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Home My WebLink AboutBethel Area Power Plan Feasibility Assessment; Appendix D; Hydropower Resources 1984m O13 Alaska Power Authority BETH “4 LIBRARY COPY App. D Bethe | APPENDIX D Hydropower Resources : aie See + oa, Bethel Area Power Plan Feasibility Assessment APPENDIX D HYDROPOWER RESOURCES DRAFT Prepared for the Alaska Power Authority by Harza Engineering Company Draft April 1984 Chapter 7 II III TABLE OF CONTENTS INTRODUCTION Contents of the Report Objectives and Scope of Study Background and Previous Studies Acknowledgements ALTERNATIVE PROJECTS FOR HYDROELECTRIC GENERATION Introduction Identification of Potential Hydroelectric Sites Review of Previous Studies Map Studies First Screening Second Screening Third Screening Conceptual Project Layouts Comparative Analyses Site Selection THE CHIKUMINUK LAKE ALTERNATIVE Location and Access Project Setting Alternative Plans of Development General Description Project Arrangement . Project Functional Design ‘Hydrologic Aspects Geology of Foundations and Construction Materials Power and Energy Potential Basic Assumptions Input Data Page HHH H tot WORE II-1 II-1 II-1 II-1 II-2 II-3 II-5 II-7 II-8 II-9 II-12 IITI-1 III-1 III-1 III-2 III=-3 III-3 III-4 III-5 IITI-6 III=-6 III-6 IIiI-7 Chapter IV TABLE OF CONTENTS (cont'd) Description of Project Facilities Reservoir Dam and Spillway Intake Water Conductor Surge Control Facilities Powerstation Access Switchyard and Transmission Line Implementation and Construction Schedule Project Costs Construction Cost Operation and Maintenance Costs Alternative Project POTENTIAL ENVIRONMENTAL IMPACTS Summary Chikuminuk Lake Terrestrial Impacts Aquatic Impacts Allen River Water Quality Downstream Flow Variation Downstream Temperatures Fish Passage Transmission Lines Impact on Birds Visual Impacts Other Impacts Land Use Conflicts Wood-Tikchik State Park Refuge Lands : Native Lands Potential for Avoidance, Mitigation and Enhancement Unavoidable Impacts Mitigation Enhancement Proposed Environmental Studies and Monitoring Programs REFERENCES EXHIBITS -~ii- APPENDIX D-1 APPENDIX D-2 APPENDIX D-3 b TABLE OF CONTENTS (cont'd) Hydrology Investigations Geology of Hydroelectric Sites Environmental Resources -iii- \ LIST OF TABLES | Table No. Title II-1l Preliminary Project. Sizing II-2 PMF and Diversion Flood Estimates II-3 Bethel Region Monthly Peak Demand and Energy Generation (Year 2002) t III-1 Average Monthly Streamflows, Allen River III-2: Chikuminuk Lake, Energy Generating _ Capability III-3 Estimated Construction Cost of the Chikuminuk Lake Project III-4 Estimated Construction Cost of the . Chikuminuk Lake Alternative Project -iv- Page II-4 II~-6 II-10 III-5 III-7 III-15 III-17 Exhibit No. 1 2 10 li 12 13 14 15 16 17 18 19 LIST OF EXHIBITS Title Location Map, Potential Hydroelectric Sites Installed Capacity Versus Construction Cost Third Site Screening, Project Data Conceptual Project Plan, Chikuminuk Lake Conceptual Project Plan, Kisaralik River Lower Falls Conceptual Project Plan, Kisaralik River Golden Gate Falls Conceptual Project Plan, Kisaralik River Upper Falls Conceptual Project Plan, Kipchuk River Conceptual Project Plan, Upnuk Lake Chikuminuk Lake, Energy Generation Versus Construction Cost and Reservoir Elevation Kisaralik River Lower Falls, Energy Generation Versus Construction Cost and Reservoir Elevation Kisaralik River Golden Gate Falls, Energy Generation Versus Construction Cost and Reservoir Elevation Kisaralik River Upper Falls, Energy Generation Versus Construction Cost and Reservoir Elevation Kipchuk River, Energy Generation Versus Construction Cost and Reservoir Elevation Upnuk Lake, Energy Generation Versus Construction Cost and Reservoir Elevation Annual Economic Cost of Average Energy Annual Economic Cost of Firm Energy Relative Resource Values and Costs of Mitigation Location Map, Chikuminuk Lake Hydroelectric Project Exhibit No. 20 21 22 23 24 25 26 27 28 29 30 31 32 LIST OF EXHIBITS (cont'd) Title Conceptual Project Plan, Chikuminuk Lake Significant Data, Chikuminuk Lake Hydroelectric Project Reservoir Area ~ Volume Curve, Chikuminuk Lake Chikuminuk Lake Hydroelectric Project, 9,500 kW Development, General Plan and Sections Chikuminuk Lake Hydroelectric Project, General Profile and Sections Monthly Sequences of Flow, Allen River at Chikuminuk Lake Outlet Proposed Transmission Line Route Chikuminuk Lake Project Implementation Schedule Detailed Construction Cost Estimate, Chikuminuk Lake Hydroelectric Project Significant Data, Chikuminuk Lake Hydroelectric Project, Space Heat Alternative Chikuminuk Lake Hydroelectric Project - 24,000 kw Development, General Plan and Sections General Profile and Sections, Space Heat Alternative, Chikuminuk Lake Hydroelectric Project Factors Which May Influence Avian Collision Rates with Overhead Wires -vi- Chapter I INTRODUCTION Contents of This Report This Appendix presents results of the studies undertaken to select the preferred hydroelectric project for use in formu- lating alternative energy supply plans for the Bethel area. Non-hydro energy projects are addressed in Appendix C. The formulation of energy supply plans, considering hydro and non- hydro components, is presented in Appendix E. Appendix C is divided into four chapters. Chapter I contains background information and a description of the objective and scope of these studies. Chapter II presents the screening studies under- taken to select the most preferred project, which is described in detail in Chapter III. Chapter IV contains a discussion of the potential environmental impacts of the selected project. Detailed information is contained in three supporting Appen- dices: ° Appendix D-1l: Hydrology Investigations ° Appendix D=2: Geology of Hydroelectric Sites ° Appendix D-3: Environmental Resources Objectives and Scope of Study The objectives of the study were to select a hydroelectric project and develop a project plan conceptually designed and suited to the environment, market area energy needs, and local engineering aspects, at a level of confidence equal to the other alternative energy supply plans being considered for the Bethel Area Power Plan Feasibility Assessment. The scope of this study included the following items: 1. Perform data collection and analyses required to develop conceptual designs, determine plant costs, and identify any major environmental obstacles. 2. Determine the plan of development for the selected hydroelectric project. 3. Determine with reasonable certainty the cost of the project. I-1 —! 4. Determine the environmental impacts of the project along with mitigating measures that could be taken to offset adverse impact. Background and Previous Studies There have been numerous water and hydroelectric resources investigations in Alaska since World War II. The Bureau of Reclamation conducted the first state-wide reconnaissance of potential hydroelectric sites in 1948. A separate series of regional water resources investigations was made by the U.S. Army Corps of Engineers in the late 1950's. From 1962 to 1967, the Bureau of Reclamation prepared a comprehensive inventory of state-wide hydroelectric resources which subsequently has been updated by the Alaska Power Administration (APA). Since 1975, reports concerning the Bethel region have uti- lized previous inventories to further evaluate the hydroelectric potential. The hydropower resources study utilized these previ- ous inventories and investigations to identify potential hydro- electric sites within the region. Studies performed by others were reviewed to ascertain all available information on possible hydroelectric sites in the’ Bethel region. The review formed a basis for the studies. The following studies were reviewed: 1. A Regional Electric Power System for the Lower Kuskok=- wim Vicinity, A Preliminary Feasibility Assessment prepared for the United States Department of the Interior, by Robert W. Retherford Associates, July 1975. 2. Small Hydroelectric Inventory of Villages served by Alaska Village Electric Cooperative, United States . Department of: Energy, Alaska» Power Administration, December 1979. 3. Small-scale Hydropower Reconnaissance Study, Southwest Alaska, Department of the Army, Alaska District, Corps of Engineers, Anchorage, Alaska, R.W. Beck and Associ- ates, April 1981. 4. Reconnaissance Study of the Kisaralik River Hydroelec- tric Power Potential and Alternate Electric Energy Resources in the Bethel Area, prepared for the Alaska Power Authority, by Robert W. Retherford Associates, March 1980. I-2 Application for Preliminary Permit, Kisaralik Hydro- electric Project, prepared for the Alaska Power Authority, by Robert W. Retherford Associates, April 1980, Bristol Bay Regional Power Plan, Netailed Feasibility Analysis, Interim Feasibility Assessment, Stone and Webster Engineering Corporation, July 1982. Acknowledgements We acknowledge and appreciate the valuable assistance and advice offered by staffs of the following organizations: Alaska Power Authority Harding Lawson Associates Arctic Environmental Information and and Data Center I-3 Chapter II ALTERNATIVE PROJECTS FOR HYDROELECTRIC GENERATION Introduction Three successive screenings were conducted to select the preferred hydroelectric project. The first screening was performed on the basis of available maps and published information. Two sites were identified from previous studies and ten sites were located on U.S. Geological Survey (USGS) topographic maps. Seven sites were retained on the basis of broad engineering criteria. _The second screening involved the evaluation of the seven sites on the basis of estimated construction cost. These costs were developed from parametric cost curves. In the third or final screening, conceptual project plans were made for each of the sites and they were evaluated based on environmental, geologic and cost information. Cost estimates were based on quantity takeoffs. The preferred site was select- ed as having lower construction and economic costs and fewer environmental constraints to project development. The screening studies were made to identify the preferred hydroelectric project which could meet the future electrical energy needs of the Bethel region. Initially, it was assumed that space heating needs would be met by other, non-electrical means. After identification of the preferred site, an alterna- tive layout was evaluated, which included provisions for meeting a portion of the space heating demand. Identification of Potential Hydroelectric Sites A review of previous studies was conducted to identify potential hydroelectric sites. In addition, map studies were conducted to locate potential sites within the Kilbuck, Kuskowim and Wood River Mountains. . Review of Previous Studies Several studies, of varying levels of detail, have been performed to identify hydroelectric potential in and near the Bethel study area. TI-1 The 1975 Alaska Power Administration report includes recom-— mendations to proceed with studies for potential small-hydro sites near the villages surrounding Bethel and to consider studies for the development of the Kisaralik River (Lower Falls) Hydroelectric Project. Two small-hydro studies were initiated and completed during 1976-1981. The 1979 APA/AVEC studies did not identify any hydroelectric projects near the villages within the study region. The 1981 Corps of Engineers small-hydro inventory of south- western Alaska identified 14 sites near communities that met the criteria established for the study; however, none of the poten- tial hydroelectric projects were located in the Yukon-Kuskokwim Delta area. These studies concluded that feasible development of small-hydro in the delta area is severely limited because of the gentle gradients of the streams. Hence, future studies focused on development of hydroelectric power projects that were capable of meeting the power and energy requirements on a regional rather than local level. The 1980 reconnaissance level studies on the Kisaralik River (Lower Falls) Hydroelectric Project identified a develop- ment consisting of a 300-foot high rockfill dam near Lower Falls on the Kisaralik River and an underground powerstation with two- 15 MW units. The estimated average annual energy generation is 186,900 MWh. In April 1980 an application for a FERC prelimi- nary permit for this project was submitted. The July 1982 report on the Bristol Bay regional power studies identified the Chikuminuk Lake Hydroelectric Project. This development would comprise a 100-foot high rockfill dam on the Allen River downstream from Chikuminuk Lake and a powersta- tion with two-8 MW units. The estimated average annual energy generation is 76,100 MWh. The review of the previous studies yielded valuable back- ground information and identified the Kisaralik and Chikuminuk Lake hydroelectric sites. The current studies included an inde- pendent assessment of the Bethel region to identify additional hydroelectric sites based on USGS map studies. Map Studies The map studies encompassed an area located within the Kilbuck, Kuskokwim and Wood River Mountains. The boundaries of the study area were approximately Township 11 North through Township 4 South and Range 55 through 66 West of the Seward Meridian. The sites were identified and investigated using USGS II-2 quadrangle maps of the 1:250,000 and 1:63,360 series. The fol- lowing broad engineering criteria were used as a guide for site identification. 1. Sufficient topographic relief to develop a ininimum head of 50 feet. 2. Drainage area adequate to yield water supply for the range of installations considered. Ten sites were identified in the map studies. These sites and the two sites previously identified are shown on Exhibit l. First Screening The twelve sites were compared on the basis of the follow- ing items: 1. Average annual streamflow available for hydroelectric generation 2. Head available to develop power 3. Size of dams and dikes 4. Reservoir storage volume Average annual streamflow was estimated by transposing average annual streamflow of the Nuyakuk River near Dillingham gage to each site using a transposition ratio which related drainage area and average annual precipitation. This procedure is discussed in Appendix D-l. Table II-l shows the drainage area and average annual streamflow at each site. The Energy Use and Demand studies indicated that the pro- jected power requirements for the study area will range between 7 and 15 MW. For the first screening the sites were initially sized for 10 MW using the basic equation for hydroelectric power. kW = —H0§ gross head in feet design flow in cfs efficiency (assumed to be 0.82) where H Q e oni The design flow was estimated by multiplying 1.5 times the average annual streamflow. The multiplier was based on the fact that, in five months of the year, average monthly runoff is II-3 Table II-1 PRELIMINARY PROJECT SIZING Average Normal Annual Reservoir Drainage Stream- Gross Eleva- Dam Project Name Area flow Head tion Volume , (sq mi) (cfs) (feet) (feet) (1000 cy Chikuminuk Lake 348 1,550 62 598 400 Kisaralik River (Lower Falls) 500 1,945 49 849 300 Kisaralik River L (Golden Gate Falls) 550 2,105 46 756 230 Kisaralik River (Upper Falls) 271 1,120 86 1,041 450 Kipchuk River 224 935. 