THIS PROJECT. OTHERS WOULD BE EXPANDED AS NEEDED. ~'};"ut/ft / r I • ~-!I I 'i;~ / :AERIAL TOI'OOR"'"IC MAl'S OF PRUDHOE BAV UNIT AREA IV : AIR PHOTO TECH, INC. D-.oi~:July1173 J I~ II-! --------------------------------'-------~~~~~~~~~~~~1~1 I I KEY: DIS.MAN. -DISTRIBUTION MANIFOLD INT.MAN. -INTERMEDIATE MANIFOLD FS-FLOW STATION GC -GATHERING CENTER SEAWATER ~-----~ ... , TREATING PLANT SEAWATER ~ r INTAKE SCREENS FILTER FEED PUMPS IN-LINE STRAINERS HEAT EXCHANGERS FILTERS DEAERATION COLUMNS TRANSFER PUMPS OUTFALL LINE I MARINE LIFE RETURN OUTFALL LINE (f);:E (f)W c(I- Q.(/) >->-tll(f) LEGEND 1- 1- ..--, ' r--1 FS2) I '...__, L-~ ... -... ~rrr--- INJECTION PLANT-EAST INLET MANIFOLD INLET TANK -- DIS. ~ BOOSTER PUMPS MAN.I---.. ~1 HEAT EXCHANGERS 1 INJECTION PUMP/ f ,-..... , DRIVERS -L-{ FS 1 I \ I ........ INJ. WELL PADS 2 12 5 18 r-:§:}-- 1 -.... INJECTION PLANT-WEST INLET MANIFOLD INLET TANK I-- DIS. L ./ ' --, FS3 I \ I ... _.- ~ BOOSTER PUMPS MAN.I---... ~1 HEAT EXCHANGERS 1 INJECTION PUMPS/ ~ ,,-, DRIVERS -LIGC 1 } '., _, INJ. WELL PADS E D F INJ. WELL PADS 3 11 4 16 9 17 INJ. WELL PADS 7 15 14 13 INJ. WELL PADS B X A WF1 INJ. WELL ..__:tt}-NT. PADS MAN. H R r 2 M s I ,-N y , ' ----PRODUCED WATER LINES-HIGH PRESSURE SEAWATER LINES-LOW PRESSURE HIGH-PRESSURE LINES L--rGc2'1 a ., , ....__ .... .... _, PROPOSED WATERFLOOD SYSTEM SCHEMA TIC OF WATERFLOW PBU Waterflood Environmental Impact Statement 2-19 Figure· 2.5-3 into a seawater intake and treating plant located at about a 3.7-m (12-ft) water depth at the end of a 1125-m (3700-ft) extension of the existing causeway, also called the West Dock (Figure 2.5-4). A 50-ft bridge breach would be placed at the end of the existing DH 3. The plant would filter and deaerate the seawater and add heat to prevent freezing during transit. Marine life would be hydraulically passed through the system by a state-of-the-art fish bypass system and returned to the sea via a marine life return line, while strainer and filter backwash would be returned to the sea (in a northerly direction) by means of a separate outfall line. The treated, heated seawater would be pumped through two low-pressure pipelines located within the causeway. The existing causeway to DH 3 would be widened and the road surface elevated to accommodate and protect the piping. At the shoreline, the common pipeline route would split and two separate lines would deliver seawater to injection plants, one each at the east and west sides of the field. These injection plants would raise the seawater pressure and provide additional heating for freeze protection. From each injection plant, high-pressure seawater would be pumped to nearby wellpads and to two intermediate manifolds by means of high-pressure pipelines. Produced water from production centers (called flow stations and gathering centers on the east and west sides of the field, respectively) would also be brought to the injection plant and intermediate manifolds. Both seawater and produced water would be distributed through separate high-pressure pipelines to about 28 well pads and transmitted into the Sadlerochit Formation some 2750 m (9000 ft) below the surface. Monitoring and control facilities at each well pad would control injection flow rates, pressures, and water distribution. These facilities and processes are summarized in the following paragraphs by type of facility and are described in more technical detail in Appendix B, Project Description. Project impacts on specific aspects of the natural and human environment are supplemented by more detailed discussions in Chapter 4.0. Cumulative impacts are summarized as appropriate in this section and analyzed in detail in Chapter 4.0. The reader should also refer to Section 3.15 for a discussion of the future without the project to gain added understanding of North Slope development of which the proposed action would be a part. Causeway Extension and Modifications Description Vehicle access to the seawater intake and treating plant is the primary advantage to extending the causeway; however, the applicant notes that the causeway extension would also result in other operational benefits such as protection of, and ease of access to, the fuel gas line and the low-pressure seawater transfer lines. The applicant proposes to extend the existing causeway to DH 3 an additional 1125 m (3700 ft) into the Beaufort Sea (Figure 2. 5-4). A 15-m (50-ft) open-span bridge breach (Figure 2.5-5) would be incorporated outside of DH 3 to provide fish - 2-20 N I N ....... Sohio Alaska Petroleum Co . The existing causeway extends about 2 miles into the Beaufort Sea . Moduals for Prudhoe Bay oil production are being off-loaded at Dock Head 3 in the foreground . The flat, thaw-lake dotted landscape of the outer Arctic Coastal Plain can be seen in the background . LOW PRESSURE SEAWATER LINES & FUEL LINE ------+--+1 EXTENDED CAUSEWAY 50' BREACH WITH CLEAR SPAN BRIDGE -~ MAIN OUTFALL LINE 4.2m (14 ft) MARINE LIFE RETURN OUTFALL LINE 3.om Cro ft) (NOT TO SCALE) PROPOSED DOCK MODIFICATION & CAUSEWAY EXTENSION LOCATION PLAN PBUWaterflood Environmental Impact Statement Figure 2.5-4 2-22 I 1'1 w . 25' r-· --=--------t BULKHEAD ELEVATION 15' • 0" ROADWAY 15'-0" ROADWAY ;: I l ! . ,. ~-+-r--rl·--·;'--~'r+-~ r-r--SECTION B-8 ...-<:::: ._:.c '-C:: PILES_/ S E_ C T I 0 N A -A CLEAR-SPAN BRIDGE PBU Waterflood Environmental Impact Statement Figure 2.5-5 2-23 passage (see breaching discussion in the 11 0ther Alternatives .. section below). The proposed extension would require an estimated 688,000 m3 (900,000 yd3) of gravel covering some 11 ha (27 .2 acres) of sea bottom. The existing causeway would be widened to provide for two-way traffic of module-carrying crawlers (not essential for waterflooding) and to accommodate and protect from ice forces and storm erosion the low- pressure pipelines, fuel gas pipelines, and electrical cables needed for the Waterflood Project. Also, the present lower-profile causeway to DH 3 is very susceptible to ice override and downcutting by unusually severe storms. DH 3 would be expanded and reoriented as shown in Figure 2.5-4 to allow for the causeway extension and to permit docking of several barges simultaneously. An estimated 306,000 m3 (400,000 yd3) of gravel would be placed. Approximately 10.2 ha (26 acres) of marine and lagoon bottom would be covered by modifications to the existing causeway and DH 3. Dimensions for the proposed causeway extension and modifications are shown on Figure 2.5-6. The causeway extension would be designed to withstand maximum ice forces of 122,472 kg/m (270,000 lb/ft). The gravel mass, together with the expected formation of an ice-bound permafrost core within the causeway extension, should enable the proposed structure to withstand these forces. (This expectation is based on results of the applicant•s coring in the West Dock and on thermal analysis; Metz 1980b). During the first year or two after construction, before natural freezeback has penetrated the causeway, ice ridges could cause some embankment instability but project structures would not be affected. Basal failure of the causeway from ice push is a possibility if gravel fill is placed on fine-grained materials and until freezeback has penetrated foundation soils. The likelihood of causeway failure during project operation (3 years after initial gravel placement) is thus remote. The 5:1 side slope on either side of the causeway would provide adequate protection of system components (buried pipelines) against ice override. Calculations by Hardy Associates (1980) indicate that ice could ride up to the crest of this side slope under a reasonable set of assumed conditions and pile-up could be expected at the crest of the road surface. The applicant p 1 ans to remove this material using heavy equipment, if necessary (see Section 3.8; also Appendix J). Environmental Impact Construction of the proposed causeway extension and modifications, would require some 994,000 m3 (1,300,000 yd3) of gravel, covering an estimated 21.2 ha (52.4 acres) of benthic habitat with gravel fill. An additional 37 ha (91.4 acres) of benthic habitat could be significantly affected by direct disturbance and settling of sol ids suspended during causeway construction and by erosion of gravel from the causeway. A 50-m (164-ft) zone of disturbance was assumed based on work adjacent to the existing causeway by Grider et al. (1978). Additional gravel would be required annually to replace lost material. The sloping gravel sides 2-24 ffi w:!!: 0:..1 ::)W 0 (I) D. w w (1)-~ wD-z a:> _, ..J D.-I _, a: =:t w w O::l ::l 3: ..1(1) u. 0 a.. SECOND STAGE FILL FIRST STAGE FILL a meters (ft. ) 0.5 (1.6) 1.0 (3.3) 1.5 (4.9) ~1.95 (>6.4) b meters (ft.) meters 16.3 (53.5) 23.0 19.8 (65.0) 26.5 23.3 (76.4) 30.0 25.3 (83.0) 32.0 SECOND STAGE Fl FIRST STAGE FILL c A. EXTENDED CAUSEWAY (ft.) (75.5) (86.9) (98.4) (105.0) c b EXISTING ,USEWAY FILL f4.0m (461 ·B. EXISTING CAUSEWAY SECTION FROM EL. + 0.9m (3') SEA LEVEL EL. 0.0 SECTION FROM EXISTING SEABED PROPOSED CAUSEWAY MODIFICATIONS PBU Waterflood .Environmentar Impact Statement Figure 2.5-6 2-25 of the extended causeway would provide some add it ion a 1 and coarser substrate for benthos although agitation by wave action would limit its suitability as a habitat. The causeway extension would change wave and current regimes in the Prudhoe Bay area, which would affect sediment transport and deposit ion in nearshore environments. Changes in shore 1 ine configuration could result from a causeway extension, the most significant of which would be an elongation of Stump Island toward the causeway. Sheltered from the erosional influences of easterly waves, the eastern end of Stump ·Island could grow to the east, further constricting the gap between the island and the causeway (Appendix I). The rate at which such a closure might occur and its likelihood are unknown. However, it is assumed for impact assessment purposes (worst case) that once, toward the end of project life, the gap may close to the point that it would affect the movement of biota through the opening. Closure would depend on the discharge through that inlet versus flow through the other inlets, the spacing between inlets, and the quantity of sediment being transported. Flow velocities through the proposed causeway breach may be great enough to cause local scouring of the bed under the bridge and for a short distance at either end. The existing causeway and its proposed extension have been the subject of considerable controversy regarding effects on water quality, nutrient flow, and fish and epibenthic animal distributions and movements. Extending the existing causeway 1125-m (3700-ft) would augment hydro- graphic changes already occurring as a result of the existing causeway and is expected (based on unverified mathematical modeling results, Appendix D) to increase salinities in the east end of Simpson Lagoon (some 1670 ha, 4132 acres, of water surface) by some 3-4 parts per thousand (ppt) under conditions of a steady 10-knot wind from the north-northeast (NNE). As presented in a worst-case scenario (Section 4.2, Marine Biology), this change may reduce habitat quality for lagoon species. Flow of water through the proposed breach would not significantly alter these patterns (Appendix D). Salinity change under higher wind conditions would be similar. Lower salinity Saga- vanirktok River outflow; which is pushed westward by a NNE wind, is deflected seaward by the present dock. The proposed extension would therefore change the eastern portion of Simpson Lagoon to a more marine environment about 60 percent of the time during the open-water season, the most critical period for key species. Little detectable effect is predicted west of the Kuparuk River. Periods of NNE wind are broken up by westerly winds reversing the trend and bringing much lower salinities to the eastern port ion of the 1 agoon. The more marine influence and reduced currents may alter the competitive advantage of species and the distribution of key epibenthic species. However, because the org~nisms present in the area are relatively tolerant of rather wide variations in salinity, it is not expected that the relatively short-term variations in salinities (cf. those currently experienced) would have a singular direct and immediate impact on motile benthic fauna in the area. 2-26. F W?WF ERFGF Studies of the existing causeway have demonstrated a greater species richness and total organism density of benthic infauna on the west side of DH 3 than on the east side (Woodward-Clyde 1979, Grider et al. 1978, Spight 1979; see Figures E-1 to E-3). These patterDs show an apparent positive carrel at ion with observed changes in salinity caused by the existing causeway (Chin et al. 1979a). The effects of the existing causeway on other factors influencing benthic distributions (avail- ability of detritus, sediment size distribution, colonization rates, depth) have not been thoroughly separated. However, based on extrapo- lation of observed dock-related effects on benthos, the extension would be expected to expand the area of increased density and richness of benthos (primarily infauna) on the west side of the causeway (northwest of DH 3). It would also extend the area of decreased richness and diversity on the east side (northeast of DH 3). Extension of the causeway and possible eastward growth of Stump Island would restrict the opening through which epifauna recolonize the shallow nearshore zone. However, densities of these species, which affects their availability to predators (fish and birds), should not be significantly diminished. Distributions of epifaunal organisms would probably respond more to changes in food availability than to changes in salinity or infaunal abundance since most are motile detrjtivores or scavengers (e.g., Busdosh et al. 1979). Net gain or loss of total benthic productivity in the Prudho~ Bay area cannot be accurately predicted. However, under a reasonable worst-case scenario, ecological effects of this change to a generally more marine environment in. the eastern port ion of Simpson Lagoon may reduce its value to certain key epibenthic species and to anadromous fish that use these normally less saline areas. The causeway extension would magnify the barrier effect to nearshore migrations of fish, especially anadromous species (char, cisco, and whitefish), created by the present causeway. Inclusion of an open-span breach outside DH 3 is expected to permit fish to pass through the extension at roughly the same location that they must now pass the existing structure (see discussion under 11 Breaching Alternatives .. below). Limited tagging studies by the Alaska Department of Fish and Game ( Bendock 1977, Doxey 1977) showed that some 1 arger anadromous fish (<200 mm length) found their way around the existing causeway (past DH 3). However, these studies were inconclusive with respect to important ecological ramifications. Data do not exist to evaluate loss of reproductive potential of various races of fish due to delays or mortalities resulting from the need to migrate around this structure or the number of aborted migration efforts. Fish smaller than 200 mm would be especially vulnerable to predation 1 asses in deeper water at the end of the causeway and to intake system losses. Existing data do not allow a definitive conclusion regarding the total impact of the existing or the proposed extended causeway on fish populations in the area; therefore a worst-case scenario was developed (Section 4.2, Marin·e Biology). This analysis of the biological impacts • 2-27 suggests that large, detectable effects on local populations of inverte- brates and fish are unlikely. Conceptually, any effects could extend to bird species using the area. Under this scenario up to 2.6 and 3.5 percent of anadromous fish runs to the Colville and Sagavanirktok Rivers, respectively, might be lost due to the combined influence of the extended causeway and the intake structure. This loss, if realized, could exceed the productivity rate of populations in the area (assuming these populations do not experience density-dependent mortality) but would be unlikely to be measurable in the affected populations. Projected reductions in populations subject to the subsistence fisheries of Nuiqsut and Kaktovik would not exceed 3 percent and 1 percent, respectively. Because of the significant cultural and dietary depen- dence on subsistence resources among the native Inupiat people, a significant reduction of anadromous fish populations (primarily through cumulative effects) probably would have an adverse effect on residents of the villages of Nuiqsut and Kaktovik. This would likely take the form of increased pressure on the Eskimo to adapt to the use of modern western foods considered inferior to native fish and wildlife (Jamison et al. 1978). Reductions in subsistence activities would also weaken associated social and kinship ties (see Section 3.14). Overall effects of an extended causeway could be most significant from a cumulative standpoint. As a result of future Beaufort Sea and other coastal developments, additional causeways and water treating facilities may be constructed. Chronic or a single large oil spill may occur. These future effects on fish, benthic fauna, and ecologically related species may act in an additive or even synergistic manner to lower marine animal populations to a much lower level than that caused by any one act ion. · Seawater Intake and Treating Plant Description · A seawater treating plant would remove suspended solids and dissolved oxygen from the seawater and add heat to prevent freezing in the low- pressure pipeline system. To assure a reliable source of water during winter ice conditions, the proposed plant would be located at the water intake, in a water depth of about 3. 7 m ( 12 ft) at the end of the extension of the existing causeway {Figure 2.5-4). The combined plant would be constructed off-site as a floating platform, floated into place inside a gravel berm, ballasted to rest on a gravel pad, and ultimately removed during field abandonment. The multi-level platform would be less than 0.8 ha (2 acres) in area and would extend about 21.3 m (70 ft) above the surrounding berm surface at elevation +5.5 m {+18 ft). Approximately 420,000 m3 (550,000 yd3) of gravel would provide a total berm area above sea level of approximately 4.5 ha (11 acres). A sheet pile bulkhead would stabilize the embankment adjacent to the plant intake. 2-28 The berm protecting the seawater treating plant would be designed to withstand maximum ice forces (181,400 kg/m, 400,000 lb/ft) expected to occur in this area. The gravel mass, together with the expected formation of an ice-bonded permafrost core within the berm, should enable the proposed structure to withstand these forces. The 5:1 side slope (27-m, 90-ft, exposed slope to +5.5 m, 18 ft, elevation) and 55-m (180-ft) set-back of the seawater treating plant from the east edge of the causeway terminous should provide adequate protection of vital system components against ice override. Calculations by Hardy Associates (1980) indicate that ice could ride up to the crest of this side slope under a reasonable set of assumed conditions, and that pile-up could be expected at the crest of the protective berm (Section 3.8, also Appendix J). It is conceivable that, during an unusually severe storm, ice may pass this berm. In this event, heavy equipment would be mobilized to prevent damage to facilities and to clear the area. Process flow for the plant supplying 4.07 m3/s (64,200 gal/min, 92.4 million gal/d) to the field is shown on Figure 2.5-7. Multiple intdke openings would provide a water intake velocity of about 15 cm/s (0.5 ft/s) or less into individual intake channels. Each of these intake channe 1 s would be equipped with a state-of-the-art fish bypass system. This system would include fixed or traveling screens angled to the direction of flow. (Figures 2.5-8b, 2.5-9, see detailed description in Appendix H). Velocities would increase within the channels, downstream of the openings, as needed for proper operation of the fish bypass screening system. Organisms and debris (including ice) larger than 9.5 mm (3/8 in) and fish larger than approximately 50 -75 mm (2 - 3 in) total length would be bypassed past the angled screen arrangement. Bypassed water, debris, and organisms would be collected in individual lines from each channel (minimum 20.3-cm, 8-in inside diameter) and led to a larger (minimum 38-cm, 15-in inside diameter) outfall line. Screened seawater would be pumped through in-1 ine strainers to remove fibrous tundra particles and then heated to approximately 4.4°C (40°F) to prevent freezing in the pipelines to the injection plants. Some heated water (21°C, 70oF) may be returned to the intake reservoir to mitigate frazil and/or slush ice accumulation. The process flow would then pass through a granular media filter to remove fine particles (to <3 mg/1 total suspended sol ids) and through deaerators to remove dissolved oxygen (to <0.02 mg/1) that would corrode the pipeline system. Treated seawater would then be pumped into the low-pressure pipelines for transport to the injection plants. Chemicals would be added upstream of the filters and upstream and possibly downstream of the deaerators as shown on Figure 2.5-7 and Table 2.5-1. When filters are backwashed with untreated seawater to r.emove accumulated particles (in a regular cycle, dependent on intake water quality), the volume of residual water contained in the filters will contain biocide and coagulant and will be discharged through the main outfall. Additional coagulant also will collect in the filter media and be backwashed to the outfall line. Chemicals added down- stream of the filters would not be discharged during normal operations. 2-29 BEAUFORT SEA lb3,600,000GPD MARINE LIFE RETURN OUTFAll (002) 7,000,000. GPO MAIN OUTFALL (001) 4,200,000 GPO. lt2 Control11 ,500,000 GPO (Max.) DISPOSAL TANK 2,000,000 GPO 11,500,000 GPO (Max.) :S,200,000GPD Backwash HEAT EXCHANGERS Prerun 2,000,000 GPO CORROSION OR SCALE lllHIBITOR (Normally not used) TO WEST INJECTION PlANT 42,000,000' GPO 3,000,000 GPO FILTERS Make-up (Normally not used) Backwash 1,000,000 GPO 1,400,000 GPO TO EAST INJECTION PLANT 50,400,000 GPO PROPOSED SEA WATER TREATING PLANT PROCESS FLOW SCHEMATIC PBU Waterffood Environmental Impact Statement 2-30 Note: GPO= galld. Figure 2.5-7 bl "'0 tlJ c :E lll .... CD .., -0 0 c. m ·::J < .., 0 ::J 3 CD .... lll 3 "0 lll (') .... (J) .... lll .... CD 3 CD ::J .... "TT c2i' c: .., CD 1\) 0, I (X) SPRAY}\ <1' TROUGH TO rtg:g!] MARINE LIFE RETURN \_SCREEN ROTATION DRIVE SPROCKET FISH BUCKET FLAT SCREEN PANEL ~--#--------4~---FLOW FLOW FLOW TRASH RACK ..,. I 1 -ANGLED, FIXED TO PUMPS l OR TRAVELLING SCREEN CENTER PIER TO COLLECTION AREA :-:-:==--_.... OR MARINE LIFE RETURN ALTERNATIVE A VERTICAL TRAVELLING SCREENS (TYPICAL SIDE VIEW) ALTERNATIVE B FISH BYPASS SYSTEM WITH ANGLED SCREENS (TYPICAL PLAN VIEW) ALTERNATIVE INTAKE DESIGN CONCEPTS < w en 1-a: 0 u. :::> < w m !NT AKE & RESERVOIR SEAL GUARD OR STOP LOGS TRASH RACK ~--·INTAKE WING WALL PROPOSED INTAKE SYSTEM SHOWING MARINE LIFE BYPASS WITH EIGHT FIXED SCREENS PBU.. Waterflood Environment Impact Statement Figure 2.5-9 2-32 N I w w • TABLE 2.5-1 TYPICAL SYSTEM CHEMICAL USAGE (Estimated Average) Effective Where Added Chemical Type Concentration Use Upstream of filters Sodium Hypochlorite(a) 2.5 ppm 1928 lb/d(b) Biocide Cationic Poly-0.85 ppm Coagulant electrolyte (c) 655 lb/d Fatty Acid and( ) 0.25 ppm Anti-foam Polyglycol d 193 lb/d Upstream of deaerators Catalyzed Sodium(d) 0.9 ppm 02 Scavenger Bisulfite 694 1 b/d Downstream of deaerators Filming Amine(d} 7.0 ppm Corrosion 5398 lb/d Inhibitor Phosphate Ester(d) 7.0 ppm Scale 5398 lb/d Inhibitor Frequency Continuous Continuous Continuous During deaerator malfunction During deaerator malfunction During deaerator malfunction (a) Added upstream of the filters to establish a 0.1 ppm residual concentration at the filter feed inlet. Filter backwash feed will contain no biocide. (b) 92.4 million gal/d used to calculate lb/d. (c) Typical brands are NALCO 3332; NALCO 3364; TFL 3910 (Tretolite). (d) Added downstream of filters and thus will not be present in the outfall except during emergency displacement of both low-pressure supply lines. '•ll Only failure of the freeze protection system, requiring low-pressure line evacuation, would cause them to be discharged. Required chemicals would be either barged or trucked to the Prudhoe Bay area depending on the nature, source and bulk. They would be stored in a central warehouse and delivered to various project facilities (primarily the water treating plant) as needed. Sodium hypochlorite would be generated from seawater on site using standard commercially available equipment. Environmental Impact Dredging and filling operations required for construction of the seawater intake and treating plant and its protective berm would result in the direct loss of some 5.9 ha (14.6 acres) of productive benthic habitat in addition to that covered by causeway extension and expansion. An additional area of approximately 5 ha (12 acres) surrounding the construction zone could be affected to varying degrees by settlement of materials suspended in the water column from' construction activities or lost from the fi 11 by erosion (assuming a 50-m, 164-ft, band of potential disturbance). Operation of this type of intake under Arctic Ocean conditions has never been attempted. Design features installed to cope with the unique engineering constraints can impose biological problems not encountered in less severe climates. An example is the need to add substantial heat to control ice buildup in the system and the accompanying potential to cause thermal shock to organisms. Organisms may enter the intake channels during project operation. Most very small organisms would be entrained through the screens while 1 arger organisms would pass through the bypass system without impingement. Any intake of this volume (4.53 m3/s, 71,944 gal/min) will entrain virtually all plankton (small drifting organisms), including ichthyoplankton and some smaller juveniles in the water column, at a rate proportional to their densities in the water mass surrounding the intake. While absolute numbers lost would be high (Table 4.2-5), the densities of most organisms in Prudhoe Bay area waters should not be significantly altered (Section 4.2, Marine Biology). However, because of their attraction to structures, greater numbers in deeper, more marine waters, and the possible concentrating effect of the proposed causeway extension, juvenile marine fish species (e.g. arctic cod) may be adversely affected. Entrainment of biological material suspended in the water column (including plankton and non- living matter) has been estimated at 4.5 kg/d (10 lb/d) on an annual average basis (Table 2.5-2). This material would not be lost in an ecosystem perspective, however, since it would be discharged in the general area. The potential for entrapment and entrainment of smaller fish (less than 60-70 mm, 2.4-2.8 in), especially arctic cod, may be greatest 2-34 N ' w (..11 COMPONENT WT% TSS COAGULANT(a} BIOLOGICAL MATTER(b} Cl (c) 2 TDS, 02, N2, C0 2 (d) TOTAL RATE m3/s (gal/min} SOLIDS & COAGULANT DISCHARGE, TON/D TSS COAGULANT BIOLOGICAL MATTER FREQUENCY, CYCLES/DAY DURATION PER OCCURENCE NOTES: TABLE 2.5-2 CHARACTERIZATION OF MAIN OUTFALL PIPELINE EFFLUENT OPEN -WATER INFLUENT TSS = 150 mg/1 (Maximum Case} Daily Average Effluent 726 PPM 6 PPM 0.2 PPM 0 1.10 (17 ,325} 75.6 0.6 0.02 - - Effluent During Filter Backwash 1778 PPM 20 PPM 0.8 PPM 0 1.10 (17,325} - - - 48 9 MIN OPEN -WATER INFLUENT TSS = 25 mg/1 (Average} Daily Average Effluent 525 PPM 20 PPM 0.2 PPM 0 0.20 (3210} 10.3 0.4 0.005 - - Effluent During Filter Backwash 871 PPM 43 PPM 0.4 PPM 0 0.40 (6240} - - - 40 9 MIN UNDER -ICE INFLUENT TSS = 9 mg/1 (Average} Daily Average Effluent 92 PPM 18 PPM 0.2 PPM 0 0.18 (2800} 1.5 0.3 0.005 . . Effluent During Filter Backwash 210 PPM 55 PPM 0.6 PPM 0 0.40 (6240} - -. 24 9 MIN ~Coagulant Dosage: Open-Water Maximum: 1.5 PPM; Open-Water Average: 1.0 PPM; Under-Ice Average: 0.8 PPM. Annual Average(e} 207 PPM 18 PPM 0.2 PPM 0 0.19 (2915} 3.6 0.3 0.005 28 9 MIN (b) Biological Matter Cal'd from EST'D Dry Wt. of Samples caught in net: Open-Water Maximum: 0.05 mg/1 -505 Micron Net Used; Open-Water Average: 0.01 mg/1 -505 Micron Net Used; Under-Ice Average: 0.01 mg/1 -253 Micron Net Used (c) Biocide may normally be injected. If sodium hypochlorite is used (as assumed above}, chlorine residual in the biocide treated water will be controlled to approximately 0.1 ppm max. The backwash supply for the screens, strainers, and filters would not be chlorinated. While no free chlorine will be present, some chlorine reaction products will be (see text}. (d) (e) TDS, Oz, Nz, and COz unchanged from ambient conditions. Annual average effluent based on 9 months under ice and 3 months open water. .• ... ,, ;\ ,. )- \ -~ ;t .. during the op~n-water season when fish densities in the area are greatest. Placement of the intake inside approximately a 90° angle at the end of a causeway greatly magnifies the potential for fish encountering the intake. Fish migrating eastward along shore through Simpson Lagoon can be expected to follow the causeway generally seaward toward the intake. These were considerations in arriving at the worst- case scenario developed for fish losses. The presence of a breach in the causeway should greatly mitigate this potential impact, however. Another major factor influencing the overall magnitude of fish losses at the intake is the effectiveness of the fish (guidance) bypass and marine life return system. This system should be monitored during initial operation (Chapter 5.0) and adjustments made to optimize marine life survival, if necessary. Calculation of the exact effect of intake operation on local populations is not possible; however, the presence of the breach, the anticipated survival of more than 86 percent of the bypassed fish, and the low concentrations of entrainable ichthyoplankton in the vicinity would probably result in a low magnitude of i,mpact. This prediction does not include operation problems, such as an intake system breakdown, that could occur under the difficult arctic conditions to be encountered; however, the applicant has stated that intake system malfunctions would require shutdown of affected intake channels. Under the reasonable worst-case scenarios developed in Sect ion 4. 2, Marine Biology, a maximum population reduction of 2.6 percent of Colville and Canning River aDd 3.5 percent of Sagavanirktok River anadromous fish may occur because of the combined effects of the causeway extension and the intake. Entrainment of smaller marine fish (<60 mm, 2.4 in) could reduce the local adult populations by up to 0.1 percent annually while bypass system mortality of larger fish (>60 mm, 2.4 in) could reduce Prudhoe Bay area populations by as much as 3 percent (worst case). Although the probability of impacts of this magnitude appears low, if realized, they would represent some loss to fish predators such as seabirds and seals, and to the commercial and subsistence fisheries of the region. Because these harvesters of local marine biota are also supported to varying degrees by resources outside of the potentially affected area, reductions of these harvester populations should be less than 3 percent. Potential effect.s on the villages of Nuiqsut and Kaktovik have been summarized above under 11 Causeway Modifications ... Understanding the cumulative effects of such reductions is important for dealing with the permit issues at hand. Effects of _the existing causeway are judged to be adverse although they may not have resulted in measurable population declines. Additionally, potential future oil and gas development in the Beaufort Sea probably would involve proposals to construct additional marine causeways (Table 3.15-1). Likewise, effects simi 1 ar to those predicted herein may be expected to occur with an unknown but possibly adverse combined effect on key species. Future 2-36 treating plants for future waterflooding projects are 1 i kely to be proposed. Effects of these could also be additive or synergistic with those described. Outfall Pipelines Description Two separate effluent lines are proposed. First, an 81.3-cm (32-in) outside diameter main outfall pipeline would transport process effluents from the. seawater intake and treating plant to a diffuser located at a water depth of about 4.3 m (14 ft) approximately due north of the treating plant (Figure 2.5-4). Secondly, a minimum 38-cm (15-in) inside diameter marine life return line would transport fish and other marine life collected from smaller b~pass lines in each intake bay to an outfall located about 150m (500ft) east of the plant. The marine life return line and the 305-m (1000-ft) portion of the main line extending north from the causeway extension would be placed in trenches dredged to a depth of 1.8 m (6 ft). Dredging would be accomplished during the open-water season, probably using a clamshell dredge. Dredged material would be placed on either side of the trench. The maximum effluent flow rate in the main line would be about 1.10 m3/s (17,325 gal/min). Annual average effluent flowrate is estimated at 0.19 m3js (2915 gal/min), which reflects an annual average frequency of backwash occurrence of 28 cycles per day for a 9-min duration (Table 2.5-2). This discharge volume is comparable to that of a municipal treatment plant. The material discharged from a municipal treatment plant is, of course, quite different from the proposed discharge. Effluent chemical characteristics were estimated by the applicant based on pilot filtration tests conducted in the summer of 1979 and on periodic year-round sampling (Section 3.8). Outfall design is based on ambient (intake) water quality data for the 2.4-m (8-ft) depth under open-water conditions when suspended solids concentrations in the seawater and, h.ence in the outfall effluent, are greatest. Effluent is characterized in Table 2.5-2 for three conditions of total suspended solids concentration in the seawater from which an annual average condition is computed. The first column is based on 1 day of open-water storm conditions (TSS = 150 mg/1), the second column is based on the average open-water data (TSS = 25 mg/1), and the third column is based on the average of all under-ice data (TSS = 9 mg/1). The final column is a weighted average of 3 months of open-water average conditions and 9 months of under-ice average conditions. The diffuser, 67 m (220ft) long, would have 22, 15.2-cm (6-in) diameter no zz 1 es spaced at 3-m (10-ft) i nterv a 1 s, as described in Appendix B. The nozzles would be angled at about 20° to the horizontal and oriented parallel to the prevailing current. 2-37 Environmental Impact Construction of the marine life return line and main outfall line would temporarily destroy less mobile benthos over some 1.3 ha (3.2 acres) of seabed due to trench dredging for line placement (0.4 ha, 0.9 acre) and burial of adjacent areas by dredged materials. Epifauna would use these areas immediately following work completion and infauna would recolonize over a period of several years. Exposed areas of pipe and diffuser would be colonized by fouling organisms typical of the area . .• Outfall operation under open-water storm conditions would discharge 68,600 kg :{75.6 tons) of sol ids per day (Table 2.5-2). Current speed and wind mixing should be adequate to remove sediment from the area. If accumulatiqps do develop during slack periods, the accumulated sediment will be re~uspended and moved from the area during storms. This cycle would tend~;to reduce or eliminate less mobile infauna while organic debris in~the dis~harge likely would attract epifaunal scavengers (amphipods and isopods), that would in turn attract predatory fish to the area. Since discharged organic material would only include material already present in the vicinity (and captured by the intake), no net change in regional biological production would result; only its distribution would be altered. Under-ice discharges are considered the reasonable worst-case condition in terms of potential accumulation of solids as well as potential toxicity of effluents. Settled particles would be deposited over less than 12 ha (30 acres) under ice (Mangarella 1980). This accumulation (average depth less than 0.25 em, 0.1 in, over 12 ha) would result in some destruct ion of infauna in areas of greatest accumulation ( <1 ha) but, as in the summer, would be highly attractive to scavenging organisms and their predators. Ice act ion during breakup and wave action during the open-water season could be expected to dissipate the majority of this material each year. The winter discharge temperature, 1.1 oc (2°F) above ambient, might attract some organisms but should not have a severe impact, even if terminated abruptly (cold shock). However, a significant delay in ice formation over the diffuser would be expected and a much thinner layer of ice would develop through the winter. Mangarella (1980) estimated an under rough ice dilution factor of 50 at the edge of the A 1 ask a Department of Environmental Conservation (ADEC) mixing zone, which extends 305 m (1000 ft) from the diffuser in all directions. Within this zone, TSS concentrations would range between 2 and 15 ppm above ambient concentration under daily average discharge conditions. However, these concentrations should be within the natural variation of TSS values in the area. These values are also about the same magnitude as the standard deviation for the TSS test (Chapter 4.0). Within the mixing zone, two chemical constituents of the discharge (biocide and coagulant) are of particular concern. The applicant has 2-38 predicted that chlorine (the proposed biocide) would react with bacteria, algae, ammonia, and other oxidizable compounds and that no free chlorine would be present in the discharge. Although the free chlorine residual would be zero, there would be a combined chlorine residual. All the specific reaction products for this discharge are not known, but small amounts of chloramines and some organochlorine compounds are likely. Analysis of the long-term behavior of the reaction products of chlorine, coagulant and seawater under arctic conditions has not been made because the specific coagulant is not known. Information about three potential coagulents is provided in the NPDES permit. application. All three (Koagulan 332, Koagulan 3364, Tri-floc TFL-391) are substituted ammonia compounds. Chlorine and coagulant would be diluted rapidly during filter backwash, in the -disposal tank, and in the ADEC mixing zone. For example, chlorine would be reduced from the 2.5-ppm dose concentration to 0.02 - 2.7 parts per billion (ppb) at the edge of the ADEC mixing zone. This range is conservative because it is based solely on dilution. Reactions within the outfall 1 ine and mixing zone would reduce this range; the upper limit would be less than 2 ppb. Dilution and dispersion of chlorine compounds and sol ids are expected to prevent accumulation of significant levels in local or regional biota. However, monitoring programs (Chapter 5.0) would be instituted to document residual chlorine levels. Information pertaining to the anti-foam agent, corrosion and scale inhibitors, and oxygen scavengers is presented in the NPDES permit application. These chemicals would not be discharged on a routine basis. The excess 5-day biochemical oxygen demand (BOD) of the dis- charge would be reduced to approximately 1 mg/1 in the ADEC mixing zone. Since consumption of this BOD would occur over several days, its dilution during this time should be sufficient to prevent a reduction in dissolved oxygen concentration below 5 mg/1, even under worst-case (under-ice) conditions. The 38-cm (15-in) inside diameter marine life return line would be open-ended as shown on Figure 2.5-10. The estimated flow velocity would be at least 1.2 m/s (4 ft/s) to reduce the likelihood of fish remaining in the line. Untreated seawater with fish and other marine life bypassing the intake screens would exit from the outfall pipe at about elevation -4.6 m (-15 ft) and at an angle of 45° upwards from the horizontal. Opportunistic predators (char, sculpins) and scavengers (amphipods, isopods) would congregate around this outfall to feed on detritus and perhaps on weakened or disoriented organisms. The induced current of the outfall, and the slightly elevated temperature of the discharged water, also might attract some organisms. Although some infilling of the area around this discharge is expected, the discharge jet would maintain an adequate clearance. Some stress and mortality of discharged organisms is expected as a result of abrasion, crowding, and thermal shock. 2-39 CONCRETE WEIGHT At_~--,·~ 46cm (15")MARINE LIFE \ RETURN OUTFALL PIPELIN r----r---.--""" MEAN SEA LEVEL EL. 0.0 10' sa. 3.0m SECTION A-A NOT TO SCALE EXIST. SEABED APPROX. El.-3.7m (121 PROPOSED MARINE LIFE RETURN OUTFALL PIPELINE PBU-W_aterflood Environmental Impact Statement Figure 2.5-10 2-40 Dredging Description The proposed project would require dredging of 13,500 m3 (17,600 yd3), probably by clamshell, for placement of the treating plant gravel foundation pad. If suitable, this material would be placed as part of the fill for the protective berm. Otherwise it would be placed at some distance from the berm and would dissipate over time due to natural processes. In addition, some 5150 m3 (6740 yd3) would be dredged for setting the main discharge and the marine 1 ife return 1 ines. This material would be sidecast and allowed to refill the trench by natural processes. Environmental Impact Dredging for the proposed project waul d directly remove 0. 7 ha ( 1. 7 acres) of seabed habitat and destroy all associated infaunal organisms (area dredged for the seawater treating p 1 ant and subsequently covered by gravel, 1 ha, 2.4 acres, is not included). Dredged material place- ment and dispersion could cover an additional 3 ha (7.4 acres), assuming an average depth of deposition of 15 em (6 in). In-water sediment handling, both in the areas of dredging and disposal, would suspend solids in the water column that could affect water quality for as much as several kilometers down current (e.g., Slaney 1976). Detectable impacts on benthos due to settling of materials from this plume are expected over a much shorter distance, however, and would decrease rapidly with distance from the dredging or disposal area .. Turbidity, resulting from dredging operations, would reduce light penetration, thus reducing photosynthesis. It would also flocculate phytoplankton, decrease food availability for visual feeders, and decrease aesthetic values. Low-Pressure Pipelines Description Two insulated low-pressure pipelines are proposed to transport the treated saltwater from the treating plant to the injection plants along routes shown on Figure 2.5-1. About 2.22 m3fs (35,185 gal/min) would flow through the 102 em (40-in) diameter pipeline, about 20.9 km (13 mi) in length, to the east injection plant. About 1.85 m3/s (29,321 gal/min) would flow through a 91 em (36-in) diameter pipeline, about 16 km (10 mi) in length, to the west injection plant. Both pipelines would be buried over the initial 4 km (2 .5 mi) of their route within the proposed causeway. On shore, the pipelines would be installed as shown in Figure 2.5-11. Provision would be made for caribou passage. The 1 ines would be insulated for freeze protection and would include anchors and expansion loops t~ accommodate thermal movements. 2-41 9m (30') EXISTING PIPELINE PROPOSED PIPELINE PLAN INSTALLATION ADJACENT TO EXISTING PIPELINE' 1:. PROPOSED PIPELINE I tXISTING PIPELINE .;t ~~ ;;INGPADZ i ~L:: ~ EXISTING GRADE SECTION 9m cao·) PIPE SUPPORTS (TYP.) PROPOSED PIPELINE PLAN NEW INSTALLATION t_ PROPOSED PIPE LINE (12'-15') 4-4.5m PROPOSED PAD (TYP.) 2 1 ~ .. :. :::::: ~ ~ ~ ~ ~ ~ \ ~ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\1 SECTION PROPOSED ONSHORE PIPELINE INSTALLATION PLANS & SECTIONS PBU Waternood Environmental Impact Statement Figure 2.5-11 2-42 The eastern pipeline would follow existing roadway or pipeline routes for its entire distance. The western pipeline would follow an existing roadway to Well Pad K (Term Well A). A road extension about 3.4 km (2.1 mi) in length is proposed from Term Well A to Well Pad E (Figure 2.5-2) where existing roadways and pipelines would be followed for the remainder of the route. This road would also provide a shorter access route between the causeway and the west side of the field than currently exists. Pipes would be placed on existing racks, or on new racks constructed from existing pads where possible. Environmental Impact Since the low-pressure pipeline would follow existing roadways and pipeways over most of its length, environmental disturbance would be negligible except for the Pad K (Term Well A) to Pad E segment of the western distribution line. New pipe would be installed in a manner compatible with existing provisions for caribou passage and, except for the western segment, no new alterations of existing drainage patterns would occur. In the segment between Pad K and Pad E, some 3.4 km (2.1 mi) of new pipeline and road pad would destroy about 6.1 ha (15.1 acres) of habitat (Table 4.2-2), some of which is within a high value drained- lake basin complex. A total of 6.6 ha (16.4 acres) of wetland would be destroyed (including the pipeline from the West Dock to Pad K). Nearby habitat quality, particularly for waterfowl and shorebirds, would be degraded by noise and dust created by traffic and by alterations in natural drainage patterns. A substantial area of currently unmodified habitat would be fragmented. Although the applicant would conform to standard field practices for placing culverts, interruption of sheet flow with resultant increases and decreases in soil moisture would be inevitable. Caribou use of the area east of the proposed route apparently has been declining in recent years due to disturbance from surrounding development (Cameron 1979). However, wildlife access to the 4600-ha (11,400-acre) area between the module staging area, the CCP, Well Pad C, and Well Pad G would be somewhat restricted by the' proposed high-profile roadway (1.5 m, 5 ft) and the elevated pipeline. In summary, the overall habitat value of the modified area would be reduced along with a reduction of wetland contributions to open-water systems. Accidental rupture of the low-pressure pipeline system near the module staging area (lowest 1 ine elevation) could release up to 16,400 m3 (4.3 million gal) of heated (4.4°C, 40°F) saltwater from the east line. A rupture of the west line could release 10,650 m3 (2.8 million gal). The likelihood of such a rupture cannot be estimated. However, as a reasonable worst case, one low-pressure 1 ine rupture spilling 5000 m3 (1.3 million gal) was assumed, occurring in the line between Well Pad E and Term Well A, the area where the most sensitive habitats would be affected (the extensive drained-lake system to the northeast). The area such a spill would effect would depend on ground condition, exact location, and effectiveness of containment. Assuming a non-uniform spreading to a depth of 2 em (0.8 in), the area covered would be about 25 ha (60 acres). Because of its elevated temperature, the water would 2-43 melt its way into the existirig snow/ice layer especially near the rupture. Destruction of vegetation emerging through the ambient snow or ice layer would be expected. Areas where saltwater penetrated the tundra mat could take many years (>10) to recover. The impact of a brine spill waul d be greater at any time during the growth season when plants are actively metabolizing. Dry sites are considered to be generally more sensitive than wet sites, with moist sites having an intermediate sensitivity (Walker 1980). This is based on the premise that moist and wet sites would be subject to greater natural flushing by fresh w~ter and that graminoids (grasses), which are prevalent on moist and:;wet sites, are more tolerant to saline conditions than forbs or dwarf shrubs, which are more abundant on dry sites. H :, .. '·' Injection Plants j, ). \·'. r ~·. Description Treated seawater would be delivered to two injection plants, one on each side of the field as shown on Figure 2.5-2. The injection plants would consist of modular construction and function to increase seawater pressure to 1452 kg/cm2 (3200 lb/in2) and seawater temperature to 18° - 27oC (65° ~ 80°F). The basic process flow is shown in Figure 2.5-12. Produced water and seawater would not be mixed; however, either type of water could be transmitted through any of the high-pressure pipelines. Over the course of waterflooding, some produced water would be contri- buted by. source water initially injected from the Beaufort Sea. However, ~s individual wells begin producing excessive water they would be shut dbwn or converted to water injection wells. Chemicals present in produced water waul d be reinjected along with the water but 1 ittle concentration is expected. Environmental Impact The gas turbine pumps at each injection plant would be among the primary sources of noise and air pollution stemming from the Waterflood Project. Overall impacts from both factors (noise and air) would be minor by themselves, but would contribute to general reductions in natural habitat values in the area. Pads for the two injection plants would be placed immediately adjacent: to existing pads and would cover an additional;5.2 ha (12.9 acres), 4.2 ha (10.4 acres) of which is classi- fied as wetland. Since nearby areas are currently subjected to heavy use, the loss of natural habitat values would be of minor significance but the coverage of additional tundra would reduce the overall biologi- cal productivity of the area by a proportionate amount. Chances of a saltwater spill escaping the pad boundaries would be relatively low, but could occur if measures were not taken to direct such a spill to the emergency dump pit. However, the applicant has not as yet proposed such mitigative measures. 2-44 HIGH PRESSURE _!_ADDUCED WAT~ ____., FROM ADJACENT PRODUCTION CENTER a: w 1-c:t ~ w en INLET MANIFOLD 1 INLET TANK T BOOSTER PUMPS HEATERS INJECTION PUMPS DISCHARGE MANIFOLD I ' ' TO LOCAL WELL PADS TO INTERMEDIATE MANIFOLDS PROPOSED INJECTION PLANT PROCESS FLOW SCHEMATIC (TYP.) PBU Waterflood Environmental Impact Statement 2-45 Figure 2.5-12 High-Pressure Pipelines Description High~pressure (1452 kg/cm2, 3200 lb/in2) pipelines would transfer seawater from the injection plants to the intermediate manifolds, well pads, and individual wells. About 160 km (99 mi) of high-pressure pipeline, ranging from 15.2 -61 em (6 -24 in) in diameter, would be installed along pipeline corridors at locations shown on Figure 2.5-2. Existing gravel pads and roads would be used for pipeline construction, except for a short (335-m, 1100-ft) extension to Well Pad WF-1. One pipeline would cross the Kuparuk River. All pipelines would be installed above ground and supported on pile bents as shown on Figure 2.5-11. The pipelines would be insulated for freeze protection and include anchors and expansion loops. Provision would be made for caribou passage. The four intermediate manifolds would consist of pile-supported modules housing manifold piping and freeze protection equipment. The modules would be installed on exten- sions (less than 0.8 ha, 2 acres, in area) of the gravel pads at existing gathering centers and flow stations at the four locations shown on Figure 2.5-2. Environmental Impact Installation of the high-pressure pipeline system would have little impact on the natural environment other than covering 1.8 ha (4.5 acres) of tundra for the manifold pads. About 1.5 ha (3.7 acres) of wetland would be destroyed. Since these pads would be attached to active work areas, loss of natural habitat would be of less significance than if it were to occur in an unmodified environment. However, coverage of additional tundra would reduce overall biological productivity in the area by a proportionate amount. Some temporary increase in turbidity in the Kuparuk River is expected. The effects are considered slight. A complete rupture of a high-pressure line could release up to 1400 m3 (370,000 gal) of saltwater depending on location. Effects of saltwater spills on tundra were summarized in a preceding section, Low-Pressure Pipelines. The 1 i kel ihood of such a rupture cannot be quantified. Therefore a reasonable worst case, one rupture of a high- pressure saltwater line spilling 1400 m3, was assumed over the project life. Such a spill would cover 7 ha (17.3 acres) if spread evenly to a 2-cm (0.8-in) depth. The value of habitat thus affected would be diminished. Injection Site Facilities Description Injection site facilities would distribute incoming flow to individual injection wells, provide flow and pressure control to each well, monitor 2-46 flow to each well site and individual well, and protect the 1 ines and wells from freezing during a shutdown. Approximately 28 injection sites, 14 on each side of the field, would be located as shown in Figure 2.5-2. One new injection pad is planned and is designated WF-1. A typical layout of proposed injection site facilities with respect to existing production facilities is shown on Figures 2.5-13 and 2.5-14 for the east and west side of the field, respectively. Each site would contain a module housing control, monitoring, and freeze protection equipment, a methanol/water tank, an emergency dump pit, 15.2 or 20.3-cm (6 or 8-in) well lines, and the injection wells. The emergency dump pit at each site would be used, if needed, for emergency evacuation of high-pressure 1 ines between the intermediate manifolds and the well pads. Pits would be constructed in existing gravel pads and provided with a metal barrier to lateral flow as shown on Figures 2.5-13 and 2.5-14. Environmental Impact Typical injection sites would require approximately a 1.7-ha (4.2-acre) expansion of existing well pads. The estimated 45 ha (112 acres) of pad expansions in the field would be immediately adjacent to existing pads. Expansion of existing pads would destroy 29.7 ha (73.7 acres) of wetlands. The area of indirect disturbance may extend the area of disturbance outward from the pad modification into adjacent tundra areas because of induced permafrost melting (thermokarst effect) and surface drainage interruption. Areas of expected expansion and types of habitats affected are shown in Appendix L. Pad WF-1 with its required access road would occupy about 11.2 ha (27.8 acres) of undeveloped and relatively undisturbed ground, 11 ha (27.3 acres) of which is classified as wet 1 and. In most cases, drill pad expansions and other project facilities were sited to avoid areas of high quality habitat using the environmental planning procedure described in Appendix L. In a few cases technical restraints on siting flexibility dictated that high value areas be impacted. Proposed expansions of Drill Sites 3 and 16 would inter- fere with minor drainages if the full extent of the expansion becomes necessary. Drainage integrity would be maintained by means of culverts or stream diversions so that upstream and downstream areas would not be affected, although some high value stream habitat would be lost in the fill area. Fuel and Power Systems Description A new 30.5-cm (12-in) diameter fuel gas supply line and a new 69 KV electrical distribution line would be required from the existing CCP to the proposed seawater intake and treating plant. This powerl ine would be elevated from the CCP to the causeway base, and buried in the causeway. 2-47 0 0 PROPOSED GRAVEL PAD EXTENSION PROPOSED WELL PAD FACILITY ---"'"-~Ca. EXISTING SERVICE BUILDING----'---_, 100 METERS 500 200 FEET EXISTING GRADE EL. (VARIES) SECTION N.T.S. © METAL BARRIER AS REQUIRED EXISTING GRAVEL PAD EXISTING MANIFOLD BUILDING PROPOSED EMERGENCY DUMP PIT PROPOSED METHANOL/ WATER TANK '->---+-f WATER METAL BARRIER INJECTION WELLS PROPOSED GRAVEL PAD EXTENSION PROPOSED INJECTION WELL PAD FACILITY (TYP.)-EAST LOCATION PLAN Peu-waterfJood Environmentar Impact Statement Figure 2.5-13 2-48 EXISTING GRADE EL. (VARIES) SECTION N.T.S. PROPOSED EMERGENCY DUMP PIT EXISTING FLARE PIT METAL BARRIER 0 0 AS REQUIRED EXISTING SERVICE BUILDING PROPOSED WATER FLOOD FAC. MODULE 100 200 METERS 500 FEET 300 1000 EXISTING GRAVEL PAD METAL BARRIER PROPOSED INJECTION WELL PAD FACILITY (TYP.) -WEST LOCATION PLAN PBU Waterflood Environmental Impact Statement Figure 2.5-14 2-49 Onshore gas 1 ines would be supported above ground on pi 1 e bents con- structed parallel to the proposed eastern leg of the low-pressure seawater pipeline. Offshore fuel gas 1 ines to the proposed seawater plant would be buried during causeway modifications adjacent to low- pressure seawater pipelines. Existing fuel and electrical distribution systems would serve the injection plants. Existing electrical power systems, with the addition of substations and secondary line extensions, would serve the intermediate manifolds, well pad modules, and injection wellheads. Substations could be needed at the seawater treating plant, the CCP, and at the injection stations. Line extensions would be needed to the new drill pad (WF-1) and to the treating plant. Environmental Impact No significant environmental impact would result from construction and operation of these systems except possibly where the powerline is elevated. Many species of waterfowl and wading birds use the coastline as a migratory pathway, flying very close to the water, and would thus be vulnerable to collision with elevated wires in their path, especially during periods of low visibility. System Freeze Protection Description Water obtained from the Beaufort Sea would be at about -1.7°C (29°F) in winter and 1.1oC (34°F) in summer. Production water would enter the waterflood system at elevated temperatures (38° -60°C, 100° -140°F). The entire waterflood system would require freeze protect ion during original start-up, normal and reduced flow operations, and shutdown and restart operations. Primary freeze protect ion would be provided by adding heat to the water at the seawater treating and inject ion plants and by insulating pipelines. Backup provisions to maintain a sufficient flow of heated water include conversion of flow in pipelines downstream of the injection plants from seawater to produced water, or vice versa, and circulation of heated water where parallel lines exist. Emergency power supplies and diesel fuel backup would be provided. In the event all methods of freeze protection should fail for an extended period, all or part of the waterflood pipeline system could be evacuated by displacing the water with natural gas. Water in the low-pressure piping would be displaced toward the seawater treating plant. If only one side of the field were inoperative, water could be moved to the other side. In the un 1 ike 1 y event that both sides were inoperative, water would be displaced to the treating plant and discharged through the main outfall line. This measure would not be instituted until water temperature in the 1 ine was approaching the freezing point. Time from loss of flow to pipeline freezing (66 hours, assuming line temperature at 4.4°C, 40°F, and ambient temperature at 2-50 -48°C, -55°F) should allow for additional reaction of biocide residual in the water discharged. The anti-foam agent should be almost totally consumed in the deaerators. Anti-scale or anti-corrosion chemicals would not be present unless the deaeration system malfunctioned prior to failure of all other freeze protection measures. For a reasonable worst-case analysis, one emergency discharge of the low-pressure 1 ine contents could occur over the life of the project and one planned discharge could occur as part of project abandonment. High:-pressure pipelines would be displaced either down the well or to emergency dump pits. For start-up, pipelines waul d be preheated with warmed gas. A heated methanol/water start-up batch waul d warm the well 1 ines and existing wells at injection well pads. All gas used for displacement or warm-up would be captured in the existing oil production systems. Environmental Impact Operation of the freeze protect ion system waul d require a substantial amount of heat input at the intake and treating plant and in the low and high-pressure piping. This energy would be supplied from the field fuel gas system, some of it in the form of otherwise wasted heat from the injection pump turbine drivers. In the unlikely event that evacuation of both low-pressure 1 ines is required, a total of 27,200 m3 (7 million gal) of deaerated, chemically treated seawater would be discharged through the main outfall line. Under open-water conditions this would be rapidly diluted in the ambient water and aerated by surface contact. Tax ic conditions, due primarily to biocide (chlorine) residuals in the pipe, could stress or kill animals in the immediate vicinity. While almost all effects would be temporary, some residuals could persist in the environment. Extremely cold conditions, necessary (along with freeze protection system failure) to force line evacuation, are more likely during the winter. Under-ice dis charge of the low-pressure 1 ine contents (reasonable worst case) waul d have more serious ramifications since circulation is limited and air contact is eliminated. Field gas pressure would allow evacuation in about 4 - 5 hours, thus releasing a large slug of water with relatively little dilution available. As a mitigation measure, the treatment plant backwash system would provide raw seawater dilution flow of at least 0.6 m3Js (9510 g_al/min). Total discharge would be extended for up to 24 hours (0.3 m-3/s, 4755 gal/min, from the low-pressure line). Motile species, such as fish, should be able to avoid areas of low dissolved oxygen or detrimental chemical concentrations. Other forms, such as benthic infauna, would be unable to avoid unfavorable conditions. However, lowered dissolved oxygen should not create a problem for these species for two reasons: the relatively brief duration of exposure and the low oxygen consumption rates these animals assume under cold water conditions. Few data are available to evaluate thermal shock effects on arctic fauna in very cold 2-51 seawater, but temperatures increases of less than 1o -2°C are judged to be within their zone of tolerance. Buoyancy of the slightly warmer water could reduce exposure risk to benthos while increasing exposure risk for epontic (under-ice) species. As is typical with oil wells in the Prudhoe Bay field, some permafrost melting and ground surface subsidence is likely to occur within the immediate vicinity (2-m, 7-ft diameter) of waterflood wells over a period of years. Air Emissions ' ,, < New atmospheric emission sources would be the t~n gas-fired heaters at the seawater treating and inject ion plants an~ the nine gas turbine units at the injection plants. The estimated ~:ir emissions from these sources are summarized in Table 2.5-3. The numli,er of heaters shown may be increased in the final design to allow heating of the injection water to 2rc (80°F) to prevent formation of precipitates. Because of the generally excellent circulation in the area, no significant adverse impacts are expected to occur to humans, vegetation, animals, or material . Solid Waste Project construction and operation would generate a variety of solid wastes (some of them carried in a 1 iquid medium) that will require disposal in the study area. Solid waste generated during construction would be collected and sold as scrap, disposed of in existing or proposed commercial disposal facilities, or transported from the area. According to Bateman (1979) and FERC {1979), sufficient 1 andfill capacity is avail able to handle solid wastes from this and other proposed projects at Prudhoe Bay. Drilling fluids and cuttings from drilling water injection and addi- tional production wells would be disposed of in accordance with standard ~ field practice. Used mud would be placed in reserve pits at each drill pad. After sett 1 ing of sol1ds the supernatant water would be pumped into wells, used to control road dust, or reused to make up new drilling muds. The dried mud cake would be covered with gravel. Solid wastes collected from intake water in the seawater treating plant would be disposed of with 1 iquid effluent in the outfall system as described above. The only ,other solid waste generated during system operation would result from treatment of water from well pad emergency dump pits at the existing liquid waste disposal facilities. Solid wastes generated by operating personnel would be disposed of using existing facilities at Prudhoe Bay. -- 2-52 N I (J"J w TABLE 2.5-3 PRUDHOE BAY UNIT WATERFLOOD PROJECT ESTIMATED AIR EMISSIONS SUMMARY TABLE -~ SEAWATER TREATING PLANT Fired Heater Stack Gas Number of lJnits 6 Size per unit 100 million BTU/hr(f) Composition Vol %' N2 72.0 02 2.s(a) C02 9.8 co(b) 20 PPM NOx 80 PPM(b) so2 0.6 PPM H 0 15.7 Hydrocarbons(b) 5 PPM TOTAL 100.0 Particulates(b) 15 PPMW Flowrate, acfm per unit 52,000 Temperature, • F 600( d) Continuous or Intermittent c Frequency - NOTES: (a) Based on 15 percent excess air (b) Based on EPA emission factors, AP-42 (c) Based on NSPS gas turbines (tons/year) (8) (83) (0.3) (1.4) (d) Heater efficiency is 85 percent based on fuel LHV (e) Assumes heat recovery unit installed on gas turbine (f) Heater duties are BTU inputs based on fuel LHV Gas Turbine Stack Gas 9 16,000 HP 77.1 15.9 2.7 40 PPM (77) 150 PPM(c) (413) 0.1 PPM (0.3) 4.3 •. lO·PPM (14) 100.0 N.A. 210,000 300-35o(c) c - INJECT! ON PLANTS (g) The number of units and resulting emissions may be increased to raise injection temperature. ~I Fired Heat1r) Stack Gas g i I 4 25 million BTU/hr(f) 72.0 2.s(a) 9.8 20 PPM (2) I 80 PPM(b) (21) 0.6 PPM (0.1) 15.7 5 PPM (0.4) 100.0 15 PPMW 13,000 6oo(d) I Emergency backup heating --··- Schedules, Construction Method, and Transportation The proposed schedule and construction methods for the waterflood facilities are provided in Appendix· B. Total project schedule and construction requirements pertinent to evaluating overall environmental impact of the project are provided in this section. The applicant•s current project schedule is provided in Figure 2~5-15. Project construction would extend over a 4-year period, from mid-1981 to mid-1985. Start-up of project Increment 1 wbuld be in mid-1984 with Increment 2 start-up occurring about one year later. Increment 2 consists of the additional facilities required to increase the.\field seawater injection capacity from 2.78 -4.07 m3Js (43,750 -G4,200 ga 1 /min). U 1.: f, The overall sequence to project construction is.to process and fabticate all major facilities in modules off-site in parallel with the inst:alla- tion of gravel, piling, and pipelines on the project site. The modules would be brought in by sea during the 1983 and 1984 summer seasons, installed at the prepared sites, and connected to the newly installed pipeline system. The type and number of modules are as follows: 1 seawater intake and treating plant 15 modules for the two injection plants 4 modules for the four intermediate manifolds 56 modules for the 28 injection well ~sites 8 tank skids An estimated 43 modules would be brought to the site in the summer of 1983, and the remaining 33 modules in the summer of 1984 for Increment 2. Excepting the seawater intake and treating :plant, all modules would be unloaded at DH 3 and transported to the module staging area at the base of the causeway. Transport to installation sites would be by crawler or rubber-tired vehicles using gravel roads. This schedule of material movement to Prudhoe Bay is compatible with other logistical needs for the area including Kuparuk field development, gas conditioning plant construction, and gas line construction. Pro- posed modifications to DH 3 and the existing causeway would allow 6-8 barges to unload simultaneously and two-way traffic on the causeway, thus greatly increasing throughput capacity of the dockhead and cause- way. The mod ifi.cat ions proposed take into account transport at ion needs for the other developments mentioned above. Haul road traffic and air traffic would increase somewhat, but not significantly. Therefore, no logistics conflicts with other planned or potential projects would ' 2-54. N I 01 01 "tJ m c ~ £1) -(1) ~ -0 0 c. m ~ < -· ~ 0 ~ 3 (1) ~ -£1) - 3 'C £1) 0 -(J) -I» -(1) 3 (1) ~ - ., <0' c: ~ (1) 1\) en I ..... 01 ACTIVITY DESCRIPT.ION 1 SEAWATER TREATING PLANT PLATFORM PRELIMINARY DESIGN BECHTEL DETAIL DESIGN FABRICATOR DESIGN PROCURE EQUIP. AND MATERIAL FABRICATE PLATFORM TOW PLATFORM TO NORTH SLOPE OFFSHORE GRAVEL a PIPELINES (CAUSEWAY a SUBMARINE) PRELIMINARY DESIGN BECHTEL DETAIL DESIGN . MATERIAL PROCUREMENT BID a COMMIT-ISLAND CONSTRUCTIO -CAUSEWAY CONSTRUCTION MOBILIZE FOR-ISLAND CONSTRUCTION -CAUSEWAY CONSTRUCTION CONSTRUCTION-ISLAND -CAUSEWAY BID a COMMIT-PIPELINE CONSTRUCTION MOBILIZE PIPELINE CONTRACTOR INSULATE a WEIGHT COAT PIPE LAY PIPELINE a TEST FLUSH a CLEAN PIPLINE GRAVEL ISLAND MODULES PRELIMINARY DESIGN DETAIL DESIGN PROCURE EQUIP. & MATERIAL FABRICATE MODULE TOW MODULES TO NORTH SLOPE NORTH SLOPE INSTALLATION INSTALL PLATFORM INSTALL MODULES HOOK-UP a CHECK OUT SYSTEM MECHANICAL COMPLETION 8 PRECOMMISSIONING 1980 1981 1982 1983 2 3 4 1 .2 3 4 1 2 3 4 1 2 3 4 . -· --· --to . . .:.-- ... __ --. : ·--. • Pill! . ~ . . . . . ~-. ----·-·· . . . . -· . . . . . . . . . . . ·~ . . . . . . . -~ : I"' . . .. .. • -!I ~ __ , ·~ .. ... _ ------.. --... .. . . ----. -~~ -.D£E Ll a. ffsT • . .. .. .. :. .. ·--· . : ;.._ --... _ --.. . . . _.:. ~- ... _ ---· .__ ----... _ --. ··-------1.· . • .i. l.i--. . .. ·-· . .. .. . . :.. . =--,.... PROJECT SCHEDULE PRUDHOE BAY UNIT WA TERFLOOD PROJECT '\, 1984 1985 1 2 3 4 1 2 3 4 . ·' . . . . . . . . . : • . . . . . -. . : . . . :· . . . . • 1-. . . ~: . . . . . ,_ . . . -. -· .. LEGEND : . -CAUSEWAY EXTENSION :..-(PROPOSED) . ,.;., ·-· . . •••• GRAVEL ISLAND SCHEDULE . . ._ __ . . :..,_. &.. • •• "'" • CRITICAL PATHS ~ be anticipated. If construction of the Waterflood Project coincides with other major developments in the Prudhoe Bay area, such traffic would be significantly greater than at present. The cumulative effect of increased transportation relates primarily to increased sea traffic and the increased chance for marine accidents, spills of fuel and other compounds, increased noise and turbidity, and disturbance around docking areas. This would represent a short-term decrease in quality around these areas. Gravel Use Description Total project qravel requirements are estimated at 2.5 million m3 (3.3 million yd'J). A summary of estimated requirements is provided in Table 2.5-4 for each facility and year of scheduled gravel placement. Total anticipated requirements for other Prudhoe Bay area activities are shown in Table 3.15-1. The highest rate of placement would be 864,000 m3 (1.13 million yd3) in the Beaufort Sea during the summer of 1981. The largest annual volume, 1.16 million m3 (1.5 million yd3), would be placed during 1982. Maintenance requirements for these facilities are estimated to add some 50,000 -100,000 m3 (65,000 - 130,000 yd3) annually. Gravel is expected to be extracted from existing on-land mines that would be expanded to provide for project needs. Locations of these and possible additional sources are shown in Figure 3.4-L The estimated additional extractable volume and expected direction of expansion of these existing sources are provided in Table 2.5-5. Based on these figures, the proposed Waterflood Project would use about 25 percent of these minimum estimated reserves. Predicted future gravel requirements are estimated at 31 million m3 (41 million yd3; Table 3.15-1). It is apparent that future oil and gas development will require the opening of new gravel sources either on land or at sea. Environmental Impact The location and manner of gravel extraction needed for Prudhoe Bay development has been the source of some controversy over the last decade. Current practices prohibit extraction from active floodplains but have permitted use of recently active riverine deposits naturally or artificially isolated from their parent streams. Such sites (Kuparuk Dead Arm, 11 Put Oxbows .. , and 11 Sag C11 ) supply the majority of current and proposed gravel requirements in the Prudhoe Bay area. Environmental impacts include direct loss of tundra habitats including wetland, noise from heavy equipment and blasting (only needed when ground is frozen), and effects on local drainage patterns. Removal of the required 2.5 million m3 (3.3 million yd3) of gravel for this project could alter some 25.2 ha (62.3 acres) of terrestrial or wetlands habitat (assuming extraction to an average depth of 10 m, 33 ft). Major habitats affected from 1 imited expansion of the four sites now in use 2-56 f'"" ";·:;. TABLE 2.5-4 ESTIMATED GRAVEL REQUIREMENT SUMMARY PRUDHOE BAY UNIT WATERFLOOD PROJECT(a) ·, Gravel Year !Facility (1000 m3) (1000 yd3) 1981 1982 -'\ •.;. Road -Staging~~Area to West Inject ion Plant l• Seawater Treat(ing Plant Causeway Exten~ion DH 3 and Causeway Modifications Causeway Extension Causeway Modification Pipeline Construction Pad Inject ion Plants Intermediate M ani fa 1 ds Total 1981 Well Pad Extension and Emergency Pits Total 1982 1983 · Seawater Treating Plant Well Pad Expansion and Emergency Pits Total 1983 Waterflood Total 1980-1983 99 191 459 115 864 229 191 84 92 31 535 1162 229 268 497 2523 130 250 600 150 1130 300 250 110 120 40 700 -- 1520 300 350 650 3300 (a) Initial actions only; does not include maintenance which could add another 50,000 -100,000 m3/yr. · 2-57 Site Sag C Put Oxbows North South Kuparuk Dead Arm TABLE 2.5-5 EXISTING GRAVEL SOURCES IN THE PRUDHOE BAY AREA(a) Remaining Extractable Volume 765,000 m3 (1,000,000 yd3) 2,290,000 -6,100,000 m3 (3,000,000 -8,000,000 yd3) 3,825,000 m3 (5,000,000 yd3) 2,290,000 m3 (3,000,000 yd3) Most Likely Direction of Expansion East or West North Northeast and Southwest North (down channel) (a) Estimated or known reserves from 1981 -1985 gravel plan; data provided by ARCO Oil & Gas Company and Sohio Alaska Petroleum Company. 2-58 would be predominantly relatively low value moist tundra, sparsely vegetated alluvium, and previously disturbed areas. However, because of the great quantities of grave 1 needed for future projects (Sect ion 3.15), mining sites likely will continue to be controversial. The cumulative effect of the proposed Waterflood Project would be to require future projects to develop new sources earlier. (Refer to Section 4.1 for a more complete discussion of cumulative effects.) Labor, Supplies, and Services Total manpower requirements for construct ion and operation of Prudhoe Bay facilities are always larger than the number of workers actually at the worksite at a particular time. On the Waterflood Project, the construction workforce is expected to work a typical schedule of 4 weeks on and 1 week off (rot at ion factor of 1. 25) . For craft 1 abor, however, the typical schedule is 8 weeks working and 1-2 weeks off. Typical shifts are 10 or 12 hours. Figure 2.5-16 shows the estimated on-site manpower requirements by quarter. Total manpower requirements would be approximately 25 percent higher because of the rotation factor. Thus, total peak employment is estimated to be approximately 900. Note that this is an estimate of field labor (about 20 percent of total), supervisory personnel and construct ion management required to install the various components of the project (about 30 percent of the total). It does not include offsite engineering, fabrication, or corporate management. Also, this estimate does not include project owners• management and representatives or government inspectors and environmental monitors in the field. The main crafts required by the project are pipe welders (1 arge and small diameter), pipefitters, radiographers, equipment operators and drivers, electricians, and laborers. Figure 2.5-16 represents a total of approximately 4.5 mill ion manhours of 1 abor. Currently the average direct labor for all crafts is approximately $20/hr. If overhead and premium pay are included, the total cost for craft labor is near $35/hr. Operation of the waterflood facilities is expected to require 60 -70 operator positions and 20 -25 maintenance positions. With approxi- mately four people required for each operator position (two 12-hour shifts, two rotations) and two people for each maintenance position, the total work force would be 280 -330. The applicant intends to institute their usual practices and policies to encourage minority business participations in this project. The applicant has indicated that existing informal recruiting of North Slope Borough residents would be continued and expanded. Details relating to expansion plans are not available. The applicant has indicated the intention to actively recruit for all job vacancies, working in concert with the A 1 ask a Department of Labor. They have further stated they would fill all openings with Alaska residents to the extent possible. It is important to note, however, that most local Inupiat employment 2-59 YEAR 1981 1982 1983 1984 1985 QTR. 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 1,300- 1,200 1,100 - 1,000 ...J w 900-z z 0 (/) a: 800 w 0. u. 0 a: 700- w m ::::E :;) 600 z •••••••••••• ••••••••••••• •••••••••••••• '·············~ 500- 400 300- 200 ············· ·••••••••••••• ••••••••••••• ·••••••••••••• ·············~············· •••••••••••• ••••••••••••• ·······•········••• 100- 0 Source: Prudhoe Bay Unit Waterflood Task Force. ESTIMATED ON-SITE CONSTRUCTION MANPOWER REQUIREMENTS QUARTERLY AVERAGE PBU Waterflood Environmental Impact Statement Figure 2.5-16 2-60 would likely result from the North Slope Borough and native· organi- zations and not directly through industry. A variety of goods and services would be purchased in Alaska, depending on availability. The applicant plans to use Alaska suppliers and distributors where possible. A number of services such as surveying, catering, and typical oil field service needs are available from service companies at Prudhoe Bay. It is general practice that during construction, most of the installation contracts require the installa- tion contractor to furnish his own supplies, so no direct purchases would be made for these contracts. No estimate is available of the value of various types of purchases or t;heir origin. Project construction and operation wpuld have obvious stimulating effects on the economies of the North Slope Borough, Fairbanks, Anchorage and cons~ruction centers ~n the Lower 48 where project components were constructed. 1: Project Abandonment No specific abandonment plans have been developed by the applicant. However, abandonment of all PBU facilities will comply with all applicable local, State and Federal laws and regulations. ALTERNATIVES OTHER THAN THE PROPOSED PROJECT Numerous alternatives were deve 1 oped during the course of the app 1 i- cant • s planning, before the need for an EIS was determined. These alternatives and ot.hers generated by public and agency analyses were assessed for pract9tality based on environmental, engineering, and economic considerations. The following presents those alternatives that were given detailed analysis~ Causeway Alternatives Alternatives to the: causeway extension 'include several other intake location concepts. Engineering considerations require an intake opening 1.5 m (5 ft) high. A minimum of 0.3 m (1 ft) of clearance is required above the intake to reduce entrainment of slush or rubble ice under the solid ice cover. To reduce chances of entraining fine bottom sediments, an additional 0.3 m is required between' the seafloor and the intake opening; thus, a minimum 3.7-m (12-ft) wat~r depth is required (allowing 0.3 m for buoyancy of the ice). However, water depth at the end of DH 3 is only approximately 2.4 m (8 ft), of which up to 2.1 m (7 ft) is frozen in winter. Situating the intake at DH 3 would require dredging a hole 1.3 -1.5 m (4.2 -4.9 ft) deep on the shore side of DH 3 and incorporating a dredged communication channel from the intake to the 3.7-m contour. The alternative to an intake on the causeway is to situate the intake at the appropriate depth (3.7 m, 12 ft) or deeper. This opens two 2-61 variations: (a) A remote intake, or {b) the intake and treating plant both at the 3.7-m depth. Locating the ~ntake in deeper water (e.g. 7.3 m, 24ft) would result in improved intake water quality and thus, less discharge of solids. However, significant amounts of suspended sol ids are present even at 7.3 m. Greater costs associated with longer intake pipes as well as engineering problems (remote screens, greater ice forces, head loss in the piping, etc) led to the rejection of this alternative. It would not have the adverse effects re 1 ated to the proposed causeway extension, however. Initially, the applicant preferred the treating plant remain no farther offshore than the end of DH 3, suggesting several alternatives of "remote intake" design. Bottom-founded structures above the sea-bed, but affording protect ion of the remote intake from ice keel scoring, did not prove capable of resisting ice keels, rubble ice formation, or ice plugging. A later version of this design is depicted in Figure 2.5-17. Significant technical problems exist for achieving reliable, remotely-controlled heating and screening systems. Thus, it would be necessary to eliminate screening and heating at the intake to prevent frazil ice blockage. Alternatively, a feasible concept must include an intake located such that it can be manned and maintained continuously, if needed, to ensure reliable operation. A manned island for intake alone (i.e., the treating plant would be on the causeway) would be nearly as large as that described under Alternative B {below) to protect the faci 1 ities from ice forces, ice override, and to allow for reliable operation. Therefore, the only feasible alternatives appear to be those whereby the intake is "integral" with the seawater treating plant. The following alternative integral intake configurations were considered in this evaluation: Alternative A--The applicant's proposed alternative discussed above (see Figure 2.5-4). Alternative B --Intake and water treating plant located on a 5.3-ha (13-acre) gravel island at the 3.7-m contour (Figure 2.5-18). Alternative C --Intake and water treating plant at DH 3 with a dredged communication channel to 3.7 m (Figure 2.5-19). A minor reorientation of the direction of the causeway extension, or in the placement of the gravel island (e.g. Figures 2.5-4, 2.5-18), might shorten the distance from DH 3 to the 3.7-m contour. If this were done (based on the results of more detailed bathymetry) it caul d slightly reduce quantities of gravel needed, area of bottom covered (Alternative A), and the amount of dredging required {Alternative B). Such a --• 2-62 . 10.4m (34') DIA. INTAKE LINE 0 INTAKE PORT PLAN STRUCTURE FILLED WITH SAND 61 m (200') DIA. SECTION A-A N.T.S, (16') 4.9m ALTERNATIVE REMOTE SEAWATER INTAKE STRUCTURES PLAN & SECTION -(TYPICAL) PBU Waterflood Environmental Impact Statement Figure 2.5-17 2-63 MAIN OUTFALL HELIPORT MARINE LIFE RETURN~----LA"' GENERATORS DIESE-L STORAGE INTAKE BURIED LOW PRESSURE SEAWATER, & FUEL LINES--------11 EXISTING DH 3 ----- MODIFIED DOCKHEAD (NOT TO SCALE) GRAVEL ISLAND AL T"ERNA TIVE (B) PBU Waterflood Environmental Impact Statement Figure 2.5-18 2-64 ~~-£ 61m (200') WIDE ACCESS CHANNEL BOTTOM ELEVATION -3.7m Ct2') a.om CtO'J EXISTING DH 3 MARINE LIFE RETURN OUTFALL LINE EXPANDED CAUSEWAY (NOT TO SCALE) MAIN OUTFALL LINE SEAWATER TREATING PLANT AT DH 3 ALTERNATIVE C PBU Waterflood Environmental Impact Statement 2-65 Figure 2.5-19 readjustment would not significantly alter the effects of the extension on marine circulation or biota. Alternative B -Gravel Island Under this alternative the intake and water treating plant would be located on a gravel island constructed some 1125 m north of DH 3 in 3.7 m of water (Figure 2.5-18). The island would have a top elevation of 5.5 m (18ft) with a surface area of about 5.3 ha (13 acres). The water treating plant would be set back 55 m (180ft) from the east side, as in the proposed alternative, to accommodate potential ice override. The intake would be located on the south side of the island where the shoulders of the island would extend about 12m (40ft) to provide ice protection to the intake grating. Intake and water treating plant design and function would be as described for the proposed alternative. Treated water would be returned to DH 3 via low-pressure pipelines laid in a dredged channel a minimum of 3.7 m below mean sea level or 0.9 m (3ft) below the seabed for ice protection. The marine life return line would discharge off the center of the west side of the island and the main discharge would be located about 300 m (1000 ft) north of the island. Under this alternative, the existing causeway and DH 3 would be modified and expanded as described for the proposed alternative, except that powerl ines waul d not be required since power waul d be generated on site. Unverified, two-dimensional modeling studies (Appendix D) indicated the island would have a relatively minor and localized effect on water circulation and water patterns within a radius of about 1-1.4 km (0.6-0.9 mi). However, consideration of the three-dimensional aspects of circulation could result in greater water quality changes 11 downstream 11 of the island than indicated by the model due to upwelling of more marine subsurface waters. In either case, no significant impact would be felt near or inside the inner barrier island chain (Simpson Lagoon) and no significant biological changes would result. Gravel for island construction and annual maintenance would be trans- ported via ice road from on-land sites and result in significantly less total bottom area coverage than the proposed alternative. Alter- natively, suitable fill might be available from subsea deposits north of Stump Island (AEIDC 1980). A temporary loss of infauna would occur due to dredging and burial along the pipeline route between DH 3 and the island, as well as subsea dredging areas. Entrainment of planktonic organisms (considered to be proportional to the volume of water removed) would not differ from that in the proposed intake configuration while the chances of bypass system mortality of smaller anadromous fish would be reduced significantly. Under the proposed alternative, fish migrating generally eastward can be expected to move north along the existing causeway and be lead directly to the 2-66 intake vicinity unless they pass through the breach provided. Under the gravel island alternative, these fish could pass freely to the east side of DH 3 without encountering the intake. A variation on this alternative would be to construct the island essentially as described but to connect it to DH 3 via an elevated trestle or causeway constructed on pilings or piers. This would provide logistical access similar to that described for the proposed alternative while allowing essentially free circulation of water and biota north of DH 3. However, the cost of bui 1 ding such a structure that would withstand expected ice forces is considered prohibitive. The gravel island alternative (without the trestle) would require less gravel to construct but have a higher initial construction cost than the proposed alternative {Table 2.5-6). Annual operating and maintenance {O+M) costs would be greater because of increased facilities and support personnel, and the transportation problem imposed. Reli- ability of the intake system would be generally high except for somewhat greater vulnerability to ice gouging of the treated seawater, and fuel gas lines between DH 3 and the island. However, adequate designs could reduce this vulnerability. More complex maintenace and access problems could reduce reliability below that of the proposed alternative during periods of difficult access conditions. This would tend to increase the risk to worker safety. This alternative represents the least risk to anadromous and marine fish and would not have any adverse ecological effects on Simpson Lagoon as do all a 1 tern at ives re 1 a ted to extending the causeway. This approach also avoids most cumulative adverse effects to the marine environment incurred by the other approaches. On-island power gener- ation facilities would place a new noise and atmospheric emission source offshore. Fuel storage and handling would increase the risk of oil spillage. While the gravel island approach represents the least risk to environmental resources, it also represents construction, maintenance, and operation costs that are greater than the ~applicant's proposed alternative. This alternative also would have a slightly less opera- tional reliability than causeway extension alternatives and be slightly more hazardous because of its isolation from the land. It is likely that implementation of this alternative would result in a 1-year delay of project start-up (Figure 2.5-15). Alternative C -Dredged Channel Under this alternative the integral intake and treating plant would be located on an expansion of DH 3 (Figure 2.5-19). To provide the requisite depth for year-round operation, a shallow basin (to 3.7 m, 12 ft) would be dredged around the intake and a connecting channel (60 m, 200 ft, bottom width) dredged northward to the 3.7-m isobath. The general layout of facilities, and the design and function of the intake and water treating facilities would be as for the proposed 2-67 TABLE 2.5-6 COMPARISON OF ALTERNATIVE INTAKE CONFIGURATIONs(a) FACTOR Estimated cost (1980$) Initial Annual O&M (Total) Reliability Access A (proposed) Base ($2 billion) Base ($60-70 million) High Trucks -buses Total gravel requirement (x 1000) (specific to intake and treating plant configuration) -m3 (yd3) Initial 1100 (1438) Annual maintenance Total dredging required -m3 (yd3) Initial 18,650 (24,340) Annual (to be determined) Bottom ar~a)disturbed by dredging(e -ha (acres) Initial <1 (2.5) Annual None Bottom area covered with gravel fill -ha (acres) 27.1 (67) Intake water quality problems Moderate Effect on local circulation and water quality Significant Effect on fish migration Moderate Impingement risk Moderate Personnel positions(f) Operation Maintenance 60-70 20-25 B (island) Base+ $66 million Base+ $6 million Medium-high Helicopter-boat(b) 534 (715) 39,000 (51,000)(C) None 3.1 (8) None 16.1 ( 40) Moderate None None Low 6-8 Additional (a) Rationale behind relative impact ranking is provided in the text. c (dredged channel) Base Base+ $10-20 million Low Trucks-buses 262 (342) 197,850 (258,800) 83,316 (109,000)(d) 16.3 ( 40) 14.7 (36) 12.4 (31) Greater Low Low Moderate 60-70 20-27 (b) In winter, an ice road could also be constructed for access by trucks or buses. (c) Assuming main outfall is located to the north of island and marine life return line to the west of island. (d) Assuming 50 percent of channel volume must be dredged each year. (e) Dredged area only-does not include areas covered by disposal of dredged material. (f) Approximately four people are required to fill an operator position (two 12-hr shifts; two rotations). Less than four people are required to fill a maintenance position due to lower staffing on the night shift. 