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Home My WebLink AboutAPA1291I I I I I I I I I I I I I I I I I I J / . _./~BZ~~Uf. Jililli~,~ ~2f~~4 .• .,->• ·~'"7 ~ r·----------------------- 1 I I I I I i I I l I I I ! Prepan:~o by~ i . ~~I~ SUS!TNA HYIJROELECl'RIC PROJECT FEASIBILITY HEPORT VOLU~lE ; FIRST DRAFT SECTl :)N.~ i-8 l I I I I I i I I I I I l i I • I I I r • I I I ' I ·•·. • .-,._, ·-<"~ ...... ~ ...... ~· · ALASKA .PC\~ER· AUTHORITY . SUSITNA HYDROELECTRIC PROJECT TRANSM·ITTAL DATA SHEET TASK NO._. --~6~---- SUBTASK NO.----- TITLE Feasibility Report, Velum~ 1 Sections 1-8 PREPARED BY Mac Vanderburgh DATE OF ISSUE . February 3~ 1982 FILE NO. P5700.07.06 STATUS CIRCULATION X FIRST DRAFT SEE ATTACHED PAGE FINAL DRAFT ' APPROVED BY ACRES . . INSTRUCTIONS. X REVIEW· AND COMMENT BY (DATE) February 15, 1982 CIRCULATE AS SHOWN . RETURN TO BY {DATE) . X . RETAIN COPY NO. 8 [i]· DOCUMENT DISTRIBUTION RECORD .,. 1 of 1 Mac Vanderburgh ( Engineer Co-ordinator Typist Co-ordinator . Report Type of Document Number of copies bound __ 2_1 __ Distributed to Address A 1 as~ta Power Authority _ Name of Client Feasibility Report, Volume 1, Sections 1-8 'Mtfe of Document P5700.07.06 February 1982 Ch1191 Number Month Yw Number Distributed Alaska Power Authority Anchorage, AK 99501 (copy 1 thru 5) 5 . Jim Gill .... Acres American, Anchorage Office 6 & 7 2 t-Jofi~ o. Lawrence II it Buffalo Office 8 1 ' J. W. Hayden/R. L. Lietrick II II II II 9 1 , D. c. Willett (File Copy) 11 II II II 10 1 ' Gavin Warnock· (for·dist.*) II II Toronto Office 11 1 ' P. Hoover/C. Debelius II II Columbia Office 14 1 ' M. R. Vanderburgh II II Buffalo Office 12 1 ' J. E. McBee II II II It 13 i , D. ~~. Lamb II II II II 15 1 , . M. Grubb/K .. Young u u II II 16 1 ' R. Ibbottson II II u II 17 1 ' G. Krishnan/M. Dumont II II II II 18 1 ' v. Singfi/S. N. Thompson II II II II 19 1 ' M. Green (proof) II II II II 20 1 ' Susitna File Copy II II II II 21 1 ' Total Distributad 21 Fur eech document• that you co-on:hnate, complste the distribution .sheet in triplicate; attach a copy of the document to it;. distdbute at foUows: · First copy -Central Files Second copy -Engineer Co-ordinator Third copy -Secretarial Supervisor • for diltribut•an of Pf'OPOIIII. refw to Sec:reta-i-' ·~ Fonft 21SA ... ~ . .~ I I I I I . . . •••• I I I I I I 1: I- I I I I ALASKA POWER AUTHORITY SUSITNA HYDROELECTRIC PROJECT FEASIBILITY REPORT VOLUME 1 -ENGINEERING AND ECONOMIC ASPECTS FIRST DRAFT FEBRUARY) 1982 I I I I I I I I I I I I I I I I, I I I SUSITNA HYDROELE.CTRIC PROJECT FEASIBILITY REPORT PRELIMINARY OUTLINE VOLUME 1 -ENGINEERING AND ECONOMIC ASPECTS " "- Paqe 1 -INTRODUCTION ••o•·,··-········-····-·········,..·-··-t.:· .. ········"'·-··~····· 1-1 1.1 -The Study Area ................. ~ ............ , . .. . . . . . . . . . . .. 1-1 1.2 -Project Description ····················~a··············· 1-2 1.3 -Objectives and Scope of Current Studies ~················ 1-3 1.4 -Plan Formulation and Selection Process ..••.••• ,. ••.....••. 1-4 1.5 -Organization of Report . . • . .. . • • • . . • . . . • . . . • . • • • .. . . . . . . • . . 1-6 2 ·-S UMfvJAR Y • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • t; • • • • • • • • • 2 .1 -Scope of WOrk ....................... ~ .................. . 2.2 -Previous Studies .•...•...••.••.......•.••.•...••.....•.. 2.3 -Railbelt Load Forecasts ................................. . 2.4 -Rai lbeit System and Future Power Generating Options •.••. 2.5 -Susitna Basin •.•.••....•••.•....•• ~ ...•..•....••.....•.. 2.6 -Susitna Basin Development Selection ..•..•...•••••.•.•... 2.7 -Susitna Hydroelectric Development ••.....•.•.....•.....•. 2.8 -Watana Development .......•...•..•.. ¥ •••••••• ~ •••••• ". "" ••• 2.9 -Devi 1 Canyon Development . ~ .............................. . 2.10-Transmission Facilities ................................ . 2.11 -Estimates of" Cost •••.......•...•........ ~ •....•.....••.. 2.12-Development Schedule ······················j············· 2.13-Environmental Impacts and Mitigation Measures .••...••.•. 2,,1"4 -Project Operation ...••..•..•....•...•••.•••••.••...•.•.••. 2~15-Economic and Financial Evaluation ...•..•..•.•••••.••...• 2.16 -Conclusions and Recommendations . ~ •.•••.••.•...•.•...•.•. 3 -SCOPE OF WORK ··~······················Q························ 3-1 3.1 -·Evolution of Plan of Study . . . . • • • • . . . . . . • . . . . • . . • . . . . . .. • 3-1 3.2 -Task 1: Power Studies ............................... ., •. 3-3 3.3 -Task 2: Surveys and Site Facilities ..................... 3-4 3.4 -Task 3: Hydrology ···········•··········~·········&~···· 3-6 3.5 -Task 4: Seismic Studies •.•.....••.•.•.••..... ~ •...••.•. 3-7 3.6 -Task 5: Geotechnical Explorations •..••......•.••..• ~... 3-8 3.7 -Task 6: Design Development .•.•.••..•.•..•••.• .-•••....•• 3-10 3. 8 -Task 7: Environmental Studies ..• , • . . . . . . • • • • . • . . .. • • . . . . 3-11 3. 9 -Task 8: Tr ansmi ssi on • • . . • • . . . . • • • • • . . . . . . • • • . • . . . • . . .. . 3-12 3.10 _. Task 9: Construction Cost Estimates and Schedules .. • . . • • 3-14 3.11-Task 10: Licensing···················~·········~········ 3-14 3.12-Task 11: Marketing and Financing •••.••.•..•..•....•.•••• 3-16 3.13 -Task 12: Pub 1 i c Part i ci pat ion Program ...•..•....••.• : . . . 3-17 4 -p·REVIOUS STUDIES ............ -.·o; ••••••••••••••.•• ·······-~~··········· 4--1 4.1 -Early Studies of Hydroelectric Potential •.••••••.••••••• 4-1 4.2 -U.S. Bureau of Reclamation -1953 Study . • • • • • • • . . • • • • • • . 4-1 4.3 -U.S. Bureau of Reclamation-1961 Study ..... ., ............ 4-2 4.4 .-Alaska Power Administration-1974 ••.•..•. n••··········· 4-2 4.5 -Kaiser Proposal fm" Development ........................... 4:..2 4.6 U.S .. Army Corps of Engineer -1975 and 1979 Studi-es ...... .., .-., ......................... ~.. ........ . . . .. ..... .. . . .. 4 ... 3 I •• I I I I I I I I I I I I I I I I I. VOLUME 1 -ENGINEERING AND ECONOMIC ASPECTS (Cont~d) ' . ' -. . ' Page 5 -RAILBELT LOAD FORECAST································~········ 5-l 5.1 -Scope of Studies .•.... ····~····························· 5-l 5.2 -Electricity Demand Profiles ·······~······••H•··· ... ~ .. ·· 5-l 5.3 -ISER Electricity Consumption Forecasts . . . . . • • . . • . .... ... •. 5-2 5.4 -Past Projections of Railbelt Electricity Demand ..•.....• 5-7 5.5 -.Demand Forecasts ···········o···························· 5-7 5.6 -Potential for Load Management and Energy Cons.erva.tion .............................. ~ ............ ,.... 5-8 5.7 -Load Forecasts Used for Development Selection Studies . . . 5-9 5.3 -Battelle Load Forecasts . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . 5-12 6 -RAILBELT SYSTEM AND FUTURE POWER GENERATION OPTIONS ...........• 6.1 -Basis of Study ......... ~ ....•.....••.........•..•.....•. 6.2 -Existing System Characteristics ............ H ~ ••••••••••••• 6.3 -Fairbanks -Anchorage Intertie .......................... . 6 .. 4 -Hydroelectric Options .......••.......................... 6.5 -Thermal Options -Development Selection ................. . 6.6 -Thermal Options-Economic Analysis ...........•......... 6.7 -Without Susitna Plan·················~·················· 7 -SUSITNA BASIN ....... ·til .................................. o ••••••.••••• 7.1 -Climatology .......................... ~ .· .................. 't'". 7 . 2 - H yd r o 1 o g y • • . " . . . . '0 .,. ~ • • • • • • • • • • • • • ~ • • • • • • • • .• • • • • • • • • • • • • • 7.3 -Regional Geology ···································i·~·· 7.4 -Sei·smicity ··············~·················~·•:t:~:: ... •=····-:······ 7.5 -Water Use·& Quality ....................................• 7 .6 -·Fisheries Resources ...................................... . 7.7 -Wildlife Resources ··········~··························· 7.8 -Botanical Resources·································$··· 7.9 -Historical and Archaelogical Resources ................•. 7.10-Socioeconomics ·························a•·········4····· 7.11-Recreational Resources ....•...••........................ 7.12-Aesthetic Resources ·································o··· 7.13 -Land Use ................................................ . 8 -SUSITNA BASIN DEVELOPMENT SELECTION ............................ . 8.1 -Plan Formulatiori and Selection Methodology············~· 8.2 -Damsite Selection ·······························~······· 8 3 S•t ~-~ .. -1 e ._,)\,.. reenl ng ...... ~ .......... 0 .& .......... 0 .............. e •• 8.4 -Engineering Layouts ...................... ~ . ,. ....•....... 8. 5 .... Cap i t a 1 Cost. . ... 1:< ............................... , •••••••••••• 8.6 -Formulation of Susitna Basin Development Plans ....•..... 8.7 -Evaluation of Basin Development Plans ...............••.. 8.8 -On-line Schedule··········~~····················~······· 6-1 6-l 6-2 6-3 6-4 6-7 6-11 6-12 7-1 7-1 7·-3 7-7 7-8 7-17 7-18 7-19 7-23 7-24 7-24 7-26 7-26 7-27 8-1 8-1 8-2 8-3 8-5 8-10 8-11 8-13 8-23 lc· I ~ I List of Plates I Plate Title 1 RaiTbelt Area I 2 Devil Canyon Hyd~o Development Fill Dam I 3 Watana Hydro Development I Fill Dam 4 Watana I Stages Fill Dam 5 High Devil Canyon I Hydro Development 6 Susitna III Hydro Development I 7 Vee Hydro Development I 8 Denali & Maclaren Hydro Developments I 9 Preferred Tunnel Scheme 3 Plan View I 10 Preferred Tunnel Scheme 3 I Sections 11 Watana Arch Dam Alternative I 12 Watana Alt~rnative Dam Axes I 13 Watana Preliminary Scheme~ I 1.4 Watana Scheme WPl Plan 15 Watana Scheme WP3 Sections I List of Plates (cont'd) I Plate Titlt.