103 1,058 650} Upnuk Lake 105 470 204 802 100 Milk Creek _ : (Upper Site) 100 440 218 1,168 2,200 Milk Creek : (Lower Site) 113 495 194 964 1,600 Salmon River 230 , 770 125 975 3,800. Tulksak River 144 440 218 738 16,600 - Izavicknik River 231 1,035 93 383 8,500°: Fog River 7 92 250 384 "984 21,200 equal to or greater than the average annual flow. The gross head was computed and the normal reservoir elevation and corres- c ponding dam heights were estimated from the quadrangle maps. : Table II-l summarizes the project sizing at each site. At each site a cross section at the chosen dam axis was developed and the volume of rockfill material was computed for a range of dam heights. In addition, reservoir area-volume curves were developed for each site. These relationships were utilized II-4 to’ identify the sites where topographic factors were favorable regarding construction costs and flow regulation. The unit price for dam rockfill material was estimated at $25 per cubic yard. Hence, the construction cost of the dams was a major cost component of the total construction cost and judged to be a good indicator of site viability. Table II-1 shows a comparison of dam volumes required to develop 10 MW at each of the sites. The Salmon River, Tuluksak River, Izavicnick River and Fog River sites were rejected based on a comparison of the dam height versus fill volume relationship. The Milk Creek upper site was retained in favor of the lower site because the reser- voir storage volume at the lower site was 65 percent less than the storage volume at the upper site. The seven sites retained for further study were Chikuminuk Lake, the three Kisaralik River sites, Kipchuk River, Upnuk Lake and the Milk Creek upper site. Second Screening For each of the seven remaining sites additional hydrologic investigations were performed and USGS topographic maps were reviewed for desirable locations of a) dams and dikes for reser- voirs, b) spillways, c) powérstations, and d) water conductors. Physical characteristics and construction cost estimates for the potential projects were developed. Average annual streamflow estimated by transposing average annual streamflow of the Nuyakuk River near Dillingham gage are presented in Table II-l. The preliminary estimate of the PMF for each site was based on Creager's formula. The diversion flood estimates were based on multiple-regression analyses. Table II-2 shows the PMF and diversion flood values computed for the seven sites. The PMF and diversion flood studies are discussed in more detail in Appendix D-1l. The physical characteristics of each potential project were developed using USGS quadrangle maps (1:63,360 series) and cross sections at the damsites. At each site three dam heights rang- TI-5 Table II-2 PMF AND DIVERSION FLOOD ESTIMATES Diversion PMF Peak Peak Site Flow Flow (cfs) : (cfs) Chikuminuk Lake 287,000 11,800 Kisaralik River (Lower Falls) 341,000 19,500 Kisaralik River (Golden Gate Falls) 356,000 21,000 Kisaralik River (Upper Falls) 254,000 11,600 Kipchuk River 230,000 8,800 Upnuk Lake 154,000 3,500 Milk Creek (Upper Site) 150,000 6,000 ing from 30 feet to 300 feet were investigated and approximate powerstation elevations were established. Plant discharge and installed capacity were computed using maximum gross head, average annual streamflow, and a plant efficiency of 82 percent. Water conductor diameters were determined by maintaining hydrau- lic head losses in the range of five percent of the gross head. The spillways were sized to pass the PMF peak flows discussed previously. Transmission line routes were sketched on USGS maps and line lengths and costs were estimated. All line voltages were assumed to be 138 kV. The construction costs were estimated using parametric cost curves for the major structures (i.e. dams, powerstations, water conductors, and spillways). Diversion costs were assumed to be 12 percent of the sum of dam and spillway costs for the various sites. Cost for miscellaneous items such as intakes, surge tanks, access, reservoir clearing, and control structures were included as being 15 percent of the sum of dam, spillway, water conductor, power plant, and diversion costs. The parametric cost data utilized reflects cost experience in Alaska, remoteness of the sites, and considerations related to weather and access. Parametric cost evaluation methods ex- clude major cost items associated with geology. The construc- II-6 tion costs, at the December 1982 price level, provide for civil, electrical, and mechanical facilities and include a 40 percent contingency for errors and omissions and for engineering and owner's administration. The costs do not include allowances for interest during construction and escalation. The construction costs for a range of installed capacity at each site aré ‘pre- sented graphically on Exhibit 2. A review of Exhibit 2 indicates that the Chikuminuk Lake and Upnuk Lake sites are the most favorable from a construction cost standpoint. The costs of the Kipchuk site, the three Kisaralik sites, and Milk Creek site are generally similar throughout the range of installed capacities considered, with the exception of the Milk Creek site when it is developed beyond an installed capaci- ty of about 12 MW. Based on the results of the second screening it was con- cluded that a definitive ranking of the sites from most to least favorable could not be made-without further environmental, geo- logic and engineering investigations. Third Screening The sites retained were reconnoitered in the field by a hydroelectric engineer, geologist and environmental scientist. As a result of the field reconnaissance, the Milk Creek site was eliminated due to extensive faulting in the reservoir area. The remaining six sites are listed below: ° Chikuminuk Lake ° Lower Falls, Kisaralik River ° Golden Gate Falls, Kisaralik River ° Upper Falls, Kisaralik River ° Kipchuk River ° Upnuk Lake Conceptual project layouts were made for each of the remaining six sites based on required hydroelectric facilities, geologic features and geotechnical considerations. For each site average monthly streamflows were developed by transposition of Nuyakuk River monthly streamflow data. Computer studies were performed using Bethel's peak demand and energy requirements to II-7 determine generating capabilities for selected reservoir levels for each site. Cost estimates were prepared using estimated quantities and unit prices based on preliminary labor, material, and construc- tion equipment costs. The results of the cost estimates and generating capability studies were utilized to develop construc- tion cost versus energy generation and reservoir elevation curves. The details of the third screening are discussed in the following sections. The site geology descriptions for the seven sites are included in Appendix D-2. The environmental aspects of the sites are included in Appendix D=-3. Conceptual Project Layouts The conceptual project layouts for the six remaining sites were developed by the following methods. 1) The location, height and length of the dams were reviewed and refined, if necessary, based on the field reconnaissance. 2) Diversion schemes were developed and tunnels were sized to discharge the peak inflows discussed previ- ously. _ 3) A range of maximum reservoir elevations were selected from the area-volume curves and corresponding dam volumes were computed. 4) Plant generating capacity was based on the capability to supply dependable capacity of nine megawatts at the minimum head. Plant efficiency was based on typical performance curves for horizontal Francis units. 5) The diameter of the water conductor was based on plant discharge and the maintenance of tunnel hydraulic losses in the range of 3 percent of the gross head. 6) The probable maximum flood (PMF) was estimated for each site as described previously. Using the ratio of reservoir area to drainage area, and engineering judgement, the spillway design floods were computed as a percentage of the PMF and the spillways were sized accordingly. 7) Airstrips and access roads were located on USGS maps. Airstrips were assumed to be 5,000 feet in length. II-8 The access road length from the airstrip to the plant site was determined from the maps. Minimum thickness for airstrips and roads was assumed to be four feet. 8) Transmission line routes were sketched on USGS maps to determine transmission line lengths. Transmission line voltage was assumed to be 138 kV. Exhibit 3 presents basic project data and major dimensions for each of the six sites. A conceptual layout of each site is presented on Exhibits 4 to 9. Comparative Analyses The selection of the most favorable site for the develop- ment of a hydroelectric project was based on the following con- siderations; (1) generating capability, (2) construction cost, and (3) environmental aspects. Power and Energy Operation Studies. Preliminary reservoir operation studies were performed to determine the generating capability of each of the alternative projects. For each alter- native the computer simulations utilized synthesized monthly streamflow, reservoir area-volume curves, assumed plant perform- ance curves, and forecasted monthly electric load demands. The synthesized monthly streamflow was estimated by trans- posing monthly Nuyakuk River streamflow data to each site using the transposition ratio discussed previously. The monthly electric peak and energy demands were based on the 2002 most likely demand for the total Bethel region. A distribution loss of 8 percent was added to the energy demand to compute energy generation. The results are presented in Table II-3. The energy generation required to meet Bethel's most likely demand in the year 2002 is 39,000 MWh. For each. of the alternatives, firm and average monthly energy production, for a range of reservoir elevations and a dependable capacity of nine megawatts, were estimated using the reservoir operation computer program. Plant capability beyond nine megawatts was not considered. Construction Cost Estimates. The conceptual layouts were used as a basis for preliminary quantity take-offs. Cost esti- mates for the range of reservoir elevations determined in the II-9 operation studies were prepared using estimated quantities and preliminary unit prices based on labor, materials and construc- tion equipment costs. The costs, at the December 1982 price level, include civil, electrical, and mechanical facilities and a 40 percent allowance for errors and omissions and for engineering and owner's administration. Table II-3 BETHEL REGION MONTHLY PEAK DEMAND AND ENERGY, GENERATION (Year 2002) Month Peak Demand Monthly Energy (kW) (MWh ) January. 8,360 3,940 February 7,920 3,550 March 7,480 3,314 April 6,600 2,964 May 6,160 2,925 June 6,160 2,808 July 6,160 . 2,925 August 6,600 3,040 September 6,600 2,964 October --7,040 3,315 November 7,920 3,315 December 8,800 3,940 Annual 8,800 39,000 The construction cost estimates, in conjunction with the firm and average energy generation estimates, were used to develop reservoir elevation versus construction cost and energy generation curves. Exhibits 10 through 15 present these rela- tionships for the six alternative sites. , Economic Cost of Energy. The economic costs were calcu- lated utilizing estimated annual costs and the average and firm energy estimates. The annual costs of developing and maintaining the projects were based on the annualized capital costs and annual operating costs. Annualized capital costs were computed based on a 3.5 percent discount rate over a 50 year life of the project. II-10 Operation and maintenance costs were estimated as a function of total capital cost. The total annual cost is the sum of the annualized capital cost and annual operation and maintenance costs. The economic cost of average and firm energy was computed by dividing the total annual cost by the estimating average and firm energy. The estimated annual economic cost of the average and firm energy for the sites are shown graphically on Exhibits. 16 and 17. Exhibit 16 indicates that, as the average annual energy generation from the projects approaches the 2002 most likely energy demand of 39,000 MWh, the Kisaralik River Upper Falls, Golden Gate Falls, and Upnuk Lake economic cost curves exhibit large incremental increases in economic cost for small increments in average annual generation. The trend is primarily due to the increased costs of providing required reservoir storage for energy generation. The Upnuk Lake site generating capability is limited by instream flow constraints and topographic factors. The Chikuminuk Lake, Kisaralik River Lower Falls, and Kipchuk River economic cost curves trend downward. The firm energy generation comparison, Exhibit 17, indi- cates that the Kisaralik River Upper Falls, Golden Gate Falls, and Kipchuk River economic cost curves trend upward as the firm energy generation. from the projects approaches the 2002 most likely energy demand. The firm energy generating capability of the Upnuk Lake site exhibits a very high economic cost in com- parison to the above sites because of the limitations discussed previously. The Chikuminuk Lake and Kisaralik River Lower Falls economic cost curves exhibit decreasing economic costs for incremental increases in firm energy generation. The comparison indicates that the Chikuminuk Lake project is the most favorable from -an economic cost of energy standpoint for both average and firm energy generation. This is primarily due to the large storage available for small incremental costs. In addition, for both Chikuminuk Lake and Kisaralik Lower Falls, the relationships’ indicate that developments with even greater energy storage capability appear economically attractive. Environmental Comparison. The environmental comparison is based on site-specific characterizations of the resources at each site. The resources selected for study at the sites were assigned a relative value. The relative resource values are as follows: It-11 Relative Value of 1 - low sensitivity Relative Value of 2 - moderate sensitivity Relative Value of 3 - high sensitivity The selected species, species groups and resources assigned values are those of national or state importance and which would likely necessitate. measures to mitigate adverse impacts attributed to the project. The resource values are tabulated on Exhibit 18. Development of any one of the sites would have little effect on terrestrial forms. Project areas are covered by an ericaceous heath, which is prevalent throughout thousands of square miles of the Kuskokwim and Kilbuck Mountains and adjacent areas. Further, the sites are not located in important seasonal ranges or major migration routes. Consequently, loss of habi- tats due to project structures, support facilities and reservoir impoundments would have little direct effect on terrestrial forms. Several of the study sites have high-value commercial and sport fisheries. Upnuk Lake and Kipchuk River have the highest values, followed closely by the Kisaralik River sites. Develop-— ment of any of these sites would likely require a costly mitiga- tion program. Comparison of the sites indicates that the Milk Creek and Chikuminuk Lake sites would have the least environmental impact followed by the three Kisaralik River sites. The Kipchuk River and Upnuk Lake sites would have the most environmental impact. Site Selection Based on the results of the field reconnaissance and engi- neering studies, the conceptual designs of the alternative proj- ects were refined. .Construction costs were developed and