2-68 alternative except that the main outfall line would extend about 1220 m (4000 ft) to the northwest. The major drawback to this alternative is the probable need for annual maintenance dredging and the probable difficulty in accomplishing maintenance dredging during certain times of the year. Sediments moved by fall storms occurring immediately prior to freeze-up could fill the channel to a point where flow to the intake would be impaired by ice in late winter. Under such conditions redredging would not be possible until the following open-water period. Thus, this alternative ranks lowest in terms of reliability (Table 2.5-6). A variation on this alternative (C-1) would place the intake and water treating facility on the end of a short causeway extension with the intake opening northward at the 2.4-m (8-ft) contour (Figure 2.5-20). Sediments moved by late fall storms would be less likely to completely block the channel and a nominal 0.6-m (2-ft) 11 Window 11 between the ice and the bottom could be expected. However, design of the intake screening system would be greatly complicated by the need to design to withstand ice forces up to 181,440 kg/m vs 122,472 kg/m (400,000 lb/ft vs 270,000 lb/ft) and would result in a more expensive intake system. Alternative C has a comparable initial cost and lower gravel require- ment than the proposed alternative (Table 2.5-6). Despite a substan- tially greater amount of annual dredging, the annual operation and maintenance costs do not vary significantly from those of the proposed alternative. Less bottom area would be covered with permanent fill, but benthos would be disrupted along the channel with each maintenance dredging. The quality of water entering the plant could be significantly poorer due to higher sediment loads in nearshore waters and thus, increase the quantity of discharged solids. Vessel activities at DH 3 could also reduce intake water quality. Alternative C would have a relatively minor impact on existing circulation patterns, except in providing a channel for saltwater intrusion into nearshore waters and a channel for brine drainage during freeze-up and subsequent ice growth. Alternative C-1 would accentuate slightly the impacts due to DH 3 on water circula- tion and quality that have already been reported (Spight 1979). Neither alternative (C or C-1) would adversely affect Simpson Lagoon biota.· If migrating fish are maintaining contact with the bottom at a certain depth, this configuration would deprive them of that orientation as there would be no shallow water route (<3.7 m, 12ft) past the intake. This could cause fish to veer shoreward and bring them into the immedi- ate vicinity of the intake. Colder, more saline, offshore waters in the channel could also affect the orientation of fish migrating in response to chemical stimuli associated with a specific water mass unless the estuarine surface layer remained relatively intact over this marine intrusion. 2-69 SEAWATER TREATING PLANT-+--o~ MARINE LIFE RETURN OUTFALL LINE EXPANDED CAUSEWAY 3.7m (12•) ~--ct. 61 m (200'). WIDE ACCESS CHANNEL BOTTOM ELEV.-3.7m (12•) a.om Cto•) (NOT TO SCALE) DOCK MODIFICATION & CAUSEWAY EXTENSION LOCATION PLAN (ALTERNATIVE C1) PBU--Waterflood Environmental Impact Statement Figure 2.5-· 20 2-70 Alternative Breaching Schemes Justification and Benefits The permits granted to the PBU operators by the State of A 1 ask a and the Corps of Engineers authorizing emergency construction of the causeway extension to DH 3 included a provision that modifications to the structure could be required if the biological need for such an action was determined. The State of Alaska and Federal regulatory documents have repeatedly opposed continuous fill causeways in the Beaufort Sea coastal zone or elsewhere (e.g., Alaska Coastal Management Plan, 6 AAC 80; Joint State/Federal Beaufort Sea Lease Sale Conditions). To alleviate these concerns, breaching of the West Dock could be con- sidered necessary for either or both of the following reasons: To ameliorate water quality and circulation changes caused by the existing or an extended causeway. To provide passage for migrating fish. Modeling studies and analyses reported in Sect ion 4.2 and Appendix D indicate that even several culvert breaches of the nature shown in Figure 2.5-21 would have negligible overall effect on the circulation patterns generated by 11 normal 11 wind patterns with the existing causeway plus an extension. These analyses show that the volume of water passing through a 6-m (20-ft) wide pipe (at the 1.8-rn, 6-ft, depth) under average (10 knot) wind conditions would be relatively slight compared to the volume moving shoreward through the pass between the causeway and Stump Island. Even the proposed 15-m (50-ft) bridge breach (Figure 2.5-5) would probably have only a limited effect on water quality beyond a few hundred meters from the causeway. Because of the high cost of constructing and rna intaining each breach, a breaching scheme, adequate to significantly influence the changes in water quality caused by the extended causeway, is not economically feasible. It is generally accepted (e.g., Craig and McCart 1976, Craig and Haldorson 1979, Bendock 1977) that large numbers of anadromous fish move east and west along the Beaufort coastline. It is evident that such fish moving between Prudhoe Bay and the east end of Simpson Lagoon will encounter and must bypass the existing causeway or abort their efforts. The proposed causeway extension would increase the chances that fish moving along the inner barrier island chain will also encounter the causeway and be forced to alter their path to bypass the structure. The proposed bridge breach in the extended causeway may allow a percentage of these fish to pass through the causeway, thus reducing their travel distance and perhaps reducing their exposure to predators that could congregate around the end of the causeway. The breach also would provide some fish, particularly those traveling eastward, an alternative to being led directly into the immediate vicinity of the intake screens. 2-71 I N I -....! N "'0 aJ c k I» -CD .., ~ 0 0 c. m :::J < -· .., 0 :::J 3 CD :::J -I» 3 'C I» (') -en -I» -CD 3 CD :::J - -n co c: .., CD 1\) 01 I 1\) ...... ELECTRIC HEATING PANEL(a) BOTH SIDES OF CULVERT (TYP.) CMP CULVERT WITH 7.6cm (3'') POLYETHYLENE INSULATION ·; .: . : .. ~ ~· .. ·. ·, ~--:. :' ~:-~·::; :: :;~< .. ; -: .:. ~. ·.~ ·. (a)ELECTRICAL EQUIPMENT TO BE INSTALLED, IF REQUIRED. SEMI-ELLIPTICAL BREACH FLARE END WITH BAGGED GRAVEL SLOPE PROTECTION (NOT TO SCALE) ,J ····A·'- Water currents through a breach would be expected to flow in the general direction of longshore currents. Thus, under a NNE wind, westward flow through the breach would bring lower salinity Sagavanirktok River water to the west side of the causeway. This plume could intercept fish keying on the chemical 11 scent 11 of· their home stream for guidance. On the other hand, a wind from the west would reverse the situation. A berm or fence angled outward and shoreward from the seaward side of a breach would increase use of the breach but would be difficult to maintain in an area of drifting ice. There is 1 ittle direct evidence upon which to predict fish attract ion to, and use of, either a culvert or bridge breach. Few, if any, arctic rivers containing anadromous fish have culverts approaching the size and length (90 m, 300 ft) of that described in Figure 2.5-21. Moreover, fish move up and down rivers in response to strong riverine currents; thus, the stimuli governing their movement patterns may vary greatly from those affecting movements offshore. Some Pacific Ocean salmonids (e.g., coho and chinook salmon, steelhead trout) readily pass through, over, and around a variety of breakwaters, causeways, culverts, ditches, and ladders to reach their spawning areas. However, other species (chum salmon) are very reluctant to do so (Stockley 1975). Chinook salmon adults may also refuse to enter culverts if no light is visible at the other end of the structure (Fiscus 1979). The proposed clear-span breach would maximize the 1 ikel ihood that fish would pass through the causeway as intended. The likely beneficial effects of a given breaching plan must be balanced against the impacts of the proposed causeway and intake on fish popu- lations, and the economic and engineering feasibility of a breach. Noticeable recent declines in anadromous fish populations in the Colville River commercial and Kaktovik subsistence fisheries have been reported by local fishermen (e.g., Craig and Haldorson 1979). Increased fishing pressure may contribute to these reported declines. However, there is little quantitative data to document these conditio~s. Reasonable worst-case estimates of losses to various harvested popul a- t ions with various breach types are provided in Sect ion 4.2, Marine _Biology. Under the worst-case scenario, it was assumed _that 20 percent of an-adromous fish passing the causeway would use a culvert breach and thus avoid the potential dangers of passing around the extension. A far greater percentage, perhaps 50 percent might be expected to use the more open bridge breach that is proposed. This figure has been used in assessing the potential impacts of the proposed project. In order to provide a breaching scheme with maximum utility for fish passage, the following criteria have been suggested by an ad-hoc inter-agency committee (Houghton 1980): Breaches should have maximum wetted cross-sectional area. 2-73 Breaches should intersect both the water surface and the seafloor to provide 1 ight to guide fisj1, air flow to speed melting, and a "natural" bottom. Based on the above, bridge breaches are considerably more desirable than closed culvert breaches. Breaches should be located inside DH 2 in about 1 m of water for fish moving along the shoreline) and in the extended causeway (to allow fish to bypass the intake). Breaches should be ice-free soon after breakup. At least 75 percent of the time, water velocity in a given direction should be within the-swimming speed capabilities of the weakest swimming anadromous species likely to be present. Allowable velocity would depend on the length of the breach. The Alaska Department of Fish and Game has proposed velocities of 15 cm/s (0.5 ft/s) for a 183-m (600-ft) breach, and 60 cm/s (2 ft/s, adults) for an 18-m (60-ft) breach to allow passage for various age classes of whitefish (Trasky 1980). These recommended velocities are probably conservative in that few whitefish younger than 2 years old have been taken along the causeway. Since winds average about 60 percent occurrence from the dominant direction (Figure 3.12-3) and since the unverified modeling analysis showed that velocity through a 6-m (20-ft) breach ,:would not exceed 21 cm/s (0.7 ft/s) (Appendix D), it appears that velocities through the type of breach shown in Figure 2.5-5 would not alone 'prevent the passage of most fish, most of the time. The State of Alaska (see Comments on DEIS, Vol. 3) has recommended that the breach allow passage of fish 90 -95 percent of the time. The proposed open-span bridge would maximize the suitability of a breach for fish passage. A rather unique combination of conditions complicates, the engineering design of a functional breach in the existing or extended causeway. Among these are: Width·. and height of the various segments of the causeway. Need to place waterflood piping within the gravel covering the breach. Presence of a permanent ice core in the causeway (considered important in providing strength needed to resist ice forces). Load factors (2000 tons) required for passage of heavy modules along the causeway (relevant to breaching the existing causeway). 2-74. Annual format ion of up to 2 m (6 ft) of ice with associated stresses. Alternative Breach Designs A semi-elliptical culvert breach is shown conceptually in Figure 2.5-21. The primary disadvantages of this type of breach would be the relatively smaller and less 11 natural 11 opening (e.g., 7.6 m, 25 ft), and lesser reliability (e.g. slower natural thawing rate). The proposed 15-m (50-ft) clear-span bridge would pass at least twice as much water as a 7 .6-m (25-ft) culvert breach and is expected to at least double the 1 ikel ihood of fish usage. The major advantage of a culvert breach in the extended causeway would be the lower cost of construction (rough- ly half that of the proposed breach). The practicality of applying this concept in the existing causeway is better than for a bridge breach because of the greater structural strength and the need to accommodate massive loads in excess of 2,000 tons. Any failure of a breach in the existing causeway could delay planned field development. A circular corrugated or smooth metal culvert with a diameter ( 1.8 - 3.0 m, 6 -10 ft) appropriate to the water depth and causeway height would be less expensive and easier to install than the semi-elliptical or open-span design. Disadvantages waul d inc 1 ude lesser 1 a ad-bearing strength, the relatively small wetted cross-section achievable, and the potential for damage every winter from expansion of freezing ice. Heating or evacuating the culvert to prevent freezing and to facilitate thawing at breakup is considered impractical over the life of the project. In addition, heating waul d increase the cost and perhaps reduce the strength of the causeway by. melting the permafrost core. Such a culvert would not intersect both the water surface and the seafloor if placed in water depth approaching its diameter. This design is thus considered less desirable than the proposed clear-span or alternative semi-elliptical breaches. Alternative Breach Locations Three alternative breach locations were considered in this analysis: in the extension near DH 3, in the extension near the seawater treating plant, and in the existing causeway between DH 2 and shore. Three of the numerous potential combinations of the two desirable breach designs at one or more of these three locations have been analyzed (Figure 2.5-22). All of these alternatives include a breach in the extension outside DH 3. Breach Alternative A (Figure 2.5-22) consists of a 7.6-m (25ft) semi- elliptical breach at the same location as the proposed breach. This alternative waul d probably reduce the number of fish using the breach and would be the least efficient of these four breach alternatives in minimizing the adverse effects of the proposed causeway extension. Under the reasonable worst-case scenario developed in Section 4.2, 2-75 SEAWATER TAEA TING PLANT---.:.--; EXTENDED CAUSEWAY 25'. DIAMETER _/ CULVERT BREACH EXPANDED CAUSEWAY A ·- SEAWATER TREATING PLANT~. 25~ DIAMETER CULVERT BREACH EXTENDED CAUSEWAY 25' DIAMETER _/ CULVERT BREACH .EXPANDED CAUSEWAY -OOCKHEAO NO. 2 B .-DOCKHEAD NO. 2 -------· SEAWATER TREATING PLANT EXTENDED CAUSEWAY EXPANDED CAUSEWAY c (Proposed) -DOCKHEAD NO. 2 SEAWATER TREATING PLANT EXTENDED CAUSEWAY EXPANDED CAUSEWAY D 16.4• DIAMETER c'ULVERT BREACH----I""#'// I -~- 1 DOCKHEAD NO. 2 ALTERNATIVE PLANS FOR CAUSEWAY BREACHING ! PBU Waterflood F" 2 5 _22 lj:nvironmentallmpact Statement lgure · I , . Marine Biology, this alternative was projected to increase project- caused declines in Sagavanirktok and Colville River fish from 3.5 and 2.6 percent to 5.5 and 4.0 percent, respectively. These figures are speculative, however. Alternative B (Figure 2.5-22) incorporates, in addition to the appli- cant•s proposed breach, a semi-elliptical breach near the seawater treating plant. This location is considered because fish moving eastward along Stump Island might encounter the extension seaward of the proposed breach and thus not be afforded the opportunity to pass through and avoid the intake area. This would become especially important if Stump Island elongates toward the proposed extended causeway. The effectiveness of the screening system employed will influence, in large measure, the need for such a breach. The proposed bypass system is expected to be efficient at reducing fish losses and thus waul d reduce the need for this breach. Alternative C is the applicant•s proposed breaching configuration. Under Alternative D (Figure 2.5-22), a single 5-m (16.4-ft) or two 3-m (10-ft) semi-elliptical culvert breaches inside DH 2 would be added to the clear-span bridge of Alternative C. In addition to maximizing fish passage through the extended causeway, this scheme would partially restore the historic nearshore migration routes disrupted by construction of the existing causeway. It has the added advantage of being in the most shoreward location and conceptually being available to the greatest numbers of anadromous fish. Overall mortality due to the causeway and intake would be reduced again by the percentage of fish using this breach. In addition to the alternatives shown on Figure 2.5-22, a breach could be built at this location under either the gravel island or dredged channel intake configuration alternatives. However, construction and maintenance of a breach in the existing causeway would be expensive and difficult. Maximum size of such a breach would be 1 imited by the height of the causeway in this area and the grade re- strictions of module-carrying crawlers. Alternative Intake Screen Designs and Impacts Alternates to the proposed intake design include the use of conventional vertical travelling screens, centerflow screens, finer screen openings, and a jet pump in the return line (see Appendix H). Both the centerflow screen system and the vertical traveling screen system with fish buckets (Figure 2.5-8A) would substantially increase the handling of fish over the proposed fish bypass (guidance) system. Both alternative systems rely on impinging and removing fish by screen rotation and wash. Lower survivals may be expected from these systems. It is assumed that any of the alternatives would place fish in the marine life return system. A water velocity of 1.2 m/s (4 ft/s} or more would return fish to the sea. 2-77 Finer screen openings would protect small organisms, including some invertebrates and larval and juvenile fish, thus decreasing entrainment losses. However, due to icing problems, fine-opening screening may not be feasible for this intake. Use of a jet pump to provide flow in the marine life return line would reduce the potential for physical stress to fish and probably increase survival. Based on observed intake operations and laboratory experi- ments, it appears that the proposed high-velocity, angled screen and bypass intake, if fitted with a jet pump return system, could provide over 90 percent survival of fish entering the system as compared to 70 to 80 percent survival for alternative systems or the 86 percent expected with the proposed guidance and return system (using an impeller pump) (see Appendix H). Seawater Treating Plant Various alternatives were considered to several aspects of the design of the seawater treating plant: type of prefiltration solids removal treatment, type of filters, type of deaeration, mode of operation of the outfall line, and p)ant locations. Clarification and ,(iltration Clarifiers, initially proposed to improve filter performance, demon- strated a low efficiency. Therefore, backwashable strainers were proposed for the removal of suspended fibrous material. Cartridge and precoat filters were considered in lieu of media filters. However, cartridge filters with sufficiently fine mesh elements to effectively remove the small suspended particles in the seawater would require an unacceptably high frequency of replacement and would result in high operating costs and filter element disposal problems. Precoat filters using diatomaceous earth would provide the necessary filtration efficiency, but would be difficult and costly to operate. Because the diatomaceous earth coating must be removed during each backwash cycle, the total solids in the outfall would be increased significantly. Also considered was an extension of the intake to deeper water north of DH 3 to provide essentially sediment-free water year-round, thus reducing the need for filtration. However, it was found that summer storms agitate the bottom sediment throughout the entire area inside the outer barrier islands. Therefore, this alternative would not be effective in eliminating the need for filters. Several alternatives were examined to reduce or eliminate discharges of filter and strainer backwash sol ids and chemical residues directly to the Beaufort Sea. These alternatives included open pits or settling ponds, centrifugation, incineration, landfills, and discharge on top of the ice during winter. As discussed below and summarized in Table 2.5-7), all were deemed to be impactical for economic, technical, or environmental reasons. 2-78 N I Outfall Line (Ocean Discharge) Set t 1 i ng Ponds ""-1 • \.0 Settl1ng Tanks Centrifugation TABLE 2.5-7 COMPARISON OF ALTERNATIVES FOR WASTE TREATMENT DISPOSAL Reliability Susceptible to biofouling. Susceptible to freezing if shut down with no freeze protection. Extremely high cost to enclose and heat for assured reliability. Freeze protection for onshore pipeline difficult. St i 11 requires P.l!tf a 11 pipeline. Extremely high cost to enclose and heat for assured reliability. Still requires outfall pipeline. Cleaning of tanks compli- cates design. Particle size and distri- bution may not allow effective centrifugation. Additional equipment required: centrifuges, pumps. Less reliable due to possible breakdown of additional equipment. Still requires outfall pipeline. Efficiency Engineering Feasibility Most efficient overall. Feasible. Proper design and location should prevent recycle back to intake. Large amounts of building heat Not a practical alternative. required. Additional pumping required. Additional heating required for pipeline freeze protection. Cleaning of ponds. requi.res. · additional equipment and labor, and use of multiple ponds. Landfill required for wet solid disposal. Additional heating required Not a practical alternative. for pipeline and tank freeze protection. Additional pumping required. Cleaning of tanks requires additional equipment and labor. Landfill required for wet solid disposal. Questionable if process is effective for design conditions. Process produces clean and dirty effluent. Clean effluent is better than proposed discharge but would still need to go back to ocean. Dirty effluent requires land- fill. Questionable feasibility. May not be effect i've process. Environmental Effects Potential impacts on some marine organisms within limited mixing zone. Impacts large amount of land surface area for ponds. Requires separate landfill area for disposal of material. Onshore pipeline required. Potential saltwater spill in freshwater wet 1 ands. Leaching of salt deposits in 1 andfill. Heating of buildings/ponds may affect permafrost. Impacts large amount of land surface area for tanks. Requires separate landfill area for disposal of material. Onshore pipeline required. Potential saltwater spill in freshwater wetlands. Leaching of salt deposits in landfill. Requires separate landfill area for disposal of material. Requires outfall pipeline for disposal of water. Leaching of salt deposits in landfill. ."''''1'1!\1. ·' --~:,· '>:) t~ N I co 0 I Incineration Landfi 11 (Wet Disposal) TABLE 2.5-7 (continued) COMPARISON OF ALTERNATIVES FOR WASTE TREATMENT DISPOSAL Reliability Additional equipment required: concentrator, pumps, incinerator. Less reliable due to possible breakdown of additional equipment. Still requires outfall pipeline. Onshore pipeline more of a freeze protection problem. Winter disposal difficult. Efficiency Requires greatest additional energy input --handling, pumping. Also requires concentrator up- stream, outfall line and landfill. Very low efficiency --only 17 -27 percent of waste material might be consumed. Requires pumping. Requires ability to vary dis- charge point to avoid over- fill. Transportation of wet solid material presents freezing problems in winter. Highly inefficient in winter. Heating required for trans- portation. ... Engineering Feasibility Impractical since it still leaves 75 -80 percent of _materi~ for disposal on landfill and has a poor quality water ~ischarge. Not a practical alternative under arctic conditions. Environmental Effects Additional air emissions. Requires separate landfill area for disposal of unburned material. Leaching of salt deposits in landfill. Impacts largest amount of land surface area. Onshore pipeline required. Potential saltwater spill in freshwater wetlands. Leaching of salt deposits in landfill. Possible damage to the permafrost. j --- Open pits or settling ponds would require storage for 800,000 m3 (1.1 mill ion yd3) of frozen backwash during the the winter period (26. 7 ha if 3 m deep, 66 acres if 10 ft deep). An additional pipeline would be required to transport this material and leaching ()r spillage of saltwater from the system would be a hazard to wetlands. Ponds could be used during the open-water period, but the added cost of having two disposal schemes does not appear to be warranted, particularly if the applicant can meet the Alaska water quality standards at the edge of the ADEC approved mixing zone. Also, ponds could not be used with the gravel island alternative. Landfi 11 ing unconcentrated filter and strainer backwash waul d be technically possible. However, the large volume of solids and saltwater make this alternative impractical from economic and environmental viewpoints. On an annual basis, 1.8 million m3 {467 million gal) would have to be trucked and landfilled. The backwashed solids could be piped to a landfill site, but the pipe would have to be moved frequently because one site could not handle the volume over the 20-year 1 ife of the project. Over 20 years, 35 million m3 (46 million yd3) of landfill space would be required (this volume does not consider expan- sion due to freezing or loss due to evaporation --it is doubtful that the soil would be able to accommodate much of the volume because of permafrost and relatively high soil moisture content). Leaching of high salinity water to the surrounding tundra is also a possibility. Centrifugation could be used to concentrate solids prior to landfilling. However, this method was considered less reliable than that proposed. Moreover, install at ion costs waul d be substantially greater since the treating plant waul d have to be expanded to accommodate additional equipment. Operation costs would also be higher because the solids would require trucking to a landfill site and because of potential freezing problems in winter. Transporting solids would impose substan- tial logistical problems for the gravel island alternative. As with the above landfilling and settling pond alternatives, saltwater from the centrifuged slurry would require careful handling and disposal to avoid impacts on terrestrial and wetlands habitats. Incineration of the slurry would not be a reasonable alternative because most of the solid material would be incombustible. Incineration would cost an estimated $300,000/yr (exclusive of transportation costs) and might require expansion of existing North Slope Borough facilities. Samples of suspended solids from the project area displayed a mean loss on ignition of 17 percent during open water and 27 percent under ice; therefore, approximately 73-83 percent of the solids is incombustible. Disposal of wastes from the water treatment process in an on-1 and area has the obvious advantage of avoiding the adverse environmental effects of a marine discharge. However, because of the technical difficulties imposed by arctic conditions, higher costs, and environmental effects of • 2-81 these various on-land alternatives, discharge to the sea is considered the most prudent and practical approach. Discharging backwash sol ids on top of the ice during winter was dis- missed because of the likelihood of creating a large ice island that might not melt the following summer. There would be 3180 m3/d (840,000 gal/d) of backwash material discharged over a conservative 260-day winter, or 800,000 m3 (218 million gal) discounting expansion due to freezing. Discharge at one location could create an ice island that might persist through the summer. Multiple discharge points would increase manpower and energy costs. If heavy equipment were required to move pipes to multiple discharge points, this equipment could not be used in some years until mid to 1 ate February when the ice waul d be thick enough to support the effort. The ice island thus formed would be likely to be at least as damaging to benthic populations as would accumulations of solids expected from the proposed under-ice discharge. Biocides Three biocides were considered for use in the seawater treating plant to prevent biological clogging of filters: chlorine (proposed), hydrogen peroxide, and ozone. Both hydrogen peroxide and ozone rapidly dissipate to harmless products in the environment. However, this same breakdown would release dissolved oxygen to the water and tend to defeat the function of the de aerators, one of the system components requiring biocide treatment. Costs of coping with this situation while maintain- ing very low dissolved oxygen in the low-pressure pipelines led the applicant to favor chlorine. Because chlorine generators are readily available, sodium hypochlorite can be generated onsite; thus, obviating chemical shipments to the site (Metz l980b). · Coagulant Three potential coagulants have been identified for use in the treatment proce~s. The recommended coagulant, Visco Koagulan 3332, is a solution of polyquaternary amine chloride. The others are solutions of poly- aminoesters or polyamines. These coagulants are cationic polyelectro- lytes that provide positive 1=harges required to neutralize negative colloidal particles, allowing the particles to form a floc. A coagulant is necessary to provide water for injection having 3 mg/1 or less of suspended solids (Metz l980b). The applicant will design the method of adding coagulant to the flow stream to insure proper mixing and optimum dosage so as to use a minimum amount of coagulant. Coagulant cost and shipping charges motivate the applicant to use as small a dose as possible to obtain acceptable water quality. It is also recommended that the applicant continuously monitor total suspended solids at the intake to optimize the coagulant dosage. 2-82. Deaerat ion Alternatives to the proposed vacuum-gas deaeration method were chemical scavenging and stripping with natural gas. Vacuum alone was eliminated because of process inefficiency. Chemical scavenging was eliminated by the applicant because of the high cost for the large volume of scavenger· chemicals required. Stripping with natural gas was rejected because the high carbon dioxide content of the available natural gas would cause the deaerated seawater to be corrosive. There would be no significant difference in the environmental impacts of any of these alternatives. Outfall Line Operation The outfall line could be operated at a constant flow rate by flushing it with raw makeup seawater whenever filters were not being backwashed. Although this would reduce the average concentration of suspended solids 'in the effluent, the total quantity of solids discharged would increase due to the much larger quantity of water discharged. The annual 47 galls average outfall flow rate with no makeup would be 0.18 m3/s (2850 gal/min); if the flow rate were held constant, it would average 1.10 m3/s (17,430 gal/min). Treating Plant Location Locating the seawater treating plant onshore as a conventional modular plant, similar to existing production facilities in the PBU, would require more space, materials, labor, construction support, and heating fuel, and would be more expensive than a plant located offshore. An onshore plant would still require offshore intake and pumping facilities. It would also require location on ecologically sensitive coastal tundra near the base of the existing causeway since existing pads are fully uti'lized and less sensitive upland sites are too distant from the shoreline. Outfall Pipelines Marine Life Return Line The marine 1 ife return 1 ine for each alternative intake configuration would be located to return bypassed animals to the sea as quickly as possible. The chance of reintroduction of sea life through the intake would be minimized by placing the outfall either down current (for the island (B) alternative) or on the opposite side of the causeway (for the proposed (A) and DH 3 (C) alternatives). If breaches in proximity to the treati,ng plant were included as mitigation in these latter two alternatives, the location of the marine life return line should be adjusted accordingly. 2-83 Main Outfall Line Both offshore (proposed) and inshore configurations were considered for location of the main outfall line. Each location was judged with respect to dispersal qualities, risk of recycling discharged water, length of pipeline trench required, length of pipe required, and risk of ice damage. Unverified circulation modeling (Appendix D) indicates that under west wind conditions, some recycling is possible with the inshore configuration. According to Mangarella (1980), the probability of a minor amount of recirculation of TSS within the discharge plume is high for the inshore location in the under-ice case. Locating the outfall line offshore of the treating plant would virtually eliminate chances of recycling and would be necessary for the discharge to comply with State water quality standards. An inshore location would require about the same amount of trenching and less pipe but would decrease vulnerability to ice damage of the pipe and diffuser section. The inshore location would provide less volume of water and generally weaker currents for dilution and dispersion. of effluents and thus would require a 1 arger surface area mixing zone. Effects on biota would not differ appreciably from those of the proposed alternative. The possibility that eastward growth of Stump Island would constrict, or close off completely, the pass between the island and the causeway may be the strongest factor favoring the offshore location. In addition, the ADEC approved mixing zone was designed so that water quality standards would be met at the 4.3-m (14-ft) depth. Dredging Alternatives Dredging Methods There are two reasonable alternatives to the clamshell dredging method: hydraulic suction dredging and cutter suction dredging. Both of these methods can move a greater volume of sediments than clam shell dredging and both create less turbidity at the dredge site. Both suction dredges can be used to deeper depths than the clam she 11 dredge. Thus, for offshore gravel removal operations, a lesser seafloor area need be disrupted for extraction of a given volume of gravel. However, equip- ment and operation costs are greater for these methods, considering the relatively small quantity of material to be dredged (some 18,700 m3, 24,300 yd3) for the proposed project. Additional dredging requirements (e.g., for offshore gravel sources, dredged channels, etc.) would increase the economic feasibility of using hydraulic or cutter suction dredges. Di sposa 1 Areas Active backfilling of pipeline trenches would promote a more rapid return to a near normal benthic community than the proposed along-side 2-84 disposal of dredged materials. It would also represent the least effect on currents. Double handling of dredged material, however, would increase turbidity and elevate dredging costs. Under the gravel island alternative, backfilling of the pipeline trench to DH 3 would be highly desirable to protect the piping from possible ice gouging in the first winter after placement. Onshore disposal of dredged material would reduce the short-term increase in turbidity caused by open-water disposal. It would, however, have various long-term adverse effects. An on-land site within a practical distance from the dredging site would likely directly destroy wetlands or indirectly increase the chance that other field development would destroy wetlands because of site competition. Saltwater leaching and subsequent long-term degradation of surrounding habitat could also occur. An upland disposal site beyond the Prudhoe Bay development area is considered impractical. Low-Pressure Pipeline Routing The major onshore aspect of the Waterflood Project for which feasible alternatives exist is the routing of low-pressure piping to the west side of the field. The proposed alternative (A-1) calls for a new section of road and pipeline rack between Well Pad K (Term Well A) and Well Pad E, a distance of some 3.4 km (2 mi) (Figure 2.5-23). Total distance from the module staging area at the causeway base to the west injection plant would be about 11.5 km (7.2 mi). Two alternative routes (A-2 and A-3) between Well Pad K and Well Pad E were considered to minimize the impacts of this road section on the drained-lake basin complex system in this area. Route A-3 follows the 11 ridge 11 of an ancient drained lake and avoids valuable wetland habitat to a great extent. This route is the least environmenta1ly damaging of the Pad E to Pad K alignments. Other route variations were also considered, including an 11 S11 shaped alignment and other loop configurations. An alternative route (B) is available that would follow existing roads and/or pipelines for a total distance of 18.5 km (11.5 mi) and completely avoid the relatively natural area between Well Pad K and Well Pad E. This area has been used historically by caribou and is important for sever a 1 species of shorebirds and waterfowl although the State of Alaska (comments to DEIS, Vol. 3) has indicated that caribou use in this area is limited. Alternative B would follow the existing road from the module staging area to the CCP. From there it would follow an existing work pad to a junction with the east-west spine road near GC 3, and the spine road to the west injection plant. Table 2.5-8 and Figure 2.5-23 provide a comparison of these routes. Alternative B would require little, if any, new gravel placement for waterflood use, but would requ]re an additional 6.9 km (4.3 mi) of 91-cm (36-in) pipe. It is estimated that the initial cost would exceed that 2-85 FEET 3000 APPROXINAn: SCALES PBU Waterflood Environmental Impact Statement Figure 2.5-23 2-86 w Q en l-en w ;: 0 l- en w I-=> 0 a: w z .J w 9: CL w a: ::> en en w a: Cl. I ;: 0 .J w > 1- <C z a: w 1- .J <C N I 00 ....... Alternative A (Proposed, via Well Pad E) Alternative A-2 Alternative A-3 Alternative B (via CCP and Gathering Center 3) TABLE 2 .5-8 COMPARISON OF LOW-PRESSURE PIPELINE ROUTE ALTERNATIVES Direct Natural Distance Gravel Habitat Destruction km (mi) Required m3 (yd3) ha (acres) 11.5 (7.2) 99,000 ( 130,000) 6.1 (15 .1) 14.1 (8.8) 153,000 (200,000) 10.8 (26.6) 12.7 (7.9) 112,000 (147,000) 7.2 (17.9) 18.5 (11.5) Constr{cyion Cost a $55,000,000 $67,500,000 $60,000,000 $80,000,000 +$21 ,000,000 Incremental Transport at i~n Cost per year b) Base + + +$215,000 (a) Includes capital cost of pipeline, supports, ice road for construction; also contingency and escalation. (b) Does not include savings in vehicle and module traffic to west side of the field or Kuparuk. of the proposed alternative by about $25 million and an additional $215,000/yr in pumping costs would be required to move water through the longer pipeline. In addition, this alternative would not provide the more direct route for modules and other traffic to the west side of the field, including the Kuparuk area. A final disadvantage relates to the fact that Term Well A will be developed as a production Pad (Well Pad K) in the near future. Once Pad K is developed (independent of waterflood) the applicant has indicated a road to Well Pad E will be necessary for production operations. Sohio has applied (NPACO No. 071-0YD-4-790446 of 11 January 1980) to construct this road independent of the Waterflood Project. This new road also would serve as a multipurpose road for oil movement, modular traffic to the west side and Kaparuk, as well as the low-pressure line for waterflood. As a general policy, multiple use of existing facilities is favored to reduce environmental degradation. The work pad between the CCP and GC 3 is currently gated and receives relatively little traffic. The portion between GC 3 and waterflood injection pad (WF 1) would be upgraded and opened as a full-time road as part of the proposed action. However, the remainder (WF 1 to CCP) wou1d remain gated under the proposed alternative. This portion would also be upgraded and receive substantial traffic under Alternative s·, thus increasing disturbance of habitats along this route. Low-Pressure and High-Pressure Pipeline Construction Alternative modes of pipeline constr~ction are as follows: Pipe 1 i nes on pile-bent supports (proposed alternative; Figure 2.5-11). Pipelines above grade on wooden sleepers placed on a gravel berm. Pipelines abOve grade buried in a gravel berm or access road. Pipelines buried in the tundra. Above-grade construction on wooden sleepers on a gravel berm would require more gravel and destroy more terrestrial and wet 1 ands habitat than the proposed method. It would also complicate maintenance by accumulating snow drifts and would be technically difficult to anchor and guide to accommodate thermal movements and forces. Pipeline constructed above grade and buried in a gravel berm or road would require more gravel, destroy more habitat, and have a higher initial capital cost than the preferred alternative. Restricted access to the pipelines for inspection and maintenance would be a problem. However, above grade buried pipe in a gravel berm or road would reduce problems of caribou passage, providing fill did not exceed 1.2 m (4 ft) above existing grade (Hanson, in press). 2-88. Burying pipelines in the tundra would require excavation with resultant damage from spoil banks and equipment movements. Revegetation and restoration of damaged tundra would be difficult and time-consuming and might lead to erosion and thermal degradation of permafrost. Access for inspection and maintenance would be restricted and a higher capital cost would be associated with construction. The proposed alternative is a geotechnically field-proven technique and would require the least gravel since existing pads, roads, and other pipelines follow most of the proposed route. Thus, loss of habitat and interference. with existing drainage patterns would be minimized. Existing pile-bent supports would be used along much of the routing. Where new lines are run, provision would be made for caribou passage by burying pipe in a gravel berm (<1.2 m, 3.9 ft) or by elevating pipe at caribou crossings to a minimum clearance of 1.5 m (5 ft). Inject ion Plants Four major alternative inject ion plant configurations were evaluated: Two injection plants; one adjacent to Gathering Center 1 and the other adjacent to Flow Station 1. This is the applicant•s proposed alternative. Six injection plants; one adjacent to each of the existing production centers. One land-based injection plant located near the center of the oil-producing area in the general vicinity of Alyeska Pump Stat ion 1. One offshore injection plant mounted on the platform with the seawater treating p 1 ant. Compared to the proposed configuration, each of the other alternatives had features which in sum made them less desirable. The six-plant alternative would have a higher capital cost and would require a larger total area, larger operating force, increased operating costs, and more gravel than the proposed alternative. This alternative waul d require relocating or adding high-pressure inject ion pumps and other equipment at one or more of the plants if reservoir response should require redistribution of water injection across the field. The single 1 and-based plant alternative waul d involve approximately the same capital costs as the proposed alternative. Approximately equal area and gravel requirements would be incurred, but the facility would be located in a new operations area. A slightly smaller operating force would be needed. If reservoir response should require redistri- bution of water across the field, additional lengthy, high-pressure transfer pipelines would be needed. 2-89 Capital costs for a single offshore injection plant would be approxi- mately the same as the proposed alternative. There would be less onshore, but increased offshore, area and gravel requirements. A slightly smaller operating force would be needed. This alternative would require additional lengthy (21 km, 13 mi, to the east operating area; 16 km, 10 mi, to the west), high-pressure transfer pipelines if reservoir response should require redistribution of water across the field. The proposed alternative offers the most flexibility for responding to reservoir requiirements over the 1 ife of the waterflood. The initial capital costs <;ire no higher than other alternatives. The surface area, gravel area, a~d access needs are also no greater than for the others. Environmental gimpacts are relatively slight for all alternatives. ·'' 1: Fuel and Power \Systems An elevated power line along the causeway to the seawater treating plant would be likely to kill birds colliding with the wires in the course of normal east-west migrations along the coastline. Although the magnitude of this impact cannot be quantified, it would be exacerbated by the frequent periods of foggy weather. However, unusual weather conditions could cause isolated instances of higher mortality and affect local bird populations on a short-term basis. Pipeline Freeze Protection Five major alternatives were evaluated: Proposed system, as described in Appendix B. Heat tracing. Complete displacement with methanol/water. Dual pipeline systems with heated water circulation. Complete displacement with crude oil. A heat tracing system would be less reliable than the proposed system (if electric power system is down), and would have higher installation costs (additional electric power generation required) and higher operating costs. Complete displacement with methanol/water would also require higher installation and operating costs. It would require large volumes of methanol, methanol storage, and methanol handling equipment. Dual pipeline systems with heated water circulation would have a much higher installation cost than the proposed system. Complete displacement with crude oil could be instituted; however, it would be difficult to remove cold crude oil from pipelines and residual crude oil would damage injection wells. 2-9o· While two of these alternatives (heat tracing and dual systems) would eliminate the potential need for emergency discharge of low-pressure pipeline contents to the sea, the flexibility of the proposed system appears adequate to reduce the likelihood of this occurrence. Freeze Protection of Injection Wells and Well Lines Four major alternatives were evaluated: Displacement with methanol/water. This is the proposed system as described in Appendix B. Displacement with natural gas. Displacement with diesel. Warm glycol/water circulation in the well tubing/casing annulus. Displacement of injection line water with natural gas could form hydrates that would plug the wells. Higher capital costs would be required to provide the needed high-pressure gas supply 1 ines. Diesel oil would form an emulsion with water and subsequent injection would damage the injection well. Warm glycol/water circulation in the well is feasible technically but would require excessively higher capital costs due to extensive refitting of all existing wells used for injection. Environmental impacts are relatively slight for all alternatives. Road and Pad Construction Two alternative methods are available for road and pad construction across permafrost: A thick (1.2 -1.5 m, 4 - 5 ft) gravel pad (the proposed alternative). A rigid insulation on the ground surface covered with a thin (0.3 -0.6 m, 1 - 2 ft) gravel layer. The low-profile road, achievable using a rigid insulating layer, is generally preferable to the proposed alternative. It waul d require less gravel and create less of a visual barrier to large game (caribou) movements. The permafrost core that forms in high-profile pads and tends to block all surface water movement (Davidson in press) may also be mitigated with the low-profile road because of the more rapid thawing of the thinner gravel 1 ayer. Cost of the insulating material delivered and installed at Prudhoe Bay is high but exceeds the cost of the extra gravel required for a 1-m plus pad only if gravel haul distances are less than about 3.2 km (2 mi) (Kalaska 1979; assumes an 8. 5-m, 28-ft, road top width) . Thus, for the proposed road from We 11 Pad E to Term Well A, the low-profile road would appear to be more 2-91 economical assuming that load capacity was adequate for all intended uses and that existing gravel sources are used. The polystyrene insula- tion material is very stable and would require special attention during project abandonment. Gravel Sources Alternative gravel sources considered for use include (Figure 3.3-6): Existing sources such as the Put Oxbows, Sag C, and Kapuruk Dead Arm (the proposed alternative -includes deep mining of existing sources). ,; J,. New on-land gravel pits!f 1\ Off sh,ore deposits • J• I· ,. Opening new on-1 and gravel sources would disrupt more natural habitat than would expansion of existing pits, depending on depths that could be mined. Road access to the new areas would probably be needed although, depending upon location, the total haul distances to some portions of the Waterflood Project (such as the causeway expansion) could be significantly reduced (by a new pit at the base of the causeway). Specific impacts of new on-land sources cannot be addressed until potential sites are identified. State resource managers are seriously considering a new gravel pit located near Deadhorse (Smith 1980). There may be some logistical and environmental advantages (e.g., less permanent habitat disrupt ion) to using offshore areas for causeway extension or gravel island construction as an alternative to opening new upland sites.· AEIDC {1980) has summarized the potential impacts of extracting gravel from an area north of Stump Island in about 3 -8 m (9 -25 ft) of water (Figure 3.4-1). Major impacts would result from disposal of overburden, direct loss of benthos and down-current effects on benthos and plankton due to turbidity plumes. The full extent and quantity of the offshore gravel supply has not been sufficiently deter- mined, but it :may be a viable source for offshore construction. If offshore mining is permitted, consideration should be given to pro- hibiting extraction during the 1 ate September and October fall migration period for bowhead whales. Labor, Supplies, and Services As an alternat'ive to continuation of current oi 1 industry recruitment, hiring, and training practices for local residents, the applicant could institute a broader program similar to that recently enacted by the State Legis 1 ature for imp 1 ement at ion during gas pipeline construct ion. Such a plan would expand the employment opportunities for local resi- dents. A flexible employment program also could be instituted that would enable native employees to continue traditional hunting and 2-92· fishing activities. This would assure a continuum of knowledge impor- tant to life in the Arctic, and would allow a smoother transition back to a subsistence life-style upon project abandonment (Worl 1980). Project Abandonment The applicant has made public no project abandonment plans other than that the area and facilities would be left in a condition that would satisfy the Commissioner of the Alaska Department of Natural Resources. As -an alternative, the applicant could be required to take reasonable steps to enhance the rate of natural recovery or restore the area to near its former condition. Such measures could fnclude salvage of all metals, removal of modules and buildings, reuse or stockpiling of gravel, opening breaches in the causeway to accelerate erosion and restore fish migration pathways, and substrate preparation and revegeta- tion of work pads and road areas. The applicant could be required to submit abandonment plans for agency approval, for example 5 years prior to scheduled abandonment. 2.6 MITIGATIVE MEASURES Alternative approaches to Prudhoe Bay waterflooding, other than those considered in detai 1 by the applicant (Section 2 .5) are described in this section along with other measures that could be implemented to mitigate any project impacts. These and other measures were considered in arriving at the potental permit conditions discussed in Chapter 5.0. FISH GUIDANCE MEASURES If on-site operational monitoring programs (Chapter 5.0) indicate that an unacceptably high rate of fish mortality is occurring at the water treating plant intake, there are some measures that could be undertaken (in conjunction with in-plant modifications) to reduce the impact. Such measures would include a "bubble curtain" or diversion net set up outside the treating plant to divert fish before they become entrapped. A bubble curtain immediately in front of the trash racks would aid in ice control and could cause behavioral avojdance of the intake by some fish (e.g., Bell 1973). A fine mesh diversion net with float and a lead line stretched from the causeway extension diagonally across the intake to the southwest corner of the treating plant protective berm could be readily installed during the 1 ate summer period if high fish abundances are found in the area. Such a protective net has been found to be a highly effective and inexpensive way to prevent fish from entering high-volume intakes or water diversions (Stober 1980), but would require removal prior to freeze-up. Bubble curtains or diversion nets external to the plant would require a continued maintenance effort to control marine fouling and to prevent damage due to drifting ice and debris. 2-93 LOW-PRESSURE PIPELINE EMERGENCY DISCHARGE Discharge to the Beaufort Sea of the deaerated and chemically treated water in the low-pressure pipeline is highly unlikely and would occur only if other freeze protection measures failed. However, potential impacts could be virtually eliminated by a relatively simple design modification to allow over-ice discharge. A diversion valve would be installed in the low-pressure pipeline or in the discharge 1 ine near the water treating facility. From this diversion valve a line could be installed over the treating plant berm. During breakup, the aufeis formed would gradually melt along with the unde~lying ice and any residue of the antifoaming agent and corrosion or scale inhibitors (should they be in use) would be harmlessly diS;tributed with the drifting ice. a :. ~ DRAINAGE READJUSTMENTS A potential mitigating measure to compensate for terrestrial impacts of new roads and pads required for waterflood piping would be to alleviate drainage pattern alter at ions created by earlier field developments. Several areas where pad construction has caused ponding are evident in aerial photos of the field. Some of these ponds have damaged underlying tundra beyond recovery. In others, the underlying tundra may recover if drainage is restored. Currently, the PBU owners are working with the USFWS to correct drainage problems where restoration of productivity -appears possible (Meehan 1980a). RESTORATION OF GRAVEL REMOVAL AREAS The applicant is committed to work with cognizant resource agencies to take reasonable steps to restore depleted gravel removal areas to beneficial uses. Such uses may include freshwater reservoirs (e.g., Kuparuk Dead Arm), overwintering habit at for fish, or revegetation to encourage return to productivity. More detailed discussion of possible restoration measures is provided in Section 4.2, Geology and Soils. SITING TO AVOID WETLANDS Detailed terrestrial and wetlands habitat mapping (Appendix L) provides a tool for siting project comppnents for maximum avoidance of more productive 11 h igh-val ue 11 habitats~ Location and direct ion of specific pad expansions have been reviewed with the applicant's engineers and, where feasible, reoriented to avoid such areas. An area-wide or regional approach to environmental evaluation could take place, thus reducing adverse cumulative impacts. Such an evaluation has been committed to by the Alaska Department of Natural Resources. 2-94 PROTECTION FROM ICE OVERRIDE Added protection from ice override may be available through design changes (i.e., adding an irregularity in the gravel slope; Hardy Associates 1980) or by instituting an early warning system that would sense ice movements and allow additional preparation time. PROCEDURAL MEASURES Avai 1 able evidence indicates that moist graminoid tundra areas such as those found at Prudhoe Bay are more susceptible to long-term damage from saltwater than from oil spills (Webber 1979, see Section 4.2). Although accidental spills from waterflood piping are unlikely, their impact would be great. Therefore, procedures for control and cleanup could be developed and instituted. A long-term resource evaluation and environmental planning program could be implemented to reduce adverse cumulative impacts. MARINE LIFE RETURN LINE An antifouling coating in the line or use of an anti-fouling material such as a copper-nickel alloy for the pipe construct ion would further reduce the chances of physical damage to organisms. 2.7 THE ENVIRONMENTALLY PREFERRED PLAN The Corps of Engineers has identified an environmentally preferred alternative according to regulations of the President•s Council on Environmental Quality. The major elements of the alternative are as follows: A gravel sea is 1 and constructed for location of the treating plant and seawater intake. The main marine outfall 1 ine would be located northward of the facility and the marine life return line would be to the west. Electrical power 1 ines buried in the causeway (not required for gravel island). A state-of-the-art flow-through fish bypass and return system in the intake structure. A 5-m (16.4-ft) culvert breach in the existing causeway. Alternative B (Figure 1) pipeline and road alignment. The above components were chosen among feasible alternatives primarily on the basis of ecological and social stability criteria. Implementing 2-95 this alternative would result in an actual improvement over present conditions for migrating anadromous fish, conceptually allowing an increase in populations over existing levels . This would avoid addi - tional stress on the traditional life-style at the Inupiat villages of Nuiqsut and Kaktovik and help assure adequate subs i stence resources . Also, no ecological change would occur to lower the value of Simpson Lagoon as a feeding habitat for fish, waterfowl and other animals (entrainment impacts would be similar to those of the proposed project). This plan avoids expected waterfowl and wading bird mortality due to powerline collisions and it would cause the least damage to valuable terrestrial habitat. This alternative represents a 11 least environmental; resource risk 11 approach to accomplishing waterflood . It would, however,, increase total project costs by about 10 percent, decrease reliability and efficiency, somewhat increase the difficulty of oil production i ct the Prudhoe Bay area, likely delay project start-up for 1 year, and perhaps increase the risk to worker safety . t ; .... - 2-96 CHAPTER 3.0 AFFECTED ENVIRONMENT 3.1 INTRODUCTION A significant body of information exists about Alaska's North Slope and Beaufort Sea. Most scientific studies are of relatively recent origin, however, conducted as part of the International Biological Program or in response to the prospect for development of· oil and gas in the vast National Petroleum Reserve, the Prudhoe Bay area, and in the Beaufort Sea (OCSEAP). Although this EIS is based to a large degree on this existing information, additional study was needed in the primary impact area on water quality, effects of the proposed causeway and its alternatives, sediment chemistry, wet 1 ands and wi 1 dl ife habitat, and archaeological resources. Other essential information was not collected because of the 1 imited prospects to resolve scientific uncertainty. The proposed action and most alt;ernatives would be carried out within the existing oil development area 1,at Prudhoe Bay. In general, the study area and the baseline descriptions that follow concentrate on coastal and nearshore areas between the Sagavanirktok and Kuparuk Rivers, termed the "Prudhoe Baj area" or the primary impact area. Where evidence indicated some aspect of the proposed action or the alternatives could impact the environment outside this area, baseline descriptions have been expanded to cover additiona 1 geographic areas. The area from the Colville River on the west to the Canning River on the east is referred to as the "Prudhoe Bay region," while the term "North Slope" is used in reference to all land area from Point Hope to the Canadian border north of the crest of the Brooks Range. In certain instances reference is made to a state, national or global perspective. The North Slope of Alaska is a vast wilderness with small-widely scattered settlements of the native Inupi at people. The Prudhoe Bay area is an enclave for oil and gas development in the high Arctic, visually dominated by oil drill rigs, processing facilities and gravel roads. The nearest native village is Nuiqsut, located on the Colville River about 113 km (35 mi) west of the Prudhoe Bay development. Another village, Kaktovik, is about 208 km (130 mi) east of Prudhoe Bay on the coast of the Beaufort Sea. The North Slope has been home for the Eskimo for more than 2500 years. Prudhoe Bay has rapidly developed since oil discovery there in 1968. There is a significant potential for future hydrocarbon exploration and development in the 133-km (120-mi) distance between the Canning and Colville Rivers and offshore in the Beaufort Sea. Drill pads, artificial islands, pipelines, roads, and possibly marine causeways would accompany this activity. Although the Arctic Coastal Plain: and the Prudhoe Bay primary impact area have a 13-cm (5-in) annual precipitation rate, comparable to very dry environments; they are characterized by wet 1 ands, beaded streams and sma 11 1 akes. This phenomenon occurs bee ause permafrost, extreme cold, long winters, and flat terrain effectively concentrate water on 3-1 the tundra in the ice-free season (about 3 months), which corresponds to the period of most active vegetation and soil development. Wildlife in this area are 1 argely migratory. This behaviori al adapt at ion to dramatic seasonal changes and survival opportunities is one of the most sensitive aspects of maintaining viable fish and wildlife populations on the North Slope and in the coastal waters of the Arctic Ocean. Wildlife species that depend on the Prudhoe Bay primary impact area travel great distances. The annual flight of black brant from their wintering areas in California and Oregon characterizes many species of waterfowl that depend on wetlands in the area. Wading birds, exemplified by the sanderling and pectoral sandpiper, fly even greater distances, arriving on the high Arctic Coastal Plain for nesting from Argentina and Chile. The Central Arctic caribou herd moves from winter ranges near the Brooks Range northward to the coastal area each spring. Likewise, anadromous fish species essential in the native subsistence resource base for the villages of Nuiqsut and Kaktovik are very dynamic in the primary impact area. Adult arctic char, least and arctic cisco, whitefish, and other species move annually from the Colville, Sagavanirktok, and Kuparuk Rivers to shallow coastal waters of the Beaufort Sea to feed, returning each fall to their natal freshwater streams to spawn and overwinter. Although studies are 1 acking in this area, the ability for anadromous fish to move significant distances along shore is believed essential in maintaining abundant populations. The species discussed above and the ecosystems they represent are linked to the Eskimo both culturally and by diet. Recent technological changes and the Eskimo's organization into functioning political and economic units of a Western nature have not significantly altered the traditional Inupiat view of their close relationship to the land and sea. Fish, waterfowl, caribou, and other species are important in their diet from both a biological and psychological perspective. 3.2 PREHISTORY/HISTORY To adequately examine the proposed action requires placing it in his- torical context. The social, cultural, and. economic features of the Prudhoe Bay area have undergone dramatic changes in recent years. Most of these changes can be attributed directly to oil development. From a historical perspective, however, some changes have evolved from other forces. Incremental and cumulative effects of act ions such as that proposed herein continue to shape the future of this area and form an important part of the existing environment. Prehistoric traditions of the Alaska arctic coast are the subject of continuing investigations and still very much open to interpretation (Anderson 1979). Preliminary investigations indicate few sites of archaeological significance exist in the Prudhoe Bay area, but reconnaissance elsewhere in the area allows a general outline of prehistoric activities. 3-2 There is a general agreement that peopling of the North American subcontinent began when Asians pursuing game and 'exhibiting the un- restricted wandering patterns typical of large land mammal hunters entered Alaska between 20,000 and 15,000 years ago (Hopkins 1967, 1970; Powers 1973). These hunters utilized the North Slope from the time of entry until about 8000 years ago, and a small wedge-shaped core (Paleo- Arctic tradition) recovered near the Putuligayuk River mouth may indicate they utilized the Prudhoe Bay area (Lobdell 1979b, 1980). The period from about 8000 to 5500 years ago (Northern Archaic tradi- tion) was probably a period of interior-forest and'open-tundra hunting, and possibly fishing. Art if acts include both large 1 an ceo 1 ate and broad, notched projectile points. Tentative evidence of this tradition has been found at Prudhoe Bay (Lobdell 1979b, 1980). Seasonal hunting along the North Slope coasts continued through the subsequent Arctic Small Tool tradition (4000 years ago) from which various artifact types have been recovered. Some later intermediate traditions (Choris, Norton, and Ipiutak) have not been found in the Pnudhoe Bay area, but these cultural manifestations are recognized to have'existed in adjacent regions from recent National Petroleum Reserve-Alaska (NPRA) and trans-Alaska pipeline research. Full-time occupation of cold coasts, large sea mammal hunting, with the continuation of caribou procurement (Thule tradition), began about 1500 years ago. Solidly built permanent dwellings with cold-trap entrances were a notable change from the ephemeral dwelling remains of previous periods. Toggling harpoons of simple styles and other bone tools, as . well as widespread use of ceramics, marked this culture. Recent recon- naissance about 24 km (15 mi) west of Prudhoe Bay located several house ruins that may be of the developmental (Birnirk) phase of this period (Lobdell 1980). This tradition continued up to, and was modified with, the coming of European intrusions. The 17oo•s was a Proto-Historic period in the area. Even though direct contact with the Russians had not occurred in many parts of the Eskimo world, trade goods, including metal tools, were used. North Alaska Eskimos commonly traded for Russian goods with their Siberian counter- parts, using established native trade connections across the Bering Sea and Arctic Ocean. Early 1800 1 s explorations recorded heavy seasonal use of the north coast by Eskimo hunters and fishermen. Intensive trade :contact during this period exposed natives to epidemic diseases, for which they had little immunity, and caused extensive changes in 1 ife-styles. The missionary influence that began about 1890 brought three powerful institutions: western religion, schools, and hospitals. These :institutions thus became powerful within the world of the Inupiat (Worl 19.78). Missionary schools often became a focal point for native population concentrations (Schneider and Libbey 1979). When the reindeer herding and fur markets collapsed during the Depression of the 193Q•s, some families returned to dispersed coastal living. 3-3 Many of these later coastal homes were finally abandoned in the 1940 1 s for centralized locations, such as Barrow and Anatuvuk Pass, where new schools, services, and air-lifted supplies were becoming readily available. Sod house ruins and tent rings at hunting camps from these recent historic phases are still visible along the coast and rivers around the Prudhoe Bay area (Lobdell 1980) (Figure 3.2-1). The Inupi at were quick to adapt technology and institutional changes from outside their culture to meet their own needs (Worl 1978). During the next 20 years, the pressure for this cultural adaptation continued with increasing intensity. In addition to the influences of commerce, religion, and formal education, government activities and programs had significant effects on North Slope natives. U.S. Navy oil exploration in National Petroleum Reserve -Alaska (then Naval Petroleum Reserve No. 4) from 1946 -1953 and construction of a series of Distant Early Warning (DEW) sites between 1954 -1956 provided seasonal employment for many 1 oca 1 residents. Feder a 1 programs provided by the Pub 1 i c Health Service and the Bureau of Indian Affairs, along with subsequent State- sponsored social and economic programs contributed to the need for the native Inupiat to evolve adaptative strategies. Events of the 1960 1 s and 1970 1 s accelerated social and economic changes in the region. Large scale oil exploration in the Prudhoe Bay area began in the early 1960 1 s, for the first time bringing drilling crews and heavy equipment to the area. The presence of large recoverable reserves was discovered by an exploratory well in 1968. During the early 197o•s, field develop- ment began in the area with the construct ion of support fac i1 it i es. After several years of court-imposed delays, Alyeska Pipeline Service Company began constructing the trans-Alaska pipeline in 1974, prompting accelerated development of the Prudhoe Bay field. 3.3 LAND USE The North Slope is the homeland of the Inupiat, indigenous people who have traditionally relied on a hunting and fishing (subsistence) economy (Section 3.14). Inupiat land use patterns have historically centered around resource harvesting activities, with villages situated to take best advantage of the migratory and resident food resources. Some subsistence activities take place over large areas of land and ocean, while others are specific to localized resource sites. These activities are highly variable, shifting between areas according to changes in game and fish movements. Although the population seems centered around traditional communitites, there is a historic and cant inuing use of wide areas of 1 and, year around. Native allotments and remote 11 fish camps 11 (a misnomer since they serve year around and have a much broader purpose than just fishing) often overlap and support a picture of a continued highly developed relationship to the land, and a commitment to subsistence resources as a cornerstone of the Inupiat 3-4 \tump Island 'Gull leland Prudhoe Bay J -~- 1 \ Nfakuk & Iaiande KNOWN ARCHEOLOGICAL SITES AT PRUDHOE BAY PBU Waterflood Environmental Impact Statement Figure 3.2-1 3-5 family and community. Village land use areas for the North Slope, based on resource harvesting associations, are shown in Figure 3.3-1. As indicated, the project area falls within the Nuiqsut and Kaktovik village land use areas. The Prudhoe Bay area is devoted primarily to development of oi 1 and natural gas. Subsistence activities in the area prior to petroleum discovery have largely been displaced. A summer hunting and fishing camp at Beechey Point, some 25 km (15.5 mi) west of the existing causeway, is still in use (L. Ahvakana 1979). Two base camps or operation centers are currently located at Prudhoe Bay. The ARCO camp lies slightly west of the Sagavanirktok River, while the Soh io camp sits in the resource area center near the Putul i gayuk River (Figure 3.3-2). Oil production and transportation facilities occupy 259 km2 (100 mi2) of the Prudhoe Bay area. The facilities are connected by a gravel spine road running northwest to southeast with access roads leading to individual facilities. Camps are strung -out along the road and to the north and east. Organized solely to develop petroleum, the PBU contains no social and governmental institutions associated with typical communities. A third facilities complex called Deadhorse is located immediately south of Prudhoe Bay. This development consists of a State-owned and operated airport and service company base camps, and is the northern term~nus of the supply road from Fairbanks. LAND STATUS Land classification according to owner and status throughout the State of Alaska is currently undergoing dramatic change. Some lands are changing from Federal to State ownership as a consequence of the Alaska Statehood Act (1959) and into native ownership pursuant to the Alaska Native Claims Settlement Act (1971). Lands remaining in Federal owner- ship are currently being reviewed by Congress to determine which public domain holdings should be reserved for particular purposes, such as national parks and national wildlife refuges. The North Slope Borough (NSB), in which Prudhoe Bay lies, encompasses an area of approximately 22.6 million ha (56.5 million acres). As shown in Figure 3.3-3, nearly all of the borough•s land is under Federal or State control. Lands within and adjacent to the Prudhoe Bay area are, except for those discussed below, under fixed State ownership. The State of Alaska has selected approximately 2.4 million ha (3.5 million acres) of land along the arctic coast between the Colville River delta and the mouth of the Canning River. Most of the land is patented State selection, with some lands along the coast tentatively approved State selections (BLM 1979). 3-·6 "'C OJ c =E D) -CD ., ..... 0 0 c. m :::::J < -., 0 :::::J 3 CD :::::J -D) WI -I 3 -....J '0 D) (') ... (JJ -D) -CD 3 CD :::::J - , cS' c: ., CD ~ ~ I _.. I I , ... r-r:-···,l ,....._,. ~ ~ f10PE I ' ... __ .... .. ' ' '~ SOURCE: S. PEDERSEN, NORTH SLOPE BOROUGH, OCTOBER 16, 1978. VILLAGE LAND USE AREAS I LEGEND: -+-WAINWRIGHT KAKTOVIK ---NUIQSUT ATQASUK (ATKASOOK) ------POINT HOPE -···-BARROW -··-ANAKTUVUK PASS •••••••••• PO I NT LAY 'l1 w I ' (X) "0 F :E I» -CD .... -0 0 a. m ;:, < :;· 0 ;:, 3 CD ::l -I» - 3 "C I» 0 -en -I» -CD 3 CD ::l - "TT t@' .... CD (A) (A) I 1\) EXISTING PRUDHOE BAY FACILITIES MAP (APART FROM WATERFLOOD FACILITIES) 0 FACILITIES -PIPELINES 11111111 WELLPADS NOTE: LOCATIONS OF FACILITIES SHOWN ARE APPROXIMATE AND SIZES ARE NOT TO SCALE. / l <! " SOURCE :AERIAL ToPOGRAPHIC MAPS OF PRUDHOE BAY UNIT AREA IIV :AIRI'HOTOTECH.INC. D$oiPIIOfOIIIIIPI>Y:.klly1973 JJ - w I I '-0 "0 llJ c: =e I» -CD "" -0 0 c. m ::I < "" 0 ::I 3 CD ::I -I» - 3 "C I» 0 -(/) -I» -CD 3 CD ::I - 'TI ce· c: "" CD (A) (A I (i.) ARCTIC occ-4 4' LEGEND: D E3 r:::::l l:lill ~ STATE SELECTIONS PATENTED OR TENTATIVELY APPROVED UTILITY CORRIDOR NATIVE VILLAGE WITHDRAWALS VILLAGE DEFICIENCY AREA ~ II D m REGIONAL DEFICIENCY AREA CLASSIFICATION STUDY AREA FDR POSSIBLE ADDITION TO NATIONAL WILDLIFE REFUGE SYSTEM(D-2) NATIONAL INTEREST STUDY AREA FOR POSSIBLE INCLUSION IN THE FOUR NATIONAL SYSTEMS(D-2) CLASSIFICATION AND PUBLIC INTEREST AREAS {a) NOW KNOWN AS THE NATIONAL PETROLEUM RESERVE IN ALASKA (b) NOW KNOWN AS WILLIAM 0. DOUGLAS NATIONAL WILDLIFE RANGE (c) AS OF SPRING 1979. INFORMATION ON CONTINUALLY CHANGING LAND STATUS IS AVAILABLE THROUGH BLM. NORTH SLOPE BOROUGH LAND STATUS (c) ,, t j Approximately 99,462 ha (245,767 acres) have been leased for oil and gas exploration and development within the PBU. One native allotment, which has been approved by Department of Interior and transferred to the Inupi at applicant, covers an area of 1 and apparently near the base of the West Dock at Prudhoe Bay. At present, the Bureau of Indian Affairs and Solicitors Office are assessing a trespass claim by the owner. Under present circumstances the subsis- tence value of the site is hampered by the sizeable development at Prudhoe Bay. Under the terms of the Municipal Entitlement Act (AS 29.18), the NSB may select up to approximately 36,423 ha (90,000 acres) of State land subject to approval by State agencies (Thompson 1980). Figure 3.3-4 shows the locations of tracts nominated for selection by the borough within the PBU. To date, no action has been taken to implement or reject these transfers (Albrecht 1980). LAND USE PLANNING In 1977, the Alaska Coastal Management Act was passed by the State Legislature as an attempt to balance human use of coastal resources with rna intenance of natura 1 systems. It subsequently became part of the Alaska Coastal Management Program that received Federal approval in 1979. A Coastal Pol icy Council was formed to establish standards and guidelines for developing district management programs. Habitats to be managed include offshore areas; estuaries; wetlands and tideflats; rock islands and seacliffs; barrier islands and lagoons; exposed high energy coast; rivers, streams and lakes; and important upland habitat. Of these, all but rock islands and sea cliffs and exposed high energy coast occur in the Prudhoe Bay area. Under the Act, the NSB is charged with preparing a comprehensive coastal management program for the North Slope region. In addition to borough assembly approval, the program must be approved by the Alaska Coastal Pol icy Council. Early in 1980, the borough presented a mid-Beaufort Region District Plan to the Coastal Policy Council. The program covered the area between the Colville and Canning Rivers, including Prudhoe Bay and extending seaward to the 3-mi limit and inland to the 200-ft contour. Its principal emphasis on subsistence activities generated controversy among State agencies and industry. The borough subsequently withdrew its program. As reflected in a new coastal management grant contract, the Borough wi 11 prepare a Coastal Management Program for its entire coastline, including the mid-Beaufort area, and will submit a consolidated program to the State for review and approval by December 4, 1981. In the interim, the NSB adopted a zoning ordinance (Interim Zoning Ordinance Serial No. 75-6-6) establishing a 11 Coastal zone district, .. and 3-10 , .__, PRUDHOE BAY UNIT BOUNDARY JL'J- PRUDHOE rnrlt:~:f};-. BAy ~~S ISLAND NSB NOMINATIONS & SELECTIONS --------, J I I I I I I --~- 1 MILES 0 5 o KILOMETERS 10 NORTH SLOPE BOROUGH NOMINATIONS/SELECTIONS MUNICIPAL ENTITLEMENT ACT PRUDHOE BAY UNIT (a) (a) AS OF MAY 1980 PBU Waterflood Environmental Impact Statement Figure 3.3-4 3-11 four supplemental districts that "merit special attention" including: conservation, geophysical hazard, deferred development, and service base and production (Figure 3.3-5). Uses and activities within each of the supplemental districts are controlled by general regulations as well as by special use permits and stipulations applicable only to that district. The area where the proposed onshore facilities would be constructed is zoned Petroleum Service Base and Production District. Incorporated in the ordinance, but not addressed specifically, are "buffers" along the coast, lakes, streams, and other areas. The purpose of the buffers is to protect critical wildlife habitat and areas where subsistence activities and cultural values are concentrated. Although these buffer areas are not legal entities under the terms of the ordi- nance, any proposed development on these 1 ands would be subject to permits. Extension of the causeway beyond DH 3 would penetrate the buffer area. The ordinance became effective January 2, 1980 and will continue until a borough coastal zone management program and its implementing ordinances are adopted. In 1974, NOAA published regulations establishing procedures for nominat- ing, investigating and managing ocean areas as marine sancturaries (P.L. 92-532). Areas are designated as marine sanctuaries based on conservation, recreational, ecological or aesthetic values with primary emphasis on the protection of natural and biological resources. To date, four areas in the Beaufort Sea have received nominations. The largest, encompassing approximately 207,200 km2 (80,000 mi2), was nominated by Friends of the Earth, Inc. and the Fairbanks Environmental Center. The area follows the coastline from Point Franklin eastward to Banks Island, Canada and extends 161 km (100 mi) offshore. Although NOAA is considering incorporating some Alaska waters for sanctuary designation, no specific areas have been defined and the four Beaufort Sea nominations are not currently considered "viable candidates" (Lopez 1980). 3.4 GEOLOGY AND SOILS Certain aspects of the proposed action will impact the soil and geologic conditions in the Prudhoe Bay area. Description of the surficial and near-surface deposits, particularly gravel, is important with respect to the construction materials required for the project. Offshore surficial sediment characteristics are important to an assessment of gravel availability, dredging impacts, and modifications in coastal processes. Permafrost characteristics relate to terrain sensitivity. The two key mineral resources of the area, petroleum and gravel, would be impacted directly by the proposed action. 3-.12 GEOLOGY The Arctic Coastal Plain onshore of Prudhoe Bay is an area of low relief with numerous shallow lakes and extensive marshy or boggy areas. Most of this plain is underlain by poorly sorted clay, silt, sand, and gravel deposits of the Gubik formation of Quaternary age (Black 1964). This Quaternary unit generally has a maximum thickness of 50 m (164ft) and overltes Mesozoic and Tertiary bedrock. North Slope geomorphology is discussed in more detail by Black (1969), Walker (1973), Hartwell (1973), Sellmann (1975), Cannon (1977), Ferrians (1971), Wahrhaftig (1965), Williams et al. (1977), and Updike and Howland (1979). Coastline in this area is composed of bluffs ranging from 3 -10 m (10 -33 ft) in height and a narrow (<20m, 66ft) beach area. Coarse sediments within the beach material originate primarily from erosion of coastal bluffs and, to a lesser extent, from subsea outcrops that contain coarse material (see Section 3.7, Coastal Erosion and Barrier Island Migration. The predominant offshore bottom material is a Holocene sediment consist- ing. chiefly of poorly sorted silty clays and sandy muds containing varying .amounts of intermixed gravel. Fine sediments are of local derivation, introduced from the major North Slope rivers and by erosion of the coastal bluffs (Naidu and Mowatt 1974). Silts are found both inside and outside the barrier island system. Borehole data from the OCSEAP offshore permafrost program has shown that the fine-grained Holocene sediments extend from .a 3-m (10-ft) thick layer in Prudhoe Bay to a 10-m (33-ft) thick layer 3 km (2 mi) seaward of Reindeer Island. Thickness is largely a function of widely varying sedimentation rates. In Prudhoe Bay, sediment at ion rates of 6 m (20 ft) per 1000 years have been reported (NOAA/BLM 1978). Some areas lack any substantial thick- ness of Holocene sediment. Sedimentation processes are affected by waves, currents, and sea ice that move sediments and modify the bottom (see Section 3.8). Historically, barrier islands have been thought to be products of sedi- ment transport from either offshore or ·longshore sediment sources. However, the origin of these particular arctic islands is uncertain since clastic sediments of the size observed do not appear to be trans- ported in the major river drainage systems (Cannon et al. 1978). Barrier islands located offshore may be recent accumulations of sand and gravel. Studies indicate that these barrier islands in the Beaufort Sea are migrating westward and landward at a relatively rapid pace (Lewellen 1970, Wiseman et al. 1973). Pebble 1 ithology differs from one is 1 and group to another, indicating differences in source material. Several lines of evidence indicate the island chains have or once had their own sediment sources (NOAA/BLM 1978). The western islands of the Jones and Return Islands group is partially blanketed with tundra; sands and gravels make up the eastern islands. 