~ 16 Watana I Schemes WP2 & WP3 Pl ctn and Section I 17 Watana Scheme VJP2 Sections I 18 Watana Scheme WP4 Plan I 19 Watana Scheme WP4 I Sections 20 Watana Scheme WP3A I 21 Watana .. Scheme WP4A I 22 Watana Simulated Reservoir Operation I 22A Devil .canyon Simulated Reservoir Operation I 23 Gevil Canyon Scheme DCl I 24 Devil Canyon Scheme DC2 I 25 Devil Canyon Scheme DC3 26 Devil Canyon I Scheme DC4 27 Devil Canyon I Selected Scheme 28 Alternative Access Corridors I 29 Alternative Access Routes 30 . Access Plan I Recommended Route I I .I •• I I I I I I I I· I I I I I I .I I I Plate 31 32 32A 33 34 35 36 37 38 39 40 41 42 ··43 List of Plates (cont'd) Title Watana Reservoir Plan Watana Site Layout Watana General Arrangment Layout of Structures Plan Watana Hydrological Data Sheet 1 Watana Hydl"O 1 ogi ca 1 Data Sheet 2 Watana Genera 1 Layout Site Facilitie.s Watana Village and Townsite Watana Main Construction Camp Site Watana and Devil Canyon Construction Camp Details Watana Diversion General Arrangement Watana Diversion Scheme Sections Watana Diversion Intake Structures Watana Downstream Portals Plan and Section Watana Emergency Release Sections I I I I I I I I I I I I I I I I I I I Plate 44 ' 45 46 47 48 49 50 51 52 53 54 55 List of Plates (cont•d) Title Watana Main Dam Plan Watana Main Dam Sections Watana Main Dam Grouting and Drainage Watana Outlet Facilities Gate Structure Watana Outlet Facilities General Arrangement Watana Main Spillway General Arrangement Plan and Profile Watana Main Spillway Control Structure Watana Main Spillway Chute Sections Watana Main Spillway Flip Bucket Discharge Structure Watana Emergency Spillway Watana Power Facilities General Arrangement Watana Power Facil i'ties Plan and Sections I List of Plates (cant' ti} · 1. I Plate Title I 55 A Watana Power Facilities Plan, Sections and Elevations I 56 Watana Power facilities Access I 57 Watana Powerhouse I Plans 58 Watana Powerhouse I Sections 59 Watana I Transformer Gallery Plan and Sections I 60 Electrical Legend 60A Watana I Powerhouse Single Line Diagram 61 Watana Switchyard I Single Line Diagram 62 Block Schematic I Computer-Aided Control System 63 Devil Canyon Reservoir I Plan 64 Devil Canyon I Site Layout 64A Devil Canyon I G~neral Arrangement Layout of Structures I 65 Devil Canyon Hydrologic Data Sheet 1 I 66 Devil Canyon Hydrologic Data Sheet 2 I I I List of Plates (cont•n) I ·Plate Title 66A Devil Canyon I General Layout Site Facilities I 67 Devil Canyon Temporary Village I 68 Devil Canyon Construction Camp Plan I 69 Devil Canyon Diversion General Arrangements I 70 Devil Canyon Diversion I Sections 71 Devil Canyon I Dams Plan and Profile 72 Devil Canyon I Main Dam Geometry I 73 . Devil Canyon Main Dam Geometry I Crown Section 74 Devil Canyon Main Dam I Thrust Blocks 75 Devil Canyon I Main Dam Grouting and Drainage I 76 Devil Canyon Saddle Dam General Arrangement Sections I 76A Devil Canyon Outlet Facilities I \ 77 Devil Canyon Main Spillway I Genera 1 Arrangement., Plan and Profile I I I I I ~I I I I I I I I I I 01 I I I I Plate 78 79 80* 81 82 83 84 85 86 87 . 87A 88 89 *Not Included List of Plates (contJd) Title Devil Canyon Main Spillway Control Structure Devil Canyon Main Spi1lway Chute Devil Canyon Main Spillway Flip Bucket · Devil Canyon Emergency Spillway General Arrangement De vi 1 Canyon Emergency Spillway Sections Devil Canyon Power Intake Structures Plan and Sections Devil Canyon Power Facilities Devil Canyon Powerhouse Plans Devil Canyon Pov1erhouse Plan and Sections Devil Canyon Powerhouse Sections Devil Canyon Transformer Ga 11 ery General Arrangement Plan and Sections Devil Canyon Powerhouse Single Line Diagram Devil Canyon Switchyard Single Line Diagram I I I· I I I I I I •• I I ., I I I I I I Plate 90 91 List of Plates (cont 'dJ . Title Watana Construction Schedule Devil Canyon Construction Schedule · I I I I I I I I I I I I I I I I I I I l -INTRODUCTION This Feasibility Report has been prepared by Acres American Incorporated (Acres) for the Alaska Power Authority (APA) under the terms of an Agreement, dated December 19, 1979, to conduct a feasibllity study and prepare a license applica- tiop to the Federal Energy Regulatory Commission (FERC). . · " The feasibi lfty study was undertaken in accordance with the Plan of Study (POS} for the Susitna Hydroelectric Project, which was first issued by APA for public review and comment on February 4, 1980. :.Thr~~e revisions to the POS were issued in September,. 198Q, December, 1981, and January, 1982 to take account of pub 1 i c, federal, and state agency comments anQ concel'·ns. The POS describes in detai 1 the many and complex studies to be undertaken from January, 1980 through June!) 1982 to assess the feasibility and the environmental impact of the proposed Susitna Project" The PQS also addresses the requirements for filing a FERC license application, which is currentlyscheduled for September 30, 1982. The filing of the FERC license application is cantingent upon acceptance of the findings of this report in terms of project feasibility and environmental acceptabi 1 i ty by the state, and a deci s1 on to proceed with construction of the development. · Studies by Acres through March, 1981 were mainly concerned with evaluation of the need for electric power in the Alaska Railbelt Region and preliminary consideration of the alternatives for meeting these power needs both with and without a Susitna Basin hydroelectric development. This work was undertaken in parallel with Rai lbelt power demand fot'"ecasting studies undertaken by the Institute for Soci a1 and Economic Research ( ISER) for the State of Alaska. The results of these studies were presented in June, 1981, in a Development Selection Report which described these initial steps in the POS process and provided recommendations and justification for continuation of study of basl:n development at two sites, Watan a and De vi 1 Canyon. Subsequent to selection of this basin development plan, engineering studies were continued to develop preliminary design and cost information for the Hatana and Devil Canyon sites. These design development studies were performed concurrent ... ly with ongoing site surveys and investigations, and environmental studies were updated in conjunction with an independent study of alternatives for meeting project Railbelt electric power requirements by Battelle Pacific Northwest, and also for the State of Alaska. All of this information was used to establish definitive project arrangements for t~atana and Devil Canyon as well as for the associated transmission facilities, to develop estimates of construction and operating costs, to undertake an economic and financial evaluatio·n for the Susitna Hydroelectr1c.Project, and to assess the environmental impact of the project and appro pi ate mitigation measures.. The remainder of this section <tea 1 s with a description of the study area and the proposed Susitna development and a summary of the objectives and scope of the current studies. 1.1 "" The Study Area - ihe main stream of the Susitna River originates about 90 miles south of Fairbanks where melting glaciers contribute much of its summer flow. 1-1 Meanderjng for the first 50 miles in a southerly d-irection across a broad allu- vial fan and plateau, the river turns westward and begins a 75 mile plunge be- tween essentially continuous canyon walls before it changes course to the south- west and flows for another 125 miles in a broad lowland to Cook Inlet, about 30 miles west of Anchorage .. The vast hydroelectric potential of this river ha~ been recognized and studied for more than 30 years. Strategically located in the heart of the South Central Railbe1t, the Susitna Basin could be harnessed to produce about twice as much electrical energy per year as is now being consumed in the Rai1belt region. The general locati'on of the Susitna Basin within the Railbelt area is shown on Plate 1. The Susitna River system, with a drainage area of more than 19j000 square miles, is the sixth largest in Alaska. Major tributaries include the Yentna, Chulitna, Talkeetna~ and Tyone rivers~ A substantial port ion of the total annual stream- flow occurs during spring and summer and· is generated by glacial melt and rain- fall runoff. The water during this period is turbid. Winter flows consist al- most entirely of ground water supply and are generally free of sediment~ Freez- ing starts in October in the upper reaches of tne basin; by late November, ice covers have formed on all but the most rapidly flowing stretches of the river. Breakup generally occurs during early May. - The Susitna River and its tributaries are important components of Alaska•s highly prolific fishery resource. Salmon, Dolly Varden trout, graylingj and whitefish are found within the Basin. Waterfowl habitat· in the· glacial outwash plain supports trumpeter swan and migratory fowl. Bear, moose, and caribou thrive there. Extensive studies are necessary to determine the tota1 value of these extensive wildlife resources, the impacts which any development may have upon them, and the nature of mitigative measures which might be taken to elim- inate or offset negative environmental consequences of hydroelectric develop- ment. · 1.2 ~ Project Description The Susitna Basin has been under study since the mid 1940s by agencies such as the U.S .. Bureau of Reclamation (USBR), the Alaska Power Administration, and tbe US Army Corps of Engineers (COE), as well as H.H. Kaiser and Company. The more recent and most compr~hensive of these studies was carried out by the COE. The optimum method of developing the hydroelectric potential of the basin was deter- mi_ned by the COE to comprise two major developments.. The first of these would require a ddm at the Watana site at approximately mile 183 of the Susitna River, and the second, a dam at the Devil Canyon site, approximately 31 miles dovm- stream of Watana. The locations of these sites are shown on Plate 1. This development was found to be economically viable and would provide the Railbelt area with a long-term supply of relatively cheap and reliable energy. Development selection studies completed by Acres in 1981 confirmed that the pre- ferred Susitna development plan should consist of two 1 arge hydroelectric dams at Watana and Devil Canyon. The Development Selection Report recommended fur- ther study of hydroelectric installations at these two sites. The preliminary studies indicated that an earthfi11 dam, roughly 880 feet maximum height, would be constructed at Wat ana first.. The 1 arge reserve ir volume created would I I ,I I I I I I ~a I ~· I I I I I I I I I I I I I I I I I I I I I I I I provide adequate storage-for seasonal regulation of the flow •. Initially, approximately 400 MW of generating capacity would be installed at this site. This would later be expanded to around 800 MW to allow for additional peaking capacity. The Devil Canyon dam would be· the next stage of the development. It would involve a 675-foot maximum height double curvature concrete arch dam and incorporate a 400 MW powerhouse. The total average annual energy yield from this development was estimated as 6200 GWh. The Watana and Oevi 1 Canyon developments together comprise the Susitna Hydroelectric Project. Design studies-undertaken subsequent to the selection of the Susitna develop- ment plan confirmed that the optimum installed generating capacity for Watana should ultimately be 1020 MW, and that first power should be available in 1993. Oevi 1 Canyon would add 60Q MW to the system by 2002. The most suitable access route to the site would involve a road from the Parks Highway west to Gold Creek, then along the south· side· of the Susitna River to Devil Canyon and along the north side of the river to Watana. The power from each of the two sites would be conveyed by double 345 kV transmission lines to the proposed Anchorage-Fairbanks intertie at Gold Creek. The connection to Fairbanks would finally consist of double 345 kV lines, and to Anchorage triple 345· kV lines vi a a cable crossing at Knik Arm near Point Mackenzie. The economic evaluation confirmed that the project would have a favorable benefit-cost relationship over a range of probable economic and financial conditions, and that the necessary financing and power marketing arrangements were feasible. 