gen- eration capability was determined. An overview. and .site-spe- cific characterization of the environmental resources at each potential hydroelectric site was conducted. These comparative analyses resulted in selection of the Chikuminuk Lake site for further study. II-12 Chapter III THE CHIKUMINUK LAKE ALTERNATIVE Location and Access The Chikuminuk Lake Hydroelectric Project is located in the SE 1/4 of Section 24, TIN, R55W of the Seward Meridian, as shown on Exhibit 19. The project would utilize the flow and head available on the Allen River near the outlet of Chikuminuk Lake. All of the proposed project structures and other required con- struction such as roads and an airstrip would be located within the Wood-Tikchik State Park. Chikuminuk Lake has elevation of 598 feet above mean sea level. At this elevation, the lake surface area is about 25,600 acres. Water discharges from the lake into the Allen River. The Allen River flows in a south-southeast direction about 11 miles and discharges into Lake Chauekuktuli. Several sets of rapids exist near the Chikuminuk Lake outlet, as the river level drops about 85 feet within a mile from the lake. Chikuminuk Lake is only accessible by helicopter, float plane and small boat from neighboring watersheds. Since the site is inaccessible by roads or navigable waters, project con- struction and operation would require the construction of an airfield to accommodate large payload airplanes. The airfield would be located adjacent to the hydroelectric facilities and would consist of a single 150-foot wide, 5,000-foot long run- way. Project Setting The Chikuminuk Lake area is characterized by steep moun- tains and wide valleys with rolling hills. Average maximum elevation of the east-northeast trending range is 5,000 feet. The soils are generally poorly drained and can be expected to be underlain with discontinuous masses of permafrost. A typical ericaceous heath dominates the vegetation of the area. The overstory is composed chiefly of dwarf blueberry supplemented with spirea and labrador tea. The understory is composed chiefly of crowberry, which in places is broken by reindeer moss and scattered low-bush cranberry and dwarf sedges. The project area provides refuge for beaver, moose, black bear, brown bear, otter, mink and ground squirrels, while wol- III-1 verine, fox, wolf and caribou are frequent visitors. Chikuminuk Lake is a typical northern oligotrophic lake. It has a rela- tively high average depth and a small proportion of shallow water area which is confined to a narrow shelf around the shore- line. The shoreline consists mostly of gravel and cobble that probably serve as spawning beds for lake trout, Arctic grayling, and Dolly Varden. The rapids in the Allen River near the Chikuminuk Lake outlet preclude migration of anadramous fish into the lake. However, salmon commonly spawn in the Allen River delta at Lake Chauekuktuli. Sockeye are the most abundant species, but pinks, kings, and probably coho also are present. The climate of the Chikuminuk Lake area can be classified as transitional between maritime and continental. The prevail- ing storm winds are from the southeast. The average annual pre- cipitation over the basin is about 40 inches and mean annual snowfall is about 80 inches. The mean annual temperature is about 29°F and the temperatures normally range from a low of -5°F in January to a high of 65°F in July. Alternative Plans of Development Two alternative dam sites were investigated for the Chikuminuk Lake project. The conceptual project plans are shown on Exhibits 4 and 20. For this study, site access, availability of construction materials, foundation conditions, and reservoir water-retaining capability were compared to select the preferred arrangement. The comparisons are described below. The bedrock conditions are nearly identical for both dam sites. They are located in tight, steep-walled gorges. From the standpoint of proximity to fill materials, the upstream site has an advantage as moraine deposits are only about 1,000 feet from the proposed dam location. , Foundation conditions beneath the spillway for a rockfill dam at the downstream site are questionable. Major questions relate to the nature of materials in the ridge beneath the spillway and, particularly, the depth to sound bedrock. Initial reconnaissance indicated slump deposits on both the upstream and downstream sides of this ridge. Field mapping was unable to locate evidence of bedrock in the northern half of the proposed spillway, while bedrock outcrops were noted in adjacent slopes. It is possible that former streamflow from the dry valley on the opposite side of the Allen River or the upper reaches of the Allen River, may have cut a valley through the ridge which was later filled with morainal or alluvial deposits. Another possi- bility is that weaker, relatively erodible rock underlies the TIII-2 area at shallow depth beneath a cover of glacial moraine. A preliminary seismic refraction profile, 240 feet long, was obtained beneath the spillway ridge. Seismic velocities obtain- ed from this survey are inconclusive, as they could represent compact saturated glacial fill or a weaker sedimentary rock. The spillway for a rockfill dam at the upstream site would be in an area of thin (10-20 feet) morainal cover overlying massive bedrock. The spillway would discharge to an adjacent tributary (dry valley), which, as an underfit stream, appears to have sufficient capacity to receive design flood spills and dampen the effect of surging into the Allen River. Alluvium in the dry valley would be subject to erosion. The general water~retaining capabilities of the reservoirs would be similar. However, the indicated unfavorable foundation conditions of the spillway ridge at.the downstream site would probably require grouting and/or a cutoff. Without treatment, seepage could occur through the zone of weak rock or glacial- alluvial deposits. Access to the upstream site diversion tunnel would be simple from the intermorainal area, while the downstream site diversion tunnel scheme would involve the construction of spur roadways to the portal area. From a diversion standpoint, the upstream site has the advantage of good access to the portal and proximity of abundant fill. material from the morainal deposits for a cofferdam. Both schemes involve excavations for the power tunnel and powerhouse in the left abutment. The power tunnel for the down- stream layout would be shorter, yet the longer tunnel for the upstream layout could be worked from two headings, which would affect the construction schedule. Tunneling conditions at both sites would be favorable. Rock cover for an underground power= house at both sites appears to be marginal. Considering site access, availability of construction materials, competency of the spillway foundation, and reservoir water-retaining capability, the upstream Chikuminuk site (Exhi- bit 20) was selected for further investigation. General Description Project Arrangement Pertinent project data is listed on Exhibit 21, and Exhibit 22 presents the Chikuminuk Lake area-volume curves. The general plan and profile and sections of project features are shown on Exhibits 23 and 24. III-3 The project would consist of the following principal ele- ments: . 1. A rolicrete gravity dam across the outlet of Chikuminuk Lake. : 2. An uncontrolled spillway in the center of the dam with a design discharge of 5,000 cfs. The normal maximum reservoir level, established by the spillway crest, would be El. 610. 3. A power intake structure with trashracks at each open- ing and bulkhead gates for closure, 4, A 14-foot diameter power tunnel, 2,580 feet long, connecting the intake to the powerhouse. Upstream of the powerhouse a wye branch will be provided to dis- tribute the flow to two generating units. A surge chamber will be located upstream from the powerhouse to limit pressure fluctuations in the power tunnel under transient flow conditions. 5. A powerhouse containing two horizontal Francis tur- bines, two 4.75 MW generators, and electrical switch- gear. The transformers and take-off structures would be located adjacent to the powerhouse. The switchyard would be located north of the powerstation. 6. Other project facilities include: a.) A permanent airstrip and access road. be.) A 138 kV transmission line, about 130 miles in length, from the project to Bethel. c.) A new substation in Bethel. Project Functional Design The Chikuminuk Lake hydroelectric project would regulate the outflow of Chikuminuk Lake for the production of power and energy. The project would have an installed capacity of 9.5 MW at a rated net head of 85 feet and a dependable capacity of 9 MW at a minimum net head of 80 feet. The project was sized to meet the monthly energy requirements through the year 2002 on a firm basis or produce 39 GWh annually, with secondary energy occurring in all months. The average annual energy production would be about 60 GWh. III-4 Hydrologic Aspects Hydrologic analyses were made to estimate the probable maximum flood (PMF) and the diversion flood. A 25 year return period was used for the diversion flood. The results are sum- marized below: 284,000 cfs . 233,320 acre-feet 119 ” 14,000 cfs PMF Peak Inflow PMF Volume Creager's "C" Diversion Flood The monthly streamflows for the Allen River for the period of record 1954 to 1981 were synthesized by regression tech- niques. Table III-l1 shows the average monthly streamflows for the period of record and Exhibit 25 contains the monthly syn- thetic sequences of Allen River flow. An analysis of sediment inflow was made and the sediment inflow was judged to have an insignificant impact on the project because of the large storage volume of Chikuminuk Lake. Details of the hydrology studies are presented in- Appendix D-1. Table III-1l AVERAGE MONTHLY STREAMFLOWS ALLEN RIVER Month Streamflow (cfs) January Lo 267 February 938 March 3,746 April 3,499 May 2,196 June 1,903 July 1,740 August 1,120 September 644 October 448 November 348 December 286 Mean Annual 1,432 III-5 Geology of Foundations and Construction Materials The Chikuminuk Lake site geology is described in Appendix D-2; a brief summary follows. Chikuminuk Lake occupies a glacially-enlarged valley sys- tem, bound on the southeast margin by a series of recessional moraines. The moraines have been eroded to bedrock level which forms at the outlet to the Allen River. The exposed bedrock rock units are very hard, siliceous carbonates, sandstones, shales and conglomeratic sandstones of the Cretaceous Gemuk group. Bed thickness ranges up to 10-15 feet, and the outcropping rock has a massive appearance. Thin- bedded (one-two inch thick) units, primarily in the shales, are exposed locally. The surface soils at the Chikuminuk site are glacial in origin and include ground moraines, lateral and recessional end moraines, and outwash (alluvial) deposits. The evaluation of regional seismicity involved a review of data maintained on computer file by NOAA (National Oceanographic and Atmospheric Administration). The largest nearby event was recorded at 5.1 Magnitude and occurred within 15 to 20 miles of the site. These data suggest that an earthquake acceleration value of 0.1g can be used for preliminary design purposes. Power and Energy Potential Reservoir operation studies were performed to determine the power and energy that could be produced by the Chikuminuk Lake project. The operation studies were performed for a range of reservoir levels utilizing the most likely monthly electric load demands for the Bethel region in the year 2002, presented in Table II-3. The peak power demand includes an allowance of 10 percent for station service losses, transmission losses, and other contingencies. The energy demand includes an 8 percent allowance for distribution losses. Basic Assumptions Basic assumptions employed in the operation studies are: 1. The reservoir is full at the start of the operation studies. 2. The maximum normal reservoir water surface is the elevation of the top of the spillway crest. III-6 3. Annual energy generation requirements are: based on the forecasted monthly demand. Input Data The input data for the operation studies are: 1. Area-volume curves (Exhibit 22). 2. Monthly streamflows for the period 1954-1981 (Exhibit 25). 3. A range of maximum reservoir operating levels between El. 598 and El. 620 with maximum drawdown to El. 598. 5. Monthly peak load and energy demand patterns. Based on these studies the Chikuminuk Lake hydroelectric project meets the Bethel region 2002 monthly energy demands on a firm basis when developed to a normal reservoir elevation of 610 feet above mean sea level. Monthly firm, secondary and average energy production for the project at El. 610 are shown on Table III-2. Secondary energy occurs in all months. Table III-2 CHIKUMINUK LAKE ENERGY GENERATING CAPABILITY Month Firm Energy Secondary Energy Average Energy (MWh ) (MWh ) (MWh ) Jan. 3,940 732 4,672 Feb. 3,550 467 4,017 Mar. 3,314 534 3,848 Apr. 2,964 203 3,167 May. 2,925 104 3,029 Jun. 2,808 2,199 5,007 Jul. 2,925 3,567 6,492 Aug. 3,040 3,543 6,583 Sept. 2,964 3,468 6,432 Oct. ~ 3,315 2,170 6,485 Nov. 3,315 2,033 5,348 Dec. 3,940 855 4,795 Totals 39,000 20,875 59,875 III-7 Description of Project Facilities Reservoir The reservoir created by the dam would raise the present normal elevation of Chikuminuk Lake 12 feet. The normal maximum reservoir level would be at El. 610. This elevation was derived from the power and energy -operation . studies. The minimum reservoir elevation would be El. 600. Reservoir operation between El. 610 and El. 600 would provide a usuable storge of 230,000 acre-feet for power generation. Exhibit 22 shows the reservoir area-volume curves. Chikuminuk Lake is located in a discontinuous permafrost zone. Therefore, the moraine formations may contain frozen zones. Changes in the natural lake level could alter the ther- mal regime of the moraine deposits and cause settlement or affect permeability. A preliminary seepage analysis of the left abutment was performed based on vertical and horizontal flow nets developed from observed bedrock elevations and an estimated permeability constant determined from a moraine soil sample. The results indicated that seepage losses could be on the order of 50 to 100 cfs over a reservoir elevation range of 620 to 660. Based on these results, a slurry wall cut-off was included in the conceptual designs for normal reservoir elevations greater than El. 620. Further investigation will be required to assess the pres- ence of permafrost and the water-retaining capability of the morainal ridges which form natural embankments across the end of Chikuminuk Lake. Dam and Spillway A rollcrete gravity dam containing an ungated overflow spillway would be constructed on the Allen River about 600 feet downstream from the outlet of Chikuminuk Lake as shown on Exhi- bit 23. The maximum structural height of the dam would be about 45 feet. The dam foundation would be excavated to sound rock. A grout curtain would be constructed under the dam to reduce seepage through the rock foundation. : The uncontrolled spillway would be located in the center portion of the dam and would have a crest elevation of 610 and crest length of 50 feet. Flood routing studies were performed using the PMF inflow hydrograph (see Appendix D-2). The peak spillway discharge is 5,000 cfs and the maximum surcharge