3-14 Boulders are present on the tundra-covered islands, but are noticeably absent from the sand and gravel islands (Naidu 1978). On this basis it is speculated that the tundra islands are relics of breached or drowned shorelines in which topographic lows behind the present islands became submerged, leaving the islands as isolated features. The lack of tundra on the eastern islands may indicate a similar mode of formation with subsequent wave reworking. Naidu (1978) suggests that ice processes may be responsible for obliterating boulders on the eastern islands. It may also be that these islands, during the course of wave alteration, have migrated (probably shoreward). This migration may not have been sufficiently intense to transport boulders. Isolated offshore boulder patches may be due to a similar process whereby the larger clasts are remnants of previous islands. There is little doubt that the islands are elongating, predominantly through spit formation to the west. Estimates of rates of spit growth vary between 2 m/yr (7 ft/yr) (Naidu 1978) and 6 m/yr (20 ft/yr) (Wiseman et al. 1973). Their shorelines and nearshore features are continously changing. The tundra-blanketed islands appear, at the present time, to be eroding from both the north and south sides (Cannon et al. 1978). SEISMOLOGY Prudhoe Bay is within Seismic Risk Zone 1 of the Uniform Building Code The risk of the project area being affected by a significant (>5.0 Richter Magnitude) seismic event is therefore low. Arctic coast seismic data is only available for the last 10 years and additional time will be needed before recurrence rates based on this data become valid indicators of future activity. Alyeska Pipeline Service Co. used the following ground motion parameters for design of facilities in the Prudhoe Bay area: maximum contingency level acceler- ation of 0.12 g, maximum contingency level velocity of 15.2 cm/s (6 in/s), maximum operating level acceleration of 0.06 g, maximum operating level velocity of 7.6 cm/s (3 in/s), and a duration of 5 s. A contin- gency level event was defined as approaching the maximum credible event for the area and facilities were designed to deform, but not rupture during this event. The-operating level event was defined as an event with a return period similar to the project life and facilities were designed to withstand such an occurrence. SUBSIDENCE Subsidence in the region is believed a remote possibility. No govern- ment or industry monitoring program for regional subsidence is known to exist. • 3-15 MINERAL RESOURCES Only two significant mineral resources are found in the vicinity of Prudhoe Bay. These are hydrocarbons and gravel (which is considered a surface resource). The Prudhoe Bay oil field covers several hundred square miles immediately south and west of Prudhoe Bay. Estimates of recoverable reserves approach 10 billion bbls, and future drilling will add reserves until the ultimate field potential could reach 15 -20 billion bbls (Brent and Goldberg 1970). Oil is present in three main producing format ions: the deep Lisburne 1 imestone, the Sadlerochit sandstone, and the shallower Kuparuk River sands. Vast quantities of gas are present as a free gas cap in at least two of the Prudhoe Bay reservoirs. Estimates of recoverable gas reserves are variable although most studies agree on a current estimate of 736 billion m3 (26 trillion ft3). The 1 argest exposed onshore deposits of sand and gravel in the project area are the floodplains and active river channels of the Kuparuk, Putul igayuk, and Sagavanirktok Rivers. Other potentially exploitable deposits exist beneath thaw 1 akes, at the surface in some beach areas (the product of bank erosion), and at or near the surface on many of the offshore islands. An important offshore gravel resource that can be developed by deep mining are the buried Pleistocene valleys. Existing and proposed gravel sources are shown on Figure 3.4-1. PHYSIOGRAPHY The project area lies in the Teshekpuk Lake section of the Arctic Coastal Plain of northwestern Alaska (Walker 1973) (Figure 3.4-2). As shown below, the area is characterized by a uniformly flat terrain sloping gradually north to the Arctic Ocean. Gentle, poorly defined surface undulations are caused by patterned ground, o 1 d drain age chan- nels, thaw lakes, and other depositional, erosional, or permafrost related features, including pingos, which are hills with an ice core. Polygonal or patterned ground is the most conspicuous surface feature. Temperature-induced contraction cracks are formed in polygonal patterns similar to those encountered on dry mud flats. These cracks fill with water and freeze. Continued cracking, filling, and freezing along the same 1 ines eventually forms a network of ice wedges that sometimes become sever a 1 meters deep and are generally spaced tens of meters apart. In time the ice wedges form troughs bounded by ice push ridges. Trough ridges and undisturbed central areas are referred to as ice-wedge polygons. Using a highly simplified representation, thaw lakes usually originate from small, shallow ponds that generally begin in low-centered polygons or at the intersect ion of ice wedges (Sellman et al. 1975). Other nearby ponds expand and coalesce to form larger ponds and lakes. During the summer period, the underlying permafrost is thawed and allows 3-16 w I ...... -....J "'0 9 =E I» -CD .., -0 0 a. m ::l < :::;· 0 ::l 3 CD ::l -I» 3 '0 I» (") -en -I» -CD 3 CD ::l - 'TI cg· .., CD (A) :.:. I ...... k::::l EXISTING GRAVEL SOURCES 0 FACILITIES -PIPELINES 11111111 WELLPADS NOTE: LOCATIONS OF FACILITIES SHOWN ARE APPROXIMATE AND SIZES ARE NOT TO SCALE. I EXISTING AND PROPOSED PRUDHOE BAY GRAVEL SOURCES IIOUAC! : A!IIIAL TOPOGRAPHIC MAl'S OP I'RUDHOE IIIAY UNIT AIIEA IV : AIR I'HOTO TECH, INC, o .. oiPI.........,:.kllf1173 ,,,J ~ I w I ........ co ""0 m c :E S» -CD ... -0 0 c.. m :::l < -· ... 0 :::l 3 CD :::l -S» --3 "0 S» 0 -en -S» -CD 3 CD :J - "TT i5' c: ... CD (A) ~ I 1\) >o' ... 152' I c 0 Wainwright Physiographic Units Interior Plains Arctic Coastal Plains ~ Teshekpuk [I]J1j] White Hills Rocky Mountains Arctic Foothills [::,~::::-_:'"1 No,lhern Foothills ~ Soulhern Foothills Arctic Mountains c=:;J De Long Mountains [}::/]] Noatak Lowlands l·:~·.~>~:::J Baird Mountains c 146 E AN Kilometers s'e' Cl .. o s3"' 58 lbo Drainage Areas A--Northweslern B --Northern (--Colville D--Eastern C=:J Central and Eastern Brooks Range PHYSIOGRAPHIC PROVINCES, DRAINAGE REGIONS, & KEY LOCATIONS OF THE NORTH SLOPE , \ James E. Hemming The formation of low-centered and high-centered polygons are brought about by a complex of natural forces in- cluding ice formation and erosion. This landscape pattern is common in the Prudhoe Bay area. deepening and enlarging of the small lake. As the lake expands, it joins with others and becomes deep enough to maintain a thaw bulb. Because thaw lakes are largely unstable with active erosion at basin margins, lake basins often coalesce and drain. The thaw lake cycle consists of repetitive stages of lake formation and ultimate drainage and is the primary geomorphic process that modifies the land surface. Nested and overlapped drained basins contribute most to topography, drainage, and wetland distribution. SOILS Tundra soi 1 s predominate in the project area, typically covered with a mat of vegetation on the order of 20 em (8 in) thick. Beneath the mat is usually a surface black organic silt horizon underlain by a dark, gray-brown, frost-altered silt and then by permafrost. Using the Unified Soils Classification System, the near-surface soils (including the shallow permafrost) are generally ML (Silts, Fine Sandy Silts, and Clayey Silts). They are generally non-acidic to calcareous. These soils pose severe construct ion problems since they are highly suscep- tible to heaving and settling during freezing and thawing, respectively. --- 3-19 Within the onsite tundra soils, the seasonal thaw (active) layer typi- cally ranges from 0.5-1.5 m (2-5 ft). Most active layer soils have a low permeabi 1 ity and stay saturated throughout the thawed season. Even when thawed, the soils are too cold to allow cultivation. Load- carrying capability is low to moderate if the active layer thickness is maintained. If the thermal equilibrium is destroyed and permafost thaws beneath a foundation, severe settlement and support loss can occur. Permafrost is any substance that exists at a temperature of less than 0°C (32°F) for 2 or more consecutive years. If salt is present, perma- frost can have both a solid and a liquid state of water. Onshore permafrost is continuous throughout this part of Alaska and has been penetrated to depths of 650 m (2133 ft) (Stonely 1970). In holes drilled on land, permafrost temperatures as cold as -5°C (23°F) have been measured. The near-surface permafrost throughout the project area is generally ice-rich, containing observable free ice. Onshore perma- frost can contain 40 percent ice content by volume (Gold and Lachenbruch 1973). In general, subsea permafrost is usually warmer and more saline and more easily disturbed than onshore permafrost. Subsea permafrost is usually relict (left over from colder geologic periods) and probably slowly melting in place because of shoreline erosion and exposure to seawater. Offshore ice-bearing permafrost is located at widely varying depths. Near shore it may be only a few meters below the sea bottom whereas farther offshore it may drop to depths of 90 -150 m (295 -492 ft) and may even be absent at some locations. 3.5 VEGETATION Plants, by virtue of their ability to use the sun's energy to synthesize organic compounds, provide the energy base upon which other living components of an ecosystem depend. Net primary productivity is a measure of this base and is therefore an excellent general criterion to judge environmental effects. In addition, plant 1 ife, in conjunction with topographic and micro-relief features, provides the structural habitat that many animals require and is the basis for vegetation patterns. The characteristics of the vegetation in a particular area determine, in 1 arge part, the distribution and abundance of the asso- ciated animals and are of primary importance in analyzing impacts resulting from terrain disturbance. The ecology and distribution of vegetation characterizing the North Slope in general and/or the Prudhoe Bay area in particular have been described in detail in a number of documents (U.S. Army Corps of Engineers unpublished, Walker et al. in press, Tieszen 1978, U.S. Department of Interior 1978, Johnson 1969). The reader is directed to these documents for supplemental technical information. 3-20 GENERAL DESCRIPTION The area to be affected by the proposed action lies on flat, poorly drained terrain characteristic of the North Slope. The primary vegeta- tion type has been described as 11 wet tundra 11 because of the saturated soil conditions and standing water exhibited during the thawed season. Plant 1 ife consists primarily of small plants with low growth form. Species diversity is low and growth is slow relative to areas south of the Brooks Range. Severe weather conditions, a short growing season, limited nutrient availability, and cold soil temperatures all act to limit production. Because of the slow rate of decomposition, energy and nutrients tend to remain bound up as dead organic matter both above and below the ground surface. Net primary productivity, nutrient release, and energy flow rates increase with site moisture. Thus, landscape units that are more wet generally will make a greater contribution to overall ecosystem productivity (Webber 1978). Although productivity of the Arctic Coastal Plain vegetation community is low relative to more southerly areas, the existing level of productivity is, nevertheless, crucial within the context of the coastal plain ecosystem. Although coastal plain vegetation may appear uniform, it is composed of a mosaic of micro-habitats each characterized by somewhat different vegetation. Thaw lake formation and drainage, combined with polygon formation, as described in Section 3.4, cause elevation differences of up to several meters, resulting in soil moisture ranging from deep standing water within thaw 1 akes and depressed polygons to relatively dry terrain on the raised rims or centers of polygons. Vegetation varies correspondingly. Emergent grasses are typical of standing water micro-habitats and moderately wet areas. The driest sites contain grasses and sedges plus woody shrubs and lichens (Everett et al. 1978). The most common microhabitat, covering 40 percent of the wet tundra, is characterized by saturated soils and growths of sedges and grasses (U.S. Army Corps Engineers, unpublished). A number of more 1 imited habitat types occur in the Prudhoe Bay area, several of which are of particular importance. One of these is the salt marsh/beach zone abutting the Beaufort Sea shoreline where brackish marshes have formed in protected coastal areas and within drained 1 ake basins connected to the sea. The vegetation of such areas is character- ; zed by salt to 1 erant species. Another habitat type is present on the gravel floodplains or sandy deltas of major rivers where vegetation is sparse and characterized by woody shrubs or pioneer species. Pingos, river bluffs, and other special land forms are characterized by plant communities that are atypical of the moist tundra as a whole. Another 11 habitat type 11 has been artificially created by extensive gravel fill areas created during oi 1 development. These elevated roads and work- pads, which are similar to those to be built under the proposed action, are generally unvegetated. The barrier islands immediately west of the West Dock (Stump Island, Egg Island, and Long Island) are largely devoid of vegetation (Gavin 3-21 1 1976). However, some of the barrier islands farther to the west are covered with typical tundra plants. One plant species in the Prudhoe Bay area has been proposed for inclu- sion as a threatened species under the Endangered Species Act of 1973 (Murray 1980a). This species, Thl aspi arcticum, has been found at one 1 ocat ion on a grave 1 terrace of the Kuparuk River, south of the existing Kuparuk River bridge (Murray 1980b). VEGETATION MAPPING/HABITAT EVALUATION The most comprehensive system to classify, map, and evaluate Prudhoe Bay vegetation and habitats has been developed by the Institute of Arctic and Alpine Research (INSTAAR) in cooperation with scientists at the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) and Ohio State University. The mapping effort considered a combination of related mapping elements. Landform units, soils characteristics, and plant communities were combined in the product ion of detailed master habitat maps (Everett et al. 1978). Substantial portions of the Prudhoe Bay development area were mapped according to this system prior to the Waterflood Project app 1 icat ion. In add it ion, a specific study was initiated in relation to the Waterflood Project. CRREL scientists, in conjunction with Corps• personnel and consultants, expanded the CRREL mapping system to include zones around each area where terrain disturbance is anticipated. A ser.ies of thematic maps (Appendix L), each considering a different aspect of habitat value or sensitivity, were derived from the master map and verified by field ground truthing during the summer of 1980. VEGETATION RESOURCE VALUE AND SENSITIVITY A detailed description of the vegetation in and near waterflood facil i- ties is shown on the Appendix L master maps. Further discussion of the value of the various plant assemblages to wildlife and the relationship of assemblages to wetlands is described in Sections 3.6 and 3.7, respectively. The habitat evaluation method described in Appendix L analyzed the relative rates of primary productivity (i.e., the rate at which a plant community produces organic matter over and above that required to maintain its metabolic requirements) for the plant communities in the vicinity of proposed project facilities (see Figures L-40 through L-73). Another habitat element that is especially applicable to an analysis of impacts from the Waterflood Project is the sensitivity of plant commu- nities to spills of saltwater. Appendix L graphically presents this sensitivity for the west pipeline/road corridor. 3-22 3.6 WILDLIFE Wildlife have long been valued as a source of food and clothing in arctic regions. The abundance and diversity of animal life within a particular area is an indicator of the area • s ecological health and provides insight into the impacts of man•s activities. The fauna of the Arctic Coast a 1 Plain and the Prudhoe Bay area have been described in numerous reports (Brown 1975, U.S. Army Corps of Engineers unpublished, U.S. Department of Interior 1978, Bergman et al. 1977, Gavin 1974). As is typical of far northern regions, animal diversity and productivity is generally low and most activity is limited to the short thawed season. Despite low productivity, some animals are seasonally abundant and the Arctic Coastal Plain provides essential habitat for a number of species. Seasonal migration is a critical aspect of life history for many arctic animals. Figure 3.6-1 illustrates the international movements characteristic of several key species. BIRDS Because of the difficulty in separating birds of the terrestrial environment from those of the marine environment, both groups will be discussed in this section. Many of the birds occupying the Waterflood Project vicinity are water-oriented and uti 1 i ze both freshwater and nearshore marine areas. Birds are particularly important members of the Arctic Coastal Plain fauna for the following reasons: -- The Arctic Coastal Plain is the primary breeding ground for several species of waterbirds (snow goose, king eider, red phalarope). ' Most species migrate long distances to breed in the Arctic; .therefore, events occurring on the breeding grounds may ultimately impact ecosystems far removed from Prudhoe Bay. Furthermore, many are subject to international treaties and regulations. Waterfowl are culturally and economically important because of their value as a subsistence and recreational resource. Waterfowl that breed in the Arctic are harvested as far south as South America. Birds are one of the major consumers, thus providing an important energy link in the arctic food web. 3-23 ~I "'tJ OJ c ~ S» -CD ""'' -0 0 a. m ::::J < ::;· 0 ::::J 3 CD ::::J -S» - 3 "0 S» (") -en -S» -CD 3 CD ::::J - ., 10' c:: ""'' CD (A) 0> I ..... I I I MIL.ES 0 50 100 KILOMETERS 1-! 0 100 200 / I I \ c. H UK CHI ' KEY: 111111111111111 ARCTIC FOX ........... ,,,,,,,,,,,,,,,,,,""~'? CARIBOU ---POLAR BEAR ••••••••• OLD-SQUAW BLACK BRANT & COMMON EIDER -·-PINTAIL ---PECTORAL SANDPIPER ___ , SANDERLING ... I I BEAUFORT ... --------.. Prudhoe Bay -~ _R_ C T I C C I R C L E -----------,-- 11 II ALASKA !i ':-0 --- MIGRATORY BEHAVIOR OF SELECTED PRUDHOE BAY ANIMAL SPECIES .._. ..... BOWHEAD WHALES Since birds are abundant and conspicuous, they represent a readily observable indicator of habitat quality. Bird activity is a seasonal phenomenon on the arctic coast. Abundance varies from an occasional raven, ptarmigan, gull, or snowy owl in winter to an influx of thousands of waterfowl and shorebirds from May through September. Pitelka (1974) concluded that greatest diversity of water- fowl on the Alaska Beaufort Sea coast occurs in the central sector extending from the Canning River westward to the Colville River. Bergman et al. (1977) documented 25 species of breeding birds within their Point Storkerson study area with densities as high as 280 birds per km2. The addition of non-breeding birds would add considerably to this figure. Summer residents are dominated by wading and swimming birds that use a combination of terrestrial, freshwater, and marine habitats. The only regularly breeding passerine birds are Lapland longspurs and snow buntings EBailey 1948, Bergman et al. 1977). The most concentrated waterfowl use occurs at river deltas, in the estuarine waters inside the barrier islands, and on the larger ponds or lakes surrounded by emergent aquatic vegetation. Sandpipers and phalaropes are the most abundant shorebirds and occur on gravel bars, beaches, and sedge-grass marshes (Bergman 1974). Whistling swans, arctic loons, red-throated loons, oldsquaws, eiders, pintails, white- fronted geese, lesser Canada geese, and brant are the most common waterfowl (Bergman 1974, Gavin 1974). Offshore islands are used primarily by glaucous gulls, arctic terns, and common eiders. The islands are also used as nesting habitat by oldsquaw and eiders. According to Johnson (1979a), the density of typical barrier island nesting birds was higher on gravel or sand-covered islands than on tundra-covered islands. Islands at the mouth of the Kuparuk River have nesting colonies of brant. Howe Island at the mouth of the Sagavanirktok River supports the only snow goose nesting colony on Alaska's arctic coast (Gavin 1976). Lagoons occurring shoreward of the barrier islands are important as molting and feeding areas for oldsquaw as well as other waterfowl and shorebirds. In late summer, many species inhabiting lakes during the nesting period move to coastal lagoons. More turbid, unprotected sites, s·uch as Harrison Bay, support reduced numbers of waterfowl (Johnson 1979a). Thousands of shorebirds use the lagoons and seaward barrier island beaches as staging areas prior to fall migration. Oldsquaw numbering in the tens of thousands inhabit the Simpson Lagoon/Gwydyr Bay area after breeding and during the molt in late summer and fall (NOAA-BLM 1978). Oldsquaw breeding in both Canada and Alaska contribute to these post-breeding concentrations. Marine invertebrates that seasonally invade the lagoon habitats provide an important food source for birds using such areas. - 3-25 Open-water areas outside the barrier islands are low in densities and numbers of birds. Non-breeding jaegers, murres, and non-breeding gulls dominate the offshore areas, with gulls being most common (Watson and Divoky 1974, Divoky 1979). Only one endangered bird species, the arctic peregrine falcon, occurs in the general area, but the nearest nesting area is more than 32 km (20 mi) to the south at Franklin Bluffs on the Sagavanirktok River (Hemming and Morehouse 1976). The onshore portion of the proposed project area contains substantial areas of high quality waterbird habitat. The USFWS has attempted to classify wetlands in the Prudhoe Bay vicinity according to their value to birds (Bergman et al. 1977). The USFWS study area included a variety of the region's major wetland types adjacent to the coast and northern edge of the oil field and, therefore, has particular application to environmental assessment of the proposed action. Bergman et al. (1977) and Derksen et al. (1979) found that certain kinds of wetlands were particularly valuable to waterbirds, specifically large lakes or drained-lake basin complexes that contain abundant growth of the emergent grass species, Arctophila fulva. Coastal wetlands were also considered important. Other wetlana types were used by birds but use was less concentrated than in the Arctophil a types. Furthermore, the Arctophila types are much more limited in area than the typical wet sedge-meadow type. Waterflood facility locations were mapped and habitats classified according to their value to birds. The classi- fication system· relied heavily on the Bergman system aided by a key developed by USFWS to translate the master habitat maps into waterbird values. The overall habitat value/sensitivity maps in Appendix L reflect bird habitat values. It can be seen from these maps that waterflood project sites are often in close proximity to high value bird habitats. Existing area development includes roads, surface pipelines, drill pads, oil wells, gravel pits, docks, airfields, and camps (Section 3.3). Within the existing oil field, Connors and Risebrough (1979) estimated roughly 10 km2 (4 mi2), or 3 percent, tundra habitat loss has occurred to date from which they extrapolated a total displacement of about 1000 -2000 pairs of shorebirds. The latter figures provide some indication of the impact to date on one group of birds in the Prudhoe Bay area resulting from direct habitat withdrawal. If it is assumed that all suitable habitat is used by breeding birds, local shorebird populations can be expected to have decreased by an amount proportional to the habitat lost. Alternatively, the birds may have been displaced into lower quality habitat, in which case local populations would be reduced by an amount somewhat less than the percentage of habitat lost. Additional displacement of shorebirds was also documented by Connors and Risebrough as a result of the effects of dust, noise, and activity. 3-26 Existing road and pipeline systems have altered surface water patterns in some areas by directly intercepting surface groundwater (sheet) flow. According to Connors and Risebrough (1979), such changes have impacted bird nesting density and habitat by altering plant species composition and lowering the percent of plant cover. Vegetation alterations have also occurred where the predominant northeast winds carry dust from gravel roads. A related phenomenon occurs when dust covers snow in adjacent areas causing earlier than normal spring snowmelt and attracting migrating waterfowl and other birds until areas farther from the road system thaw (Klein and Hemming 1976). It is not known whether this early melt phenomenon has represented a positive or negative impact on waterfowl; however, it is not believed to be significant. Early access to plant cover may be advantageous. On the other hand, concen- tration of birds within a potentially hazardous industrial area could be detrimental. As an indirect result of Prudhoe Bay development, arctic foxes have been attracted to camp areas where waste food materials are sometimes available, resulting in abnormally high predation on local nesting birds (Norton et al. 1975). Improved waste handling procedures in recent years has probably improved this situation as indicated by somewhat lower fox populations (Hanson and Eberhardt 1979). Ruddy turnstones and glaucous gulls are both preferential garbage foragers and Connors and Risebrough (1979) reported that they occur in higher densities wherever garbage is more abundant in the Prudhoe Bay _area. In existing man-made habitats such as the PBU West Dock, Connors and Risebrough (1979) found that zooplankton feeders such as terns, gulls, and phalaropes use the pier habitat 11 in preference to natural mainland shores... However, this area has a greater exposure to other perturbations. MAMMALS Mammals known to occur in the Prudhoe Bay area include shrews, voles, lemmings, arctic ground squirrels, caribou, arctic fox, wolf, wolverine, least weasel, grizzly bear, and polar bear. Of the above species, only a few are of special concern when examining potential impacts of the proposed action. Small mammals, particularly lemmings, are uncommon in the Prudhoe area compared to other North Slope areas (Feist 1975). The most abundant and important large mammals are the caribou and arctic fox. Another mammal of special interest is the polar bear. The habitat evaluation program described in Appendix L included an assessment of mammal habitat values. These values were included in the assessment of overall habitat value. 3-27 • Caribou The caribou has special significance both because of its value as a subsistence and recreational resource, and because it is the only large herbivore in the arctic coastal region and is an important part of the food web. Because of migratory movements that may extend as far as Canada, caribou can be considered an international resource. There is good indication that caribou may be a sensitive indicator of the effect of man•s activities. In recent years, a number of caribou studies have been initiated in the Prudhoe Bay area to assess oil field development and trans-Alaska pipeline construction impacts (Child 1973; White et al. 1975; Cameron and Whitten 1979a,b; Cameron et al. 1979). Consequently, knowledge of caribou habitat requirements is increasing rapidly, especially as it relates to actions such as that proposed herein. Caribou are common on the North Slope and are frequently seen in the Prudhoe Bay area, especially in the summer. It was originally thought these animals belonged to the Western Arctic or Porcupine herds. These are large herds ranging widely in the area whose ranges apparently meet near Prudhoe Bay (Hemming 1971). Evidence (Cameron and Whitten 1979a) suggests the presence of a small subpopul at ion of about 5000 resident caribou on the North Slope whose distribution is roughly centered on the trans-Alaska pipeline. This 11 Central Arctic 11 herd generally winters in the northern Brooks Range foothills, moving to areas near the arctic coast in the spring and summer. In some years, a port ion of the herd (up to 300 animals) has remained in or near the Prudhoe Bay area through the winter. Major calving activity is thought to occur near the coast between the Colville and Canning Rivers in early June (Cameron and Whitten 1979a). Calving was noted in the Prudhoe Bay area in the early 1970•s, but apparently has decreased in recent years with calving now occurring both east and west of Prudhoe Bay (Cameron et al. 1979, Cameron and Whitten 1979b, Gavin 1977). Caribou use coastal areas primarily during June, July, and August. During this time, east-west movements adjacent to the Prudhoe Bay oil field are relatively common (Gavin 1977). While caribou are frequently observed within and near the oil field, there is considerable statistical evidence that some animals are avoiding the area (Cameron and Whitten 1978, Cameron et al. 1979). The authors suggest that cows in 1 ate pregnancy and cows with calves actively avoid zones of human activity. Furthermore, movement within more densely developed portions of the field has been reduced (Cameron 1980). East-west caribou movements during the summer are common on either side of the Prudhoe Bay complex, but they no longer extend through the oil field to an appreciable degree. Numbers of the Central Arctic herd have increased since 1977. The increase in calf production and survival coincides with a series of mild winters in the late 197o•s and the almost total eradication of the area•s wolf population. The 3-28 increase in the herd•s population since 1977 is estimated to be 1000 - 1500 (Alaska Department of Fish and Game 1980). Therefore, despite the potential adverse impacts that the TAPS line and the Prudhoe Bay complex may have had, it appears that the short-term effect may not have been great (see State of Alaska comment, Vol. 3). However, habitat modifi- cations and disturbance caused by expanded North Slope oi 1 and gas development may affect regional caribou populations in the long term. While occupying the coastal zone, caribou feed on a variety of plant communities. White et al. (1975) found some evidence that caribou fed more on the higher, drier habitats characterized by heath vegetation and avoided the sedge-marsh areas. However, this behavior may be related more to insect harassment than preference for particular forage species. The above authors cone 1 uded that the Prudhoe Bay area was moderately productive in terms of value as caribou range. The coastal zone provides additional value to caribou as a refuge from insect harassment due to the prevailing winds. Arctic Fox The arctic fox has value as a fur bearing animal and may have additional significance in relation to environmental impact because of its tendency to modify its behavior in the presence of man. The arctic fox is a common year-round resident of the Arctic Coastal Plain and the most conspicuous Prudhoe Bay area predator. · In 1972, Underwood (1975) located eight dens in the vicinity, two of which were on Point Mcintyre, just west of the West Dock. Arctic foxes are often attracted to human activity by possible food availability. There is some indication that fox populations have remained high in the project area despite low natural food levels in some years (Battelle Pacific Northwest Laboratory 1979). Artificial food sources apparently have enhanced survival rates and altered normal foraging patterns. Natural foot!s of arctic foxes include lemmings, birds, bird eggs, some kinds of plant material, and carrion (Underwood 1975). Foxes are highly mobile and may move distances in excess of 1000 km (622 mi) on the sea ice during the winter (Eberhardt and Hanson 1978). Periodic rabies epidemics occur within northern fox populations. During an epidemic, a large proportion of foxes become carriers of the disease, and may attack humans. Po 1 ar Bear Although polar bears are uncommon throughout their range, they are specifically mentioned in this section because of public interest and because their narrow habitat requirements make them vulnerable to disturbance. The circumpolar distribution of these bears and an inter- national treaty make them an international resource. 3-29 Polar bears occur throughout the Beaufort Sea pack ice, but are most abundant in areas where currents or winds keep ice in motion, resulting in many open leads. Bears are attracted to such areas by the avail- ability of sea1s, their primary food. Although the Prudhoe Bay region is of 1 ittle importance for polar bears, tagging studies in which bears were marked and recaptured off the coasts of Alaska and northwestern Canada indicate that bears that occur in the Beaufort Sea north of Alaska form a somewhat discrete population experiencing only a limited amount of interchange with other A 1 ask a bears to the west and with Canadian bears to the east. Much of the denni ng for the Beaufort Sea population of bears north of Alaska occurs in a strip along the Alaska coast inland for 40 km (25 mi) and offshore to the edge of the shorefast ice. This denning zone extends from the Canadian border west to Point Barrow and then southwest toward Point Lay. During winter months, female polar bears seek out suitable sites for denning. Female bears give birth to young in winter snow dens, and maintenance of undisturbed denning areas is especially critical for maintenance of polar bear populations. More dens and newborn cubs just out of dens have been found between the mouth of the Colville River and Flaxman Island than elsewhere along the coast. The most important bear denning habitat within the Prudhoe Bay region lies within a 16-km (10-mi) zone along the coast and consists of river drainages having stream-cut banks which can accumulate snow to depths in excess of 3m (10ft). The barrier islands also provide denning habitat during the winter. Cross Island, in particular, provides good denning opportunities {Alaska Department of Fish and Game 1980). Polar bear sightings are uncommon within the Prudhoe Bay area. Gavin {1974) reported a single animal near Cross Island in 1971. Two females with cubs were seen at North Star Island and Oliktok Point in 1972, and a lone bear was observed just east of the ARCO base camp in 1973. The most recent sightings were in the vicinity of Duck Island --a single animal was observed during the winter of 1977-1978 and a sow with two cubs was observed in November 1979 (Meehan 1980b). The only inland record is a female killed by an Eskimo on the west fork of the Sagavanirktok River in 1944 (Bee and Hall 1956). 3. 7 WETLANDS It has been nationally recognized that wetland habitats are a particu- 1 arly valuable ecological resource and an integral part of regional hydrological regimes. Because of these special values and vulnerability to development activity, wetlands were granted special regulatory status via Section 404 of the Clean Water Act of 1977. This act delegates authority to the Corps and EPA to manage wetland alteration activities through a permit system. Wetlands are treated as a separate section in this report in order to achieve emphasis commensurate with these special values and regulations. Wetlands are defined by regulations (33 CFR 323.2 Para. c) as follows: 3-30 11 those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support and that under normal circumstances do support a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs and similar areas ... Much of the Arctic Coastal Plain is characterized by wet soil conditions and hydrophytic vegetation and, therefore, has been considered wetland from a regulatory standpoint. However, separation of wetland from non-wetland on the coastal plain has been difficult because there is a continuum of moisture conditions that often exists over a distance of only a few meters and with changes in relief of only a few centimeters. This condition of micro-relief and the small dimension of vegetation units results in a very compressed mosaic best delineated on large scale photo~r-aphy. Although the coastal plain vegetation can be divided ·into numerous micro-habitat types, even the driest types may have saturated soil during the early summer thaw. The Corps' Alaska District issued a public notice of 12 January 1979 11 asserting interim jurisdiction for work in 'wet tundra' areas on the North Slope of Alaska.11 Such wet tundra areas include large portions of the coastal plain and the entire Prudhoe Bay area. The Corps sponsored a study of North Slope wetlands (unpublished) in an attempt to delineate wetlands more accurately and on a finer scale. The Corps, in consultation with USFWS and EPA, has classified wetland and non-wet 1 and for the primary effect area. Wet 1 and areas for a 11 project sites relating both to 404 permit jurisdiction and to ecological characteristics are defined and illustrated within Appendix L (Figures L-2 through L-35). WETLAND VALUES A quantitative and qualitative approach was taken t'o assess the values of wetlands and judge the performance of alternative actions for the proposed Waterfl ood Project. Based on 1 egis 1 at ive requirements, policies, Corps' regulations, scientific analysis, and the guidance of other agencies, wetland values on the North Slope are vie~1ed in four broad categories. The following is a discussion for each of the value categories along with their related criteria used by the Alaska District to assess the environmental effects of the proposed Waterflood Project (Chapter 4.0). Food Chain Production As indicated in Section 3.5, net primary productivity increases with soil moisture. The highest production occurs within pond margin communities (Webber 1978). This relatively high productivity is related to the higher rate of decay of organic matter and the consequent release of nutrients that occurs on wet sites. Wetland communities, therefore, 3-31 provide a disproportionate amount of total ecosystem productivity. There is evidence that wetter sites also contain a higher biomass of invertebrate consumers as would be expected from the higher primary productivity (MacLean 1975). Wetlands ~Jith standing water provide a substrate for aquatic invertebrates. Bergman et al. (1977) found substantial populations of aquatic macro-invertebrates, such as insect larvae and small crustaceans, especially in wetland types classed most important to waterbirds. The Prudhoe Bay wetlands, therefore, supply an valuable link in one of the more important food web pathways by supporting large invertebrate populations that, in turn, help support the abundant waterbirds. In addition, a variety of predators, including arctic foxes and peregrine falcons, feed on waterbirds or their eggs. The primary productivity of wetland habitats also enters the food web through other pathways. For example, caribou feed directly on lush emergent vegetation to supply the energy needed to sustain their 1 arge mass. Habitat for Land and Aquatic Species The importance of wetland as waterbird habitat has been discussed in Section 3.6. Use of the Prudhoe Bay wet 1 ands by other vertebrates is limited. Fish may be found in the few wetlands that are connected directly to the ocean or streams. Birds and bird eggs are an important seasonal food for arctic foxes; therefore, these animals are often associated with wetland margins for part of the year. As discussed in the previous paragraph, wet 1 ands a 1 so provide important habitat for a variety of invertebrates. Another assessment criteria, therefore, relates to the ability of wetlands to continue to support these animals following development of the Waterflood Project. Hydrology and Water Quality The North Slope wetlands serve an important hydrological storage function. Because of the underlying permafrost, water reaching the land surface as snow or rain is retained on the surface. During the thawed season much of this water is stored within wetlands. Therefore, in spite of very low precipitation (about 13 cm/yr, 5 in/yr), a wet environment is maintained. Extensive wetland storage in the area moderates surface runoff and stream flows (Brown et al. 1968) and thus reduces the possibility of erosion. Indeed, surface water flow patterns are often difficult to define and may be represented only by inter- connecting wet 1 ands. Drainage patterns on a site-specific basis are important in maintaining the naturally occurring mosaic of habitat types. The existing development has interrupted these patterns in many locations and has caused pending over substantial areas as indicated on the master habitat maps within Appendix L. In some cases, areas disturbed by pending have exceeded the areas of gravel fill. Chemical reactions that occur within the wetland environment may affect water quality and have regional ecological implications. As discussed above, the relatively high rate of decay that occurs within the organic 3-32 matter underlying wetlands accelerates the exchange of materials between water and sediment and may release nutrients into an environment that is generally nutrient poor. Relatively nutrient 11 rich 11 water originating in wetland communities may be carried by surface drainage into lakes, streams, and eventually the Beaufort Sea. River runoff provides a source of nitrogen to the marine environment (Schell 1974) and it is likely that this nitrogen is primarily of tundra origin (Schell 1980). Interconnecting wetland complexes would be expected to be most signi- ficant to this nutrient pathway. Subsistence and Recreational Use Prior to the discovery and development of major oil reserves, wetland·s in the Prudhoe Bay area were used for subsistence hunting (Section 3.14) by the Eskimo. Development at Prudhoe Bay has served to displace subsistence use of these wetlands areas to the east towards Kaktovik and to the west towards Nuiqsut. The primary human activity currently occurring within the Prudhoe Bay area is related to oil development. With most elements of the human population being transient, traditional use of wetland areas is now limited. Waterfowl hunting, a traditional wetland use, is not currently available to Prudhoe Bay residents due to industry regulations. However, the waterfowl of the area do migrate and are harvested by people from Barter Island, Nuiqsut, Barrow, the northwest coast, and many other areas of the United States, Canada, and to some extent, South America. Although the aesthetic aspects of wetlands and their associated animal life are undoubtedly valued by many current residents of Prudhoe Bay, the recreational potential in Prudhoe Bay is very limited because of the short season, adverse weather conditions during the ice-free season, and the unpredictability of fish runs. Most public interest in the area is connected with visiting the oil facilities. 3.8 PHYSICAL AND CHEMICAL OCEANOGRAPHY Physical and chemical oceanography is a major factor in determining the biological diversity and level of productivity in a given area. Several facets of the proposed and alternative actions may alter the existing physical and chemical oceanography of the Prudhoe Bay area. Descriptions in this section, and additional technical details presented in Appendix C provided the basis for the mathematical current modeling of the area (Section 4.2, Physical and Chemical Oceanography, and Appendix D), the evaluation of impacts to the marine resources (Section 4.2, Marine Biology), and analysis of coastal processes (Appendix I). 3-33 CURRENTS/CIRCULATION The existing circulation pattern is important for four primary reasons. It controls the distribution of water quality char.acteri st ics that in turn influence the distribution of biotic communities. The currents directly influence the movement of biota. Circulation determines sediment transport pathways and hence the resulting distribution of sediment types. The existing circulation also will give some means of estimating the natural rate of dilution and mixing of discharge waters (with the ambient seawaters.) Currents are typically determined by some combination of forces, such as winds, tides, density gradations, storm surges, and the Coriol is effect, that act on a body of water. Early studies by Kinney et al. ( 1972), Wiseman et al. ( 1973), and Dygas ( 1975) around and in the western end of Simpson Lagoon, identified the wind as the primary and dominant driving force for nearshore currents in the Beaufort Sea during the summer open-water periods. Winds are 1 argely from the east during the summer (see Section 3.12), resulting in generally westward currents parallel to the coastline. (By convent ion, an easterly current is a current to the east whereas an easterly wind is a wind from the east.) These arid more recent studies by Matthews (1979) and MUilgall et al. (1978, 1979) carrel ated the current velocity with wind speed. On the average, current velocities varied between 2.5 -4.5 percent of the wind speeds. Average winds for summer are out of the east at about 5 m/s (16 ft/s) and result in average westerly currents on the order of 15 -20 cm/s (6 - 8 ft/s). During fall, winter, and spring when the Beaufort Sea is frozen, wind influence on currents is eliminated and the weaker forces of tides, storm surges, and density gradients are left to drive the currents. Few measurements have been made of under-ice currents. But generally they are very weak; frequently near the lower threshold of standard current meters (1 cm/s, 0.4 in/s). Specific measurements of currents in the immediate vicinity of the proposed project have been made by Matthews (1978), Niedoroda et al. (1979), and Mangarella et al. (1979). During summer open-water periods, they show currents (under typical east wind conditions) north and east of DH 3 to be westerly at 11-13 cm/s (4-5 in/s). Waters immediately east of the existing causeway are presumably diverted north towards the end of the causeway. As the current moves westward past DH 3 it diverges; with the water closest to the dockhead being drawn southward between DH 3 and Stump Island while the water farther north off the end of DH 3 continues westward towards Stump Island. The average southward flowing current midway between DH 3 and Stump Island was 6 cm/s (2 in/s) in 1977, peaking at 18 cm/s (7 in/s). Slightly to the west, just off the eastern tip of Stump Island, the current measured 9.5 cm/s (4 in/s) in 1978. This southward flowing water turns westward south of Stump Island and enters the easternmost port ion of Simpson Lagoon south of Stump Island. This circulation pattern is presumably reversed when winds are reversed, although data to show this are incomplete. Peak current velocities in 5.5 m (18ft) of water about 1.5 km (0.9 mi) north 3-34 of DH 3 have been estimated to be over 80 cm/s (2.6 ft/s) by hindcasting techniques (Heideman 1979). This seems reasonable as 5-day averages have been recorded as high as 57 cm/s (1.8 ft/s) in Harrison Bay (Mungall et al. 1978), and peaks of 60 cm/s (1.9 ft/s) recorded in Simpson Lagoon (Mungall et al. 1979). Under-ice currents have been measured at several locations from immedi- ately north to 3 km (2 mi) north of DH 3 in the proposed project area (Mangarella et al. 1979). Currents were weak and variable with speeds always less than 5 cm/s (1.9 in/s) and frequently near the threshold of instrument sensitivity. No general circulation pattern is apparent under ice; however, as the winter progresses and ice thickness increases to its maximum of about 2 m (6.5 ft), many shallow areas are cut off from circulation because of ice frozen to the bottom. WAVE CLIMATE Waves interact with both fhe seabed and shoreline. Interaction with the seabed in shallow waters can cause a significant amount of sediment resuspensi on as 1 arge waves enter shallow waters or pass over shoa 1 s. Resuspended sediments from wave action are thought by some researchers to be the major source of suspended sediments in nearshore waters of the Beaufort Sea (Naidu 1979). Waves interacting with the shorelines are an important factor affecting coastline and causeway erosion and barrier island migration. The wave regime in the Beaufort Sea is heavily controlled by the location of the permanent ice pack. Since the fetch over which wind stress can effectively generate waves is the distance of open (or semi-open) water between the front of the pack ice and the shoreline, the potential for wave growth ·varies widely from year to year1. Brower and Searby (1977) showed the maximum distance from pack ice to coastline at Point Barrow has been as great as 390 km (242 m) in 1954 and 1958, whereas in 1970 and 1975 it was zero. The same variability is generally true near Prudhoe Bay. However, there is no historic record that substantial open water has developed each summer inside the outer barrier islands. In the immediate vicinity of the proposed project, waves are further controlled by the presence of barrier islands and shallow nearshore waters that act to attenuate waves by refraction, shoaling, and direct blockage, depending on the wind and wave direction. Few direct measure- ments of wave heights have been made. Under typical easterly wind conditions (see Section 3.12) waves will be limited by fetch to periods of 2 - 3 s and heights less than 50 em (20 in). Under severe storm conditions, waves are thought to be limited by the water depth (Heideman 1979). In the storm of September 1979, McCollum (1979) and Barnes (1979) observed waves at DH 3 greater than 1 m (3 ft) high with periods of 7 - 8 s. !The amount of ice coverage that can seriously dampen wave growth is not well known. -- 3-35 Although this wave regime appears benign relative to other coastal areas of the world, it is important to understand that, in the arctic environment, wave action is a key factor in determining the shoreline and barrier island evolution and integrity as discussed in Section 3.4~ Further, it is important to realize that wave energy is proportional to the square of wave height, and hence the occasional severe storms may be more significant in determining long-term geomorphological changes than the average meteorological conditions. STORM SURGES AND TIDES Storm surges and tides are both changes in sea level; the former being changes resulting from the combined effects of wind stress, atmospheric pressure variations and Coriol is force, while the 1 atter result from astronomical forces. Together, surges and tides are significant for several reasons. During the ice-covered winter months, they are thought to be the primary driving force behind the weak under-ice currents. In summer, they may cause significant changes in the depth of shallower water and result in significant wave regime changes. Also, as the water level changes, the elevation at which waves strike shorelines will move up and down, changing the potential for coastline erosion and barrier island migration. Tides in Prudhoe Bay have been measured every summer since 1976 by NOAA. Tidal changes in sea level are generally 20 em (8 in) or less (Chin et al. 1979a), and not particularly significant in oceanographic processes. Surges are extremely variable. Positive and negative surges during open-water periods are related in part to strong westerly and easterly winds, respectively. (A positive surge increases sea level.) Surges also occur in winter when the sea is ice-covered. The cause of these surges is less well understood as they have been known to occur in the absence of major meteorological events. Storm surge activity in the Beaufort Sea has been documented by Reimnitz and Maurer (1978). The biggest storm surge known to have occurred at Prudhoe Bay resulted from a storm in the fall of 1970 when gale force westerly winds created a rise in sea level of about 3 m (10 ft). Extensive coastal areas were flooded and some damage was incurred at the East Dock, where moored barges were lifted and deposited on top of the dock. It is believed this was the highest surge in the past 100 -200 years although comparable magnitude storms occur at about 25-year intervals. The biggest surge in winter, recorded by Matthews in 1973 (Reimnitz and Maurer 1978), was an increase in sea level of about 1.5 m (5 ft). The frequency of such winter surges is not known as little winter data has been taken. Negative surges also occur at all times of the year, and can have important effects, especially in 1 ate winter and early spring when 3-36 little water remains beneath the nearshore ice. Observations in Mackenzie Bay by Henry ( 1975) indicate that negative surges are most common in December and January and that their magnitudes are typically 1 m (3.3 ft) or less. Data taken by Matthews from 01 iktok Point recorded a peak negative surge of 89 em (2.9 ft) during one winter's observations (Aagaard 1978). COASTAL EROSION AND BARRIER ISLAND MIGRATION Coastal erosion and barrier island migration result from wave action and thermal and chemical degradation of permafrost. An understanding of present erosion and migration patterns as they relate to the existing wave climate is necessary to allow assessment of the future integrity of the islands and the potential for erosion of the proposed causeway extension. Erosion and migration patterns generally r~flect the dominance of wind and waves from the east. Most barrier islands are elongating, predominantly through spit formation to the west, at estimated rates varying between 6 m/yr (20 ft/yr) (Wiseman et al. 1973) and 2 m/yr (7 ft/yr) (Naidu 1978). Net littoral drift rates, also to the west, have been estimated on the Beaufort coast by Hume and Schalk (1967), Kinney et al. (1972), Dygas and Burrell (1975), and Grider et al. (1978). The latter estimated values of 1000 m3/yr (1308 yd3/yr) at the base of the West Dock, qne-third of which may be due to degradation of the dock itself, effectively reducing the westward drift to about 670 m3/yr (876 yd3/yr). Much of the material for 1 ittoral drift and spit formation comes from erosion of the coast and barrier islands. Erosion rates for some of the barrier islands of the Return and Jones Islands group have been estimated at 1.4 -2.0 m/yr (4.5 -6.5 ft/yr) by Cannon and Rawlinson (1978). Rates along the mainland, south of Simpson Lagoon, have been estimated at 1.0 -4.5 m/yr (3 -15 ft/yr) by Burrell et al. (1975). Rates vary from point to point depending on the local morphology, the orientation, the exposure of the coast and, according to Lewellen (1977), on the ice content of the coastal sediments and size of sediments being eroded. Stump Island migration was examined with air photos from 1950 and 1970 by Barnes et al. (1977) (Figure 3.8-1). Its behavior is somewhat unique among the arctic barrier islands that have been studied. Both ends of the island have moved to the northeast offshore (the southeast end by 275 m, 902 ft), while the main body of the island has moved toward shore by 75-200m (246-656ft), thus straightening the island from its previous arcuate shape. Also the island has increased in area by 120,000 m2 (1.3 million ft2). It has been suggested that the barrier islands' long-term shoreward migration rate may be approximately equal to the mainland coastal erosion rate such that the distance between the mainland and barrier islands is maintained. See Section 3.4 for a more complete discussion of the origin and evolution of the barrier islands. 3-37 a. Bathymetric contours at 0.3m (1-f't) intervals and landforms from the 1'95'0 survey. U.S. Coast and Geodetic Survey smooth sheet 7857. STUMP ISLAND BATHYMETRY IN FEET 1976 146" 10' b. Bathymetric contours at 0.3m (1·-·tt} i'ntervals from the 1976 U.S. Geological Survey, KARLUK data. Landforms from June 26, 1970 aereal photograophy for U.S.G.S. orthophotomap of Beechey Point B-4 NW. The inner causeway segment was constructed in spring 1975 a:nd the outer se§ment in the winter of 1975-1976· .. STUMP ISLAND MIGRATION AND BATHYMETRY CHANGES PBU Waterflood Environmental Impact Statement 3-38 Source: Barnes et al. 1977 Figure 3.8-1 Recent erosional changes to the existing PBU causeway and a man-made artificial island, Niakuk III, were documented by Barnes and Ross (1980). A storm with strong winds from the northeast occurred in September and October 1979 and lasted 9 days. Figure 3.8-2 illustrates some of the changes that took place before the storm in the summer months and during the storm in the fall. SEDIMENTS AND SEDIMENT TRANSPORT PATHWAYS Suspended sediments are initially derived from freshwater river inflow, coastal erosion, and less often, seabed erosion. After initial trans- port and deposition, sediments are frequently resuspended in shallow waters due to wave and current action and, to a lesser degree, in deeper waters by ice gouge and current action. Dominant longshore currents contain most suspended and resuspended sediments within the shallow nearshore zone. Dredging activities and placement of causeway fill associated with the proposed project will disturb a limited acreage of bottom sediments and changes in circulation from the proposed project may indirectly alter existing regional patterns of sedimentation. According to Feder et al. (1976), the Sagavanirktok River is the pre- dominant source of the fine grained sediments found around the causeway. Bottom sediments in this area are composed mostly (>85 percent) of fine silt, silt, very fine sand, and fine sand, with fine sands dominating waters less than 1.8 m (6 ft) deep and silts dominating waters deeper than 1.8 m (Chin et al. 1979b). The general trend is one of increasing amounts of fine material with depth. Organic carbon averages about 0.85 percent of the dry sediment weight. Variability is high, and no particular pattern in organic carbon distri- bution was noted near DH 3 (Spight 1979). Concentrations of trace metals are low and chlorinated hydrocarbon pesticides and PCB' s are essentially absent in the sediments along the proposed extended causeway (Peterson 1980). WATER QUALITY The existing water quality discussed here may be impacted directly by discharge waters and indirectly by changes in circulation resulting from the proposed causeway extension. A 1 so, some short-term impacts may occur during placement of causeway fill and dredging for outfall pipe- lines. Water quality is a primary agent in determining biological use of the area, and it is likely that the distribution of water quality characteristics may be reflected in the biota distribution. The water quality characteristics discussed include dissolved oxygen, pH, temper- ature, salinity, total suspended solids, water clarity, and nutrients. A detailed description is provided in Appendix C. 3-39 NIAKUK Ill JULY 1979 10 SEPT 1979 NOV 1979 NOT TO SCALE Sketched from aerial photos, shipboard photos, and notebook sketches. Source: Barnes and Ross 1980 WEST DOCK 16m (52 ft) MID SUMMER 1979 29 SEPT 1979 UNDERCUT BEACH VERTICAL BLUFF (IN FROZEN MATERIAL?) 12m (39 tt) ~ NOV 1979 FROZEN BOTTOM AT 50-cm (20-in) DEPTH 14m (46 ft) FROM ROAD) EROSION 16 m (52 tt) DIAGRAMATIC REPRESENTATION OF THE SEQUENTIAL EROSION OF THE HEAD OF WEST DOCK & THE ARTIFICIAL ISLAND NIAKUK 3 PBU Waterflood Environmental Impact Statement Figure 3.8-2 3-40 Dissolved oxygen (DO) concentrations in the nearshore zone are usually high (Hufford 1974, FERC 1979, Chin et al. 1979a), and the temporal and spatial variations that have been observed are not considered significant in restricting biota. DO concentrations around the existing causeway and northwards out to about 6 m (20 ft) range from 8.2 -14.0 mg/1 (Chin et al. 1979a). Within that range, values ran slightly higher for bottom water than surface water and winter under-ice values ran about in the middle. Elsewhere, Alexander et al. (1974) found mean DO concentrations of 7.73 mg/1 in Simpson Lagoon during August 1970. Water temperatures vary widely both in space and time during open water due to wind-generated currents and the influence of ~iver runoff (Doxey 1977). Water temperature variations under ice are generally much less. The total variation in temperature during open water is from 0° -12oC (53°F) (Alexander et al. 1974) with the warmest temperatures occurring in the shallow nearshore areas, while the under-ice range is generally -1.5° to -3.4°C (29° -26°F) (Woodward-Clyde 1979), excepting the occasional high salinity pockets of water trapped under ice where temperatures can drop to -12oC (10°F) (Schell 1974). Generally, waters less than about 2m (7 ft) deep are well mixed in the vicinity of the proposed project, while deeper waters are stratified with the bottom water 3° -8° C co 1 der than the surface water (Chin 1980). The mixing is due primarily to wind and waves; hence, stronger winds cause the boundary between mixed and stratified waters to move offshore. Strong winds from the east cause a zone of partial upwelling on the west side of the existing causeway, which draws deeper, colder water from north of the causeway southward past the west side Qf DH 3. Therefore, waters west of the causeway are, on the average, colder than on the east (Mungall et al. 1978, Spight 1979). The average difference is 1.6°C (Doxey 1977), and the maximum during 1976 open water was 5.5°C (Doxey 1977). It should be added that the greatest water temperature variation to occur in 24 hours was 6°C (Doxey 1977). The relatively cold water on the west side of the dock continues westward into the eastern port ion of Simps on Lagoon unt i 1 it eventually becomes diluted. Under less frequent westerly winds this pattern breaks down and the flow pattern is partially reversed. Salinity varies widely during summer due to wind-driven currents, freshwater runoff, and melting sea ice, ranging from near zero to typical open-ocean seawater values of 32 ppt. During winter under-ice conditions, salinities are more stable with values near 32 ppt except in pockets where the water is trapped by ice freezing to the bottom or where brine drainage from freezing ice is trapped in depressions in the bottom. Figures 3.8-3 and 3.8-4 show typical d istri but ions during summer. As with temperatures, salinities are vertically homogenous in shallow waters and grow more stratified in deeper waters north of the West Dock. The circulation patterns caused by the existing causeway are clearly evident from lower salinities at 1m extending north along the east side of the causeway and from the higher salinity bottom water that is drawn south to DH 3 and slightly past it on the west. Surface 3-41 w I .,f::> N :E I» -(I) .., -0 0 c. m ;::, < -· .., 0 ;::, 3 (I) ;::, -I» 3 '0 I» (') -en -I» -(I) 3 (I) ;::, - "T1 tE' c: .., (I) (A) ()) I (A) ~25~ 70°2 s' <~.'' SALINITY (ppt) DISTRIBUTION AT 1m (3.2 ft) ON AUGUST 13, 1978 -70°20' 0 .. 0 OJ " • Station --lsohaline 0 I 2 3 Kilometers 0 z 4 6 8 10 12 14 16 18,000 Fee 1 Source: Chin et al. 1979a • -:-"::.·.~·-···· ·~ • / 22 • 0 N I I I I I I I I I I I I I I I I I I I I \ I I I ' I I ; I I I I / ;'"' ~ '1'-"i i '\. I \ I() I \ N I \ I I I ; I 1 I I \ { \ ' ~ \ /" I ,' ~ \ )~_ ... I \ // ~\:\ \, N ' I \ I I ' ' ' \ I ' ~ I 0 I 1'1 -;--I() I N I I I I " / I I I I I " / _I --- "' N . 0 ... / / / / \ ' I I I ' ' I \ I \ \ I I I \ I I I I I "' ' I " I / I I I I I I I I I I I I I 0 >-J: a. <( a: (!)(X) o ..... 0.0) 0 ,... 1-a ocs~ C/)1-!:!:!(/) t-:::::> -(.!) ~:::::> ..J<( <( CI)Z ~0 0 1- 1- 0 al -======l-z / .... ___ .., ,--""' 0 "' f! ~ ! 0 .. ·E ., .!! .. >< c:: (\j " .&! 0 .. 0 -0 N 0 0 ,... ,,. .. 0 0 q !!! !!! :!: £:! 2 GO ID· <t (\j 0 -- Gi .. lL , I I .... · ,0£ oa ... - Ill en ..... en ,... Ill .. Gl ·= .r:. .. 0 .. -= a; .1:. 0 ... ;;:,. :I "' 0 0 C/) PBU Waterflood Environmental Impact Statement Figure 3.8-4 3-43 salinities show this saline water upwelling on the west side of the existing causeway and moving westward, influencing the water in the eastern portion of Simpson Lagoon. Total suspended sol ids (TSS) in the nearshore zone are derived from river runoff, coastal erosion, and resuspension of bottom sediments. During summer, TSS concentrations are commonly greater than 50 mg/1 in shallow water. Farther offshore TSS levels are usually about 5 mg/1, except· during sustained wind events that break up the stratified 1 ayer and resuspend bottom sediments. Deep water often displays clear marine water underlying turbid fresh or brackish water. During winter, TSS concentrations are low in shallow and deep water, often being between 2 and 10 mg/1. Water clarity is measured either as transmissivity or turbidity. Within the project area, transmissivity will be low in summer (0 -36 percent) and turbidity high. During winter, transmissivity will be high (60 -82 percent) and turbidity low with water clarity uniform through- out the water column (Mangarella et al. 1979). As with temperature and salinity, water clarity shows the same pattern of being well-mixed in waters less than 2 m (7 ft) deep under open-water conditions, and stratified in deeper waters where clearer water underlies more turbid water. This situation arises because relatively fresh water rides on top of saline marine water. Little is known about the distribution of nutrients in the project area. Work by Schell (1974) in Simpson Lagoon shows that inorganic nitrogen present at the start of the summer is rapidly depleted through biological utilization, thus limiting the phytoplankton productivity, while phosphates appear to be well in excess of limiting concentrations. An exception to this is found in fresh water in rivers and delta areas where productivity is primarily phosphate limited. It is thus probable that variations in the distribution of nitrogenous nutrients will play an important role in the biota distribution. ICE Ice is a significant constraining factor on any structure (causeway) that may extend from shore into Beaufort Sea waters and on any structure (gravel island) erected on the shallow shelf sediments in the Prudhoe Bay area. Ice is found in offshore areas incorporating subsea permafrost. It may be inherent in gravel fi 11 taken from the seabed and then exposed to subfreezing air temperatures (notwithstanding physical compaction), on superstructures (structural icing), and in zones of bottom and floating 1 andfast sea ice. The dominant ice form to be addressed herein is sea ice, specifically sea ice in the landfast zones. 3-44 ; There are two landfast ice zones (also called shorefast ice). They are the bottom fast-ice zone (the inner belt) and the floating fast-ice zone (the outer belt). They develop along the coast of the Beaufort Sea and may extend from the beach to approximately the 20-m (65-ft) isobath. Conditions within the zones can change dramatically depending upon ocean, wind, current, and polar pack ice forces to which the landfast ice is subjected during formation and northward extension, and in late spring breakup. These forces can alter the ice canopy by rotating, shearing, ridging and hummocking, and transporting segments of the canopy. To the north of the zones of landfast ice formation are the transition ice zones (shear zone and seasonal pack ice zone) and the polar pack ice zone. North of Prudhoe Bay the transition zone is typically located some 18 -22 km (11 -14 mi) offshore. During the open-water period, floating or grounded multi-year floes and pressure ridge remnants are present in the waters between the coast and the polar pack. Grounded bergy bits, freshwater ice floes from nearby river deltas, and glacier ice island remnants may also be found even in water inside the 2-m (6.6-ft) isobath. During fall or spring storms, these ice types can become potentially destructive particularly when accompanied by a storm surge. The inner belt of nearshore fast ice begins to develop during 1 ate September and early October and will grow to about 2m (6.6 ft) thick by 1 ate March. Ice forms first along the coast due to shallow water, low salinity, and the generally more quiescent surface conditions (Wadhams 1979). If waters are calm, ice will form rapidly, and thicken, strengthen and harden into a smooth sheet. It will rest on the shallow sea bottom and normally gives the appearance of a level sheet with occasional small hummock areas and tidal cracks. It is nearly static throughout the winter, and it can 1 ast unt i1 mid-July. Late fa 11 and early winter storms, however, can drastically alter the surface morphol- ogy of the inner and outer belts of landfast ice. Specific information is scarce on ice movement and deformation events in the Prudhoe Bay region, particularly for early winter when the combination of limited daylight, cold weather, and thin ice restrict field studies (Kovacs 1978). The outer fast-ice belt (floating fast ice) is topographically char- acterized by fields of low ridges and hummocks. During freeze-up, areas of rafted rubble or hummocky ice are generated by fall storms and pressures created by seasonal and polar pack ice pushing southward against young, first-year fast ice. These pressures probably result from an onshore wind pattern caused by a gradual fall/winter steepening of regional surface barometric gradients. Beaufort Sea ice conditions are extremely variable from year to year. When the fast ice is thin and the force of the pack ice is of short duration and limited intensity, only the outer limits of the fast ice -- 3-45 will buckle and form small ridges with shallow keels. If, however, pressures from the pack ice are high and of long duration, 1 arge pres- sure ridges of broken blocks wi 11 form and may have keels that wi 11 extend to and anchor at the sea floor. As temperatures drop, the 1 andfast ice wi 11 continue to thicken and strengthen and become more resistant to pressures from the polar pack and lateral deformation. It will become a more stable platform protected by a relatively narrow zone of stamukhi ice (grounded ridges). In 1 ate May or early June when river breakup starts and fresh water spreads out over the sea ice, the shorefast ice that is frozen to the sea floor along the coast out to about the 2-m (6.5-ft) isobath, thins and lifts from the bottom. The ice continues to thin and weaken until about mid-July when it breaks up and the open-water season begins. Dates of shorefast ice breakup and the sequence by area are often predictable to within a few days (Bilello 1979). Table 3.8-1 presents a summary of the annual ice cycle. During the open-water season, remnant seasona 1 ice and the po 1 ar pack ice, aided by predominantly easterly winds, retreat northward 32 -80 km (20-50 mi) offshore (Figure 3.8-5). The distance from shore varies widely from year to year, and there are times when strong westerly or northerly winds may drive the polar ice pack shoreward. If the winds are severe enough and their duration long enough, ride-up, pile-up and override may occur along the Beaufort Sea coast. Ice ride-up, pile-up and override occur most often in the fall or spring along the Beaufort Sea coast. Yet winter ice movement can be dynamic even in areas protected by barrier islands (Brower 1960; Appendix J). Steep shores, whether they be natural coastal bluffs, a constructed berm, causeway, or gravel island are not immune to extensive damage by sea ice forces (Appendix J). At depths of less than 6 m (20ft), bottom gouging by ice fragments may be very frequent, although the micro-relief of gouges is generally less than 60 em (2ft) (Kovacs 1972). Frazil ice, including anchor ice and underwater ice, has been reported in freshwater lakes, rivers, and streams. However, in 1969 in McMurdo Sound, Antarctica, aggregations of ice were reported to accumulate below annual sea ice and on the seabed (anchor ice) (Dayton et al. 1969). More recently, under-ice divers in the Bering, Chukchi, and Beaufort Seas have reported areas of soft 11 slush 11 ice, characterized by consider- able relief, as well as anchor ice (Reimnitz and Dunton 1969). From knowledge of frazil ice formation in fresh water, most authorities agree that it does not form, per se, under an ice cover. It is agreed that, as in fresh water, seawaterfrazil ice will form in open super- coo 1 ed turbu 1 ent water, or from he at transfer through a broken ice cover. It will also form in polynyas or open leads where surface turbu 1 ence may be weak but where density driven convection p 1 umes can 3-46 TABLE 3.8-1 AVERAGE ANNUAL ICE CYCLE WITHIN THE SHOREFAST ICE AREA, CENTRAL BEAUFORT SEA COAST, ALASKA 1. New ice formation 2. First continuous shorefast ice sheet forms. Ice sheet can be unstable outside bays and the barrier islands and susceptible to deformation. 3. Extension and modification of fast ice. Though few direct field observations cover this period the general sequence involves: o Seaward extension of the ice edge o Minor ridging of successive ice edges o Incursions of multi-year ice o Grounded ice in situ or driven shoreward 4. Stabilization of landfast ice sheet inside the 15m isobath (50ft depth). Atmospheric pressure modifications can alter ice morphology. 5. Stable ice inside about 30m isobath (100ft depth). 6. River flooding of fast ice. 7. Melt pool formation on surface of ice· sheet. 8. Melting and weakening of ice. First openings and movement of decaying ice. 9. Breakup 10. Nearshore area largely free of fast ice. Some deep-draft ol~ ice and ridge fragments may be present. Late Sept./Early Oct. Mid to late October Nov -Jan/Feb November -December · March-April/Early May Late May Early June June-Early July Late June into August July/August/September 3 Oct(a) 25 May(a) 10 June(a) 10 June(a) 30 June(a) 1 August(a) (a) Dates are based on available LANDSAT imagery for 1973-1977. An identifiable event may occur anywhere between the dates of available clear frames which bracket the latest date of recognized non-occurrence and the identified date of its identified occurrence. The average of these dates is used here. (Source: Barry 1977, Barry et al. 1979). 3-47 70 ABSOLUTE MAXIMUM ALASKA SOURCE: MODIFIED FROM AMERICAN GEOGRAPHICAL SOCIETY MAP OF THE ARCTIC REGION, 1975. AVERAGE & ABSOLUTE MAXIMUM RETREAT OF THE EDGE OF PACK ICE ALONG THE BEAUFORT SEA COAST PBU Waterflood Environmental Impact Statement Figure -3.8-5 • 3-48 carry frazil downward into the water column and under the ice canopy. But, unlike freshwater frazil, frazil ice in marine waters also may form under an established ice canopy, the result of cold brine drainage from the cover into the water column. Frazil ice can be active or passive. In the active state it will tend to cling to an obstruction, while in the passive state it is more apt to clog than adhere to a structure or obstruction. Unfortunately, most research into the nature of active/passive ice or the 11 mix 11 of these states of marine frazil in the field is conjectural. Anchor ice (bottom ice) is a form of frazil and, like frazil, will appear only in supercooled water. If ice growth is significant, sufficient buoyancy may be attained to float bottom material to the underside of an ice cover. 3.9 MARINE BIOLOGY Marine biological production in the study area is important locally and regionally in supporting subsistence, limited commercial and sport fisheries, and waterfowl and marine mammal harvests. Feeding and reproduction by migratory anadromous fish and waterfowl in the Prudhoe Bay area contribute to catches elsewhere in the Beaufort Sea and farther south into the Chukchi and Bering Seas. Waterfowl that breed in the Arctic migrate as far south as South America. Use of this area by migratory species is limited primarily to the brief open-water period. The Prudhoe Bay area marine biological environment is dominated by physical features. These features are both static, such as the shallow sloped bathymetry and barrier islands, and dynamic, such as the open- water, ice-cover and transitional periods, seasonal influx of fresh water, and periodic storms. Although the dynamic characteristics of several ecosystem components have not been investigated adequately, observed low species diversities (Feder et al. 1976a,b,c) and severe physical disruptions of pelagic and benthic habitats suggest that the shallow-water marine biological assemblage is physically controlled, as defined by Sanders (1968). This implies that the predominant species have adapted to the harsh physical environment. GENERAL ECOLOGY The marine ecosystem in the vicinity of Prudhoe Bay appears to have a relatively simple structure. Most of the energy reaching resources harvested by man apparently passes through a few abundant forage species. The major structural elements of this ecosystem are organic detritus, bacteria, phytoplankton, ice algae, benthic macroalgae, infaunal benthic invertebrates, epifaunal benthic invertebrates, zoo- plankton, fish, and marine mammals. 3-49 • Rates of energy transfer are extremely seasonal, being much higher in the open-water season than under the ice. Many major components of the nearshore ecosystem make long migrations from the area during the winter season. Although observations under the ice are limited (Tarbox et al. 1979, Mangarella et al. 1979), the predominant transport mechanisms are interrupted by fast ice during the winter. Energy enters the system primarily through the photosynthetic activity of phytoplankton and algae and from the addition of terrigenous organic debris from shoreline ero- sion and river runoff (Schell 1978). The potential for chemosynthetic production by bacteria is not currently known. Energy is exported from the Prudhoe Bay area by migrating anadromous fish, waterfowl, and mam- mals, including man. PRIMARY PRODUCERS The major primary producers in the Prudhoe Bay area are phytoplankton, ice algae, benthic algae, and possibly bacteria. Approximately 22 percent of the total carbon avai 1 able in the area may be derived from these sources, the rest originates from imported terrigenous organic debris (Schell 1978). However, a large majority (greater than 80 percent) of carbon present in higher trophic 1 eve 1 s is from modern marine sources, especially phytoplankton (Schnell 1980). Phytopl ankters common to this region often have circumpolar distribu- tions (Bursa 1963, Horner 1969, Coyle 1974, Horner et al. 1974, Hsiao 1976). The abundance and diversity of phytoplankton exhibit pronounced seasonality in response to varying light, nutrient, and hydrographic conditions. A phytoplankton bloom occurs during the open-water period. Primary production, which ranges from 13 -23 grams carbonfm2fyr (g Cfm2fyr) in the lagoon region, is generally higher in the clearer, saline waters offshore than in the brackish surface or nearshore waters (Horner et al. 1974). Ice algae, consisting largely of pennate diatoms and flagellates, typically bloom in the spring prior to the phytoplankton bloom. Al- though the total production by ice algae is apparently low (Alexander et al. 1974, Horner et al. 1974), the timing of their bloom may be of considerable importance to zoop 1 ankton and benthic invertebrates whose relatively slow response to the annual energy influx is limited by the brevity of the open-water season. Benthic diatoms and macroalgae, such as laminarian kelps, make an unmeasured contribution to the annual primary production of the Prudhoe Bay area. The density of kelp patches is low near shore and generally increases with depth (Beehler et al. 1979). ZOOPLANKTON Beaufort Sea zooplankton consist of holoplanktonic species that occur throughout the arctic basin, are expatriated from the Bering and Chukchi 3-50 Seas, or are characteristic of neritic, less saline environments, and meroplanktonic species (English and Horner 1976). Meroplankton consists of eggs and larvae of fish (ichthyoplankton) and benthic invertebrates, which are planktonic only during these developmental stages; holoplankton are planktonic throughout their life histories. Some primarily benthic species, such as amphipods and mysids, often temporarily .swim into the water column, and thus may behave like zoo- plankters with respect to their vulnerability to entrainment. The nearshore, neritic waters of Prudhoe Bay are dominated by copepods during the open-water season and contained very few meroplankters at the time of sampling (Horner et al. 1974). The lagoon area between Prudhoe Bay and the Midway Islands also is dominated by copepods, although species diversity was higher than that in the nearshore area. Mero- plankton was again a minor component and consisted of barnacle, crab, and polychaete larvae (Horner et al. 1974). Seaward of the Midway Islands the zooplankton is more oceanic in composition. Although still dominated by copepods, meroplankton was a much larger component than in the other areas (Horner et al. 1974). Zooplankton composition at the project site can be expected to fluctuate tempori ly with changes in hydrography. Ichthyoplankton is discussed below under 11 Fish.11 BENTHOS Benthic organisms in the primary impact area play an essential role in the marine food web. This is especially true of motile epibenthic species. Benthic organisms in the area consist primarily of infaunal invertebrates (e.g., polychaetes, clams, and various crustaceans) and epifaunal invertebrates (e.g., amphipods, isopods, and mysids) (Carey and Ruff 1977; Carey 1977, 1978; Feder et al. 1976a,c; Grider 1977, 1978). As is characteristic of arctic benthic invertebrates (Thorson 1950), a 1 arge proportion (58 ~ 68 percent) of the Prudhoe Bay area species reproduce by direct development (e.g., produce demersal eggs or brood their young) rather than with planktonic larvae (Feder et al. 1976a). Benthic assemb 1 ages in this region vary among nearshore areas, inshore areas, and offshore areas. Nearshore areas shallower than 0.5 m (1.6 ft) have very low densities of benthic infauna (Broad 1977, Carey and Ruff 1977, Feder et al. 1976a). Both nearshore and inshore areas (0.5 - 2 m, 1.6 - 7 ft) typically experience fast ice freezing to the substrate. Inshore areas also have low densities of benthic organisms and are characterized by motile, opportunistic epibenthos (e.g., amphipods and isopods) that recolonize the area after the ice melts in the spring (Broad 1977; Broad et al. 1978; Feder et al. 1976a,c; Grider et al. 1977, 1978; Chin et al. 1979a,b). Epibenthic crustaceans are approximately equally abundant in these two areas, but infaunal species are more abundant in inshore areas, reflecting the greater substrate 3-51 stability. Offshore areas (greater than 10m, 33ft) are characterized by a richer benthic fauna than the areas closer to shore (Carey and Ruff 1977). The infauna is dominated by polychaetes and the epifaunal by amphipods (Carey 1978). Depth is apparently the major physical indi- cator of benthic distributions in offshore areas (Carey 1978). Sessile epifaunal species found on limited hard substrates (e.g. boulder patches, kelp fronds) in the Prudhoe Bay area provide a source of potential biofoulers of new hard substrates that may be constructed underwater. These species currently are uncommon in the Prudhoe Bay area (Dunton and Schonberg 1979, Beehler et al. 1979), but they are distributed by planktonic larvae and have high reproductive potentials. FISH Marine and anadromous fish comprise the component of the marine biota of the Prudhoe Bay area most vulnerable to population level impacts from the proposed project including intake operation and causeway extension. They also are highly important to the Inupiat subsistence fishery, limited sport and commercial fisheries, and in area food webs. Because of this importance and the expected sensitivity of fish to the project, a detailed description of known life history and distribution informa- tion for key species is provided in Appendix E. A brief summary of aspects of particular relevance to evaluating project impacts is pre- sented here. Two marine fish species (arctic cod, fourhorn sculpin) and three anadro- mous fish species (arctic char, least cisco, and arctic cisco) dominate the Prudhoe Bay region marine environment in which 21 fish species have been identified (Craig and Haldorson 1979, Moulton et al. 1980). These five species have accounted for over 90 percent of the fish caught in summer sampling in Prudhoe Bay and adjoining Beaufort Sea coastal areas. Arctic cod ( Boreogadus said a) is by far the most numerous marine fish species in the Prudhoe Bay area, especially in waters greater than 2 m (6.5 ft) deep. Large schools of arctic cod have been observed both visually (Tarbox and Spight 1979) and in acoustic surveys (Moulton et al. 1980) during the brief open-water period. There has been a strong suggestion that arctic cod move on and offshore in synchrony with an on and offshore movement of the marine water mass that underlies the less saline surface layer (Moulton et al. 1980). However, dense schools have a 1 so been reported near shore in Simp son Lagoon west of the Kuparuk River (Craig and Haldorson 1979). This species is often reported to concentrate under floating ice, a characteristic that provides some protection from aerial predators. This behavior may also account for a reported association with barges and boats at several dockheads in the area (Tarbox and Spight 1979). Sampling during the 9 months when the area is iced-in is extremely difficult. Limited diver observation, gill • 3-5-2 net sampling, and acoustic sampling under the ice have failed to produce significant catches of arctic cod (Craig and Haldorson 1979, Tarbox and Thorne 1979). Although no local data exist, it is probable that arctic cod move to somewhat deeper waters during the winter and spawn offshore in early to mid-winter (Ross 1968, in Tarbox and Moulton 1980). Larvae 5 - 9 mm long have been captured in May (Andriyashev 1954). Based on the size of young-of-the-year in Prudhoe Bay (up to 15 -24 mm) and growth rates observed (about 0.2 mm/d in August 1979), hatching of eggs to larvae was estimated to have occurred in late spring or early summer, perhaps offshore and east of Prudhoe Bay (Tarbox and Moulton 1980). Details of larval abundance, distribution, and growth are incomplete. None was taken during under-ice plankton pumping between February and May 1979 (Tarbox et al. 1979). Numbers were generally low (<16/1000 m3) in July and early August 1979. A sharp increase in density of cod larvae (to 176/1000 m3) in near-bottom waters occurred in mid-August, possibly following an influx of more marine offshore waters containing greater numbers of larvae (Tarbox and Moulton 1980). Larvae tended to be most dense near the bottom, especially in water greater than 2m (6.5 ft) deep. Because of their size and weak swimming ability, arctic cod larvae and juveniles would be particularly vulnerable to entrainment in the proposed intake. The arctic cod is also an important link in the energy flow in the system, being a primary energy transport link between planktonic organ- isms (e.g. mysids and copepods) (Tarbox and Thorne 1980) upon which they feed, and larger animals (other fish, birds, marine mammals), including man ( BLM 1979). Fourhorn sculpin (Myoxocephalus quadricornis) is a demersal (bottom- oriented) species generally located close to the mainland shore. They have also been observed on the barrier island shorelines in less than 2 m (6.5 ft) of water where they were the most nume~ous fish species in summer 1976 sampling (Bendock 1977). Little is known of their distri- bution in winter, when much of their summer habitat becomes solid with bottomfast ice. Individual fourhorn sculpins have been observed by divers under the ice (Tarbox and Thorne 1980) and they were the most abundant marine species found under the ice at the mouth of the Colville River by Craig and Haldorson (1979). The majority of sculpins caught in Prudhoe Bay are 20 -40 mm long, although individuals as small as 18 mm and as 1 arge as 226 mm have been taken in summer sampling (Moulton et al. 1980). Fourhorn sculpin feed primarily on epibenthic crustaceans (amphipods and isopods) but may also take juvenile fish and copepods (Bendock 1977). In turn they may be eaten by larger fish, especially arctic char, and by seals (BLM 1979). Fourhorn sculpin 1 arval densities ranged from 0 -31/1000 m3 during July through September 1979 studies near and off DH 3 (Tarbox and Moulton 1980). Size ranged from 9.5-17.5 mm but growth rates could not be determined. 