1.3 -Objectives and Sco_Ee of Current Studies The assessment of feasibility of an undertaking as important and as significant as the proposed Susi tna Hydroelectric Project rBqui red an appropriately high level of effort in terms of field and office activities. Three primary objectives were first identified: -To establish technical, economic and financial feasibility of the Susitna Project to meet future power needs of the Rai lbel t Region of the State of Alaska; -To e~;aluate the environmental consequences of designing and constructing the Susitna Project; and -To file a completed license application with the Federal Energy Regulatory Commission. The. scope ~f work was carefully structured to meet these objectives in the availab'le time frame in a manner appropriate to the scale, variety, and complex- ity of the problems involved. The POS was originally prepared and revised three times to address in almost exhaustive detai 1 the numerous work tasks and the many engineering, scientific, administrative, and associated supporting skills required. 1-3. A total of twelve major areas of study or tasks were identified: -Task 1: -Task 2: -Task 3: -Task 4: -Task 5: -Task 6: -Task 7: -Task 8: .., Task 9: -Task 10: -Task 11: -Task 12: Power Studies Surveys and Site Fac i1 it i es Hydrology Seismic Studies Geotechnical Exploratio~ Design Development Environmental Studies Transmission Construction Cost Estimates and Schedules Licensing Marketing and Financing Public Participation Program Two further tasks, 00 (Project Management) and 13 (Administration) were also established. These tasks were originally further subdivided into a total of 150 subtasks, ranging from five to 31 subtasks on a task-by-task bas is. R·evis- ions to the POS resolved in an additional 10 subtasks~ the largest task then accounting for 39 subtasks. Activities ranged from engineering and scientific data acquistions, literature review, research, dam studies, design computations and analysis, to field sur- veys, hydrau1 ic measurements, seismologic observations, geologic mapp_ing, geo- technical exploration, environmental data gathering, and the necessary logisti- cal support services. The study directly involved up to as many as 300 partici- pants at one time and drew upon a broad cross-section of contributions from expert specialists to the ordinary person. 1.4 -Plan Formulation Selection Process A key element in the studies undertaken was the process applied for formulation and comparison of. development plans. Emphasis was placed on consideration of every important perspective which could .influence the selection of a particular cour·se of action from a number of possible alternatives. An essential component of this planning process involved a generalized multi-objective deve1opment sE;l- ection methodology for guiding the planning decisions. A second important fac ... tor was the formulation of a cons is tent and rational approach to the economic analyses undertaken by the studies. (a) Planning Methodology A gener~ized plan formulation and selection process was developed to guide the various planning studies being conducted. Of numerous planning decis- ions made in these studies, perhaps the most important were the selection of the preferred Sus itna Bas in deve 1 opment plan (Task 6) and appropriate access and transmission line routes (Tasks 2 and 8). · The basic approach involved the identification of feasible candidates "' and courses of action:. fqll owed by the deve.1 opment and app 1 i cation of an appropriate screening process. In the screening process, less favorable 1-4 I :1 I I I I I 'I I I I I I I I I I I I· I I I I I I I I, I I I I I I I I J, candidates were eliminated on the basis of economic"' environmenta1 1 socia1:t and other prescribed criteria. Plans were then formulated which incorpor- ated the shortlisted candidatt:s individually or in appropriate combina- tions. Finally, a more detailed evaluation of the plans was carried outs again using .prescribed criteria and aimed at selecting the best development p1an. Figure l.lillustrates this general process. In the final evaluation, no attempt was made to quantify all the attributes used and to combine these into an overall numerical evaluation. Instead, the plans were compared utilizing both quantitative and qualitive attributes; where necessary, judgment a 1 tradeoffs between the two types were made="=at'ld highlighted. ··This a 11 ows reviewers of the p 1 anni ng process to quickly focus on the key tradeoffs that affect the decisions. To facilitate this procedure, a paired com\Jarison technique was used so that at any one step in the planning process, only two plans were being eva 1 uated. , (b) Economic Analyses Since the proposed Susitna development is a public or state pr.oject~ a11 p 1 anni ng studies described were carried out using economic parameters as a basis of evaluation .. This ensured that the resulting investment decisions maximized benefits to the state as a whole rather than any individual group or groups of residents. The economic analyses incorporated the following principles: -Intra-state transfer payments such as taxes and subsidies were excluded. -Opportunity values were used to establish the costs for coal, oil, and natural gas. resources used for power generation in the alternatives considered. These opportunity costs were based on what the open market is prepared to pay for these resources. They therefore reflect the true value of these resources to the state •. ·These analyses ignored the. existence of current term-contractual commitments which may exist, and which fix resource costs.at values different from the opportunity costs. -The analyses were conducted using 11 real" or i nfl ati on-adjusted para- meters. This means that the interest or discount rate used equaled the assessed market rate minus the general rate of inflation. Similarly~ the fuel and construction cost escalation rates were adjusted to reflect the · rate over or under the general inflation rate. -The major impact caused by the use of these inflation adjusted parameters. was the improvement of the relative e.conomics of capital intensive projects (such as hydro generation) versus the high fue] consumption · projects (such as thermal generation). It also le.d to the selection of larger economic optimum sizes of the capital intensive projects. These shifts toward the capital intensive projects were consistent with maxi- mizing total benefits to the state. 1-5 1~5 -Organization of Repor!_ The objective of this report is tn describe the studies undertaken to establish the feas1bility of the Susitna Hydroelectric Project. In order· to improve the continuity and c 1 ari fy the report, much of the detailed technical and environmental material is included in separate appendices. The report is organized as follows: Vo1 ume 1 ,-Engineering and Econofll.i£.1\Spects Section 1: Introduction A brief summary of the background of the Feasibility Report is presented in this section .. Sect ion 2: Summary This section contains a complete summary of Sections 4 through 19 of Volume 1. Section 3: Scope of Work ' This secti'on outlines the scope of work associated with the results of the Feasibility Study presented in this report. Section 4: Previous Studies A brief summary of previous Susitna Basin studies undertaken by others is given. in thi s section. Section 5: Railbelt Load Forecasts In this section, the results of the energy and 1oad forecast studies undertaken by ISER, Woodward-Clyde Consultants, and Battelle are summarized. It conc"ludes with a discussion of the range of 1 oad forecasts used in the Susi tna Basin planning studies: Section 6: Railbelt System and Future Power Generating Options This section describes currently feasible alternatives considered in this study for generating electrical energy to meet future Rai lbelt needsc It incorporates data on the performance and costs of the facilities. Section 7: Susitna Basin This section provides a description of the physical characteristics of the Susitna Basin including climatologic, hydrologi.c, geologic, seismic, and environmental aspects. 1-6 I I I ,I I I I 'I··. (': I I I I I I I I I I •• I I I I I I I I I I I I . ,~.