ele- vation is 618. Allowing four feet of freeboard, the dam crest would be at El. 622. The selection of the type of dam was based on the availa- bility of construction materials, site geology, climatic condi- III-8 tions, and construction cost. The construction materials avail- able at the site include sand, gravel and aggregate from the moraine and downstream alluvium deposits. Random rockfill and rip rap could be obtained from required spillway excavation. Thin clay beds occur but significant deposits are’ not apparent. The dam foundation and abutment rock may contain open joints due to stress relief and near-surface ice-wedging. How- ever, it is expected that acceptable foundation rock can be reached with limited excavation. Therefore, the foundation rock was judged adequate to support the loads of either a concrete gravity or rockfill dam. The climatic conditions are such that the mean annual temp- erature is below freezing and maximum ice build-up during the winter season is expected to be three to five feet. Several types of rockfill dams were considered for the site. -A conventional rockfill dam with central impervious or semi-impervious core was eliminated due to a lack of significant clay deposits in the study area. Rockfill dam alternatives with upstream membranes constructed of 1) asphalt, 2) reinforced con- crete, and 3) synthetic or high density polyethylene were con- sidered. The asphaltic upstream membrane was eliminated. due to the high cost of mobilizing the required construction plant and the membrane's expected poor performance under repeated cycles of freezing and thawing. The reinforced concrete upstream face was eliminated because firm foundation support in upper portions of the left abutment is absent due to the expected depth of overburden. The upstream synthetic membrane was eliminated because it becomes brittle under subfreezing temperatures and the membrane's low surface friction creates construction prob- lems during bedding and riprap placement. A rockfill dam with a central synthetic membrane was found to be feasible, since most of the upstream shell material would be above freezing tempera- ture. Most of the lower two-thirds of the downstream shell would be below freezing, whereas, the upper one third would be subjected to fluctuating temperatures above and below freezing. Two types of concrete dams were considered: 1) concrete gravity and, 2) roller compacted concrete (RCC). The estimated construction cost for both types of concrete structures were compared for a range of dam heights and the RCC cost signifi- cantly less. The cost advantage is associated with precast upstream and downstream facing (which reduces form work and labor requirements) and rapid construction (since the mixture is compacted in one-foot layers with rolling equipment). III-9 The RCC structure was selected from the comparison studies. However, the RCC structure does not exhibit a significant cost advantage over a rockfill dam with a central synthetic membrane. Further investigation of the foundations and _ construction materials will be required during feasibility studies to select the dam type. Intake The intake structure, shown on Exhibit 24, would be located upstream from the dam on the left bank of the Allen River. This location affords satisfactory approach conditions. The sloped excavation of the approach channel would require support and erosion protection. The intake entrance would include trashracks and would be flared to provide a gradual transition to the 14-foot diameter power tunnel. The velocity through the trashracks at rated flow would be about 1.5 feet per second on the gross area, and the corresponding velocity in the power tunnel would be about 10 feet per second. The intake would be set below minimum reservoir level to maintain adequate submergence and limit the formation of frazil ice on the trashracks. Heated trashrack guides would be provided to ensure winter operation and an air bubbler system would be installed to inhibit sheet ice formation at the intake entrance. An ice boom would be provided at the Lake outlet to restrict the. movement of ice, at break-up, into the intake approach area. Bulkhead gates would be placed in the trashrack slots to allow the structure to be dewatered. The trashracks and bulk- head gates would be operated with the equipment provided in the intake house. Water Conductor The water conductor consists gf a tunnel and two branches. A profile along the centerline of the water conductor is shown on Exhibit 24. The overall length of the water conductor would - be 2,580 feet from the intake to the powerstation. The diameter was selected to maintain tunnel hydraulic losses in the range of three percent of gross head. The 14-foot diameter concrete lined tunnel would be about 2,480 feet long. The tunnel would branch upstream of powerstation into two 8-foot diameter con- crete and steel-lined tunnel sections. Each of the branches would be about 100 feet long and would connect to a turbine inlet valve. III-10 Diversion of Allen River flows during construction of the dam would be accomplished through the intake, power tunnel and a 400-foot long, 16-foot diameter, unlined extension of the power tunnel. The diversion tunnel outlet would be downstream from the powerstation on the left bank of the Allen River. Subse- quent to dam construction, the tunnel would be plugged down- stream from the wye branch. Routing studies for the diversion _ flood, with a 25-year return period and peak inflow of 14,000 cfs, were performed. The peak tunnel discharge was 1,800 cfs and the maximum lake surcharge elevation was El. 601. A coffer- dam upstream of the intake with a crest elevation at El. 603 would divert flows through the tunnel. Surge Control Facilities - Surge control facilities are required to limit pressure fluctuation in the water conductor under transient flow condi- tions. The most critical situations are: (1) starting the units, achieving synchronous speed, and synchronizing them into the electrical system, (2) controlling speed rise of the units if the entire station would be tripped off-line, and (3) restarting after a tripout. A surge chamber and riser, shown on Exhibit 24, would be excavated in rock and overburden and concrete lined. The surge facilities would be located 2,350 feet downstream from the intake. The maximum water surface elevation in the chamber with instantaneous load rejection (two units operating at full gate) and the minimum water surface elevation in the chamber (with one unit operating and instantaneous load acceptance of the second unit) were calculated using assumed unit characteristic curves. More detailed analyses will be undertaken in future studies. Powerstation The powerstation, shown on Exhibit 24, would be located on the left bank of the Allen River. The powerstation would be a located on the surface and constructed of reinforced concrete with an insulated roof sup- ported by a steel truss system. The superstructure would be about 130 feet long by 60 feet wide. III-11 The powerstation would contain two unit bays, an erection bay, and shop facilities. Personnel and equipment access would be from the east end. The two turbine-generator units would each consist of a horizontal Francis turbine with a maximum output of 6,900 hp at 90 ft of net head and a speed of 300 rpm. The generators would be directly connected to the turbines and would each be rated at 5,100 kVA, 0.90 pf, 60 HZ, three-phase. They would be totally enclosed, self-ventilated, and be complete with bearings and accessory equipment. The main transformer would be an oil- filled, self-cooled type, and located outdoors adjacent to the powerhouse. The powerhouse would be provided with a bridge crane of 30 ton capacity to handle the heaviest lift anticipated. The crane would be used to unload and erect equipment during construction and to facilitate maintenance. Access Chikuminuk Lake is only accessible by helicopter, float plane, and small boat from neighboring watersheds. Since the site is inaccessible by roads or navigable waters, project con- struction and operation would require the construction of an airfield to accommodate large airplanes. Heavy equipment and the construction camp would be airlifted to the site during the first winter season by building an ice runway on Chikuminuk Lake. Mobilization of the heavy equipment will allow construction of the permanent runway during the summer season. The permanent airfield would be located adjacent to the hydroelectric facilities and would consist of a single 150-foot wide, 5,000-foot long runway. Access from the airstrip to the powerstation switchyard, dam, and intake will require the construction of about two miles of gravel roads. The roads would be constructed on fill to preserve the natural surface mat of vegetation and organic materials. Careful attention would be given to drainage and erosion control. III-12 Switchyard and Transmission Line The generators would be connected to two power transformers located adjacent to the powerhouse. The switchyard would be located north of the powerstation. The switchyard equipment would consist of an oil circuit breaker, disconnecting switches, and instrument transformers. A single circuit 138 kV transmis- sion line would connect the project with the load center at Bethel. The transmission line routing, shown on Exhibit 26, would follow the south shoreline of Chikuminuk Lake to the Milk Creek Valley. From there, the line would cross the Wood River Moun- tains south of Kisaralik Lake and follow the Gold Creek and Kisaralik River drainages to Drum Lake. From there, the routing trends northwest, across Crooked Creek and Greenstone Ridge into the Kasigluk River drainage. The route leaves the foothills of the Kilbuck Mountains about 12 miles east of Three Step Mountain and trends northwest to Kwethluk. At Kwethluk, the route trends north to Akiachak, crossing the Kuskokwim River at Kiktak Island. From Akiachak the route trends southwest to Bethel along the west bank of the Kuskokwim River to a substation near the existing Bethel Utilities Corpo- ration generation plant. The substation would step- ~down the transmission voltage to 34.5 kV for distribution. The basic transmission line parameters are as follows: Type: I-type lattice guyed structure Voltage: 138 kV, 3 @ Conductor: 795 kcMil, ACSR Shield Wire: None Span Length: 1,000 feet The structure type, shown on Exhibit 26, was selected consider- ing the existence of permafrost, lack of ‘access roads, limited or no accommodations for construction crews, and marshy and mountainous terrains. The guyed lattice I-type structure is best suited for this type of environment because of minimal foundation work and its light weight. For a 138 kV I-type structure, the weight is estimated to be 2,500 lbs. Because of its relative light weight, this structure can be assembled at a marshalling yard together with attached guys and insulators and airlifted to the site by a helicopter where it can be quickly placed and guyed. Guyed structures have an ex- cellent performance record in climates with severe freeze-thaw cycles and in marshy and mountainous areas. III-13 Conductor stringing would be done using pulling-tensioning methods for fast production. Stringing equipment and conductors would be delivered by helicopter. The I-type structure and construction methods considered would preclude the need for construction roads and limit the width of the line corridor. Implementation and Construction Schedule Exhibit 27 presents the implementation schedule for the Chikuminuk Lake hydroelectric project from initiation of feasi- bility studies to start-up. The total duration would be approx- imately six and one-half years, assuming no lapse between phases. Four years would be required for: feasibility studies, preparation of the Federal Energy Regulatory Commission (FERC) license application, the evaluation by FERC, other State and local applications and approvals, detailed engineering design, and specification of major equipment. Project construction is estimated to take two and one-half years. The construction labor force would live at the site. The living quarters would be established in areas which would mini- mize impact on the surrounding area. All refuse and human wastes would be removed from .the site. A system of trenches and settling ponds would be provided around major construction zones and stockpile areas to intercept natural runoff and waste from construction processes which may contain sediments. Such sediments will be combined with stock- piled overburden and distributed over areas disturbed by con- struction to encourage revegetation. The products of construction such as excavated materials would be incorporated into the permanent project features to the maximum extent possible. Project Costs Construction Cost The construction cost of the project is estimated to be $127,000,000. The construction cost, at the December 1, 1982 price level, includes. direct costs, an allowance for contingen- cies, and engineering and owner's overhead. Table III-3 summarizes estimated construction costs. The detailed costs are presented on Exhibit 28. III~-14 The estimated direct costs of civil items include construc~ tion materials, equipment, transportation, and labor, and were based on quantity takeoffs. For.each construction item, a con- struction method was assumed. The quantity of labor, equipment, and material required was estimated. Total civil costs were calculated by adding the indirect costs and profit to the direct civil costs. Where applicable, unit prices were computed by dividing the total costs by esti- Iated quantities of work to be done. . Indirect costs are the contractor's costs that are not directly chargeable to specific work items, such as field office expenses, shop and warehouse construction and operation, manage- ment, supervisory and engineering salaries, taxes, insurance, bonds, and home office overhead. IITI-15 FERC Acct. No. 330 331 332 333 334 335 336 352 353 354 263 i/ Table III-3 ESTIMATED CONSTRUCTION COST OF THE CHIKUMINUK LAKE PROJECT (December 1, 1982 price level) Item Amount Land and Land Rights Powerplant Structures and Improvements Reservoirs, Dams and Waterways Water Wheels, Turbines and Generators Accessory Electrical Equipment Miscellaneous Powerplant Equipment Roads, Railroads and Bridges Transmission Plant Structures and Improvements Station Equipment Towers and Fixtures Camp and Commissary Subtotal, Direct Cost Contingencies * (25% of Subtotal Direct Cost) Total Direct Cost Engineering and Owner's Overhead (17% of Direct Cost) Total Construction Costl/ Total construction cost excludes escalation during construction. III-16 ($1,000) 3,500 3,373 17,721 5,750 520 859 375 682 2,025 30,290 21,750 86,845 21,715 108,560 18,440 127,000 and interest Electrical and mechanical equipment costs were estimated based on previous experience with similar equipment, adjusted for type, rating, remote location, and special operating charac- teristics. The above civil direct costs, and electrical and mechanical equipment costs were added to obtain the subtotal of direct cost. A contingency allowance of 25 percent is then added to obtain total direct cost. An allowance of 17 percent for engi- neering and owner's administration is added to the total direct cost to obtain total construction cost. Interest during con- struction and escalation are not included in the estimate. Operation and Maintenance Costs The estimated annual operation, maintenance, and replace- ment costs, at the December 1, 1982 price level, for the Chikuminuk Lake Hydroelectric Project would be $420,000. The costs are based on data published by the Federal Energy Regula- tory Commission, experience, and adjustments for the remote location of the plant. These costs include insurance, supplies, administration, on-site supervision, hydraulic and electric expenses, maintenance of the 138 kV transmission line, electric plant and other miscellaneous equipment, and an annual payment to a sinking fund for major repairs. Alternative Project A study was performed to evaluate the suitability of an alternative Chikuminuk Lake project which could provide:-a por- tion of the space heating demand. Project layouts and costs were made for a development that approaches the topographic limits of the site. This alternative project would have an rated capacity of 24 MW at a rated net head of 126 feet. It would produce 113.5 GWh on a firm basis and the average annual energy production would be 120 GWh. A listing of the pertinent alternative project. data is shown on Exhibit 30 and the general plan and profile and sec- tions of project features are shown on Exhibits 30 and 31. Table III-4 summarizes estimated costs for the construction of the project. The estimated annual operation and maintenance and replacement costs would be $685,000. III-17 Table III-4 ESTIMATED CONSTRUCTION COST OF THE CHIKUMINUK LAKE ALTERNATIVE PROJECT (December 1, 1982 price level) FERC Acct. No. Item Amount ($1,000) 330 Land and Land Rights 7,500 331 Powerplant Structures and Improvements 4,895 332 Reservoirs, Dams and Waterways 31,687 333 Water Wheels, Turbines and Generators : 10,500 334 Accessory Electrical Equipment 750 335 Miscellaneous. Powerplant Equipment 1,344 336 Roads, Railroads and Bridges 315 352 Transmission Plant Structures and Improvements 967 353 Station Equipment 3,350 354 Towers and Fixtures 30,290 263 Camp and Commissary 24,400 Subtotal, Direct Cost . 