3-53 r I r i The bartail snailfish (Liparis herschelinus), another demersal species, is found in close association with attached kelp patches off Prudhoe Bay (Beehler et al. 1979). Snailfish larvae were taken predominantlj in near-bottom samples during July -September 1979 (to 590/1000 m in August) (Tarbox and Moulton 1980). Larvae ranged from 9.5-17.5 mm in length with those greater than 15 mm apparently ready to settle to the bottom as juveniles. Pacific sand 1 ance (Ammodytes hexapterus) and capel in (Mal lotus villosus) are two other manne spec1es that may be important 1n local foodwebs involving birds and other fish. However, they have not been sampled extensively so little is known about their local life history. Capel in (29 -73 mm) were abundant in August 1979 tow net samples off the West Dock and Stump Island (Moulton et al. 1980) and were reported spawning on gravel beaches near Prudhoe Bay in August 1976 (Bendock 1977) . Of the anadromous species found in the Prudhoe Bay area, the arctic char (Salvelinus alpinus) and least and arctic ciscos (Coregonus sardinella and Coregonus autumnalis) are often considered of primary importance. The c1scos may be more numerous. Portions of these anadromous populations (e.g., arctic cisco) (Craig and Griffiths 1978) may overwinter in estuarine river deltas; however, most individuals are thought to overwinter (and spawn) in fresh water. The Sagavanirktok River provides overwintering and spawning habitat for arctic char and broad whitefish (Coregonus nasus) and the Colville River supports populations of arctic cisco, least cisco, broad whitefish, and humpback whitefish (Coregonus pidschian). These anadromous fish generally make longshore m1grat10ns eastward and westward from their parent stream during the brief summer (Figure 3.9-1). There is considerable stock intermingling since some fish from the Prudhoe Bay region rivers move at least as far as the Mackenzie River and, in some cases, westward to Point Barrow (Furniss 1975, in Bendock 1977). Except for those individuals that may overwinter at sea, adults and subadults enter the Beaufort Sea with the spring thaw (June) and return to selected rivers at or before freeze-up (September). These anadromous fish are thus seasonal visitors to the local marine environment. The size of arctic char entering the sea is relatively large (minimum 100 mm fork length) due to the fact that they remain in fresh water for 3 - 4 years before their first migration. Female arctic char migrate in far greater numbers than males. Least cisco of Colville River origin are abundant in Prudhoe Bay (82 -364 mm length) with numbers tending to increase from July through September ( Bendock 1977). Arctic cisco, on the other hand, were less abundant with numbers generally declining following a July peak. Whitefish generally enter the sea much younger and smaller than other anadromous species (20 mm in some cases). Broad whitefish use the Sagavanirktok River in Prudhoe Bay and can reach sizes up to 560 mm (Bendock 1977). The size of the anadromous whitefish species in Prudhoe 3-54 summE-R mOVEmEnT;, of.ARCTIC CHAR luued on fteh laf1f1htg t:lcda: frt.-m lh.e 5aga:vanirlefCJ1t, Cannfn!J_ a:nd F'ir-th. rtver6 --" ---~. \ ________ . ./ . ·-~,~. ., _ __- summER VI5TRISUT!On WZZI A-rcltc Ct .. co ~ Leall Ct1c11 . . . . maji?t" 611urcee "'-the6e 6pec~ are the maeHerrz~ I &lvffle ,.{ve,., I p,.obably 'ome of the river:< lo the wetJt oi lhe Colvflle Fltver. ( -' \ \ / ) / I SOURCE: NOAAIBLM 1978 COASTAL MOVEMENTS OF ANADROMOUS FISH (CONCEPTUALIZED) PBU Waterffood Environmental Impact Statement Figure 3.9-1 3-55 Bay is probably influenced to some extent by the distance an individual has traveled from its natal stream to the bay. Bendock ( 1977) and Doxey ( 1977)• conducted a limited tagging study to determine the effect of the existing PBU causeway on coastal migrations of char, cisco, and whitefish. Their conclusion, based on the location of recoveries of 7 percent of the fish tagged, was that the causeway is not an impassible barrier to the longshore migrations of at least some adults (>200 mm) of several species. However, potential loss in ultimate spawning potential due to predation while passing the deeper water at the end of the dock or to delays caused by the obstruction were not assessed. Also, the influence of the causeway on other fish life stages and the percent of aborted migrations were not assessed. Craig and Haldorson (1979) estimated 1978 runs of catchable (<275 mm) least and arctic cisco to the Colville River at 590,000 and 250,000 fish, respectively, based on recaptures in the commercial fishery of fish tagged in Simpson Lagoon. Some 50,000 ci sea and whitefish are taken annually in a winter fishery in the Colville delta (Alt and Kogl 1973, Craig and Haldorson 1979). Assuming all were anadromous forms, this indicates large populations of these species in coastal waters. These anadromous fish are seasonally important in marine food webs and to man through local subsistence and sport fisheries. MARINE BIRDS Marine birds are discussed in Section 3.6. MARINE MAMMALS The status of the bowhead whale as an endangered species and of other marine mammals as protected, as well as the importance of marine mammals to native subsistence and culture, has warranted a detailed discussion of important species, which is provided in Appendix E. Only a general summary is reported here. Until recently marine mammals have not been surveyed extensively in the Prudhoe Bay area. Most studies have focused on the western Beaufort Sea and northern Chukchi Sea, which can be expected to differ somewhat from the central Beaufort Sea areas around Prudhoe Bay. Sixteen marine mammals have been recorded in the Beaufort Sea (NOAA-BLM 1978), of which the following are probably the major species in the project vicinity: Bowhead whales (endangered) Belukha whales Ringed seals Bearded seals Polar bears (see Section 3.6) 3-56 The endangered gray whale apparently does not often come this far east from its usual range into the northern Chukchi Sea; however, some may seasonally enter the western Beaufort Sea (BLM 1979). The marine distribution and abundances of all these species are drama- tically influenced by ice conditions, which vary by season and year. Bowhead (Figure 3.6-1) and belukha whales are summer visitors to the Beaufort Sea, migrating generally eastward in the spring (April and May) to the Canadian Beaufort and westward again in the fall. These species primarily inhabit open leads in the 11 transition zone 11 in their spring movements, which takes them well offshore from the Prudhoe Bay area (Rietz 1979). However, belukha whales have come into the Sagavanirktok delta area during spring migratrion (Swope 1979). During their fall return migrations, ice conditions permit a closer approach to the shoreline. The closest recorded bowhead observation was one animal inshore from McClure Island east of Prudhoe Bay. A study by the North Slope Borough on the traditional use of Cross Island documents local whaling activity and refers to one case of a bowhead inside Cross Island.· Belukha whales have been sighted just offshore of the barrier islands delineating Simpson Lagoon (Johnson 1979b). Jeffery (1980) reports that Eskimo villagers have observed bowheads in waters as shallow as 3.7 m (12-ft), including areas inside the barrier islands. However, this occurrence is considered rare. The ringed seal is by far the most numerous and important seal present. Depending on ice conditions, this species can occur near the project vicinity throughout much of the iced-over period at densities of about l/km2 (Burns 1980). It is concentrated in the transition zone and the remnant ice zone in the open-water period and close to landfast ice the rest of the year. The ringed seal is a staple in the diet of polar bears and remains important to the native subsistence culture. The Beaufort Sea is considered marginal habitat for the bearded seal, which is not numerous and usually limited to the transition ice zones. 3.10 FRESHWATER RESOURCES The Prudhoe Bay freshwater resource provides important fish habitat and a source for industrial and domestic use. Potential impacts from the project on this resource could result from altered flow rates, saltwater spills, and gravel removal operations. PHYSICAL ASPECTS The Prudhoe Bay are a is dotted with sma 11 to intermediate 1 akes and ponds covering up to 15 percent of the surface (Sellmann et al. 1975). The actual areal coverage of lakes for Prudhoe is 25 -30 percent (Gatto 1980). Most lakes are shallow (less than 2m, 6.5 ft, deep) and freeze to the bottom in winter (Childers et al. 1977). Ice isolates lakes and ponds from outside influences for 9 -10 months of the year with 3-57. freeze-up occurring in mid to 1 ate September and breakup occurring in late June or early July (Brewer 1958, Sater 1969). Water quality parameters in lakes and ponds generally exhibit normal ranges throughout the open-water season (see Appendix F for details on water chemistry). Lakes and ponds within 1.5 km (0.9 mi) of the coast are characterized by increasing levels of salt and higher alkalinity than inland waters, presumably due to the influence of salt spray (Bergman et al. 1977), coastal flooding, and salt-rich sediments (Gatto 1980). Lakes that do not freeze completely in winter often exhibit deteriorating water quality as the winter progresses. Dissolved oxygen levels may decrease to near zero and dissolved solids may become greatly concentrated within the unfrozen portion of the lake (Hobbie 1973). Major streams in the Prudhoe Bay region include the Putul igayuk, Kup- aruk, and Sagavanirktok Rivers. The Putul igayuk, a tundra stream, arises within the Arctic Coastal Plain, whereas the Kuparuk and Sagavanirktok headwater in the Brooks Range. The Putul igayuk River ceases flowing in the winter. The Kuparuk and Sagavanirktok apparently maintain a discontinuous winter flow with the majority of water flowing underground. Substantial quantities of unfrozen water exist during the winter within discrete deep pool areas. Discharge rates and other flow information are presented in Appendix F. River breakup and peak flows generally occur in early June. Flow decreases in September and October, paralleling freezing conditions. · Some natural degradation of water quality can occur within river pools during the winter depending on pool characteristics. Dissolved oxygen concentrations may drop to less than 10 percent saturation and dis- solved solids concentrations may increase to several times the summer level (Schallock 1975). BIOLOGICAL ASPECTS Fish cannot survive in ponds or lakes that freeze completely in winter; consequently, area fish resources are 1 imited. Ninespine sticklebacks are able to survive on a year-round basis in a few of the deeper lakes (Bergman et al. 1977). Some lakes are used by fish during seasonally flooded periods if they are connected to streams (Putul igayuk River and Fawn Creek). Overall productivity of the tundra lakes is low when compared to more temperate areas and is limited primarily to the short season. However, production of invertebrate animal life is relatively high during the short summer (Bergman et al. 1977, Griffiths et al. 1975). The Sagavanirktok and Kuparuk Rivers provide important habitat for a variety of anadromous and resident fish. The species present and relevant migration timing information are presented in Table 3.10-1. (See also Section 3.9 and Appendix E for additional information on anadromous species in the marine environment.) Other rivers and streams • 3-58 TABLE 3.10-1 SELECTED LIFE HISTORY INFORMATION FOR FISH UTILIZING THE SAGAVANIRKTOK AND KUPARUK RIVERS Presence · ··· ··· · · - --------Ouf-migratTo~n--In-riiWration Time Sagavan1rktok Kuparuk Spawning Spawning Overwintering Time-River to Sea Sea to River Movements (Non- Speci$s River River Location Time Location . (Anadromous Species) (Andromous Species) Anadromous Species) Comments I Arctic char * Spring fed Mid-August Spring fed Breakup: mid-June Mature fish: early tributaries to early tributaries -mid July August -September December Immature fish: September Burbot * Main stream Winter Deep poo 1 s in --May move into under the ice main stream lakes or upstream areas in summer then downstream to wintering areas in fall Broad whitefish * * Deep pools Fall Deep pools in Breakup: early Late August in lower l"iver lower river June -mid-July ArctiC cisco * Deep pools Fall Deep poo 1 s in Early summer . Late Summer -Uncommon · in lower river lower river -in Sag Marine areas? River Least cisco * Deep pools Fall Deep poo 1 s in Early Summer Fall -Uncommon in lower river lower river -in Sag w coastal lagoons? River I 01 Humpback 1.0 whitefish * Deep pools in Fall Deep pools, Early Sumer Fall lower river in lower river Round * * Deep poo 1 s or Fall Deep pools, --Variable depend- whitefish other areas 1 akes, or ing on local with year-springs population round flow charactert is tics Grayling * * Upstream Late May to Deep pools in --Move upstream Widely tributaries Mid-June lower river to spawning distributed areas during variable breakup -down-movements stream in mid- summer Ninespine stickleback * * Shallow areas Summer Deep pools --Move to spa11n-May move into with aquatic ing areas in saltwater vegetation spring --to wintering areas in fa 11 Slimy sculpin * * 1 Spring Deep pools --Little informa- tion available Sources: Bendock 1979; Craig and McCart 1976; Wilson et al. 1977; Morrow 1976 .,;i 11 in the vicinity (Putul igayuk River and Fawn Creek) do not round flow and apparently have minimal value to fish. use of the 1 ower reaches of these streams undoubt ly occurs thawed season. have year- Some fish during the Winter is a critical time of year for fishes inhabiting the Sagavanirk- tok and Kuparuk Rivers. Fish become concentrated within 1 imited areas where the depth and flow of water prevents freeze-up (Craig and McCart 1974). WATER AVAILABILTY AND USE Water availability in the natural system on the coastal plain is limited to suprapermafrost water, water in the alluvium of major drainages and in thawed alluvium under abandoned oxbow channels, water in taliks, and in ponds, lakes, and streams. Free water may be crucial to survival of indigenous biota by late winter, and resource managers therefore do not consider free water in natural channels as a potential water source for industrial use. Since 1976, North Slope resource managers have applied a policy of combining upland material extraction sites with development of water reservoirs (Peterson 1979). Table 3.10-2 presents winter water availability in existing reservoirs and deep 1 akes. These sources provide 697 mill ion gal of water for winter use. Additionally, Peterson (1979) reports 313,000 gal/d can be withdrawn from other lakes under Alaska Department of Natura 1 Resources water use permits. These withdrawals occur in the summer and fall. Jones (1977) reports one additional lake having 97 million gal of winter water storage. Snow melt and early summer discharge of the Sagavanirktok, Putuligayuk, and Kuparuk Rivers provide sufficient fresh water to fill lakes and reservoirs in the area. Water use in the Prudhoe Bay region includes personal needs, such as drinking, washing, laundering, food preparation, and industrial needs, such as camp maintenance and drilling. Domestic use has increased from about 35 to 85 gal per capita per day, as treatment techniques, storage facilities and camp facilities have improved. Current total use is approximately 800,000 gal/d. 3.11 GROUNDWATER RESOURCES The groundwater resource in the project area could be impacted by road and pad construction, gravel removal operations, waste disposal, and accidental petroleum or saltwater spills. The North Slope is underlain by continuous permafrost. Permafrost generally extends to a depth of 600 m (2000 ft) in the Prudhoe Bay vicinity (Gatto 1980). Ground water may occur above (suprapermafrost water), within (intrapermafrost water), or beneath (subpermafrost water) the permafrost (Muller 1947). 3-60 w I 0'\ ....... I TABLE 3 .10-2 PRUDHOE BAY DEVELOPMENT AREA WATER AVAILABILITY Water Source Total Volume, Mill ion Gallons Winter Volume, ( ) Million Gallons a Reference Big Lake Kuparuk River Reservoirs Arctic Slope Alaska General Sohio (3 reservoirs) Lake Colleen North Slope Borough Reservoir (NANA) Reservoir Putuligayuk River Reservoir Sohio Webster Reservoir 7 118 128 132 34 4 75 309 95 100( ) 80 b (a)winter volume as reported by cited reference or calculated by subtracting the volume of water displaced by 2m (6 ft) of ice (b)Hayes (1977) reports 85 million gal available under ice References: 1. ESL 1978. 2. Wilson et al. 1977. 3. Palmateer 1979. 4 DNR 1979a. 5. Smith 1979. 6. Jones 1977. 7. DNR 1979b. 8. BLM 1978. 1,2 3 4,5 6 5 7 2,8 -~ :::lll Groundwater aquifers are often found in alluvium along major drainages (Kane and Carlson 1973) and in thawed zones (taliks) beneath deep lakes. Water in these areas is hydraulically connected to the surface water. There is no opportunity for intermixing of fresh suprapermafrost water and the sa 1 ine sub permafrost ground water (where the proposed act ion would inject treated seawater) due to permafrost depth (Williams 1970), and because permafrost tends to form an impermeable barrier that prevents fresh water from percolating downward. The amount of supra- permafrost water varies with the depth of the active 1 ayer, but is frozen from mid-September to June. Groundwater quality is probably highest in alluvium beneath rivers. Shallow ground water in these areas is of the calcium bicarbonate type, usually with less than 250 mg/1 of dissolved solids. Ground water beneath lakes in the coastal plain may contain dissolved organic material (Williams 1970). Groundwater temperatures rarely exceed 1.0° -1.5°C (34° -35°F). Saline ground water, mainly of the sodium chloride type, is common below permafrost on the coastal plain. Water quality characteristics of one 3-m (10-ft) well at Prudhoe Bay are provided in Table 3.11-1. Water quality in this well is high. Since the well was located in the Sagavanirktok River alluvium, the quality characteristics are not representative of ground water in the active 1 ayer. 3.12 METEOROLOGY AND AIR QUALITY The proposed act ion entai 1 s introducing several new sources of atmospheric pollutants to the area. In order to estimate the air quality effects of the proposed project, it is necessary to understand the meteorology/climate of the area. Some meteorological and air quality data have been collected at Prudhoe Bay. In addition, extensive meteorological data have been collected at Barrow and Barter Island where the climate is very similar to that of Prudhoe Bay (AEIDC 1976). In combination, these data provide a meteorology data base applicable to Prudhoe Bay adequate for use as input to air qual1ty dispersion models. METEOROLOGY Table 3.12-1 presents a 30-year climatic summary of Barter Island (U.S. Department of Commerce 1977). These data clearly show the severity of the North Slope climate. Freezing temperatures occur year-round, and below zero (°F) temperatures occur in all but the summer months. Rain and snow amounts are relatively light; the area can be classified as semi-arid. Most precipitation falls as snow. Annual percentage frequencies of surface wind at the Deadhorse airport for 1976 are shown in Figure 3.12-1, together with the same kind of frequencies derived from eight observations per day obtained from 3-62 • TABLE 3.11-1 GROUNDWATER QUALITY AT A PRUDHOE BAY WELL(a) Parameter Value Parameter Value(b) Temperature (°C) 6.0 Bicarbonate 117 pH (pH Units) 7.8 Carbonate 0 Conductivity Total (umhos/cm @ 25°C) 215 Hardness 106 Nitrate-N 0.32 Calcium 33 Silica 1.5 Magnesium 5.8 Sulfate 9.5 Iron 0 Fluoride 0.3 Manganese 0.04 Chloride 0.2 Sodium 0.8 Dissolved Solids 111 Potassi urn 0.2 (a)After Balding 1976. (b)values in mg/1 unless otherwise specified. 3-63 TABLE 3.12-1 CLIMATIC SUMMARY, BARTER ISLAND, ALASKA (a) Januarx_ April Ml October Annual Temperature ( • F) Average daily maximum (b) -8.5 8.2 45.5 21.5 15.8 Average daily maximum (b) -21.9 -8.1 34.5 11.2 4.3 Monthly Mean (b) -15.2 0.1 40.0 16.4 10.1 Highest 39 43 78 46 78 Lowest -54 -38 24 -23 -59 Number day minimum~ 32" 31 30 10 31 313 Number day minimum ~ o· 29 23 0 7 168 Precipitation (inches) Normal (b) 0.55 0.23 1.12 0.81 7.05 Maximum monthly 4.08 1.22 3.01 3.62 4.91 Minimum monthly 0.01 T T 0.12 T 24-hour maximum 2.25 0.44 1.64 1.98 2.25 Maximum monthly snow 35.0 12.2 3.8 32.1 35.8 24-hour maximum snow 14.8 4.4 3.4 16.0 17.0 w Number days precipitation 2_ 0.01" 6 6 8 13 91 I 0'\ Wind (mph) ~ Mean speed 14.7 11.9 10.6 14.6 13.1 Prevailing direction w w ENE E E Fastest mile 81 52 40 58 81 Fastest mile direction 270" 270" 250" 270" 270" Cloud Cover (days) (c) Clear 4 8 2 2 50 Partly cloudy 2 9 10 5 68 Cloudy 8 13 19 24 192 (a) Period of record, 1948-1978 (b) Period of record, 1948-1970 (c) Sun continuously below horizon, November 24 to January 17 Source: U.S. Department of Commerce 1977 BARTER ISLAND 1968-77, CALM 1.2% 1:::::::::::::::::::::::::;:;:;:::1 DEADHORSE AIRPORT 1976, CALM 4. 5 °/o ANNUAL WIND FREQUENCY DISTRIBUTION -- PBU Waterflood Environmental Impact Statement 3-65 SOURCE= DAMES 8 MOORE, 1978 Figure 3. 12-1 Barter Island during the 10-year period, 1968 -1977 (U.S. Department of Commerce 1977). The Barter Island data are shown by solid bars, while the Deadhorse data are indicated by shaded bars. The annual wind speed at Barter Island for this 10-year period was 13.6 mph; calms occurred approximately 1.2 percent of the time. At Deadhorse, the average wind speed in 1976 was 12.8 mph; calm conditions occurred a total of 4.5 percent of the time. The slightly different frequency distributions indicated in Figure 3.12-1 possibly could be attributed to either the difference in the length of the respective data sets or the relative coastal orientations of the two sites. Both data sets indicate two dominant flow regions; easterly flow from May to December and westerly flow from January to April. For the purpose of this study, wind patterns during ice-free periods are of particular concern. Dates of ice appearance in the fall vary greatly from year to year, but breakup dates in late spring or early summer appear to be better confined. The predominant wind flow during this period is east to east-northeasterly but, depending on the location of the arctic front, westerly winds also occur frequently. The relative persistence of these two flow regions derived from climatological data collected during the summer season at Barter Island is presented in Figure 3.12-2. Generally, the data indicates easterly flow is more persistent, often prevalent for a week, while westerly winds generally only persist for 1 - 2 days. The longest duration of the easterly flow pattern in the summer within a 10-year period at Barter Island was 18 days, while 10 days was the longest extent of generally westerly winds. The wind rose for a location at Well Pad A during the period from July 1 to September 30, 1979 (Figure 3.12-3), roughly corresponding to the open-water period, shows a somewhat greater predominance of easterly winds. AIR QUALITY Project area air quality is generally good due to few pollutant sources and good dispersion conditions associated with strong year-round winds. Short-lived periods of light winds and poor dispersion conditions occur only occasionally (Radian Corp. 1979b). There are two recent sources from which existing air quality can be estimated: the Sales Gas Conditioning Facility DEIS and Waterflood Project PSD permit application (FERC 1979, Radian 1979b). The latter source includes 6.5 months of on-site monitoring data, while the former presents 11 Worst case" predictions. Table 3.12-2 is a synthesis of these two sources in which the worst values were taken. In all cases, National Air Quality Standards are attained. 3.13 SOUND Introduction of unnatural sounds into a natural environment can cause a variety of reactions in natural fauna. Sound receptors within the 3-66 11) G) u so~ 40- ~ 30 f-.. .. ::s u u 0 -0 a; 20 r-- .c E ::s z 10- \ \ \ \ ~ ,, \ ---Westerly Flow ----~;:asterly Flow \ \ \ ' ' ' ' ' ............ ....__ ol-____ ~l ______ L_I __ -=:===~~-;-~-~--==--~--~--~·f~·--~--~--~--~--__JJ 0 5 10 15 20 Days Persistent OCCURRENCES OF PREVALENT EASTERLY & WESTERLY WIND FLOW DURING THE SUMMER SEASON AT BARTER ISLAND, ALASKA FROM 1964 TO 1974 PBU Waterflood Environmental Impact Statement Figure 3. 12-2 3-67 T I PRUDHOE BAY, CALM 0.00% WIND ROSE PRUDHOE BAY -DRILL PAD A JULY 1, 1979 TO SEPTEMBER 30, 1979 PBU Waterflood Environmental Impact Statement 3-68 Figure 3. 12-3 TABLE 3.12-2 EXISTING AIR QUALITY, PRUDHOE BAY, ALASKA Pollutant Averaging Time TSP Annual 24-hour Annual 24-hour 3-hour co 8-hour 1-hour Annual 1-hour Existing National Ambient Pollutant Level(a) Air Quality Standard(a) 14 75 88 1 19 28 1106 3340 24 113 260 80 365 1300 40,000 10,000 100 240 (a)Micrograms per cubic meter (ug/m3) 3-69 Prudhoe Bay area that could be sensitive to sound produced by the proposed action include caribou, whales, seals, arctic foxes, polar bears, fishes, and other area wildlife. Wildlife adaptability to sounds associated with recent oil field development is generally unknown. Studies of wildlife reaction to industrial and construction noise are discussed further in Section 4.2. Humans in the vicinity are virtually all engaged in oil industry activities. Therefore, they are not considered sensitive to, or annoyed by, these sound sources (as for example would be 11 normal" residents in the vicinity of a construction site) • Construct ion and operation of the Waterflood Project would introduce sever a 1 new temporary and permanent noise sources to the Prudhoe Bay environment. A sound measurement survey was conducted on February 14 and 15, 1979, to determine existing sound levels in the vicinity of the PBU facilities at Prudhoe Bay (FERC 1979). Measurement locations were selected near major noise-producing equipment such as drilling rigs, compressors and gas turbines at each center (Figure 3.13-1). In addition, measurements at the Prudhoe Bay field perimeter were conducted to determine the background ambient sound level1 at greater distances from equipment noise sources. Background ambient sound 1 evel s and a description of the measurement locations are presented in Table 3.13-1. Appendix G contains definitions of acoustical terminology. Major sound sources in the Prudhoe Bay field during the study were the CCP (locations 2 and 3), central power plant (location 5) and drilling sites (locations 6, 8, and 14). Measurements at the northern field perimeter, adjacent to the Beaufort Sea (location 12) indicated a background equivalent sound level of 32 dB. At measurement sites closer to the fields, but away from major sound producing equipment, the background equivalent sound level increased to 39 -44 dB. 3.14 SOCIOECONOMIC CONDITIONS The human society affected by the proposed action is best viewed in two primary references: the North Slope and the State of Alaska. The once stable, closed society of the Inupiat has undergone significant pressure for change. Both the Inupi at and A 1 askans statewide have reaped the rewards and liabilities associated with oil development. Based on the financial expectations generated by oil development in the 197o•s and the current economic recession statewide, most Alaskans, in common with the Inupiat, seek a compromise that will facilitate economic security and preserve the unique qualitites associated with life in Alaska. lsound level used in this report is the A-weighted sound level unless otherwise noted. 3-70 J I w I I -....! I-' "'tJ m c :E I !/ I» -I ll CD .., -0 0 c. I ~~ ) m ::::s < .., 0 ::::s 3 CD ::::s -I» I rfj) --3 '0 I» (") -(J) -I» -CD 3 CD ::::s - 11 (0 c: .., : l SOURCE: FERC 1379 ...... CN I ~ ~" ~ \ \ PRUDHOE BAY " GAS INJECTION PAD * CENTRAL GAS ~ *4 NOISE MEASUREMENT LOCATIONS ··--·-------~ . ~ Measurement Locat io.n 1 2 3 4 5 6 7 8 9 10 11 12 13 14 TABLE 3.13-1 BACKGROUND AMBIENT SOUND LEVELS IN THE PROJECT VICINITY Equivalent Description Sound Level (Leq)-dB 300m (984 ft) from Flow Station #1 56 Central Compressor Plant -74 15 m (49 ft) from turbine air intake Central Compressor Plant-60 120m (394 ft) from flare operation 0.8 km (0.5 mi) from Central Compressor Plant 100m (328ft) from SOHIO Central Power Plant 600 m (1969 ft) from SOHIO Drilling Site Bridge over Kuparuk River 1.2 km (0.7 mi) from Drilling Site (DS) 7 1.7 km (1 mi) from East Dock 10 km (6 mi) north of Gas Injection Pad 3.1 km (2 mi) north of Gas Injection Pad Ki akuk Island 1.8 km (1 mi) south of East Dock 60 m (197 ft) from Drilling Site #13 57 67 44 39 44 44 35 32 32 33 65 Source: FERC 1979, measured on February 14-15, 1979. Locations are illustrated in Figure 3.13-1; 3-72 NORTH SLOPE SOCIOCULTURAL CHARACTERISTICS Central to discussion of the sociocultural conditions prevalent on the North Slope are subsistence activities and political entities. The following brief description is intended to familiarize the reader with significant elements of these features and provide a base for analysis of the proposed action. Contemporary Inupi at society is pressured by forceful change factors, many related to oil and gas development. A significant agent of change is the local North Slope Borough (NSB) government. The NSB has active capital improvements, education, and social services programs funded largely ~y tax revenues from oil development of Prudhoe Bay. Prior to this fund iing source and organization of the NSB, comparatively little attentiorr;' was given to the social and economic needs of the Inupi at. The formation of the NSB in 1972 and the development of a tax-based funding mechanism, which allowed for the building and operation of locally controlled schools and programs aimed at alleviating housing and utility problems, were paramount in shaping the changing appearance of North Slope communities. Other change forces relate to biological resources. First, there is a growing need to scientifically manage fish and wildlife and institute hunting and fishing practices that are compatible with regional carrying capacities. Secondly, there is the potential for major habitat changes due to future oil and gas development and the resultant effect on subsistence resources. Subsistence use, fluctuating fish and game populations, and the resultant effects of habitat changes are both emotional and controversial issues among industry, the Inupiat, and resource managers. Although signficantly pressured toward cultural change, a relatively stable, traditional culture persists among the Inupiat (Worl 1978) along with continued development of adaptive strategies. Adaptive strategies being employed appear to functionally integrate elements of Western and traditional political and economic organization, as well as socially reflecting the changing environment. A key problem for the Inupiat and for those who interact with them is the non-Inupi at view that Western institutions, English language, and a cash economy reflect a changing or 11 acculturation 11 from being traditional Inupi at to becoming fully 11 Westernized.11 Subsistence Traditional Inupiat culture developed over thousands of years of habitation in circumpolar lands. Subsistence hunting and fishing was the central focus of human activity and the foundation of the Inupi at social system. This activity and accompanying social organization remain functional today. Rather than simply food gathering efforts, subsistence activities provide patterns of cooperation, promote an elaborate structure of sharing and distribution, and determine an individual 1 s status and role within the community. - 3-73 Contemporary subsistence activities in the North Slope region are made up of three basic interrelated aspects: economic, social, and cultural. The following discussion from Worl (1978) describes these aspects: "Presently, the economic aspects of subsistence relate to the appropriation of natural resources, primarily food and clothing. Modern equipment and supplies require money, so contemporary economic subsistence systems in the Arctic are interrelated with the monetary economy. The present economy has been described as "mixed" or "dual." Analytically, the economic systems can be held distinct, but the Inupiat experience demonstrates an inter- relationship of the two economic systems. Interrelationship of the economies has facilitated the survival of the Inupiat culture. Cash income opportunities have remained compatible with the subsistence system. University of Alaska Arctic Environmental Information & Data Center The lnupiat view themselves as being closely lin ked to the land and sea. New technology is often adapted to old traditions. 3-74 The appropriation of resources is achieved through an organized system of social relations. Spencer (1959) suggested that the Eskimo family was the key to understanding the sociology of the Barrow Eskimo. He noted that the Eskimo culture tried to raise individuals as useful members of the family, which was the basic economic unit, by promoting cooperation and a level of equality between members of the group. Hippler (1969) believed that the family explains the cultural persistence of the Eskimo. Burch (1975) characterized Eskimo societies in terms of interrelated domestic and local families that together constituted a social network. He noted that major subsistence efforts by males, even in 1970 in the villages, were carried out either on an individual basis or in terms of kin-based hunting and fishing crews. Burch also describes Barrow, which has had the greatest and most intense contact with white influences, as exhibiting a high degree of organizational continuity. Cultural values are the most elusive element of subsistence; yet if subsistence appears to be threatened, its importance to the culture is most strongly defended. Evaluated solely in monetary terms, it is likely that subsistence would be judged a net loss venture. However, it is the absence of economic rationale among participants that may help to explain their cultural values and emotional attachment to the land and environment. The umealik (whaling captain) may spend as much as $6,500 to support his crew and activites associated with whaling because this, not monetary gain, gives him status in the community. Cultural elements reflect the environment with which a group is interacting. The Inupiat believe that their cultural survival is based on a direct and intimate relationship with their environment." Subsistence resources are important to the Inupiat in a dietary sense. Local fish and wildlife resources appear to be nutritionally superior to western foods for many Eskimo people (Jamison et al. 1978). Nutritionally, there are no substitutes readily avail able that satisfy the needs of the Inupiat. The subsistence resources {birds, mammals, and fish) are markedly higher in nutritional values such as vitamins, polyunsaturated fats, and essential minerals (Jamison, et al. 1978). Those foods from outside sources that are most readily available and affordable are high starch, high sugar, and high carbohydrate foods, which have been shown to have a negative impact upon populations who find themselves partially or wholly dependent upon them. Availability and relative low cost of items such as candy, soda pop, and other "converii ence foods" have had telling impact upon the Inupi at already. Witnesses at North Slope public hearings over the last 2-3 years have testified that the cant inuat ion of subsistence hunting is basic to not only the person•s own health, but to the actual survival of the community. Additionally, there are not sufficient employment opportunities to enable the Inupiat to subsist in a total cash economy (BLM 1979). 3-75 Polftical Development Contemporary social organization began as early as 1936. In the 1960•s attempts were made by the Inupiat to politically organize themselves on a regional basis in response to the Alaska Statehood Act, the native land claims effort, and the State lease of Prudhoe Bay to the major oil companies. In November 1961, village leaders met in Barrow at a conference to discuss their common problems, primarily focusing on land rights. As a result of this conference~ the Arctic Slope Native Associ at ion (ASNA) was formed to resolve the aboriginal land rights of the Inupiat. The primary effect of ASNA, outside of the land claims resolution, was the continued political unification of North Slope groups. Under the terms of the Alaska Native Claims Settlement Act (1971), the Arctic Slope Regional Corporation (ASRC) was incorporated to conduct business for profit. The management of ASRC is vested in a board of directors, and its objectives are congressionally mandated. The Inupiats enroll as shareholders and, represented by an elected board of directors, function as a profit-making entity. Another important entity is the Inupi at Community of the Arctic Slope (!CAS). !CAS is a region-wide Indian Reorganization Act tribal government. It is specifically empowered to exe~cise rights and responsibilities relating to the Inupiat position as native Americans and is the intermediary between the individual and community and the Federal government as regards Federal trust responsibilities to native Americans. I CAS is a region a 1 authority with representatives on its board from every North Slope community. It operates through grant and contracts from the Department of Interior, Bureau of Indian Affairs. Its programs include realty, areas of tribal operations, educational grants and scholarships, social services, and a tribal employment rights office. Through resolution from !CAS, the NSB Health and Social Services Agency contracts with the Indian Health Service for the provision of certain services. As a tribal entity, !CAS constituents are all Inupiat now living on the North Slope, unlike the ASRC whose constituents consist of only those Inupiat who enrolled under the provisions of Alaska Native Claims Settlement Act, and who were born prior to December 21, 1972, or those born after that date who have inherited shares from a deceased relative. The North Slope Borough (NSB) was created in 1972 to protect the arctic subsistence economy through environmental planning and zoning regulations and to provide local services and education supported by oil tax revenue. Although the NSB performs the usual functions of a borough government, it has demonstrated a commitment to maintaining traditional values. Its legislative membership is primarily Inupiat and the employment demands are predominantly met with Inupiat personnel (Worl 1978). 3-76 POPULATION AND EMPLOYMENT North Slope There are two major groups currently on the North Slope and each has a distinctive pattern of living and working. First, there are the permanent settlements of Barrow, Anaktuvuk Pass, Atkasook, Kaktovik, Nuiqsut, Point Hope, Point Lay, and Wainwright that are occupied predominately by Eskimos. Second, there are the non-Eskimo transient workers who 1 ive and work on the North Slope for varying periods but make their permanent homes ~1 sewhere. These are the employees of the Prudhoe Bay industrial enct,ave and pipeline camps, employees of the Federal and State government;; who 1 ive in compounds near Eskimo villages or in iso,lated stations, i~nd drilling crews exploring for oil in National Petroleum Reserve ~~Alaska or on State leases issued prior to 1969. The demographic compo~ition of the two groups is quite different; while the local communities iare composed of men, women, and children of all ages, the transient workforce is almost exclusively non-native males between the age of 25 and 65 years. Table 3.14-1 shows the population of these groups in July, 1978. At that time the population of Eskimo communities was roughly equal to the population of the non-resident workforce. Among the latter group, the Prudhoe Bay complex contributed about 91 percent of that total. With the development of the ASRC and the NSB, and the building of new housing in all communities, the admixture of non-Inupiat into ~he communities has increased. Sources of this influx are the NSB, ASRC, the schools, and construct ion and maintenance associated with borough projects.,: While non-Inupiat in-migration even to the small communities has increased, it will be relatively short term, generally lasting .for the duration of a particular project such as school and housing construction or other similar projects. With the building of larger school facilities, more teachers are hired. These teachers, coupled with the NSB Public Safety Officers, constitute the only significant long-term non-Inupi at residents in the small communities. Barrow, on the other: hand, has a rather heavy influx of non-Inupiat, swelling the population of the community to nearly 3,000. High wages, relative ease of finding employment, and increased housing availability have served to make this influx relatively permanent in nature. Table 3.14-2 shows the NSB population by geographical census divisions between 1.960 and 1978. Barrow, the region's communi cat ion, admini s- trat ive, and transport at ion center, grew 60 percent between 1960 and 1970, but between 1970 and 1978 had grown only 29 percent. Between 1970 and 1976, the Prudhoe Bay area grew from zero to almost 9,000; by 1978 the population had declined to 3,619. Prior to the early 1970s, there was 1 ittle immigration of the Eskimo population into smaller villages. Most population movements were from the villages to Barrow and other larger communities, based primarily on 3-77 TABLE 3.14-1 POPULATION OF NORTH SLOPE BOROUGH, JULY 1978 Predominantly Eskimo Communities 4061 Barrow (2471) Anaktuvuk Pass (173) Atkasook (93) Kaktovik (192) Nuiqsut (182) Point Hope (464) Point Lay (57) Wainwright (429) Prudhoe Bay and Pipeline Camps 3367 Prudhoe Bay/Oeadhorse (3052) Pipeline Pump Stations & Camps (315) Federal Government 444 NARL (228) DEW Line (124) Cape Lisburne (92) Exploration Camps and Miscellaneous 229 ASRC Sites Eagle Creek (75) Akulik (29) Tiglikpuk (40) NPR-A Sites Lonely (65) Inigok (60) Tunalik ( 7) Betty Lake (18) Umiat (4) Misc. (1) Miscellaneous 16 TOTAL 8187 Source: North Slope Borough (1979) 3-78 TABLE 3.14-2 I CENSUS DIVISION POPULATION -NORTH SLOPE BOROUGH July Jan. July Jan. July Jan. July Jan. Jan. Census Census (Commun1ty) 1978 1978 1977 1977 1976 1976 1975 1975 1974 1970 1960 BARROW Barrow 2715 (a) 2414(b) 2389 2389 2218 2141 2163 2163 2104 1314 Wainwright 429 (a) 398 394 357 344 341 354 354 315 253 Anaktuvuk Pass 173 152 151 150 150 129 129 134 134 99 35 Cape Lisburne 92 92 92 112 112 112 112 112 112 83 N.A. Atkasook 93 (a) Nuiqsut 182 (a) 157 152 152 149 149 145 145 Point Lay 57 (a) 54 51 51 48 48 27 27 Census Division Remainder 16 16 16 91 91 62 N.A. NPR-A 155 33 33 505 55 UPPER YUKON Kaktovik 192 134 134 123 123 119 119 141 141 123 N.A. Prudhoe Bay/Deadhorse(c) 3619 5318 5318 7765 8801 5531 5022 3158 927 279 KOBUK w I Point Hope 464 412 412 408 408 403 384 404 404 386 324 '-I \!) TOTALS 8Tii7 9ill 9!63 12,065 12,614 9053 8445 6729 4498 Jill N.A. -Not Ava i 1 ab 1 e NPR-A -National Petroleum Reserve -Alaska (a) -Combined Barrow, Atkasook, Nuiqsut, Wainwryght< Pt. Lay= 2922 plus 108 Dew Line. (b) -Includes Dew Line-108. (c) -As Deadhorse and Prudhoe Bay are settlements resulting from oil exploration and discovery activities that commenced subsequent to the 1960 Census, there were, for all practical purposes, no people residing in these areas prior to that time. Source: North Slope Borough (1979). "··::;_, ... ,-;,,i:~ill:\'(i4..,:;~ W &mJlM.-I,....,ZAM~mo•U"i, .. ;;m:_un::;;;::;;wQiiil~~~'""""""'"'"''""'""""""-"'""""'""-------------------------------------------..,;;---.... ------OiiOil:----~~~~~111111!1111!!1!··· employment opportunities· and centralized educational facilities. The formation of the NSB, passage of the Native Claims Settlement Act, and establishment of local schools have encouraged some residents to remain in the villages and have stimulated new or reestablished settlements such as Nuiqsut, Point Lay, and Atkasook. The resettlement of these villages also represents a return to areas that have held subsistence economic importance to the Inupiat. Though there is construction associated with these resettled communities and cash work that provides occasional high wages, the vast majority of food consumption tends to be s~bsistence items for the permanent population. Employment patterns among the two major groups of North Slope inhab- Hants are quite different. In Eskimo towns and villages, employment oijportunities are limited and tend to be seasonal. It is significant to ppint out that the major economic impact through Inupi at employment r~sults from the efforts of the NSB and ASRC and other native entities, niit directly through industry. Village corporations have begun making investments that may prove a viable road to Inupiat employment and training in industry-related areas. Examples of this are the newly formed Pingo Corporation, a consortium of Kaktovik, Wainwright, and Nuiqsut Village Corporations designed to perform construction and service work related to petroleum exploration and production. Similarly, Nuiqsut and Kaktovik Corporations have joint-ventured in the construction of a drilling rig with NANA and VECO, Inc. This contract also provides for hiring and training of shareholders from these corporations for rig work. ASRC has several subsidiaries that have significant petroleum-related work; among these is Eskimos, Inc. with significant work relating to the exploration of the National Petroleum Reserve -Alaska (NPR-A) through Husky Oil Co. ASRC has estimated that these ventures have employed approximately 200 shareholders in petroleum-related work. For the most part, local residents are employed by local government and by the construction industry (BLM 1978). Currently, the borough has over 500 general government and school district employees, making it the largest source of non-petroleum employment on the North Slope. Unemployment among natives is high, esp~cially during the winter months. Subsistence hunting and fishing is a vital economic activity. Employment of transient non-native workmen is predominantly in the mining industry (petroleum), transportation industry (pipelines), and State and Federal government sector. There is no unemployment in this group because a workman who loses his job leaves the area. Though individual tenure on the North Slope may vary from one to several years, as a rule jobs vacated by non-Inupiat tend to be filled by other non-Inupiat. With the advent of the Beaufort Sea Lease Sale of December 1979, industry at Prudhoe Bay has increased its active seeking of permanent and temporary Inupi at employees, and both ARCO and SOHIO Alaska have active public relations offices in Barrow. Table 3.14-3 shows composite employment statistics for the entire NSB between 1970 and 1977. 3-80 TABLE 3.14-3 J NORTH SLOPE BOROUGH LABOR FORCE ESTIMATES (ANNUAL AVERAGE) 1970 1971 1972 1973 1974 1975 1976 1977 Civilian Resident Labor Force(a) Total Civilian Labor Force 893 822 867 974 1507 1601 1761 1633 Total Unemployment 99 113 102 97 91 105 140 150 Percent of Labor Force 11.0% 13.7% 11.8% 9.9% 6.0% 6.6% 8.0% 9.2% Total Employment 794 709 765 877 1416 1496 1621 1483 Nonagricultural Wa9e & Salary Emeloyment by Place of Work Total Nonagricultural Wage & Salary Employment 977 848 913 1052 1450 1997 6932 5674 Mining 280 119 117 103 290 261 1271 1961 Contract Construction 173 137 104 70 119 380 3738 1472 Manufacturing (b) 0 0 0 0 (b) (b) (b) w Transportation, Communication & Utilities I 86 80 95 168 145 185 316 380 s Trade (Wholesale & Retail) (b) (b) (b) (b) (b) 129 (b) (b) Finance, Insurance & Real Estate (b) (b) (b) (b) (b) 56 (b) (b) Service 142 150 175 187 96 196 445 551 Miscellaneous 0 0 0 0 0 b 0 b Government 165 282 334 395 641 790 892 1078 Federal 128 168 173 171 283 265 239 240 State (b) (b) 142 118 86 93 79 71 Local (b) (b) 19 106 272 432 573 . 766 (a) On place of residence basis (b) Omitted to comply with Alaska Department of Labor disclosure regulations. The Total Civilian Resident Labor Force figures were revised in Spring 1978 to more accurately reflect place of residence of labor force (as opposed to place of work). Break in series between 1973 and 1974; also, revised estimates from 1974 to present are based on North Slope Borough boundaries; previous figures were based on the Barrow Election District. Source: Alaska Department of Labor, Employment Security Division; North Slope Borough (1979). '''"•··'"'"~ It is important to note that the economy of Harrow and the economics of local villages are not directly linked with the Prudhoe Bay petroleum industry. For all practical purposes, there are two separate economies on the North Slope, the oil industry and the indigenous communities. The petroleum industry makes few local purchases of goods or services and very 1 ittle 1 abor (ANF 1979), and all of its product is exported. With insignificant exception, all wage and salary payments to employees are transferred from· the region. The population figures for Barrow shown in Table 3.14-2 show no direct impact of the activity at Prudhoe Bay in the mid-1970s.; ' The North Slope petribleum industry and the local economic systems are 1 inked due to local ;~overnment taxation. The NSB has financed a major public works progra~ and provides substantial public administration employment with propclrty tax revenues derived from the enormous property tax base at Prudhoe Bay. Statewide Total population in Alaska has declined since the peak of oil pipeline construction. Loss of jobs and residents in the Fairbanks and Anchorage areas are primarily responsible for the statewide trend. Table 3.14-4 presents recent population and employment data for Alaska, Anchorage and Fairbanks. High unemployment has been a major problem in southcentral and interior Alaska since completion of the trans-Alaska oil pipeline in mi d-1977. The economy of Fairbanks has been particularly hard hit by a post- p;ipel ine recession. For example, the population of the Fairbanks North Star Borough was approximately 72,000 in 1976, compared with 60,227 in 1978. The 1980 population estimate is approximately 55,000 (Fairbanks North Star Borough 1979). Employment in the borough reached a peak of over 35,000 in late 1975, compared with approximately 21,200 in 1978. PUBLIC FINANCE Revenues from North Slope oil development have benefited both North Slope residents and Alaskans statewide. The NSB has raised revenue primarily from property taxes, while the State has raised revenue primarily from severance taxes and royalty payments. Ndrth Slope Petroleum property located at Prudhoe Bay is an immense taxable resource, and it is through property tax at ion that oi 1 development has had a profound impact on the indigenous people of the region. It is important to note however, that this impact is primarily through capital investment in public facilities and public programs. The material wealth of most village residents is much less than for the typical Anchorage urban dweller. 3-82 w I (X) w ·,·_ ,::.r,·Q:1i+~:'"' J Population( a) (July, 1978) Labor Force(b) (Sept. 1978) Unemployment Rate(b) (Sept. 1978) TABLE 3.14-4 POPULATION AND EMPLOYMENT IN ALASKA, ANCHORAGE, AND FAIRBANKS, 1978 Alaska 423,541 185,831 9.4 Municipality of Anchorage 184 '775 84,186 7 .5, City of Fairbanks 30,462 Fairbanks North Star Borough 60,227 21,211 14.9 Source: (a) Alaska Department of Community and Regional Affairs (1980). (b) Alaska Department of Labor (1978). .,,:, The NSB has over 20 times the per capita assessed value of the Municipality of Anchorage, and over 12 times the statewide average per capita assessed value (including oil and gas property) (Alaska Department of Community and Regional Affairs 1979). Oil property currently accounts for 98 percent of the borough's tax base. The borough • s FY 1979 operating budget was approximate 1 y $79 mi 11 ion, of which 90 percent was derived directly or indirectly from the oil industry (Alaska Department of Natural Resources 1979b). In addition to its expansive public service activities, the borough has launched a major pub 1 i c works program. Over 200; projects are p 1 an ned currently. In the short term, this building program is generating substantial local construction employment. ;,' u Statewide r ,, L Si nee statehood in 1959, A 1 ask a has been heavily dependent upon revenue from petroleum sources. These sources include royalties, production (severance) taxes, lease bonuses and rentals, corporate income taxes on oil companies, and, since 1973, a tax on property used in the production and transportation of oil and gas. Public fiscal dependence on oil development increased substantially after the Prudhoe Bay field was discovered in 1968. In 1979, 69.5 percent of Alaska's unrestricted revenue of $1,178.6 million was from petroleum related sources; 58.7 percent of the State's total public revenue was derived from these sources. The Alaska Department of Revenue (1979) forecasts that these ratios will be substantially higher'in 1980, mainly because of lease sale bonus revenue expected from the B7aufort Sea lease sale (December 1979). High dependency upon revenue from non-renewable petroleum resources is a widespread concern of the State's political leadership and public. A permanent fund was created in 1979 by constitutional amendment in response to this concern. At least 50 percent of mineral lease rentals, royalties, lease sale bonus payments,, and Federal mineral revenue sharing payments must be deposited to the permanent fund. Only the interest from the fund may be appropriated by the legislature. A major objective of the legislature and administration is to stimulate growth of renewable resource industries (fisheries and timber, for example) through investments and special loan programs made possible by oil revenue. 3.15 THE FUTURE WITHOUT THE PROPOSED PROJECT Of all time frames, the future is the most difficult to assess. This is especially true for the North Slope of Alaska, where the rate of environmental change has increased dramatically since oil discovery at Prudhoe Bay in 1968. This section is intended to present a view of the future without the proposed action such that cumulative effects, can 3-84 be clarified. The analysis in this section is to be used in conjunction with Section 4.1, Cumulative Effects. This profile of the future necessarily has greater accuracy for near-future events and areas geographically closer to the Prudhoe Bay primary impact area. Indeed, predictions made in the June 1980 DEIS have been borne out by the time of preparation of this FEIS, namely those pertaining to the "high priority" areas in the Beaufort Sea. The bases of future actions predicted herein for the North Slope have been developed from several facts, including: The Prudhoe Bay discovery underwrote massive capital invest- ment in infrastructure (the PBU enclave) and a secure transportation system (TAPS) of adequate capacity. The rising price and diminishing world supply of petroleum. Deregulation of domestic oil, allowing its price to rise to world market value {which has been driven to date by OPEC). Windfall profits from deregulation and concomitant political pressure on the industry to reinvest in new energy sources. Industry's view of the Arctic (and other continental shelf areas of Alaska) as the most promising region in the United States for new discoveries. Discoveries in the Kuparuk field and Canadian Beaufort that substantiated this view. Along with these facts about future predictions, however, lie uncer- tainties and limitations. These include: The inability to accurately predict commercial discoveries of petroleum, and the timing of their production. Advancements in petroleum technology or petroleum development practice that may occur within intermediate periods of 20 years or less (e.g., enhanced oil recovery techniques; lower- risk production, handling, or transportation techniques). The political and economic uncertainties related to world oil su pp 1 i es. These three factors must be kept in mind because they significantly temper implications or inferences of environmental or social catas- trophe, whether short-or long-term. The purpose of this section, then, is to forecast reasonably likely events. These events are then measured in terms of environmental and social effects --under current conditions (i.e., under current technology). These effects are conditioned by the inability to predict accurately when they will 3-85 occur because timing is predicated on demand for petroleum and economics (return on investment), both short-and long-term. They can be ameliorated and mitigated by sound planning and prudent environmental resource protection that together would allow acceptable development to proceed in a wise fashion. Development and environmental protection within the Prudhoe Bay region exist to a great extent in an atmosphere of conflict. Industry planning faces a maze of regulatory programs that compound the sche- duling problems intrinsic to the Arctic, where missing a construction milestone by 1 or 2 months can mean losing an entire yeiar. Resource agencies responsible for permitting various activiti~s work under mandates often in seeming opposition to one another. An ;~gency charged to protect land finds itself confronting another charged( to lease and develop it. Those charged with the protection of fish,j'wildlife, and habitat are often asked to make decisions with little bas~line data from which to judge impacts. The residents of the North Slop~\are concerned about changes that they view as permanently affecting the viability of the Inupiat people as a distinct cultural entity. The recent establishment of an explicit process that can provide a basis for local and State resource use planning and for the efficient processing of permit applications is an important factor that signi- ficantly tempers the forecast of a lowered environmental quality on the North Slope. The Alaska Department of Natural Resources is a lead agency for this process with the aid of other local, State, and Federal agencies. The adoption of a regional Coastal Zone Management Plan is also assumed. The assessment of cumul:ative effects therefore is based on an open and dynamic process in the future, with sufficient time for resource cl assi fi cation and eval uat iq.n, and appropriately conditioned genera 1 permits. · FUTURE ACTIONS Probable and possible future oil and gas developments between the Colville and Canning Rivers are portrayed in Figure 3.15-1 and the regional context of these developments is shown in Figure 3.15-2. In the regional context, petroleum development in the Canadian Beaufort is quite significant because of its magnitude, projected production date, and environmental factors relating to the U.S. Beaufort Sea. Potential development in the National Petroleum Reserve -Alaska and other areas is also considered. The timing, manpower and construction for each of the probable developments are summarized on Table 3.15-1. Figure 3.15-3 presents graphically the three principal oil and gas pools underlying the Prudhoe Bay area. Several distinct developmental phases for the Arctic can be defined, each of which could expand existing Prudhoe Bay infrastructure (in- cluding service area development) or generate new infrastructure to 3-86 ~ --~-- 1 ----MILES • KILOMETERS 10 ----- 10 20 Note: See Table 3 . t:l-1 for future development specifications. ~.-·-·-. -'"'·~ '" 0 )-·-:-;-.., \ j' .................. "-...-· ~Extent of Currently Leas~d Lands NORTH SLOPE & BEAUFORT SEA OIL & GAS POTENTIAL DEVELOPMENT PBU Waterflood Figure 3.15-1 Environmental Impact Statement i;; ,, w I (X) 1.0 Development Prudhoe Bay1 Specifications Continued Time Frame: Exploration 1980-1985(a) Development 1980-2030 Termination 2030 Recoverable Reserves: Oil (million bbl) 96oo(b) Gas (trillion ft) 26 Peak Manpower Con- struction (Any Year) 2000 Manpower Permanent -- Construction Infrastructure: Gravel Requirements-m3 11,469,000 (yd3) (15,000,000) Number of Drill Pads 10 Number of Platforms 5 Roads -km (mi) 0 Pipelines -km (mi) 0 Number of Airstrips 0 Number of Causeways 0 Land -ha (acres) 800 ( 2000) Production Centers 0 Camps 0 Source: 1 PBU Owners (1980) 2 FERC ( 1979) 3 Oil and Gas Journal (1879, 1980) TABLE 3.15-1 FUTURE DEVELOPMENT SPECIFICATIONS Point Thomson4 Duck Island4 Gwydyr Bay4 Kuparuk3 and Adjacent and Adjacent and Adjacent SGCP2 Field Offshore Offshore Offshore N/A 1980-1985 1980-1986 1980-1986 1980-1986 1981-1984 1980-1986 1985-1995 1985-1995 1985-1995 2030 2000 2015 2015 2015 N/A 1500 250-500 250-500 250-500 N/A __ (c) 0.5-1.0 0.5-1.0 0.5-1.0 1000 400 1000 1000 1000 200 400 300 300 300 2,293,800 5,352,200 4,587,600 3,823,000 3,058,400 (3,000,000) (7,000,000) (7,000,000) (5,000,000) (4,000,000) N/A 10 2-4 2-4 2-4 • N/A N/A 8 8 3-5 <8 (<5) 161 ( 100) 121 (75) 16 ( 10) 24 ( 15) 16 ( 10) 161 (100)(d) 161(100) (e) 24 (15) (e) 32 (20)(e) 0 1 1 1 0 N/A N/A 1 1 1 81 ( 200) 405 (1000) 400 (1000) 320 (800) 320 (800) N/A 1-2 1-2 1-2 1-2 1 1 1 1 1 Notes: (a) Additional exploratory and delineation drilling, mainly in Lisburne formation. (b) Estimated ultimate recoverable reserves. Lisburne reserves not known. 4 Derived from BLM (1979) and Dames & Moore (1978b) (c) Associated gas will be used as fuel and the remainder reinjected into the reservoir. (d) Includes in-field gathering lines and 48 km (30 mi), 41 em (16 in) pipeline to Pump Station 1. (e) Onshore and Offshore. , ,, \ l, i . i 'I 'I lo 'I II lo 'I : I o I I I I I I I I . I I I • • • I PRINCIPAL OIL & GAS FORMATIONS PBU Waterflood Environmental Impact Statement 3-90 Figure 3.15-3 some extent. Tab 1 e 3.15-1 presents project ions regarding principal infrastructural features (e.g., roads, pipelines, etc.), including service area expansion or development. The development phases envisioned include: Continued development at Prudhoe Bay and the Kuparuk field and the construction of the sales gas conditioning plant (SGCP) and Alaska Highway natural gas pipeline system. Development, probably in conjunction with adjacent offshore discoveries, of discoveries on existing State leases such as Point Thomson and Flaxman Island. Exploration and development (assuming commercial discoveries) of offshore tracts sold in the December 1979 joint Federal- State Beaufort Sea· oil and gas lease. These may be developed in conjunction with existing discoveries on adjacent State leases. Three 11 high priority .. areas have been identified where offshore development may take place based on the location of high bid tracts in the 1979 Beaufort lease sale (Figure 3.15-1). These tracts are coincidently adjacent to several exploration units such as Point Thomson and Duck Island where significant exploration has taken place on existing State leases. It is therefore not unreasonable to postulate joint development of adjacent onshore exploration units and 11 high priority11 areas. The recoverable oil and gas resources assumed for these offshore high priority areas are the USGS intermediate estimate of 750 million bbl of oil and 45 billion m3 (1.6 trillion ft3) of gas that have been evenly allocated to each of the three areas (i.e., 250 million bbl of oil and approximately 14 billion m3, 500 billion ft3, of gas). An equal amount of oi 1 and gas has bee11 assumed for adjacent onshore areas (Point Thomson, Duck Island, and Gwydyr Bay). Developments occurring outside the area shown on Figure 3.15-1 in NPR-A and the William 0. Douglas National Wildlife Range (WODNWR) are more speculative. The timing and character of these developments will depend, to a large extent, upon the results of d-2 legislation. No predictions on future developments in these areas have been made except for possible pipeline routes that may take oil and gas production from NPR-A or WODNWR to the trans-Alaska pipeline or to the Alaska Highway natural gas pipeline system (Figure 3.15-2). Further State and Federal lease sales of Beaufort Sea offshore 1 ands. Federal OCS lease sales planned for the Chukchi Sea and the Hope Basin (Figure 3.15-4). Here, new infrastructure (other enclaves like Prudhoe Bay) would be required. 3-91 Development of the Canadian Beaufort in the Mackenzie River delta region. The Canadians have plans to transport petroleum by ice-breaking tanker, at least initially. An industrial interdependency following development across the North Slope, tying each phase together via roads, pipe- lines, shared facilities, and public expectations to produce a lacework whose influence and effect on environmental resources is broader than the acreage and resources directly involved. Prudhoe Continued Production Production at Prudhoe Bay will continue well into the 21st century. Current plans involve installation of a low-pressure separation system, an artificial (gas) lift system, and produced water injection facili- ties. Development drilling at Prudhoe Bay will continue at least through 1985 -1986. Ultimately, in-fill drilling to a 32-ha (80-acre) spacing may be conducted. These additional wells probably would be accommodated by expansion of existing pads and construction of new pads. Additional water injection wells into the gas cap may be devel- oped, requiring new pad construction. Further experience with and evaluation of the Sadlerochit reservoir could result in the need to expand water injection for secondary oil recovery. Such an expansion could conceivably be substantial and entail additional facilities, such as a parallel water treating plant, a third low-pressure water line and high-pressure water lines. An additional injection plant, new injection well pads, and associated gravel might also be needed. >; The Lisburne Formation (see Figure 3.15-3) underlies the Sadlerochit at Prudhoe Bay, and is thought to be more to the north (offshore) and east (across the Sagavanirktok River) than the Prudhoe Bay production zone. Because of its depth and geology (limestone), exploration has been minor. Although reports say some 400 million bbl of oil may be present, it is generally looked to as a gas field more than an oil fieJd. Combining all factors, no development plans are in place at this time. Its depth, however, would facilitate directional drilling and lower the. number of well pads necessary. Its horizontal and vertical proximity to the Prudhoe oil reservoir suggest use of existing pads (or expansions) and a 1 ower requirement for new pads and roads. Natural and man-made offshore islands within the unit have been used in the past and are planned in the near future (1980 -1982). Sohio 'has built one and is completing a second, from which they might reach the high priority area adjacent to the Prudhoe Bay and Duck Is 1 and units (Fig. 3.15-1). 3-92 Of the 99,556 ha (246,000 acres) within the unit, approximately 1036 ha (2560 acres) have been directly disturbed by gravel, with perhaps 243 ha (600 acres) secondarily affected by dust, disruption of drainage, etc. It is foreseen that another 809 ha (2000 acres) might be directly impacted in the future, including 152 ha (375 acres) for gravel mining and 81 ha (200 acres) for service areas. Perhaps 384 ha (950 acres) waul d be wet 1 and (based on percentage analysis from on-1 and waterflood development). Some 11 million m3 (15 million yd3) of gravel would be used for pad expansion, new pads, roads, and gravel islands within the unit. Sales Gas Conditioning Plant and Alaska Highway Natural Gas Pipeline The main facility to be constructed at Prudhoe Bay with respect to the Alaska Highway natural gas pipeline project would be a sales gas conditioning facility located adjacent to the existing CCP. Construction was originally projected to commence in 1981 with the plant completed in 1984. The construction schedule and final design of the Alaska natural gas transportation system remain uncertain pending settlement of pipeline financing and final design. Currently, the system will involve a 1.2-m (48-in) diameter line with a maximum working pressure of 1,260 lb/in2 and initial compression capacity of 67 million m3Jd (2.4 billion ft3Jd} expandable to 90 million m3jd (3.2 billion ft3/d}. For the most part, the line will be buried and adjacent to the trans-Alaska pipeline. Assuming settlement of the financing problem in the near future, a construction schedule of 4 years spanning 1982 -1986 can be envisaged. SGCP construction is expected to require a total of 81 ha (200 acres) of terrestrial development, of which 30 ha (75 acres) would be devoted to gravel mining. No significant expansion is projected for service areas. Approximately 37 ha (92 acres) would be wetland. Gravel needs are estimated at 2.3 million m3 (3 million yd3). Kuparuk Field Development Development of the Kuparuk field, which lies between the Kuparuk and Colv.ille Rivers, commenced in 1979. Estimate of size is 1.5 billion recoverable bbl, which would make it the third or fourth largest field in the United States. The producing formation lies approximately 1829 -2438 m (6000 -8000 ft) deep, which may not allow directional drilling, meaning a far greater number of well pads would be required than in the Prudhoe field. Production should begin at 60,000 bbl/d in 1982, with perhaps two more equal increments following in 1985 and 1986 until production reaches 180,000 bbl/d. The field has no gas cap, implying the need to waterflood on a schedule shorter than Prudhoe Bay• s, perhaps in the late 1980s to early 1990s. As shown on Figure 3.15-1, a permit for a 200,000 bbl/d pipeline route to Pump Station 1 has been applied for. 3-93 Ultimate development could consume 405 ha (1000 acres) of land (including 71 ha [175 acres] for gravel mining and 40 ha [100 acres] for service areas) within an area estimated to be 150,548 ha (372,000 acres) in size. Perhaps 186 ha (460 acres) would be wetland. Approximately 81 ha (200 acres) are currently under gravel; an estimated additional 24 ha (60 acres) are indirectly affected. A gravel requirement of 5.3 million m3 (7 million yd3) is estimated, which includes work pad and road for the pipeline now planned to PS 1. Point Thomson and Offshore Development Exxon Company, U.S.A., the operator of the Point Thomson Unit and owner of several leases in the adjacent high priority area of the Beaufort, plans a sheet-pile encased gravel island at the north end of Point Thomson Peninsula in 1980, with exploratory drilling to begin in 1981. In the high priority area farther offshore, they plan two to three wells to be drilled from pads built on Flaxman and North Star Islands. In the same area, Sohio plans a well from Challenge Island, the western- most barrier island in the area. Existing discoveries at Point Thomson and Flaxman Island may be devel- oped in conjunction with new discoveries made on adjacent offshore tracts. Oi 1 and gas pipe 1 i nes to Prudhoe Bay may be constructed within the corridor sh~wn on Figure 3.15-1. It is assumed that devel- opment of the Point Thomson and Flaxman Island discoveries would be postponed until adjacent offshore discoveries are made. These offshore discoveries are expected to be delineated by 1985. Major facilities ·construction and development drilling would occur during the period 1985 -1995. The Bureau of Land Management judges the Point Thomson/offshore area to be commercial at 500 million bbl. That is, in current economic terms, a 500 million bbl reserve would have to be delineated before production and transportation to market would commence. Assuming this reserve is proved, over a 20-year life the field would produce about 68,000 bbl/d, with each well called upon to deliver 5,000 -10,000 bbl/d. This infers 7 -14 production wells. Based on this scenario, it is assumed that approximately eight explo- ration islands will be needed before reserves are defined. Four onshore drill sites are estimated. Three development islands are forecasted, and it is assumed production would be transported to PS 1 or the closest eastern gathering point via an onshore pipeline. The area is approximately 64,752 ha (160,000 acres) in size, of which perhaps 8 ha (20 acres) are currently directly affected by oil develop- ment, with another 2.4 ha (6 acres) indirectly affected. Ultimately, an estimated 405 ha (1000 acres(· onshore and offshore combined) would be affected, including 71 ha 175 acres) for gravel mining and 40 ha (100 acres) for service ·areas. An estimated 134 ha (330 acres) of 3-94 wetland would be affected. This total acreage includes the forecasted pipeline west to Prudhoe Bay (Figure 3.15-1). Duck Island/Offshore From ongoing activity within the Duck Island Exploration Unit (Figure 3.15-1)~ immediate plans are to have at least three wells underway during 1981 to 1982 in or close to the high priority offshore area adjacent to the unit. These include a man-made gravel island~ a well drilled on Cross Island~ and another from a natural island just south of Cross Island. The Duck Island Unit may be developed along with the high priority area offshore. Nearshore~ development may involve construction of pipeline causeways and onshore lines to Pump Station No.1 and SGCP. Further offshore~ production might be de 1 i vered vi a subsea pipeline~ ultimately to Pump Station 1~ or it might be shipped by ice-breaking tanker (see discussion under Canadian Beaufort Sea Development). Major field development is assumed to commence in 1985 and continue through 1995. This area covers about 54~634 ha (135~000 acres)~ the majority offshore. Exploration now underway and immediately planned affects perhaps 8 ha (20 acres)~ of which another 2.4 ha (6 acres) may be indirectly affected. Assuming commercial reserves must range from 200-500 million bbl~ ultimately 324 ha (800 acres) would be directly affected~ including 51 ha (125 acres) for gravel mining. No significant expansion is projected for service areas. Total wetlands affected may be approximately 16 ha (40 acres). Gwydyr Bay and Stump Island Discoveries made on the Gwydyr Bay Exploration Unit may be developed along with those made in the adjacent high priority area located seaward of Stump Island~ or in Milne Point to the west (Figure 3.15-1). Pipelines would be constructed to Prudhoe Bay Pump Station No. 1 and SGCP. As with the Point Thomson and Duck Island discoveries~ it is assumed that it takes about 5 years to discover~ delineate~ and make the necessary feasibility assessments before field development in this area can commence. This area covers about 23~068 ha (57~000 acres) of river delta~ barrier islands~ and marine waters. Approximately 4 ha (10 acres) are currently affected directly by exploration activity~ with another 1.2 ha (3 acres) indirectly involved. Ultimately~ perhaps three to five man-made offshore islands would be built for exploration and expanded for production; however~ industry will prefer to use barrier islands. Some 324 ha (800 acres) might be directly affected should production take place~ including 40 ha (100 acres) for gravel mining and 324 ha 3-95 (800 acres) for service area. Wetlands affected may total approxi- mately 40 ha. Production would be transported by pipeline to the nearest gathering point on the west side of the PBU. Development of NPR-A and WODNWR If exploration should commence in WODNWR and continue in NPR-A and commercial discoveries result, production from these areas would probably be piped to Prudhoe Bay for transport in the trans-A 1 ask a pipeline or Alaska Highway natural gas pipeline (Figure 3.15-2). In the area between the Canning and Colville Rivers, the principal developments resulting from discoveries in NPR-A and WODNWR will be construction of pipelines to Prudhoe Bay that would be located in the pipeline corridors already developed for the Point Thomson and Kuparuk fields. Future Oil and Gas Lease Sales Both State and Federal governments have aggressive oi 1 and gas leasing plans for the Arctic through 1985. Three Federal OCS lease sales are scheduled for arctic waters; three State sales (two in the Beaufort Sea and one in the Prudhoe Bay uplands) are scheduled as well. In early 1981, the State plans to offer for sale leases in the Prudhoe Bay uplands, an area bounded by the Canning and Colville Rivers, between Deadhorse and Sagwon (Figure 3.15-2). The State reports industry interest to be high, with petroleum potential judged moderate. The area has been explored in the past without significant success. In early 1982, the State has scheduled a second Beaufort Sea lease sale, which includes submerged lands to the 3-mi 1 imit, not offered in the first Beaufort sale in 1979, and some new acreage. Industry interest is reportedly very high following the potential for oi 1 and gas. The proposed area runs the coastline from Barrow to the Canadian border; however, the ownership of land offshore of NPRA and WODNWR is disputed by the State and Federal governments and these areas may not be offered. Along its current schedule, the Federal government plans a second Beaufort Sea sale the following year for submerged land beyond the 3-mi limit. The Federal area of call is the same as the State•s, but the BLM has identified blocks for further study (Figure 3.15-2). In 1984, the State plans to sell Beaufort Sea tracts not offered or not leased in 1981. In February 1985, the Federal government proposes to sell offshore leases in the Chukchi Sea --contingent upon suitable technology being available for exploration and development. In May 1985, a separate sale is planned for the Hope Basin. 3-96 Exploration by Arctic Slope Regional Corporation Headquartered in Barrow, the Arctic Slope Regional Corporation (ASRC) is an Inupi at profit-oriented corporation formed under the A 1 ask a Native Claims Settlement Act of 1971. ASRC is active in many enterprises, petroleum exploration being one. It has entitlement to 1.6 million ha ( 4 mj ll ion acres) within the North Slope Borough. To date, it has drilled three unsuccessful oil wells in the Arctic Foothills; others are planned in the future, but specific plans are unknown. Canadian Beaufort Sea Development In 1972, Canadian petroleum exploration stepped offshore from the Mackenzie River delta into the shallow water (3m, 10ft) of the Beaufort Sea. Using gravel islands, the industry reached depths of 20 m (65ft), 26 km (16 mi) from shore. To date, 17 islands have been constructed for exploration. By 1976, Canadian Beaufort exploration was· underway in water more than 30 m (100 ft) deep, using ice-strengthened drillships. In 1977, one well (Kopanoar D-14) was abandoned at 1158 m (3800 ft) after encoun- tering high-pressure formation water, which rose to the seafloor outside the casing. By the time a relief well was drilled, however, flow had ceased. That same year, another well (Tingmiark K-91) was shut in after striking a high-pressure gas zone. Subsequently, saltwater was discovered leaking from a seafloor fissure very near the wellhead. Three drillships were operating in Canadian waters in 1978, with a fourth scheduled to join them the following year. These ships can drill to nearly 6097 m {20,000 ft) in water nearly 305 m (1000 ft) deep (Dames & Moore 1980a). In 1980, Dome Petroleum plans six new wells in the Canadian Beaufort, spurred by successes such as 12,000 bbl/d from one zone of the Kopanoar structure. Confirmation wells are scheduled for 1980 and 1981. With favorable results from these wells, Dome expects to deliver oi 1 to markets by 1985 via ice-breaking tankers. The Kopanoar structure is expected to prove out.at 1-2 billion bbl (comparable to the Kuparuk field), and Dome looks at production of ·some 400,000 bbl/d (giving the structure a 10-year life). So far, Kopanoar is the only structure close to proven commercial reserves. However, in a study report (Dome 1980), the company projects an ambitious scenario of future oi 1 development in the Canadian Beaufort that leads to proven reserves of 16 billion bbl by the year 2000, located in 12 offshore oil fields. These would be produced at 3 million bbl/d by 1999 (twice the current production rate of the Prudhoe Bay field), requiring 24 gravel islands (each 30 ha [75 acres] in size) to accommodate 40 -60 wells, each with tanker berthing. In the early years of the fields, oil would be delivered by 10 -20 ice-breaking tankers of 1.4 million bbl capacities. Dome estimates this mode could 3-97 deliver 50,000 bbl/d to east coast markets. Each tanker would be making roughly 16 trips per year through the northwest passage. Once production reached 750,000 bbl/d, a pipeline would be economic, although the tankers would remain in service. The sale and transport by tanker of petroleum to Japan via the Bering Straits is a possibility being reviewed by Canadian companies at present. Interrelationship of Arctic Development Nodes Development beyond the PBU is synergistically related to the Prudhoe Bay oil discovery that underwrote the necessary support and transport at ion infrastructuree, i.e., the PBU enclave and TAPS. Without it, none of the developments described above and in Table 3.15-1 could occur, since none is economically viable on its own merits. Acting together, the increasing price of oil, world politics, and increasing world demand for energy make projects possible that otherwise would be marginal if not infeasible. In this light, a concept of 11 expanding development horizons .. becomes clear. This concept is developed because it is important in predicting cumulative effects in the Arctic. The Kuparuk development exemplifies this concept. Perhaps the third or fourth largest field in the United States, it was but marginally .commercial until recently. A road now links the Kuparuk to the PBU, and a pipeline to PS 1 is planned. The Kuparuk is 16 percent the size of Prudhoe Bay, and if this relationship were linear (which is unknown), then less than a 3 mi 11 ion bb 1 development waul d be necessary for an equal distance west of the Kuparuk to prompt development and production in this direction, including an east-west pipeline link. Thus, as pipelines and infrastructure progressively link high production develop- ment nodes, less viable intervening areas become far more economically feasible and would likely be proposed for development. FUTURE ENVIRONMENTAL AND SOCIAL PROFILES The following profiles were developed to place the effects of the proposed Waterflood Project in context. Prediction of effects is problematic, however, because of the expected rapid pace of development and the need to assimilate results of scientific study. It is evident froin Figure 3.15-1 that the vast majority of projected development will occur on the Arctic Coastal Plain or along the continental shelf of the Beaufort and Chukchi Seas, an area of intense biological activity seasonally and one supporting biological resources of considerable economic, ecologic, and cultural value. Wet 1 ands The projected development as portrayed in Figure 3.15-1 would occupy some 2325 ha (5750 acres) of arctic coastal plain, 1400 ha (3450 acres) 3-98 of which would probably be wetland habitat. It is likely that alter- ation of the more valuable wetland types would tend to be avoided in lieu of wetlands with less habitat value, assuming existing trends in environmental protection and planning continue. Nevertheless, airstrips {three projected) and the networks of roads and pipelines would disrupt habitat continuity, and cause local alteration to surface drainage and local changes in wetland characteristics. The cumulative disturbance of noise, activity, and dust would reduce the habitat value of wetlands adjacent to development areas ·for a variety of species. Net Primary Productivity (Terrestrial) Perhaps 2325 ha {5750 acres) of vegetated terrain would be lost as a result, of the projected petroleum development activities (e.g., covered with gravel). An additional reduction in productivity would occur adjacent to facilities due to dust and ponding. The amount of disturbed terrain in relation to the total land area is very small on a percentage basis. Potentially greater effects on primary productivity may occur if major interruptions in surface water drainage result from development. It is possible, however, that such interruptions may be prevented by adequate environmental planning. Net primary productivity can be viewed as a quantitative indicator of the direction of change in the natural environment. Marine· Area Marine habitats would be altered primarily by the construction and operation of offshore platforms and causeways (Table 3.15-1). ·sedimentation resulting from offshore dredging, gravel placement for islands and causeways, or other in-water activities (e.g., vessel prop wash, "drilling mud and cuttings disposal, etc.) would temporarily affect local populations of benthic organisms, especially less motile forms. Water quality would probably deteriorate as a result of discharges, accidents and developments within local drainage basins. The three causeways projected for construction would affect water quality and fish migrations near shore in the same ways as the existing Prudhoe Bay West Dock. Waterflooding of other formations, as well as other industrial water use requirements, are 1 i kely. Marine organisms 1 i kely to be greatly affected by the projected development are marine and anadromous fish, opportunistic invertebrates (e.g., scavengers, fouling organisms), birds, and marine mammals. Development in the Canadian Beaufort would probably affect fisheries resources of the Village of Kaktovik. Also, because of the clockwise gyre in the Beaufort Sea, oil spills in Canadian waters could affect coastal waters of the U.S. Marine biota may become increasingly stressed because of these developments. Waterbirds Wetland habitats utilized by waterbirds would be reduced by a small percentage. Projecting figures developed for Prudhoe Bay by Connors and Risebrough (1979), loss of 2325 ha (5750 acres) of tundra habitat 3-99 ; would result in direct displacement of some 2250 -4500 pairs of shorebirds. Ducks and geese would also be displaced. Continued disturbance resulting from ground, air, and marine activities would have additional adverse impacts on bird populations as long as the sources of disturbance exist. Pr.oliferating activities in the coastal region would probably have the greatest effect due to species concentrations and east-west movements along the coastline. The probability of an oil spill in the marine environment would increase as offshore drilling, production, and other offshore activities accelerate, thus increasing the likelihood that marine birds and waterfowl would be adversely affected. Marine Mamma 1 s Marine mammals may be significantly affected by continued North Slope development, particularly offshore. Increased ship traffic to and from the development area might have a brief disruptive effect on whale migrations, but the probability of encounters detrimental to even individual whales is judged to be low. Species that shun areas of intense human activity or accidental discharge of toxic materials would suffer a loss of habitat due to behavioral responses. Spatial shifts in populations would adversely affect subsistence hunters. · Caribou Deve 1 opment of petro 1 eum resources between NPR-A and the WODNWR waul d involve an east-west road and elevated pipeline up to 483 km (300 mi) long. Current evidence suggests that traditional north-south caribou movements would not be blocked completely by this corridor. However, the physical presence of the road and pipeline, along with associated noise and activity, would alter caribou behavior. Prior to 1974, occasional east-west movements of caribou (probably the Porcupine herd) were observed through the Prudhoe Bay Unit. All trail patterns in the tundra suggested that such activity also occurred in earlier years. More recently, caribou migration through Prudhoe Bay has been reduced. The high potential for petroleum development in Naval Petroleum Reserve -Alaska could result in similar effects on the Arctic caribou herd to the west and increasing influence on the Porcupine caribou herd to the east if there are significant discoveries in the Point Thomson Unit, the William 0. Douglas National Wildlife Refuge, or in northern Yukon Territory, Canada. Use of traditional calving and insect refuge areas near the coast may gradually diminish, causing a reduction in useable range. Disturbance of caribou would be greater near intense development areas such as producing field and shore bases. Whether or not development, as projected to year 2030, would have extensive long-term adverse impacts on the three caribou herds that utilize the North Slope is difficult to predict, but significant negative .impacts are possible. 