· I .... .,___,. I I I I. r ,I ~~~Ch Section 8: Susitna Basin Development Selection Thi.s section outlines the engineering and planning studies undertaken for formulation of Susitna Basin Development Plans and selection of the preferred plan. The selected plan is compared to alternative methods of generating Railbelt energy needs on the basis of technical, economic, environmental and social considerations. Section 9: Selection ·af Watana General Arrangement Thissection describes the evolution of the general arrangement of the Watana Project. The site topography, geology, and seismicity of the Watana site is outlined relative to the desig·n and arrangement of the various site facilities. The process by which reservoir operatings levels and the installed ~1enerating capacity of the power facilities is presented, along with the selection of project design floods. Section 10: Selection of Devi 1 Canyon General Arrangement The development of the general arrangement of the Devi 1 Canyon Project is. described in this sectfon, in a manner similar to that outlined for Section 9. Section 11: Selection of Main Access Plan This section describes the process for selection of the main access plan, together with a discussion of the various economic, technical, environmental , and socioeconomic factors which influenced the. selected plan. Section 12: Watana Development · The various structures, permanent equipment, and systems which comprise the Watana Development are described in this section. Section 13: Devi 1 Canyon Development This section presents a description of the structures~ permanent equipments and systems which comprise the Devil Canyon Development. Section 14: Transmission Facilities The studies undertaken to select a power de 1i very system from the \~at ana and Devil Canyon Developments to the major load centers in Anchorage and Fairbanks are described in this section . Section 15: Project Operatfon This section describes the proposed operation of the Watana and Devil Canyon developments within the framework of the various requirements of energy demand and physical and environmental restraints. The dependable capacity and annual energy production for both developments are presented, together with a descrip- tion of operating and maintenance f aci 1 i ties and procedures and proposed perfor- mance monitoring of the various project structures. 1-7 Section 16: Estimates of Cost This section summarizes construction costs, mitigation costs, operating, maintenance and rep 1 acement costs, as we 11 as indirect costs such as engineering and -admi ni st·rati on costs, and a 11 owance for funds used during construct 1 on. Section 17: Development Schedule The schedule for planning, licensing, design, procurement, construction, and startup of the Watana and Devil Canyon Developments, together with transmission facilities, is presented. Section 18: Economic and Financial Evaluation This section presents the economic and financial evaluation for the Susitna Hydroelectric Projectt A discussion of power marketing options is also giv.en. / Section 19: Conclusions and Recommendations . This section presents the main conclusions of the feasibility study, toget1er with recommendations regarding further action which should be undertaken by APA. Volume 2 -Environmental Aspects This volume of the Feasibility Report·describes the environmental resources of the Upper Susitna Basin with specific emphasis on the proposed Watana and Devi 1 Canyon impoundment areas. Section 1 comparises a general description of the locale. Sections 2 through 9 contain detailed information on water use and quality; fish, wildlife, and botanical resources; historic and ~rchaeological resources; socioeconomic impacts; geolog-Ical and soil resources; recreational and aesthetic resources; and land use. This information is then utilized to- predict impacts of the construction and operation of the reservoirs, transmis- sion lines, and access road on the natural resources and socioeconomic condi- tions in the project area. In Section 10, _alternatives to the proposed project are discussed and evaluated from the environmental point of view. These alternatives include hydroelectric development within and outside the Upper Susitna Basin and thermal and tidal power development. A list of literature relative to the study is presented in Section 11. Vo 1 ume 3 -Pl ate·s 0 This volume contains all of the plates pertaining to the Feasibility Report .. Volume 4 -Electrical Supply and Demand Studies This volume contains the OGP data used to support and develop the electrical supply and demand studies. Volume 5 -Hydrological Studies This volume includes detailed hydrological and meteorolcgical data, supportive data for water resource studies and flood studies, ice studies, sediment yield and river morphology studies, climatic stud·les for transmission lines, and l.ower Susitna River studies. 1-8 ' I I I I I I I I ,, I I I I ...... I I I I I I I I I I I I I I I I I I I I I I I I Volume 6 -Project Land Studies This volume contains land status information, an inventory of private and public lands required for the project~ and marketability and disposal studies for the reservoir areas. Volume 7 -Design Development Studies This volume contains background and supporting data for dam selection studies, project layout studies, and power facilities selection studies. Volume 8 -Transmission Line Studies This volume includes electric systems studies, a report on transmission line cqrridor screening, and maps of the transmission line route. Volume 9 -Cost Estimates Detailed cost estimates and supporting cost data are presented in this volume. Volume 10 -Agency Consultation This volume contains a list of agencies contacted and copies of correspondence from agencies relative to the study. It also explains the programs developed to ensure agency input into p 1 anni ng and decision making associated with the project. · Volume 11 -Coordination and Public Partici.pation This volume describes the public participation program and presents a summary of public participation meetings conducted during the study program. 1-9 I I I I I I I I I I I I I I I I I I I LOCATION MAP ..LEGENQ \J' PROPoSED DAM SITES LOCATION MAP FIGURE 1.1 f -- DEFINE OBJECTIVES --·--------.. ·-·---- INPUT FROM AVAILABLE SOURCES· PR~VIOUS AND CURRENT STUDIES SELECT CANDIDATES SCREEN FEEDBACK FEEDBACK PLAN FORMULATION . AND SELECTION ME.THODOLOGY LEGEND ---'\ STEP NUMBER IN 4 STANDARD PROCESS (APPENDIX A ) FIGURE 1,2: lutal -----·- DEVELOPMENT OF ANt ALL THERMAL GENERATING PLAN DEVELOPMENT OF AN OTHER HYDRO G.ENERAT!NG PLAN _ .. DEVELOPMENT OF A SUSITNA BASIN GENERATING PlAN - ALL THERMAL PLAN OTHER HYDRO PLAN SUSITNA PLAN -· .. DEVELOPMENT OF THE BEST GENERATING SCENARIO LEGEND -- RECOMMENDED GENERATING SCENARIO - '\ APPLICATION OF PLAN L-.----v' ~~~~f~~~O~E~~&oLoGY 0 END PRODUCTS - PLANNING APPROACH 1.3 iil FIGURE I 2 -SUMMARY I -To Follow I I I I. I I ll 1 ---~~ I I I I I I I I 2-l I I I I I I I •• I I I I I I I I I I I I 3 -SCOPE OF WORK 3.1 -Evolution of Plan of Study The original Plan of Study (POS) for the Susitna Project Feasibility assessment was submitted by Acres on September 11, 1979 in response to the Request for Pro- posal issued on June 25, 1979, by Mr. Eric Yould, Executive Director of the Alaska Power Authority. Acres initiated study planning activities in accordance with the original POS under the terms of a contract with APA dated December 19, 1979. In response to suggestions from interested citizens as well as public and private organizations and agencies, a number of revisions were made to the original POS. A revised POS was issued for further public review an comment on February 4, 1980, prior to commencement of major portions of the work (1). Further revisions to the POS were subsequently issued September, 1980 (Revision 1,[2]), August, 1981 (Revis- ion 2, [3]) and January, 1982 (Reviston 3, [4]). · t a' ··~ POS Revisions . I The original Acres POS was prepared to include a wide range of comprehen- sive studies necessary to assess the technical and economic feasibility of- the" project and the environmental impacts which construction of such a pro- ject would cause. Details of the revised POS are presented in subsequent sections. Revisions which were made to respond to questions and concerns raised by reviewers included: To ensure objectivity in Railbelt electric load forecasting and genera- tion planning, the State of Alaska entered into separate contracts \"lith the Institute of Social and Economic Research (ISER) to develop inaepen- dent forecasts, and with Battelle Northwest to study alternatives for meeting future Railbelt electric energy requirements; -Significant increases in the amount of effort devoted to fisheries' and other environmental studies were introduced in response to comm~nt"s from the Alaska Department of Fish and Game and the U.S. Fish and Wildlife Service; -To ensure obj-ectivity in the conduct of the public participation program, it was decided that the public participation aspects of the study should be conducted under the direction of the Alaska Power Authority rather than by Acres; -The level of effort associated with marketing and finance studies \"las re- duced in the first phase of the study, thereby deferring certain financ- ing subtasks until initial questions as to project viability and concept had been-more thoroughly addressed; -Some changes were made in logistical and administrative support efforts both to accommodate the increased level of environmental activity and to ensure efficiency and responsiveness as the study progressed; and 3-1 (b) (c) -Additional effort was prescribed for in-stream flow studies downstream of Talkeetna in response to concerns expressed by the Alaska Department of Natural Resources. Basis of POS Prior to preparation of the Acres POS, numerous studies of the hydroelec- tric potential of the Susitna River Basin had culminated in a major pre- feasibility study by the U.S. Army Corps of Engineers which led to a recom- mendation in 1976 by the Chief of Engineers that the Susitna Project be authorized. The Corps plan recommended two high dams, the first of which would be built as a massive earthfill gravity structure 810 feet in height at the Watana site. The second Corps dam \'las to be a 635-foot-high thin arch concrete structure at the Devil Canyon gorge, more than 30 miles down- stream. By June 1978, the Corps of Engineers had prepared a plan of study describ- ing a program leading to completion of a detailed feasibility study for the project (5). Further investigations by the Corps confirmed the adequacy of the ~!atana site, though they did reveal that some design changes were re- quired. Data, analyses, and reports collected and prepared by the Corps of Engi- neers were used throughout the course of the work undertaken by Acres. The Acres ·pos comprised an initial series of tasks and subtasks, aimed at sel- ecting an appropriate concept for development, if development were found appropriate, by the end of the first year of study. This was followed by a more detailed series of tasks and subtasks to prepare and assess the feas- ibility of designs for each site development~ Specific Objectives of Study As a basis for structuring_the scope of work for the overall study, the· three primary objectives of feasibility assessment, environmental evalua- tion and preparation of FERC license were further subdivided into a series of more specific objectives, as fo1lows: -Determine the future electric power and energy needs of the south-central Railbelt area, based upon independent analysis by ISER; -Assess alternative means of meeting the load requirements of the Railbelt area, consistent with independent analyses by Battelle; -Prepare an optimal development plan for the Susitna Pr'oject wherein power costs and probable impacts are minimized, safety is enhanced~ and financ- ing is achievable; -Establish a definitive estimate of the total cost of bringing power on- 1 ine, together with a statement of cash flow requirements; -Evaluate the physical, economic, and financial risks of the Susitna Pro- ject and determine ways and means to avoid or minimize their conse- quences; I I I I I I I: I I I I I I I I I I I I "' , ... ~ .