115,998 Contingencies : (25% of Subtotal Direct Cost) 28,992 Total Direct Cost 144,990 Engineering and Owner's Overhead (17% of Direct Cost) 24,610 Total Construction Costl/ 169,600 1/ Total construction cost excludes escalation and interest ~ during construction. III-18 Chapter IV POTENTIAL ENVIRONMENTAL IMPACTS A detailed description of the existing environment at Chikuminuk Lake is contained in Appendix D-3. The following discussion pertains to the potential environmental impacts associated with the development of a hydroelectric project at Chikuminuk Lake. Summary The cChikuminuk Lake Hydroelectric Project likely would entail the following environmental impacts: ° Visual impacts from the dam, powerhouse, airstrip, transmission line, and reservoir drawdown. ° Inundation of some lakeshore and feeder stream habitat and loss of local wildlife. ° Loss of fishery habitat and reduced populations in Chikuminuk Lake. ° Temporary minor decline in water quality of the lake .and downstream waters. ee ° Mortality to birds from transmission line collisions. ’ ° Conflict with existing land use in the state park. The primary concern will be for downstream fisheries, especially the sockeye salmon population that spawns in the Allen River delta area at Lake Chauekuktuli. However, with appropriate precautions, the downstream effects of the project can be minimized. There is potential for enchancement of down- stream fisheries. Although project impacts likely would not preclude development, the acceptability of the project is uncertain because it would be located in the Wood-Tikchik State Park and would conflict with the existing land use policies of conservation and recreation. Chikuminuk Lake Terrestrial Impacts Inundation. A 9.5 MW project would raise the lake level by about 12 feet and inundate an additional 3,800 acres. A 24 MW Iv-1 project would raise the lake level by about 62 feet and inundate an additional 8,700 acres. Many parts of Chikuminuk Lake are bordered by relatively steep terrain. Habitat loss in these areas, both in terms of quantity and quality would be minimal. The lake also is fed by a number of low lying streams (e.g. Milk Creek). In these streams, riparian habitat in lowland valleys would be lost to inundation. Field observations show that these lowland areas provide refuge for beaver, moose, black bear, brown bear, otter, mink, and ground squirrels. They also provide useful habitat for such transients as wolverine, fox, wolf, and, to a lesser extent, caribou. Additionally there are a number of low lying islands in the lake that would be inundated and one of the is- lands supports a rookery of glaucous-winged gulls. None of these species, nor the vegetative communities (up- land tundra, lowland tundra, willow, alder and cottonwood), are particularly rare in this region of Alaska. Riparian habitat makes up only a small percentage of the vegetation. Increasing the lake elevation would inundate a relatively small amount of vegetation and cause only local loss in abundance and frequency of the biota. Beaver and moose are probably the most sensitive species to inundation because they rely heavily on lowland habi- tats. Displacement of beaver, however, may be beneficial to some fishery habitats because beaver activity is extensive in the area around thé “Take>and has restricted flows in some streams. Thus, on a regional scale, inundation would not pro- duce significant impacts on the terrestrial ecosystem, but there will be local impacts due to loss of lowland habitat. Addition- al studies of shoreline habitats, topography, and biotic distri- bution patterns will be needed to more accurately assess the potential biotic losses. Downstream from the project, there should be no major effects on terrestrial habitats other than those lost to con- struction at the dam site. The habitat along the Allen River is not expected to change. Studies are needed to assess potential impacts-to riparian vegetation on the Allen River, but impacts are expected to be minor. There are no man-made structures in the area that would be affected by the project. An archaeological reconnaissance undertaken in 1980 revealed some artifacts at five sites around Chikuminuk Lake. A thorough field reconnaissance by an archae- ologist may be needed to assess the significance of these sites and to verify that no other historically important sites exist in areas affected by project development. IvV-2 Drawdown. Chikuminuk Lake levels would vary seasonally as a result Of filling and emptying cycles. Onshore anchor ice would subside with drawdown and accelerate erosive forces in the drawdown area and help uproot and dislodge inundated terrestrial vegetation. This would affect both aquatic and terrestrial environments. Shoreline degradation would affect terrestrial wildlife, especially those species that frequent the terrestri- al-aquatic interface such as beaver, otter, mink, and moose. Terrestrial impacts would be localized in the Chikuminuk Lake basin, however, and these species and their habitats are abundant in the region. Construction. Project construction and operation would require an airstrip capable of handling C-130 transport planes. No access roads would be built to the area and all construction personnel, equipment and materials would be airlifted to the site. Construction of an airstrip would increase the potential for public access to Chikuminuk Lake and adjacent areas. Cur- rently the area is accessible only by float plane or helicopter and small boats from adjacent lakes. Access would be far more limited by construction of an airstrip than if an access road was developed from a coastal city such as Dillingham. Increased public access could be considered as recreational enhancement but, if realized, would mean increased pressure on the fish and wildlife resources. Poaching is also a possibility and could interfere with conservation goals of the Wood-Tikchik State Park. Additionally, during the construction period, con- struction crews can be expected to take local fish and game; however, this would be a short-term impact. Construction activity which removes surface vegetation from the slopes above Chikuminuk Lake or along the Allen River would be a source of erosion and sediment. Highly saturated soils of the area would present special problems regarding erosion and landslides (see Appendix B, Chapter 2). Special precautions would be needed to control erosion and prevent runoff and sedi- ments from entering the aquatic ecosystem. Waste piles, borrow areas, and disturbed sites would impact areas around the dam site. These would need to be reclaimed via revegetation or other methods in accordance with state law. Two major hazards from petroleum products include fire and leaks or spills. Fire could threaten the well being of person- nel and terrestrial habitat. Leaks or spills would be most serious if they entered the aquatic ecosystem. All petroleum products, especially large caches of diesel and jet fuels, would be stored in special containment facilities. IV-3 Use of heavy diesel equipment, aircraft, motor vehicles and operation of a construction camp would introduce a variety of air pollutants locally in relatively low concentrations. Air pollutants are not expected to present any serious, or lasting, environmental impacts. Even so, some local visual impacts in the form of ° smoke, plumes or haze may be expected in calm weather during the construction period. If construction occurs during colder months, ice fogs are possible. It will be difficult to avoid these occasional minor visual impacts. Impacts from noise are expected to be local, relatively minor, and will have no long lasting effects on the environment. Noise from construction activities can be expected to drive away most of the wildlife that might otherwise occupy or utilize the construction areas. Blasting, if utilized, could be detrimental to species attempting to nest or raise young. Field reconnais-— sance indicates that raptors do not nest near the proposed dam site; however, big game species including moose and bear were seen in the area. Raptors may nest along the transmission cor- ridor. Prior to construction activities, the transmission line corridor should be scouted for potential nest and den sites. Any critical sites should be avoided by appropriate timing of construction or rerouting of the corridor. Sanitary waste and trash from the construction camp could introduce both visual and biotic impacts to the area. Addition- ally, the camp and staging areas would destroy some habitat over and above that needed for the dam and facilities. State laws require that, upon completion of construction, the staging areas and camps be returned to their natural state. The project design would include measures for erosion control, containment and removal of all wastes during and after construction, and a general reclamation program. Visual Impacts. A hydroelectric project would create three permanent visual impacts: 1) the facilities and structures at the lake (dam, powerhouse, roads, airfield, etc.); 2) the transmission line and substations between the project site and delivery point at Bethel, and 3) exposure of the shoreline during periods of low lake levels. Additionally, there would be the temporary visual and aesthetic impacts from construction activities, equipment, and facilities. Impacts from the dam and project facilities would be local. Impacts from permanent facilities can be minimized if they are placed out of view or made to blend in with their surroundings. The transmission line would traverse 130 miles to Bethel. Appropriate routing of the transmission line would help diminish Iv-4 rm _) the visibility of the 60 foot high tranmission line towers. The towers would exceed the height of the tundra vegetation. The visual impacts from reservoir drawdown would be related to the time, duration, and extent of low water periods. Small daily fluctuation in the reservoir level would produce only minor visual impacts. The seasonal minimum drawdown would occur in winter. At this time, ice covers the lake and deep snow covers the ground; recreational visitation would be at its lowest level. Anchor ice would scour the shoreline in winter and would affect the final visual aspects and biotic conditions of both terrestrial and aquatic shoreline habitats. Aquatic Impacts Chikuminuk Lake appears to be a typical northern oligo- trophic lake. It is relatively deep with a small proportion of shallow water areas confined to a narrow shelf around the shore- line. The shoreline consists mostly of gravel and cobble that probably serve as important spawning beds for lake trout and Dolly Varden. A few feeder streams to Chikuminuk Lake also appear suitable as spawning and rearing habitat for Dolly Varden and Arctic grayling. The actual location and abundance of spawning and rearing areas for all three species would be deter- mined through more detailed studies (see Proposed Studies, below). . Lake fish likely would utilize newly created shallows; however, the shallows would be different from existing habitat until natural processes of erosion and sedimentation recreate gravel and cobble bottom habitats along the new shoreline. Assuming that newly created shallows would be suitable for fish habitat, drawdown of the lake could create further impacts by dewatering the shallows and by the subsidence of anchor ice in winter. Impacts to fisheries would occur to the extent that shallows are utilized for spawning and rearing areas. Accelerated scouring and erosion could provide a long ‘range advantage to fish populations by more rapidly recreating suit- able spawning areas (cobble and gravel). However, it would have short-term disadvantages because it would impact those fish whose eggs incubate over winter in the drawdown area. Summer and fall spawners such as Dolly Varden and lake trout would be most vulnerable because lake levels would be highest during spawning time. Eggs laid in the drawdown area would be lost to anchor ice in winter or by desiccation. Lake trout may avoid some drawdown effects because they can spawn in deep water. Iv-5 Allen River Water Quality Introduction of sediment to the Allen River could affect _. water quality and downstream fisheries. Construction of the cofferdam is scheduled for March-April when incubating eggs would be ready to hatch downstream. Because fill would be placed in the river, this could be a critical phase. The borrow materials are not expected to contain large amounts of fine sediments nor any contaminants; however, prior testing of the materials may be required. Construction of the diversion tunnel may also introduce sediment into the Allen River. Tunnel spoil may be suitable material for construction of the dam or other features. It may also be possible to utilize the material for artifical Spawning areas in Chikuminuk Lake or the Allen River. Downstream Flow Variation Hydrologic data indicate that there is considerable season- al variation in the natural flow of the Allen River. The aver- age annual flow is 1400 cfs. The average summer flows range between 2090 and 4000 cfs and average winter flows range between 300 and 600 cfs. The hydroelectric project would smooth these seasonal extremes and mean monthly flows would approach the mean annual flow. The increased- winter flows