3-100 Water Quality and Availability Escalating human population and industrial activity through the year 2030 would increase the likelihood of adverse impacts on water quality through human waste, water demand and industrial accidents. It is likely that existing environmental protection regulations, in combi- nation with the natural flushing that occurs each summer on the coastal plain, would prevent significant area-wide chronic deterioration in water quality. Some localized short-term impacts would probably occur as a result of specific oil spill incidents. Adverse impacts to water availability from projects such as the SGCF, gas line, Kuparuk field, and Beaufort lease sale appear to be unlikely. Annual freshwater use associated with Beaufort Sea development will peak at 227,000 m3 (60 million gal) in 1989, and gradually reduce until 1999 and 2000 when water use will be 23,000 .m3 (6 million gal) (BLM 1979). Aesthetics Development on permafrost terrain necessitates maintaining thermal integrity, traditionally accomplished with thick gravel overlays. The resulting network of roads, pipelines, and other facilities is highly visible, especially from the air, and cannot be rehabilitated to a completely natural state. Drilling rigs, gathering centers, injection plants, and other production facilities typically require multi-story structures that are vi~ible for many miles in the generally flat terrain. Projected development through year 2030 would expand the scope of petroleum activities and consequently increase aesthetic impacts. These effects would be most significant where new production nodes are developed and interve~ing transportation and development occur. Traditional Inupiat Culture Projected developments will produce significant and continuous pressure upon the traditional culture of the Inupi at. As economic exploitation of this continued development by Inupi at-owned and controlled . organi- zations and companies becomes a 1 arger factor in the adaptive strategy of the Inupi at, internal as well as external pressure for change will increase. The extent to which the Inupiat are able to continue a mixed economy based upon cash and subsistence depends upon long-range management of biotic resources and the economic opportunities as viewed by the Inupiat themselves. Development of a Tribal Employment Rights Office at !CAS and the activity of the several native corporations now involved with petroleum:development or planning such involvement may bring more Inupiat into the direct employ of industry. Continued growth and economic activity and opportunity provided by the NSB and by the regional and village corporations will provide another source of internal stress to traditional Inupi at culture. However, it should be noted that these entities have made efforts to allow appropriate time for subsistence pursuits to employees. This positive 3-101 response can be inherent to an Inupi at-controlled entity and provide a source of support for traditional organization and social activity . Wilderness Value Because the projected development would affect such a large area, much of which is now undisturbed, it is expected that wilderness values would be substantially reduced over the next 50 years. Although 1 arge areas of undisturbed wilderness would remain on the North Slope, the east-west transportation corridor and various site-specific developments (see "Aesthetics" above) would make significant inroads. The various aspects of the meaning of wi 1 derness would change for a 1 arge area of 1 and and water. Because the North Slope is essentially a treeless plain, vistas commonly extend for many miles. In areas of future development beyond Prudhoe Bay, these vistas, the solitude that now exists, and the feeling of oneness with nature that now overwhelms these areas will be broken by drill rigs, gravel pads, and pipelines. --- 3-102 -.. .. • ;ro- CJ Ill 0 z 0 (.) CHAPTER 4.0 ENVIRONMENTAL CONSEQUENCES This chapter provides a detailed discussion of the potential physical, biological, cultural, and economic effects that would result from the construction and operation of the practical alternatives, including the proposed project. This discussion is derived from the descriptions of the proposed action and its alternatives in Chapter 2.0 and of the affected environment in Chapter 3.0. This chapter supports the brief analysis of alternatives and associated impacts presented in Chapter 2.0. The first section of this chapter summarizes the relationship between short-term use and long-term productivity of the area, the benefits, unavoidable environmental impacts, the irreversible and irretrievable commitments of resources, and the cumulative impacts of the proposed project with those of other regional developments. The second section provides a comparison of the impacts of the proposed project with those of the major feasible alternatives. Adverse impacts to various aspects of the Prudhoe Bay environment would result from each of the waterflooding alternatives considered. No such impacts would result from the no action alternative or from the national alternatives. Secondary recovery alternatives to waterflood are not considered viable at this time and are not treated here. 4.1 EVALUATION OF PROPOSED PROJECT The major impacts of the proposed Waterflood Project are summarized below. These and lesser impacts are described in detail in Section 4.2. along with the impacts of viable alternatives. PROJECT BENEFITS , The major benefit that would be derived from the proposed project would be the increased recovery of crude oil from the Sadlerochit Formation. Estimated additional recovery of some 1 billion bbl would constitute a significant contribution to domestic oil reserves. The labor force, and goods and services required to construct and operate the project would stimulate local economies. The value of the produced oil and gas to the owner companies would be considerable. Likewise, the State would accrue significant tax revenues. UNAVOIDABLE ADVERSE IMPACTS Approximately 106 ha (263 acres) of terrestrial habitat (including 60.1 ha, 149 acres, of wetlands), and 27 ha (67 acres) of seafloor habitat would be unavoidably lost as a direct result of the project. Also, there would be an unavoidable reduction of value for an estimated 4-1 4680 ha (11,600 acres) of terrestrial habitat and approximately 1670 ha (4130 surface acres) of marine habitat. These effects are briefly explained below. A direct loss of biological productivity, roughly in proportion to the habitat loss, would result. Ocean currents and waves would be deflected by the causeway extension, resulting in changes in water quality and shoreline configuration. Potential impacts would be the ex pans ion of Stump Is 1 and to the east, reduction in flow through eastern Simpson Lagoon, periodic increases in salinity to the west of the causeway extension affecting some 1670 ha (4130 acres) of lagoonal habitat, and corresponding reductio·ns in salinity to the east of the seawater treating plant. Approximately 68 ha (168 acres) of tundra adjacent to new roads and pads would be indirectly adversely affected by dust during construction and operation. Additional area adjacent to existing roads and pads also would be affected by increased dust during construction and by increased traffic during operation. Other adverse impacts to the tundra ecosystem would result from ponding of water near new roads and from accidental saltwater spills. Wildlife access (and thus an element of habitat quality) would be reduced on approximately 4600 ha (11,400 acres) east of the proposed western pipeline and road. In the present case, however, these changes would occur in close proximity to existing development; therefore, potential adverse effects would be les!)ened. The causeway extension, and perhaps associated changes in circulation and water quality, would alter sediment and invertebrate distribution patterns and form a partial barrier to migrations of marine and anadromous fish. Plankton and small fish (<100 mm in length) entrained by the intake would be destroyed as would some fish passing throqgh the intake system. Chlorination products, some of which could be td:Xic to marine organisms, might accumulate in sediments near the discharge diffuser during the winter. Water quality would be reduced within a 40-ha (100-acre) mixing zone. Caribou would be disturbed somewhat by the construction of onshore structures (e.g., roads and pads). The reduction of subsistence resources caused by habitat changes, reduction of species populations through direct mortality and behavioral changes, and restrict ion of hunting and fishing area probably would unavoidably increase the pressure for change of the traditional Inupiat life-style. In the long term, this may act to reduce the adaptability of the culture to arctic life after petroleum development is abandoned and cash flow is reduced. A quantitative estimate of the reduced availability of subsistence resources for the area villages cannot be made, but measurable impacts due to this project alone are considered unlikely. However, future projects could act cumulatively with the proposed action to make such reduction significant. A program for resource classification, evaluation, and planning on the North Slope could do much to reduce these cumulative effects to acceptable levels while allowing for 4-2 efficient development. The Alaska Department of Natural Resources has indicated that it intends to be lead agency in developing this program. Placed in the perspective of impacts that have already occurred, or will occur without the project, unavoidable adverse environmental degradation associated with the proposed 1 and modifications waul d be relatively minor with the possible exceptions of that resulting from the proposed new road and pipeline betweeen Well Pad K (Term Well A) and Well Pad E. However, environmental degradation related to the proposed causeway extension and seawater intake are judged to be more significant. SHORT-TERM USE VERSUS LONG-TERM PRODUCTIVITY In the short term, the proposed project would allow use of some 1 billion bbl of crude oil. However, various aspects of the proposed project would cause environmental changes that would affect the bio- logical productivity of the area long after project abandonment. Tundra lost due to gravel placement and gravel extraction would remain out of production or at a low productivity level over the long term. Drainage pattern alterations (ponding, dewatering), and thermokarsting would also produce long-term changes in productivity. Anticipated reduction in caribou use in the area east of the road between the module staging area and Well Pad E would continue but might be ameliorated by pipeline and road pad removal during project abandonment. On the other hand, additional development on the North Slope may well result in continued heavy use of this road long after the Sadlerochit water- flood has ceased. The State of Alaska (Comments on DEIS, Vol. 3) has noted that, while the Central Arctic caribou herd has recently been increasing, east-west movements during summer no longer extend through this area to any great extent. Migrating waterfowl and wading birds that depend on arctic habitats may experience a slightly lower rate of productivity. This long-term reduction may affect the human environment in parts of the western hemisphere quite distant from the primary~impact area. IJJ the marine environment, causeway-induced increases and decreases in local productivity would continue as long as the causeway remained in place. Natural erosion of the causeway would tend to return the near- shore configuration, circulation, water quality, and productivity to a more natural state, perhaps forming a gravel spit-island complex. Areas covered by gravel fill would be removed from productivity unless and until erosion lowered the fill elevation below levels reworked by "normal" waves. Once these areas became relatively stable, their productivity may increase, possibly equaling or exceeding that of other similar habitats in the area. 4-3 IRREVERSIBLE AND IRRETRIEVABLE COMMITMENTS OF RESOURCES Irretrievable commitments of natura 1 resources would include seawater, oil, gas, gravel, fish, birds, caribou, and other organisms. Approxi- mately 2.55 km3 (0.6 mi3) of seawater would be consumed over 20 years by injection into oil-bearing strata. Oil would be consumed by vehicles and other equipment that would be used during construct ion and oper- ation, and natural gas would be consumed by the turbines and heaters required by waterflood. An energy equivalent of approximately 50 -100 million bbl (5 -10 percent of expected recovery) of oil would be expended during construct ion and operation of the proposed project. Based on 1 imited avail able data, impingement and entrainment by the seawater intake would cause a loss of fish eggs and fish larvae during 20 years of waterflooding (Appendix H). Additional losses of fish productivity would probably result from causeway-delayed migrations .. Some loss of productivity by benthos, waterfowl, shorebirds, and caribou would be expected due to disturbance and loss of habitat. Approximately 106 ha ( 263 acres) of natura 1 tundra would be buried under pads and roads. A somewhat greater area also would be altered by ponding and dust deposition. Recovery rates of tundra are sufficiently slow that this loss, except for that attributable to dust, would be irreversible within a period of several decades. Waterfowl, fish, and marine mammals numbers could also be reduced slightly by reductions in food and habitat changes. Under worst-case assumptions, reductions of local fish populations may be as much as 4 percent of present levels. A reduction of 2 percent or less, however, is more probable. CUMULATIVE IMPACTS Assessing the cumulative effects of the proposed Waterflood Project is problematic. Both positive and negative effects have been identified. This task is made difficult by the rapid pace of environmental changes in the Prudhoe Bay area during the 1 ast decade and the potential for considerable development of other areas on the North Slope and the Canadian Arctic within a relatively short time. (Section 3.15 is the reference base for most Waterflood Project cumulative effects. It should be used in conjunct ion with this sect ion so that future arctic development and waterflood are in context.) Furthermore, certain effects of decisions about North Slope oil development influence conditions (geographic, economic, and social) in other areas of the world quite distant from the Arctic Coastal Plain and Beaufort Sea. It is reasonably beyond the scope of this EIS to trace all effects and reveal the many possible intercontinental biological and social changes resulting from development on the North Slope. Indeed, it is beyond the state-of-the-art. The approach taken was to concentrate on certain key indicators including: North Slope crude oil distribution and the mix of foreign and domestic oil supplies; migratory waterfowl and wading birds that depend on natural ·systems in the Prudhoe Bay primary impact area; caribou; polar be~r; and anadromous fish. Stress on traditional native 4-4 culture was estimated by assessing changes in the subsistence resource base and the economic resource base. Reference should also be made to the EIS on the Beaufort Sea Lease Sale (1979 -1980 BLM/OCS) for more information on cumulative effects. It is important to note that the assessment of cumulative effects assumes an open and dynamic process in the future with sufficient time for resource classification, evaluation, and with appropriately conditioned general permits (see Section 3.15). The Alaska Department of Natural Resources has indicated its intent to lead this process. Public involvement is expected to commence shortly. Cumulative impacts could result from interaction of proposed waterflood- rel ated impacts with impacts from any of the following North Slope development projects: continued or expanded production within the PBU, including increasing the number and size of drill pads, roads, airports, pipelines, service facilities, gravel mines, and seawater treating and distribution systems; _the sales gas conditioning plant; Alaska natural gas transport at ion system; exploration and development of the Kuparuk, Gwydyr Bay, Duck Island, Milne Point, Point Thomson, and other State and Federal lease areas on 1 and and in the Beaufort Sea; the National Petroleum Reserve -Alaska; Canadian arctic development; and the Arctic Slope Regional Corporation oil and gas leasing (see Figure 3.15-1). In addition, once the waterflood of the Sadlerochit Formation has begun, there are several factors that indicate the need for possible future expansion of this project: 1. Only about half of the developable acreage has been drilled to date. Further drilling could indicate the need for additional waterflood volumes. 2. Actua 1 waterfl ood performance may indicate benefit from additional water injection volumes. 3. Gas cap waterflooding may be of benefit in oil recovery. 4. Optimum deyelopment of the west end portion of the Prudhoe Bay field may require waterflooding. 5. Waterflooding of Lisburne or other Prudhoe Bay Unit horizons may be indicated in the future. None of these factors can be accurately assessed at the present time, but all represent potentially viable future possibilities. Because an expansion could take various forms (as cited above), it is not possible to be specific at the present time as to the volume and location of additional water injection. The following, however, would appear to be not unreasonable assumptions for purposes of an environme~tal impact evaluation: 4-5 ; 1. Up to a 50 percent expansion in total volume of source water should be considered; i.e., a 1 mill ion bbl of water per day expansion. 2. An additional platform would be required for seawater treatment expansion facilities, located at the end of the presently proposed causeway extension or adjacent to an island (if it is ultimately permitted) and situated in a gravel berm next to the currently planned seawater treatment plant. 3. The currently proposed causeway extension should suffice, with only relatively minor modifications (i.e., expansion of the causeway end and burial of additional pipeline), for the expansion facilities. For the island alternative, additional dredging would be required. 4. One additional injection plant, similar to the two currently planned, could be assumed. For planning purposes, this plant could be assumed to be centrally located in about the area of the current Central Compressor Plant (CCP). 5. Since the injection locations are unknown, the amount of gravel could be estimated by assuming a 50 percent increase over current plans for the onshore portion, commensurate with the 50 percent increase in source water inject ion volume. It should be assumed that, to the extent feasible, existing gravel pads would be expanded rather than new ones constructed. The proposed Waterflood Project waul d have both beneficial and adverse cumulative effects. Beneficial effects relate to the 1 billion bbl of oil produced and the possible refuge function of oil production areas. The project, added to other North Slope crude oil production efforts, would enhance the efficiency and economics of area-wide production and transportation systems (including the trans-Alaska oil pipeline). Considered in light of the significant national need for low-cost energy, the increment of domestic oil and gas produced by the proposed project would be valuable in view of the current and near-future world oil supply situation. The proposed project probably would also act synergistically to improve economic conditions in Alaska. No hunting is allowed in production areas; therefore, some incidental refuge value may be gained (i.e., animal mortality would tend not to be attributed to hunt in g). Adverse cumulative effects waul d result where a given population of organisms or man uses habitats or other resources degraded by two or more of these projects. Cumulative losses of marine or terrestrial habit at supporting the same populations of organisms waul d jointly deplete these populations and perhaps decrease their potentia 1 maximum numbers. 4-6 Arctic fish and wildlife characteristically move great distances (many on an international scale) and depend on specific ecosystem elements or processes within a compressed time frame. Individuals of migratory populations, especially waterbirds, caribou, anadromous fish, and polar bears, which are in search of food, denning or overwintering areas, molting areas, calving grounds, or breeding areas, would be especially vu 1 nerab 1 e. A spec i a 1 dependency on the 1 and and offshore areas of the Beaufort coastline has developed during the evolution of these species. The Inupiat people, in turn, developed a culture heavily dependent on many of these coastal-oriented migratory species. This culture has endured, in part, to the present and is among the most important factors to be considered in assessment of cumulative develop- ment impacts on the North Slope. Changes will continue to challenge the adaptability of the North Slope people. While these changes represent additional cultural pressures, they need not be viewed as entirely negative. Although the incidence of alcohol abuse, violence, and other indicators of social stress will be evident, the opportunity for training, education, employment, ipcreased public services, and productive interchange with industry and government will also occur, thus increasing the chances for the Inupiat to achieve their long-term cultural goals. The cumu 1 at i ve effects on key e 1 ements of the environment described in the following subsections have been derived primarily from super- imposition of likely impacts that would accrue from the Waterflood Project on impacts projected to result from the North Slope development scenario expected to occur even in the absence of this project (see Section 3.15). Included in this discussion is the potential 50 percent expansion of Prudhoe Bay waterflood facilities as described above. Terrestrial and Wetland Habitat The Waterflood Project (as expanded) would increase the projected area of terrestrial habitat directly occupied (e.g., by work pads, roads, drill pads, support facilities) by some 5 percent (3525 ha [8700 acres] total vs 3365 ha [8315 acres] for other developments [see Table 3 .15-1], including areas already developed at Prudhoe Bay, but without waterflood). The majority of this habitat loss (about 2080 ha [5140 acres] including some 1040 ha [2560 acres] already lost) would be in the Prudhoe Bay area. About 60 percent of this area would be wetlands. Although a sma 11 fraction of the above coverage wou 1 d be in areas now permanently covered with water (1 akes, ponds, and streams) it can be assumed that primary production of vegetation would be lost from the entire 3525 ha. This amount of disturbed terrain is very small on a percentage basis in relation to the total land area; the amount of the loss contributed by waterflood is again 5 percent of that fraction. Potentially greater effects on primary productivity would occur if major interruptions in surface water drainage resulted from development. Experience at the Prudhoe Bay field indicates that blocked drainage and subsequent flooding is apparently difficult to control. Therefore, adverse effects of development extend to a greater area. An additional 4-7 • reduction in productivity would occur adjacent to facilities due to dust and thermokarsting. It is unlikely that loss of primary productivity, by itself, would have significant adverse effects on any bird or wildlife populations (i.e., by reducing food availability). However, the cumulative modification of total habitat and disturbance of noise, activity, and dust adjacent to development areas would reduce the habitat quantity and value for a variety of species. Changes in net primary productivity, therefore, can be used to indicate ecosystem changes and, when merged with other elements of habitat, the effect on species groups can be estimated. Waterbirds By projecting the figures developed for Prudhoe Bay by Connors and Risebrough (1979), it is estimated that a loss of 3525 ha {8700 acres) of tundra habitat would result in direct displacement of some 3400 - 6800 pairs of shorebirds. Again, some 5 percent of this loss would be contributed by the expanded Waterflood Project. Ducks and geese waul d be similarly displaced. Disturbance resulting from ground, air, and marine activities of the Waterflood Project would have a slight adverse impact on bird popula- tions over that caused by other developments. Proliferating activities in the coastal region would probably have the greatest effect due to species concentrations and east-west movements along the coastline. Within this coastal area, river deltas are especially sensitive to development because of the concentration of waterfowl and anadromous fish. However, since most waterflood activities would be in areas already affected by development, the contribution to the total impact would be disproportionately small (as compared to development in heretofore unaffected areas). The probability of an oil spill in the marine environment would increase as offshore drilling and other offshore activities accelerate, thus increasing the 1 ikel ihood that marine birds and waterfowl would be adversely affected. The Waterflood Project would not greatly influence oil spill risk except for the increased volume of oil available for pipeline transport. Caribou Cant inued coastal development (especially of east-west transport at ion corridors) can be expected to reduce caribou access to coastal regions important for insect relief and calving. Of the proposed project facilities, only the proposed new road section between Well Pads K and E is 1 ikely to influence current caribou movement patterns. Because the proposed project would modify habitat in close proximity to existing development and because current use of this area is low, the contri- bution of the proposed project to cumulative impacts on caribou would be minor compared to cumulative past and future actions without waterflood . 4-8 rT I I I I I I; ,, !~ ~ Gravel The overall development scenario for the U.S. Beaufort Sea coastal zone indicates a need for some 45 mill ion m3 (59 mill ion yd3) of gravel (Table 3.15-1 sum, plus that already used in Prudhoe Bay, plus that required for the proposed project increased by 50 percent). Of this, some 8.4 percent would be required by the expanded Waterflood Project. Although the needs of the proposed Waterflood Project could be met from existing sources in the PBU, use of this gravel for the Waterflood Project will ultimately increase the need to open new mines. Because much gravel extraction occurs near rivers, the environmental effect of such activity is heightened. Future use of buried ancient river valleys may reduce this effect. Environmental planning related to gravel mining is a greatly needed element in planning for continued development. Without such efforts, gravel mining will continue as an unresolved issue in the future. It is assumed, however, that the planning process and resulting products instituted by the Alaska Department of Natural Resources will reduce this controversy and potential adverse effects of mining. It is also assumed that offshore gravel mining will be conducted in a manner compatible with life cycles of endangered species. Marine Habitat The projected overall development of the North Slope would alter marine habitats primarily by the· construction and operation of offshore plat- forms, causeways, and seawater intakes. Construct ion impacts, except for the area of productive seabed buried by gravel placement, would be short term and not likely to accumulate. Placement of gravel offshore for the Waterflood Project might well contribute up to 10 percent of the total projected offshore seabed to be covered by development (depending on the extent of offshore gravel island development) but would represent an insignificant loss of benthic habitat when compared to the total area present. Extension of the existing Prudhoe Bay causeway in conjunction with construction of up to three additional causeways (Table 3.15-1) could cumulatively delay anadromous fish migrations to the point where move- ment to overwintering and spawning areas is significantly impaired. Distributions of food resources could also be altered. While lacking information on the specific location and orientation of these additional causeways, the proposed extension could be assumed to cumulatively contribute approximately 25 percent of any anadromous fish population losses due to construction of these causeways. Effects of possible future waterflood expansions include the potential discharge of up to 50 percent greater quantities of pollutants and entrainment/entrapment biotic losses up to 50 percent greater than for the current project alone. Also, waterflood activities in the Canadian Beaufort may take additional resources. 4-9 In the worst-case scenario developed later in this Chapter, the proposed extension of the existing causeway is presumed to cause a mortality of some 4 percent of anadromous populations forced to migrate around it. If delay and •predation effects were purely additive, then the three other causeways projected could increase the total loss to populations passing all four to as much as 16 percent. However, the validity of these assumptions awaits field testing and monitoring. Presence of additional causeways in the semi-enclosed waters of Simpson Lagoon (e.g., at Gwydr Bay or Milne Point) would perhaps synergistically increase the potential impacts of the existing causeway and its proposed extension on the lagoonal ecosystem. This would occur if both struc- tures caused additive changes in the water quality or circulation pattern of the same portion of the lagoon such that the survival rate of some species through a critical 1 ife history stage was significantly reduced. Oil spills could further reduce populations. Because currents in the Beaufort Sea follow a generally clockwise gyre, oil spills resulting from accidents in the Canadian Beaufort might affect the coastal area of the U.S. Beaufort and further stress fish resources. Marine mammals may be affected by petroleum development in the Beaufort Sea primarily through potential oil spills, noise, and disturbance effects. Bowhead whales will be affected primarily in deeper waters (greater than at least 3.7 m, 12 ft) where their primary migrations occur. Since most waterflood activities would be concentrated onshore of this depth and since bowhead presence in the Prudhoe Bay area is rare and limited to a brief time during the fall migration, this project is not expected to significantly contribute to cumulative impacts on whales. Polar bears are generally thought to be highly sensitive to disturbance by human presence and industrial activity. The area available to bears for undisturbed foraging and denning will be significantly reduced by the projected development along the Beaufort Sea coast (including Canada). Because the proposed Waterflood Project would be almost wholly within areas affected by the existing development, its contribution to cumulative impacts would be slight. Virtually all marine life (including whales) would be affected by a massive oil spill in the Beaufort Sea. However, the maximum spill that could result from the proposed project would be from fuel handling or accidental rupture of a towing vessel fuel tank. Such spills would not be likely to have long-term impacts on large segments of any marine populations. Air and Water Quality Existing environmental protection regulations have been established to prevent significant deterioration of existing air and water quality 4-10 and to· prevent significant· harmful impacts on the natural and human environments. Expanding human population and industrial activity in the Beaufort Sea coastal zone is likely to result in some alterations of the present near pristine quality of air and water. In specific isolated instances (e.g., spill of a toxic substance, heavy construction during a dusty period), local deterioration wi 11 adversely affect natural populations. However, such isolated occurrences will contribute little to large-scale cumulative deterioration and the proposed project would contribute only in direct proportion to the scale of activities prop~sed. ~ ' Discbarge of potentially toxic substances such as the chlo~inated hydrqcarbon react ion products from the proposed water treating p 1 ant will?flikely be required by other developments, including perhaps other wateffloods of other formations. The levels and geographic separation of f.orseeable discharges are such that little cumulative impact is like}ty. Because the Prudhoe Bay waterflood is likely to be the largest waterflood needed in the U.S. Arctic, it would likely contribute a large proportion of the total of water treating discharges anticipated in the Beaufort Sea. Therefore, the overall impact of such discharges, and the contribution of the proposed action to this impact, will be small. I North Slope Sociocultural Effects The dynamics of subsistence species populations, the increased tax revenue, and industry presence in the A_rctic were considered in assessing cultural effects. The total impact of projected development on species important in Inupiat subsistence activities and the antici- pated contribution of the Waterflood Project to such impacts have been· discussed above. Waterflood Project impacts on marine mammals including bowhead whales, seals, and polar bears are considered negligible. Impacts on caribou and birds would be slight and unlikely to significantly affect available subsistence harvests. Impacts to marine and anadromous fish from U.S. and Canadian arctic develo~ment could be important. The Waterflood Project (proposed project with injection volumes expanded by 50 percent) could result in as much as a 2 - 4 percent reduct ion in harvestab 1 e numbers in the Colville and Kaktovik fisheries. Because of the relatively large size of the proposed (and expanded) Prudhoe Bay waterflood intake, these losses would comprise a relatively large percentage of total losses of subsistence fish (at least in the Colville fishery) that might occur due to overall development in the area. Waterflood-related reductions in fish available to the Kaktovik fishery are much more difficult to assess. The proportion of that fishery dependent on fish from rivers west of Prudhoe Bay and hence vulnerable to project impact is unknown. Impacts resulting from oil development in the Canadian Arctic (e.g., Mackenzie Delta) may have a far greater effect on Kaktovik fisheries. 4-11 Reductions of subsistence resources and 1 ittle perceived assurance of either employment opportunity or alternative resources may cause stress within the traditional community. This may result in personal and interpersonal conflicts. However, increased opportunities for the exercise of Inupiat-controlled institutions (!CAS, NSB, local govern- ment) could increase familiarity with and comfort with industry. If successful, vi 11 age and regional corporation businesses may provide a culturally and socially acceptable work mi 1 ieu in which necessary cash can be earned without totally jeopardizing subsistence skills and opportunities. The Inupiat, particularly community leaders, may have an opportunity to work closely with industry in monitoring and learning about the actual impact of either advancing or halting the applicant • s project. That learning process could be of great assistance in dealing with similar circumstances and projects that wi 11 surely occur in the future. It should be noted that few assessment studies are available upon which to base direct project cumulative impacts, yet experience and observation since activities began in 1969 would indicate that much is yet to be learned about the interface of traditional communities, the Inupiat sociocultural context, and industrial activities in the Arctic. Government Policy The existing causeway and the proposed extension, if implemented, are viewed by some as precedent-setting in terms of governmental policy with respect to similar structures that may be proposed in the future. Therefore, implementation of the proposed action would have a cumulative effect on governmental policy. Summary In summary, the primary adverse cumulative effects of the Waterflood Project would be caused by the relatively small direct impact of the proposed facilities added to the considerably greater impacts of exist- ing and planned development within the PBU and the Arctic Ocean. Effects on anadromous fish movement and birds would extend beyond the Prudhoe Bay area and could, under a reasonable worst-case scenario, result in significant reductions in populations available for subsist- ence use and those supporting higher food chain organisms. 4.2 COMPARISON OF IMPACTS This section provides a detailed analysis of the impacts of the proposed action and reasonable alternatives. In Chapter 2.0, these impacts were summarized and discussed in relation to specific components of the project, i.e., all impacts of the low-pressure piping system were discussed in one subsection. In this section, impacts are viewed from the alternate perspective of discussing all project impacts in relation 4-12 . i to each specific environmental component, i.e.; all project impacts on terrestrial ecology are discussed together. Within most sections, impacts associated with alternative construct ion activities and those associated with the presence of constructed facilities are discussed first, followed by impacts of operation of the alternative facilities. LAND USE Prior to the discovery qf oil and gas reserves in the Prudhoe Bay area, traditional land use in\the area was directly linked to the subsistence activities of the Eskim~. Recent changes in the i[nupi at life-style and social organizations have produced changes in lii.f'ld use activities. Subsistence activities now tend. to originate primarily from established settlements such as the villages of Nuiqsut and Kaktovik. The development of oil and gas resources in the Prudhoe Bay area also has progressively displaced subsistence activity, such that land use activities in the project area are now devoted primarily to oil product ion and transport at ion facilities. Construction Impacts Alternative A (Proposed by Applicant) Under the proposed action, about 106 ha (263 acres) of onshore land would be required for facilities. With the exception of the road between Pad K (Term Well A) and Pad E, all onshore land requirements would occur adjacent to existing (by 1984) roadways and pipeline corr'idors within the PBU. Overall land use changes would be minor. Offshore facilities would include extension and modification of the existing causeway, along with development of a seawater treating plant and attendant facilities. To the extent that these facilities alter fish migration patterns, •. affect the density of aquatic organisms in Prudhoe Bay area waters (Section 4.2, Marine Biology), or alter coastal processes (Section 4.2, Physical and Chemical Oceanography), regional land· use activities associated with subsistence resources might be adversely affected and conflicts with the Alaska Coastal Management Plan are possible. Withthe exception of at least one native allotment (located at the base of the West Dock), lands within and adjacent to the Prudhoe Bay area are patented or tentatively approved State lands. Approximately 99,462 ha (245,767 acres) have been leased for oil and gas exploration and development within PBU. The proposed Waterflood Project would have no significant impact on State land ownership. The subsistence use of native allotment lands has already been curtailed by existing development; the Waterflood Project would not significantly add to this impact. 4-13 Current litigation between the State and Federal governments concerning the 3-mi boundary would not be affected by the proposed causeway exten- sion. The State contends that the 3-mi boundary should be measured outward from DH 3. Recent correspondence between •the State of A 1 ask a and the Department of the Interior (Department of Law 1980) states: 11 ••• we [State of Alaska] are willing to litigate the use of the ARCO pier as a salient point for measuring the extent of the grant of submerged lands to the State of Alaska as if no additional construction was taking place ... There are several municipal entitlements pending State approval that are located in the PBU. Since only surface rights to these areas would be conveyed, oil and gas activities could disrupt land use activities planned for these areas, if displacement was required. The proposed Waterflood Project may conflict with several statewide standards (Alaska Coastal Management Program -ACMP) governing major uses or activities in the coastal zone (Table 4.2-1). If permitted, the project could affect the viability of the nominated marine sanctu- aries, although the designation of the area as a sanctuary is considered unlikely even without the proposed project. Several aspects of the project may be inconsistent with Habitat Standard 6AAC 80.130. This standard states that estuaries, barrier islands and 1 a goons, offshore areas, and important upland habitat 11 must be managed so as to maintain or enhance the biological, physical, and chemical characteristics of the habitat which contribute to its capacity to support living resources ... With the causeway extension, natural circula- tion patterns and perhaps nutrient flow would be altered, pot·entially altering productive habitat in Simpson Lagoon. Shaul d the proposed causeway ext ens ion be constructed, it could delay fish migrations and cumulatively might affect coastal subsistence and commercial fishing activities. The proposed intake system and the proposed road from Pad K (Term Well A) to Pad E could also affect subsistence fishing and hunting (see Cumulative Impacts Section, above). The ACMP recognizes that complete nondegradation is an impossible standard to meet, and that certain tradeoffs between natural values and other human values are necessary. As such, uses and activities that may not conform to certain State standards may be allowed if the following are established: 11 (1) there is a significant need for the proposed use or activity; (2) there is no feasible and prudent alternative to meet the public need for the proposed use or activity which would conform to state standards; and (3) all feasible and prudent steps to maximize conformance with the standards contained will be taken ... The ACMP also recognizes the importance of the national interest in Alaska•s coastal zone by including uses and facilities that are of 4-14 TABLE 4.2-1 ACMP CONFORMANCE REVIEW App 1ca le Not Potent 1 a I Standard Applicable Consistent Conflict Remarks 6AAC 80.040 Coastal Development 6AAC 80.050 Geophysical Hazard Areas 6AAC 80.060 Recreation 6AAC 80.070 Energy Facilities 6AAC 80.080 Transportation and Utilities A,B,C 6AAC 80.090 A,B,C Fish and Seafood Processing 6AAC 80.100 A,B,C Timber Harvest and Processing . 6AAC 80.110 A,B,C Mining and Minera~ Processing 6AAC 80.120 Subsistence 6AAC 80.130 Habitats: Estuaries, Wetlands and Tideflats Rock Island and Sea Cliffs, Barrier Islands and Lagoons, Exposed High Energy Coast, River, Streams, and lakes Important Up llnd Habitat 6AAC 80.140 Air, Land, Water Quality 6AAC 80.150 Historic, Prehistoric, and Archaeological Resources (A) Proposed Alternative (B) Gravel Island Alternative (C) Dredged Channel Alternative A,B,C A,B,C Facility is a water-dependent use. A,B,C Requires consultation with State on site location. A,B,C Facility is water-dependent. B,C A,B,C Subsistence resources may be adversely impacted by causeway extension, intake operation, and road extension to Well Pad E. A Causeway extension would alter natura 1 .circu 1 at ion patterns and coastal processes and could destroy protective habitat including estuaries barrier islands, and lagoons, offshore areas. A,B,C Water quality in Prudhoe Bay area could be adversely impacted. A,B,C All measures necessary to preserve and protect such sites if encoun- tered during construction will be taken by the applicant. 4-15 national significance in its definition of 11 USes of state concern ... Uses of State concern cannot be unreasonably or arbitrarily restricted or excluded from the coastal zone district. Included in this definition are resources and facilities that contribute to meeting national energy needs. The proposed Waterflood Project is specifically mentioned in the NSB•s interim zoning ordinance, and is considered to be in compliance with two exceptions: gravel extraction, and activities and facilities undertaken seaward of DH 3. Gravel extraction, under the proposed alternative, would come primarily from existing on-land sources that would be expanded to provide for project needs. These sites are already in compliance with the interim zoning. However, the proposed causeway extension would intrude on a buffer area and be subject to NSB permits. The proposed new gravel site at the base of the causeway is located in a Conservation District as designated by the NSB•s interim zoning ordinance. Permits obtained under the Interim Zoning Ordinance are assumed to be valid under future regional coastal zone management plans. Alternatives Table 4.2-1 summarizes the consistency of intake treatment plant location Alternatives B (Gravel Island) and C (Dredged Ch.annel) with standards governing coastal zone uses and activities. As noted, the potential for conflict with State standards regarding subsistence, habitats, and water quality is reduced or eliminated depending upon which alternative is selected .. Alternatives B and C would eliminate major potential impacts to the barrier islands, Simpson Lagoon, and to marine ecological systems that are associated with the proposed act ion (Alternative A). It is judged that this would bring offshore portions of the project more into conformance with State standards governing habitats. Potential conflicts under 11 subsistence 11 that are associated with impacts of intake operation and with the route from Pad K to Pad E would remain for both Alternatives A and B. On the other hand, the proposed project could be considered consistent with ACMP if it is determined that no 11 feasible and prudent 11 means exist to accomplish the desired oil recovery. It should be noted that, based on concerns expressed by agencies and the public, the applicant has modified the project proposed in the DEIS to include mitigative measures. Operation Impacts Once in place, operation of the Waterflood Project would tend to facili- tate development west of the Prudhoe Bay area because of increased transportation and logistics efficiency. Also, additional waterflood facilities may be built to take advantage of existing structures. Extraction of gravel at existing mines would occur to meet maintenance requirements relative to roadways, pads, and the causeway. The proposed causeway modifications would meet anticipated future .transportation needs related to ocean cargo and oil development. Some increase in air 4-16 and haul road traffic is expected, but related environmental effects are not considered significant. Operational impacts from the various alternatives considered as part of this project would not differ significantly over those experienced under the proposed action. GEOLOGY AND SOILS The most significant impacts of the proposed project on geology and soils are related to gravel extraction and the reduced possibility of subsidence. Construction Impacts Gravel Sources and Needs Approximately 10 million m3 (13 million yd3) of gravel have been mined for the Prudhoe Bay oil field development through 1977 (Hopkins 1978). The Waterflood Project would require 2.5 mi'llion m3 (3.3 million yd3) of gravel for construction of pads, roads, and causeways. Impacts that would result from gravel extraction depend upon the sites chosen for new borrow sources. The material required for this project is available an~ would be extracted from existing borrow sources. Impacts at these sites are expected to be minimal. Mining of gravel in active river channels could disrupt stream flow and affect the habitat and· 1 ife cycle of anadromous fish. Such practices are discouraged by the ACMP. Use of wetlands and marshes as sites for gravel pits would disrupt many species of migratory birds (Derksen et al. 1977). Large thaw lakes, more than 2m (6.5 ft) deep and located at least 1 km (0.6 mi) inland are potential gravel sources. However, the two 1 akes with in the project area that meet these criteria are presently used as reservoirs and it is unlikely that they would be approved for gravel extract ion. The few deep 1 akes remaining are not large enough to provide gravel in quantities worth developing. Mainland beaches, being thin and narrow, are unattractive as gravel sources. If quarried, acceleration of the already rapid rate of coastal retreat, both at the quarry site and for a considerable distance down-drift, would result. The offshore (barrier) islands contain larger supplies of gravel. If, as postulated, the offshore islands are mostly relict features, representing .the coarse residue from erosion of land masses that have long since disappeared (Hopkins and Hartz 1978), they would never be reconstructed by natural processes. Thus, mining of the offshore islands would cause irreversible environmental changes. Offshore subsea deposits are generally less suitable than on-land areas because of the greater uncertainty regarding potential impacts of extraction. Although the applicant does not intend to use offshore deposits for waterflood construction, there may be some logistical and 4-17 environmental advantages (e.g., 1 ess permanent habitat disrupt ion) to using such areas for causeway extension or gravel island construction as an alternative to opening new upland sites. AEIDC (1980) has summarized the potentiil for extracting gravel from an area north of Stump Island in about 3 - 8 m (9 -25 ft) of water (Figure 3.4-1). Holes left in the seabed by offshore extraction would refill gradually by natural processes. Where subsea permafrost 1 ies close to the surface under such dredged areas some degradation of the permafrost could occur (AEIDC 1980). However, future geological and environmental studies are necessary before this gravel source can be considered in detail. The total gravel quantities required for the Waterflood Project are estimated assuming a nominal 1.5-m (5-ft) thickness for gravel pads and roadways. Some gravel savings and perhaps cost savings could be realized by using insulation to replace a portion of the required gravel (Kalaska 1979). In general, for typical North Slope conditions, 5-8 em (2 - 3 in) of insulation (polystyrene most commonly used) can replace 0.9 m (3 ft) of gravel and still equal the insulating effect of a 1.5-m (5-ft) gravel emplacement (Berget al. 1978, Wellman et al. 1976). The effectiveness of combining gravel and insulation has been the subject of many publications within the last decade. The predominant factor affecting the economic analysis of a combined gravel and insulation emplacement versus a full-depth gravel emplacement is the gravel haul distance. A recent report (Kalaska 1979) analyzed North Slope conditions and concluded that at haul distances exceeding 4.8 km (3 mi), the combined gravel and insulation pad is more economical for drill pads than the all-gravel pad. For road construction, the equal cost breakpoint is at a haul distance of 3.2 km .(2 mi). The analyses results for drill pads and roadways are illustrated graphically on Figures 4 .2-1a, and b.· Suitabi 1 ity of polystyrene insulation/gravel roads for heavy modules (in excess of 2000 tons) is questionable, however. Rehabilitation Measures Historically, gravel sources on the North Slope have been located in river floodplains, river or stream bed oxbows, or in upland areas. Rehabilitation plans for gravel sources depend on site-specific condi- tions of each source. In genera 1, the objectives are to make every feasible and prudent attempt to minimize loss of habitat and subsistence use. Overburden, consisting of silts, clays, silty sands or gravels and tundra, which has been stockpiled around the perimeter of the site, could be used periodically during the life of the site to rehabilitate other disturbed areas in the field, such as abandoned waste disposal sites or abandoned gravel pads. The remaining overburden may be stockpiled or graded and seeded. Properly revegetated overburden piles are expected to provide caribou insect relief habitat and denning areas for burrowing mammals. 4-18 GRAVEL HAUL DISTANCE -KILOMETERS GRAVEL HAUL DISTANCE ~ KILOMETERS 0 • 10 15 20 25 30 0 5 10 15 20 25 30 $600,000 _u ___ ~ 2a· TOP ROAD L 1_ .L;c.t J ~ 372,900 1.600,000 I I' DRILL OR CAMP PAD I I -ALL -GRAvEL vs. INSiJLAnci~iGP.-t.VF.L c::Oi.~iJINA i ioN--91 m X 152m (3oorx5oo l -r-- r--r--·---·-·c.;)sr cu.u"f~~~~oN--·---------t-t-ALL-GRAVEL VS. INSULATION/GRAVEL COMBINATION -r-- 1---1-----1--(THERMALLY EQUIVALENT J------7 COST COMPARISON T~r·· ---·- I 1---LLj-i-----; { THER!v1ALLY EQUIVALENT) £500,000 1.5m(5 ')THICK GRAVF,l:-. 310,750 >500,000 I I I --t-H--·t; .Lr-- I---I-------1----1---------r--I I I 1.5m(5') THICK GRAVEL--..., y ---. ----v ------ r---7----- ··- $400,000 -!,L ·----248,600 " $'100,000 -I-1----, ___ 1-/ ~---~ -I-----::; w ~MAGNITUDE OF -"":::::: .. J .. " -~ COST REOU~ "' ' ----·j_;:{ 3 ~AGNITUDE OF COST --,._ ;; ) REDUCTION I L --"' / 0 ' ·-u / ----\;; IL --*-rr l .. ~= ~300,000 / v INS~LATION PLUS [--186,450 8 ._ $300,000 I--------;; I--1--.6m 12) GRAVEl 8 INSULATION PLUS / 1---I / v--J.s m 12'1 GRAVEL /..-e.-GRAVEL COSTS INCLUDE: 0 ----" GRAVEL COSTS INCLUDE: Q. ,.£ -;;!!_ EQUAL COSTS r, _ RO'fALTY ~ -. MINING ROYALTY L_ .2:2~!:',t2:~~~~~~~~ 1--- LOADING ====v 4_ EQUAL COST I@ ----MINING 'b200,LOO 1---HAULING 124,300 $?00,000 4.8km (3 Ml) GRAVE -I-LOADING PLACEME HAUL Dl STANCE HAULING FUEL -1--PLACEMENT FOOD/LOOGING FUEL FOOD/LODGING INSULATION COSTS INCLUDE' ~~L~~ION I INSULATION COSTS INCLUDE: $100,000 62,150 INSULATION LAY-DOWN! I $100,0DD HAULING FUEL LAY-DOWN FOOD/LODGING FUEL I FOOD/LODGING I I I I I I I 0 I I I I I 0 I I i I 0 5 10 15 20 0 5 10 15 20 GRAVEL HAUL DISTANCE-MILES GRAVEL HAUL DISTANCE-MILES a. b. ROAD PAD SOURCE: KALASKA 1979 - INSULATION/GRAVEL COST COMPARISON PBU Waterflood Environmental Impact Statement Figure 4.2--1 4-19 Gravel berms or river control dikes may be built around gravel sources located in floodplains. Depending upon site-specific conditions, the dikes would remain in place and be maintained to counteract erosion, scour, and otherwise prevent channelization into the site, which could entrap fish. If the site has not been inundated with water through seepage and snow melt, the bottom would be smoothed to eliminate any deep depressions that could entrap fish or animals. The sides of the site would be sloped (approximately 3:1). Any gravel islands remaining from the mining operations would be left to provide nesting habitat. Earthwork The onshore impacts of construction activities such as ditching, cutting, and pad and road placement include flow blockage (both surface water and shallow ground water) and thermal disturbance. The two are interrelated since flow blockage can cause or contribute to thermal disturbance. Flow blockage caused by pad and road construction would alter surface water drainage patterns. Because of the relatively flat terrain in the project area, the magnitude and rate of surface water flows are small and blockage impacts should be minor. Also, because of this flat terrain, culvert placement has not been satisfactory in many cases. Culverts should be provided wherever necessary and feasible to maintain existing flow patterns. The thermal balance of the frozen soil regime in the project area is delicate and significantly affected by what would elsewhere be considered minor disturbances. Activities that remove the natural insulation provided by the tundra mat are normally the most detrimental. The ensuing degradation can result in thermokarst development, thaw settlement, and thaw lake formation. Construction activities that compress the tundra mat can result in similar disturbances. Project plans are cognizant of the delicate nature of the permafrost soils in the project area. Pipelines would be elevated and roadways constructed as overlays. Roads and pads would have sufficient gravel to recreate the insulating effect of the compressed underlying mat. Onshore construction would be largely confined to the existing Prudhoe Bay industrial enclave; it would extend existing roadways and add new, but similar, pads. Offshore earthwork activities should have very little impact on soils and geology. Operational Impacts Ponding and Blockage of Shallow Groundwater Flow Recent studies (Davidson in press) of the Prudhoe Bay area indicate that efforts to prevent permafrost degradation under pads, airfields, and 4-20 roadways have caused permafrost to aggrade into the gravel emplacements. The rise in the permafrost blocks groundwater flow and percolation in the active layer. This blockage results in ponding of water adjacent to the gravel facilities. Both high and low-centered polygons are affected by the ponding (Davidson in press). The ponding gradually increases the depth of summer thaw in a given area and causes subsidence as ice-rich soils thaw. As more area is flooded by subsidence, the ponded area approaches the size and depth of a thaw lake. Formation of thaw lakes adjacent to gravel emplacements could result in thaw bulb progression into and under the pad or roadway and loss of load-carrying capacity in the underlying soils. I Heave and Settlement :r Sfi~ce fine-grained and high-ice-content permafrost soils are common to tlie project area, the maintenance of thermal balance is important. Sufficient gravel placement is necessary to insulate permafrost soils against thaw and prevent settlement beneath pads and roadways during operations. However, excess gravel will cause the permafrost to aggrade into the active layer. Where the active layer is of nominal thickness, heave would be insignificant; where localized deeper active layers are present, significant and possibly differential heaving may occur. Aggrading Offshore Permafrost Widening and extending the existing causeway could cause some aggrading of subsea permafrost. However, the amount of gravel necessary to counter ice loading, wave action, and currents should provide sufficient overburden to prevent heave as permafrost aggrades upward. Sol ids accumulated on the seabed during periods of under-ice discharge should not affect subsea permafrost because of its depth beneath the seabed and because the accumulations would not contact the air or the under-ice surface. Subsidence from Oil Withdrawal One 'notable example of ground subsidence in conjunction with substantial withdrawals from subsurface rock format ions of oil, gas, and water is the Long Beach, California, harbor area. Development of the Wilmington Oil Field located in this area began in 1938, and by 1945 one area had sunk as much as 1.2 m ( 4 ft). The consensus of authorities was that the :withdrawal of fluids from the oil zones and consequent loss of underground pressure support enabled the weight of the earth above to exert a 1 arge downward force and compact the oi 1 zones. The surface then sank in response to this effect. The most practical means of combating subsidence appeared to be the injection of water under pressure into the oil zones. This also, of course, could provide a substantial quantity of additional oil production. By 1952, when water injection commenced, the area located over the center of the field was sinking at a rate of more than 0.6 m/yr (2 ft/yr). Eventually, a subsidence depth of over 9 m (29 ft) was reached until about 1960 when 4-21 the results of water injection began to be effective. By 1966 the entire area had stabilized and certain areas actually regained some of the lost elevation (City of Long Beach 1969). It appears unlikely that subsidence would occur at the Prudhoe field (Wandzel 1980) as the producing zone is considerably deeper than that in the Long Beach area (about 2743 m versus about 914 m, or 9000 ft versus 3000 ft); further, the Sadlerochit Formation is consolidated sandstone. The likelihood of subsidence is deemed remote, more so if waterflood takes place, since historically deep subsidence has occurred because of fluid withdrawal, not injection. No government or industry monitoring program for regional subsidence is known to exist. Seismological Activity There has been some evidence published that a relationship exists between water injection activity and earthquakes in the immediate vicinity (Hall ister and Weimer 1968). It appears that an area with a high frequency of earthquake activity could present a situation that could be aggravated by water injection in close proximity to fault planes. Prudhoe Bay is not such an area; it is generally considered one of low seismic risk, with a relative seismicity factor of 1 (effective ground acceleration of 0.05 g). VEGETATION AND TERRESTRIAL WILDLIFE Construction Impacts Alternative A (Proposed by Applicant) Approximately 106.2 ha (262.5 acres) of previously undisturbed terrain would be covered with gravel and, therefore, lost to biological produc- tion (Table 4.2-2). All but 17.3 ha (42.9 acres) of this total is immediately adjacent to areas of existing construction and disturbance. Extracting 2.7 million m3 (3.3 million yd3) of gravel from existing material sites would require site expansion and, consequently, addi- tional terrain disturbance. Total projected gravel needs for all development activities between the Putuligayuk and Sagavanirktok Rivers for the next 5 years have been estimated at 10.7 million m3 (14 million yd3) (Alaska Department of Natural Resources 1979a); therefore, water- flood requirements would contribute about 25 percent of the total cumulative impact of gravel removal in the area. The Putuligayuk Oxbows and Kuparuk Dead Arm sites (Figure 3.4-1) could be expanded approximately 16 ha (40 acres) and mined to a depth of 15 -21 m (50 -70 ft). Since gravel mining at these sites involves stripping approximately 1.5 - 5 m (5 -15 ft) of organic overburden and excavating a deep pit, it is unlikely that this disturbed area would ever return to its original condition. Whether or not the disturbed area returns to a biologically productive state would depend on restoration measures • 4-22 TABLE 4.2-2 DIRECT TERRESTRIAL HABITAT LOSS DUE TO PAD EXPANSION 0~ CONSTRUCTION Location (Type) Well Pad K (Term WeltA) to Pad E (road) Module Staging Area ~p CCP (new work padl! ::) W~ll Pad C to WF 1 (dpgrade work pad to road) U: Well Pad WF 1 (new pad with access) Injection Plants (2) Intermediate Manifolds (4) Drill Pad Modifications (27) Gravel Sites (expansion) TOTAL Dimensions 3.4 km x 18 m (2.1 mi x 59 ft) 7.2 km x 12.8 m (4.5 mi x 42 ft) 4 km x 5.5 m (2.5 mi x 18ft) 300 m x 100 m (984 ft X 328 ft) 4-23 Area Covered 6.1 ha (15.1 acres) 9.5 ha (23.5 acres) 2.2 ha (5.4 acres) 11.2 ha {27.7 acres) 5.2 ha (12 .8 acres) 1.8 ha (4.5 acres) 45.0 ha ( 111.2 acres) 25.2 ha (62.3 acres) 106.2 ha (262.5 acres) (see Geology and Soils). The Sagavanirktok River (Sag C) site would involve shallow excavation and less overburden; therefore, restoration would probably be more satisfactory. Waterflood project facilities would not affect the known location of the plant species, Thlaspi arcticum (Murray 1980b), which has been proposed for protective classificat1on. It is possible that some project sites on similar habitat (river terrace alluvium) could interfere with currently unknown areas of Thlaspi concentration, especially drill pads M, S, and R, the Kuparuk crossing, and the Kuparuk gravel site. A habitat evaluation procedure utilizing the criteria developed for the five thematic maps in Appendix L has been applied to 1 andscape areas that would be altered directly by waterflood facilities (Table 4.2-3). As reflected in Table 4.2-3, waterflood project facilities have been sited to avoid the higher quality habitats in most cases. Changes in drainage patterns resulting from gravel fill during pad and road construction would alter soil moisture and, consequently, alter the nature of vegetation within limited areas. Ponding adjacent to fill areas would kill existing vegetation (Walker et al. in press). If ponding continues, a change in vegetative species composition from mesic to more aquatic types may occur. An extended period of time, however, may be required before water-tolerant species invade artificially ponded areas (Rothe 1980). Blocking downstream flow may cause subtle changes in wetland vegetation and disturb plant succession. Arctophyla, a component of high quality waterfowl habitat, is characteristic of later successional stages and stable surface water conditions. Destruction of this vegetation would be essentially irreversible. Adequate provisions for cross drain age could accompany road and pipeline pad construction to minimize ponding and related effects. Such provisions would normally include adequately sized culverts placed at or below normal ground level. De-icing equipment would be employed as necessary to prevent culvert blockage. However, experience to date indicates difficulties in achieving adequate drainage in some instances. Therefore, some adverse effect related to blocked drainage is predicted. Studies at Prudhoe Bay indicate that gravel road construction may spread dust tens or hundreds of meters from a 11 roads (Connors 1979) . Dust generated from pad construction and associated road travel would affect nearly all vegetation. On the lee side of a road, a heavy concentration of dust can reduce photosynthesis by restricting light and can block stomata. This would in turn decrease primary productivity and could eliminate certain species. Mosses and 1 ichens are particularly sensitive to heavy dust pollution (Walker et al. in press). A rough calculation of the area that could be impacted significantly from increased dust would include 68 ha (168 acres) adjacent to new roads (assumes impacts within 100 km, 328ft, of roadways). Additional • 4-24 ~ I N U1 TABLE 4.2-3 RELATIVE HABITAT VALUE AND/OR SENSITIVITY OF TERRAIN DIRECTLY ALTERED BY WATERFLOOD PROJECT FACILITIEs(a) Habitat Value or Sensitivity Rating Moderate Evaluation Category High (High Moderate) : (Low Moderate) -~:.· ... I Primary Productivity(b) . 40.1(c) (30.5%)(d) 31.1 (23.7%) Saltwater Sensitivity(b) I 1.2 ( 1.0%) 11.9 ( 9 .1%) : 55.2 (42.0%) Bird Habitat Value 5.5 (4.2%) 3.7 ( 2 . 8% ) : 48 . 9 (37.3%) I Mammal Habitat Value 1.3 ( 1.0%) 30.3 (23.0%) Overall Habitat Value/ I . --·., ·--·-···'~··,·'"-·"•.•· . .. :: ....... · ....... ~ ... -·.·-······= .•. ·: · .. I Sensitivity 5.8 (4.4%) 3.6 (2.7%): 43.6 (33.2%) Total Area Affected -------- Low - 35.1 (26.7%) 51.2 (40.0%) 73.1 (55.7%) 100.2 (76.0%) -··- 78.3 (57.6%) 131.3 (a)figures are based on ground-truthed maps provided in Appendix L. The discrepancy between this table and Table 4.2-2 in regard to the total area affected is due to the following: The Appendix L analysis included as affected area the existing road segment from West Dock to Well Pad K and the previously disturbed portions of the Putuligayuk River gravel sites whereas Table 4.2-2 does not. Also, the East Injection Plant was omitted from the Appendix L analysis. (b)Analysis of these categories did not include open-water habitats; therefore, percentages add up to less than 100 (open water accounts for about 8.4 percent of total). (c)Affected area in hectares. (d)percentage of total impacted area. Percentages do not necessarily add up to exactly 100 because of rounding errors. '~ dust impact would occur adjacent to existing roads as a result of construction traffic. Various dust control measures would be used during construction to minimize the problem. These habitat losses and alterations would have minor effects on mammal populations, as indicated in Table 4.2-3. However, cumulative effects may be more significant. Waterbirds use most coastal plain areas at some time during the thawed season; therefore, some bird habitat would be destroyed. The total area of wetland habitats lost would be 60.1 ha (149 acres) (Appendix L), most of which is moderate quality sedge-meadow bird habitat. This habitat is used primarily by shorebirds for nesting and feeding. Using the figures from Appendix L, Table L-9, it might be expected that about 90 breeding pairs of shorebirds would be directly displaced by waterflood develop- ment along with smaller numbers of waterfowl. The proposed road between Pad K (Term Well A) and Pad E to the west side of the field would cross a drained-1 ake basin complex and, consequently, would impact higher quality bird habitat and disrupt a valuable habitat unit. Alternative alignment A-3 avoids the more sensitive elements of this complex, is located in a more upstream position of the watershed (therefore reducing the risk of damage from blocked drainage), and reduces the habitat fragmentation effect of a more westerly route. Caribou and waterfowl would be particularly affected by noise and other disturbances created during construction. The most serious effects are likely to occur near the road to the west side of the field where the current disturbance level is relatively low. Existing development has caused the cow/calf segment of the Central Arctic caribou herd to generally avoid Prudhoe Bay (Cameron et al. 1979). Waterflood activities would increase cumulative disturbance impacts on caribou and extend the impact zone north of Well Pad E. Disturbance to waterbirds is likely if construction takes place from May 15 to October 1, especially if it occurs within 1 km (0.6 mi) of valuable wetland types (as shown in Appendix L and described in Bergman et al. 1977). The road from Well Pad E to Pad K (Term Well A) would bisect an area of high quality habitat and construction disturbance could be severe depending on the time of year. Longshore migration of waterfowl could be disrupted to a minor degree by construction activities along the causeway and offshore (e.g., dredging for discharge pipelines). Some animal nuisance problems may be created, especially if food is made available to animals. Arctic foxes are likely to become dependent on artificial food sources resulting in potential harm due to modified behavior and population imbalance. Safety hazards to human beings may result because of the likelihood of rabid animals. The increased zone of disturbance adjacent to the coast may reduce potential denning habitat for arctic fox and polar bear. It is unlikely that impacts caused specifically by the Waterflood Project would be significant relative to local populations of these animals. However, 4-26 the cumulative impact of oil development, both existing and planned, for the area between the Colville and Canning Rivers would reduce the options available to arctic fox and polar bear and may cause long-term impacts. Alternative Designs and Configurations Most of the design alternatives discussed for the Waterflood Project waul d not affect construct ion impacts on the terrestrial b io 1 ogica 1 environment. However, alternative configurations of onshore facilities, particularly pipeline routes, may alter potential impacts.: ' The proposed alternative calls for low-pressure pipeline~ to the east and west sides of the field to follow different routes soutih of the West Dock. Two alternative routings for the west side routei.\ between Well Pads K and E waul d reduce somewhat the disrupt ion of a iarge drained- lake complex in this area (Figure 2.5-~3) but would havei~reater areas of direct habitat loss (Table 2.5-8). A final alternative configuration would be for both pipelines to follow the existing road from the West Dock to the CCP, then follow existing pipelines to the east and west injection plants. This routing would eliminate the western pipeline leg. Direct terrain disturbance (6.1 ha, 15.1 acres), dust, and noise would be eliminated from this area. Total gravel requirements would be reduced by about 122,000 m3 (160,000 yd3). It should be noted that multiple use of the road/pipeline route is anticipated and, thus, expansion of the Alternative B route is expected. Conventional road and work pad construct ion in the Prudhoe Bay area employs a thick gravel pad to prevent melting and degradation of frozen soils beneath the pad surface. An alt~rnat ive construct io·n method that employs rigid insulation covered by a thin layer of gravel would require much less gravel, thus alleviating terrain disturbance from gravel mining. The roads and pads would also present a lower profile and less of a barrier to caribou movements. Residues remaining at Prudhoe Bay following abandonment could have a long-term aesthetic impact. There is a risk that the rigid insulation would not withstand the stresses of modular traffic that would likely be routed over the new road to the west side of the field. If the insulation were damaged, the negative impact on permafrost could be severe. Alternative pipeline construction modes include suspension above a gravel berm or burial within a gravel berm. Both modes would require 1 arger quantities of gravel than the proposed pile-supported mode and would create proportionately greater i'inpacts due to gravel mining and construction noise. The proposed alternative would use gravel from two existing pits along the Putul igayuk River with some additional material coming from the existing Kuparuk and Sagavanirktok 11 C11 sites. A possible alternative would develop new upland material sites, involving greater terrain disturbance than expansion of an old site. One gravel site 4-27 under consideration is near the coast, southwest of the base of the West Dock. Impacts, particularly in relation to waterfowl, would be significant at this salt marsh site. This type of habitat was rated as valuable to waterfowl (Bergman et al. 1977) and is utilized particularly by geese. Operation Impacts Alternative A (Proposed by Applicant) The 106 ha (263 acres) of habitat used for pad and road construction would be removed from production for the life of the project and for many years to follow. Subtle changes in local drainage patterns resulting from gravel fill may cause progressive long-term changes in the composition of vegetation within limited areas adjacent to, and downstream from, the fill. Operation of waterflood facilities would add to the cumulative dust fallout adjacent to roadways within the Prudhoe Bay development area. Indirect impacts on the vegetative composition in areas of acid soil may result from progressive reductions in soil acidity caused by the addition of nutritive ions (especially calcium) that, in time, could neutralize the soil (Everett 1979). This could eliminate many moss species, especially the acidophilic varieties such as Sphagnum, and allow an increase in sedges and woody plants. If other spec1es did not increase in abundance and maintain the insulating blanket, the permafrost might be modified. Some long-term decrease in regional primary productivity would result from the loss or alteration of vegetative communities. Productivity at the community level within the Waterflood Project area is analyzed in Appendix L. Since construction would be generally in the drier, less productive areas (Table 4.2-3) and the total amount of tundra removed from productivity would be small (106 ha) relative to the total area of the Arctic Coastal Plain, it is unlikely that this loss would have a significant impact on total ecosystem productivity. One aspect of habitat sensitivity that is especially applicable to an analysis of impacts from the Waterflood Project is the sensitivity of flora to saltwater. If a leak or break should occur in either the low or high-pressure pipelines, a substantial saltwater spill would result. Volumes of up to 16,500 m3 (4 million gal) of heated (4.4°C, 40°F) saltwater could be spilled from low-pressure pipelines if the break occurred near the module staging area. Up to 1400 m3 (370,000 gal) (27°C, 80°F) could be lost from the high-pressure pipelines. Although the likelihood of such ruptures cannot be quantified, a worst- case scenario of one low-pressure pipeline rupture has been assumed over the life of the project. Saltwater from a rupture at the module staging area or along the eastern pipeline corridor (maximum potential volume) could be easily channeled to the coast. From an ecological standpoint, 4-28 a rupture in the western pipeline between Well Pad E and Pad K (Term Well A) would constitute a worst case spill. A potential volume of 5000 m3 (1 million gal) would spread out over 50 ha (125 acres) of tundra, assuming a uniform 1 em (0.4 in) depth.· Containment in this area would be difficult and saltwater would likely become entrained in the extensive water drainages flowing northward. It is also reasonable to assume a worst-case scenario of one high- pressure pipeline rupture (1400 m3 maximum volume) over the lifetime of the project. Assuming an average 2-cm (0.8-in) spill thickness, brine could spread out over 7 ha (17.3 acres) of tundra. An uncontained spill could become entrained in nearby wetland drainages and possibly spread over an even more extensive area. The greatest environmental impact probably would result from a break in the portion of the high- pressure pipeline between Pad E and the west injection plant since brines could become entrained in the northwest drainag~s and spread through these relatively undisturbed wetlands. · No definitive studies have been carried out on the tolerance of tundra plants to saltwater spillage. However, the effects of storm surges near the shore of terrestrial communities at Prudhoe Bay give some indication of the relative sensitivities of the various plant forms and sites (Webber and Walker 1980). Based on their observations of vegetation · types typical of the project area, Walker and Webber devised a scale that rates plant communities according to their relative sensitivities to saltwater during the growing season. This scale was used to rate the major vegetational communities of the Prudhoe Bay area from 0 - 3 according to their loss of vigor and their ability to· recover (see Appendix L). Brine sensitivity ratings were mapped for the area in the project area where spills would be most likely to occur,ji.e., the east and west pipeline corridors. Pipeline manifold and drill~pad areas were not mapped for brine sensitivity, since these facilities have emergency dump areas and the risk of any uncontrolled spillage is extremely low. Dry sites are considered to be generally more sensitive to saltwater than wet sites, with moist sites having an intermediate sensitivity (Walker 1980). This is based on the premise that moist :and wet sites would be subject to natural flushing by fresh water and that graminoids, which are prevalent on moist and wet sites, are more tolerant to saline conditions than forbs or dwarf shrubs, which are more abundant on dry sites. Some vegetation communities, for example intertidal wet meadow and coastal barrens, would be preadapted to or naturally tolerant to inundation from brine. These communities are not extensive within the region as a whole but are relatively important along'the corridor routes, particularly the east corridor. The extent of any impact on existing vegetation would vary with the time of year. A spill during winter, when plants are dormant, would cause relatively little or no damage. A leak or small volume spill at this time would 1 ikely freeze before penetrating below the snow and could be cleaned up before the spring melt. A larger volume spill would 4-29 ,. j. \·' ~ ~- penetrate to or slightly below the ground surface and could affect plants during the next growing season. This impact would be alleviated by spring runoff, which would cause a flushing of the system. A spill during the 1 atter part of the growing season would probably have the greatest effect since the dilution factor would be lowest and plants would be actively metabolizing. Progressive 1 ong-term changes in vegetation compos it ion from any of the above causes may· be detrimental to waterbirds. Dust effects may also impact birds directly. Studies by Connors and Risebrough (1979) indicated that densities of breeding shorebirds were significantly lower in dust shadow areas than in the adjoining tundrp.. Dust generated in spring darkens the snow and causes it to melt more quickly adjacent to oil field facilities than in other areas. Migratory birds are attracted to these early open-water areas and become concentrated with in the oi 1 field (Klein and Hemming 1976). The birds may receive some benefit from this phenomenon but, on the other hand, become more vulnerable to man-created hazards such as oil spills. Noise created by mechanical facilities and vehicle traffic during waterflood operation would add to the cumulative disturbance of area animals. Highest noise levels would be associated with injection plants; however, these facilities would be adjacent to existing mechanical plants and additional impact would probably be minor. Of greater importance to animals would be new activity associated with the road and pipeline from the dock to the west injection plant. Based on previous studies (Cameron et al. 1979), it appears 1 ikely that caribou habitat would be effectively reduced, at least as far as the cow/calf segment is concerned. Waterbirds would also be disturbed with impact severity depending on the level of noise and time of year. The density of nesting birds adjacent to roadways and other facilities probably would be reduced (Connors and Risebrough 1979). The west road would cross high quality wetlands, thereby increasing the likelihood of adverse impacts on waterfowl. The elevated powerl ine from the CCP to the base of the causeway may cause some bird mortality. Free movement of caribou could be hampered by the two proposed low- pressure pipelines from the module staging area to the east and west sides of the field. Both the east and west pipelines would traverse about 9.6 km (6 mi) of terrain where no pipeline now exists (southward from the coast). Caribou are known to react to artificial structures and, although some animals will cross under elevated pipelines, others may not (Child 1973, Cameron 1980). The presence of the pipe structure, along with disturbance due to noise and activity, would further reduce existing minimal caribou use of the region east of Pad K (Term Well A) and Well Pad E. Impacts on regional or worldwide wildlife populations would be insig- nificant from the Waterflood Project alone. However, the cumulative effects of oil development to date, plus that anticipated for the future between the Colville and Canning Rivers, will reduce the options 4-30 available to mobile species such as caribou and waterfowl. These reductions in range or useable habitat could cause long-term population reduction with potential implications relative to subsistence and recreational use of international resources. Alternative Designs and Configurations The alternate route of the west low-pressure pipeline along the existing road to the West Dock would minimize disturbance to birds and caribou in the sensitive area south and west of the dock and would eliminate potential blockage of caribou movements in the same area. Whether or not this alternative would significantly reduce long-term impacts would depend on development plans for the field as a whole. If the area between the West Dock and Well Pad E is planned as a transport at ion corridor regardless of the existence of waterflood facilities, the elimination of one pipeline would not significantly reduce impacts. Alternative modes of pipeline construction would also alter impacts during operation. Pipe on top of a gravel berm would create a greater block to caribou passage than would an elevated pipe because of the visual and physical barrier (Cameron 1980). Pipe buried within a gravel berm might improve caribou passage providing the berm is not so high that a complete visual barrier results (Hanson unpublished data). Cross drainage is more difficult to control with a gravel berm. A greater area of tundra would be covered, more gravel would be required, and greater impacts to adjacent terrain would result. An elevated power line running along the causeway could be considered as an alternative to buried cables. Some mortality to birds would be expected as a result of collisions with the wires especially since the 1 ines would transect a natural east-west migration pathway along the coast. Additionally,. the causeway is adjacent to waterbird concen- tration areas that are often subjected to fog and low ceiling weather conditions and represent a break in the otherwise flat seascape. The above conditions suggest an unusually high potential for bird-power line collisions (U.S. Fish and Wildlife Service 1978). However, the number of birds killed is likely to be small in relation to total area populations. Local incidents during unusual weather conditions have resulted in instances of high morta1ity. WETLANDS Construction and Operation Impacts Alternative A (Proposed by Applicant) Of the total area that would be directly altered by gravel fill, 60.1 ha (149 acres) or 46.1 percent is classified as wetland according to the criteria presented in Appendix Land 11 ha (27.3 acres) is classified as open water. In addition, wetland structure and function would be 4-31 altered by blockage of natural drainage patterns, dust shadow, and disturbance of wetland inhabitants. General wetland-related impacts on vegetation and wildlife are discussed in Section 4.2, Vegetation and Terrestrial Wildlife. The following paragraphs address wetland impacts in relation to the special values and criteria presented in Section 3.7. Some plant and animal productivity would be lost. An analysis of the waterflood site locations, as outlined on the overall habitat value maps in Appendix L, indicates that the specific wetland areas directly altered by waterflood facilities tend to be of the less productive Prudhoe Bay wetland types. Site planning avoided the higher quality Sohio Alaska Petroleum Co. The open water and wet tundra near Well Pad D (foreground) is typical of sensitive environments at Prudhoe Bay and illustrates the need for interdisciplinary planning. areas in most cases. Furthermore, the area involved is relatively small. Therefore, these losses in production resulting from wetland fill would probably not be significant on a regional basis. Of perhaps greater importance would be modifications in wetland characteristics downstream from a point of blockage. Such changes could affect a large 4-32 area, especially if interconnecting wetlands are involved. The rich populations of invertebrates upon which waterfowl feed, as described by Bergman et al. (1977), are associated with specific vegetation types that could be destroyed if water levels are lowered. Upstream from flow blockages, flooding is possible. Because areas susceptible to flooding are in low areas, wetlands with high habitat value could be adversely affected. Disturbance of consumers, especially waterbirds, would also interrupt the food web. In this case the wet 1 and proper may not be affected but its energy waul d not be fully uti 1 i zed or transferred to other systems. Animal use of wetlands would be reduced somewhat through direct habitat loss and through disturbance from noise and activity. Disturbance impacts probably would be more significant in regard to birds and mammals than would direct habitat loss (Section 4.2, Vegetation and Terrestrial Wildlife), since a potentially larger area would be affected. New facilities would be sited to m1n1m1ze interference with drainage patterns. Nevertheless, experience with existing facilities suggests that some interruption of these patterns would occur, especially where new roads and pipeline workpads are required. The new road and pipeline corridor from Pad K (Term Well A) to Pad E would cross a drained-lake basin wetland complex and could have a significant impact on the local surface water regime. Other waterflood fac i 1 it ies waul d, for the most part, affect only isolated wetlands and significant hydrological impacts would not be expected. · Flow of nutrients and energy originating in wetland areas could also be affected by alterations in drainage patterns. Productivity of downstream areas could be reduced if nutrient flow were blocked. Such effects would be most likely to occur where new roads or pipelines cross existing drainage ways or wetland complexes as discussed in the above paragraph. Regional impacts on the nutrient flow regime would be unlikely from waterflood facilities alone. However, cumulative impacts from present and future deve 1 opment caul d reduce the net amount of nutrients reaching areas downstream from the development sites. Such an effect could ultimately impact the nearshore marine environment. Effects of dust on productivity and plant species have been discussed under construction and operation impacts. Besides a change in wetland acidity, dust may cause nutrient enrichment of flooded areas and pond or lake communities near roadways, and stimulate algal production (Alexander and Miller 1977). Wet sites are considered to be less sensitive to brine spills than dry sites because of the greater dilution factor (Walker 1980). Impacts of a saltwater spill on vegetation are discussed in detail in Section 4.2, Vegetation and Terrestrial Wildlife. 