• ,. ->.Y~. ,· .... ·-"'"' ,,~ •• ,_,.~ ._,, .:.,.~· ........ ~. ~ ....... -7~· I I I I I I I I I I I I I I I I I I I -Evaluate existing environmental and social factors as they now exist in the proposed project area, assess the impacts of the proposed project, enhance environmental values to the extent possible, and recommend miti- gating measures; -Estimate the annual system power costs in the south-central Railbelt wit~ and without the project, study the integration of Susitna power into the Railbelt utility system, and assess power marketabi1ity; ·~ Subject to confirmation of feasibility and State authorization to pro- ceed, prepare a complete license application and file this with the Fed~ eral Energy Regula_tory Commission; -Ensure that the needs and des ires of the pub 1 ic are known, Keep inter- ested.parties and the public informed, and afford an opportunity for pub- lic participation in the study process; and -Determine an optimal program for achieving financing, including resolu- tion of issues regarding tax-exempt status of bonds which may later be offered. In formulating a logical approach to the study of a major hydroelectric development in a relatively hostile climate and environmentally sensitive region, it was necessary to identify the particular problems to be addres- sed and to· place these in proper perspective with the more routine elements of technical and economic feasibi1 ity assessment. To ensure an optimal development, it was essential to recognize and allow for all constraints imposed, and address such vital issues as environmental acceptability at the proper stage to all ow it to be considered adequately through pub 1 ic participation and other processes to satisfy licensing procedures. The financial viability of the project is also a vitally important considera-· tion which lies beyond the strict technical and economic parameters of the proposed development. The approach taken in the overall studies \"'as such that a confident determination of the financibility of the project could be accomp 1 ished. A summary of the activities undertaken in the twelve. major tasks is pre- sented in the following sections. 3.2 -Task 1: Power Studies As conceived in the February, 1980 issue of the POS, the objectives of this Task were essentially defined as the determination of the need for power in the south-central Alaska Railbelt region and the development of a technically:) eco- nomically and environmentally feasible plan to meet that need. Subsequent re- visions to the POS resulted in significant modifications to these objectives and the corresponding scope of work. (a) Demand Forecasts for Development Selection The derivation of forecasts of demand for electric energy in the Railbelt was based on work performed for the APA and the state in early 1980 by the 3-3 H' Institute for Social and Economic Research {ISER). Reviews of this work were the subject of a report issued in December, 1980 (6), which formed the basis of initial Susitna development selection studies. This report dealt with energy forecast~ alone.. The determination CJf the corresponding peak load forecasts appropriate for use in generation planning studies was the SJbject of further studies culminating in a second report also issued in December, 1980 (7). (b) POS Revision 1 As of June 6, 1980, following changes in State Legislation, all Task 1 work relating to study of Susitna alternatives by Acres was terminated, \vith the exception of the review of ISER work and derivation of peak load forecasts~ Revision 1< to the POS to formalize these scope revisions, was issued in September, 1980 {2). A final Task 1 Closeout Report to document there- sults of partially complete activities in studies of alternatives was issued in September, 1980 (8). As a result of these legislative changes, the State of Alaska selected Battelle Pacific Northwest Laboratories to undertake an independent study of alternatives for meeting future Railbelt region demand for electricity. The scope of the Battelle study includes an ~pdate of the ISER forecast for electric energy as well as an independent assessment of peak load. The incorporation of the results of these studies into Susitna planning studies in late 1981, is discussed under Task 6. 3.3 -Task 2: Surveys and Site Facilities The essential objective of Task 2 was to provide all necessary logistical sup- port and other related services for successful accomplishment of field activ- ities for completion of the feasibility studies and license application prepara- tion during the January, 1980 through June, 1982 period. Although the scope of this Task was expanded from time to time during the period of the study, the basic nature of the work did not significantly-change. These services included: -Procurement, erection, and continued operation of camps with associated per- mitting requirements; Appropriate pr·ovisions for surface and air transportation., communications, and fuel supplies; -Aerial, ground and hydrograph1c surveys; -Access roads studies; Reservoir area reconnaissance, slope stability, and erosion studies; and -Reservoir clearing and disposal studies. 3-4 I I I I I I I I I I I I I I I I I 'I I I I I I I I I I I I I I I I 11 I I I I (a) Fie 1 d Accommodation A 40-man camp supplied by Arctic Structures Inc. of 'Palmer, Alaska, was erected and placed in service by March, 1980. The camp building modules were designed in compliance with state ordinances and requirements for use in an arctic environment. The modules together with other equipment and materials necessary for camp construction were transported to the site by means of Catco Rolligon vehicles, in strict compliance with federal artd state permit restrictions, during the winter months when there was adequate snow cover on the ground. The camp comprised bedroom units and associated bathroom, kitchen/dining, recreation and fuel/materials storage facilities, and was used throughout the study period to house personnel engaged in numerous field activities. Self-contained water supply, electt:'ic power generation, sewage treatment, garbage disposal and he1 icopter 1 anding faci 1 ities completed the install a- t ion. During peak activity periods, particularly during the summer months, personnel were also accommodated ~t three local hunting lodges and in more remote tent camps. (b) Transportation Arrangements With the exception of initial surface transportation of camp modules and construction equipment and materials, all transpurtation of personnel and resupply of materials to the study area was accomplished by means of heli- copters and small fixed-wing aircraft~ Contractual arrangements were made at various times during the conduct of the study with five different com- panies for the supply and operation of helicopters and fixed-wing aircraft. These aircraft operated mainly from Anchorage and Talkeetna, the fixed-wing aircraft utilizing existing 1 andjng strips at those locations together with existing strips in the project area, lakes, and helicopter pads constructed at the camp and key working areas. . An effective system of radio and te·lephone communications was established to facilitate the operation of the aircraft and the camp itself. At peak periods, air transportation requirements for personnel traveling to numer- ous different locations on a daily basis, and for relocation of drilling and other heavy equipment, put a severe strain on logistical planning ef- forts. Particular attention was paid to safety and personnel security in all aircraft and helicopter operations. (c) Surveys Detailed topographic surveys were undertaken for the entire area of the project including reservoirs, damsites, access and transmission line corri- dors. Hydrographic surveys of important reaches of the Susitna River were also performed as a basis for Task 3 hydrologic and hydraulic design studies. These surveys were based on aerial photography and a comprehen- sive system of horizontal and vertical ground control which was established to complement USGS and Corps of Engineers mapping which already existed for parts of the project area. 3-5 I The bulk of the field survey work was undertaken during the first 18 months I of the study period. The processing and reduct ion of data for product ion of topographic maps was essent i al1y completed b_y, 1 ate 1981. The scheduling of field work and aerial photography \'faS made par-ticularly difficult by the I need to avoid periods of snow cover and tree foliage. Susitna River sur- veys were also hazardous, particularly at Oevi'l Canyon. Detailed results of the mapping were provided to the USGS for incorporation into their over-I all data base for the State of Alaska, and were used as a basis for design and feasibility assessment of the Susitna project. (d) Access Roads A comprehensive design and feasibility assessment of alternative access corridors-and routes was undertaken in Task 2. The objective of this study was to select an appropriate mode and route for access to the proposed Susitna development and a plan for implementation to meet the project sche, .