may enhance survival of overwintering eggs by eliminating low flows and freezeups. The projects, however, would introduce daily flow variations of between 800-1600 cfs (9.5 MW) or 1300 ta 2600 cfs (24 MW). Salmon spawn in abundance in the lower Allen River delta at Chauekuktuli Lake from June-September. Sockeye are the most abundant species but pinks,- chinook, and probably coho also are present. Dolly Varden also probably spawn there in the fall and Arctic grayling in the spring. Planned minimum releases with the project would be greater than minimum flows under natural conditions and likely would permit spawning to continue. A primary concern would be that daily variations in flows do not dewater any critical habitat or change the fish hehavior. If daily fluctuations are too extreme, they could strand fish or eggs in dewatered side channels. The majority of the fish appear to be near the downstream end of the river; however, suitable habitat probably exists throughout much of the river. The potential for impact would depend on dampening effects of distance on flow fluctuations and actual habitat use. More detailed studies are needed to determine the change in wetted stream areas and where fish spawning and rearing habitats occur IvV-6 in the Allen River. These studies would establish flow regime criteria. Downstream Temperatures Wintertime water temperatures in the Allen River are prob- ably near 0°C throughout most of its length. Water entering from Chikuminuk is probably only slightly warmer, although it could be as warm as 3 to 4°C. The project would draw water from greater depths than normally flow into the Allen River, hence warmer temperatures would be discharged downstream. Should such warmer water reach incubating fish eggs in the lower river, it could accelerate their normal development time and lead to increased mortality due to premature hatching. Such occurrence would depend on: .a) the temperature regime of flow from the lake; b) where the incubating eggs are actually laid; and c) whether the process of heat loss in the river can overcome the initial increase in temperature. Given the extremely cold ambient air temperatures, it appears likely that if there is an increase in temperature from a deep water intake, the river water would rapidly cool to its normal ambient level of near 0°C. This probably would occur within a short distance downstream from the powerstation. It also appears likely that the upper reaches of the Allen River (near the dam) are not heavily used for spawning. It thus seems likely that minor temperature variations would not affect downstream fisheries during the water. Summertime conditions in subpolar lakes have surface tem- peratures above 4°C for only short periods. Additionally, temp- erature gradients, if present, are poorly developed and usually near the surface (Hutchinson, 1957:437). Data collected in August 1982 indicate that only a very short gradient develops in Chikuminuk Lake. Water entering the Allen River was quite cold (near 5°C) and remained cold for most of its length. Thus, diversion of 4°C water in summertime from a water intake will not likely affect downstream temperatures or fisheries. Oxygen levels are expected to be quite high in both summer and winter flows because cold waters usually have relatively high dissolved oxygen levels. If future detailed studies show any unexpected characteristics in thermal or 09 properties, it may be necessary to consider multilevel intakes to better con- trol downstream water quality for a 24 MW project. It is not possible to consider multilevel intakes in a 9.5 MW project be- cause the intake would be drawing water from as shallow a depth as is technically possible. IV-7 Fish Passage Upstream migration of fish into Chikuminuk Lake is blocked by a series of natural rapids below the dam site. As a result, salmon currently are absent from Chikuminuk Lake. Out-migration from Chikuminuk Lake through the Allen River, if it occurs, is restricted to the endemic species now in the. lake which include Dolly Varden, grayling and lake trout. Fishery studies would be needed to establish whether sub- stantial numbers of fish congregate near, or move into, the Allen River from Chikuminuk Lake; however, it is unlikely that any large numbers of fish will be entrained into the power tun- nel because of the relatively low intake velocities planned. If salmon were to be artifically introduced to Chikuminuk Lake, then special design considerations might be needed to permit downstream migration. Alternatively, coho salmon could be introduced as a land locked fishery (see Potential for Avoid- ance, Mitigation and Enhancement). — Transmission Lines Impact on Birds Tall structures would be a collision hazard for. birds. This includes transmission line towers, guy wires and conduc- tors. A large variety of factors are involved in understanding how and why birds collide with transmission lines (See Exhibit 32). Species with the following characteristics are more vul- nerable to collison: large body size, low maneuverability, low altitude flight patterns, and flight during low visibility. Waterfowl and raptors that occur in the Bethel and Chikuminuk areas have several of these characteristics. The Bethel area has-extensive waterfowl nesting areas and migratory corridors. Summer ground .fogs. are common and could increase mortality from collisions if a transmission line system is con- structed. As evidence for this prediction, more than 100 dead ptarmigan were collected last spring under a short existing stretch of intertie near Bethel (Reiswig, pers, common., U.S. F.W.S.). King (1982) and Strickland (1982) have communicated similar cases of bird mortality along the same stretch of in- tertie. Additionally, certain parts of the Kilbuck Mountains serve as nesting areas for several species of raptors including golden eagles. Here the 138 kV transmission line that would link the Chikuminuk Lake project with Bethel may pose both a collision and electrocution hazard. An important issue is how much additional mortality is likely to occur from the transmission line. Experts suggest IvV-8 that, taken as a whole, avian mortality from transmission lines is very small and probably inconsequential in terms of mainten- ance of populations of most species (Avery and However, 1978). There are exceptions, however. Kroodsma (1978) reported that about 10% of all known reported deaths in hald eagles (lower 48 states) came from transmission line impacts. In the case of raptors, the loss of even a few breeding pairs of relatively rare species (e.g. falcons, eagles, etc.) could have important biological consequences. Furthermore, the Bethel area repre- sents an unusual concentration of sensitive nesting hird spe- cies. There is the additional likelihood of public concerns over those species which have a national prominence. The waterfowl of this region represent a primary source of recruitment for the entire North American continent. They also provide an important source of food for the local subsistence economy. In the event that a centralized energy supply plan is selected, one that utilizes an extensive intertie and transmission system, it will be necessary to carry out more detailed field studies on the distribution, abundance, and flight patterns of some of these species. With proper design and routing, it may he possible to minimize mortality from transmission lines and thereby prevent significant impacts to area bird populations. Visual Impacts The transmission lines would consist of a 138 kV line that would traverse approximately 130 miles from Chikuminuk Lake to Bethel. The towers would he approximately 60 feet in height and would be spaced at five per mile. The route to Bethel would traverse parts of the Wood-Tikchik State Park cross the Kilbuck Mountains and the Yukon Delta National Wildlife Refuge... In rough terrain, it would be possible to minimize visual impacts (and potential for collison) of the 138 kV line by appropriate routing along cliff faces and away from direct lines of sight. This would not be possible in most of the region because of the flat terrain and low tundra vegetation. The Wood-Tikchik State Park will probably be the most sen- sitive area because of its natural aesthetic qualities and use for recreation. Certain areas in the Kilbuck Mountains, including the Kisaralik and other drainages and parts of the Yukon Delta Refuge that are used for recreation and other pur- poses would also be sensitive areas. Iv-9 Other Impacts Transmission lines pose two other hazards, one environmen- tal and one safety. To the extent that the lines are used as visual navigation aids, they may invite greater access to now remote areas. Although no access roads are planned, off the road vehicles and aircraft could use them to navigate in remote areas. The transmission lines could also pose an aircraft colli- sion hazard. Most small aircraft pilots navigate by visual means at moderate to low altitudes and poor visibility is common in the region. Land Use Conflicts Wood-Tikchik State Park The proposed Chikuminuk Lake hydroelectric site is located within the boundaries of the 1.4 million acre Wood-Tikchik State Park. The park, located approximately 300 miles southwest of Anchorage, is bounded on the west by precipitous slopes of the Ahklun and Kilbuck Mountains, on the east and north by the Nushagak lowlands, and on the south by Lake Nunavaugaluk. Most of the park is remote wilderness; few areas exhibit the presence of man. The park is remote, and access is gained only through char- ter air services and shallow draft boats. No visitor statistics are kept for the park, but are estimated at 20,000 visitor-days per annum (Div. of Parks, 1974). Visitation of Chikuminuk Lake is probably only in the magnitude of hundreds of visitor-days per year. Use rates would likely remain low as long as an access road is not constructed. The park was established by the State legislature on June 29, 1978 expressly to "... protect the area's fish and wildlife breeding and support systems and to preserve the continued use of the area for subsistence and recreational activities..." and "... to protect the area's recreational and scenic resources..." (AS 41.20.460). While nothing in the enabling legislation, Alaska Administrative Codes, or statutes expressly prohibits hydroelectric development on park lands, development is in con- flict with the normal role envisioned by the legislature for such reservations. State parks are defined as "... areas with special recreational, scenic, cultural, historical, wilderness, or similar values..." that are "...to be managed primarily for the public use and enjoyment of these values". (AS 38.04.070). Iv-10 The decision of whether a proposed development is compati- ble with park management rests with the Director of State Parks. The director has broad discretionary powers and may permit development to take place if he determines that: 1. ecology of state park lands will not be irreparably damaged or imperiled; : 2. state park lands are protected from pollution; 3. public use values of the state park are maintained and protected; and 4. public safety, health, and welfare will not be damaged or. imperiled". (11AAC 18.010). Note that the terminology of these directives provides the director freedom of action and he may permit a given development to proceed provided that, in his judgment, the development does not materially detract from the attributes of the park. Development proposals are likely to come under close public scrutiny. The eventual decision of whether to proceed with the Chikuminuk hydroelectric. project would rest with public precep- tions of land use values and decisions. These in turn will be influenced by the various costs and benefits of different energy supply plans for the region, from an economic and environmental point of view. Refuge Lands A portion of the transmission corridor for the Chikuminuk Hydroelectric Project would be located in the Yukon Delta National Wildlife Refuge. As in the state park lands, there will be potential conflicts in land use values, especially in conservation areas. Native Lands The Alaska Native Claims Settlement Act (ANSCA) has allo- cated substantial tracts of land in the Bethel region for selec- tion by native village and regional corporations. Those tracts of entitlement lands that have heen selected by the native cor- porations will he unavailable for a transmission line corridor except by formal agreement. These lands have heen selected primarily for their cultural and economic values, including subsistence use of resources. Therefore any development on these lands may affect their intrinsic value and would likely be unacceptable. For instance, since the transmission line may Iv-11 impact waterfowl populations in the Delta, it may not be accept- able to subsistence users. Potential for Avoidance, Mitigation and Enhancement ’ Unavoidable Impacts The following environmental impacts will be unavoidable consequences of Hydropower development at Chikuminuk Lake: ° Decrease in the lake fish populations of trout, char, and grayling. ° Loss of terrestrial habitat and wildlife from inunda- tion. ° Shoreline degradation and loss of shallow aquatic habitats from inundation and drawdown cycles. ° Visual impacts from various aspects of the project including the dam and facilities, drawdown area, and transmission lines. ° Increased bird mortality from the transmission line, especially around the Bethel lowlands. Mitigation It may be possible to minimize some of the impacts. For éxample, fisheries may be enhanced by vegetation clearing, crea- tion of artificial spawning areas, or stocking programs. Trans- mission line impacts may be minimized by routing and design improvements. Terrestrial habitat losses could be mitigated partly by reclamation, and partly by land exchange agreements to increase state park boundaries in other areas. It will be possible and important to avoid impacts to down= stream fisheries, water quality, and habitat during construc- tion, by standard preventative measures, and during operation, by limiting daily flow fluctuations. Of particular concern will be the sockeye salmon fishery at the Allen River beach at Lake Chauekuktuli. Initial studies suggest that minimum flows needed for power would be sufficient to maintain downstream habitat quality and may potentially improve survivorship of incubating eggs by increasing normally low winter flows. Enhancement Chikuminuk Lake probably has the biological potential to support a sockeye salmon fishery; however, the feasibility of Iv-12 ob such a project, especially under the planned hydropower operat- ing regime, must be viewed from both economic and environmental perspectives. Fish passage facilities would be required at the dam and possibly at a set of rapids downstream from the dam. Additionally, a fish hatchery might also be needed to stock the lake. Hatcheries and fish passage “facilities require large investments. Possibly the inclusion of a land locked coho salmon fishery could be considered. From an environmental perspective, the drawdown regime would probably diminish the potential for success of a salmon fishery in the. lake, and juvenile sockeye might affect, or be affected by, the existing lake fisheries because of increased competition for food. An important question that would need analysis would be whether a successful, introduction of salmon into Chikuminuk Lake would provide a favorable benefit cost vatio and make a significant contribution to the salmon fishery in Bristol Bay. Proposed Environmental Studies and Monitoring Programs Observations and impressions regarding the environmental acceptability of a hydroelectric project suggest that there would be visual, aquatic, and terrestrial impacts. If a feasi- bility study is warranted, a number of environmental studies should be initiated. These are summarized below: ° Fishery Studies: To establish existing population Sizes and spawning habits in Chikuminuk Lake and Allen River, and the potential for fishery mitigation and enhancement. ° Water Quality Monitoring Studies: To insure mainten- ance of existing water quality during and after con- struction, especially in the Allen River. ° Hydrologic Modeling Studies: To establish downstream . affects from alteration of flow regimes in the Allen River. ° Migratory Bird Studies: To establish the potential for mortality from transmission lines, particularly near Bethel but also in the highlands. ° Vegetation and Wildlife Studies: To establish the heed for vegetation clearing in the inundation zone and to develop a revegetation plan for disturbed areas. IV-13 ° bye Recreational Studies: To minimize visual and aes= thetic impacts, maximize the recreational potential of ‘the project, and assist in the reclamation plan. Archaeological Survey: To establish the location of any historically important sites near the project. IV-14 1. 