4-33 Major disruptions of high quality wetland habitats probably would not occur as a result of the Waterflood Project. Therefore, significant impacts on recreational uses, such as wildlife observation, would be unlikely. Access to wetland areas would probably be improved. Overall degradation in wilderness and aesthetic quality would result from the cumulative effects of past and future development. Other Alternatives The relative construction impacts of the other alternatives in relation to the proposed alternative on wetland areas have been discussed in Section 4.2, Vegetation and Terrestrial Wildlife. Alternatives that would minimize new terrain disturbance, such as consolidating the east and west low-pressure pipelines along the eastern route, would alleviate wetland impacts. Alternative road alignments (Figure 2.5-23) also would reduce the ecological effects of wetland losses and habitat fragmentation. Disturbance to birds would still exist, however. PHYSICAL AND CHEMICAL OCEANOGRAPHY Physical characteristics of the marine habitats in the Prudhoe Bay vicinity that might be affected by the proposed project include near- shore processes, circulation, water quality, and sea ice. Nearshore processes, especially sediment transport, are greatly affected by jetties, causeways, and other structures that alter nearshore circu- lation. Water quality is affected by the locations of and interactions among water masses, which may be affected in turn by nearshore struc- tures. The significance of the ice processes depends on their importance in creating and maintaining critical aspects of the marine environment. To assist in evaluation of physical, chemical, and biological impacts of the proposed action, an unverified two-dimensional model was used to predict circulation and salinity for the proposed and alternative configurations (Dames & Moore 1980b, Appendix D). Model results must be interpreted with caution but are considered indicative of relative differences between alternatives. Construction Impacts Potential adverse impacts on the physical and chemical marine environ- ment that would result from each of three major intake configurations and design alternatives are described be 1 ow. These a 1 tern at ives are: the proposed configuration, with the seawater treating plant and intake at the end of an extended causeway; placement of these structures on a gravel island; and placement of the treating plant and intake at DH 3 with a dredged communication channel to the 3.7-m (12-ft) contour. 4-34 Alternative A (Proposed by Applicant) The major potential effects of construction of the causeway extension and seawater treating plant would include: Transport and deposition of fine-grained sediments resuspended by dredging or washed from gravel fill. Temporary reduction in light penetration in the water column during dredging. Possible temporary reduction in dissolved oxygen during dredging. Altered currents in the vicinity of the causeway. Intermittent local changes in salinity of approximately 3 - 4 ppt. Changes in shoreline configuration, particularly west of the causeway and a potential for narrowing of the gap between Stump Island and the proposed causeway. Establishment of a situat.ion where ice conditions (override or ride-up, gouging or scoring, push) could affect project structures. Possible changes in local ice processes and the ice regime. Suspension of sediments in the water column would occur during construc- tion primarily from dredging and spoil disposal, and secondarily from fill placement and from prop wash and wakes of tugs and barges working in the area. Chemical and physical impacts of suspended sediment can be classified as either short-term or long-term. A short-term physical impact is the creation of turbidity clouds. The sediments of the area are predominantly fine grained; 85 percent of the sediment sampled over 2 years ranged in size from fine silt to fine sand (Woodward-Clyde Consultants 1979). Fine silt and silt, comprising 37 percent of the sediment, would settle slowly after resuspension, as would any clays present. Adverse impacts associated with turbidity clouds would be: a reduction in light penetration (lower transmissivity) that affects organisms dependent upon photosynthesis; flocculation of planktonic algae; a decrease in food availability; and a decrease in aesthetic value. Such impacts would be relatively minor in the usually turbid project area and would dissipate rapidly once dredging and other activities resuspending sediments have ceased. Short and long-term chemical impacts could arise from the alteration of the sediment-water interface .with the subsequent release of bio- stimulatory or noxious chemicals. The resuspension of detritus, with 4-35 subsequent decomposition of organic matter could lower dissolved oxygen concentrations locally. Dissolved oxygen levels also could be lowered by the release of reduced compounds, such as sulfides and methane. Additionally, dissolved oxygen concentrations can be affected adversely by high suspended sol ids concentrations that effectively reduce atmo- spheric reaeration and oxygen transfer. All of these unfavorable impacts on dissolved oxygen concentrations would be localized, short- term, and would disappear once the resuspended sediments have settled or have been sufficiently dispersed so that reaerat ion bal-ances oxygen uptake. Re-entry of nutrients (phosphates and nitr~tes) could briefly stimulate algal growth, a short-term chemical impact. However, the relatively low phosphate concentrations in the sediments indicate such growth would be minimal. No adverse impacts to water quality would be expected from the resuspension of pesticides, trace metals, or PCB's. Elutriate data (Table C-1) indicate these noxious materials are undetectable or in low concentration (Peterson 1980). Changes in circulation patterns would result from the proposed causeway extension. Two-dimensional hydrodynamic and water quality modeling (unverified) has been conducted to estimate these circulation changes and the resultant effect on the salinity distribution during the open-water period. Complete results of this study are presented in Appendix D. Figure 4.2-2 compares model predictions (with and without the proposed extension) for typical summer wind conditions (10 knots from ENE) and low river discharge (common in July and August). Circu- 1 at ion changes are generally confined to a small area within 1 - 2 km (0.6 -1.2 mi) upwind and downwind of the causeway extension. Perhaps more important than these changes in circulation are the resultant changes in water quality. Modeling was conducted using salinity distributions as an indicator of water quality. Figure 4.2-3 shows the predicted salinity changes that would occur from the extended causeway. East winds result in salinity decreases of up to 4 ppt north of the causeway extension and increases of 2 - 4 ppt up to 8 km (5 mi) downwind in eastern Simpson Lagoon. This would be true under both high and low river discharge conditions (see Appendix D). Under high river discharge conditions, west winds waul d reduce ambient salinity in a small area west of the extended causeway by as much as 6 ppt below levels expected to occur in the absence of the extension (see Figure D-25). However, the low river discharge condition is likely to be more typical. since high river discharge usually occurs before the break up of nearshore ice and hence before these circulation patterns are established. West winds result in salinity decreases up to 3 ppt just west of the causeway extension under low river discharge conditions. Elsewhere, changes are generally less than 2 ppt. Changes in circu- lation and water quality for the under-ice condition were not modeled due to limited understanding of the forces driving under-ice currents. It is probable that no significant changes would occur from the proposed alternative since the existing under-ice currents are extremely weak and variable. 4-36 / / / I I I I / / / / / / / / / / / / I I I I / / / / / / / / / / / b/ -I --I / 0 0 / / b/ . I --I / --------------------~~------------------ --------------~~------,-~---------- ===== --------------------------.......... -------------------------;_------------ =======~-:---------------------......... ---------------------------------------------------------::::::;;;;;;;:--------------------....... ----,,, ____________________ ~_ /---~ ,,,s~~~---~-----~------~ { ;=:=:~:~~~=~~~~::====~~~~--1 ., __ / ____ , ____ •-• I,,,,,,,, ______ _..,/ /,/,, ________ ,,,. '· ·'~~~~~un~--/ / ----------------~-· .. ,.,~~~Q~~----/ .......... __ /_ .......... __ , ___ /~_,,_~~' ,,,,, _______ / / / --//1' ,, ___ ,, ., .... _ _,,,. ,, .... ,,, ___ ////// I • 1,, __ ,, ___ / /// / / /, / / / / / CURRENT VECTORS EXISTING CAUSEWAY· \ 18 em /s = 1/2 em VECTOR 2 3 4 5 KILOMETERS 2 3 4 5 MILES ~ -----------------------------~~--------------·----------------------------::;..---------------- ----------------------~~------------------ --/" ./ / / / / / / / / / / / / / / / / / / / / / / CURRENT VECTORS / / EXTENDED CAUSEWAY 18 em/s = 1/2 em VECTOR o.__.C::::::::::i2--3==4--5 KILOMETERS 0 2 3 4 5 MILES PREDICTED CIRCULATION PATTERNS WIND 10 KNOTS AT 60°, LOW RIVER DISCHARGE PBU Waterffood Environmental Impact Statement 4-37 ----./ / ./ / / / / / / / / / / / / / PRUDHOE 1;3AY /" ./ / ./ / / / / / / / / / / / / / / ----------/ / / / / / / / / ~ / / / / / ------------/ / / / / / / ~ / / / I / / / Figure 4.2-2 0 0 SA Ll N I TY D I FFERENCES FROM EXISTING CAUSEWAY SALINITY IN PARTS PER THOUSAND AMBIENT • 28 PPT 0 2 3 4 5 KILOMETERS 0----====-2---3==::io4-....o!5 MILES PRUDHOE BAY RIVER DISCHARGE REPRESENTATIVE LO FLOW, WEST WIND 10 KNOTS AT eoo SA Ll N I TY DIFFERENCES FROM EXISTING CAUSEWAY SALINITY IN PARTS PER THOUSAND AMBIENT•28PPT 0 2. 3 4 5 KILOMETERS 0 2 3 4 !5 MILES PRUDHOE BAY RIVER DISCHARGE REPRESENTATIVE LO FLOW, WEST WIND 10 KNOTS AT 2400 PREDICTED SALINITY CHARGES INDUCED BY CAUSEWAY EXTENSION PB-U Waterflood Environmental Impact Statement Figure 4.2-3 4-38 The area between the existing causeway and the Sagavanirktok River is a mixing zone for the clearer, usually colder, and more saline, marine waters and the fresh water from the Putuligayuk and Sagavanirktok Rivers. Since nearshore currents are generally westerly during the open-water period, the freshwater discharge fro~ these rivers is diverted to the north and west of DH 3. Some water swings south between Stump Island and DH 3 (Dames & Moore 1980b). Deeper water north of DH 3 is usually stratified. A tongue of marine bottom water commonly extends shoreward along the west side of the existing causeway (Chin et al. 1979a). The causeway!extension would magnify the general water quality patterns (temperatur:e, salinity, and suspended solids) around the existing causeway. M,Jxing patterns of fresh and saltwater would change with the result being\ that relatively warm, turbid, fresh water presently found along the e~st side of the existing causeway would be diverted 1125 m (3700 ft) f~rther offshore (ENE wind condition). The effects of this diversion wd~ld be manifested in larger differences in temperature and salinity across the causeway than currently exist. Values of these parameters would be about the same on the east side of the existing causeway as at present, but fresher water would extend farther offshore along and north of the extension (Appendix D). Temperatures would be lower and salinity higher on the west side,. corresponding to the re- duction in freshwater input around DH 3. These changes would persist westward inside Stump Island and remain essentially unchanged to the west end of the island. Turbidity on the west side of the existing causeway along the seaward one-third is often lower during east winds compared to the surrounding area. This lower-turbidity water results from an eddy formed in the lee of the causeway as currents pass DH 3. As the flow becomes detached from the causeway, a "deadwater" vortex is formed, the interior of which is not supplied by water of higher turbidity {Chin et al. 1979a). The causeway extension could magnify this situation and a larger area of relatively low turbidity might result. Dissolved oxyg'en levels are normally high, and it is anticipated that the causeway extension would not cause any significant changes. The effect of·. the causeway extension on nutrients would be varied. Silicate concentrations are highly variable with higher silicate values generally occurring near shore and lower values off shore. Consequently, the extension could alter local silicate concentrations, but productivity would not be affected since silicate is not a limiting nutrient in these waters (Schell 1974). Phosphate is also a nonl imiting nutrient, so minor changes around the causeway should have little or no effect. Productivity in coastal marine waters is primarily limited by nitrogen. Since river discharges are high in nitrogen, the diversion of fresh water farther offshore could reduce productivity along the west side of the causeway and in the eastern end of Simpson Lagoon. Available data do not permit an estimation of the effect of the causeway extension on nitrogen availability in this area. 4-39 The proposed 15.2-m (50-ft) breach should have little effect on predicted overall circulation and water quality patterns. Modeling efforts (Appendix D) considered a culvert breach 6 m (20 ft) wide and found only minimal salinity changes (about 0.2 ppt) under "normal" conditions due to the relatively small volume of water passing through the breach compared to the volume moving north or south through the pass between the causeway and Stump Island. Estimates of current velocity through the breach (see Appendix D) indicate that, under typical 10-knot east wind conditions, current velocities would be about 15 cm/s (0.5 ft/s). It is extremely difficult to accurately assess the construction and operation impacts on coastal processes because of the lack of definitive information. The studies conducted to date are limited to photographic interpret at ion of shore 1 ine eros ion a 1 rates, short-term wave measure- ments on the causeway (and at a few locations in the western end of Simpson Lagoon), and an estimate of littoral drift rates from sediment accumulations at the base of the causeway on its eastern side. A numerical wave refraction and sediment transport analysis, described in Appendix I, does not provide actual transport rates in quantitative terms. Rather, it gives an estimate of the capacity of longshore currents to carry sediment. The availability of sediments from both the east and west would be required to define rates of transport. Beach and coastal processes, except for extreme storm conditions, generally involve long-term changes. As such, no significant impacts to the coastal area should result during construction. Additional fine- grained sediments would enter the water column as a result of dredging activities and increased boat traffic, some of which would be carried shoreward by waves and currents. However, circulation modeling indi- cates that most of these sediments probably waul d be transported away from the causeway area and settle to the bottom or be deposited in sheltered areas. Erosion and littoral drift of causeway material may act to fi 11 in the breach and thereby necessitate regular dredging rna intenance. Velocities through the breach should prevent this from happening, however, and would be likely to cause some local scouring of the bottom in and near either end of the breach. Over the long term, construction of the proposed extension could produce significant changes in the shoreline configuration, particularly to the west of the causeway (Appendix I). Increased sheltering from waves from the east and northeast would occur in the east portion of Simpson Lagoon and on the east end of Stump Island. Owing to this sheltering, waves refracted around the proposed extension and directed toward the west could strike Stump Island well downwind of its eastern end. Such a wave pattern would allow beach erosion to proceed on the west er\d of this island while protecting the east end. Winds from the west wou 1 d tend to move Stump Is 1 and sediments to the east, as is now the case, extending that end of the island. Circulation 4-40 ; modeling studies (Appendix D) show an area of low current velocities near the east end of Stump Island that would also encourage deposition in this area. Potentially these factors could lead to closing of the inlet between the island and the causeway. The tendency to close would be enhanced should a. new channel be cut somewhere on Stump Island, a situation that could result from wave erosion due to the east winds described above. The likelihood of complete closure of this pass cannot be assessed but is judged to be low. Should this closure occur, the impacts should be localized to the area near the present causeway and its extension, including Simpson Lagoon to the west end of Stump Island. Dredging might be required to maintain free passage of water through this gap and would add to the cost of the proposed project. Modeling studies indicate no significant changes in flow rates through Simpson Lagoon (behind Stump Island) under the proposed alternative. However, these studies did not evaluate effects of potential changes in coastal morphology other than the proposed construction. No significant impacts to the marine ice environment are anticipated from construction activity for the proposed alternative if marine structures are placed during summer when the area is generally free of ice. However, as soon as such structures are placed in the marine environment, and unt i 1 such structures are removed or naturally des- troyed, a number of changes likely would occur in the local ice regime. During the open-water period, alterations in currents would change the movement of remnant ice in the area, and the frequency and distribution of ice gouging. Some ice pile-up, grounding, and increased bottom gouging may result upwind and north of the causeway extension, while downwind in the "shadow" of the causeway there would be less ice and less gouging. During the ice-covered period, the causeway extension would obstruct movement of the ice sheet in a period when it is driven more by wind than currents. An area as wide as 10 m (33 ft) around the causeway would become bottomfast ice (assuming 2m, 6.5 ft, of vertical ice growth and a 1:5 side slope for the causeway). The combination of this bottomfast ice and the physical obstruction of the causeway exten- sion should stabilize the ice sheet locally, particularly downwind in the "shadow" of the causeway. During breakup, Kuparuk River discharge floods the surface of the sea ice, spreading east, north and west from the river's mouth. The water's movement to the east is blocked by the existing causeway. The discharge has been observed to pile up on top .of the ice on the west side of the causeway and be forced north between Stump Island and DH 3. The cause- way extension may further affect the distribution of this Kuparuk spring discharge, which is high in suspended solids and probably also in nutrients. The magnitude and significance of these effects is not known. However, if this represents a significant input of nutrients or organic material to the lagoon system, then the proportion remaining within the lagoon would increase somewhat, perhaps increasing the productivity of the lagoon. 4-41 The marine ice environment could cause several severe impacts to project structures. Ice movement near the proposed causeway extension could result in ice pile-up, ride-up, or override. Ice pile-up or ride-up may occur within a period of less than 30 minutes at any time of the year but occurs most often in the spring and fall (Kovacs and Sodhi 1979). Although the proposed structures waul d be located with in the shorefast ice zone, this location is not sufficiently stable to exempt the struc- tures from ice forces. Computer models of ice pressures on structures considered by the oil industry for construction on the shallow coastal shelf of Stefansson Sound have shown that ice pressures can be immense and destructive, but that damage can be minimized by engineering design (Jahns 1979). A recent study conducted by Hardy Associates Ltd. ( 1980) assesses some of these p:otent i a 1 impacts to the proposed project (Appendix J). They conclj,~de that for some typical properties of sea ice: i\ ' j. ,. Ice ride-up is ~~ possibility for the proposed embankment configuration. ·· Embankment instability from ice push should be a definite concern as ice forces are in the same order of magnitude as the embankment resistance. (This need only be a concern for the first year or two until natural freezeback has penetrated the embankment.) Basal failure of the causeway from ice push should be a concern if the foundation soils are considerably weaker· than the fill material (if they are fine-grained silty clay or clay soils). This need only be a concern until natural freezeback has penetrated the foundation soils. Weeks and Kovacs (1979) have indicated that, within the lagoons and sounds behind the barrier islands, ice ride-up and override can advance 46 m (150 ft) or more inland regardless of ice thickness. Under the proposed design, ice ride~up would have to advance overland 58 m (190 ft) from the west or 82 m (270 ft) from the north or ea~t to threaten the seawater treating plant facility. Although this distance is greater than that observ~d by Weeks and Kovacs (1979), the possi- bility of an extreme ride-up event should not be excluded. Pipelines buried in the causeway could be susceptible to ice gouging during ride-up events. However, their proposed burial at least 1 m (3 ft) below the causeway surface should be sufficient to protect them from ice gou~ing. Fine-grained bottom sediments in the causeway extension area are described in Section 3.8 and Appendix C. Cores in Prudhoe Bay pene- trated as much as 10 m (33 ft) of Holocene or older marine mud described as interbedded sandy silt and silty clay (Hopkins and Hartz 1978). In the borehole nearest to the causeway extension, about 2 km (1.2 mi) east, this layer was about 3m (10ft) thick. In light of these soils and concern for the possibility of basal failure of the causeway, it is 4-42 suggested that site-specific soils strength information be acquired for proper engineering and that the rate of frost penetration in the causeway fi 11 and found at ion soi 1 s be estimated to determine the duration of hazard. Hardy Associates ( 1980) emphasize that ice strength and mot ion data should be obtained for the ice type and temperature conditions at Prudhoe Bay. Their ice force estimates use only typical properties of sea ice, which may not represent the worst possible case in the Prudhoe area. In their calculations they use values of 91 -113 kg/cm2 (200 - 250 1 b/in2) as the crushing strength of sea ice. Shapiro ( 1980) has indicated that, for probable strain rates in naturally occurring ice events, these are reasonable strength values if the ice is warmer than -5°C (23°F). However, colder ice may extend forces of 181-227 kg/cm2 (400 -500 lb/in2) before failing. Although the ice in the project area is generally most stable in mid-winter when these cold temperatures occur, the possibility of an event occurring during cold conditions with forces 50-100 percent greater than those projected by Hardy Associates are not out of the question. It is possible that these peak crushing forces may not be realized over broad fronts such as the seawater treating plant or causeway extension, as little is known about how ice forces are distributed across a broad front. Ice gouging is a potential hazard to both proposed outfall lines. As described in Sect ion 3 .8, ice gouges are generally less than 60 em (2 ft) deep in the project area. The top of the marine 1 ife outfall pipeline would be placed 1.3 m (4.3 ft) below the seabed and the main outfall pipeline 1 m (3.2 ft) below the seabed. The top of the outlet for the marine life outfall and the diffuser nozzles of the main outfall would be 0.9 m (3 ft) below the seabed level and would not be buried. These values represent a 50 percent safety margin from the gouge depths that have been observed, but may not be sufficient to allow for an extreme event. Reimnitz and Maurer (1978) indicate that individual ice pieces '11 rolling and pounding with the waves (of a severe storm) might impact the bottom to greater depths than those of long continuous ice gouges and thereby endanger buried pipelines." The breach in the causeway should not have any effect on the marine ice environment; however, sea ice may constitute a hazard to the purpose and the structural integrity of the breach. Ice may partially block the breach to biological migrations early in the open-water period although it is expected to retain open water under the surface ice. Careful engineering waul d be required for the breach abutments to maintain the structural integrity of the causeway under the forces associated with ice movement and ice growth. Alternative B (Gravel Island) The construction of an island near the 3.7-m (12-ft) contour would not create any significant impact to the coastal area. Some local wave 4-43 / / sheltering would occur directly in the lee of 'the structure. Neither the existing causeway, Stump Island, nor the channel between them would be significantly affected. Circulation changes and secondary water quality effects should be minimal. Modeling results predict salinity changes less than 1 ppt regardless of the wind conditions. This alter- native would require an increase in the amount of dredging and result in slightly greater temporary effects on turbidity than the proposed alternative (Section 4.2, Marine Biology). Sea ice impacts would be similar but smaller in magnitude to those of the proposed alternative. Alternative C (Dredged Channel) Coastal impacts from this alternative woulq be similiar to existing condition~. The end of the causeway would jpe enlarged to accommodate the treatmg plant and a 3.7-m (12 ft) chanf\lel would be dredged to the 3.7-m contour. Much of the material accumulating on the eastern base of the existing causeway originates from the )~auseway. Increasing the amount of material at DH 3 would contribute a very small additional sediment source and increase accumulation at the base. Owing to its small dimensions, the dredged channel would be practically invisible to waves and currents passing over it. No changes in circulation would be anticipated other than perhaps a greater tendency for marine waters to move onshore through the deeper channel. This alternative would require an increase in the amount of dredging and thus would create greater short-term impacts on water quality, primarily water clarity, than the proposed alternative (Section 4.2, Marine Biology). This alternative would be least damaging to the sea ice environment and would be 1 east threatened by ice-gouging damage to piping. Accidents Petroleum product spills or leaks during construction would adversely affect marine water quality. The degree of impact would depend upon seasons, location, duration, and volume, and on the timeliness and effectiveness of containme~t and cleanup activities. Operation Impacts Alternative A (Proposed by Applicant) Operation of the proposed seawater treating pla'nt would have negligible impact on coastal processes and sediment transport. Potentia 1 impacts of the discharges and sea ice are discussed below. The volume of the intake and discharge should have little impact on general circulation during the summer open-water conditions but may cause significant changes to under-ice currents. Intake volume represents about 4 percent of the estimated flow north or south through the inlet between the causeway and Stump Island during open-water 4-44 conditions, and the maximum discharge represents only about 1 percent. As such, no significant effects would be expected. However, currents under ice may be an order of magnitude 1 ess than during open-water conditions, and considering that the water cross-section is signifi- cantly reduced due to the presence of up to 2-m (6.5-ft) of ice, the intake and discharge may be the dominant forces driving currents for an area up to 1 km ( 0. 6 mi) or more away. The s i gni fi cance of any changes is not known but the magnitude of under-ice currents should remain small and biological impacts should be negligible. Seasonal effluent composition and flow rates are presented in Table 2.5-2. The effluent standards that must be met are provided in the draft NPDES permit. The annual average flow rate would be 0.19 m3/s (2915 gal/min). Minimum flow would occur during winter (0.18 m3/s, 2800 gal/min) and maximum flow would occur in summer (1.1 m3/s, 17,325 gal/min). The discharge would be located some 300 m (1000 ft) north of the treating plant in 4.3 m (14 ft) of water. Since Beaufort Sea water is relatively unpolluted, and because the only proposed additives are a biocide and a coagulant, it is anticipated that none of the 65 toxic pollutants listed in EPA's priority pollutant toxic list (BNA 1979) would be detectable in the discharge. Certain seawater parameters would be essentially unaffected by the treatment process. Salinity would not exhibit a measureable change and the pH of the effluent would range between 7.6 and ·7.9 (AOGC 1980). Nutrient concentrations, particularly the dissolved components of nitrate and orthophosphate (the components utilized by aquatic biota) would not be reduced by the treating process. A slight increase in nutrient concentrations could result from breakdown of discharged organic material (e.g., entrained organisms). However, decomposition rates are so slow relative to nutrient uptake rates by primary producers that the effects would not be detectable. Water temperature waul d be changed during treatment. According to the applicant, the estimated temperature of the outfall would be: Winter, oc (°F) Summer, oc (°F) Minimum -1.9 ( 28.5) -1.5 (29.3) Average -1.1 ( 30) 2.6 (36.6) Maximum -0.8 {30.5) 8.5 (47.3) They also estimate that there would be no difference between the discharge and receiving water during summer, and a 1.1°C maximum difference during winter. These values appear reasonable. The smallest temperature differential should occur during summer when ambient seawater temperature is above freezing, and when heated water would not have to be added for freeze prevention. The largest differential would occur during winter when ambient seawater is near -2°C (28°F). Seawater coming into the plant would be heated to 0.8°C (33°F) and immediately upstream of the filters it would be heated to 4.4°C (40°F). The filter 4-45 backwash would be heated to 0.8°C, but the water in the filters would be 4.4°C. On a daily average basis, the combined filter material, filter backwash, and screen wash would result in a temperature of 0.9°C (34°F) at the diffuser, assuming no heat loss through the discharge pipe. At the edge of the Alaska Department of Environmental Conservation (ADEC) mixing zone the temperature would be -1.9°C (29°F), as compared to the ambient temperature of -2°C. This would comply with Alaska water quality standards (ADEC 1979). The mixing zone would extend 305 m (1000 ft) from the diffuser in all directions, making a total area available for mixing of ro1;1ghly 40 ha (100 acres). At any one time, however, actual mixing witHin this zone will encompass less than 8 ha (20 acres). Mangarellaf {1980) estimated an average dilution factor of 50 for this zone und~r rough ice. This dilution factor is also used for open water as a wa'fst-case estimate. L ;!. The average annual total suspended sol ids (TSS) concentrat io~ in the discharge would be 207 ppm (see Table 2.5-2). The daily average TSS concentration would range from 92 ppm during winter, when the ambient concentration in seawater is 9 ppm, to 726 ppm during summer storms when the intake water would have 150 ppm TSS. The average open-water TSS concentration in the discharge would be 525 ppm. TSS concentrations at the mixing zone boundary should meet State. standards at the proposed diffuser location. The Alaska water quality standards for marine water use (Class C, growth and propagation of fish, shellfish, aquatic life, and wildlife including seabirds, waterfowl, and furbearers) state that suspended sediment shall have "no measurable~increase in concentrations above natural conditions" (ADEC 1979). The excess TSS concentrations, in ppm, at the edge of the mixing zone would;,be: Daily Average Excess Ambient Open-Water Open-Water Maximum Average 15 150 10 25 Under-Ice Average 2 9 Although these daily average TSS excess concentrations are above ambient, three factors indicate that TSS concentrations will meet the "no measurable increase in concentrations above natural conditions" standard. First, the dilution factor of 50 is a worst-case value for open water. Wind-induced currents and mixing are likely to increase the dilution factor. Second, the natural variation of TSS concentrations in the area during open water is usually greater than the excess TSS concentrations. For example, TSS samples collected during 24-hour periods for design of the Waterflood Project at one site north of DH 3 at about the 2.7-m (9-ft) depth displayed the following ranges (Metz 1980a): 4-46 Date TSS Range, mg/1 Number of Samples 7/16/78 41.9 -166 7 7/17/78 56.2 -190 31 7/18/78 66.8 -96.0 5 7/19/78 31.0 -161 10 7/20/78 12.4 -35.5 11 7/21/78 6.0 -22.5 12 7/22/78 3. 7 -32.3 12 7/23/78 5.4 -23.1 12 7/24/78 5.2-17.7 11 Studies by Chin et al. (1979a) have obtained similar results. Third, the precision of the TSS test indicates that analytical error is about the same magnitude as the TSS excess concentrations. The American Public Health Association (1975) notes that precision varies with concentration. At a TSS concentration of 15 mg/1 the standard deviation is +5.2 mg/1 with a coefficient variation of 33 percent, and at 242 mg/1 the standard deviation is +24 mg/1 and the coefficient of variation is 10 percent. Consequently-;-excess TSS concentrations are not likely to be measurable above natural conditions at the edge of the ADEC mixing zone. Solids accumulation on the seabed downstream from the diffuser would not be anticipated during the open-water season. Under most conditions, current speed and wind mixing would be adequate to remove sediment from the area. During winter, however, when ambient currents are practically zero, solids would settle out of the water column and accumulate on the seabed. The area of sediment deposition under-ice would be less than 8 ha (20 acres), and would have an average depth of accumulation of less than 0.2 em (0.1 in) (Mangarella 1980). Sediment would not accumulate evenly. Although sediment would accumulate during W'inter, it would not become deep enough to become a permanent feature by freezing. The permafrost table in the area is deeper than 1.5 m (5 ft) below the surface (Peterson 1980). Consequently, there would be 1 ittle chance for the permafrost table to rise into the accumulated sediment and freeze it in p 1 ace. Sparse data are available regarding discharged solids composition. Mangarella et al. (1979) noted that 90 percent of the TSS discharged would be fine silt and clay. Suspended sol ids samples collected in summer and winter 1976, exhibited 0 -79 percent loss on ignition or total oxidizable material with a mean of 27 percent. Of six samples collected during open water, the range of loss on ignition was 6.2 - 28 percent, and the mean was 17 percent. Eighteen under-ice samples displayed a range of 0 -79 percent loss on ignition with a mean of 27 percent. Peterson (1980) noted similar results from the analysis-of chemical oxygen demand (COD) of seven samples collected under ice near 4-47 DH 2 and DH 3. He reported a mean of 0.24 mg COD per mg TSS, i.e., a COD that is 24 percent of the TSS. Using this small data base, the COD of the discharge attributable to TSS can be estimated by assuming 17 percent of the TSS during open water and 25 percent of the TSS under ice would be oxidizable. The ultimate question regarding the impact of oxygen demand on water quality relates to the amount of biochemical oxygen demand (BOD). Since no BOD data exist for the Beaufort Sea in the vicinity of the proposed project, BOD values have to be estimated from the COD. The typical relationship between BOD and COD in domestic waste effluent is that BOD is 40 percent of the COD. This relationship is used here as a worst case since silt would not be oxidized by bacteria as fast as domestic waste effluent, where the bacteria are acclimated and present in large numbers. Therefore, the following excess COD and worst-case excess BOD values, by season, are expected: Open-Water Maximum Case Daily average Open-Water Average Case Daily average ·Under-Ice Average Case Daily average COD(mg/1) 120 89 13 BOD(mg/1) 48 36 9 If all the biological matter in the effluent (see Table 2.5-2) were oxidizable by bacteria in 5 days (worst case), none of the BOD values would be affected since the precision of BOD determinations·. is only sufficient to yield two significant figures. Alaska water quality standards for dissolved oxygen (DO) in marine waters as they would apply to this project are: 11 DO concentrations in estuaries and tidal tributaries shall not be less than 5 mg/1 except where natura 1 conditions cause this value to be depressed. In no case shall DO levels above 17 mg/1 be permitted... Oxygen demand outside the ADEC mixing zone would not depress DO levels below 5 mg/1. Applying a dilution factor of 50 for the ADEC mixing zone indicates that an excess BOD of less than 1 mg/1 would occur during all seasons. Since ambient DO levels would be about 11 mg/1 under ice, and since the BOD is oxidized over a period of 5 days, DO would remain well above the 5 mg/1 limit. During summer, DO values normally range between 9 and 14 mg/1. Wind-induced currents and mixing allow for maximum atmospheric reaeration and increased dispersion and dilution. Therefore, DO levels would not be reduced to 5 mg/1 during summer. Low dissolved oxygen levels apparently occur naturally in pockets of seawater trapped beneath ice (Alexander et al. 1974, Tarbox and Spight 1979). The buoyancy of the heated effluent, turbulent mixing near the diffuser, and the diffuser depth should prevent the discharge from being confined to such a pocket. The seawater treating process would consume 4-48 .. : oxygen and potentially reduce dissolved oxygen levels slightly in the discharge. Considering the slow reaction rates of the principal oxidation processes, such as BOD consumption, it is unlikely that a measurable reduction in dissolved oxygen would occur in the discharge stream. It should be noted that domestic waste from personnel operating the seawater treating plant waul d be trucked to the Prudhoe Bay Operations Center for treatment and disposal (WTF 1980). Consequently, there would be no oxygen demand from domestic waste exerted in the Beaufort Sea. A biocide, most likely sodium hypochlorite, would be continuously added upstream from the filters. As stated in Table 2.5-2, chlorine residual would be controlled to approximately 0.1 mg/1 maximum. The only water containing chlorine normally being discharged would be the filter backwash after it has passed through the filters. The backwash supply for the filters, strainers, and screens would 'be unchlorinated. No d~chlorination is planned. Chlorine would react with bacteria, algae, ammonia, and other oxidizable compounds. Some reaction products would be nontoxic (e.g., chloride and bromide compounds), but others, such as mono-and dichloramines have significant disinfecting power. All the potential specific reaction products for this discharge are not known. However, the total chlorine residual at the mixing zone boundary will be less than 2 mg/1, the Alaska water quality standard. The average residence time of the chlorinated water destined to be discharged from the treating system would be approximately 1.5 hours until the next backwash cycle and 20 -30 minutes within the main outfall line. Under anticipated conditions of moderately high salinity at the intake depth, low ammonia concentration, and ample bromide ( 65 ppm; Sverdrup et al. 1942), the dominant early react ion (first 10 seconds) would probably be the oxidation of bromide to form hypobromous acid (Helz et al. 1978). Relatively little cl1loramine would be formed under these conditions (Helz et al. 1978). However, simultaneous application of an ammonium-based flocculant (e.g., Visco 3364) could result in the production of chloramine as the dominant oxidation product. The chlorine dose would be controlled to maintain a maximum residual of 0.1 mg/1 at the out let of the filters. The chlorine dose upstream of the filters is not known because chlorine demand is not known; however, by design it may be as great as 2.5 mg/1. The maximum concentration in the effluent would be less than 2.5 mg/1 because: 1) if the chlorine demand were low, the dose would be reduced to maintain the 0.1 mg/1 residual; and 2) if chlorine demand were high, some portion of the 2.5 mg/1 maximum inlet dose waul d be reduced by the demand. Conse- quently, chlorine concentrations were calculated using 2.5 mg/1 as the worst case and 0.1 mg/1 as the average case. The volume of water in the filters would be 24 m3 (6340 gal), and the volume of backwash would be 4-49 0.15 m3fs (2390 gal/min) for the maximum summer condition, 0.06 m3fs (990 gal/min) for the average summer condition, and 0.04 m3fs (585 gal/min) for the winter condition. Screen wash would be constant (0.14 m3fs, 2215 gal/min) for all conditions, and total discharges would be 1.10 m3fs (17 ,325 gal/min) for maximum summer, and 0.2 m3fs (3210 gal/min) and 0.18 m3fs (2800 gal/min) for the average summer and winter conditions, respectively (Table 2.5-2). With these flow rates, chlorine concentrations, and the near-field dilution factor of 50, the following conservative chlorine residuals, resulting from dilution only, could be expected at the edge of the mixing zone: Summer, Maximum Flow Case, )Jg/1 Summer, Average Flow Case, )Jg/1 Winter, Average Flow Case, pg/1 Worst Case Average Case 0.6 2.7 1.9 0.02 0.1 0.08 These values are conservative since chlorine would react with substances in the backwash water, other wash water in the discharge, and seawater in the mixing zone. Consequently, the chlorine residual in the water at the edge of the mixing zone would meet Alaska water quality standards: .. Concentration shall not exceed 2 ).lg/1 for salmonid fish, or 10 J.lg/1 for other organisms .11 The NPDES permit for this project (Appendix 0) requires monitoring of the chlorine residual in the water, sediment, and in selected biota. Also, the permit specifies a 0.1 mg/1 effluent limit on chlorine residual. Applying the dilution factor of 50 indicates the maximum chlorine residual at the edge of the mixing zone would not exceed 2 )Jg/1. It should be noted that the NPDES permit specifies the offshore discharge location, which has a worst-case dilution factor of 50. The potential for formation of organochlorine compounds is of concern. Glaze and Henderson (1975) cited studies describing the formation of chlorine-containing compounds when secondary effluent is contacted with chlorine doses as low as 10 ppm. The concentrations of the new species found were in the range of 1-50)Jg/l (0.001-0.050 ppm), or 0.01- 0.5 percent of the original dose. Glaze and Henderson (1975) tested the production of chlorinate9 organics in secondary effluents by super- chlorination where they used a chlorine dose of 1500 ppm and a contact time of 1 hour. The total organic-bound chlorine content in the secondary effluent was in the range of 3 - 4 ppm, or 0.2 -0.3 percent of the original dose. In the above cases, chlorination produced chlorinated compounds from the organics found as residues in secondary wastewater effluent. The organic content of secondary effluent is higher than in seawater, and the variety of organics is much wider. Consequently, the likelihood of formation of organochlorine compounds by chlorinating Beaufort Sea water should be lower than when chlorinating secondary effluent. Therefore, a worst case would be to consider that 0.01 -0.5 percent of the chlorine dose could result in the formation of organochlorine compounds. With a dose of 2.5 mg/1, formation of 0.25- 12.5pg/l of or~anochlorine compounds would be the worst case. Although 4-50 specific compounds are not known, their concentration outside the ADEC mixing zone would be low. For example, using the average summer condition, which exhibits the least dilution in the treatment process, the concentration of potentially formed organochlorine compounds would range from 0.003 to 0.014~g/l. Three potential coagulants have been identified for use in the treatment process. The recommended coagulant, Visco Koagulan 3332, is a solution of polyquaternary amine chloride. The others are solutions of poly- aminoesters or polyamines. Amines are substituted ammonia compounds. Unless the ammonia is stripped and combines with chlorine to form chloramines, the ammonia portion would not create adverse impacts to water quality. However, the substituted portions are not known, so prediction of their impact on water quality cannot be made. Recirculation of the effluent back to the intake is of concern. However, the proposed discharge location, 900 m (3000 ft) north of the seawater treating plant, waul d probably not manifest short-circuiting under any condition: Habitats near the diffuser would be disturbed by turbulence from the diffuser ports and by increased sediment at ion by coagulated sol ids and resuspended sediments. Exit velocities at the diffuser nozzles would range from approximately 73 cm/s (2.4 ft/s) if a periodic backwash flow rate of 0.4 m3fs (6240 gal/min) is produced to approximately 271 cm/s (8.9 ft/s) if a continuous flow of 1.1 m3fs (17,210 gal/min) is maintained. These rates would be considerably greater than the 0.00 - 1.15 cm/s (0.00 -0.4 in/s) average flow observed at six stations under the ice (Mangarella et al. 1979). Deflection of the discharge stream off the ice might result in minor ·scouring of the sea floor, but the impact would be relatively slight. Ballast would be added to the seawater treating plant to ground it onto the gravel foundation. A calcium-chloride brine solution would be used as ballast (WTF 1980). If this solution could not be discharged to the Beaufort Sea, it would be discarded in a disposal well in the Prudhoe Bay field (WTF 1980). The volume, concentration, location and duration of discharge would have to be known before potential impacts can be assessed. · Impacts to the marine ice environment from the project•s operation are limited to the main outfall effluent. Discharge at the marine life return outfall should have little impact on the ice canopy as this water would have the same suspended solids concentrations as the intake water and only a slightly elevated temperature. The main outfall discharge would contain higher suspended solids concentration during fall, winter, and spring and would be 0.5° - 1 oc (1 o -2°F) warmer than the ambient waters. If these suspended solids were incorporated into the ice sheet as it grows, a 11 dirtier 11 than normal ice would result. The increased temperature of the discharge waters would slow ice growth in the region of discharge, and result in an area of reduced ice thickness. 4-51 Impacts to operation of the proposed alternative from the marine ice environment may result from frazil ice blocking or clogging intakes. Frazil ice is known to occur in the Arctic, but lack of knowledge about the magnitude and distribution of its occurrence makes it difficult to assess this potential hazard to project operation. The principal engineering solution would be to add heat to the intake waters. Frazil ice problems would be equal for the causeway extension and gravel island alternatives and may be slightly greater for the dredged channel alternative because of the more restricted open-water area between the ice sheet and the sea floor. Alternative B (Gravel Island) Potential impacts of operating the seawater treating plant under this alternative would not differ appreciably from those under Alternative A. The alternative diffuser location for the gravel island intake configu- ration is about midway between the island and DH 3. At this location diffuser performance and discharge impacts would differ from those under Alternative A in that: Dilution within the mixing zone would be reduced. Effects of the discharge on shor.e-fast ice would be increased. Accumulation of sediment would be increased. Effects of turbulence on bottom sediments would be increased. Recirculation of the effluent would be more likely. Alternative C (Dredged Channel) Potential impacts of operating the seawater treating plant under this alternative would differ from those under Alternative A in that: Accidents More TSS would be entrained and discharged during the open- water season. More chlorine demand would exist and more chlorine reaction products would be created. The effluent would have a higher BOD and could have a lower DO concentration. Periodic rna i ntenance dredging wou 1 d increase turbidity. Water quality would be adversely affected by petroleum product spills or leaks reaching marine waters during operation. The magnitude of impact 4-52 would be directly related to season, duration, volume, type of product, and location of spill or leak. The magnitude of impact would also be directly related to the timeliness and effectiveness of containment and cleanup activities. Emergency shutdown of the field could result in the discharge of treated seawater from one or both of the low-pressure pipelines. The seawater in these lines would be filtered, deaerated, heated, and could contain an antifoam chemical, oxygen scavenger, corrosion or scale inhibitor, and a biocide. The approximate volumes of seawater in the low-pressure lines would be 27,000 m3 (7 million gal). It would be highly unlikely to have both sides of the field and all the backups fail at the same time so that all 27,000 m3 would have to be discharged (Section 2.5, Applicant • s Proposed Project). However, this would be the worst-case event. In the event that treated seawater in the supply and transfer 1 ines had to be displaced, natural gas would be pumped into the 1 ines to displace the water to the seawater treating plant. The gas would be separated from the water by two pigs, between which would be a slug of glycol/water. The gas would not be discharged with the water and the glycol/water slug would be caught at the seawater treating plant and would not be discharged to the sea. The stated reaction time between shut-down and commencement of freezing when the ambient air temperature is -48°C (-55°F) would be 66 hours (PBUWTF 1979). This amount of time would make it possible to mix treated seawater with raw seawater prior to discharge through the main outfall line. Since the outfall could carry about 94,400 m3Jd (25 million gal/d), the 27,000 m3 of treated seawater could be diluted with 67,400 m3 (17.8 million gal) of raw seawater if discharged over a 24-hour period. The impact of such an event would be negligible. The absence of suspended solids would be of little concern since the receiving water would contain low concentrations, perhaps up to 9 mg/1. Dissolved oxygen in the outfall 1 ine would be about 7 mg/1, and about 10.8 mg/1 at the edge of the ADEC mixing zone. Marine water would contain about 11 mg/1 of dissolved oxygen. Water temperature in the low-pressure lines would drop from 4.4°C (40°F) to 1.6°C (34.8°F) in the outfall line and to -1.9°C (28.6°F) at the edge of the mixing zone, compared to -2°C (28.4°F) in the receiving water. Any oxygen scavenger and corrosion or scale inhibitor chemicals would be discharged only if the deaeration system had malfunctioned immediately prior to the failure of the freeze protection system. These specialized chemicals added to the treated water would be d i 1 uted by about 40 times before reaching the edge of the ADEC mixing zone (e.g., a constituent at 1 mg/1 would be reduced to about 0.02 mg/1; at 5 mg/1, the reduction would be down to about 0.13 mg/1). These concentrations should be acceptable since a shut-down with resultant discharge wou.ld not be a continuous event. Displaced water could contain up to about 0.25 mg/1 anti-foam chemical (AOGC 1980). Assuming discharge occurred over 24 hours, the . 4-53 • concentration waul d drop to about 0.01 mg/1 at the edge of the near- field mixing zone. This concentration being discharged on a one-time basis should not create adverse impacts to water quality. MAR! NE BIOLOGY Adverse impacts to the marine biota would result from each of the alternative intake configurations and designs. Construction Impacts Potential new adverse environmental impacts that would result from construction of each of three major intake configuration and design alternatives are described below. These alternatives are: the proposed configuration, with the seawater treating plant and intake at the end of an extended causeway; placement of these structures on a gravel island; and placement of the treating plant and intake at DH 3 with a dredged channel to the 3.7-m (12-ft) contour. Alternative A (Proposed by Applicant) Short-term impacts (i.e., effects that would not extend appreciably beyond the period of construction activity) would include or result from: Slightly increased turbidity and suspended sol ids from dredging and filling activities and propeller wash. -Mortality of benthos, plankton, and nekton during dredging and filling. Mortality of fishes during propeller start-up. Avoidance of the area by birds, fish, mammals, and motile epifauna because of the increased noise and activity levels of dredging, boat operations, and pile driving activities. Acute effects on marine birds, fish, and invertebrates resulting from accidental spills of oil, fuel, or other toxic substances. The disjunct construction period, primarily in the open-water season, would coincide with maximum use of the site by marine birds and by resident and migratory populations of marine and anadromous fishes (Appendix E). However, natural turbidities are characteristically high during this season and the area is basically a depositional environment; thus, marine organisms inhabiting the site apparently are adapted to this condition. The natural mixing processes producing high ambient turbidity should also disperse and dilute suspended dredged 4-54 ~ \ material such that no detectable -adverse impacts are expected from increased turbidity. Most. infaunal and some epifaunal, planktonic, and nektonic organisms probably would be destroyed in areas excavated by dredging or covered by dumping of dredged materials. Significant attract ion of scavengers and predators to feed on dead or injured organisms would be expected, as indicated by catches in baited traps (Feder et al. 1976a, Busdosh et al. 1979). Their persistence in spite of periodic losses to ice gouging, shove, storm surge, and sediment freezing demonstrates that these populations would return to previous densities after construction provided that no permanent habitat loss occurs. Epifaunal populations should recover rapidly through immigrations by motile stages. Infaunal populations may require a significantly longer recolonization time, especially since many do not reproduce with planktonic larvae (Feder et al. 1976a). Previous observations indicate that some fish, notably arctic cod, would be attracted to the barges and a port ion of these may be destroyed during propeller start-up (Tarbox and Spight .1979). Total fish destroyed by this activity would probably represent a very small percentage of the estimated arctic cod population in the Prudhoe Bay vicinity. Incre_ased noise from construction, including pile driving and barge traffic, could disturb some marine mammals and birds for distances up to 1.6 km (1 mi). Some species of birds (e.g., black brant, oldsquaw, and eider) migrate along the coast during spring and/or fall with stops in coastal lagoon areas. Construction noise could cause alterations in migration course and displacement from resting and feeding areas in the vicinity of the causeway, possibly resulting in increased stress and a small increase in mortality. Geese are relatively sensitive to noise and activity, whereas oldsquaw are tolerant (NOAA 1978). Small accidental fuel spills are a possible result of construct ion activities. Waterbirds are particularly susceptible to fuel spills and the birds that concentrate within Simpson Lagoon during the post- breeding period (July through September) would be vulnerable. Oil and fuel could drift into the shore zone and adversely affect food organisms of shorebirds and waterfowl. · Offshore extraction of gravel from the seabed could have a variety of impacts on local biota (AEIDC 1980). Major impacts would result from spoiling of overburden, direct loss of benthos, and down-current effects on benthos and plankton due to turbidity plumes. Eastward spring migrations of bowhead whales would pass the western Beaufort Sea well ahead (May-June) of barge traffic bound for Prudhoe Bay (mid-July-August) and would be well offshore. Recent data by NMFS and Naval Ocean Systems Center (Appendix E) indicate that westward movement of bowheads does not reach the Prudhoe Bay area until mid-September to October (most sightings in October), which should be 4-55 well after the barges have left the area. Thus, no impacts are expected (Appendix E, Appendix N). Belukha whales and ringed and bearded seals might suffer minor short-term disruption of feeding and movement patterns du@ to barge traffic and other local construction activities. Long-term impacts, i.e., effects on marine biota that would extend well beyond the period of construction activity, would result from: Loss of soft bottom habitat. Addition of other less productive habitat types. Possible alteration of water quality near the causeway and in the east end of Simpson Lagoon. Possible mortalities of anadromous and marine species due to migration blockage. Attract ion of fish and invertebrates to the intake and discharge structures and trenches. Possible accumulation of organic matter in the trenches. Approximately 27 ha (67 acres) of soft subtidal habitat would be buried by gravel during construction of the seawater treating plant and during extension and modification of the causeway. This loss represent~ habitat occupied by approximately 413 million macroinvertebrates and approximately 190,000 kelp plants, based on densities observed in 1978 -1979 (Chin et al. 1979a). An additional 0.4 ha (1 acre) would be dredged for pipeline channels. Dredged material would be redeposited over approximately 3 ha (7 .4 acres), assuming an average deposition depth of 15 em (6 in). The combined effects of shallow water, storm surges, and ice gouging should prevent persistence of spoil banks in nearshore areas. Some 42 ha (104 acres) of seabed adjacent to these new or modified structures could be impacted to varying degrees by sediments released during construction or by erosion of gravel embankments. A 50-m (164-ft) zone of potential disturbance around fill areas was assumed based on results reported by Grider et al. (1978). Thus, the total seabed area that would be directly affected by the proposed action would be 72.5 ha (179 acres) or about 0.4 percent of the total area between the mouths of the Kuparuk and Sagavanirktok Rivers out to the 6-m (20-ft) isobath (based on calculations by Tarbox and Spight 1979). Although the number of organisms potentially lost appears large, the proportion of local populations affected would be small. Little effect on local food webs would result from this loss. Since the local fauna is adapted to severe disruption and sediment redistribution by shoreline erosion, shorefast ice breakup, and storm surges, the impacts of dredged material deposition would probably be negligible, except on the infauna. Since benthic faunal assemblages • 4-56 vary significantly with water depth and sediment type, dredged channels possibly would be colonized by a fauna different from the previous occupants of the site. Trenches for the outfall pipelines and sheltered areas along the causeway would trap organic detritus including drifting kelp and terrigenous material. This detrital accumulation would attract some invertebrates and fishes by providing food and shelter. Storm surge and wave action would resuspend much of this material, at least seasonally. Natural backfilling of these trenches would occur eventually. ; Be¢ause of the lack of significant previous industrial activity in this ar;~a, the marine sediments do not contain harmful concentrations of tq~ic materials that might be redissolved or resuspended during dredging (Section 4.2, Physical and Chemical Oceanography; Peterson 1980). A s~all increase in nutrient levels in the water column would be expected du¥ing dredging. Although nutrients are generally assumed to limit the growth of primary producers during at 1 east part of the open-water season (Horner et al. 1974), any response to slightly elevated nutrient levels would be difficult to predict because of interactions with other factors (e.g., turbidity, temperature, mixing). Some disruption of fish spawning ar smothering of fish eggs would be possible, especially during any winter filling operations in deeper water (>2 m, 7 ft). The species most affected would probably be the fourhorn sculpin and the bartail snailfish. Since the spatial breeding pattern of fourhorn sculpin (widely distributed vs. discrete nursery areas) cannot be determined from the available data, the magnitude of its potential loss cannot be estimated accurately but can be assumed to be proportional to the area affected. On the other hand, snailfish deposit their eggs on kelp fronds and other hard objects (Tarbox and Moulton 1980), indicating that kelp patches and submerged boulder fields represent discrete nursery areas for this species. These areas are best developed in deeper water and to the east of the project site (Beehler et al. 1979), indicating that this temporary loss would not be critical to snailfish population maintenance. Approximately 5.6 ha (13.8 acres) of submarine gravel surface would be added, and an additional 1.2 ha (2.9 acres) of existing gravel would be resurfaced by widening the existing causeway. Most of this surface would be restructured by continuous ice and wave stresses, and thus should not be extensively colonized. A small amount of solid habitat (exposed portions of outfall pipelines, seawater intake structures, sheetpile bulkhead) would be made available to sessile epibenthic organisms. Further disrupt ion to the longshore migrations of several anadromous fishes, already altered by the existing causeway (Spight 1979), would be expected as a result of the causeway extension. This disruption would be increased by water quality changes, by attraction of the fish to the she 1 ter offered by add it ion a 1 submarine structures, and by effects of 4-57 operating the intake (described below). In 1977 studies (Doxey 1977, Bendock 1977), a limited number of anadromous fish of several species tagged on one side of the existing dock were 1 ater recaptured on the other side at varying distance6 from the causeway. While these studies showed that some large (>200 mm fork length) fish of these species can migrate around the dock, they did not evaluate losses caused by predation or delays in reaching spawning areas, or quantify fish migration success. Fish such as the least cisco, humpback whitefish, broad whitefish, and juvenile arctic char, that apparently follow the coastline during their migrations (Craig and Haldorson 1979, Doxey 1977), would be particularly affected, as would small individuals of all species. Since the causeway would probably not represent a totally impassable barrier (Doxey 1977), longshore migrations probably would not be prevented completely. However, these migrations may be delayed or partially aborted and these fish would be subjected to additional risks from the seawater intake during operation. Inclusion of a 15.2-m (50-ft) wide breach in the extension outside of DH 3 would potentially reduce these impacts significantly because some fish migrating close to the shoreline and following the causeway seaward, seeking a path around it, would be likely to pass through the breach. Losses to fish populations resulting from delayed or aborted migrations cannot be quantified accurately from available data (see reasonable worst-case scenario at the end of Operation Impacts, Alternative A, below). Available information on migrations of anadromous fish in the Prudhoe Bay region suggests there may be three types of movements: Eastward and westward dispersion of fish in springtime from the mouths of their overwintering streams. Possible impacts induced by a causeway could inc·lude reduction in alternative feeding areas and interbasin movements, thus reducing population resiliency and increasing vulnerability to oil spills or other ecosystem changes. Reductions in fish populations available to subsistence activities may also occur. Interruptions at this period, however, are believed to be of lesser significance than during fall migration. Relatively undirected movements during much of the open-water season, primarily in seach of food. Interrupt ion of these movements would be similar to those discussed above. Return migrations in late summer and fall, and perhaps continuing under ice after freeze-up. These movements are strongly directed as fish head for their natal stream for spawning or overwintering. Interrupt ion, or delay of these movements could have a severe impact if spawning is delayed or if adequate overwintering areas are not reached before ice format ion and falling stream flows 1 imit upstream movement. Eastward migrations, in particular, would be affected because of the tendency of the causeway and seawater treating plant to funnel 4-58 migrating organisms toward the seawater intake. Under typical ENE wind conditions, westward migrations of fish (such as juvenile arctic char, least cisco, and broad whitefish) that prefer warmer, brackish water possibly would be diverted away from the eastern end of Simpson Lagoon by the plume of this nearshore water deflected seaward from the end of the causeway, and by changes in water quality induced in the 1 agoon itself. Eddies formed by currents passing the end of the causeway could break up or create discontinuities in water masses being followed by fish (especially on return migrations), causing them additional delays in migration. As suggested by experience with the existing causeway and by using the unverified water quality model as a predictive aid, salinity waul d be e~evated by about 3 - 4 ppt for approximately 60 percent of the open~water season just west of the causeway extension and depressed by a Hsimi 1 ar amount just northeast of this extension (Section 4.2, Physical and Chemical Oceanography). Available data are not sufficient to estimate the numbers of migrating fish that would be af'fected in these waj.$. Observations of the ability of anadromous fish to find their way around long jetties constructed in the mouths of many Oregon and Washington estuaries (e.g., Columbia River, Grays Harbor) suggest that similar adaptations could be made by populations in the Prudhoe Bay area (see additional discussion of breaching in Section 2.5, Other Alternatives). However, requirements of arctic species and the unique conditions of the Beaufort Sea 1 imit the appl i.e at ion of studies conducted elsewhere. Several bird species make long-distance westerly movements along the coast in the late summer and fall (oldsquaw, black brant, ·and wading birds) and presumably orient according to the shoreline configuration. The effect of the causeway on these movements is considered to be minor. The artificial shoreline created by the causeway extension is likely to be heavily used by birds foraging for zooplankton --phalaropes, gulls, and terns (Connors and Risebrough 1979). This addition of foraging habitat could have a beneficial effect on these species. On the other hand, the birds would be attracted to those areas where oil spills are most likely to occur and, thus, may be subjecting themselves to: increased hazards. · Unverffied circulation·· modeling studies (Section 4.2, Physical and Chemical Oceanography; Appendix D) suggest that the causeway extension would exacerbate changes in the water quality regime of the east end of Simpson Lagoon during the open-water season. These changes would be in the nature of a modest (5-15 percent) increase in salinity (and likely decrease in turbidity and temperature) with typical E to NE winds, and a similar decrease (5 -15 percent) in salinity (and likely increase in turbidity and temperature) under the less common W to SW winds. During July through September 1979, NE to ESE winds occurred about 60 percent of the time (Figure 3.12-3) with a persistence on the order of several days to a week (Figure 3.12-2) while WNW to SW winds occurred about 20 percent of the time and persisted one to several 4-59 days. Long-term annual patterns (Figure 3.12-1) are similar. Since establishment of steady state conditions is expected to take at least 1 - 2 days following establishment of a given wind pattern (as indicated by the modeling studies), there would be many instances when the duration of westerly winds would be insufficient for full development of the predicted salinity condition. More persistent easterly winds would be more likely to reach the predicted steady state condition. The biological significance of these hydrographic changes is impossible to predict with certainty because of the lack of knowledge of the behavioral patterns and physiological tolerances of indigenous organ- isms, and because of the uncertainties of the modeling process. However, some information is available that permits discussion of the reasonable range of changes that might result. Modeling predictions and hindcasting (Appendix D) indicate that extremes of salinity (2.2 -27 ppt) expected with the extended causeway at a point about 1 km (0.6 mi) west of DH 2 would be only slightly greater than those observed at present (3.2 -26 ppt) and would occur under similar hydrographic and meteorologic conditions. Organisms living in this area often are longevous (Ell is 1960) and are probably subjected to somewhat greater variation during their lifetimes. Hence the increase due to the extension would not be expected to exceed lethal tolerances of indi- genous organisms. However, subtle changes in one or more element of the physical environment of a community can often have a marked effect on community structure (Dempster 1975). Changes in distribution and abundance of benthic fauna (primarily infauna) apparently resulting from the existing dock have been described in Appendix E (Figures E-1 to E-3). Generally, the less diverse and lower biomass community typical of nearshore waters extends northwest along and beyond the causeway in the area where the model (Appendix D) and field measurements (Spight 1979) show the nearshore waters to be deflected by the causeway. On the west side of the causeway, where field measurements show an even higher salinity than predicted by the model, a more diverse and higher biomass community typical of offshore areas is found. Thus, conditions generated by the existing causeway appear to be adequately persistent to alter the local distribution and abundance of the components of the benthic community depicted in Figures E-1 through E-3, although a portion of this effect may be due to depth effect or other more subtle factors (e.g., altered nutrient, sediment, or detritus distributions). A comparison of current and salinity patterns predicted for the existing and extended causeway cases suggests that this condition is likely to be increased in geographic extent by the causeway extension (Appendix D). The net effect on regional benthic infaunal productivity is expected to be slight. Evaluation of the effects of the existing causeway on benthic commu- nities in the east end of Simpson Lagoon is less conclusive b~cause observed variations are less readily attributable to the existing 4-60 causeway. A general increase in animal density off Point .Mcintyre northwest to the west end of Stump Island (Figure E-1) may or may not be re 1 ated to effects of the causeway. Extrapolation to effects expected from the causeway extension is thus not possible. However, model predictions indicate that any changes in benthic communities that did result from the causeway extension may be limited to areas within 2 - 4 km (1.2 -2.5 mi) of the east side of the causeway and 5 - 7 km (3-4 mi) of the west side; i.e. to near the west end of Stump Island. Some minor changes in benthic communities in this area are 1 ikely but the direction of change is difficult to predict. ·, Recent studies by Griffiths and Dillinger (1980) indicate that a continual immigration of epifauna 1 org.Ani sms appears essential to the maintenance of an abundant food resource for fish and birds in the nearshore areas inside the barrier i~q ands. The causeway extension would not significantly interfere witr epifaunal access to Simpson Lagoon. However, should a serious co~striction develop between Stump Island and the causeway, some reduction of food availability might occur inside Stump Island. The area where population changes are possible would be small relative to the total length of coastline of the U.S. Beaufort Sea (approximately 1.5 percent) and to the proportion of that distance offering a lagoonal habitat of some sort (approximately 2.8 percent). Changes in these areas would include both increases and decreases in productivity. In general, effects of this or other causeways (if built) in the Beaufort Sea are expected to be more noticeable where causeways are constructed in close proximity to barrier islands (as on the west side of the existing dock) than where they are constructed near more open coastlines (as on the east side of the existing dock) due to the potential 11 trapping 11 of effect:s by the barrier islands and the importance of the lagoonal ecosystems. Since anadromous fish usage of these p.otent i ally affected areas is 1 imited to feeding and migration (discussed above), changes in their local abundance would be likely to folloW changes in food availability and changes in migra~ion patterns, perhaps induced by altered salinity. Marine fish such as arctic cod that appear to concentrate along the interface between marine and coastal waters (Moulton et al. 1980) likely would alter th~ir local distributions to reflect changes in this boundary caused by the causeway extension. Some increases in the already large numbers entering Simpson Lagoon (Craig and Griffiths 1978, Craig and Haldorson 1979) might be expected under east wind conditions when salinities would be raised in the east end of the lagoon. Alteration in the abundance and/or distribution of marine invertebrates within Simpson Lagoon for any of the above reasons would affect bird populations that depend on the 1 a goon and shore habitats for foraging. Post-breeding concentrations of oldsquaw, red phalarope, and other shorebirds would be most affected. The foregoing discussion suggests 4-61 that net productivity would not be affected greatly but that distribu- tion of organisms caul d be changed. Bird populations caul d be reduced if their food supply is diminished in preferred feeding areas. During most of the year when the sea ice cover is virtually complet~ in this area, the causeway extension should exert little influence on marine distributions of fish, birds, or invertebrates. Potential changes in sediment transport and deposition regimes (see Section 4.2, Physical and Chemical Oceanography) could greatly alter the distributions of benthic and pelagic populations, the migrations of anadromous and marine fish, and the foraging patterns of birds. The most significant of these potential changes would probably be the elongation of Stump Island toward the causeway (Section 4.2, Physical and Chemical Oceanography). This development could restrict movements of water, fish, and motile invertebrates between eastern Simpson Lagoon and offshore areas. Resultant water quality changes could contribute to this physical barrier and cause permanent changes in the nature of benthic communities on both sides of Stump Island. The increased salinity to the west of the causeway predicted by the modeling results (Appendix D) probably would become more pronounced on the offshore side of the island with reduced input from the Kuparuk River through Simpson Lagoon. On the other hand, the east end of Simpson Lagoon probably would become less saline, especially during westerly winds or high river flow. These effects on the biota would become more widespread if compensatory flow developed to the west of Stump Island, deepening and widening that cut. Anadromous fish that normally migrate along the shoreline within Simpson Lagoon could be directed out along the outer side of Stump Island, producing greater changes in their migration routes than that resulting from the causeway extension itself. Additional causeways that may be required for future developments along this coastline would place additional stresses on regional populations, especially those of anadromous species whose natural migrations would cause them to experience more than one causeway-related delay. Perhaps the most crucial aspect of multiple causeways in the Beaufort Sea would be their potential to delay fish beyond their ability to successfully return to natural spawning and overwintering areas. The second crucial aspect of multiple causeways would be their potential to alter water quality conditions within a significant portion of a lagoonal system to the point that large-scale changes would occur. An example might be construction from Storkersen Point (just east of the Kuparuk River) out toward or past Egg Is 1 and. Such a structure waul d severe 1 y reduce easterly flow of fresh water into the area behind Stump Island, which is already similarly affected by the existing causeway. The effects of location of the proposed and future causeways with respect to barrier islands, freshwater sources, and other causeways clearly requires careful consideration. 4-62 r : i Alternative B (Gravel Island) Placement of the seawater treating plant on a gravel island connected to the existing causeway (DH 3) by buried pipelines would alter the impacts described above (Alternative A) in the following respects: Approximately 7.9 ha (19.5 acres) less soft bottom habitat would be permanently covered by gravel. Approximately 3 ha (7 .4 acres) less new gravel surface would be permanently added. Approximately 2.7 ha (6.7 acres) more soft bottom habitat waul d be temporarily removed by dredging. i.( Approximately 12 ha (29.6 acres) more soft ~'attorn habitat would be temporarily buried by dredged materi~L assuming a deposit 15 em (6 in) deep. New habitat available to potential fouling organisms would not be significantly changed. Longshore migrations of fish and invertebrates would be essentially unchanged from the existing condition. Water quality changes would be much less significant near the causeway, and no changes would be expected in Simpson Lagoon. Stump Island would not be affected. The distribution of infacinal assemblages would not be significantly altered beyond the immediate vicinity of the island and pipeline trenches. Since this alternative waul d not require a causeway extension, the gravel requirement would be reduced by approximately one-half. However, significantly more dredging would be re~uired for the additional 1125 m (3700 ft) of buried pipeline to the island. Short-term impacts, in addition to those described above for Alternative A, would be derived primarily from the extended duration of dredging activities. These activities caul d prolong the period during which turbidity would be increased by approximately 500 percent, and the period during which birds, mammals,1 and fish would possibly avoid the site by a lesser amount, depending on the overlap with other construction activities. Major long-term impacts would be lessened by a significant (41 percent) reduction in the area of soft bottom habitat that would be buried by gravel, a comparable reduction in new gravel habitat provided, and a significantly smaller (virtually nonexistent) disruption of the 4-63 longshore migrations of anadromous fish. Fish that follow the shoreline during their migrations would be able to pass the causeway without changing their route and without encountering the intake structure. Long-term disruption of soft-bottom habitats by pipeline dredging would probably be negligible because of natural backfilling, accelerated by storm surges and ice gouging and shove. These areas would probably be rapidly recolonized by a biological assemblage closely resembling the· pre-existing biota, as indicated by the recolonization of areas routinely disturbed by ice gouging, bottomfast ice, and sedimentation. Modeling results indicate that the effect of the gravel island on circulation and water quality would probably be negligible, except in the immediate vicinity of the island (Appendix D). Alternative C (Dredged Channel) Placement of the seawater treating plant on a gravel platform adjacent to the existing dockhead with connection to the 3.7-m (12-ft) depth contour via a dredged access channel would alter the impacts described for Alternative A in the following respects: Approximately 15 ha (36 acres) less soft bottom habitat would be covered by gravel. Approximately 15.9 ha (39 acres) more soft bottom habitat would be removed by dredging. Approximately 60 ha {149 acres) more soft bottom habitat would be buried by dredged material, assuming that the spoi 1 is deposited within 90 m (300ft) of the channels (i.e., spoil depth= 30 em, 12 in). Longshore migrations of fish and some invertebrates would probably be less disrupted. Accumulation of kelp and detritus and the presence of deeper water in the access channel would attract 1 arge numbers of scavengers to the area and cause a significant redistribution of local populations. Because of the low reliabiilty of this alternative, it is not discussed further here (see Section 2.5). Operation Impacts Potential effects resulting from operation of the seawater treating plant are described below. These effects are presented for each of the three configuration and design alternatives considered above (Construction Impacts). 