• dule requirements. This work was undertaken in parallel with associated engineering, environmental, cost and scheduling studies in Tasks 6, 7, and 9. The final product of this study is a report entitled 11 Access Planning Studi' dated January, 1982 (9). (e) Reservoir Studies Reconnaissance of the Watana and Devil Canyon reservoir areas was under- taken first by means of aerial photography and overflying, and fina11y by on-the-ground inspection. The purpose of these studies was to identify areas of potential instability or susceptibility to erosion during filling and subsequent operation of the reservoirs. Basic information acquired during this phase of the study was used as input to Task 7, environmental studies of impacts of the reservoir impoundment. The information was also used as a basis for determination of requirements and costs for reservoir clearing and disposal of material?. A further activity undertaken during the course of the study was to identify the ownership and status of land in and adjoining the project and associated access and transmission cm·ridors. This· information was duly incorporated into the appropriate project planning and permitting processes. 3.4 -Task 3: Hydrology The original objective and scop0. of Task 3, as proposed in the February' 1980 POS, was to undert.ake all hydrologic, climatic, hydraulic and ice studies neces- sary to camp lete the feasibility assessment and designs for the Sus itna Project as a basis for the FERC license application. Under Revision 2 of the POS, which was issued in December, 1981, the scope of Task 3 was expanded to include addi- tional hydrologic and design studies in response to perceived public concerns. Work commenced in this Task early in 1980 with the inittation of data collection and man itoring and continued throughout the study period. Comprehensive results of Task 3 studies are presented in Appendix B to this report. 3-6 \' . . . . . ·. . . . . . . . . I I I I I I I I I I I I I I .I I I •• I I I I I I I I I I I I I I I I (a) Data Compilation A comprehensive network of climatic and hydrologic data collection systems with appropriate processing and distribution arrangements were established early in 1980 and operated for the duration of the study period. These. data provided a continuing basis of hydrologic and hydraulic studies and designs for assessment of project.feasibility and environmental impact. (b) Water Resources and Flood Studies These studies involved the processing of available and newly acquired cli- matic and hydrologic data for purposes of determination of streamflow availability for hydroelectric generation, reservoir operation simulations, and estimates of flood frequency and magnitude. These studies then formed the basis of project economic planning analysis and spillway designs under Task 6.. Under Revision 2 to the POS issued in December, 1981, in response to perceived public concerns, the scope of this activity was expanded. Additional activities included a re-evaluation of the probable maximum flood on the basis of more comprehensive data and the dam break analysis~ (c) Hydraulic and Ice Studies The scope of these studies included the determination of water levels and ice cover conditions upstream and downstream from the project sites for pre-and post-project conditions, making use of available and newly ac- quired hydrologic and hydrographic survey data. These studies were used as a basis for establishment of reservoir freeboard and operating constraints, and pre-and post-project water temperature and quality conditions as input to fisheries and related studies under Task 7. (d) Sedimentation and River Morphology These studies were undertaken to determine the rate of c;;ediment accumul a- tion in the proposed reservoirs and prediction of the effects of project operation in the downstream river channel morphology from Devil Canyon to below Talkeetna. Appropriate river sampling procedures were established during the sutdy period as a basis for these evaluations. (e) Transmission and Access Studies Climatic design criteria, including wind .velocity and ice accumulation estimates, were developed on the basis of available climatic data and ob- ~ervations for transmission line designs together with evaluation of design flood requirements for access road steam crossings. 3.5 Task 4: Seismic Studies This Task involved a wide range of field and office studies aimed at developing an understanding of the seismic setting and potential earthquake mechanisms of the region and determining the seismic design criteria for the structures to be built. The original February, 1980 POS for Task 4 included a two-year program of of activities for 1980 and 1981 to meet the study objectives. Some expansion 3-7 of field activities in 1981 was made under Revision 2 of the POS. (a) 1980 Studies The essential purpose of the 1980 studies was to install and operate a microseismic network in the project area and to idP.ntify, from historical and avail able remote sensing imagery data, potential tectonic features to be considered in establishing the seismic setting of the project. The 1980 studies also included a preliminary geologic reconnaissance, an assessment of rer~rvoir-induced seismicity, and preparation of a report (10). (b) 1981 Studies The 1981 studies involved a more detailed investigation and evaluation of a number of potential tectonic features identified in the 1980 studies. The work involved a large. degree of field mapping of quaternary geology in the project area and trenching of significant features. Revision 2 of.the POS increased the extent of the trenching work. Eva 1 uat ion efforts· inc 1 uded detailed studies of regional and similar worldwide earthquake characteris- tics, estimation of potential earthquake magnitudes and probability of oc- currence associated with important tectonic features, an assessment of the corresponding potential ground motions, and the development of appropriate earthquake design criteria for use in design of project structures. A manual was also prepared for installation and continued operation of~a permanent seismic monitoring system. ~ The results of the 1981 s~udies were incorporated into a comprehensive report (11) ~ 3.6 -Task 5: Geotechnical Exploration The objective of Task 5 as conceived in the February, 1980 POS was to determine the surface and subsurface geology and geotechnical conditions for the feasibil- ity studies of the proposed Susitna Hydroelectric Project, including the access roads and the transmission lines. This was accomplished by a comprehensive pro- gram of field exploration, geotechnical e.valuation, and dam studies over more than two years, commencing in early 1980. The scope of Task 5 was increased in 1982 in terms of _additional field work under Revision 2 to the POS, to respond to concerns raised by the Power Authority•s external review board. (a) Field Work Programs Programs of field work were developed and undertaken in summer and winter seasons in both 1980 and 1981, each of which culminated in a detailed re- port (12, 13). The field work was essentially designed to provide input to the Task 6 design studies and to provide support to the Task 4 studies. A wide range of geotechnical exploration was undertaken at the Devil Canyon and Watana sites, reservoirs, and access ·roads ?:Ctd transmission line · routes, together with comprehensive evaluation and documentation of the results. This work included preparation of: I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I -Geologic maps, both regional and site specific; -Geologic sections; -Descriptive and graphic borehole logs; -Descriptive test trench logs; -Field inspection borehole and test trench logs; -Photogeologic maps; -Borehole rock core photographs; -Low level air photointerpretation; -Seismic and resistivity bedrock profiles; -Radar· imagery interpretation maps; -Geotechn i ca 1 exp 1 oration program summaries for proposed structures and material borrow areas (1980~ 1981, 1982); -Data summaries for: -In-hole seismic testing. -Borehole camera studies. -Laboratory testing of construction materials. (b) 1980 Program Th~ geotechnical exploration programs in the field were severely con- strained by difficulties of access and maneuverability of equipment imposed by weather conditions and the requir·e~ents for environmental preservation. The 1980 geotechnical exploration program was designed to identify and in;,. vestigate in limited detail those geological and geotechnical conditions which were likely to significantly affect the-feasibility of the proposed dam projects. Limited preplanning opportunities, requirements for permits from state regulatory agencies, and climatic constraints were such that investigations in 1980 were somewhat limited in scope, and the data limited in detail. Emphasis was therefore placed on identifying and investigating to the maximum extent the most adverse geotechnical conditions encountered. (c) 1981 Program The objectives of the 1981 geotechnical exploration program were to invest- igate in more detail those geological and geotechnical conditions, both general and adverse, which significaf)tly affected the design and construe .. tion of the proposed dam projects, and to obtain the maximum amount of geo- technical design data as possible in the time available. The scope of the exploratory work and the data produced in 1981 was by no means intended to 3-9 be fully comprehensive for project designs~ but rather to establish with reasonable confidence the feasibi·l ity and total cost of the project,-access roads, and transmission lines. The exploratory programs in subsequent years wi11 be yet more detailed, and aimed at providing greater certainty in the design of major dams and structures with a view towards further en- suring the safety of structures while minimizing potential project cost overruns because of unforeseen geotechnical design conditions. 