26 4. 5. 6. 7. REFERENCES Alaska Department of Natural Resources, Division of State Parks, 1974. “Comprehensive Master Plan for the Proposed Wood-Tikchik State Park, Anchorage", Alaska, 55 pp. Avery, M.L. and K.D. Hoover, 1978. "Impacts of Transmis- sion Lines of Birds in Flight." Proc. Workshop, Oak Ridge, Tenn. Biol. Ser. Program. FWS/OBS-78/48, Govt. Print. Office. Hutchinson, G.E., 1957, A Treatise on Limnology. Vol. I, Wiley & Sons, N.Y. King, J.G. (1982, Interview with AEIDC), May 12, 1982, Juneau, Ak. Kroodsma, R.L., 1978. "Evaluation of a proposed transmis- sion lines impacts on waterfowl and eagles." In, Avery and Hoover, Impacts of Transmission Lines on Birds in Flight. Proc. Workshop. Oak Ridge, Tenn. Biol. Serv. Pgm. FWS/OBS-78/48, Govt. Print. Office. Lee, J.M. Jr., 1978. "Effects of a transmission line on _ Bird flight: Studies of Bonneville Power Administration Lines." In, Avery and :Hoover, Impacts of Transmission Lines on Birds in Flight. Proc. Workshop. Oak Ridge, Tenn. Biol. Serv. Pgm. FWS/OBS-78/48, Govt. Print. Office. Reiswig,' B. 1982. Telephone convservation with AEIDC, June 10, 1982. U.S. Fish and Wildlife Service, Bethel, Ak. Strickland, C. 1982. Interview with AEIDC, March 10, 1982. Bethel, Ak. Pp . by teed tae | | | | | 1 Lake ay E_ Ar - Les SAB a Discovery ~~ yet y TULUKSAK RIVER 4 the Ring, g @ FOG RIVER » iver Se he = é fom > Ce ge Eek Y , ‘ a ne Lay far bake KISARALIK RIVER ® oa (GOLDEN GATE FALLS) a NB. » SALMON RIVER i a KIPCHUK RIVER = $ s é & i KISARALIK RIVER (LOWER FALLS) Ne NLake NY se ns ‘ 5 ee ane bh | = en lane e e a hie nh” é an UPNUK LAKE © 3 aes Ta. + be . aut’ * a eee 3 n “€ ‘Chickitminuk os Et : we MILK CREEK (LOWER SITE) @ . ir ee re Riana ; MILK CREEK (UPPER SITE) -@hscode ! 9 CHIKUMINUK LAKE * Heort Rees Nea Lake’: Ee ie Tikchik-bake oe Nuys, fd VICINITY MAP NOTE: Base mapping prepared by the Arctic Environmental Information and Data Center, University of Alaska. 0 20 40 SCALE IN MILES (1: 1,000,000) ALASKA POWER AUTHORITY ~ BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT LOCATION MAP POTENTIAL HYDROELECTRIC SITES HARZA ENGINEERING COMPANY December 1982 175 R CONSTRUCTION COsT — $106 8 a NOTE: Price level December 1982, construction cost exciudes escalation and interest during construction. = = RALIK f ; ~ RIVER mt NY \ 3 ; 7 KISARALIK |RIVER (UPPER FALLS) | _ : Y || Afri LO IKUMIN' 7 \ .\ \ \ x 5 - Mesverraes RIVER LS) 10 15 20 INSTALLED CAPACITY IN MW_ ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT eee PCR Tee) a erel INSTALLED CAPACITY VS. CONSTRUCTION COST HARZA ENGINEERING COMPANY eo EXHIBIT 3 bby ~ U.S.G.8 Drainage Pam Crest Maximum Dam Normal Maximum Total Tunnel Diameter Spillway Capacit: Quadrangle Area Elevation Height Reservoir Fluctuation Diversion High Head Low Head PHF Peak Design Flood Project Name (1:63,360) (8g. mi.) (¥e.) (Ft.) Elevation (Fe.) (Ft.) (et.) (Ft.) (cfs) (cfs) ‘TAYLOR : 620 115 598 oO 11.0 13.0 115,000 ‘Chikuminuk Lake MOUNTAINS 348 640 135 620 12 19.0 10.5 12.5 287,000 100,000 A-B 660 . 155 640 22 10.0 12.0 100,000 870 100 850 28 16.5 15.5 341,000 920 i590 900 32 25.0 11.5 12.5 341,000 330,000 Kisaralik River BETHEL 500 970 200 950 . 38 10.0 11.0 280,000 (Lower Falls) B~3 : . 795 115 7715 . 28 14.0 14.5 + 320,000 Kisaralik River BETHEL 550 870 190 850 45 25.0 10.0 12.0 356,000 280,000 (Golden Gate Falls) c-4 920 240 900 f 50 9.0 11.0 265,000 1070 135 1050 40 11.5 14.0 254,000 . 1120 185 1100 46 10.5 12.0 254,000 Kisaralik River BETHEL 271 1170 235 1150—Ci«; | 50 19.5 9.0 11.0 254,000 254,000 (Upper Falls) B-3 1070 ‘ 140 21050 40 12.0 14.5 195,000 Kipchuk River BETHEL 120 1120 185 1100 46 16.5 10.5 12.0 230,000 165,000 D-1 1170° 240 1150 50 9.0 11.0 140,000 ais 40 800 15 10.0 - . 49,000 . TAYLOR 835 60 820 35 30.0 - 154,000 46,000 Upnuk Lake MOUNTAINS 105 850 75 835 . so 12.0 10.0 - 43,000 ALASKA POWER AUTHORITY . : BETHEL AREA POWER PLAN ' FEASIBILITY ASSESSMENT THIRD SITE SCREENING PROJECT DATA : . HARZA ENGINEERING COMPANY 1 , , f , Y y 7 = ' \ i : ; \ { i ' : aml 1a? | | i Coss. ‘ ACCESS ROAD ‘ \ ANS } a, BRIDGE / ? o\ ' Fd . ANNAN Bes se ™r ene Noe SJ : em es ~“ ¢ 4 re “ > $ (Ss. - yy ~ - , te = $f o NI a 1 /# ‘ sto vue * £7 oo CHIKUMINIK a 4 LAKE = ‘ 660 FLOW \ i\ Ne SPILLWAY SCALE 0 400 800 FEET Lt 1” = 800° NOTE: oy Base: map topography enlarged from : USGS. Quadrangle: sheets 1:63,360 series. boy aa ROCKFILL DAM ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT THIRD SITE: SCREENING. CONCEPTUAL PROJECT PLAN CHIKUMINUK LAKE HARZA. ENGINEERING COMPANY VICINITY MAP a Le S + 1500 SPILLWAY DIVERSION TUNNEL - - TAILRACE TUNNEL ~ ACCESS ROAC ACCESS: TUNNEL. POWERSTATION POWER TUNNEL SCALE 0. 400 800 FEET ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN _ PEASIBILITY ASSESSMENT 1°= 800° NOTE: THIRD SITE SCREENING CONCEPTUAL PROJECT PLAN KISARALIK RIVER LOWER FALLS; Base map:topography enlarged from USGS Quadrangle sheets 1:63,360 series. HARZA ENGINEERING. COMPANY ‘bb HIBIT € TAILRACE TUNNEL UNDERGROUND POWERSTATION, —_ TUNNEL | DIVERSION WV ( / ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT THIRD SITE SCREENING CONCEPTUAL PROJECT PLAN KISARALIK RIVER GOLDEN GATE FALLS HARZA ENGINEERING COMPANY SCALE 0 400 800 FEET a | 1“ = 800° NOTE: | Base map topography eniarged from USGS Quadrangle sheets 1:63,360 series VICINITY MAP ACCESS ROAD SPILLWAY N , ROCKFILL DAM 4059 BRIDGE — TAILRACE TUNNEL NANOS : ACCESS TUNNEL UNDERGROUND POWERSTATION Me POWER TUNNEL ——~ - DIVERSION. TUNNEL N "by BETHEL AREA POWER PLAN. FEASIBILITY ASSESSMENT SCALE. 0 400 3800 FEET Ll Ld, 1" = 800" THIRD SITE SCREENING ‘ CONCEPTUAL PROJECT PLAN KISARALIK RIVER UPPER FALLS NOTE: Buse map topography eniarged from HARZA. ENGINEERING COMPANY USGS Quadranale sheets 1:63.260 series. "= wGlen 1700 1600 TAILRACE TUNNEL~—a —/ / 7” yp — evant TUNNEL ROCKFILL DAM: me 1000 1008 ACCESS ROAD SPILLWAY SCALE 0 400 800 FEET Leeteeelanneeteneen 1“ = 800° NOTE: Basemap. topography enlarged from USGS Quadrangle: sheets 1:63,360 saries. bys \ EXHIBIT 8 VICINITY MAP UNDERGROUND POWERSTATION VN ROCKFILL DAM ACCESS TUNNEL . ALASKA POWER AUTHORITY BETHEL AREA. POWER PLAN FEASIBILITY ASSESSMENT THIRD SITE SCREENING , CONCEPTUAL PROJECT PLAN. KIPCHUK RIVER — HARZA ENGINEERING COMPANY’ ed 47 420° 1150 S 1700 —— 10: 400° 950 » UPNUK LAKE = co ne ii ea L ~ ie | DIVERSION AND LOW LEVEL OUTLET WORKS POWERSTATION SCALE 0 600 1200 FEET NOTE: | el 1 | Base map topography enlarged from USGS Quadrangle sheets 1:63,360 series go Damsite = | \ See ee Airstrip ~ 2 ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT THIRD SITE SCREENING CONCEPTUAL PROJECT PLAN UPNUK LAKE HARZA ENGINEERING COMPANY December 1982 EXHIBIT 10 RESERVOIR ELEVATION — FEET 596 598 600 602 604 606 608 & RESERVOIR ELEVATION AVERAGE ANNUAL ENERGY — MWH/YR — x 1000 1175 118.0 1185 610 612 614 - 119.0 119.5 CONSTRUCTION COST — $ MILLION RESERVOIR ELEVATION — FEET ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT 3 x c = Z | > So : us = = re 117.5 118.0 118.5 CONSTRUCTION COST — $ MILLION NOTE: Price level December 1982, construction cost excludes escalation and interest during construction. THIRD SITE SCREENING CHIKUMINUK LAKE ENERGY GENERATION VS. CONSTRUCTION COST AND RESERVOIR ELEVATION HARZA ENGINEERING COMPANY . EXHIBIT 1tt~ RESERVOIR ELEVATION — FEET 850 860 880 . 900 920 940 960 - amen Foret TTT ical Lt —_| Pe ree | ELEVATION —4 ee Tt EE Tt 160 130 140 150 170. 180 CONSTRUCTION COST ~— $ MILLION AVERAGE ANNUAL ENERGY — MWH/YR x 1000 RESERVOIR ELEVATION — FEET FIRM ENERGY — MWH/VR x 1000 130 140 150 160 170 180 CONSTRUCTION COST —$ MILLION ALASKA POWER AUTHORIT? BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT \ THIAD SITE SCREENING LL KISARALIK RIVER LOWER FALLS | ENERGY GENERATION | VS. CONSTRUCTION COST AND RESERVOIR ELEVATION: | HARZA ENGINEERING COMPANY | NOTE: Price level December 1982, construction cost excludes escalation and interest during construction. EXHIBIT 1; RESERVOIR ELEVATION — FEET 770 780 800 820 840 860 870 el a eee | & AVERAGE ANNUAL ENERGY — MWH x 1000 = a 170 190 210 220 CONSTRUCTION COST — $ MILLION RESERVOIR ELEVATION — FEET FIRM ANNUAL ENERGY — MWH x 1000 130 150 170 190 210 220 CONSTRUCTION COST — $ MILLION ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT THIRD SITE SCREENING KISARALIK RIVER GOLDEN GATE FALLS ENERGY GENERATION VS. CONSTRUCTION COST AND RESERVOIR ELEVATION HARZA ENGINEERING COMPANY EXHIBIT 1° RESERVOIR ELEVATION — FEET — 1090 1110 1130 1150 8 = oe 3 ‘_ 3 3 AVERAGE ANNUAL ENERGY — MWH x 1000 120 140 160 180 200 CONSTRUCTION COST — $ MILLION RESERVOIR ELEVATION — FEET 1030 1050 1070 - 1080 1110. 1130 1150 1160 FIRM ANNUAL ENERGY — MWH x 1000 120 _ 140 160 . 180 200 220 240 CONSTRUCTION COST — $ MILLION ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT THIRD SITE SCREENING KISARALIK RIVER UPPER FALLS - ENERGY GENERATION i VS. CONSTRUCTION COST AND RESERVOIR ELEVATION HARZA ENGINEERING COMPANY NOTE: Price level December 1982, construction cost exciudes escalation and interest during construction. RESERVOIR ELEVATION — FEET 1050 1070 1090 78 CONSTRUCTION AVERAGE ANNUAL ENERGY — MWH x 1000 EXHIBIT 14 CONSTRUCTION COST — $ MILLION RESERVOIR ELEVATION — FEET 1030 1060 . 1070 1080 1110 1130 3 z CONSTRUCTION RESERVOIR = cost ELEVATION > = | ix 20 oo " 15 130 140 160 180 200 220 CONSTRUCTION COST — $ MILLION ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT NOTE: THIRD SITE SCREENING Price level December 1982, construction cost excludes escalation and interest during construction. KIPCHUK RIVER ENERGY GENERATION VS. CONSTRUCTION COST AND RESERVOIR ELEVATION HARZA ENGINEERING COMPANY December 1982 20 AVERAGE ANNUAL ENERGY — MWH x 1000 8 RESERVOIR ELEVATION — FEET 800 810 820 830 840 Pt [epee DE = co™ i PEROT TL \-—L- reservoir | | ELEVATION 175 180 185 190 195 . EXHIBIT 1: CONSTRUCTION COST — $ MILLION RESERVOIR ELEVATION — FEET 40 FIRM ANNUAL ENERGY — MWH x 1000 8 ‘175 1 800 810 820. _ 830 840 : RESER! ELEVA wy, Se | Se NP a 80 185 190 195 | CONSTRUCTION COST — $ MILLION NOTE: Price level December 1982, construction cost excludes escalation and interest during construction. ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT THIRD SITE SCREENING UPNUK LAKE ENERGY GENERATION VS. CONSTRUCTION COST AND RESERVOIR ELEVATION HARZA ENGINEERING COMPANY EXHIBIT 16 KISARALIK RIVER (GOLDEN GATE FALLS) ECONOMIC COST — CENTS / KWH 2a 3 32 u“ 3% 3 40 REGIONAL ENERGY REQUIREMENT SUPPLIED — MWh x 102 ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT ANNUAL ECONOMIC COST OF AVERAGE ENERGY HARZA ENGINEERING COMPANY Desember 1862 ECONOMIC COST — CENTS / KWH 28 30 32 34 36 38 40 EXHIBIT 17 ECONOMIC COST — CENTS / KWH REGIONAL ENERGY REQUIREMENT SUPPLIED MWh x 103 ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT ANNUAL ECONOMIC COST OF FIRM ENERGY :-HARZA ENGINEERING COMPANY EXHIBIT 18 Other Relative Brown Pink Chum Red Coho: Rainbow Sport Cost of Moose Bear Caribou Raptors Salmon Salmon Salmon Salmon Trout Pish Recreation Aesthetics Mitigation Chikuminuk Lake 7 2 z 1 2 = 3 1 - 3 and Allen River Kisaralik River 1 1 1 3 - 1 . 2 2 ed (Lower Falls) Kisaralik River 2 2 2 3 - 1 i. 2 1 3 (Golden Gate Falls) Kisaralik River 1 | 1 2 = 1 1 2 z 3 (Upper Falls) Kipchuk River x 1 x 2 1 3 2 3 2 3 Upnuk Lake - 2 1 1 - - 3 2 - 3 Milk Creek - 1 1 1 = = = - = = ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT RELATIVE RESOURCE VALUES AND COSTS OF MITIGATION HARZA ENGINEERING COMPANY EXHIBIT 18 jo ‘ FAIRBANKS \ ‘ e | PROJECT LOCATION ANCHORAGE a < . os = a~ | p> ee = ee YN > SCALE IN MILES (1:63,360) | ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT LOCATION MAP | CHIKUMINUK LAKE HYDROELECTRIC PROJECT HARZA ENGINEERING COMPANY December 1982 | Ay Se Damsite <Q . $ wees 3 SS BRIDGE ~~ POWER TUNNEL ACCESS ROAD ¢. | WY i SURGE CHAMBER a --*: ' —— - TAILRACE TUNNEL \) ACCESS TUNNEL - i - { \ UNDERGROUND ~ POWERSTATION 650 7 199 ; CK SCALE 0 400 800 FEET ood 1” = 800° ROCKFILL DAM ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT NOTE: Basemap topography eniarged from USGS Quadrangle sheets 1:63,360 series. CONCEPTUAL PROJECT PLAN CHIKUMINUK LAKE HARZA ENGINEERING COMPANY SIGNIFICANT DATA CHIKUMINUK LAKE HYDROELECTRIC PROJECT * RESERVOIR Water Surface Elevation, ft. msl Maximum Surcharge Water Surface Maximum Water Surface Minimum Water Surface Tailwater Elevation, ft. msl Surface Area at Normal Max. El., acres Estimated Useable Storage, acre-feet Type of Regulation Seepage Control Cutoff Wall HYDROLOGY Drainage Area, sq. mi. Average Annual Runoff, cfs/mi2 Stream flow, Average Annual, cfs DAM Type Maximum Height, ft. above deepest excavation Crest Elevation, ft. msl Crest length, ft. Dam Volume, cy Outlet Facilities SPILLWAY Type Crest Elevation ft. msl Crest Width, ft. Design Discharge, cfs EXHIBIT 21 Page l of 2 618 610 600 515 27,900 _ 230,000 Seasonal None 348 4.11 1432 Roll-crete 45 622 235 5,225 One 3-ft dia- Meter ‘steel pipe with con- trol valves Ungated con- crete overflow 610 50 5,000 ro Exhibit 21 Page 2 of 2 SIGNIFICANT DATA CHIKUMINUK LAKE HYDROELECTRIC PROJECT : - WATER CONDUCTOR Type and size 14-ft diameter, tunnel, reduc- - ing to two 8-ft diameter, tun- nels Length, ft. 2480' @ 14 ft diameter . 200' @ 8-£t diameter DIVERSION WORKS Type and size 16-£t diameter | unlined tunnel Length, ft. 400 Design Discharge, cfs : 1,800 POWERSTATION Number of Units 2 Turbine Type Standardized ‘ horizontal Francis Maximum Gross Head, ft 95 Rated Net Head, ft . 91 Operating Speed, rpm . : 300 Generator Rating, kVA 5,100 TRANSMISSION LINES Type 138 kV, 3 phase line Length, mi 130 POWER AND ENERGY Installed Capacity, kW 9,500 Firm Annual Energy Generation, MWh 39,000 WATER SURFACE ELEVATION FEET 680 AREA— THOUSAND ACRES 25 20 15 g £ Ss 620 15 2 2.5 VOLUME — MILLION ACRES EXHIBIT 22 ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT RESERVOIR AREA VOLUME CURVE CHIKUMINUK LAKE HARZA ENGINEERING COMPANY December 1982 a 77-0" _ EXHIBIT 23 6204 Max. Res. EL “02 . EL 6/0 Spillway and stilling basin rT teal er guide Wall 7 Flow. ate . Eh 6 Min. Res. El. mag Concrete { a 4" precast panels eee el Elevation - Feet Sf riginal river bottom ES A DAM - OVERFLOW AND STILLING BASIN SECTION Scale 0 10 Feet 10" a'-0 EL 597.0 Max. Res. El. 6/8 Rollerete dam whe wo" earoe : Normal Res. £6102 section crest or @ E/. 