4-64 Alternative A (Proposed by Applicant) Short-term impacts, i.e., effects that would not extend appreciably beyond the period of operation, would include or result from: Entrainment of organisms in the intake stream. Loss of organisms due to mortalities in the marine life return system. Discharge of heat as well as coagulants and biocides and chemicals alien to the natural system. Enhanced growth of sessile organisms in the intake structure. Physical and chemical disruption of pelagic and benthic habitats near the discharge diffuser. Phytoplankton, zooplankton, fish, and some motile benthic invertebrates (e.g., amphipods, isopods) present in the intake vicinity would enter the seawater treating plant through the submerged intake openings in the side of the seawater treating plant and could become entrapped. Intake velocities have been selected (see Appendix H) to prevent velocity- induced entrapment of larger and/or older organisms. However, initial entrapment due to the behavior of some fish species, notah·ly arctic cod, is expected. Presence of the intake would constitute a radical break in the existing shallow slope of natural and causeway-created shoreline. Small, migrating anadromous fish would be forced to cross over this deeper water, where they could be vulnerable to a varietY of predators. Their behavioral tendencies should cause them to hug what shoreline is available, bringing those that do not pass through the:' breach to the immediate vicinity of the intake. Those remaining in the surface layer (top 1 m, 3.3 ft) probably would not be affected by the intake, although their reactions to the darkened opening might cause them to enter or avoid the intake. Induced currents would be too weak to be sensible by fish or to induce entrapment at distances of more than a meter or two from the intake opening. A very small portion of entrapped organisms may be damaged by the intake screens. Virtually all larger organisms (generally >60 mm, 2.4 in) would bypass the screens with little or no contact and would be returned to the sea via the marine life outfall. A portion of smaller fish (50 -70 mm) would pass through the screens (become entrained). Table 4.2-4 1 ists vulnerable periods for several important fish species. Fish available for bypass would be primarily those too large (52 -100 mm or larger, depending upon species) to fit through the screens. Velocity in the intake channels should be great enough to discourage long-term residency and to carry entrapped fish into the return system. Mortality of 4 percent or less due to impingement, abrasion, stress, and 4-65 -· . .-. ,, n ,, ~,. I i· \.'. !!-. .f::> I 0\ 0\, J Species Marine Fish: Arctic Cod Fourhorn Sculpin Anadromous Fish: Arctic Char Arctic Cisco Least Cisco Broad Whitefish Humpback Whitefish TABLE 4.2-4 VULNERABILITY OF IMPORTANT SPECIES TO INTAKE OPERATION IMPACTS IMPACT TYPES Life Stage Eggs Larvae Juveniles Adults Eggs Larvae Juveniles Adults Eggs and Larvae Juveniles Adults Eggs and Larvae Juveniles Adults Eggs and Larvae Juveniles Adults Eggs and Larvae Juveniles Adults Eggs and Larvae Juveniles Entrapment Return System Trauma(l) Velocity Behavioral +Nov-May +Apr-Aug +Aug-Sep +Jul-Aug +A 11 Year +All Ye~ ~11 ~~ +All Year +All Year - - - - -(negligible impact)- +All Year +All Year - - - - - -(no +Jul, Aug +Jul, Aug - - - - - -(no +Jun-Sep +A 11 Year +A 11 Year impacts) - - - +Jul, Aug +Jul, Aug impacts) - - - +Jun-Sep Entrainment +Nov-May +Apr-Aug +A 11 Year ( 2) +Jul-Aug +All Year(2) - - - - - - - - - - -(no impacts) - - - - - - - - - +Jul-Sep +Jul-Sep - - - - - - - - - - -(no impacts) - - - - - - - - - - - - - - - - - - - - -(no impacts) - - - - - - - - - (l)Return system trauma includes all potential lethal and sublethal effects of passage through the intake, bypass, and marine life return systems. (2)A portion of the smallest juveniles may be vulnerable to entrainment. ,,,,. asphyxiation could occur among bypassed fish (see Appendix H). A 10 percent loss could occur due to the proposed impeller pump and general handling mortality in the return system. Moulton et al. (1980), using acoustic techniques, measured densities of fish (all species) in the water column off DH 3 as high as 50.7/10,000 m3 during August 1979. Assuming that these fish, mostly arctic cod (>60 mm total 1 ength), would be entrapped and bypassed in proportion to their densities in the water column (a non-conservative assumption for a worst case, compensated for below), 304 fish/d would be lost (50.7 fish/10,000 m3 x 400,000 m3Jd intake flow x 0.15 mortality rate = 304 fish/d). Densities of less than one-half of this level were reported in July. In a 100-day period (July -September) when arctic cod are expected to be found in the intake vicinity, an estimated 23,000 fish would suffer mortality (assuming 50 days at 304 fish/d and 50 days at 152 fish/d). If all were arctic cod, this would constitute less than 0.1 percent of the 28 million cod estimated to be present in the Prudhoe Bay area in August 1978 (Tarbox and Spight 1979). For a reasonable worst-case scenario and to account for behavori al reactions and demonstrated high arctic cod densities around the existing causeway, a safety factor of 35 was applied, giving an estimated 3 percent reduction factor, assuming no compensatory survival. This factor was considered applicable to other marine species in the area. The greatest impact of intake operation, in terms of numbers of fish affected and their mortality rate, would occur among entrainable fish (generally <60 mm). Because of their size, small fish are less able to resist the velocities inducing entrainment than are large fish; however, some would be bypassed into the marine life return system. Furthermore, 100 percent mortality among entrained fish must be assumed. The 1 ife stages most vulnerable to impingement and entrainment include eggs, larvae and young-of-the-year of arctic cod, fourhorn sculpin (<52 mm total length), and snailfish. These are all forage species that are used as prey by fish predators in the area. The number of fish that might be entrained was calculated using limited available data and is presented in Table 4.2-5. These calculations indicate that a very small proportion of the fish (all life stages) present in the Prudhoe Bay area would be subject to entrainment. It was estimated that potential entrainment would probably remove 1 ess than 0.01 percent of the equivalent adult arctic cod present in the project area. As a reasonable worst case, a 0.1 percent loss was assumed (Appendix H) and applied to all vulnerable marine species. Because of the relatively small numbers of fish likely to die, and because of the potential for a compensatory increase in survival of remaining fish to partially offset entrainment losses, total combined losses due to entrainment and other intake related mortality would be small. The impact upon fish populations in the Prudhoe Bay area would not be significant. 4-67 TABLE 4.2-5 POTENTIAL 6.5-MONTH ENTRAINMENT OF FISH EGGS AND LARVAE BY THE WATERFLOOD INTAKE BASED UPON DATA COLLECTED FROM FEBRUARY 13 THROUGH SEPTEMBER 1, 1979(a) Taxon Eggs Larvae: Arctic Cod(b) Fourhorn Sculpin Snailfish(c) Unidentified Larvae Total Larvae Estimated Number Entrained 5,856 239,648 163,220 397,179 6,076 806,122 (a)source: Based on average ichthyoplankton densities measured in the intake area by Tarbox et al. ( 1979) and Tarbox and Moulton ( 1980); extrapolated over the intervals between samplings and extrapolated to the volume of the intake; see Appendix H. (b)Includes larvae definitely and tentatively identified as arctic cod. (c)rncludes larvae definitely and tentatively identified as snailfish. 4-68 Phytoplankton and zooplankton (including meroplankton) would be entrained through the intake screens and, once entrained, wou 1 d experience 100 percent mortality. No data are available to allow a quantitative estimate of entrainment losses. However, it is expected that losses from plankton populations in the area would be in proportion to the amount of water withdrawn from the area unless some factor caused plankton to concentrate in the vicinity of the intake. Since the volume of water withdrawn would be small relative to the amount available in the area, losses of phytoplankton and zooplankton should also be small. After passing the intake screens, the stream would be treated with heat, biocide, and a coagulant, which should have the desired effects of destroying the remaining 1 iving organisms and coagulating the smallest of these anq other suspended solids so that they can be easily filtered from the stream before injection. These coagulated solids and any residual biocide and coagulant (backwashed from the strainers and filters) would then be discharged through the main outfall {Section 2.5, Applicant's Proposed Project). The EPA (1976), based on a review of literature, has established a criterion of 0.002 mg/1 as a level of total residual chlorine that is expected to protect the health of salmonid fish continuously exposed in fresh or saltwater, and a criterion of 0.01 mg/1 for other marine organisms .. As noted above, 0.002 mg/1 is also the State of Alaska criterion for chlorine residuals. DeGreave et al. (1979) have criti- cized the EPA criteria and, based in part on more recent 1 iterature, have suggested a criterion of 0.003 -0.005 mg/1 for all organisms in fresh water·~ They indicate 0~02 mg/1 as the best avail able criterion for all species in saltwater, although they note than Bellanca and Bailey (1977) have indicated that 0.01 mg/1 was harmful to some economically important marine organisms. Stober and Hansen ( 1974) cite 0.01 mg/1 as a level of chlorine unlikely to cause stress to marine fish exposed intermittently. Thatcher (1978) conducted a series of bioassays to determine sensitivity to acute chlorine doses of 15 marine fish and invertebrates, at least two of which (pink salmon and Pacific sand lance) are reported in the Prudhoe Bay vicinity. He found 96-hr LC5o v a 1 ues for both of these species to be among the 1 owest of species tested (0.026-0.119 mg/1 total residual chlorine oxidation products). Amphipods (0.145 -0.687 mg/1 LC5o) and mysids (0.162 mg/1 LC5o) tested had somewhat lower sensitivities. Toxic concentrations ( 96-hr LC5o) of chlorine-induced products as low as 0.024-0.12 mg/1 were found for cr;ustacean larvae by Roberts (1978). Sublethal effects (reduction in respiration or egg production) have been observed in crustacean 1 arvae at chloramine concentrations of 0.02 -8.5 ppm and at chlorine concentrations of 0.01 -50.0 ppm (Capuzzo et. al. 1976), and in amphipods at chloramine concentrations of greater tnan 0.034 ppm (Arthur and Eaton 1971). Some synergi'st ic effects would be possible. Ammoni urn concentration and pH greatly affect the types and quantities of chlorination products . I 4-69 produced (Helz et al. 1978). In general, sensitivities of temperate species to chlorine are heightened by increasing acclimation temperature and by the combined action of exposure to chlorine and a thermal increment (Crumley et al. 1980). Extrapolation to arctic conditions is tenuous, but the thermal jncrement of the proposed discharge (1.1°C, 2°F during winter months) is well below increments that have been shown to elicit a heightened sensitivity to chlorine in other locations (e.g., Stober and Hansen 1974). However, persistence and accumulation of chlorine reaction products could be much greater under arctic conditions. Organisms subjected to mechanical stress by passage through the intake system probably would be more sensitive to chlorine and chlorination products than those used in the bioassay tests. (For purposes of impact analysis in this document, all entrained organisms have been considered killed.) The levels of chlorine reaction products present in the discharge at the edge of the mixing zone are calculated to be far below levels that are acutely toxic to marine organisms and below criteria designed to protect marine life (long-term exposure). Since the precise nature and quantity of these materials cannot be predicted, the potential for long-term accumulation (especially under ice) is unknown. However, some data are available from other areas. Fish from heavily industrialized and populated areas in Puget Sound that have received heavy doses of chlorine reaction products, PCBs, and a host of other po 11 utants have been demonstrated to have a somewhat higher incidence of disease than fish from nearby, less-polluted areas (Mal ins 1980). To date, there has been no indication of unusual human health problems resulting. Levels of pollutants in these areas are far greater than would result from the proposed project, even in the very localized area surrounding the discharge. Therefore, there would be no health threat to North Slope residents from these discharges. The 11 Ultimate sinks 11 of potentially toxic materials discharged from the Waterflood Project cannot be predicted (nor can they in the much-studied Puget Sound). No reasonable amount of laboratory or field study in other locations would allow prediction of these impacts with a high degree of confidence. Low levels of discharge and high dilution volumes suggest a relatively minor impact. However, it is known that many of these compounds can be concentrated many-fold in marine food webs. Therefore, it appears that, short of following the no action alter- native, the best way to determine the impacts of the proposed discharge would be through a monitoring program similar to that described in Chapter 5.0. If potentially harmful accumulations of chlorination products are seen in sediments or organisms outside of the mixing zone (including organisms that may feed within the mixing zone a portion of the time), then measures can be effectively taken to reduce or eliminate discharges. Although 0.01 ppm residual chlorine may cause a 50 percent inhibition in the photosynthetic activity of marine phytoplankton (Epply et al. 1976), this net effect would be minimal since only a small proportion of the area's phytoplankton standing stock would be affected, since discharge 4-70 velocities will carry entrained organisms to areas of lower concentra- tion, and since the reproductive capability of phytoplankters is great. This effect would be offset to some degree by nutrient enrichment resulting from the reduction of organic material washed from the filters. Some chlorination products, such as chlorinated phenols, may be toxic to kelp plants (Clendenning and North 1959). Addition of coagulant to the discharge stream wo~ld result in the discharge of coagulated solids. Available data are not sufficient to estimate the amount of residual coagulant, if any, that would be discharged. The primary effect of the discharge of any residual coagulant would probably be the continued coagulation of suspended solids at the point of discharge. The toxicity of the coagulant used should be low but should be tested during the operational monitoring program (Chapter 5.0). Larvae and spores of sessile organisms would probably settle on the intake structure and to a lesser extent on the outfall diffuser (Appendix E). These organisms, primarily filter feeders, would benefit from increased access to food and nutrients during operation of the seawater treating plant. Although this benefit would permit improved growth and reproductive rates, the population advantages would be doubtful since the eggs, larvae or spores released would usually be carried through the treating plant and treated with biocide. A related impact would arise during the winter period from the discharge temperature of l.loC (2°F) above the ambient water temperature (NPDES permit application). The heat~d effluent could increase the sculpturing of the ice sheet and consequently destroy substrate used by ice algae and associated organisms. The. magnitude of this effect would depend on the stability of the ice sheet and the variation in ambient currents. Since the portion of local ice algae populations affected would be extremely small and since the reproductive capabilities of these populations are high, no significant local or regional impacts would occur. Since the heated discharge would be rapidly cooled by mixing, diffusion, and contact with the ice, no significant adverse impacts to pelagic or benthic populations would be expected. Rapid cooling of the heated discharge (2 .9°C above ambient under winter conditions) with distance and mixing from the diffuser together with high discharge velocities would be unlikely to create a condition where organisms could be co 1 d-shocked by acclimation to discharge temperatures and sudden exposure to ambient temperatures. Aggregations of scavenging benthic invertebrates (e.g., Saduria, Boekosimus, Onismus) would probably develop near the main and marine life outfalls in response to the deposition of potential food. Di ss i pat ion of these potential food deposits by scavengers and wave action would be relatively rapid (probably within one open-water season), such that changes induced in organism distributions would not persist for a long period after discharges were terminated. 4-71 Scavenging and diving birds probably would be attracted to the outfall areas. Gulls and terns would be likely to feed on injured fish or other organisms. 01 dsquaw and other sea ducks might aggregate near the outfall in order to feed on concentrations of scavenging benthic invertebrates. These concentrations of birqs near causeway would be subjected to higher than normal hazards due to oil and fuel spills. During the open-water season, storm surges and wave act ion would probably transport suspended solids from the discharge. Moreover, consumption and scattering by scavengers (e.g., amphipods, isopods, mysids) that would probably aggregate near the discharge diffuser would slightly reduce the rate of accumulation. Epifaunal organisms in the Prudhoe Bay area typically have sufficient motility to avoid burial; infaunal organisms (e.g., polychaetes and the clam Cyrtodaria) would be most affected by sedimentation near the diffuser. The abilities of arctic infaunal animals to dig themselves out after burial are poorly known. During under-ice conditions, these animals may be in a low activity state, and thus may not be able to survive burial as well as during the open-water season. It seems unlikely that organic matter from the discharge would accumulate to the point where oxygen depletion in the sediments affected infaunal distributions beyond the effects due to burial. Since the density and diversity of benthic organisms generally increases with depth in this area (Feder et al. 1976a, Chin et al. 1979a), placing the main outfall diffuser in deeper water north of the island (as proposed) would potentially expose more marine life to the effluent than would the alternate location to the west of the causeway extension. However, this impact would be offset by a greater dilution of the effluent in the deeper water column under worst-case (under-ice) conditions. A "reasonable worst-case" scenario of the potential effect of the causeway extension and intake operation on anadromous fish was developed during a meeting of knowledgeable arctic scientists. A summary follows: Fish exiting the Colville River (primarily, least and arctic cisco; humpback and broad whitefish; some arctic char) disperse both eastward and westward {Figure 3 .9-1). It was assumed that 50 percent go in each direction. A further assumption was that, due to the distance from the mouth of the Colville to the causeway (70 km, 45 mi) only 75 percent of those heading east would reach the causeway {37.5 percent of the runs). This factor was also appl.ied to fish moving west from the Canning River. For the Sagavanirktok (primarily arctic char and broad whitefish) and the Kuparuk runs, it was assumed that a full 50 percent would reach, and presumably attempt to pass, the causeway. Increased migration distance (5 km, 3 mi) for two-way passage to get around the causeway extension was assumed to induce a mortality factor of 4 percent due to increased exposure to predation and possible reduced reproductive potential. (A migratior;~ distance of 125 km or 78 mi was assumed; 5 + 125 = 0.04.) 4-72 Intake system mortality of 14 percent was assumed (Appendix H). Because of the intake configuration and known surface orientation of several species, this was applied to 50 percent of eastbound fish and 20 percent of westbound fish presumed to enter the system. Thus, intake mortality would be 0.14 x 0.5 + 0.14 x 0.2 = 10 percent of fish passing the intake vicinity. The 15.2-m (50-ft) breach was assumed to allow 50 percent of the nearshore migrating fish (those most vulnerable to entrapment and intake mortality) to pass through the causeway. Thus, total mortality for Sagavanirktok and Kaparuk fish would be 0.5 (fish in area) x 0.04 · (migration loss) plus 0.5 (in area) x 0.1 (intake loss), with the entire figure reduced by 0.5 because of use of the breach. (0.5 x 0.04 + 0.5 x 0.1) x 0.5 = 0.035 o.r 3.5 percent For Canning and Colville fish, the calculation is~ (0.375 x 0.04 + 0.375 x 0.1) x 0.5 = 0.026 or 2.6 percent Use of the alternative 7 .6-m (25-ft) bypass was assumed to attract and pass only 20 percent of nearshore migrating fish through the causeway, thus increasing the above figures from 3.5 and 2.6 percent to 5.5 and 4 percent, respectively. Use of the alternative impinge/release type of intake system (Figure 2.5-SA) with a 30 percent mortality (vs 14 percent for the proposed system) would increase calculated reasonable worst- case mortality factors (assuming a 15.2-m bridge breach) to 6.3 and 4.7 percent, respectively. The reader must bear in mind that there is littl~ or no basis in field- observed facts for most of the numbers developed ·in this scenario. They represent a reasonable worst-case picture based on the best estimates and judgments of scientist~ knowledgeable in arctic fish populations and impact analysis. They are presented to evaluate the relative magnitude of potential impacts for a variety of alternative configurations. Some species of fish would be more likely than others to suffer mortalities as great as these figures. The generally large size and known surface orientation of the arctic char give it a low probability of suffering impacts this severe. Least ci sea have a high preference for nearshore waters and are abundant in the project vicinity; thus, they were assigned the greatest probability of suffering effects as great as those stated. Factors that may act to increase the projected adverse effects include the possibility that less than the assumed 50 percent of fish will use the proposed breach, or that ice blockage may stop passage during spring migrations. Also, currents passing through the breach might be an uncharacteristic element in the historic along- shore pathway taken by these species and inhibit their movement. Additionally, during some wind velocities, marine water with lower temperatures and higher salinity would penetrate far into the present shallow, warm, brackish water of the nearshore zone where migrating fish are normally concentrated; this could perhaps constitute a water quality block. In a similar line of reasoning, the 11 scent 11 from natal streams may be interrupted at times, thus reducing the probability of and 4-73 delaying homing. This latter effect is a more remote possibility, however. The population structure and behavior of some fish species may affect overall losses caused by the proposed project. For example, since adult female arctic char migrate in far greater numbers than males, their loss could constitute a loss of population reproductive capacity in excess of percentage of individuals lost. In this scenario, it has been assumed that reductions in fish populations due to any project-induced effects on Simpson Lagoon would be negligible. Other factors, however, may make the worst case less adverse. Migration losses of anadromous fish passing the causeway may be less than the assumed 4 percent, and the intake bypass and marine life return system may have less than a 14 percent mortality. Losses that do occur may be compensated for by increased survival or reproductive success in natal streams where competition for 1 imited spawning and overwintering sites is reduced by decreased densities. It has been reported that spawning and overwintering losses are density dependent. Thus, some portion of these hypothetical loss rates may be compensatory and the net effect. on run sizes may be less than that stated. Indeed, this balanced reasoning was an explicit process in establishing the scenario proposed. Alternative B (Gravel Island) The principal distinction between this alternative and the proposed alternative (A) with respect to operation is in the proposed locations of the outfalls and the location of the intake relative to man-made shorelines. The marine life return line would be located west, rather than east, of the treating plant and the main outfall line would be located north of the treating plant in 4.3 m {14 ft) of water. As a variation to this alternative, the main outfall line could be placed south of the island and terminate halfway to DH 3 in approximately 3 m (10 ft) of water. The major environmental consequences of this alternative, in comparison to the impacts of Alternative A, ~ould be: Reduced entrapment and bypass system trauma of anadromous fish. Possibly increased likelihood of recapturing organisms from the marine life return line in the intake structure. Separation of the intake location from the shoreline by approximately 1125 m {3700 ft) of open water would virtually eliminate entrapment of nearshore migrating anadromous salmonids and their subsequent loss due to impingement or entrainment. Large salmonids, especially arctic char, could still encounter the intake but would be better equipped to avoid harm. Because the less saline nearshore water would not be deflected to the intake vicinity, general water quality at the intake would be more marine. This could increase the numbers of marine fish (especially arctic cod) in the intake vicinity (cf. the proposed alternative). An 4-74 offshore structure may be behavori ally attractive to offshore fish. However, the concentrating effect of a causeway would not be factor. Since a causeway extension would not form a physical barrier between the marine life outfall and the intake structure in this alternative, organisms passing through this outfall, particularly those weakened by the experience, would be more susceptible to recapture by the intake structure. Such recapture probably would reduce their survival significantly. Since prevailing currents are from the east and north- east, placement of this outfall on the west side of the island would probably minimize the frequency of these recaptures. The requirement for on-island generation of power would create a greater level of noise and atmospheric emissions at the intake location than would the proposed location. A minor increase in disturbance to marine biota might result. Alternative C (Dredged Channel) Operation of the seawater treating plant under this alternative would differ from that under Alternative A in that: The dredged channe 1 would require rna i ntenance dredging. The marine life return outfall would be located in shallower water. The main outfall diffuser would be located in shallower water. The major adverse environmental impacts of this alternative, in addition to the impacts of Alternative A, would be: Destruction of benthic organisms and fish during maintenance dredging. ' Increased turbidity during maintenance dredging. Possible slight disruption of bird and mammal migrations due to noise produced by dredging activities. Probable increased intake of detritus and corresponding increased discharge during backwash. Probable increased mortality of organisms discharged through the marine life return line. Reduced mixing of effluent from the main outfall diffuser. The extent to which marine organisms would be destroyed by maintenance dredging depends on the frequency and amount of dredging required and on the degree of recolonization of the channel and spoil areas, and cannot be evaluated with the available information. Similarly, potential 4-75 impacts related to increased turbidity and noise strongly depend on the amount of dredging required. If filling from major storms during the open-water season is sufficient to require maintenance dredging each year, this dredging would prevent significant recolonization of the channel and spoil areas by sessile organisms during operation. The channel would function as a trap for detritus drifting along the sea floor and probably would funnel a significant portion of this captured detritus to the intake structure. This increased detritus intake and the generally poorer water quality in the DH 3 vicinity would require more frequent strainer and filter backwash and probably would require increased use of biocides and coagulants. Discharge of this material through the main outfall line probably would result, under conditions of easterly flow, in a small portion of it being recaptured by the channel and recycled through the treating plant. Organisms entrained in the intake stream would include many species characteristic of a relatively more diverse deeper water, higher salinity assemblage attracted shoreward by the dredged channel. Survivors would be discharged through the marine life return outfall into a relatively shallow, low salinity habitat to the east of DH 3. Particularly in winter, when this new habitat is greatly restricted vertically by shorefast ice, it probably would be unsuitable to many of these organisms. Since the main outfall diffuser would be located in shallower water (3m, 10 ft), dilution factors at the edge of the mixing zone would not meet State of Alaska water quality criteria under all conditions. Alternative Intake Design While it is not possible at this time to quantify the precise differ- ences in expected potential impacts due to alternative intake systems, adoption of the conventional impinge/release type of vertical travelling screen system (Appendix H) would greatly increase~ fish losses due to impingement. Using fine mesh screens on a centerflow-screen system together with the rapid impingement and release of fish larvae and juveniles could reduce entrainment and also reduce mortality up to 90 percent or more below that experienced by a conventional system for certain fish larvae, depending upon species, impingement duration, screen opening size, and velocities (Tomljanovich and Heuer 1979). Adult fish losses would still tend to be higher than with the angled screen fish guidance system. Using fine opening screens together with an angled screen fish guidance system (Figure 2.5-8b) can achieve comparable low levels of impact to 1 arval fish (Pavlov and Pakhorukov 1973) and should decrease potential adult mortality to an even greater extent. A lower velocity fish removal system {30.5 cm/s, 1 ft/s) would increase residence time in the return line up to about 6 min. This would increase the amount of time during which returned fish are subject to 4-76 the stress of the return system. Lower velocities would also increase the posibility of fish remaining in the system by maintaining themselves in the current until they become exhausted. Finally, lower velocities allow more biofouling by not scouring the return line. Accidents The probability of a system failure requ1r1ng evacuation of· the low-· pressure 1 ines has not been estimated. The effect of a total system failure most significant to the marine biota probably would be the discharge of biocide residuals, corrosion inhibitors (if in use), anti-foaming agents, vacuum pump lubricants, and the warmed deoxygenated water itself into marine waters. The potential impacts of such an accident have been assessed in Section 2.5, Applicant•s Proposed Project. A failure in the fish return system could also increase fish mortality. However, the applicant has stated that if system failures occur in any of the bays, the affected bay would be shut down and/or operations would be curtailed. The conventional travelling screen system is considered to be much more vulnerable to malfunction than the proposed angled screen system under arctic conditions. FRESHWATER RESOURCES Construction Impacts Alternative A (Proposed by Applicant) The onshore waterflood facilities, with the exception of a Kuparuk River pipeline crossing, will not directly conflict with lakes or streams; therefore, impacts on these resources are expected to be minor. Potential direct and indirect impacts are described below. High-and low-pressure pipeline crossings of minor streams would be elevated and the crossing of the Sagavanirktok River would be on the existing bridge. Little or no impact on the freshwater environment wou 1 d occur from these eros sings. However, the high-pres sure pipe 1 i ne to Pad S would be buried across the Kuparuk River. Construction of this pipeline would involve instream work and, consequently, would disrupt the stream bottom at the crossing site. If there were stream flow during construction, the activity would increase suspended sol ids concentrations and cause downstream sediment deposition. Impacts, if any, to resident fish populations would depend on the time of the year. Current plans call for construction to occur during the winter in conjunction with proposed oil pipelines between Pad M and Pad S. Bendock (1979) found at least two fish overwintering areas downstream from the proposed crossing, one of which was within 1 km (0.6 mi). It is not known whether continuous stream flow exists in winter between the crossing area and the overwintering area. If continuous flow does exist, construction of a buried crossing could have significant adverse effects on downstream over-wintering fish due to increased oxygen demand and silt deposition. On the other hand, if no flow exists in the crossing area, little impact on fish resources would result. 4-77 Alterations in surface drainage patterns due to road and work con- struction could affect water levels and water quality downstream. Drainage control procedures would minimize these potential impacts. Fill placement in wet areas would create short-term erosion-like conditions. Waters adjacent to the fill would have higher suspended solids concentrations and be more turbid. Probable concomitant effects include reduced light penetration, temperature increases, reduced dissolved oxygen levels, and a possible increase in nutrients. These impacts would be localized along filled areas and continue until the fill is stabilized. Spring breakup would act as a flushing agent and negate these impacts. Dust fallout onto ponds and 1 akes adjacent to construct ion areas may increase productivity by adding nutrients to the water (Alexander and Miller 1977). Subsequent subtle effects on pond fauna may occur. The greatest zone of impact would probably occur within 100 m (330 ft) of the actiyity. The proposed gravel sites are totally isolated from adjacent streams, and are not within the active floodplain. No impacts on streams are anticipated from continued mining of these sites, assuming that existing controls are maintained. The ultimate impact on the freshwater environment would depend on final restoration plans. The creation of several isolated deep lakes is a probable outcome. Proper planning may enhance fish habitat in the area. In the event that government agencies permit the taking of gravel from floodplains, the degree of impact would depend on the type (scraping vs pits) and location of mining. Physical changes that could occur include changes to stream length, pool-riffle ration, substrate, alluvial ground water, and water velocity, gradient, width, and depth. Other 1 ikely changes could occur in the sediment regime from flooding and subsequent pending, flow obstructions, intergravel flow, and aufeis development. Biological effects could include alteration of fish spawning and ove~­ wintering habitat through siltation or chemical disruption, reduced stream productivity, and stranding of fish. Most of these impacts are avoida~le through proper planning. This project would add about 900 construction workers to the PBU population at the height of construction. These workers would use about 320 m3fd (84,000 gal/d) of fresh water and three drill rigs would use another 430 m3fd (114,000 gal/d). This amounts to 750 m3fd (200,000 gal/d) in addition to the present 3030 m3/d (800,00 gal/d) usage. With approximately 3780 m3fd (1 million gal/d) of water being used, and assuming an 8.5-month winter storage period, the reservoirs would have to contain at least 980,000 m3 (260 million gal) to provide water through the winter. This is less than 40 percent of the present reservoir capacity (2.6 million m3, 700 million gal). Small operators commonly transfer water from reservoirs to storage tanks with tank 4-78 , trucks when, and if, their storage tanks become low. The 1 arge operators, ARCO and Sohio, have sufficient storage for their base camps. In past years, winter water availability has been low and water was withdrawn from under the ice in the Sagavanirktok and Kuparuk Rivers, causing adverse impacts to overwintering fish populations. Recent development of water reservoirs, expanded use of lake water, and careful planning have eliminated the earlier problems. Future impacts on fish due to domestic water withdrawal are not anticipated within the context of current regulations and improved long-term planning (Bendock 1979). Demands on facilities for handling domestic solid and liquid wastes would increase during the peak of construction. Existing and planned facilities have sufficient .capability to handle the increased loads (Bateman 1979, FERC 1979). Cumulative impacts on freshwater resources would be minimal within the context of current regulations and improved long-term planning. Spills or leaks of petroleum products reaching fresh water would cause some water quality degradation. The ultimate impact will depend on the type of product, location, volume, season, and duration of spill or leak, and the timeliness and effectiveness of containment and cleanup operations. Leaching of che~icals or other pollutants from drilling mud and cuttings is possible. This may adversely affect surrounding tundra and water quality. Alternative Designs and Con{igurations Most of the design altern a~ ives discussed for the Waterflood Project waul d not adverse 1 y impact the freshwater environment. However, the alternative routing of the west low-pressure pipeline along the existing east road would eliminate a substantial amount of terrain disturbance. Potential impacts on the freshwater environment, resulting from alteration in drainage patterns and dust deposition, would be alleviated. If alternative material sources within active river floodplains should be used, impacts on the freshwater environment would be substantially increased. Operation Impacts Alternative A (Proposed by Applicant) Operation of waterflood facilities would cause an increase in the cumulative traffic level and thus waul d increase the long-term dust fallout by a proportion ate amount. Operation impacts on freshwater resources would be as discussed for construction. The operations phase would require the addition of less than 100 persons to the permanent PBU population. These people would use 3.0 -3.4 m3jd {800-900 gal/d) of water, and would not stress the available freshwater supply. 4-79 Cumulative adverse impacts to water availability assoei ated with the Waterflood Project as well as development of other projects (SGCF, gas line, Kuparuk field, and Beaufort Sea lease sale) appear to be unlikely. Water use associated with Beaufort Sea development wi 11 peak at 227,000 m3 (60 million gal) in 1989, and gradua.lly reduce until 1999 and 2000 when water use will be 23,000 m3 (6 million gal) (BLM 1979). At worst, assuming all 227,000 m3 (625 m3Jd, 165,000 gal /d) is taken from the PBU area, about 60,000 m3 (42 million gal) would be used over the critical winter period. This amounts to about 6 percent of the present winter storage capacity. If a break or leak in the low-or high-pressure pipelines should occur, quantities of saltwater in excess of 5000 m3 (1 million gal) could enter lakes, ponds, or streams depending on leak location and time of year. Lake and pond water quality is generally characterized by low salt levels (except adjacent to the coast); therefore, substantial changes in water chemistry could occur following a spi 11. Effects on the ecological community are difficult to predict and would depend on the dilution factor (Section 4.2, Vegetation and Terrestrial Wildlife). The common emergent sedges and grasses are probably tolerant of saline conditions judging from their wide distribution in the area. Phyto- plankton, along with micro-and macroinvertebrates, are likely to be more sensitive to water chemistry changes. Long-term community alterations could result. The freshwater communities would be most sensitive to saltwater spills during the later part of the growing season when dilution and flushing would be minimal. The effects of such a spi 11 on water quality would 1 ast at least until spring breakup when runoff would dilute and flush the seawater. More than one breakup period may be required to restore natural water quality in the event a large spill became concentrated in a small area. Alternative Designs and Configuration Most of the design alternatives discussed for the Waterflood Project would not impact the freshwater environment. However, the alternative routing of the west low-pressure pipeline along the existing east road would e 1 iminate long-term impacts on the freshwater environment resulting from alteration in drainage patterns and dust deposition. GROUNDWATER RESOURCES Construction and Operation Impacts This project would have negligible adverse impacts on the groundwater resources; no impact on subpermafrost and intrapermafrost ground water, and minor impact on suprapermafrost ground water. Groundwater quality would display little, if any, decrease owing to fill placement for roads and pads. No direct impacts on suprapermafrost ground water are anticipated; however, one indirect impact would occur. 4-80 The permafrost table would rise under roads and pads, with the potential to dam lateral movement of ground water in the active layer. Where this occurs water would gradually accumulate at the surface and result in ponding. Recent studies have identified the significanGe and degree of ponding from existing gravel fill in the Prudhoe Bay area (Davidson in press). Ponding would have immediate direct impacts on the biological use of the land ponded. These impacts may be positive or negative depending on the species and its habitat needs.· In the long-term, ponds may eventually evolve into thaw lakes and result in thaw instability of the soils supporting nearby roads and pads. Gravel extraction would have insignificant impacts on ground water. Since 1976, North Slope resource managers have avoided permitting gravel extract ion in active floodplains. Therefore, gravel would be obtained from established upland material sites. These sites are surrounded by permafrost, which effectively isolates potential impacts resulting from gravel removal. Some contamination of suprapermafrost ground water may occur near effluent holding ponds and in areas where effluent is discharged to the tundra surface. (Effluent discharge to the tundra surface is approved by th~ Alaska Department of Environmental Conservation.) The impacts of 1 andfi 11 operation on ground\Vater resources would be minimal. The NSB sanitary landfill, anticipated to open in summer 1980, is expected to be properly designed and operated to minimize potential adverse impacts. Permafrost will effectivel;Y isolate the landfill. Spills or 1 eaks of petro 1 eum ·products used , during construct ion and operation could adversely impact groundwat~r quality. Accidental discharge of seawater from the low or high-pressure pipelines could also affect the groundwater resource. The potential for adverse impact from these accidents would be minimal when the active layer is frozen because the spilled material would not enter the groundwater aquifer. Spring breakup would dilute and flush the spilled material, if not contained and cleaned up, to lakes and ponas, streams, or the Beaufort Sea. Some adverse impact to groundwater quality would occur if spills occur when the active layer is thawed. METEOROLOGY AND AIR QUALITY Construction Impacts Construction impacts on air quality would consist mainly of the rela- tively minor amounts of pollutants emitted from the heavy construct ion equipment required for site preparation and from fugitive dust emissions associated with gravel operations. Exhaust emissions from construct ion equipment would cause only localized, temporary effects upon existing air quality with no adverse impacts beyond the project area. 4-81 Fugitive dust emissions are expected to be the most noticeable impact during construct ion. The amount of dust would vary with the 1 evel of activity and the weather. Overall, fugitive dust should add only minimally to existing background particulate levels in the area. Operation Impacts Emissions Air pollutant emissions from the project facilities would be produced by approximately ten gas-fired heaters totaling 650 mi 11 ion Btu/hr and approximately nine gas-fired turbines totaling 160,000 hp. The heaters would be required at the seawater treating p 1 ant and the inject ion plants to prevent freezing in the pipeline distribution system and to provide emergency heat when heat recovery from the turbines is not possible. The turbines would provide the power necessary for pumping at the injection plants. These sources would have total potential emissions as follows: TSP - 130 tons/yr, S02 - 5 tons/yr, CO -823 tons/yr, NOx -4674 tons/yr, and HC -149 tons/yr. These emissions would contribute only a small increment to the present emissions in the Prudhoe Bay area. A more detailed breakdown of these emissions is given in the PSD application. Air Quality Review-PSD The air quality impact of the waterflood sources a lone can be assessed in terms of Prevent ion of Significant Deterioration ( PSD) regulations that were mandated by the Clean Air Act Amendments of 1977. The Act established increments to prevent the deterioration of existing air quality and, hence, to protect environmental and human health. The project area is an attainment Class II area for all EPA criteria pollutants. The results of the PSD impact analyses showed that no PSD increments would be exceeded as a result of emissions from waterflood facilities. The only pollutants for which PSD increments have been established are TSP and S02, both of which would be far below the allowable increment in a Class II area. The predicted levels also are far below 11 significance 11 levels as determined by EPA (Table 4.2-6). These 11 Significance" levels are at or below Class I (as well as Class II) maximum allowable increments. Air Quality Review-NAAQS The cumulative air quality impacts of the waterflood sources, existing sources, and other proposed sources can be assessed in terms of National Ambient Air Quality Standards (NAAQS). These standards apply to the same criteria pollutants discussed under PSD regulations above. The Clean Air Act Amendments of 1977 and accompanying PSD regulations mandated that new sources of air pollution would review the air quality impact of their emissions with respect to NAAQS as well as PSD 4-82 TABLE 4.2-6 SUMMARY OF PSD INCREMENT COMPLIANCE FOR THE WATERFLOOD FACILITIES (J.Jgfm3) so 2 TSP Annual 24-Hour 3-Hour Annual 24-Hour Class II Maximum Allowable Increment 20 91 512 19 37 Class I Maximum Allowable Increment 2 5 25 5 10 Predicted Consumption of Waterflood Facilities 0.1 0.3 Total PSD Increment Consumption of All Fac i 1 it i es 0.3 2.4 Significance Loads(1) 1 5 25 1 5 (1)source: Federal Register 43, No. 118, p. 26398. 4-83 increments. The consumption of PSD increments is never allowed to exceed NAAQS, which are designed to protect public health and welfare. Public health is protected by the primary standard, while the secondary standard protects the public welfare (property, plants, animals, housing, etc.). There have been three PSD applications for new sources in the PBU (Dames & Moore 1978a; Radian 1979a, b). The last of these three applications was for the Waterflood Project. In addition, there is one proposed source in the project area for which no PSD application has been made, namely the sales gas conditioning facility (SGCF}. However, a DEIS was prepared for the SGCF in which an air quality analysis is given (FERC 1979). Altogether then, there are three proposed new sources in the project area, the impacts of which must be added to the proposed Waterflood Project impacts and the existing source impacts in order to assess cumulative air quality impacts. Existing sources impacts were first analyzed in the first PSD applica- tion (Dames & Moore 1978a). At that time, limited monitoring data existed for Prudhoe Bay. An air quality monitoring program was started in 1979, however, and approximately 6.5 months of data were reported by the PBU owners in the waterflood PSD application (Radian 1979b). Estimated background levels for PSD, S02, CO, N02, 03, and NMHC were also given in the PSD application (Table 4.2-7). Table 4.2-7 also presents the impacts of all four proposed sources for EPA's criteria pollutants, the cumulative impacts, and the NAAQS. Considering the fact that the dispersion modeling approach used for all the proposed sources was conservative (Dames & Moore 1978a; Radian 1979a,b; FERC 1979}, the cumulative impacts shown in Table 4.2-7 are low, especially when compared to NAAQS. Furthermore, it can be concluded that there will be no significant adverse impacts from air pollution emissions since these levels are well below the NAAQS. The two largest actual emissions from the project would be carbon monoxide and nitrogen uxides. The impacts of these on soils and vegetation, including lichens, are discussed in the PSD permit appli- cation. The impact on soil was determined to be,insignificant, and the concentrations of carbon monoxide and nitrogen ox ides were considered to be far below levels having detrimental effects on vegetation and wildlife. Alternatives The gravel island alternative would require on-site generation of eleCtrical power. This additional source would increase emissions in the water treating plant vicinity. 4-84 TABLE 4.2-7 CUMULATIVE AIR QUALITY IMPACTS PRUDHOE BAY~ ALASKA (JJgfm3) Maximum Averaging Background Existing 1st 2nd Cumulative Pollutant Period Level Sources PSD PSD Waterflood SGCF Impact (b) NAAQs(c) - TSP Annual 9 5 1 1 1 1 18 60 24-hr 9 79 1 4 4 8 106 150 ~ so 2 Annual 0 1 (a) (a) (a) 1 2 80 I 24-hr 0 10 (a) (a) (a) 3 22 265 00 <.11 3-hr 0 18 (a) (a) (a) 5 23 1,300 co 8-hr 180 926 283 (a) (a) (a) 1,389 10,000 1-h4 180 3,160 283 (a) (a) (a) 3,6,23 40,000 N02 Annual 1 23 1 3 5 20 57 100 03 1-hr 56 57 (a) (a) (a) (a) 113 240 - (a) Not modeled (b) Unlikely to occur as maximums for existing and proposed sources have not coincided in any modeling studies to date. (c) Most stringent of primary or secondary. SOUND Construction Impacts The proposed facilities require constructing a seawater treating plant, injection plants, an expanded and extended causeway, a modified dockhead and numerous pipelines. Typical noise-producing construction activities would include the following: Extraction and placement of gravel. Installation of sheetpile bulkheads and anchorpiles. Dredging of the slip for placement of gravel foundations for the seawater treating plant. Installation of pile bents and construction of pipeline. Dredging of the slip for placement of gravel foundations for the seawater treating plant. Installation of pile bents and construction of pipeline. Sealifting or trucking of pipeline and equipment and erection of module units. The noisiest periods of construction would occur during gravel placement and grading, pipeline construction, and module placement (Table 4.2-8). The construction equipment required during these phases and their equivalent sound leve·ls at 15 m {50 ft) are presented in Appendix G. The equivalent sound level (Leg) during gravel placement and grading operations is estimated to be 89 decibles (dB) at 15 m from the center of activity. A maximum sound level of 98 dB at 15 m is estimated under worst-case conditions of simultaneous equipment operation. This phase of construction would increase the ambient sound level within several thousand meters. Placement of the treating plant and unloading of module units would result in an equivalent sound level of 92 dB at 15 m fro~ the center of activity. The construction ambient sound level at each measurement location is determined from the construction noise level and the measured background ambient sound level. Examination of day-night equivalent sound levels indicates a substantial decrease in ambient sound level within 60 m (200 ft) of construction. Operation Impacts The major noise sources associated with operation of the Waterflood Project would include: (1) backwash, transfer, and circulating pumps, heat exchangers, and heaters of the seawater treating plant; and (2) injection pumps, gas turbines, heaters, and emergency generator units at 4-86 the east and west injection plants. Major noise sources at the injection well pads would include standby heaters, displacement and circulation pumps, air compressors, and emergency generator units. Sound levels emitted by the proposed facilities were estimated from sound measurements at the site (FERC 1979) and from published data on equipment noise (Dames & Moore 1979, Seebold 1973, Teplitzky 1976; Tatge 1973, and Bush 1977). Maximum sound level contributions are anticipated to be through turbine air intakes, heater units, generators, and heater exhausts. Since equipment would be enclosed within module housing, sound radiating from pumps, air compressors and other equipment would be attenuated. Heat recovery equipment and silencers would provide additional attenuation. To estimate daytime equivalent sound levels, each contribution was added on an energy basis and combined with background ambient sound 1 evel s. Estimated sound level contributions of all major facilities are as follows: Facility Seawater Treating Plant East & West Injection Plants Injection Site Facilities High Pressure Pipelines Equivalent Sound Level (Leq) in dB @ 15 m (50 ft) 80 80 78 55 Examination of the day-night sound levels indicates an increase of less than 6 dB at all measurement sites. Impact Assessment Possible effects of noise on wildlife include interference with communication resulting in secondary effects on (1) navigation, (2) reproduction potential, (3) maintenance or establishment of contact with other group members, and (4) conveyance of messages such as distress or danger, presence of food and extent of territory. However, the ability to relate noise levels to impacts on marine mammals, birds, and other wildlife in the project area is difficult due to lack of published data. Marine mammals produce a variety of sounds and can perceive underwater signals below 500 Hz (cycles per second) as well as a variety of . airborne sounds (Myrberg 1978). An increase in ambient noise at low frequencies has a greater effect on audibility than a similar increase at high frequencies. Ship traffic, wind, soniferous marine animals, construction activities, and operational activities all contribute at frequencies within this range. Since marine mammals' hearing 4-87 abilities cover a broad frequency range, sound interference may actually pose little problem to them (Myrberg 1978). Most can use some form of signal processing so as to perceive specific signals even at low amplitudes. Studies by Andersen (1970) and Mohl (1968) confirm that marine mammals demonstrate extremely high sensitivity to a wide range of high frequency sounds with an extremely rapid cut-off in sensitivity at their upper hearing limits. Extreme high frequencies are seldom affected by environmental or construction noises such as those anticipated in this project. Due to the rarity of bowheads and other whales recorded in the project area, noise impacts on these species are expected to be negligible. Movement of barges to and from Prudhoe Bay would not coincide with migrations of bowhead whales (Section 4.2, Marine Biology). Noise impacts on fish are anticipated to be minimal. Noise impacts on birds have been discussed under Section 4.2, Vegetation and Terrestrial Wildlife, and Wetlands. Post-calving concentrations of caribou use coastal zones, beaches, and spits for relief from insects from late June to August. Caribou have been observed throughout the Prudhoe Bay area during the exploration, development, and production phases of the field. Cameron and Whitten (1979) determined that cumulative disturbance in the area has caused a portion of the herd (designated the "Central Arctic" herd), especially females and calves, to abandon the oil field. Because construction noise does disturb caribou during their summer activites and reduce their habitat, it is possible that caribou use of the area would decline during some portion of the season. The extent of this decline is unknown. Caribou are also reported to move away from noise sources including both low flying fixed and rotary-wing aircraft (McCourt et al. 1972, Reynolds 1974). Such activities, if concentrated, could permanently displace the animals from some areas and effectively eliminate those areas from the caribou • s use. Cumulative construction and operation noise contributions are anticipated to have the most significant effect on ~he area•s wildlife. Construction and operational noises are not anticipated to result in any impacts to humans. The gravel island alternative would require on-site generation of electrical power with associated increase in noise level over the life of the project. A minor disruption of distribution of marine species, primarily birds and mammals, would result. 4-88 SOCIOECONOMIC EFFECTS Construction Impacts Population and Employment Estimated manpower requirements for field work are shown in Figure 2.5-16. Incremental population increase on the North Slope would equal this employment minus local residents who are hired. There would be no direct secondary employment or population increase attributable to the primary workforce because workmen would 1 ive in dormitories without their families, and be supported from ~utside the region. However, any increase in activity at or near Prudhoe Bay concomitantly causes increased focus on the entire North Slope. Many of those who find their way to Barrow are, in fact, seeking work at Prudhoe Bay in hope thAt the geographic proximity of Barrow and the local employment opportunities will afford them an increased opportunity to work at Prudhoe Bay. This method of seeking work at PBU may be increased as ASRC and village corporation ventures secure contracts or subcontracts to perform at or in relation to the PBU. The extent to which local people would work on the project is unknown. The PBU owners· do not plan to establish a perferential native-hire program specific to the Waterflood Project in addition to standard Equal Employment Opportunities and Minority Business Enterprises programs now in operation (Section 2.5, Applicant's Proposed Project). Existing informal recruiting of borough residents would be continued and expanded. The effectiveness· of these 1 atter programs may depend upon skill requirements and union control. Particularly where union activities are concerned, hiring tends to be done outside of the area and often outside of the state. The Tribal Employment Rights Office of !CAS may be a potential source of securing concessions to local hiring and training of Inupi at as a part of the 1 abor force at the PBU and petroleum activities elsewhere within the North Slope Borough. Existing facilities and housing in the Prudhoe Bay/Deadhorse area are sufficient to accommodate the project workforce, even if construction of the sales gas conditioning plant and gas pipeline occurs simultaneously. At the peak of oil field development and oil pipeline construction in the summer of 1976, over 8880 people were working on the North Slope. Currently, about 3000 people at Prudhoe Bay are engaged in operation, continuing field development and production drilling. If this number remains stable, and the waterflood, gas conditioning, and gas pipeline projects coincide, the combined( )1 abor force requirement should not exceed the previous peak of 8800. 1 (!)Peak labor force requirements of the sales gas conditioning plant are estimated at approximately 1000 (FERC 1979). Exact estimates of gas pipeline construction 1 abor requirements are not available. 4-89 At the statewide level, the project would result in a small, but significant, temporary increase in population and employment. This increase cannot be estimated in quantitative terms at the present time, however, because several factors are unknown. For example, incremental short-term population growth would depend in large measure on the extent to which requirements would be met from the Alaska workforce. This in turn waul d depend upon the 1 abor market demand at the time of con- struction: if other major projects are underway simultaneously, such as the Alpetco refinery in Valdez, the sales gas conditioning plant, and the gas pipeline, a much 1 arger proportion of the 1 abor requirements would be met with non-resident labor. Also, the magnitude of secondary employment and population impacts would depend upon the number of non-resident workers, as well as the value of goods and services purchased by the project owners and execution contractors. Although project planning has not reached the point where in-state purchases of goods and non-labor services can be identified or estimated in quantitative terms, the project would have a positive impact on the economies of Anchorage and Fairbanks during 'the construction phase. The bulk of project material would be shipped by barge to the North Slope from manufacturing and staging areas outside of Alaska. Nonetheless, there would be substantial demand in Alaska for surface and air traosportation services for miscellaneous project supplies and equipment and for personnel. The retail sector, including restaurants and hotels, waul d benefit from the flow of project-associated personnel through Anchorage and Fairbanks. Alaska-based firms could be expected to obtain important prime and subcontracts for civil and structural work. Because the economies of Fairbanks and Anchorage have ·considerable excess capacity, no adverse economic impacts are foreseen, even if the project coincides with other major construction work in the State. Pub 1 ic Finance No significant pub 1 ic fi seal impacts on the North Slope Borough are expected during· either the construction or operational phase. The project could generate modest tax revenue to the State during the construction period under the statewide property tax on certain oil and gas property (AS 43.56). If the project were 50 percent complete on January 1, 1984, it would generate approximately $20 million in property tax revenue to the State ($2 billion x 50 percent x 20 mills= $20 million). Tax revenue generated by the facility does not necessarily represent net impact to the State, however, because the State government may have to provide public services to the incoming population. While it is not possible to quantitfy these public costs, they should be comparatively small compared to revenues. 4-90 Archaeological Features The recent edition of the National Register of Historic Places and its supplements have been consulted, and a reconnaissance survey of potentially affected areas has been conducted. It is concluded that the proposed action would have no effect on resources of significance. The State Historic Preservation Officer has concurred in these findings. Navigation The causeway extension would constitute an obstruction to navigation and require alteration of the course of vessels traveling between Simpson Lagoon and Prudhoe Bay. Most of these vessels would be involved in oil industry activities, although some may be engaged in scientific, recreational, or subsistence activities. The gravel island alternative would constitute less of an obstruction to navigation. A slight potential for damage to the buried pipelines to the island would exist, either from vessels dragging anchor or from vessel groundings. Operation Impacts Population and Employment The faci 1 ity is estimated to require a total workforce of 280 -330 (rotation of 7 days on, 7 days off). It is unlikely that many of the operating personnel would be No~th Slope residents. Direct statewide population and employment impacts of the project would be insignificant. The potential impact of the project on the State economy would be through the expenditure of tax revenues. Pub 1 i c Finance Because the NSB has already reached the 1 imit of property tax revenue for general operating purposes allowed by State law (the 30-mill limit in AS 29.53.050[a] and the maximum allowable under the formula in AS 29.53.040[c]), and because the Waterflood Project will not increase population of the borough under new U.S. census procedures, the project will not significantly increase borough general property tax income for operating purposes. The project would add $2 bi 11 ion to the assessed value of the NSB, an increase of 39 percent over the current value of $5.106 billion. If the borough does not increase its bonded indebtedness, the effect of this increase in the tax base would be to lower the borough land levy. However, to the extent that the owners of the Waterflood Project are the owners of oi 1-rel ated property at Prudhoe Bay that now constitutes 98 percent of the borough's tax base, there would not be tax relief from 4-91 a 1 ower mi 11 age rate. That is, tot a 1 tax revenue required to meet existing debt service of the borough would remain the same (assuming no further bonding) even with a lower millage rate and more property available to share the tax. The incremental assessed value of NSB property represented by the waterflood facilities will not affect revenues of the borough used to retire outstanding bonded debt. In the long run, this incremental value may enhance the abi 1 ity of the borough to se 11 future bond issues by lowering the ratio of net general obligation bonded debt to assessed value. Increased State public revenue is a very significant statewide impact of the Waterflood Project. Incremental production revenue (royalities and severance taxes) is estimated at between $9.4 billion and $26 billion over the life of the project. In addition to increased production revenue, the Waterflood Project would generate approximately $40 million annually in State property tax revenue, or some $800 mill ion over the 20-year 1 ife of the project. Sociocultural Conditions . Urban life-style throughout Alaska is not expected to be impacted except for increased activity in the economic sector, particularly in Fairbanks and Anchorage. Increased State revenues may support additional social service programs such as the· arts, construct ion of rura 1 schools, power generation facilities, transportation infrastructure, and increase reliabiilty of same where it exists, which in turn affects local, regional, and statewide social frameworks. In a cultural sense, construction and operation of the project would have no measurable impact on the North Slope. In assessing cultura 1 impact on the North Slope several parameters were used as indicators of change, namely fish, wildlife, and habitat, since they constitute the foundation of subsistence 1 ifestyle. Estimated losses of fish species traditionally harvested were calculated from the reasonable worst-case scenario (Section 4.2, Marine Biology). Losses for the village of Nuiqsut would amount to less than 3 percent of the harvestab·le resource, while the village of Kaktovik would suffer losses amounting to less than 1 percent. Direct potentia 1 effects on caribou, marine mamma 1 s, and waterfowl would be negligible to the subsistence harvest. Cumulatively, this project would advance the continuum of change on the North Slope another increment. Sect ion 3.15 discusses possible future activity in the immediate region between the Canning and Colville Rivers, across the American Arctic, and in the Canadian Beaufort Sea. These activities, coupled with other agents of change past, present, and future (e.g., improved transportation by air and ground, increasing political and economic structure, improved communication systems, etc.) act together to stress the traditional Inupi at culture (see Sect ions 3.2, 3.14, and 4.1). 4-92 Negative impacts from events of the past few years, as viewed by members of the North Slope communities, include: Dead fish in the Kuparuk River, Colville River, and Sagavanirtok River, as well as in the ocean inside the Barrier Islands Oily tasting fish in the Colville and Kuparuk Rivers Increased competition and negative feelings between villagers in Nuiqsut and a commercial fishery in the Colville Delta Restricted access to traditional fishery and camping sites east of Prudhoe Bay by the community of Kaktovik Increased pressure on subsistence fishing and hunting as a result of Federal and State surveillance and regulations Increased and potential increases in competition with recre- ational and other non-consumptive users of fish and game resources Increased costs of fuel oil, freight and food from village stores, with a concomitant fluctuation in village cash economies resulting from NSB capital improvement project completion, particularly major projects like housing and schools. The current high-wage cash economy in the villages is not a permanent fixture. At some point in the near future (and the present for several months out of the year) sources of cash that are necessary to support villagers in both their subsistence enterprises and in their homes and communities may once again be from external sources such as outside labor, and subsidy programs from Federal and State sources. Incremental changes of habitat and animal populations from cumulative developments (Section 3.15) could result in reduced access to and availability of certain subsistence resources. Reduction in these resources, rapid development of the PBU, and little assurance of either employment opportunity or alternative resources may increase stress within the traditional community. Real and potential threats to the subsistence economy and to the necessary supportive cash economy are magnified in other areas of community functioning, particularly at the personal and family levels. These threats to the core of Inupiat culture and community are often manifested in both intra-and extra- ethnic hostility. Expected results of over-stressing individuals and communities are alcohol and drug abuse, violence, and family disruption resulting in loss of a sense of community. It is important to note that oil development in the Arctic has and will bring a relatively new source of change and anxiety for the Inupiat. 4-93 This is related to physical and biological changes in habitat, hunting range, and the related effects on subsistence species. Most change factors in the past were related to new institutions and new contact with different cultures. The Inupiat have a relatively brief exposure to events that have implications for large-scale changes in the environment. On a positive note, increased opportunity for the exercise of Inupi at controlled and/or owned institutions cou 1 d result in increased fam- iliarity and comfort with industry . If successful, the role of village and regional corporation businesses may provide a culturally and socially acceptable work milieu in which necessary cash can be earned without:;totally jeopardizing subsistence skills and opportunities. The Inupiat;J particularly community leaders, may have an opportunity to work closeli~'with industry. That experience could be of great assistance in dealing ~:with similar circumstances and projects that will surely occur in the :future. The Inupiat people and culture have shown their ability to adapt to changing situations while retaining the essential elements of their society. 4-94 < ·•. 't' \ I CHAPTER 5.0 POTENTIAL MONITORING PROGRAMS AND PERMIT CONSTRAINTS The proposed project is a camp 1 ex and, to some extent, unprecedented undertaking. Indeed, the project constitutes one of the first permanent engineering works of significant magnitude to be proposed for construction and operation in the Arctic Ocean. Furthermore, it can be viewed as representing the first of similar future proposals coming under public regulatory review in the United States. A considerable amount of public and industry interest thus exists to document project effects and to evaluate project operational performance. Two discrete goals exist for such monitoring. The first relates to improving impact prediction accuracy for future proposals. With proper scientific observation, the need to apply required 11 Worst-case 11 scenarios would be considerably diminished, the reason for controversy lessened, and the regulatory process made more predictable. The second goal is to have information about project environmental performance while in operation. This would allow adjustments to be made in oper- ation and provide the basis for design changes to be considered that waul d insure regulatory requirements being met or improvements made. A wide variety of monitoring programs could be conceived to evaluate and document project performance and impacts. Specific programs will be selected on the basis of need to ensure compliance with NPDES, PSD, and Corps of Engineers• permit conditions. Other agencies, the applicant, or academic interests may wish to pursue other monitoring or imp~ct evaluation studies. As the EIS process has proceeded, the applicant has altered the proposed action to incorporate a number of additional or modified design features intended to reduce the environ- mental impact of the project. Other mitigative measures may be required by permit conditions (see Section 5.4). Some obvious areas of overlap would occur between categories in any comprehensive monitoring program. For example, monitoring certain aspects of ambient water quality would be a necessary part of water treating plant operating data and provide data important on a regional basis. Water quality alterations induced by the proposed causeway extension also should be evaluated and documented. The duration of studies to meet various objectives may vary considerably. For example, the first two types of water quality monitoring might continue for the life of the project, whereas the effects of the proposed causeway extension on water quality would be resolved after only 1 or 2 years of study. Programs described should be analyzed after implementation and revised as deemed appropriate to better address issues at hand or discontinued if no useful information is gained. Many of the studies outlined in this section would necessitate establishment of precon- struction or preoperation baseline conditions in a scientifically acceptable manner such that project effects can be reliably estimated. 5-1 Programs presented in Section 5.1 are representative of those that the applicant may wish to institute to evaluate engineering performance of the project. The specific requirements of the Corps and other agencies are expected to be similar to those presented in Sections 5.2 and 5.3. A summary of a comprehensive monitoring program designed to satisfy all anticipated needs is provided in Table 5.0-1. For each program, the type of requirement satisfied (e.g., engineering and operational, permit compliance, broadening scientific knowledge), duration, monitoring frequency and brief methodology are provided. It should be noted that while the methods, timing, and other information in Table 5.0-1 are quite specific in some instances, it is to be considered preliminary. If a permit is granted and upon study approval, a more detailed study plan will be prepared that will, at a minimum, provide coverage as specified in the study category. Every two years after issuance of permits for this project (or more often if deemed appropriate), a technical review of the results of monitoring programs required by the permits will be conducted. The result of this review will be a recommendation to continue, modify, or delete each element. To maximize the information and degree of environmental protection derived from the studies, a coordinated, interdisciplinary approach under the direction of a single agency or entity is needed. The Corps, in cooperation with other agencies and the applicant, is currently pursuing various management proposals. Information gathered in· studies performed to evaluate the impacts of this project should be assembled periodically into a cohesive and integrated document so that well-informed decisions can be made regarding program continuation and so that the information regarq,ing impact documentation will be in the public realm, available for fufure decision making. 5.1 PROGRAMS RELATING TO PROJECT PERFORMANCE AND ENGINEERING Informed sensitivity on the part of the ope rat ions management :to variations in the environment could increase project efficiency and reduce environmental impacts. Perhaps the most s i gni fi cant program would be routine monitoring of total suspended solids and chlorine demand at the intake. This program would enable chlorine and coagulant dosages to be maintained close to optimum levels while reducing the amount of residuals released to the environment. Certain of these studies may be required by permits. Other monitoring programs may be instituted to evaluate the following performance and engineering factors: Frazil ice formation on the intake structure and outfall line. 5-2 Impingement of organisms and ice on the intake screens. Biofouling of the intake structure and outfall line. Sea ice level in relation to the intake structure. Effects of ice stresses (including ice override) on the marine structures and development of an early warning system for ice override events. 5.2 MONITORING FOR PERMIT COMPLIANCE The Section 404, Section 10, NPDES, and PSD permits will require monitoring programs for compliance and for measuring specific effluents and emissions. Other studies would be of interest for an impact documentation and prediction base. These programs will likely include: Continuous or periodic measurement of effluent flow, total suspended sol ids, chlorine residual, settleable sol ids, volatile solids, pH, and temperature. Measurements would be conducted at the mixing zone boundary, and in some cases at the intake, within, and beyond the mixing zone. Measurements of residual biocide and coagulant levels in the outfall, and in sediments determination of backwash cycle frequency, and monitoring for EPA• s 1 ist of 65 priority toxicants. Monitoring the extent of entrapment, impingement and entrain- ment and the fate of fish in the marine 1 ife return system. Validation of predicted emission rates of new sources. Effects of the causeway extension on: ; a. water circulation and salinity (would be used to verify the predictive model used in Appendix D) b. other water quality parameters (e.g., nutrients, temperature) c. sediment accumulation, erosion, grain size and organic content d. fish migrations, numbers, and feeding patterns in relation to the causeway, the intake, and the breach e. invertebrate community structure, abundance, and distribution 5-3 Effects of the discharge on: a. under-ice currents b. sediment size distribution and organic content c. invertebrate community structure, abundance, and distribution d. levels of chlorine reaction products Chemical analysis of the discharge could explore the chemical nature of chlorine reaction products and the interactions between chlorine and the coagulant under arctic conditions. Studies of benthos could be expanded to include evaluation of the reaction to and use of disturbed habitats, such as the gravel fill areas and deposition areas around the discharge, by benthic infauna, epifauna, and fish. Detailed data on entrapment, impingement, and entrainment rates would be used to fully evaluate the performance of the intake system under seasonally changing conditions. Any unusual event, such as equipment failure or high fish density, should be observed and reported in a scientific manner. 5.3 MONITORING OF ACCIDENTS AND SUBSIDENCE Impact assessment and monitoring after a major accident should be designed to suit the nature of the accident. Contingency planning should include detailed monitoring plans for the most likely and potentially most damaging accidents (e.g., a major seawater spill onshore and a marine discharge resulting from low-pressure 1 ine evacu- ation). Preparation of detailed monitoring plans, including designation of responsible parties, would enable adequate description of the relevant baseline conditions (as modified during construction and operation of the facility), an immediate and more efficient monitoring response, and a greater 1 i kel i hood of successful impact assessment. Field subsidence is considered to have a very remote possibility and would be made even more doubtful with waterflooding. However, in light of the low cost of establishing control elevations and periodic surveys, it is considered prudent to establish such a program. This would, however, be in the purview of the State of Alaska Department of Natural Resources and Oil and Gas Conservation Commission. 5-4 (.11 I (.11 TABLE 5.0-1 PRELIMINARY MONITORING PROGRAM SUMMARY Category Parameter Program Monitoring Requiremenda) Duration(b) Fr_e_q_u_~ncy Location(s) Methodology WETLANDS Pad Configuration and Size Bird Mortalities Due to Power L i ne,s FRESHWATER Salmonid Habitat Stream Suspended Solids B,C B,D A,D A,C (a)A -Environmental impact documentation; B -Technical performance evaluation; 1 yr 2 yr 2 yr 1 yr C-Likely to be required for permit compliance; 0 -Suggested for implementation; E -Status undetermined. Once during construction; once following completion Spring, summer, fall Immed i ate l y following and 1 yr following construction Weekly during construction Each new or expanded gravel pad New above-ground power lines from CCP to. base of causeway; four 250-m index sect ions At and downstream of Kuparuk crossing (pipeline to Pad S). Upstream and down- stream of Kuparuk crossing (pipeline to Pad S). Visually inspect and/or measure pad size and configuration for com- pliance with permit descriptions. Walk each section directly under lines (or along windward [western] shore if flooded) noting presence, species, and apparent nature of injury of any dead or injured birds seen. Repeat every other day (3 times) over 6-day period during spring and fall migrations and during peak breeding season. Note weather conditions. Visual inspection of back filled trench and areas downstream. Standard APHA (blEach category would be reviewed every 2 years (or sooner if deemed appropriate) to decide if the category parameter is to be continued, modified, or discontinued. Page 1 of 1b Notes Include 300-m sections in each causeway section if above-ground lines placed along causeway. , TABLE 5.0-1 (continued) Page 2 of 10 I PRELIMINARY MONITORING PROGRAM SUMMARY Requ~-~mend a) Program Moni taring Category Pa_r_a_"!~ter _ Duration{b) Frequency Locat iol}_( s) ME!_~_I!o_d_o 1 ogy Notes --- COASTAL PROCESSES AND SEDIMENTATION Causeway and Coastal Erosion and Effects on Stump Is 1 and A,C 15 yr At 1, 2, 5, 4 stations along Fix permanent bench 15 yr post-extended causeway; marks; plot beach construction 5 siations on Stump profiles (to -1 to -3m (open water) Is 1 and MSL) and sample for grain size analysis. Conduct aerial photogrammetry. Begin with baseline in 1981. Sediment Characteristics A,C 3 yr 3/yr 10 stations around Diver or drop core Baseline in open water existing causeway samples during mid-period prior to start-up. and proposed winter, prior to break- Ul extension. up, prior to freeze-up. I Analyze materials C) collected for grain size, total organic nitrogen, nitrates, total phos- phorus. Sedimentation Rate A,C 5 yr Annual 2 km offshore, Use precision navigation Baseline in summer 1981 (open water) 5 km E and W of system and precision to reconfirm 1979 survey. causeway extension depth finder and/or Repeat in 1983, 1986. in to 0.5-m contour sounding rod to plot bathymetry. OCEANOGRAPHY Hydraulic Model Verification A,C 2 yrs Annual ----Optimally-should be {open water) verified prior to cause- way extension and Meteorology A,C 2 yrs Annua 1 DH 3 Establish station for repeated after extension (open water) continuous recording of is complete. wind speed and direction during open water period. _4 '1 TABLE 5.0-1 (continued) Page 3 of 10 PRELIMINARY MONITORING PROGRAM SUMMARY Require_m_~n_J:_~~-Program Monitoring Category Par~meter Duration(b) Frequency Location( s) Methodology --·---·-Notes Current direction A,C 2 yrs Annual Between Stump Isl~nd Set continuous recording and speed (open water) and mainland; moored current meters for between Stump .Island 6 days; pull and inspect ann causeway; off meters; retrieve data and tip of proposed set for 2 months. Obtain extension; at east vertical current profiles and west boundaries twice daily at each of mode 1 ed area. location during initial 7 days. Water Quality Model Verification Vert ica 1 temperature A,C 2 yrs Annual On 1000-m spacing on Take standard STU pro- and salinity (open water) line along shore files at least twice profi 1 ing inside Stump Island daily during 7-day period east past DH 2; also of concurrent meteoro- on 1 ines from shore logic and current seaward from measurement. <.J1 Storkensen Pt. past I -.....! west end of Stump Is.; through Stump Is. -causeway pass and east of cause- way out to about 5- m contour; also at 5 locations along each side of exist- ing and proposed extended causeway (some 30 stations total). Breach Flow/Impacts Flow rate, temperature A,B,C 1 yr --Place one of STD Take standard measurement salinity stations described in, and on either side of, above on either side breach to determine flow of breach; current velocity, volume, and meter in breach. effects on water quality. TABLE 5.0-1 (continued) Page 4 of 10 j PRELIMINARY MONITORING PROGRAM SUMMARY Requirement (a) Program Monitoring --~~t_e_g_ory Parameter Duration( b) Fr_~quency Lo_cat ion( s) Methodology Notes ---··--.. - Synoptic Water Quality A,E 3 yrs Annual 30 sample stations Use standard technology Include sample concurrent (Total suspended (open water) described in water to collect and analyze with model verification solids, total organic quality model veri-listed parameters. studies. carbon, dissolved fication studies. Sample all stations in organic carbon, Include stations at 1 - 2 days during steady nitrates, phosphates, 300 m and 50 m from NNE wind condition; sulfates, temperature, diffuser in pre-repeat if possible during dissolved oxygen, vail ing current or within 1 day of per- salinity, pH, arnmoni a direction. sistent west wind. [NH3-N]) Discharge Model Verification Dye study A,B,C 1 yr once fP}n 3-dimensional grid Use synoptic look at dye Under open water, use water c ; once within mixing zone dilution within mixing precision navigation under ice zone as tool for veri-system and continuous U1 fying dilution factors monitors; gather appro-I (X) achieved within mixing priate ancillary infor- zone. mation (current, salinity, depth, etc.). INFLUENT WATER QUALITY Flow (m3/day) A,C Permit Cant inuous To be specified Continuous recording duration Total Suspended Solids A,C Permit Weekly Between screens and 24-hr composite Influent samples to be duration strainers taken at approximately the same time of day as effluent samples. Total Suspended Solids B,D Project Daily Between screens and Grab sample or continuous operation strainers. recording Volatile Suspended Solids A,C Permit Weekly Between screens and 24 -hr campos i te duration strainers Temperature A,C Permit Cant inuous To be specified Continuous recording duration Chlorine Demand B,D 1 to 2 yr Weekly Grab sample Use react ion time appro-Use as guide for meeting pri ate for time of chlorine discharge passage through system. requirements. (c)open water dye study is optional. 