3.7 -Task 6: Design Development As originally conceived in the February, 1980 POS, this Task involved the ini- tial planning studies and selection of an appropriate Susitna development, in- cluding the evaluation, analysis and review of all previous engineering studies related to hydroelectric development of the Upper Susitna River Basin, and the development of preliminary engineering design and cost information for the sel- ected Watana and Devi 1 Canyon Uam projects with all associated intake, ,outlet works, spillways, and power facilities to allow preparation of the project feas- ibility report. Further expansions of the scope of Task 6 studies were included in Revisions 1 and 2 to the POS to give added consideration to Railbelt region generation planning studies with and without the proposed Susitna project, and to develop additional estimates of project construction cost for planning purposes. . Activities under Task 6 were essentially divided into two phases. The first was devoted to considerat~~r, of alternatives and selection of an optimum plan for development of the Susi"'~na River Basin, the second to preliminary design and assessment of the technical and economic feasibility of the selected develop- ment. (a) Development Selection The first phase of studies culminated in a recommended Susitna Basin devel-· opment-plan in March, 1981 (14). These studies involved consideration of development of all identifiable hydroelectric sites in the Susitna River Basin 80 as we 11 as elsewhere in the Rail be 1 t. A 1 tern at ives i nvo 1 ving staged developments were also evaluated. Preliminary comparisons were un- dertaken_ on the basis of conceptual project designs at each site in terms of technical, economic, and environmental aspects. Early consideration was given to the technical feasibility of construction of an arch dam at the Devil Canyon site, as proposed in earlier studies by the USBR and COE .. Alternative Susitna developments, involving constr:uction of tunnels up to ~30 miles long in lieu of a Devil Canyon dam and reservoir, were also evaluated (15). (b) Feasibility Assessments The second phase of studies is essentially the subject matter of this re- port.· The work undertaken involved a comprehens·ive evaluation of the pro- ject developments at the Watana and Devil Canyon sites. These studies in- cluded consideration and selection of optimum solutions for a varietyof .. .• : I I I I I~- I I' I I I I I I I I I I •• I I I I I I I I I I I I I I I I I . "' project arrangements as well as alternatives for major structures such as dams, spi 11ways, power faci 1 it i es, and river divers ion schemes at each site, in terms of technical feasibility, cost; and environmental impact .. · Appropriate criteria were established for hydraulic seismic, geotechnical and structural designs on the basis of the data developed under other areas of the study. These designs were also intended to be used for inclusion in the FERC license application. 3.8-Task 7: Environmental Studies The overall objective of the environmental studies was to describe the existing environmental conditions, evaluate alternatives in light of the existing condi- tions and, for the selected alternatives, predict future conditions with and without the proposed project so that changes (impacts) caused by the project may be assessed. (a) Basis of Studies .· To accomplish the overall study objectives, the following activities were undertaken by the environmental study team: -Participation with the design team in selection of the best alternatives for power generation, access road and site facility locations, and pm'ler transmission corridor based on the environmental impact of the proposed fac i1 i ty; -Preparation of the exhibits required to support the FERC license applica- tion; Responses to inquiries from local, state, and federal agencies, and pub- 1 ic participants at the request of the Power Authority; -Appropriate execution and coordination of field and office activities for all environmental base line studies and impact assessment; -Monitoring of all field activities for environmental acceptability; and -Development of environmental mitigation plan in consultation with the design team and external agencies. Intensive baseline and impact-related investigations were performed over a two year period with the work progressing from general to· specific as the project definition was developed. Because of the magnitude of the proposed act ion, the 1 ife eye le of some of the resources to be impacted, and the time required to evaluate alternatives and develop design specifications, it was recognized that some environmental studies should be continued be- yond the time of license application. Thus, one important element of the early studies was to initiate baseline studies and to develop detailed plans of study for the further environmental impact analysis that will be completed after the license applicatio~ submission, but prior to a final FERC decision on the license application. 3-11 (b) Studies Undertaken The environmental program was primar_ily designed to eva1 uate the Sus itna Hydroelectric Project and associated facilities, with respect to environ- mental impacts. To accomplish this, a comprehensive program of field and office studies was developed in the February, 1980 POS to address the fol- lowing topics: -Water Resources (Quality) Analysis: -Socioecnomic Analysis; -Cultural Resource Investigation; -Land Use Analysis; Recreation Planning; -Susitna Transmission Corridor Assessment; . -F~sh Ecology Studies; -Wildlife Ecology Studies; -Plant Ecology Studies; -Geological Analysis; -Access Road Environmental Analysjs; and -Preparation of FERC License Application Environmental Exhibits. The scope was also structured to provide appropriate coordination of the various environmental study topics and groups and to monitor field a~tiv ities for environmental acceptability. As a resource to concerns expressed by some agencies, the scope of work was further expanded in Revision 2 to the POS to provide for additional data collection and evaluation activities for sediment data for the lower Susitna River, water quality, further quantification of project socio- economic impacts, inclusion of sociocultural impact assessments, fish ecol- ogy dissolved gas investigations, downstream river plant ecology assess- ments, and alternative access corridor environmental assessments. Periodic progress reports summarizing the activities~ results, and conclus- ions of the studies performed were issued at appropriate stages of the major study topics. These reports formed the bas is of s ubmitta 1 s to var i- ous state and federal agencies, whose responses have been and will continue to be considered in formulation of Susitna project designs and in the FERC license application. 3.9 -Task 8: Transmission The work undertaken under Task 8 was essential1y to consider alternative trans- mission corridors, select the transmission route, and produce conceptual designs and cost estimates for the feasibility report and FERC 1 icense application for the following components of the Susitna Project: -Transmission 1 ine 1 inking the project dams ites to Fairbanks and Anchorage, with potential intermediate substations to feed local communities; -Substations, with particular reference to the two major terminals serving Fairbanks and Anchorage, together with a suitable design for intermediate load points; and 3-12 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I jl -Dispatch center· and corrmunicat ions system. The basic approach to the work in this task included review of earlier reports prepared by IECO and ·the. COE with respect to their approach and their level of detail; Following this, more detailed study and conceptual design was under- taken up to a level appropriate for the FERC license submission and for assess- ment of basic technical and economic feasibility. Included in this work was the utilization of geologic and climatologic field data obtained during the study period. (a) Corridor Selection Studies The main ·thrust of studies undertaken through early 1981 involved selection and evaluation of alternative transmission corridors for the proposed Susitna project (16). Associated with this work were studies related to transmission lines for power generation alternatives also under considera- tion, together with preliminary assessments of design requirements for the Susitna Transmission system. 1b) Transmission Line Design and System Studies Subsequent studies involved transmission line route selection, transmission system analysis, and development of basic design information dealing with the following aspects: -Transmission Line Voltage Level . Tower types; . Route map; . Conductor data; . Insulation levels; . Construction access; . Construction schedule; and . Cost estimates. -Substations . Single-line diagrams for each main type of substation; . General arrangement drawings; . Transformer criteria; . Circuit-breaker criteria; . Outline of relay protection philosophy; and • Cost estimates. -Dispatch Centel" and Communications . Location and size of center; Level of automation proposed for remote stations; . Extent of real-time functions required; . Type of communication channe 1 proposed together with appropriate data transmission rates; • Basic type of softw.are; and . Man-Machine interface. 