610. : \ Min. Res. El. 600 B 1 tunnel Flow, 4" precast panels ~ DAM NON OVERFLOW SECTION Scale 0 10 Feet 770 Scale 0 #00 800 Feet [Esher Eee 1" =400' Except as noted ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT CHIKUMINUK LAKE HYDROELECTRIC PROJECT 9,500 KW DEVELOPMENT ~ GENERAL PLAN AND SECTIONS HARZA ENGINEERING COMPANY EXHIBIT 24 Surge cnamcer Hite Siar aes Peseta ett a Noobs ies igh —~ & Powerhouse we - 6 14° @ Power funce /Max TW. E/.518 Nor mal TW. E/ 5/5 Elevation - Feet Elevation 7. T if T ‘ T ‘ T t T ' T - Af 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 PROFILE ALONG € POWER TUNNEL Scale 0 100 Feet Liceedennal T3100" Surge chamber house Top of surge chamber El 630 é ie Original ground |i [fees : 660 eens cy fed of ston 2 6-0" dia. ~. See (t#) “Assumed rock line lined tunnel! XK steer penatock eN 8 f (typ) NNN (typ) NES Intake house ae e Rese See ae “6404 20 ton bridge crane Bulkhead gate. | cAssumed rock line < aN ache Rn ? in store: So as, Pe age sigs + s/ti9n [| __30-0"% shot Bol : POPE, 622 Butterfly “Sv Governor 620 | Max. Aes. El. my - = shit valve (+9) SNS (typ. y i ete ee 2 i ; es § Normal Res. E16 Anes L ne oo et + a ee = ccess road i. Min, Res. £1. 600. = a Neg 12'-6" dia. riser Grati £1. 520: 600 sel 5 x ing & i - “ (typ) — Roll up D u Trashrack storage slot. A b eguisment Gate and trashrack slot Tl ri % é door $80 Flow, t | 3 sf. $67 a : Personne! 3 ~- $e coor Reck trap Trashrack Transition section ree SECTION THRU SURGE CHAMBER deck E/ 620 ‘Generator, switchgear and control cubicles (typ) SECTION THRU POWER INTAKE POWERHOUSE PLAN $ Unit Generator [Turbine \ Ra le € take-off structures 1.509 eee ea Grating. [ft turbine E/ $1) | Bulkhead gate and rock line Se aa PACH = / trashrack slot (typ) Original 48'-0" _) Steel truss with al eae plfansition section, ground lina” / built up rooting \ k St Scale 0 20 40 Feet Ai are ee ¢ 8°0" dia Butterfly valve z £1560 LELSEE stee/ penstock Pe hotieena t= ¢ fn EL S67-~ 0) y\ =| BO Rock enchors (typ) ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT —broft tube gate heist Max, TW. EL 518 Normal T.W. EL 5/5 t 8'-0" dia. stee/ pensteck Draft tube gate slot 6-8 (Turbine and Generator not shown) HARZA ENGINEERING COMPANY December 1982 MONTHLY SEQUENCES OF FLOW ‘ . EXHIBIT 25 ALLEN RIVER AT CHIKUMINUK LAKE OUTLET (CFs) Year Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June 1954 1383 816 541 383 278 200 173 861 2552 55 1160 1436 890 620 462 383 357 713 2927 56 1562 830 462 305 200 173 200 698 4211 57 1248 707 549 305 200 200 278 1094 3266 58 1801 2165 1115 645 450 383 370 844 5056 59 . 1474 738 515 436 278 173 200 728 3423 60 2207 1169 669 500 319 212 42 1167 4203 61 1546 1298 908 666 541 357 278 1378 4014 62 1513 885 406 330 305 252 252 924 3938 63 1204 751 593 646 672 630 331 764 3567 64 1591 634 317 199 161 120 121 283 4129 65 1765 941 541 357 252 278 436 684 4796 66 2856 1223 646 357 278 252 226 360 2693 67 2580 1381 860 603 454 358 313 442 2793 68 1411 613 341 245 216 200 200 867 2727 69 834 507 406 327 252 226 226 906 5946 70 2843 2081 831 432 323 278 252 977 3804 71 1049 634 382 , 285 234 216 206 755 3541 72 1536 1032 626 433 308 225 208 487 3040 73 1605 1424 810 522 370 282 234 768 3599 74 1644 798 456 313 240 226 228 925 2943 75 1634 1032 547 375 306 269 266 823 3470 76 1862 1094 543 301 186 92 70 $05 | 2717 77 2825 1472 878 676 529 364 258 592 4720 78 1387 816 494 444 377 331 333 2804 3741 79 1417 1230 1005 707 445 °326 438 1651 4709 80 2993 2245 1064 572 535 487 487 1603 5124 1981 1796 1452 631 555 580 518 487 1666 4654 Mean 1740 1120 644 448 348 286 267 938 3746 os 1 Mean annual streamflow - 1,432 cfs _ ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT MONTHLY SEQUENCES OF FLOW ALLEN RIVER AT CHIKUMINUK LAKE OUTLET HARZA ENGINEERING COMPANY December 1982 PROPOSED ROUTE. OF 138kV LINE Neha = CHIKUMINUK LAKE HYDROELECTRIC PROJECT EXHIBIT 26 ee ‘ N E FAIRBANKS e \ BETHEL : - ANCHORAGE i Co o rN iS gs JUNEAU 9 VICINITY MAP 0 20 40 SCALE IN MILES (1:1,000,000) bn, ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT PROPOSED TRANSMISSION LINE ROUTE HARZA ENGINEERING COMPANY December 1982 ESTIMATE Project_ Hydroelectric Project Struciwre: Project Wore i Estimated! by, No. | 20 | tan on and Bish a eee eee aera cre gee ae ee | cee re frees ee 331 | Powerplant Structures and Inprovenents | | | 3.873 foo mee eer ee eee eleeaeeeetecoeeetee eerste Si ee erased ee oe 332 333 ieee 335 [Miscellaneous Powerplant Bquipment | | 59 og fie fee, ee ees we Net Se eee eee eee gestae ta fare) ue eiccea le =e iseeaes gece eray wetercet eee en ee ee See) eee gga ee seer ee eee eee 2 eae MMO ce cee sre sr ss ee eles eee] Re ere ee eect Weg ie ee epee nT | eimai ica cs eee ee Ear eget Cee met | | aa 50 boo HARZA ENGINEERING COMPANY CHICAGO, ILLINOIS. Chikuminuk Lake : Reservoirs, Dams, and Waterways Waterwheels, Turbines, and Generators Accessory Electrical Equipment Roads, Railroads, and Bridges Qvantity se a ame seek ce eee eee eee | 7; Subtotal Direct Cost Contingencies (25% of Subtotal Direct qd Total Direct Cost gineering : (17% of Direct Cost) 8 Total Construction Cost— : TotaisConstruction Cost excludes escalatio ama dotnet Aawine anmctrnctian pst) LANawst oY Date_ December, 1982 Page__1 of __7 Pages “Checked by. Amount | 30 boo 000 eee eget ESTIMATE HARZA ENGINEERING COMPANY ‘ EXHIBIT 28 CHICAGO, ILLINOIS ‘ Chikuminuk Lake Project Hydroelectric Project Date December, 1982 Page__2 of 7 Pag Structure__ Project Works Estimated by Checked by remy ; ITEM Quantity Unit Price | Amount - _ |" slso0] rt 331 | Powerplant Structures and Improvements | | | | care ofwater CT ts Ts 2a ‘al cme <2 __tack__1t_sa,sm_ev_|_ig.g}_oaa :3| Rokboits att | eso || a 4 pesnation beggin acum ae | aan | ee A j--S-—_tnoniaa feret _et eaa { lan Prefabricated Metal Boot | 7,979 sf_| packfill | ny | Bridge Crane Rails and Hoist Rail | | | 00; oon ESTIMATE HARZA ENGINEERING COMPANY EXHIBI T 28 CHICAGO, ILLINOIS Structure Project Works Estimated by______ Checked by. | cofferdam T5750 cy | 16.00] _| 92 Joo 26 | Slurry Wall | —— se | | 27 fem jz | stiingmasin | Concrete 570.00 487 [000 p29 [spit ESTIMATE HARZA ENGINEERING COMPANY EXHIBIT 28 CHICAGO, ILLINOIS Chikuminuk Lake Project Hydroelectric Project Dote December, 1982 Page 4 of 7 Pay Structure_ Project Works Estimated by Checked by. ren ITEM Quantity Unit Price Amount 32 ‘ 4 |__| 41 tL 4 ee 8 4801000 4) Backing 850 cy | zs] | alo = | Foundation Preparation ss s| 5,283 Sf | 2.65| | sal o00 .43| Concrete (Incl. Forms) |S 4430 cy _| 570.000 _ ai salar .44| Reinforcement steel =i 374,783 bs | 1,15| | aaal ooo “45 a Q #6 __tuetableated Yen eusaine __/_.gme_sf___ansan}__aata 00 47 T serstaral steel Gun sme iho Se Seed Gee Sats BY]. [.ag| HVAC and Plumbing and Architectural| ss | Ss | [treatment —“‘“‘wR Ss Clg 49|_____Intake Gates and appurtenances | ss | S| S| agi] Bulkhead ates | ts SL acl 4] —bulltead Gates Guides Bo 000 493 |__| 1451 o¢ sod ——Storace slot Guides | SET os 000 [tard oc - aS |_| _aafocn Diversion Tunnel 1 SS ee ee oC [| __ Portal Excavation-Rock ss“ “ss| «789 cy ~—sd|st9.00| i158) 000 see heme Be ac 19,130 Ibs | 1.15 = 000 fa oe bi ; EXHIBIT 28 ESTIMATE HARZA ENGINEERING COMPANY CHICAGO, ILLINOIS Chikuminuk Lake Project___ Hydroelectric Project Date December, 1982 Page__5. of 7 Page Project Works Estimated by. Checked d by Structure. ITEM Reservoirs, Dams, and Waterways (Continue pa Leese NAR TT ee TT 110 emt TUL TA CL | tmmel—itigh-ead | 17,752_cy_|250.00 | _4 [438 [000 jest gta aie fazn.co | te90 bao pa | mnel—High-Head | 4137 cy |e10.00 | 3351 Joo N= 81 ooo so eS te. 27] orn eon, egemee A Ce emma OI LECT Tac eI 7) Lae UT immense a) me eee ieee a hes ee pe EE |.72] Riser and tenk | 740 cy [500.00 | 70 Jv |.724 Free Standing tank | 142 cy [690.00 | | 98 lov Taga me 1.74] Sumy trench 50.2 cy 645.00 | 80 bana AT meee TAM | i9.00 | | 42 loo ag A a Concrete Plug 87_ CY 460.00 | 40 looo 92 Steel Pipe - 3' Dia. 41.7 1f |120-.00 | 5 loo 93 Concrete 15.8 CY 0.00 9 1000 94 | Valves and Controls ss LDV Subtotal rte UU 333 _|Water-wheels, Turbines, and eels Turbine, Governor, Intake Va and Generator—-Transportation and aaeneie 750 |000 MM sey ESTIMATE HARZA ENGINEERING COMPANY EXHIBIT 28 | CHICAGO; ILLINOIS Chikuminuk Lake Project__Hydroelectric Project : Date__ December, 1982 Page__6 of 7 Pag_ Structure__ Project Works Estimated by Checked by hem Ne ITEM ; Unit Price Amount. 334 ol Accessory Electrical Equipment D-C Switchgear and Batteries; Station ' Service = Preneforer? aa Cable, and ee ee ee [Gromaing Systems; Lighting nd {| S| Sid S| Sid | commmicatins, tts 520 foe eI 335 eo eee Renmtars elmer ft i “ll a ee Ee |___intake Bridge Crane | ts | 6 fo v2] Powerstation Bridge Grane | ts | 70 000 13] Draft Tube Gate Hoist | ts Td a lor V2 | Miacelteneoue Bauigeest [as ooo pt Pot Subtotat them 335 | ps9 loon, , | : . 336] Roads, Railroads, and Bridges _ lL Steel Bridge and River Crossing Ls : oor 352| Transmission Plant Structures and - Improvements (Switchyard and Substations) Concrete Foundations 3 Fence . 1,393 _1£ 28.00 39 {O0L- 4 Prefabricated Metal Building . 3,600 sf 105.00 378 j00r - Subtotal Item 352 682 |00N ey ESTIMATE HARZA ENGINEERING COMPANY EXHIBIT 26 CHICAGO, ILLINOIS Chikuminuk Lake Project___ Hydroelectric Project Date December, 1982 Page__7 ofa? Page Structure___ Project Works Estimated by_____-_ Checked by. No. L[ Sdtcnesr, treater ad edie [| |__| usc 0 0 eT ao Z| pecntving substation | es | fro Te = IE A BE Te TT TT ETL AE AS ee a a ee eg 00 ag oe a = A OA ES 5 expe TET OTT TT [ot | webitiaation at eebiieatien [ae ee TT TO | i | IN EXHIBIT 29 Page 1 of 3 SIGNIFICANT DATA CHIKUMINUK LAKE HYDROELECTRIC PROJECT SPACE HEAT ALTERNATIVE RESERVOIR Water Surface Elevation, ft. msl Maximum Surcharge Water Surface 666 Maximum Water Surface 660 Minimum Water Surface 640 Tailwater Elevation, ft. msl . 515 Surface Area at Normal Max. El., acres 34,250 Estimated Useable Storage, acre-feet 625,000 Type of Regulation Seasonal Seepage Control Cutoff Wall 4000 ft . : : slurry cut- off wall . with aver- age depth on of 40 feet HYDROLOGY Drainage Area, sq. mi. . 348 Average Annual Runoff, cfs/mi2 4.11 Stream flow, Average Annual, cfs 1432 DAM Type " Rock£ill . with imper- vious flex- ible men- brane Maximum Height, ft. above deepest excavation 86 Crest Elevation, ft. msl. 676 Crest length, ft. 590 Dam Volume, cy 142,940 Outlet Facilities One 3-ft dia- meter steel pipe with con- trol valves SIGNIFICANT DATA EXHIBIT 29 Page 2 of 3 CHIKUMINUK LAKE HYDROELECTRIC PROJECT SPACE HEAT ALTERNATIVE SPILLWAY Type Crest Elevation ft. msl Crest Width, ft. Design Discharge, cfs WATER CONDUCTOR Type and size Length, ft. DIVERSION WORKS Type and size Length, ft. Design Discharge, cfs POWERSTATION. Number of Units Turbine Type Maximum Gross Head Rated Net Head, ft Operating Speed Generator Rating, kVA by Ungated con- crete overflow 660 50 2900 18-ft diameter, concrete lined tunnel, reduc- ing to three 9 £t diameter tunnels 2250' @ 18 ft diameter 450' @9 ft diameter 20-ft diameter unlined tunnel 400 1800 2 Standarized horizontal Francis 145. 133 300 10,000 EXHIBIT 29 Page 3 of 3 _ SIGNIFICANT DATA CHIKUMINUK LAKE HYDROELECTRIC PROJECT SPACE HEAT ALTERNATIVE TRANSMISSION LINES Type . " 138 kv, 3 phase line Length, mi 130 POWER AND ENERGY Installed Capacity, kW 24,500 Firm Annual Energy Generation, MWh 113,500 Up er EXHIBIT 31, ,, Max. Res. El. 666 mat Res. El. 660 Original ground tine + Min. Res. E/.640 3 [ee ON Power intahe eT Seopa cheats 3 = wo / / een a _ ose ge er 700 § ws ae { Assumed rock line. : § cena = Sa Tae eee — -- —_ S600 meee 5 === -- icc ne peey aeons 600 8 2 2 s Baers S : ra 3 \18" 6 Power funnel 500 T a T 7 ral x T me T Tecnvaae], Tee r T a T a T J T r T : T F atk t 600 600 1000 1200 400 1600 1800 2000 2200 2400 2600 2800 4000 3200 4400 PROFILE ALONG € POWER TUNNEL Scale 0 100 Feet [evvsuveve) os aN as ON as End of stee! Ss ae (typ) €9 ‘0° dua steel» Mined enstock ms Ps rains RAN (typ) Ae N, RS rs 19 i Surge chanber het Noa Nae : house —~ . SORES 202'- 0" a = Intake house . [Tap ah saree SS x me 4 A x i riginal ground line, S SS 56-0" NOON B60" NN x 56-0" 34-0" Bulkhead gate in stored position dee ee Battertiy 680 EL 676, a A em * EMax WS. E1678 NS \ Senet Gener ater oN Max. Res. Ef 666 re * kee a — 66g] Normal Res. Ef wwe } ‘ 4 | P i ——e fF Assumed rock fine Trashrack storage slot — ‘ ~— ake se 5 te x x % 6404 Min. Res. £1 640 | inl é 4 f ' | y t S 620 Ss Assumed rock line Stott F 2 HE ; a oo On ee aise s { G coo. iN oat? tubeldock Generator, switchgsar &/.$20 ft and control cubicles (tw) S| | a —A— — sh Ne +t 580- Rock trap POWERHOUSE PLAN | Transition section, 560 x, | pp de a S Fh S EU 542 : SECTION THRU POWER INTAKE Saar (Erte & Unit =I Generator {Turbine : = : + = Floor El. 500 ~ | ¢& turbine Ef. $02 £950" dia stee/ penstock Bulkhead gate and trashrack s/ot (typ) nesemed ce © Hehe off strocéures « c-c¢ rock fine ScaleQ 20 40 Feet Transformer lok ad Original ary jE bower toane! ey ae pe on Steel truss with butt op rooting ee es {and intake EL 566 eed 26 E = 38 ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN Et. $43 ratt tube gate hoist Rock anchors) (typ) E1520 ee EN FEASIBILITY ASSESSMENT Transition section | oO de Normal TW. El, $15. Se ee ee ‘ rs . —— gtee/ pensfock ieee : \ Oratt tube gate slot HARZA ENGINEERING COMPANY December 1982 8-8 (Perstecn, Turbine and Generator not shown) rp General Category Biological Environmental Transmission line 17 After Lee 1978. EXHIBIT 32 Factor Supsected High Collision Risk Situations Species Nocturnal fliers or those with awkward flight characteristics Age Immature birds with limited flight experience Health Sick or injured birds Migration Migrants as opposed to residents birds Sex Birds involved in nuptial displays Flight intensity Altitude of flights Size of flocks Time of flights Weather Habitat Human activity Geographical location Tower type Voltage Conductor charac. No. of lines Overhead groundwire Line length Age of line Aircraft warning light Large numbers of birds crossing the right-of-way during all times of day Altitudes equal to or lower than the uppermost wires Large flocks with small spacing between birds Nocturnal flights and diurnal flights during inclement weather Fog, snow, rain, sleet, or high winds Attractive bird habitat on and surrounding the right-of-way Hunting and other human activities which startle or distract birds Lines lcoated perpendicular to a narrow, low-altitude flyway Guyed structures or tall towers near river crossings Lower voltage lines with reduced electric field and corona effects Small diameter, single conductor/phase configurations Double-circuit lines with wire at different heights Multiple wires small in diameter compared with conductors A long line through a high use area A newly constructed line before birds can habituate Nonflashing lights on towers in established flyways ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT FACTORS WHICH MAY INFLUENCE AVIAN COLLISION RATES WITH OVERHEAD WIRES HARZA ENGINEERING COMPANY December 1982