41 =- Category Parameter ---Requ i remen_t_~~~ EFFLUENT WAT~~__QUALITY Flow (m3/d) A,C Total Suspended Solids A,C Volatile Suspended Solids A,C Settleable Solids A,C Chlorine Residual A,C 01 Ammonia ( NH3-N) A,C I 1.0 pH A,C Temperature (•c) A,C 65 Priority Pollutants A,C Toxicity (96-hr LC5o) A,E TABLE 5.0-1 (continued) PRELIMINARY MONITORING PROGRAM SUMMARY Program Moni taring Duration(b) Frequency _ _L_q_cat i_~~( s) Permit Continuous Downstream of all duration discharge processes Permit Weekly Downstream of all duration discharge processes Permit Weekly Downstream of all duration discharge procesoes Permit Weekly Downstream of all duration discharge processes Permit Cant inuous Downstr'ea1n of all duration discharge processes Permit Monthly Downstream of all duration discharge processes Permit Continuous Downstream of all duration discharge processes Permit Continuous Downstream of all duration discharge processes Permit 1 time Downstream of all duration discharge processes 1 yr Winter and Use water taken summer downstream of all discharges. , . <"''"' , __ , __ , .. ~.~, ...... _)_ ~· , .... . ·.;; ~· .: .. . ..(" . ..---.-.··-~· ·:· ..... , ,._ ...... , ~,._. ,. Page 5 of 10 Methodo log_}: __ Nutes Continuous recording 24-hr composite · 24-hr composite 24-hr composite Continuous recording 24-hr composite Continuous recording Continuous recording Sample during backwash at Use EPA testing proce- a time representative of dures and detection maximum annual discharge limits. (open water) • Conduct standard 96-hr Conduct bioassays during continuous flow bioassays periods of 0.1 mg/1 total using several dilutions residual chlorine. of the main discharge. Use an-site laboratory at ambient water temperature. I TABLE 5.0-1 (continued) PRELIMINARY MONITORING PROGRAM SUMMARY Page 6 of 10 Progr~n Monitoring ---~~t_e_g_o_':_t_l~.!~.r~neter __ Requ i remend a) Duration (b) Fr_e_quency Location(s) Met hodo 1 ogy ·--·-----------~Note:.:s'------ INTAKE SCREENING AND MARINE LIFE RETURN (J1 I 1-' 0 Fish Density and Mo~ality Rate in Return System Entrapment Impingement Entrainment A,B,C A,B,C A,B,C A,B,C Permit life Permit duration Permit duration Permit duration Concurrent with impingement and entrainment studies, weekly in first year; ·evaluate need thereafter. Weekly for 1st year; bi-weekly for 2nd year; monthly in 3rd . year. Same as above Marine life.return outfall; in-plant sampling division. Inside treatment plant, upstre~ of screens. At intake screens In-plant: divert marine life return water through holding tanks. Note living and dead organ- ; sms; at 1 east semi- annually, hold for 96- hour latent mortality. Acoustic monitor and tape for 1 min of every 5 for 24-hr period. During periods of good visi- bility, also monitor continuous recording video on same monitoring frequency. TV monitor on schedule described above (for en- trapment) during periods of good visibility; if travelling screens are installed, count impinged fish and invertebrates each time they are rota tell. In main outfall line Filter a portion of the intake water downstre~ of screens on 6-hr inter- vals (4 per day) using standard mesh (e.g., 0.5 mm) plankton nets; evalu- ate nature and quantity of entrained biological material (primarily ichthyopl ankton and macroinvertebrates). Note fish, invertebrate species, size, condition, quantity. Observations during periods o~ unusual conditions (initial start-up, icing, etc.) would be necessary. Observations during periods of unusual condi- tions (initial start-up, icing, etc.) would be necessary. Observations during periods of unusual condi- tions (initial start-up, icing, etc.) would be necessary. Observations during periods of unusual condi- tions (initial start-up, icing, etc.) would be necessary. Miti'ftt.ffl:~-..i.~'r~"\' (:'"r.i.·;__~~ ·, .• : ·;, •·,:,, · ,\~, ,;;~.!'!-.;'·'· :~··-,:; ~-, •. ;.:,.. . '#flj ,, TABLE 5.0-1 (continued) Page 7 of 10 PRELIMINARY MONITORING PROGRAM SUMMARY Requi rern_e_nd a) Program Monitoring ___ Category Parameter Duration(b) Freguenc~ _____ Lo_c:_at ion ( ~L .. ___ Met ho<!_o_l ogy Notes RECEIVING WATER ... ·:~~ ... :7:'"··--~:;..:,::..:.~:.:,.::· . BIOTA AND SEDIMENTS In fauna A,C Perrni t Annual 20 randomly selected Grab or diver sampling; Permanently locate duration stations within 460 0.04 m2 minimum area by samples and repeat in rn east and west of 15 ern deep; sieve to 1.0-subsequent years. Obtain the diffuser center-rnm mesh size. At each baseline in open-water 1 ine and 460 m north station, take second season preceding start- and south of the sample and measure per-up. diffuser ends. cent organic composition. Individual Species Liocyma fluctuosa A,C Permit Semi -annua 1 for Eight of infauna Grab or diver sampling; Ainpharete vega duration first two yrs. monitoring stations increase replication Then may be p 1 us two westward until get adequate num- U1 modified by along 4.3-m contour. bers to analyze Liocyma I DEC. condition index and soft ...... tissue residual chlorine ...... and chlorinated hydro- carbon 1 eve 1 s. Also analyze Ampharete soft tissue for res1dual chlorine and chlorinated hydrocarbon levels. Sediments . A,C Permit Annual Same in individual Take additional grab sam-Obtain baseline prior to duration species' studies ple and analyze for total discharge; first sample (10 stations) residual chlorine, chlor-within 6 months of first inated hydrocarbons, and discharge. ammonia. Chlorinated Hydrocarbon Uptake A,D 20 yrs Annual Fish/invertebrates Measure flesh and liver Establish baseline prior from west side of chlorinated hydrocarbons to start-up. mixing zone plus in arctic cod fmn mixing control; marine zone and in marine rnam- mammals from mals (including bowhead Kaktovic harvest whale) from subsistence harvest as near Prudhoe Bay as possible. U1 I 1-' N' ilii;;rt·;·· I TABLE 5.0-1 (continued) PRELIMINARY MONITORING PROGRAM SUMMARY Page 8 of 10 Program Monitoring Category Parame!~r-·. Requiremenda) Duration(b) Frequency Location(s) ·Methodology Notes IMPACTS ON BENTHIC DISTRIBUTIONS In fauna Epifauna . FISH MOVEMENT STUDIES A,E A,E A,C 3 yrs; 1981, 1983, 1986 3 yrs; 1981, 1983, 1986 5 yrs 1981- 1985 --------~ Annual (open water) Annual (semi-ann1,1al in 1986) Continuous during open water for mi- gration; 4-yr for attraction to intake and discharges. Woodward-Clyde stations 1, 2, 5, 7, 9, 12, 13, 15, 25, 30, 37, 43, 44, 45, 50, a station on each side of exten- sion, two stations in the discharge vicinity Woodward-Clyde stations 1, 2, 5', .7. 9, 12, 13, 15, 25, 30, 37. 43, 44, 45, 48, 50, a stat ion on each side of causeway extension, two stations in the discharge vicinity Both sides of cause- way and along natural shoreline: also discharge and marine life outfall vicinity. Diver or grab sampler 0.01 to 0.02-m2 cores 5 replicates per stat on sieve to 1.0 mm. Replicate drag-net or epibenthic pump sampler. Tag and release fish with external anchor and internal sonic tags. Establish beach seining, fyke netting and acoustic and sonic tag monitoring program to document move- ment around causeway and through breach. Fyke nets should be direc- tional. Document tag recoveries in Colville and Kaktovik fisheries. Measure surface and bottom water temperature and salinity concur- rently. Emphasize distribution and abundance of Mysis, Onisimus, Gammarus. Look for attract1on to dis- charge. Look for: concentrations around causeway, intake, and outfall; migration delays, unusual predation patterns. ····- TABLE 5.0-1 {continued) PRELIMINARY MONITORING PROGRAM SUMMARY . Program Monitoring CategoryParamet~r _____ ReqiJJrE!menda) Duration{b) Frequency Location{s) Methodology FACTORS INFLUENCING FISH DISTRIBUTION In Situ and HOdeTTng Studies A,D 5 yrs Annual Coasta1 Beaufort Use standard biological {open water) Sea from Colville and chemical sampling to Canning Rivers measurement techniques supplemented with state- of-the-art acoustic methods to develop and verify model of behavior of key species in response. to . .ll.i!rJi!t.ions in temperatiii"e arrcr······' .......... salinity. Laboratory Tests A,D 2 yrs --Laboratory Determine behavior of tn facilities important fish species in I ....... preferably on relation to temperature w Beaufort Sea and salinity in labora- tory gradient tanks. FACTORS INFLUENCING INVERTEBRATE DISTRIBUTION A,C 2 yrs Annual From causeway west-Use unbaited directional {open water) ward into Simpson traps to attempt to Lagoon determine "flux" of invertebrates in and out of the pass between the causeway and Stump Island under various meteorological condi- tions and at various times of the year; especially immediately following break-up . . ARCTIC ENGINEERING Ice Growth in Offshore Structures B,D 2 - 3 yrs Semi-annual Several locations Core through gravel to spring/fall in caus'eway and document rate and extent proposed extension of freezeback and thawing in the struc- ture. Cores shou 1 d penetrate to subsea permafrost to document any impacts. , Page 9 of 10 Notes U'l I 1-' j Category Parameter Ice Growth at Intake and Discharge Ice Rideup and/or Override, ~ Frazil Ice in Intake System Biofouling in Intake System TABLE 5.0-1 (continued) PRELIMINARY MONITORING PROGRAM SUMMARY Program Monitoring Reg_uJr~mend a) Duration( b) Frequency Location( s) B,D A,B,D B,C B,C 2 yrs Project life Project 1 ife Project life Monthly during .1st year Daily during freeze-up and break-up Daily during 1st winter; less frequent thereafter Whole system inspection annually; screen inspec- tion as appro- priate. Intake and discharge vicinity Along existing and extended causeway (including treat- ment plant berm) In forebays, on screens, and in bypass system In forebays, on screens, and in bypass and return system Methodology Observe ice growth, thickness and character in intake and discharge. vicinities. Evaluate measures to reduce growth at intake (e.g., snow fencing, cover with black plastic). Observe and note ice stress and extent of any ice rideup on causeway. Applicant notify COE/ CRREL if rideup exceeds about 8 m laterally (1.6 m vertical). Observe ice presence in water column and build-up on structures using UTV, view ports, and surface observations. Observe biofouling build- up on surfaces using UTV, surface and diver obser- vations. Page 10 of 10 Notes Effective measures to reduce ice growth could reduce design water depth requirement for future intakes. ~~;:¥-ii:\0.~r:~·.:;,~,.,o'<"J:·:Ii:··J;·,{·,~·lhf;~:.~C<::>l',,,.,<t '>'·:l:;,c;,._ f:>":<>.;1;,;_o1 •·'·'j(.'·"'·"·e·;"'"""'''~~"'"'"''·;:;-,,,.<''"'"'-"''• ,-;. ,.,. • ,, .. ,,,:-;...,::·•·r"""""k\!ii.'i&?d-l>iWj'fl::~o\~l,~)..;,'t,<;-~.)l.._,,,, .. ..:x,w.;7':····· '"'~ ,., .• ·.:<· ,~ •• ~., •• o•< ,;.,.;\,'•'-• •.•. ::..'"'""'""·"'-" .: • ·· '., .. ,,:·. ,. · ·· · < , ••. ,,,,;, ·zm 5.4 POSSIBLE PERMIT CONSTRAINTS In the course of continued evaluation of the project and review of the DEIS, various suggestions have been generated which might reduce or e 1 imi nate certain env i ronmenta 1 effects of the proposed project. These suggestions are presented below. It is important to note that these are presented as preliminary concepts and apply only to certain alternatives. These and possibly others will be considered during final permit processing and applied appropriately to the action taken. The pass between Stump Island and the causeway would be maintained in such a manner as to avoid effects on fish and wildlife· populations due to restric¢ed passage of organisms. u Adequate drainage would be provided 1[\through or past all work pads. L u. Access and activity on the west' low-p'ressure pipeline and road route would be restricted to avoid disturbance to wildlife. Adequate provision would be made for the passage of caribou (1.5-m, 5-ft, clearan~e for above ground pipelines). Dredged pipeline trenches woulq be backfilled. Five years prior to project abandonment, a detailed abandon- ment p 1 an wou 1 d be . prepared and presented to agencies for review and approv9.l. It would contain measures to remove the permitted facility and restore the landscape and marine environment to ~atural conditions in a rapid and practical manner. Temporary fish guidance measures waul d be investigated for use during times of high fish concentrations to encourage passage through the causeway breach or avoidance of the seawater intake. In the event treated seawater waul d be discharged from the low-pressure pi pel ine·s, it waul d be discharged on the surface of the ice (in winter). Upon completion of detailed design and: prior to construction, the applicant w,ould provide agencies with drawings and narratives that present specifics of project construction and operation related to environmental effects. One year prior to project start-up, a saltwater spill contingency plan would be submitted for review and approval. 5-15 -- A program would be implemented to document environmental effects and technical performance of the project. This would include provisions for program management, reporting, and review in the public realm . Copies of operating logs and summaries of facility operations would be sent semi-annually to the Corps of Engineers. The Corps of Engineers would be routinely notified prior to the initiation of studies at the site and upon completion of studies, and would be routinely sent copies of final reports of such studies unless they are of a proprietary nature, being a trade secret or of a patentable nature. The Corps would be notified within 48 hours of the occurrence of 11 extraordinary 11 events such as major system failures, screen failures, ice-induced intake shutdown, structural failure, or massive fish ingestion. 5-16 CHAPTER 6.0 LIST OF PREPARERS AND REVIEWERS LIST OF PREPARERS The following people were primarily responsible for preparing this Environmental Impact Statement. CORPS OF ENGINEERS: William D. Lloyd Benjamin B. Kutscheid Richard J. Gutleber David L. Ferrell DAMES & MOORE: James E. Hemming Jonathan P. Houghton Paul w. Neff Pamela M. Knode Nancy Young PRINCIPAL iNVESTIGATORS: James Anderson* (Helton Engineering and Geological Consultants*) Glenn R. Cass James D. Cool Rhea M. Crossfield David E. Erikson Kaye R. Everett* Charles B. Fahl Expertise Civil Engineering, Administration Project Manager, Wetland Ecology, En vi ronmenta l Assessment Permit Processing Permit Pro~essing Managing Principal- in-Charge, Terrestrial'Mammals, Appendix L Project Manager, Marine Biology Project Coordinator Project Editor Project Illustrator Experience 19 years, civil engineer with Corps of Engineers; 2 years, Chief, Envi- ronmental Section; 13 years, civil engineer, Los Angeles Water & Power Department 9 years, biologist/ecologist for Corps of Engineers; 1 year, planning associate with Board of Engineers for Rivers and Harbors; 2 years on Illinois Natural History Survey 9 years, biologist for Corps of Engineers 3 years, biologist for Corps of Engineers; 2 years, biologist for National Marine Fisheries Service 17 years, biological studies; 1 year, Manager, Alaska Operations 7 years, project manager and principal investigator, marine and aquatic biological studies 6 years, project manager and coordinator 6 years, public relations and research 12 years, graphics and illustration Reservoir Engineering 26 years, petroleum engineering Appendix K Acoustics, Appendix G Land Use Vegetation, Wetlands, Appendix L Birds, Marine Biology, Vegetation Appendix L Air Quality Meterology 9 years, project engineer 6 years, planning and economics 5 years, arctic terrestrial and aquatic ecosystems 8 years, ornithologist, field biologist PH. D. soil scientist, Ohio State University 8 years, air quality, meteorology, climatology * Consultants to Dames & Moore 6-1 Professional Discipline Civil Engineer Ecologist Biologist Fisheries Biologist Biologist Fisheries Biologist Management Journalism Technical I1lustrat ion Reservoir Engineer Engineering Acoustics City Planning Biologist/Botanist Biologist/Botanist Soil Scientist Air Quality . ~ Paul S. Ford Nick Fotheringham Peter T. Hanley Gordon S. Harrison* John s. Isakson Douglas F. Jones Thomas G. Krzewinski Dennis C. Lees Wayne S. Lifton John E. Lobdell* Rod s. March Michael Miller John W. Morse 11 John F. Nixon (Hardy Associates (1978) Ltd.)* Laurence A. Peterson* Richard H. Ragle* Akshai K. Runchal William w. Wade Donald A. Walker* Patrick J. Webber* WORD PROCEsSING: LIST OF PREPARERS (Continued) Expertise Appendix B, Project Description Marine Biology Petroleum Geology, and Economics Socioeconomics Marine Bi o 1 ogy, Appendix E Physical Oceano- graphy, Appendix C Geology Marine Biology Experience 18 years energy resource and site engineering 2 years, senior ecologist; 9 years, assistant professor, University of Houston 6 years, project manager & principal investigator; petroleum development scenarios 8 years, social and economic research 2 years, project biologist; 11 years, fisheries biologist, environmental scientist 2 years, project coastal engineer; 7 years research and development scientist 9 years, arctic engineering 15 years, marine biology and inverte- brate zoology Marine Intake Impacts, 2 years, aquatic baseline, design and Appendix H impact studies; 4 years, resear.ch associate Anthropology Geology, Physical Oceanography Coastal Processes, Appendix I Terrestrial Biology, Wetlands, Appendix L Ice Forces, Appendix J Fresh and Marine Water Quality, Appendix C, Appendix F Ice Mechanics Hydrodynamic and Water Quality Modeling, Appendix D Petroleum Economics, Appendix M Appendix L Appendix L 8 years, instructor of anthropology, University of Alaska 5 years, technical assistant 3 years, ocean engineering 6 years, environmental assessments 10 years, arctic engineering 9 years, water quality investigations 19 years, arctic geology 12 years, coastal and offshore engineering 16 years, socioeconomist and financial analyst Plant ecologist, University of Colorado Institute of Arctic and Alpine Research Ph.D, plant ecologist, University of Colorado, Institute of Arctic and Alpine Research Cleone White, Sherry Tucker, Margaret Bollman * Consultants to Dames & Moore 6-2 Professional Discipline Civil and Environmental Engineering Marine Ecologist Geologist Socioeconomist Fisheries Biologist Coastal Engineer Ci vi 1 Engineer Marine Biologist Aquatic Ecologist Anthropologist Geologist Coasta 1 Engineer Biologist Arctic Engineer Environmental Scientist Arctic Geologist Mathematical Modeler Economist Plant Ecologist Plant Eco 1 og i st LIST OF COOPERATING AGENCY REVIEWERS National Marine Fisheries Service: Frank L. Wendling, Fishery Biologist, Anchorage U.S. Environmental Protection Agency: ·William B. Lawrence (Review Coordinator), Dredge and Fill Permit Coordinator, Anchorage Wally Scarburgh (Draft NPDES Permit), Environmental Scientist, Anchorage U.S. Fish and Wildlife Service: Rosa Meehan, Fish and Wildlife Biologist, Fairbanks Thomas C. Rothe, Wildlife Biologist, Anchorage CORPS OF ENGINEERS' REVIEWER Arctic Environmental Information and Data Center: David Hickcock Robert Means Charles Evans David Spencer Rosita Worl Joseph La Belle Jim Wise Willi am Wi 1 son Al Comiskey 6-3 May 15, 1980 Colonel Lee R. Nunn District Engineer Alaska District, Corps of Engineers P.O. Box 7002 Anchorage, Alaska 99510 Dear Colonel Nunn: U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Marine Fisheries Service 701 C St. Box 43 Anchorage, Alaska 99513 We have received your letter requesting our participation as a cooperating agency in the preparation of an environmental impact statement {EIS) for the Prudhoe Bay Unit Waterflood Project. Speaking for the Alaska Region be advised that we•11 be pleased to serve as a cooperating agency in an advisory status during preparation of the EIS. Sincerely, ' . .. ---) ~ ...... -... ,_, -- . .._ • '-<' :::-'--..~ .•• ...._~ ~--Ronald J. Morris Supervisor, Anchorage Field Office 6-4 U. S. E N V I R 0 N M E N T A L P R 0 T E C T I 0 N A G E N C Y REPLY TO ATIN OF: Colonel Lee R. Nunn District Engineer ALASKA OPERATIONS OFFICE Room E535, Federal Building 701 C Street Anchorage, Alaska 99501 11 DEC 1Si~i Alaska District, Corps of Engineers P. 0. Box 7002 Anchorage, Alaska 99510 Dear Colonel Nunn: In response to your recent request, EPA would be pleased to be a cooperating agency during your preparation of the Environmental Impact Statement (EIS) for the proposed Prudhoe Bay Waterflood Project. The Coun:il on Environmental Quality regulations list some of the duties of a cooperation agency (40 CFR 1501.6(b).) We intend to continue our full participation in the seeping process and in the NEPA process as .a whole. However, while we have great interest in this EIS, our limited resources and other priority program commitments will ·preclude our full involvement in all aspects of EIS preparation. While you have not yet described the level of involvement you would like from us, it may simplify the process to let you know what we believe would be the most effective use of our resources and expertise. The Corps wants to base its EIS on environmental information which will be provided by the applicants. The Corps will be responsible for the accuracy of this information in accordance with 40 CFR 1506.5(a). We believe that our limited personnel and financial resources would be most useful functioning as part of the Corps• independent evaluation of the material provided by the applicants. In addition, we would be glad to review critical portions of the DEIS before publication. Identification of the sections that would benefit most by this review can be completed later in the process. We look forward to developing a firm working relationship between our offices and to producing a high quality EIS with you. 6-5 Your Environmental Resources staff should continue to work with Bill Lawrence, of my staff, who will coordinate EPA's participation in the NEPA process. · Sincerely, ~ /~/7>'3~ W; James Sweeney {_____,) Director cc: Environmental Evaluation Branch 6-6 UNITED STATES DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE 1011 E. TUDOR RD. REPLY REFER TO: ANCHORAGE, ALASKA 99503 (907) 276-3800 15 NOV mag Colonel Lee R. Nunn District Engineer Alaska District, Corps of Engineers P.O. Box 7002 Anchorage, Alaska 99510 Re: NPACO No. 071:-;.0YD:.:.2.~.790291. Beaufort Sea 20 NPACO No. 071-0YD-2-790292 Beaufort Sea 21 NAPCO No~ 071-0YD-2-790293 Beaufort Sea 23 Dear Colonel Nunn: The interested bureaus of the Department of the Interior have reviewed the referenced public notices ·of application by ARCO Oil and Gas Company and SOHIO Petroleum Company to construct the Waterflood Project at Prudhoe Bay. This is a massive project requiring outfall and intake structures offshore in Prudhoe Bay, expansion of the West Dock and numerous roads, access pads, drill pad extensions and other pads comprised of fills in Prudhoe Bay and wetlands of the North Slope near Prudhoe Bay. Your office is requ1r1ng the preparation of a third party environmental impact statement (EIS) prior to approval of permits required for this project. I believe that it is essential that the EIS adequately address the following points: a. The relationship of this project to existing and projected North Slope development. b. The impact of offshore facilities on the nearshore marine environment. -c. The impact of onshore facilities to wetlands of the North Slope and the fish and wildlife species inhabiting those wetlands. 6-7 - Colonel Lee R. Nunn Anchorage, Alaska Page 2 d. The competition of gravel requirements of this project with other gravel needs and resultant impacts on fish and wildlife. I have attached a list of Fish and Wildlife Service concerns relative to this project which we will be 'prepared to discuss in greater detail at the EIS scoping meeting scheduled for November 15, 1979 in Anchorage. The scoping process should serve as an effective means to focus on significant issues associated with the waterflood project. I believe that this, and future public meetings associated with the EIS, will be most effective if held in Fairbanks and Barrow as well as Anchorage. The Fish and Wildlife Service is looking forward to working closely with the Corps in development of an EIS which will clearly and concisely lay out all practicable alternatives relative to prevention and mitigation of fish and wildlife impacts associated with this project. Sincerely yours, Attachment cc: Area Director, HCRS, Anchorage Area Director, NPS, Anchorage Bill Laurence, EPA,_Anchorage Frank Wendling, NMFS, Anchorage Lester Suvlu, NSB, Barrow Herman Schmidt, SOHIO, Anchorage Joe Solove, ARCO, Anchorage Scott Grundy, ADF&G, Fairbanks Rick Smith, ADSL, Fairbanks Paul Bateman, ADEC, Fairbanks Field Supervisor, NAES, Fairbanks 6-8 1-z Ill :& Ill > ..I 0 Photo Courtesy Sohio Alaska Petroleum Company CHAPTER 7.0 PUBLIC INVOLVEMENT During the course of environmental assessment and preparation of the environmental impact statement (EIS) for the proposed action, an active program for public involvement has been pursued. This Chapter describes those activities, including the role of the cooperating agencies and a listing of recipients of the EIS. Appendix A includes the results of the scoping process. In September 1979, a public notice was issued by the Alaska District indicating receipt of three joint permit applications from Sohio Alaska Petroleum Company and ARCO Oil and Gas Company. The notice also gave a brief description of the applicant 1 s proposal, indicated an EIS would be prepared, and invited comments. A notice of intent to prepare an EIS was subsequently published in the Federal Register that briefly described the proposed action and also invited comments. In September 1979, various agencies and environmental organizations were asked to comment on prospective consulting firms, one of which was to be selected to prepare an environmental assessment that would form an important part of the Corps 1 EI S. Based . upon these comments and other factors the applicants chose the firm of Dames & Moore. An interagency meeting was held in Anchorage on November 15, 1979, where the applicant presented the proposed project, the staff of Dames & Moore were introduced, and the EIS preparation process des- cribed. In November and December 1979, public meetin.gs were held in Anchorage, Fairbanks, Kaktovik, Nuiqsut, and Barrow, Alaska. Due to the lack of public attendance at the meeting in Anchorage, no presentations or commentary were heard. The meetings were preceded by a mailed brochure and media coverage. On February 13, 1980, the results of this scoping process were mailed to interested parties and comments invited. As various sections of the pre-draft environmental analysis became available they were coordinated with the applicant, the cooperating agencies, and various other agencies. On April 4, 1980, the Draft Environmental Analysis was coordinated with the applicant and many local, State, and Federal agencies. Comments were considered and incorporated into the DEIS where appropriate. On 6 June 1980 a notice was published in the Federal Register indicating the availability of the DEIS and the 21 July 1980 closing date. Upon request from the U.S. Dept. of Interior the closing date was extended to 31 July 1980. A public hearing was held jointly by the Corps of Engineers and the Environmental Protection Agency in Barrow, Alaska 15 July 1980 to provide further opportunity for comment. A public notice and revisions were issued in August and September 1980 that described changes to the proposed project made by the applicants, primarily in response to publjc concerns. 7-1 The FEIS was published in October 1980 and included a separate summary with Inupiaq translation . This was distributed widely on the North Slope to increase communication and public involvement . DRAFT ENVIRONMENTAL IMPACT STATEMENT MAILING LIST *U .S. Environmental Protection Agency *U.S. Fish and Wildlife Service *Alaska Outer Continental Shelf Office, Bureau of Land Management *Cold Regions Research and Engineering Laboratory *Outer Continental Shelf Arctic ~roject Office *U.S . Geological Survey *Interagency Archaeological Services, U.S. Dept . of Interior *U.S. Army Engineer Waterways Experiment Station *U.S. General Accounting Office *Federal Aviation Administration *U .S. Department of Energy i *Federal Energy Regulatory Commission *U .S. Department of Housing and Urban Development *Coastal Engineering Research Center *Alaska Resources Library *Advisory Council on Historic Preservation *Division Engineer, North Atlantic Division, Corps of Engineers *Office of the Chief of Engineers *Board of Engineers for Rivers and Harbors *Bureau of Indian Affairs *Bureau of Land Management *Bureau of Mines *U .S. Coast Guard *Federal Power Commission *National Marine Fisheries Service *National Park Service *Heritage Conservation and Recreation Service *National Weather Service *National Ocean Survey *National Oceanic and Atmospheric Administration *National Science Foundat i on *U.S. Dept. of Health, Education and Welfare *U.S. Soil Conservation Service *U .S. Department of Commerce *Honorable Ted Stevens *Honorable Mike Gravel *Honorable Don Young *Assistant to Secretary, U.S. Department of Interior *Federal Pipeline Inspector *State of Alaska, A-95 Clearinghouse *Honorable Terry Gardiner *Received a copy of the DEIS. - 7-2 *Honorable Clem Tillion *Alaska Power Administration *Honorable Jay S. Hammond *Elmer E. Rasmuson Library, University of Alaska *North Slope Borough *Fairbanks -North Star Borough *Fairbanks Public Library *Anchorage Public Library *Barrow Public Library *Mayor, Fairbanks, Alaska *Mayor, Kaktovik, Alaska *Mayor, Nuiqsut, Alaska *Mayor, Anchorage, Alaska *Mayor, Barrow, Alaska *Alaska Center for the Environment *Fairbanks Environmental Center *Trustees for Alaska *Sierra Club *Alaska Press Club *Environmental Information Center, Inc. *Fairbanks Industrial Development Center *Alaska Native Foundation *Arctic Slope Regional Corporation *League of Women Voters *Alaska Conservation Society *National Wildlife Federation *Arctic Environmental Information and Data Center *Cooperative Wildlife Research, University of Alaska *Institute of Marine Sciences, University of Alaska *Institute of Water Resources, University of Alaska *Audubon Society *Friends of the Earth *Alaska Federation of Natives *Alaska Oil and Gas Association *Jones & Stokes Associates *Peter Barns, USGS *J . Gosink, University of Alaska *R & M Consultants *Robert R. Everitt, ESSA *Bill Sackinger, Geophysical Institute, University of Alaska *Brian Mathews, Geophysical Institute, University of Alaska *Joan Gosink, Geophysical Institute, University of Alaska *Sathy Naidu, Institute of Marine Sciences, University of Alaska *Peter Craig, LGL *Don Schell, Institute of Water Resources *Max Dunbar, McGill University *Erk Reimnitz, USGS *LGL Consultants *Sealaska Corporation *Woodward-Clyde Consultants *Rece1ved a copy of the DEIS . 7-3 *Institute for Alpine and Arctic Research, University of Colorado, Boulder *Institute of Social and Economic Research, University of Alaska *Oceanographic Institute of Washington *Resource Development Council, Anchorage *American Petroleum Institute *Western Oil and Gas Association *D.L. Chamerlan, Atlantic Richfield Corporation *ARCO Oil and Gas Company *Sohio Alaska Petroleum Co . *Exxon Corporation *Alyeska Pipeline Service Co. D. D. Barlow *Seirra Club, Juneau *Nelson Avakahna *Walt Audi *Paul Scott *Harding-Lawson Assoc. *Preston-Thorgrinson *Milton H. Steinmueller School of Public Affairs, Indiana University *Anchorage Daily News *Fairbanks Daily News Miner *Alaska Construction and Oil *Alaska Industry Magazine *Alaska Business News Miner *Arctic Slope Technical Service *Culp-Wesner-Culp *Alaska Legal Service Corp. *Terris and Assoc. *TAMS *K. R. Everette Paul Friesema *B. J. Whitley, Jr. *Jay A. Greenwalt Rockwell International Alaska Airlines National Marine Fisheries Service -Portland Greenpeace DOWL Engineers Petroleum Information Corp. Susan Pozzi Oystein Hawn Inupiat Community of the North Slope Raymond Neakak Gordon Robiliard DMJM *U .S. Dept. of Agriculture U.S . Army Engineer School *Rece1ved a copy of the DEIS . - 7-4 CHAPTER 8.0 REFERENCES Aagaard, K., 1976. STD mapping of the Beaufort Sea shelf. In: Environmental assessment of the Alaskan continental shelf, Vol. 11, physical oceanography and-meteorology. Principal investigators• reports for the year ending March 1976. NOAA/BLM. (editor), 1978. Physical oceanography and meteorology. In: Interim synthesis report: Beaufort/Chukchi Outer Continental Shelf Environmental Assessment Program, NOAA. ---:--' and D. Hangen, 1977. Current measurements in possible disposal regions of the Beaufort Sea. Annual P.I. reports, environmental assess- ment of the Alaskan continental shelf Vol XIV, transport. NOAA/BLM. A9EC, 1979. Water quality standards. Alaska Dept. of Environmental Conservation, Feb. 1979, 34 pp. AEIDC, 1976. Alaska regional profiles: arctic region. Univ. of Alaska, Anchorage, Alaska. -:--:;---' 1980. Environmental review of summer construction of gravel islands: Sag Delta No. 7 and No. 8, Stefansson Sound, Alaska. Prepared for Sohio Petroleum Company, Anchorage, Alaska. Ahvakana, L., 1979. Moore. Personal communication to J. Houghton, Dames & Alaska Department of Community and Regional Affairs, 1980. Alaska taxable 1979. Juneau, Alaska. Alaska Department of Fish and Game, 1980. Comments on waterflqod FEIS. Alaska Department of Labor, 1978. Statistical quarterly: third quarter. Juneau, Alaska. Alaska Department of Law, 1980. Letter from G.T. Koester to B.W. Hostrop (BLM), March 3. Alaska Department of Natural Resources, 1979a. Estimated onshore gravel use. , 1979b. Finding and decision of the commissioner pursuant to AS ~8~3.~o=5.035(a) (14) concerning the proposed Beaufort Sea oil and gas lease sale. October 25, 1979. Alaska Department of Revenue, 1976. Summary of Alaska Department of Fish and Game hunting and fishing license Sales. Juneau, Alaska. 8-1 , 1979. Revenue sources FY 1979-81. Juneau, Alaska. -- Alaska Economic Report, 1980. Dome study: giant platforms in Canada Beaufort Sea. August 1, 1980. 24 ice-breaking tankers, 12 Alaska Information Service, Albrecht, C. (Alaska Dept. Natural Resources), 1980. communication to P. Knode, Dames & Moore. Personal Alexander, V., C. Coulon, and J. Chang, 1974. Studies of primary productivity and phytoplankton organisms in the Colville River system. In: Environmental studies of an arctic estuarine system, final report. Institute of Marine Science, Report R74-1, University of Alaska, Fairbanks, Alaska, pp. 283-410. , C. Coulon, J. Chang, and M.C. Miller, 1977. -=-p-:r-;p:-::-e....-1 ine haul road on nearby ponds and 1 akes across Slope. Annual progress report to U.S. Energy Research Administration. University of Cincinnati, Ohio. Effects of the A 1 ask a • s North and Development American Public Health Association, 1975. Standard methods for the examination of water and wastewater. Washington, D.C., 1193 pp. Andersen, S., 1970. ~uditory sensitivity of the harbor porpoise, Phocoena phocoena, pp. 255-288. Anderson, D.O., 1979. Archaeology and the evidence for the prehistoric development of Eskimo culture: an assesment. Arctic Anthropology, 16(1): 16-26. ANF, 1979. Report on local hire. Prepared for North Slope Borough, 25 p. AOGCC (Alaska Oil and Gas Conservation Commission), 1980. Comments on interim drafts, waterflood environmental assessment. AOGD, 1980. Application revision, ARCO Oil & Gas Co., a division of Atlantic. Richfield Co., for National Pollutant Discharge Elimination System Permit to cover waterflood project seawater treating plant at Prudhoe Bay, Alaska. March 7, 1980. Arctic Institute of North America, 1974. The Alaskan arctic coast. Report prepared for U.S. Army Corps of Engineers, A 1 ask a District. Arthur, J.W., and J.G. Eaton, 1971. Chloramine toxicity to the amphipod Gammarus pseudolimnaeus and the flathead minnow (Pimephalus promelas). J. Fish. Res. Bd. Canada, 28:1841-1845. Bailey, A.M., 1948. Birds of arctic Alaska. Colorado Museum of National History, Popular Series, No. 8. 317 pp. 8-2 Balding, G.O., 1976. Water availability, quality, and use in Alaska. U.S. Geological Survey, Open-file Report 76-513, 236 pp. Barnes, P. (USGS), 1979. Personal communication (December 3) to D. Jones, Dames & Moore. --.--'E. Reimnitz, G. Smith, and D. McDowell, 1977. Bathymetric and shore 1 i ne changes in northwestern Prudhoe Bay, A 1 ask a. Northern Engineer 9(2). , R. Ross, 1980. Fall storm, 1979 -a major, modifying coastal -ev_e_n...-t. In: P. Barnes and E. Reimnitz (Ed.), Geologic processes and hazards of the Beaufort Sea shelf and coastal regions. Quarterly P.I. reports, environmental assessment of the A 1 ask an continental shelf. NOAA/BLM, Boulder, Co. Barry, R.G., 1977. Study of climatic effects on fast ice extent and its seasona 1 decay along. the Beaufort -Chukchi coasts. In: Environmental assessment of the ·Alaskan continental shelf, Vol. 14, transport. Environmental Reseach Laboratories, NOAA, Boulder, Co., pp. 574-743. , R.E. Moritz and J.C. Rogers, 1979. =Be_a_u...,..fort and Chuckch i sea coasts, A 1 ask a. Technology, Vol. I, pp. 129-152. The fast ice regions of the Cold Regions Science and Battelle Northwest Laboratory, 1979. Alaskan environmental research. In: Annual report for 1978 to the DOE Assistant Secretary for Environ- ment. Part 2 supplement -ecological sciences, pp. 12,0-12.24. Bateman, P., (Alaska Department of 'Environmental Conservation), 1979. Personal communication (December 18) with L. Peterson, L.A. Peterson & Associates. Bee, J.W. and E.R. Hall, 1956. Mammals of northern Alaska. University of Kansas, Museum of National History, Miscellaneous Publication No. 8. 309 p. Beehler, C., M. B\.lshdosh, K. Tarbox, and G. Robilliard, 1979. Occur- rence of kelp offshore of Prudhoe Bay, A 1 ask a. In: Environmental studies of the Beaufort Sea -Winter 1979. Report prepared for Prudhoe Bay Unit by Woodward-Clyde Consultants, Anchorage, Alaska. Bellanca, M.A., and D.S. Bailey, 1977. Effects of chlorinated effluents on an aquatic ecosystem in the lower James River. J. Water Pollut. Control Fed., 49(4):639-645. Bendock, T.N., 1977. Beaufort Sea estuarine fishery study. report to NOAA/BLM prepared by.Alaska Dept. Fish and Game. 61 p. 8-3 Final , 1979. Beaufort Sea estuarine fish study. In: Environmental ~a~ss~e~ssment of the Alaskan continental shelf. Final reports of principal investigators-Vol. 4, biological studies. NOAA, Boulder, Colo. pp. 670-729. Berg, L., J. Brown and R. Hagen, 1978. Thaw penetration and permafrost conditions associted with the Livengood to Prudhoe Bay Road, Alaska. Proceedings of the Third International Permafrost Conference, Edmonton. Bergman, R.D., 1974. Wetlands and waterbirds at Point Storkersen, Alaska. Ph.D. dissertation. Iowa State University. 58 pp. , R.L. Howard, K.F. Abraham, and M.W. Weller, 1977. Water birds -a-nd~their wetland resources in relation to oil development at Storkersen Point, Alaska. U.S. Department of the Interior, Fish and Wildlife Service, Resource Publication 129, Washington, D.C. 38 pp. Bilello, M.A., 1979. Decay patterns of landfast sea ice in Canada and Alaska. In: R.S. Pritchard (Ed.), Sea ice procesess and models. University of Washington Press, Seattle. Bird sa 11, D .A., and D. W. Norton, 1980. Beaufort Sea environmental assessment and technical evaluation studies: measurements of the effects of the Prudhoe Bay Unit waterflood· project (Draft). University of Alaska, Fairbanks. Black, R.F., 1964. Gubik formation of Quaternary Age in northern Alaska. U.S.·Geological Survey. Prof. Paper 302-C, 59-91 pp . .........---.--.-' 1969. Biology, especially geomorphology, of northern Alaska. Arct1c 22:283-299. BLM, 1978. Draft environmental impact statement, proposed federal/state oil and gas lease sale Beaufort Sea. U.S. Department of the Interior, Washington, D.C., p. 166. , 1979. Final environmental impact statement: proposed federal, -:-st:;:-:a=t~e oil and gas lease sale, Beaufort Sea. U.S. Department of the Interior, Washington, D.C. , 1980. Final environmental impact statement proposed five-year "o=cs.----,lease sale schedule March 1980-February 1985. U.S. Department of the Interior, Washington, D.C. BNA, 1979. Environmental Protection Agency general provisions for effluent guidelines and standards. 40 CFR 401; 39 FR 4532, Feb. 4, 1974; as amended by 41 FR 17389, April 26, 1976; 44 FR 44502, July 30, 1979. Published by the Bureau of National Affairs, Washington, D.C. 8-4 Brent, S.M., and R.M. Goldberg (Eds.), 1970. The Alaska survey and report. The Research Institute of Alaska, Inc. in conjunction with the Anchorage Daily News. Vol. 1, 441 pp. and Vol. 2, 261 pp. Brewer, M.C., 1958. The thermal regime of an arctic lake. American Geophysical Union Transaction, 39 (2):278-284. Broad, A. C., 1977. Environmental assessment of selected habitats in the Beaufort and Chukchi Sea 1 ittoral system. In: Environmental assessment of the Alaskan continental shelf, annual report. OCSEAP, Boulder, Co. , H. Koch, D.T. Mason, G.M. Petrie, D.E. Schneider, and R.J . .,.,T-ay....,lr-o-r-, 1978. Environmental assessment of selected habitats in the Beaufort Sea 1 ittoral system. In: Environmental assessment of the Alaskan continental shelf. Annual report. NOAA, Boulder, Co. 86 pp. Brower, C.D., 1960. 50 years below z~ro: a lifetime of adventure in the far north. In collabration with P.J. Farrely and L. Anson. Dodd, Mead Co., New York. , W.A. and H.W. Searby, 1977. Climatic atlas of the outer ---;-....-. cont1nental shelf waters and coastal regions of Alaska, vol III - Chukchi -Beaufort Sea. AEIDC, Anchorage, Ak. Brown, J. 1975. Ecological investigtions of the tundra biome in the Prudhoe Bay region, Alaska. Biol. Papers Univ. of Alaska, Spec. Report No. 2, Fairbanks. , S.L. Dingman and R. Lewellen, 1968. Hydrology of a drainage .,---.---basln on the Alaskan coastal plain. U.S. Army Cold Regions Res. and Engineering Lab., CRREL Research Report 240. Burch, E.S., Jr., 1975. Eskimo kinsmen: changing family relationships in northwest Alaska. West Publishing Co., New York. 352 pp. Burns, J.J. (ADF&G), 1980. Personal communication to J. Hemming, Dames & Moore. Burns, John J., and Samuel J. Harbor, Jr., 1972. An aerial census of ringed seals, northern coast of Alaska. Arctic 25(4):279-290. Burrell, D.C., 1976. Natural distribution of trace heavy metals and environmental background in three Alaska shelf areas. NOAA/BLM-OCSEAP, Boulder, Co. , J.A. Dygas, and R.W. Tucker, 1975. Beach morphology and sedi---,--mentology of Simpson Lagoon. In: Environmental studies of an arctic estuarine system--final report. Institute of Marine Science, Report R74-1, University of Alaska, Faribanks, Alaska, pp. 45-144. 8-5 • Bursa, A., 1963. Phytoplankton in the coastal waters of the Arctic Ocean at Point Barrow, Alaska. Arctic 16:239-262. Bush, Ronald C., 1977. Plant and equipment noise treatment. Presented to Pacific Coast Electrical Association Engineering and Operating Conference, March 17-18, Los Angeles, CA. Bushdosh, M., K. Tarbox, and G. Robilliard, 1979. Attraction of amphipods by baited traps. In: Environmental studies of the Beaufort Sea -winter 1979. Report prepared for Prudhoe Bay Unit by Woodward- Clyde Consultants, Anchorage, AK. Cameron, R.D., 1979. Personal communication to J. Morsell, Dames & Moore. ' 1980. Personal communication to J. Morsell, Dames & Moore. -- , and K.R.· Whitten, 1976. First interim report of the effects of =th;-e'--;-trans-A 1 ask a pipe 1 ine on caribou movements. Joint St ate/Federa 1 Fish and Wildlife Advisory Team Special Report No. 2, 53 pp. , and K.R. Whitten, 1977. Second interim report of the effects -of~t~he trans-Alaska pipeline on caribou movements. Joint State/Federal Fish and Wildlife Advisory Team Special Report No.8, 44 pp.· , and K.R. Whitten, 1978. Third interim report of the effects of "'l"'1thr-e---;otrans-Alaska pipeline on caribou movements. Joint State/Federal Fish and Wildlife Advisory Team Special Report No. 22. ; and K.R. Whitten, 1979a. Seasonal movements and sexual segre- -g--;at-.i-on of caribou determined by aerial survey. J. Wildlife Manage. 43(3): 626-633. , and K.R. Whitten, 1979b. Distribution and movements of caribou ...... in-r-elation to the Kuparuk development area. Fist interim report. Alaska Dept. Fish and Game. 32p. , K.R. Whitten, W.T. Smith and D.O. Roby, 1979. Caribou distri- -r-6--,ut.--i.-on and group composition associated with construction of the trans-Alaska pipeline. Canadian Field Naturalist 93(2):155-162. Canadian Department of Fisheries and Environment, 1977. Artificial islands in the Beaufort Sea, a review of potential environmental impacts. Fisheries and Marine Service, Winnipeg. 41 pp. Cannon, P.J., 1977. The environmental geology and geomorphology of the barrier island-lagoon system along the Beaufort Sea coastal plain from Prudhoe Bay to the Colville River. BLM/NOAA-OCSEAP, Boulder, Co • 8-6 , and S.E. Rawlinson, 1978. The environmental geology and geo- -mo_r_p,-hology of the barrier island -lagoon system along the Beaufort Sea coastal plain from Prudhoe Bay to the Colville River. Annual P.I. reports, environmental assessment of the A 1 ask an continental shelf, Vol. X, transport, NOAA/BLM, Boulder, Co. Capuzzo, J.M., J.A. Davidson, and S.A. Lawrence, 1977. The differential effects of free and combined chlorine on juvenile marine fish. Estuarine and Coastal Mar. Sci. 5:733-741. , S.A. Lawrence, and J.A. Davidson, 1976. Combined toxicity of 7fr_e_e_ chlorine, chloramine and temperature to Stage I 1 arvae of the American lobster, Homarus americanus. Water Res. 10:1093-1099. Carey, A.G., ~r., 1977. 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Prepared by Waterflood Task Force . - 8-28 a z c > a: c en en 0 ..I " Algae - A 11 uv i urn - Amphipod - Anadromous - Applicant - Aquifer - Barrier island Bathymetry - Benthos - Bergy bit - Biocide - Biofouling - Biota - Cartridge filter - CHAPTER 9.0 GLOSSARY Nonvascular aquatic plants such as sea- weeds and kelps. Deposits of sediment and detritus by a river or stream, such as those forming a delta. A small crustacean usually having a strongly arched back and enlarged hind legs for jumping, e.g. beach fleas. Fish that ascend rivers from the sea to breed and/or overwinter. Sohio Alaska Petroleum Company and ARCO Oil and Gas Company, representing all the working interest owners of the Prudhoe Bay Unit. A water-bearing layer of rock. An island located close enough to a coast- 1 ine to shelter it from offshore storms. The pattern of water depths in a sea or lake. Organisms 1 iving on or in the sediments (or other bottom substrates of aquatic habitats). A piece of floating ice, generally not more than 10m in diameter. A substance lethal to 1 iving organisms, usually 1 imited to substances made or introduced by man. Encrustation of submerged structures by attached organisms. The set of living animals (fauna) and p 1 ants ( f 1 or a) found i n a h ab it at or environment. Replaceable, disposable filter element made out of materials such as paper, fiberglass, etc. 9-1 Chemosynthesis - Clastic sediment - Coagulant - Copepod - Crustacean - Cumulative Impact - Decibel Delta - Demersal - Detritus - Diatom - Drogue - Easterly - Ecosystem - The production of food through the use of chemically bound (as opposed to solar) energy. A sediment derived from the fragmentation of rock. A substance which promotes the cohesion of fine particules into large particules. Also flocculant. A minute crustacean with very long antennae; a dominant animal in the zoo- plankton. An aquatic animal characterized by joint legs and a hard shell (phylum Crustacea), e.g. crabs, isopods, amphipods and mysids. The impact on the environment that results from the incremental impact of the act ion when added to other past, present, and reasonably foreseeab 1 e future actions regardless of what agency or person under- takes such other actions. A unit of sound intensity relative to the least perceptible sound and to the average pain threshold. A deposit of alluvium at the mouth of a river. Living in close association with, but usually not restricted to, the bottom of a lake or sea (e.g., bottomfish). A loose deposit of primarily organic material. A unicellular plant having a siliceous shell. A capsule or float set adrift to track current flow. From the east. An integrated set of organisms and their ·nonliving environment which functions more or less as a unit. 9-2 Entrainment - Entrapment - EPA - Epibenthos - Epifauna - Epontic - Environment - Fast ice - Fauna - Flagellate- Floccul ant - Flora - Fouling organism- Frazil ice - Gyre - Halogen - Incorporation of small organisms into a filtered stream of water entering an intake structure. Capture of organisms by a stream of water such that they cannot or wi 11 not avoid being drawn into an intake structure. The U.S. Environmental Protection Agency. Organisms living on the bottom in aquatic habitats. - Animals living on a substrate in an aquatic habitat (see also epibenthos). Living on or in the undersurface of sea ice. The natural and physical environment and the relationship of the people with that environment. Ice which forms along the shoreline annually and is attached to the shore. Also landfast or shorefast ice. The set of animals 1 iving in a habit at or environment. · A unicellular organism having a whip-like locomotory structure. See coagulant. The set of plants 1 iving in a habitat or environment. See Biofoul er. Fine spicules or plates of ice in suspen- sion in water. A circular or spiral pattern of horizontal water movement. Any of the five elements fluorine, chlo- rine, bromine, iodine, and astatine. 9-3 Holoplankton - Ice gouging - Ice shove - Impingement - Infauna - Interstitial water Invertebrates - Isopod - Icthyoplankton - Kelp - Laminarian kelp - Larva - Littoral - Organisms that live suspended in the water throughout their life cycles (see also plankton, meroplankton). Slicing cuts in the sea floor made by the rough bottom surfaces of ice masses as they drift into shallow water. Also ice scoring. Pushing of sediment along a broad front by movement of ice in contact with the bottom. Also ice push. Contact or capture of aquatic organisms by a screen or filter as water is drawn into an intake structure. Animals living in a substrate in an aquatic habitat-,-e.g. clams, worms. Water found between the grains in a sediment, such as sand grains on a beach. Animals lacking vertebrae or spinal columns. A small flattened crustacean belonging to the order Isopoda, e.g. pillbug. Fish. A very large brown algae common in shallow water in cold seas. A brown alga belonging to the genus Laminari a. An embryo that differs markedly in appear- ance from its parents and becomes self- sustaining before assuming the physical appearance of its parents. The concentration of a toxic substance lethal to 50 percent of the exposed test animals during a fixed time interval, typically 48 or 96 hours. A nearshore aquatic habitat strongly affected by changing tide levels and breaking waves. Also intertidal. 9-4 · Littoral drift- Macroalgae - Macrobenthos - Macroinvertebrate - Media filter - Merop 1 ankton - Motile- Mys id -. Nekton - Neritic - Nested basins - Nutrient - Pack ice - PCB - Pelagic - Penn ate diatom - The longshore movement of sediment by nearshore processes, such as breaking waves. Large aquatic ·plants easily visible to the unaided eye. The largest bottom dwelling organisms, typically those larger than 0.5 mm. A 1 arge invertebrate, see also inverte- brate, macrobenthos. Bed of graded material such as sand and gravel of increasing size in the direction of flow. Organisms that spend only a portion of their life cycle suspended in the water. Able to move under its own power. A small, shrimp-like crustacean. An animal that 1 ives in the water column and is able to swim against a 1-knot current, e.g. adult fish. Portion of an ocean near a continent, characterized by a water depth·of less than 200 m. Lake basins positioned one within another or intersecting and formed at different times. A substance which is used as a food or in the product ion of food, such as nitrate and phosphate. · Large ice masses adrift in the Arctic Ocean (see also fast ice). Polychlorinated biphenyl, a chlorinated organic compound. Living in the water column, as opposed to benthic. Unicellular plant belonging to the order Pennales. 9-5 • Period (wave) - pH - Photosynthesis - Physiographic province - Phytoplankton - Plankton - Polychaete - Precoat-type filter - Primary producer - Pycnocline - Relic - Salinity- Salmonid - Sessile - Shoaling - Shove - See wave period. A measure of the acidity (low pH) or alkalinity (high pH) of a solution where 7 is neutral on a scale of 0 -14. Production of food through the use of solar energy. A geographic region defined on the basis of its similar physical structure. Plants suspended in the water column (see also plankton). Organisms 1 iving suspended in the water column that are unable to swim against a 1-knot current (see also nekton). A roundworm belonging to the Class Poly- chaeta. Filter medium which supports a coating material such as diatomaeous earth, bentonite, or other material. When loaded with sol ids filtered from the water, filter is backwashed removing both solids and precoat material. An organism that produces its food dir- ectly through photosynthesis or chemo- synthesis. A sharp density gradient in the water column, which resists vertical mixing. A small remnant of a previously extensive habitat or population. A measure of the concentration of dis- solved salts in water. Fish belonging to the family Salmonidae, such as salmons, ciscoes, whitefish and trouts. Attached to a firm substrate, as opposed to motile. Becoming shallower. See "ice shove". 9-6 ' :~ Spoil Storm surge - Subtidal - Terrigenous Total organic carbon - Trace element - Transmissivity - Tundra - Turbidity - USFWS - Water column - Wave period - Westerly - Wet 1 and - Zooplankton - The material that is removed by dredging. A storm-generated force which is trans- mitted through the water column and exerts a frictional stress on the sea floor. Below the level of the lowest tidal height. Originating on land. Carbon bound in organic molecules in dissolved, particulate and volatile forms. An element, e.g. mercury, that is rare in nature but may serve important _func- tions. The degree to which 1 ight passes through water without being deflected or absorbed by dissolved or suspended matter. A terrestrial habitat type characterized by lichens, mosses, low shrubs, and an absence of trees. Cloudiness or lack of clarity in water (see also transmissivity). The U.S. Fish and Wildlife Service. An imaginary vert ica 1 profile through an aquatic habitat. The time interval between the passage of successive waves past a fixed object. From the west. An area inundated or saturated by water that typically supports vegetation adapted to saturated soil conditions, such as a swamp, marsh or bog. Animals 1 iving suspended in the water column (see also plankton). 9-7 ACMP - ADEC - ANCSA - ASNA - ASRC - bbl - BOD - c - CCP - CEQ - em - cm2 - C02 - COD - CRREL - d - dB - DEW - DH 1 - DH 2 - DH 3 - DO - EIS - ACRONYMS AND ABBREVIATIONS Alaska Coastal Management Program Alaska Department of Environmental Conservation Alaska Native Claims Settlement Act Arctic Slope Native Association A ret i c Slope Region a 1 Corporation barrels biochemical oxygen demand Celsius Central Compressor Plant Council on Environmental Quality centimeters square centimeters carbon dioxide chemical oxygen demand U.S. Army Cold Regions Research and Engineering Laboratory day decibels Distant Early Warning Dock Head 1 Dock Head 2 Dock Head 3 dissolved oxygen environmental impact statement 9-8 EPA - F - ft - ft3 - FWS - gal - GC 3 - ha - hp - hr - Hz - in - i n2 - INSTAAR - kg - km - km2 - km3 kt - 1 - lb - Leq - m - m3 - mg - .. ~ ;~ ~: :::: it '·' ,. t -~. r ~ ~ : ·. Environmental Protection Agency Fahrenheit feet cubic feet U.S. Fish & Wildlife Service ga 11 ons Gathering Center 3 hectares horsepower hours cycles per second inches square inches Institute of Arctic and Alpine Research kilograms kilometers square kilometers cubic kilometers knots 1 iters pounds equivalent pound level meters cubic meters milligrams 9-9 mi - min - mm - mph - NAAQS - NEPA - NMFS - NOAA - NPDES - NPRA - NSB - OCSEAP - O&M - PBU - ppb - ppm - ppt - PSD - s - SGCP - TSS - miles square miles cubic miles minutes millimeters miles per hour National Ambient Air Quality Standards National Environmental Policy Act of 1969 National Marine Fisheries Service National Oceanic and Atmospheric Administration National Pollutant Discharge Elimination System National Petroleum Reserve -Alaska North Slope Borough Outer Continental Shelf Environmental Assessment Program operation and maintenance Prudhoe Bay Unit parts per billion parts per million parts per thousand Prevention of Significant Deterior- ation seconds sales gas conditioning plant total suspended solids 9-10 J.Jg/m3 USGS - vs - WODNWR - yd3 - yr - < > H .• ..,. ~· . l (_; r ~-- micrograms per cubic meter United States Geological Survey versus William 0. Douglas National Wildlife Range cubic yards years 1 ess than greater than 9-·11 CHAPTER 10.0 INDEX Abandonment, Project: 2-61, 2-93, 4-27 Accidents: (see Petroleum Products Spills and Saltwater Spills) ACMP Conformance: 4-9, 4-10, 4-15, 4-16, 4-17 Acoustics: Appendix G Aesthetic Values: 3-33, 3-101, 4-20 Air Emissions: 2-40, 2-41, 2-44, 2-49, 2-52, 4-73, 4-82 Air Quality: 3-69 Monitoring Programs: 4-84 National Ambient Air Quality Standards (NAAQS) Permit Review: 3-66, 4-84 Prevention of Significant Deterioration (PSD) Review: 4-73, 4-74, 4-82, 4-83 Alaska: (see also Statewide) Alaska Coastal Management Act: 3-10, 4-14 Alaska Coastal Plan: 3-21, 3-31, 3-86 Alaska Department of Fish and Game: 2-74 A 1 ask a Department of Natura 1 Resources: 3-86 Alaska Native Claims Settlement Act of 1971: 3-6, 3-76, 3-80 Alaska Oil and Gas Conservation Commission: 2-8, 2-11 Alaska Statehood Act (1959): 3-6, 3-75 Alaska Water Quality Standards: 4-46, 4-50 Alternative A Description: 2-61, 2-62, 4-8, 4-15 Environmental Impact: 4-12, 4-22, 4-44, 4-54, 4-65 Alternative B Description: 2-62, 2-66, 4-8, 4-15 Environmental Impact: 4-43, 4-51, 4-63, 4-74 Alternative C Description: 2-62, 2-66, 2-67, 2-69, 4-15 Environmental Impact: 2-64, 2-66, 4-44, 4-45, 4-53, 4-63, 4-75 Alternative C-1: 2-69 Alternatives, Administrative Comparative Impacts: 2-2, 2-3 Delay Alternative: 2-2, 2-3, 2-5, 2-8 National Alternative: 2-10 No Action Alternative: 2-2, 2-5 Alternatives, Oil Recovery Enhancement: 2-11 Alyeska Pipeline Service Company: 3-4, 3-15 Anchor Ice: (see Ice) Angled Screen Intake Design: 2-77 Animal Nuisance: 4-26 Applicant's Proposal: 2-15, 2-17, Appendix B Aquifers: (see Groundwater Resources) Archaeology: (see Prehistory and Cultural Features) ARCO Oil and Gas Company: 1-1, 3-6, 4-79, 7-1 Arctic Coastal Plain: 3-1, 3-12, 3-23, 4-4 Arctic Fox: 3-27, 3-29, 3-32, 4-26 Arctic Slope Native Association: 3-77 Arctic Slope Regional Corporation: 3-77 Artificial Lift (Pumping) System: 3-92 Arctophila fulva: 3-26, 4-24 Bacteria: 3~ Backwash System: 2-20, 2-51, 2-78, 4-45, 4-49, 4-75 Ballast: 4-56 Barrier Effect: 2-27, 4-58, 4-62, 4-74 Barrier Island: 3-14, 3-25, 4-16, 4-17, 4-61 Barrier Island Migration: 3-14, 3-35, 3-37, 3-38 Base Camps: (see Land Use) Beach and Coastline: 4-17, 4-40 10-1 Benthic Algae: 3-51 Community: 2-84, 3-52, 4-60, 4-61, 4-71 Diatoms: 3-50 Habitat: (see also Marine Biology) 2-24, 2-34, 2-69, 3-37 Benthos: 2-26, 2-27, 2-38, 2-41, 2-52, 2-69, 2-82, 2-84, 2-92, 3-51, 3-52, 4-4, 4-34, 4-55, 4-56, 4-57' 4-62' 4-67' 4-75, 4-76 Bergman System: 3-26 Biocide: 2-29, 2-38, 2-51, 2-82, 4-2, 4-45, 4-49, 4-53, 4-60, 4-76, 4-77 Biofouling: 3-52, 5-1 . Biological Productivity: 2-94, 3-58, 4-2, 4-3, 4-4, 4-22, 4-32, 4-35, 4-62, 4-78 Biological Recolonization: 4-55, 4-64, 4-76, 5-3 Biological Sensitivity: 2-26, 2-43, 4-25, 4-29, 4-60, 4-80 Biota: 3-44, 3-58 Birds: 3-23 Attraction of: 3-26, 4-71 Breeding Grounds: 3-23, 4-7, 4-26 Collisions: 2-50, 2-90, 2-96, 4-2, 4-59 Consumers: 3-23 Habitat: 2-56, 3-23,. 3-26, 4-3, 4-4, 4-5, 4-24, 4-26, 4-62 Migrations: 2-50, 4-13, 4-26, 4-30, 4-55 Movements: 3-23, 3-92 Nesting: 3-26, 3-27, 4-20, 4-30 Predators: 2-36, 3-27 Shorebirds: 2-43, 2-50, 2-85, 3-2, ·3-23, 4-3, 4-4, 4-26, 4-55, 4-61 Staging Areas: 3-25 Summer Residents: 3-23 ·Waterfowl: 2-43, 2-50, 2-85, 2-96, 3-2, 3-23, 3-32, 3-99, 4-3, 4-4, 4-24, 4-26, 4-28, 4-30, 4-31, 4-33, 4-55, 4-61 Wetlands Habitat: (see also Wetlands), 3-25, 3-99 Winter Residents: 3-26 Blocking, Water Flow: (see Ponding and Blockage) Boundary Litigation: 4-14 Bowhead Whale: 3-56, 4-55, 4-90, Appendix E Breach Criteria: 2-73, 2-74 Impacts: 4-40, 4-58 Locations: 2-75 Breaching Designs: 2-75, 2-76, 2-83 Circular Metal Culvert: 2-75 Clear Span Bridge: 2-75, 2-77 Semi-elliptical Culvert: 2-72, 2-77 Canning River: 2-1, 3-1, 3-6, 3-25, 3-84, 3-97, 4-27, 4-30 Carbon Dioxide, Recovery: 2-11 Caribou Avoidance Behavior: 3-29, 3-99, 4-3, 4-26 Behavior: 4-91 Calving: 3-28, 3-99 D·istribution: 3-28 Habitat: 2-85, 3-32, 4-2, 4-4, 4-7, 4-18, 4-30 Migrations: 3-2, 3-28, 3-100, 4-27 Passage: 2-43, 2-46, 2-91, 4-30, 4-31 Cartridge and Precoat Filters: 2-14 Causeways, Additional 4-61, 4-62 Causeway Alternatives 2-16, 2-61 Breaching Designs (see Breaching Designs) Breaching Schemes: 2-66, 2-71, 2-95 Deeper Intake: 2-61 Integral Intake Configuration (see also Alternatives A, B, and C): 2-62 Remote Intake Design: 2-61, 2-63 Causeway Extension and Modification Description: 2-20, 2-22, 4-42 Environmental Impact: 2-24, 3-39, 3-52, 3-56, 4-2, 4-3, 4-39, 4-57, 4-59,.5-1 Caustic Flooding, Recovery: 2-12 Center Flow Screen Intake Design: 2-77 Centrifugation, Intake Wastes: 2-15 Chemical Additives: 2-29, 2-30, 2-47, 4-77 Chemical Reactions, Wetlands: 3-32 Chlorine Products: (see also Biocide) 2-39, 4-2, 4-49, 4-50, 4-51, 4-52, 4-69 Chlorine Dose: 4-50 Circulation: (see Currents/Circulation) Circulation Modeling Studies: 2-66, 2-71, 2-75, 2-83. 4-36' 4-37' 4-38' 4-59' 4-62' 4-64 Clean Air Act of 1977: 4-82 Clean Water Act of 1977: 1-1, 1-2, 3-30 Climatic Summary, Barter Island: 3-64 Coagulant: 2-34, 2-39, 2-82, 4-45, 4-51, 4-69, 4-71, 4-76 Coastal Policy: (see also Marine Sanctuaries) Buffer: 3-10 Council: 3-10 Mid-Beaufort Region District Plan: 3-10 Ordinance: 3-10 Zoning: 3-10, 3-29 Coastal Processes: Appendix I Coastline and Causeway Erosion: 2-24, 3-37, 3-40, 4-3, 4-17 Coastline Configuration: 3-14, 4-3 Co 1 d Regions Research and Engineering Laboratory, U.S. Army (CRREL): 3-23 Colville River: 2-1, 2-28, 2-36, 2-73, 2-77, 3-1, 3-6' 3-25' 3-27. 3-30, 3-54, 3-55, 3-91, 3-95, 4-27, 4-3D, 4-72 Construction Work Force: 2-59, 2-60, 4-78, 4-91 Cooperating Agencies: 6-3 through 6-8 Copepods: 3-50 Corps of Engineers: 1-1, 1-6, 2-1, 2-5, 2-17, 2-71, 2-95, 3-14, 3-23, 3-30, 3-31, 5-1 Cultural Features ~revious Archaeological Surveys: 4-93 Cumulative Impacts: S-1, S-8, S-9, 1-1, 2-1, 2-2, 2-3, 2-28, 2-36, 2-44, 2-56, 2-59, 2-67, 3-84, 3-85, 3-86, 3-87, 3·-88, 3-89, 3-90, 3-91, 3-92, 3-93, 3-94, 3-95, 3-96, 3-97' 3-98, 3-99, 3-100, 3-101, 3-102, 4-2, 4-4, 4-5, 4-6, 4-7, 4-8, 4-10, 4-11, 4-12, 4-14, 4-26, 4-27' 4-28, 4-30, 4-33, 4-34, 4-79, 4-80, 4-82, 4-84, 4-91, 4-95 Currents/Circulation: (see also Sediments, Impacts-Adverse, Circulation Modeling Studies, Storm Surges and Tides, Upper-ice Currents) 2-84, 3-34, 3-39, Appendix C, Appendix D Density Gradients: 3-35 Longshore Currents: 2-73, 3-39 Measurements: 3~35 Nearshore Currents: 2-62, 2-69, 3-35, 4-3 Patterns: 3-39, 4-44 Under-ice Currents: 3-34, 3-37, 4-44 Winds: 3-35 10-2 Deaeration: 2-82 Deaerator: 2-20, 2-29 DEIS Mailing List: 7-1 Detrital Accumulation: 4-57, 4-64, 4-72, 4-75 Diffuser: 2-37, 2-38, 2-84, 4-75 Discharge Effects: 3-39 Discharge, Emergency: (see Sea1~ater Discharge, Treated) Dissolved Oxygen: (see Water Quality) Dissolved Solids: (see Water Quality) Dock Head 3 "(DH 3): 2-14, 2-20, 2-21, 2-22, 2-24, 2-54, 2-63, 2-67, 2-71, 2-76, 2-78, 3-35, 3-36, 3-41, 3-50, 3-53, 4-39, 4-41, 4-44, 4-46, 4-48, 4-54, 4-58, 4-76 Domestic Waste: 2-52, 4-49, 4-79 Drainage Pattern, Surface: 2-43, 2-47, 2-92, 3-18, 3-26, 3-32, 3-99, 4-3, 4-20, 4-24, 4-28, 4-32, 4-33, 4-78, 4-79 Dredged Channel: 4-9 Dredging: 2-37, 2-62, 4-75 Alternatives: 2-84 Description: 2-41, 2-67, 4-63 Disposal Areas: 2-84 Environmental Impacts: 2-34, 2-41, 2-67, 3-39, 4-44, 4-52, 4-54, 4-55, 4-75 Methods: 2-78 Drilling Fluids and Cuttings: 2-52 Dust: 2-38, 3-26, 3-99, 4-2, 4-4, 4-24, 4-28, 4-30, 4-32, 4-33, 4-78, 4-79, 4-82 Earthwork: 4-20 Economies: (see Project Benefits) Effluents Composition: 2-35, 2-37 Diffuser Design: 2-38 Dilution Factor: 4-46 Flow Rate: 4-45 Holding Ponds: 4-81 Recirculation: 4-51, 4-52, 4-76 Emissions: (see Air Emissions, Exhaust Emissions, Dust, or Sound) Emergency Dump Pit: 2-46, 2-51 Emp 1 oyment: (see Manpower Requirements, and Population and Employment) Epifauna: (see Benthos) Endangered or Threatened Species: 2-4, Appendix E, Appendix N Bowhead Whale: 3-56, Appendix E Gray Whale: 3-56 Peregrine Falcon: 3-26 Thalaspi arcticum: 3-22, 4-24, Appendix L Endangered Spec1es Act: 3-22 Entrainment: (see Impingement, Entrainment and Entrapment) Entrapment: (see Impingement, Entrainment and Entrapment) Environmental Impact, Significant Issues: 1-1 Environmental Impact Statement Purpose and History: 1-1 Environmental Profiles, Future Aesthetics: 3-100 Benthos: 3-99 Caribou: 3-100 Inupiat Culture: 3-100 Marine Area: 3-99 Marine Mammals: 3-99 Road Activity: 3-100 Terrestrial Activity: 3-99 Waterfowl: 3-99 Water Quality: 3-100 Wet 1 ands: 3-98 Wilderness Values: 3-106 Environmental Protection Agency: 1-1 Environmentally Preferred Plan: 2-16, 2-95 Eskimo Cu 1 ture: (see Inupi at) Exhaust Emissions: 4-82 Facilities Location, Alternatives: 2-16, 2-17, 2-18 Fairbanks Environmental Center: 3-13 Filter, Backwash System: (see Backwash System) Filter, Seawater: 2-24, 2-34 Fish: 3-51, Appendix E Attraction of: 2-36, 2-38, 2-71 Arctic Char: 2-27, 3-2, 3-52, 3-53, 4-58, 4-59, 4-72, 4-73, 4-74 Arctic Cisco: 2-27, 3-2, 3-52, 3-54, 4-72 Arctic Cod: 2-34, 3-52, 4-55, 4-61, 4-65, 4-66, 4-67, 4-68, 4-74 Bartail Snailfish: 3-52, 4-57, 4-66, 4-67 Capelin: 3-53 Entrainment: (see Impingement and Entrainment) Fourhorn Sculpin: 3-53, 3-54, 4-57, 4-65, 4-66, 4-67 Habitat: 2-96, 3-32, 4-4, 4-7, 4-61, 4-77 Impingement: (see Impingement and Entrainment) Least Cisco: 3-52, 3-54, 4-58, 4-59, 4-72 Life Histories: 3-59 Migrations: 2-4, 2-27, 2-36, 2-66, 2-69, 2-71, 2-75, 3-2, 3-54, 3-55, 3-58, 4-2, 4-7' 4-13, 4-57' 4-58, 4-61, 4-62, 4-63, 4-65, 4-72, 4-73, 4-74 Ninespine Sticklebacks: 3-58 Nursery Areas: 4-57 Overwintering Habitat: 2-94, 3-54, 3-58, 4-72, 4-77 Pacific Sandlance: 3-53 Removal System, High· Velocity: 2-78, 4-77 Whitefish: 2-27, 2-74, 3-2, 3-54, 4-58, 4-59, 4-72 Fisheries, Commercial ·and/or Sport: 3-52, 3-54, 3-56, 4-14 Flow Blockage: (see Ice) Food Resource Distribution: (see Impacts, Cumulative) Food Webs: 2-96, 3-32, 3-52, 3-53, 3-56, 4-33, 4-56 Frazi 1 Ice: (see Ice) Friends of the Earth, Inc.: 3-12 Freeze Protection: (see Low-Pressure Pipeline and High-Pressure Pipeline) Freshwater Resources: Appendix F Construction Impacts: 4-77 Description: 3-57 Flow: 3-54 Operation Impacts: 4-79 Reservoir Capacity: 4-78 Use: 4-79 Fuel and Power System Alternatives: 2-90, 2-95 Description: 2-47, 4-42 Environmental Impact: 2-50 Fuel Consumption: 1-2, 4-4 Fuel Spills: (see Petroleum Product Spills) Future Oil and Gas Developments: 3-85, 3-86, 3-87 Alaska Highway Natural Gas Pipeline: 3-91, 4-92 ALPETCO Refinery: 4-92 Canadian Projects: 3-98 Duck Island Offshore: 3-91, 3-95 10-3 Gwydyr Bay and Stump Island: 3-94, 3-95 Kuparuk Field: 3-95 NPR-A and WODNWR: 3-94, 3-95 Point Thomson Offshore: 3-90, 3-95 Sales Gas Conditioning Plant: 3-70, 3-91, 3-94, 4-84, 4-92 Second Beaufort Sea Oil and Gas Lease Sale: 3-91, 3-96 Future 1~ithout the Project: 3-89 Gas Injection, Recovery: 2-11 Geology and Soils: (see also Gublik Formation, Offshore Bottom Material) Construction Impacts: 4-17 Description: 3-12 Operation Impacts: 4-20 Gravel: (see also Rehabilitation Measures) Alternative: 2-66 Berm: 2-88 Description: 2-56, 2-66 Environmental Impacts: 2-56, 4-3, 4-28, 4-78 Extraction: 2-56, 3-14, 4-16, 4-22, 4-55, 4-81 Requirements: 2-57, 2-67, 2-69, 2-89, 4-17, 4-63 Restoration: 2-94, 4-22 Sources: 2-56, 2-58, 2-92, 3-17, 3-18, 4-17, 4-78 Gravel and Insulation: 2-91, 4-18, 4-19, 4-27 Gravel Island: 2-62, 2-67, 2-95, 3-44, 4-16 Ground Motion Parameters: 3-15 Groundwater Resources: 3-60 Accidents: 4-81 Aquifers: 3-62 Construction and Operation Impacts: 4-80 Quality: 3-62, 4-80 Sources: 3-61 Temperatures: 3-60 Gubik Formation: 3-14 Habitats: (see also Vegetation, Wetlands, Benthic Habitat, Barrier Islands) Aquatic: (see Freshwater Resources) Barrier Islands: 3-21 Gravel Fill Areas: 3-21, 3-97 Lichens: 3-21 Marine: (see Marine Biology) Moss: 4-28 Salt Marsh/Beach Zone: 3-21, 4-28, 4-29 Sedges/Grasses: 2-44, 3-21, 4-28, 4-29, 4-80 Stream: 2-47 Wet Tundra: 3-20, 3-26, 4-3, 4-4, 4-29 Woody Shrubs: 2-44, 3-21, 4-28 Other: 2-4, 3-22 Habitats, Impacts on: (see Impacts, Adverse) Habitat Evaluation Procedure: 4-24, Appendix L Habitat Mapping: 2-94, 3-26, Appendix L Habitat Standard, ADF&G: 4-14 Habitat Values: 2-4, 2-43, 2-46, 2-94, 3-99, 4-25, Appendix L Harrison Bay: 3-34 Heave and Settlement: 4-21 High Pressure Pipeline: (see also Pipeline Con- struction Mode) Construction Alternative: 2-88, 2-89 Description: 2-20, 2-46 Environmental Impacts: 2-46, 4-29, 4-90 Freeze Protection: 2-46, 2-50, 2-51, 2-90 History: 3-3 Holoplankton: 3-50 Hydrocarbons Formation: 3-16 Reserves, Gas: 3-16 Reserves, Oil: 3-15 Hydrodynamic and Water Quality Models: (see Modeling) Hydrology: (see also Drainage Pattern and Nutrient Release) Drainage Patterns: 3-32 Nutrient Release: 3-32 Storage Function: 3-32 Subsistence and Recreational Use: 3-33 Ice: (see also Permafrost) Anchor Ice: 3-46, 3-49 Blockage: 2-29, 4-52 Embankment Stability: 4-42, Appendix J Floes: 3-45 Forces: 2-24, 2-29, 2-62, 2-69, Appendix J Frazil Ice: 2-29, 3-46, 4-52, 5-1 Gouging: 2-67, 2-85, 3-40, 3-46, 4-41, 4-43, 4-44, 4-56, 4-64 Keel Scoring: 2-62 Movement: 3-45, 4-41 Over-riding: 2-62, 3-46, 4-42, 4-44, 5-1, Appendix J Permanent Ice Pack: 3-35 Polar Pack: 3-45, 3-46, 3-48 Pressure Ridge Remnants: 3-45. Processes: 3-15 Sea Ice: 3-44 Sea Ice Level: 5-1 Shorefast-Bottom: 3-44, 4-64 Shorefas t-Fl oat i ng: 3-44, 3-45, 3-46, 3-47 Stress Effects: 4-57, 4-58 Transition: 3-45 Under Water Ice: 3-46 Wedge Polygons: 3-16, 3-21, 4-13 Ice Algae: 3-50, 4-71 Icthyoplankton: 2-36, 3-50, Appendix E Impacts, Adverse -Summary: 4-1 Impacts, Beneficial: (see Project Benefits) Impacts, Comparison of: 2-2, 2-3, 4-12 Impingement, Entrainment and Entrapment: 2-29, 2-34, -2-36, 2-66, 2-77, 2-83, 2-96, 3-53, 4-2, 4-4, 4-20, 4-65, 4-68, 4-72, 4-74, 4-76, 5-1, 5-3, Appendix H In-Situ Combustion, Recovery: 2-13 Incineration of Slurry: 2-81 Infauna: (see Benthos) Injection Plant Alternatives: 2-89 Description: 2-20, 2-29, 2-44, 2-45 Environmental Impact: 2-44, 2-52, 4-30, 4-90 Injection Site Facilities Description: 2-46 Environmental Impact: 2-47, 4-90 Injection Wells: 2-46, 2-48, 2-49 Injection Wells Freeze Protection: 2-91 Insulation and Gravel: (see Gravel and Insulation) Intake, Seawater: (see Seawater Intake) Intake Screen Finer Opening: 2-77 Interim Zoning Ordinance: (see North Slope Borough) Inupiat Eskimo: (see also Subsistence) Land Use: 3-4, 4-7 Life Styles: 2-96, 3-4, 3-75, 3-101, 4-2, 4-7, 4-93 Invertebrates: 2-28, 3-26, 3-50, 4-65 Aggregations: 2-39, 3-100 Community: 3-32, 3-50, 3-59, 4-33, 4-61 Jet Pump Return System: 2-77 Jones and Return Island Group: 3-14, 3-37, --Appendix C 10-4 Kelp, Impacts on: 4-56, 4-71 Kuparuk Field: 2-88, 3-90, 3-95 Kuparuk River: 2-1, 2-26, 3-1, 3-16, 3-25, 3-52, 3-58, 3-59. 3-66, 4-27. 4-41, 4-56, 4-62, 4-72, 4-77, 4-80 Kuparuk River Formation: 3-16 Labor Supply and Services: 2-59 Alternative: 2-92 Construction Work Force: 2-59, 2-60 Craft Labor: 2-59 Economic Effects: 2-61 Manpower Requirements: 2-59 Operations Work Force: 2-59 Purchases: 2-59. Recruitment Practices: 2-59 Land: (see Private Lands and State Lands) Land Status Federal: 3-6 North Slope Borough: 3-6, 3-9 North Slope Region: 3-8 State: 3-6 Land Use: 3-4 Base Camps: 3-6 Construction Impacts: 4-13 Facilities: 3-7, 4-13 Operation Impacts: 4-16 Village: 3-4, 3-7 Land Use Planning: 3-10 Landfill Capacity: 2-52, 2-81 Landfill Operations: 4-81 Licenses, Permits and Approval, Status of: 1-5 Life Styles North Slope Communities: 2-96, 4-7, 4-95 Statewide: 4-95 Liquid Waste: 4-79 Lisburne Formation: 3-16, 3-88 Littoral Drift Rates: 3-37 Low-Pressure Pipeline Accidents: 2-43 Alternative: 2-16, 4-2~ Construction: (see Pipeline Construction Mode) Description: 2-20, 2-29, 2-41, 2-42, 2-66, 4-42 Environmental Impacts: 2-43 Freeze Protection: 2-29, 2-41, 2-50, 2-90, 2-94 Routing: (see Pipeline Routing) Low-Pressure Separation System: 3-93 Macroalgae: 3-50 Maintenance Dredging: {see Dredging) Manpower Requirements: 2-60, 4-91 Mammals: {see Caribou, Arctic Fox, Polar Bear and Marine Mammals, Appendix E) Marine Biology: (see also Marine Mammals, Appendix E) Attraction of Organisms: 2-34, 2-38, 4-55, 4-57, 4-64, 4-71 Benthos: 3-51, 4-64 Birds: 3-99 Construct ion and Operation Impacts: 3-99, 4-1, 4-2, 4-56, 4-64, 4-66 Fish: 3-51 through 3-56, 3-92 General Ecology: 3-49 Marine Mammals: 3-56, 3-92 Primary Producers: 3-50 Zooplankton: 3-50 Marine Biology Construction Impacts Alternative A: 4-54 Alternative B: 4-63 Alternative C: 4-64 • Marine Biology Operation Impacts Accidents: 4-77 Alternative A: 4-64, 4-65 • Alternative B: 4-66, 4-74 Alternative C: 4-66, 4-75 Marine Cultural Resource Survey: {see Cult~ral Features) Marine Life Return Line: 2-20, 2-29, 2-34, 2-38, 2-83 Attraction of Scavengers: 2-39 Description: 2-39, 2-40, 2-66, 2-78, 4-65, 4-75 Marine Mammals: {see also Arctic Fox and Polar Bear) 3-56, Appendix E Bearded Seals: 2-36, 3-56, 3-57, 4-56 Belukha Whale: 3-56, 4-56 Bowhead Whale: 3-56, 4-56, 4-90 Development Impact: 3-99, 4-4 Gray Whale: 3-56 Polar Bear: 3-56, 3-59 Ringed Seals: 2-36, 3-56, 3-57, 4-56 Sounds, Impacts of: 4-90 Marine Sanctuaries: 3-13 Mechanical Abuse: {see Plankton Impacts) Meroplankton: 3-50, 4-67 Meteorology: {see also Air Quality) 3-66 Air Quality: 3-66 Construction Impacts: 4-81 Operation Impacts: 4-82 Precipitation: 3-1, 3-62 Temperature: 3-62 Wind: 3-62, 3-63, 3-64, 3-65 Micellar Solution Flooding: 2-12 Midway Islands: 3-50 Migration Barrier: 4-2 Mineral Resources Hydrocarbons: 3-15 Sand and Gravel: 3-16 Mitigative Measures: 2-93 Bubble Curtatn; 2-93 Drainage Readjustment: 2-94 Fine-Mesh Diversion: 2-93 Fish Guidance: 2-93 Ice Over-ride Protection: 2-95 Low-Pressure Pipeline Emergency Discharge: 2-94 Over-ice Discharge: 2-94 Procedural Measures: 2-95 Restoration of Gravel Removal Areas: 2-94 Wetlands Conservation: 2-94 Mixing: {see Water Quality) Mixing Zone: 2-38, 2-81, 2-84, 4-2, 4-46, 4-48, 4-50, 4-52, 4-53 Modeling Prudhoe Bay: Appendix D Simpson Lagoon: Appendix D Monitoring Programs, Potential Accidents: 5-14 ' Air Quality: 4-82 NPDES Compliance: 5-1, 5-2 Project Performance and Engineering: 5-1 PSD Compliance: 5-1, 5-2 Municipal Entitlement Act: 3-6 Municipal Entitlements: 3-11, 4-14 National Ambient Air Quality Standards {NAAQS): {see Air Quality) National Energy Production, Effects on: 1-2, Appendix M National Environmental Policy Act of 1969: 1-1, 1-2 National Marine Fisheries Service {NMFS): 1-1, 2-4, 4-55 10-5 National Oceanic and Atmospheric Administration {NOAA): 3-13 National Petroleum Reserve, Alaska {NPR-A): 3-3, 3-4 Native Claims Settlement Act: {see Alaska Native Claims Settlement Act) Natura 1 Resources: {see Resource Commitments) Naval Petroleum Reserve Number 4: {see National Petroleum Reserve -Alaska) Near-field Dilution: {see Effluents) Near-field Mixing Zone: {see Mixing Zone) Nearshore Currents: {see Currents/Circulation) Niakuk III: 3-37, 3-39 Noise: {see Sound) North Slope Demographic Composition: 3-76, 3-77, 3-78 Economy: 3-79 Employment Patterns: 3-76, 3-79, 4-91, 4-94 Labor Force: {see also Population and Employ- ment): 3-76, 3-80 Local Taxation: 3-79 North Slope Borough: 3-6, 3-77 Budget: 3-80 Interim Zoning Districts: 3-12 Interim Zoning Ordinance: 3-10, 4-9 Property Tax Revenue: 3-80, 4-1, 4-93, 4-94 North Slope Development Projects: 4-5 North Slope Social Features Political Development: 3-75 Subsistence: 3-73 NPDES Application: 2-39, 5-1, Appendix 0 Nursery Areas: {see Fish) Nutrients: {see Wate.r Quality and Wetlands) Nutrient Flow: {see Wetlands) Nutrient Release: 3-21~ 3-31, 3-32 Oceanographic Construction Impacts Accidents: 4-44 Alternative A: 4-35 Alternative B: 4-43 Alternative C: 4-44 Oceanographic Operation Impacts Accidents: 4-52 Alternative A: 4-44 Alternative B: 4-52 Alternative C: 4-52 Oceanography, Physical and Chemical: 3-33, 4-34, Appendix C Offshore Bottom Material: 3-14, 4-17 Offshore Islands: {see Barrier Islands) Offshore Permafrost: {see Permafrost) Oil Distribution: 4-4 Oil Production Scenarios, Recovery Alternatives: 2-6 Oil Reservoir Dynamics: 2-89, 5-1 Open Pits: {see Settling Ponds) Operations Work Force: 2-59, 4-79, 4-94 Outfall Pipelines: {see also Diffuser and Marine Life Return Line) Alternative: 2-69, 2-84, 2-95 Description: 2-20, 2-29, 2-37, 4-75 Environmental Impacts: 2-38 Flow Rate: 2-37 Mechanical Stress: 2-39 Operation: 2-83 Over-Ice Discharge: 2-82, 2-94 Pad and Road Construct ion: .{see Road and Pad Construction) Peregrine Falcon: 3-26, 3-32 Permafrost: 3-37 · Onshore: 2-47, 2-81, 2-91, 3-1, 3-16, 3-19, 3-62, 4-21, 4-80 Subsea: 2-75, 3-21, 3-44, 4-18, 4-21, 4-47 Thermokarsting: 4-3, 4-13 Permanent Ice Pack (see Ice) 'Petroleum Product Spills: 2-28, 3-99, 4-44, 4-52, 4-54, 4-55, 4-72, 4-79, 4-81 Physiography: (see also Ice-Wedge Polygons, Thaw Lake, Permafrost) 3-16, 3-18 Phytoplankton: 2-41, 3-44, 3-50, 4-65, 4-67, 4-70, 4-80 Pipeline Construction Mode: 2-88, 4-27, 4-31 Pipeline Effects: (see Caribou, Dust, Drainage Patterns) Stream Crossings: 4-77 Pipeline Freeze Protection: 2-90 Pipeline Routing: 2-16, 2-43, 2-85, 2-86, 2-87, 2-95, 4-31, 4-34, 4-79, 4-80 Alternatives: 4-28 Plankton Impacts: 2-34, 2-66, 2-92, 4-2, 4-35, 4-55 Biocide: 4-69 Coagulant: 4-69 Mechanical: 4-70 · Polar Bear: 3-56, 3-57 Habitat: 3-30, 4-4, 4-7 Denning: 3-30, 4-7, 4-26 Po 1 ar Pack Ice: (see Ice) Polymer Flooding, Recovery: 2-11 'Pondin9 and Blockage: 3-32, 3-99, 4-3,_ 4.;4, 4-20, 4-24, 4-81 Population and Employment: (see also Manpower Requirements, North Slope, Statewide Impacts) 3-75, 4-91 Precipitation: (see Meteorology) Prehistory: 2-4, 3-2, 3-5 Preparers, List of: 6-1, 6-2 Prevention of Significant Deterioration (PSD): (see Air Quality) Primary Producers: (see Marine Biology, Vege- tation) · Primary Productivity: 3-21, 3-23, 3-31, 3-32, 3-50, 3-99, 4-24, 4-28 Produced Water: 2-20, 2-44, 2-50, 3-92 . Production, Comparison of Oil Quantities: 1-2 Production Centers: 2-18 Productivity, Biological: (see Biological Pro- ductivity) Productivity, Oil: 4-1 ,Project Abandonment: (see Abandonment, Project) Project Benefits: 4-1 Economic: 1-5, 4-1, 4-6 Oil Recovery: 1-2, 4-1, 4-6 Tax Revenue: 4-1 Project Description, Detailed: 2-20, Appendix. B Project Purpose and Need Effects on National Energy Production: 1-2 Effects on Production: 1-2, 1-4 Project Status: 1-1 Propeller Startup: 4-55 Prudhoe Bay: 2-13, 3-44 Facilities: (see Land Use) Oil Field: 3-15 Region: 2-1, 3-1 P~D Application: 3-66, 5-l, Appendix P Public Finance North Slope: 3-77, 4-92, 4-94 Statewide: 3-77, 3-80, 4-93, 4-94 Public Involvement: 7-1, Appendix A Purchases: 3-80, 4-92 Putul igayuk River: 3-6, 3-16, 3-57, 3-58, 3-61, 4-22, 4-27, 4-39 10-6 Recolonization: (see Biological. Recolonization) Rehabilitation Measures Gravel Berms: 4-20 Overburden: 4-18, 4-22, 4-55 Reservoir Engineering: Appendix K Reservoir Performance: (see Oil Reservoir Dynamics) Resource Commitments: 4-4 Biological Productivity: 4-3 Fuel Consumption: 4-4 Resource Use Planning: 3-86 Restoration: (see Gravel) Return Islands: (see Jones and Return Island Group) Road and Pad Construction: 2-43, 2-91, 4-2, 4-4, 4-18, 4-20, 4-23, 4-24, 4-27' 4-77 Sadlerochit Formation: 1-2, 2-1, 2-5, 2-11, 2-13, 2-20, 3-16, 3-90, 3-91, 4-3 Sagavanirktok River: 2-1, 2-13, 2-15, 2-26, 2-28, 2-36, 2-73, 2-77, 3-6, 3-17, 3-21, 3-26, 3-30, 3-39, 3-54, 3-56, 3-57. 3-58, 3-60, 3-61, 4-22, 4-27. 4-39, 4-56, 4-72, 4-77, 4-79 Sales Gas Conditioning Plant: (see Future Develop- ments) Salinity: (see Water Quality) Saltwater Spills: 2-43, 2-44, 2-46, 4-2, 4-28, 4-29, 4-43, 4-80, 4-81 Sand and Gravel: 3-17 Schedules and Construction Method: 2-54 Increment Phases: 2-54 Material Movement Schedule: 2-54 Module Installment: 2-54 Project Schedule: 2-55 Scoping Process: 1-1, 7-1 Sea Ice Level: (see Ice) Seawater Intake: (see also Fish Removal System, and Impingement, Entrainment and Entrap- ment} 2-17 Alternative Design: 2-24, 2-95, 4-76 Configurations, Comparison of-Alternatives: 2-66 Description: 2-28, 2-30, 2-66, 2-67 Impacts: 2-34, 2-36, 2-71, 2-77, 3-51, 4-4, 4-66 Recapture: 2-84, 4-75 Screen Designs: 2-69, 2-77, 4-76 Seawater Treating Plant: 2-15, 2-77, 4-13 Alternative: 2-78, 2-90, 2-95 Description: 2-28, 2-62, 2-67, 2-78, 4-42 Environmental Impacts: 2-34, 2-51, 4-90 Location: 2-83 Seawater, Recapture of Treated: (see Seawater Intake) Seawater Discharge, Treated: 4-52 Seawater Source Locations: 2-14 Seawater Spills: (see Saltwater Spills) Seals: (see Marine Mammals} Sedimentation Rates: 3-14 Sediments: (see also Water Quality) Accumulation: 4-44, 4-64 Descriptions: 3-39 Distribution: 3-33 Sources: 3-39 Suspended and Resuspended: 3-35, 3-39, 4-35 Transport: 3-14, 3-33, 3-39 Seismology Activities: 4-22 Ground f4otion Parameters: 3-15 Shorebirds: (see Birds) Shorefast Ice: (see Ice) Settling Ponds: 2-81 ! 1: Shoreline Configuration: 2-26, 4-2 Significant Conditions and Processes: 2-4 Simpson Lagoon: 2-14, 2-26, 2-27, 2-67, 2-71, 2-96, 3-26, 3t-34, 3-39, 3-40, 3-43, 3-52, 3-54, 3-56, 4-2, 4-14, 4-15, 4-36, 4-40, 4-41, 4-59, 4-60, 4-61 Socio-Economic and Cultural Features: (see also North Slope Social Features, Subsistence and Inupiat Eskimo) Construction Impacts: 4-91 Cumulative Impacts: 4-95 Historic: 3-4 Operation Impacts: 4-94 Sohio Alaska Petroleum Company: 1-1, 2-88, 3-6, 4-79 Soils: (see Permafrost) Tundra Soils: 3-19 Solid Waste: 2-52, 4-79 Solids Accumulation: (see also Water Quality) 2-38, 2-82, 4-47 Solids Composition: 4-47 Solids, Suspended: (see Water Quality) Sound Construction: 4-26, 4-55, 4-86 Impacts: 2-38, 3-99, 4-26, 4-30, 4-33, 4-55, 4-75, 4-90, 4-91 Levels: 3-76, 4-87, 4-88, 4-89 Operation: 4-87 Sensitivity: 4-55 Sources: 2-44, 3-68, 3-71, 3-73, 4-86, 4-88, 4-90 Species Diversity: 2-27, 3-20, 3-22, 3-25, 4-64 Species Vulnerability: 4-66 Spills: (see Petroleum Product Spills and Salt- water Spills) Spit Formation: 3-15, 3-36 State Lands: 4-13 State Oil Leases: 3-75 State Public Revenue: 4-1 Incremental Production Revenue: 4-94 Property Tax Revenue: 4-93, 4-95 Statewide Impacts Economy: 3-82, 3-83, 4-93 Employment: 4-91, 4-94 Permanent Fund: 3-84 Petroleum Revenues: 3-84, 3-85, 4-94 Population: 3-82, 3-83, 4-91 Steam Injection, Recovery: 2-13 Storm Surges and Tides: 3-34, 3-36, 4-56 Under-ice Currents: 3-36 Stump Island: 2-26, 2-66, 2-77, 2-84, 2-92, 3-21, 3-34, 3-37, 3-38, 3-52, 4-2, 4-39, 4-40, 4-44, 4-61, 4-62 Subsidence, Regional: 3-15 Subsidence from Oil Withdrawal: 4-21 Subsistence Contemporary Inupiat Culture: 2-28, 2-36, 2-73, 2-96, 3-2, 3-4, 3-51, 3-55, 3-56, 3-72, 3-99 Traditional Inupiat Culture: 3-4, 3-6, 3-33, 3-73, 3-100, 4-13, 4-93 Subsistence Resources: 4-5, 4-13 Suspended Solids: (see Water Quality) System Freeze Protection · Description: 2-50 Environmental Impacts: 2-51 Tax Revenue: (see North Slope Borough and State Public Revenue) Temperatures: (see Meteorology and Water Quality) Terrain Sensitivity: 4-28, Appendix L 10-7 Terrestrial Habitat: 2-88, 4-1, 4-23, 4-25, Appendix L Thal as pi arcticum: (see· Endangered or Threatened Spec1es) Thaw Lake: 3-16, 3-19, 3-21, 4-17, 4-20, 4-21, 4-81 Thermal Balance: 2-39 Thermal Discharge: 2-29, 2-34, 2-38, 2-51, 4-51, 4-53, 4-70 Thermokarsting: (see Permafrost) Threatened Species: (see Endangered or Threatened Species) Tides: 3-34, 3-36 Total Suspended Solids: (see Water Quality) Toxic Materials: 4-57 Toxicity Bioassays: 4-69, 5-3 Trace Metals: 3-39 Traffic Level: 2-43, 2-54, 4-2, 4-24, 4-30, 4-79 Transition Ice: (see Ice) Treated Seawater: 2-30, 2-29, 2-82 Treated Seawater Emergency Discharge: 2-51, 2-91 Tundra: (see Habitat) Tundra Islands: 3-14 Tundra Soils: 3-19, 4-2, 4-3, 4-4 Turbidity: (see Water Quality) Turbidity Plumes: 4-55 Turbulence, Diffuser Outflow: 4-51 Under-ice Currents: 3-34, 3-36, 4-36, 4-44 Dilution Factor: 2-38 Discharge: 2-38, 2-51, 2-82 Uniform Building Code: 3-15 U.S. Energy Balance: Appendix M U.S. Fish and Wildlife Service (USFWS): 1-1, 2-4~ 3-31 Vegetation, Description: 3-20, Appendix L Vegetation and Terrestrial Wildlife Alternatives: 4-27, 4-31 Construction Impacts: 4-22, 4-23 Operation Impacts: 4-28 Vegetation Habitats: (see Habitats) Vegetation Map ping/Habitat Evaluation: 3-22, Appendix L Vegetation Resource Value and Sensitivity: 3-22, Appendix L Wading Birds: (see Birds) Wastes: (see Domestic Waste, Liquid Wastes and Solid Wastes) Water Availability: 3-58, 3-61 Free Water: 3-58 Water Reservoirs: 2-94, 3-58 Water Use: 3-62 Water Circulation and Salinity: (see Currents/ Circulation and Water Quality) Waterfowl: (see Birds) Water Quality: (see also Sediments) 2-69, 3-39, 3-63, 4-3, 4-44, 4-56, 5-1 Bi ochemica 1 Oxygen Demand: 2-35, 4-48, 4-52 Chemical Oxygen Demand: 4-48 Dilution Factor: 4-46, 4-49, 4-52 Dissolved Oxygen: 2-35, 2-51, 3-39, 3-56, 3-57, 4-36, 4-39, 4-48, 4-52, 4-53 Dissolved Solids: 3-56, 3-57, 3-61 Impacts on: 3-100, 4-2 Mixing: 3~41, 4-2, 4-39 Nutrients: 3-20, 3-44, 4-36, 4-39, 4-45, 4-57, 4-78 pH: 4-45 Salinity: 2-26, 3-41, 3-42, 3-43, 4-36, 4-38, 4-39, 4-44, 4-45, 4-59 Temperature: 3-41, 4'-39, 4-45, 4-59, 4-78 Total Suspended Solids: 2-24, 2-35, 2-37, 2-38, 2-41, 2-69, 2'-82, 3-41, 4-46, 4-51, 4-52, 4-53, 4-54, 4-71, 4-77 Turbidity: 2-41, 2-84, 2-92, 3-44, 4-35, 4-39, 4-44, 4-52, 4-54, 4-59, 4-63, 4-75 Water Clarity: 3-44 Water Requirements: 4-78, 4-79 Water Use Permits, A 1 ask a Department of Natura 1 Resources: 3-58 Waterflood Configurations: 2-15, 2-16, 2-17 Technique: 2-14, 2-19 : Water Sources: 2-14 · Wave and Current Regimes: 2-26, 3-33, 3-34, 3-35 Wave Climate: (see a 1 so ·Sediments) Barrier Island Migration: 3-34 Coastline and Causeway :Erosion: 3-34 Permanent Ice Pack: 3-34 Wave Heights: 3-34 Wave Refraction and Sedfment Transport Analysis: 4-40 Wave Stresses: 4-57 West Dock: 3-40, 3-53 Wetlands Aesthetic Aspects: 3-33 Construction and Opera1:!ion Impacts: 3-98, 3-99, 4-31 . Food Chain Production: 3-31 Habitat: 2-43, 2-46, 2-47, 2-56, 2-88, 3-1, 3-24, 3-28, 4-24, 4-26, 4-34, Appendix L Nutrient and Energy Flow: 3-20, 4-25, 4-26 Use of: 3-33, 4-10 Value: 3-31, Appendix L Wilderness Value: (see Habitat Value, Environ- mental Profiles) Wildlife: 3-22, 4-3 Migration: 2-4, 3-2, 3-22, 3-24 Wind: 2-26, 2-71, 2-74, 2-84, 3-34, 3-66, 3-67, 3-68, 3-69, 3-70, 4-36, 4-40, 4-59 Zooplankton: 3-28, 3-50, 4-65,. 4-67 10-8