3-13 I I 3.10 -Task 9: Construction Cost Estimates and Schedules The basis of Task 9 was the development of comprehensive, contractor-type, con- struct ion cost estimates for each major element of the proposed Sus itna Hydro- electric Project, detailed engineering and construction schedules, and an asso- ciated analysis of potential contingency constraints and impacts. The development of these estimate~ and schedules took place in parallel with design development, and included assembly and preparation of: -Cost and schedule data; -Preliminary cost estimates; -Cost estimate update; -Engineering/construction schedule; and -Contingency analysis. Th~final products of this task were developed for the project as proposed in this report. (a) Task uutput The primary outputs of Task 9 were the cost estimate summary reports and construct ion schedules appropriate for the assessment of feasibility of the selected Susitna project and for inclusion in FERC licensing documentation. These documents were also prepared to be suitable. for continuous updating and/or modifications during the subsequent study period through commence- ment of constructi.on. They are also appropriate for use in preparation of engineers• estimates during the construction and equipment supply contract bidding phases of the project. (b) Description of Work The 'IJork undertaken in Task 9 provides the basic framework for more de- tailed planning, marketing, and financing of the Susitna Project to be un- dertaken during the period following submission of the FERG License Appli- cation through commencement of construction. This portion of the study was divided into two parts. During the initial part of Task 9 activities, the information systems and basic mechanisms necessary to develop the cost estimates and schedules were established as a basis for selection of the optimum Susitna development. The second part of Task 9 activities wa~; de- voted to the incorporation of more up-to-date information and appropriate revisions of the estimates and schedules for feasibility assessment of the project, prior to submission of the FERC License Application~ For ongoing cost estimating and scheduling purposes, a continuous exchange of informa- tion was necessary with Task 2 -Surveys, Task 5 -Geotechnical Explora- tion, Task 6 -Design Development, Task 7 -Environmental Studies, and Task 8-Transmission Activities. 3.11 -Task 10: Licensing The overall basis for Task 10~and, in fact, the ultimate oojective of the entire POS~ was to provide for timely preparation and assembly of all documentation 3-14 I I I I 1-, I I! I I I I I I I I I I :I I I I I I I I I I I I I I I I I I I I I necessary for app1 ication for 1 icense to the Federal Energy Regulatory Commis- sion (fERC). Should the feasibi1 ity assessment addressed in this report be accepted by the State, the output from this task will be used as a. bas is for submission of a completed application for 1 icensing the Susitna Hydroelectric Project,. (a) Hasis of POS As originally conceived in the February, 1980 POS; preparation of the license would have been based on the then-current FERC regulations which required submission of Exhibits A through W (less P and Q, which were not required for licensing a major hydroele~tric project). Assuming that technical and economic feasiblity of the project were e.stab- 1 ished and that environmental impacts and proposed mitigatory act ions were acceptable, the major target toward which a11 other work in the POS was aimed was the successful completion of a 1 icense application to FERC.. In- deed, the entire POS was prepared in such a manner that only those tasks and subtasks considered to be the minimum necessary for acceptance by FERC of the license application were included in the first 30 months of effort. Although it was recognized that . a significant amount of fo 11 ow•on work would necessarily have to be accomplished prior to eventual project con- struction; the historically lengthy periods ass-ociated with federal pro- cessing of applications clearly suggested that the earliest possible sub- miss ion was in the best interest of the Power Authority. It was decided entirely appropriate to file an appl1cation which meets minimum require- ments for submission, while at the same time detailing plans for initiation or continuation of studies whose results may be required before the 1icense itself was actually awarded. (b) ·Revised FERC Regulations The revision of the FERC requirements in late 1981 to five exhibits: A through E~ did not effectively alter the scope ot direction of the study. The revised regulations altered the format rather than the total content of the application.. However, encouraging indications of a speed-up in the FERC 1 icensing process and a desire to allow agencies additional time for constructive input to the project planning process led to revision 3 to the POS in February, 1982. In this revision, the scheduled date for the li- cense submittal is postponed by three months to September 30, 198.2. This also allows for incorporation of additional environmental data into the application documents. In accordance with FERC requirements, significant efforts have been made by the study team to assist the Power Authority in setting up a constructive FormC!l Agency Coordination process. This process is designed to allow feder,,.1, state, and local agencies the opportunity to participate in appro- priate decision phases of the study and to ensure that acceptable mitiga- tion measures are incorporated in the development of project designs where necessary .. 3-15 " -----'----------_,_::.,________, ___ __::______ ____ ---"-......;.. _____ -"--' 3.12 -Task ll: . Marketing _and Financing Activities to be undertaken in this Task were aimed at examining in some detail_~ the potential Rai1belt market for Susitna Power, the possible mechanisms through- which the Power Authority might obtain adequate financing for this large. unde.r- tak ing, and an appropriate return on the investtnent.. Direct state participation in the financial support of the Susitna and other hydroelectric developments in Alaska, has been the subject of a number of pr.oposed and enacted state leg is 1 a- tion over the period of the feasibility study. This, along wtth the inevitable .uncertui nty i-ntrinsic to the: financing of such 1 arge projects under current marl<et conditions, has. made ·a somewhat difficult to determine specific financ- ing mechanisms. The scope of this task \>Jas the subject of a major modification under Revision 1 to the POS in September, 1980, and has been further modified from time to time during the feasibility study. (a) Basis of Studies ,. ,, I I: \ I I I ' : The determination of power and energy outputs from the proposed project, the matching of this input with Railbelt demand over the li-fe of the pro- ject, and the cash flow requirements fcir construction of the project were key -products.,.of-the feasibility assessment which provided the basis of marketing and financing studies. · ······l·i ,.!. . ' ! '· I It was recognized that if the. Susitna Project is selected as an appropriate element in the growth of generating capacity in the Railbelt region, it is likely to proceed on the basis of a partial or complete project financing. Essential to this is a reasonably accurate determination of revenues and properly established energy sales agreements. Furthermore, all project risks must be identified, their potential impact assessed, and appropriate contingency plans and provisions made. (b) Risk Assessments As the various elements of the project study reached the appropriate level of completion, a rigorous analysis of risk was applied as a basis for recommended contingency provisions. The approach used involved modern techniques of analysis and probability assessment and dealt with cost~ schedule, technical, and other controlling elements of the project~ Risks assessed included those associated with the planning, design and con- struction of the project, as well as the financing of it. There. were a number of basis project financing risks which were addressed, including: __ ..., .Co.st over.runs prior to camp 1 et ion; -Late completion and non-completion; -Partial or total post-completion outages; -Customer fai 1 ure to provide anticipated cash flows; -Regulatory risks, particularly insofar as new regulations affect the op- eration (and, therefore, of course,-the profitability and/or consumer costs); and -Technological risks, particul arJy insofar as the extent to which new or relatively unproven technology may increase financing difficulties. 3-16 I .1_.:·1· -I I I :.\ i 1 .. : e ' I; . I : '. I I .,. ··~·-. . I I I I I' I -;· ,·· I I ~--· ·~ I I I I I I ,I I I. I I I· I I I I I 3 .. 13-Task 12: Public Participation Program The essential objective of the Public Participation Program was and is to keep the public fully informed of plans, progress, and findings associated wi.th con- duct of the detailed feasibi1 ity study .. The program also provides a means whereby the public (including individuals, public and private. organi_zations, and various government agencies) can inf1uence the course of the work. The program has been conducted effectively since commencement of the study and _ outputs have incladed: Records of the proceedings of public meetings, together with written comments and proposed action lists derived from public inputs;. -Periodic newsletters to address specific topics of public concern; -Records of workshop meetings; -Records of deliberations of external environmental and engineering bdards; -Written responses to individual letters of inquiry addressed to the project in format ion office; -Action _lists, together with notes as to status of pending actions; -News releases; -Audio visual recordings; and -Displays set up with periodic update. The management of the Public Participation Program has been undertaken through- out the study by the Power Authority staff~ .Members of the study team partici- pated in the program as necessary by attendance at meetings and preparation of appropriate information documents and responses to questions. 3-17 LIST OF REFERENCES (1) (2) (3) Acres American Incorporated, .§us itna ,H.Ydro.e1 ectric Project ... Plan of Study, prepared for the Alaska Powe\ .. · Authority, Febr·uary 1980. Acres American Incorporated, Susitna Hydroelectric Project .. Plan of Study -Revision 1, prepared for the Alaska Power Authority, September 1980 .. Acres American Incorporated, Susitna Hydroelectric Project.-Plan of Study .... Revis ion 2, prepared for the Alaska Power Author tty, December 1981. ' -(4) Acres American Incorporated, Susitna Hydtoelectric Project -Plan of Study ---,-_,_, '""'' -Revision 3, prepared for the Alaska Power Authority, February 1982. (5) Alaska District, U.S. Army Corps of Engineers, Plan of Study for Jiydropower Feasibility Analysis, prepared for the State of Alaska, June 1978. (6) Acres American Incorporated!, SusitnaHydr·oelectric Project~-Task 1 Power· Studies -Subtask 1 .. 01 Closeout Report, Review of ISER Work, prepared for the Alaska Power Authority, December 1980~ (7) Wood.~ard-Clyde Consultants, Forecasting Peak Electrical _Demand for A1 ask a's Ra1lbelt, prepared for Acres J.Vnerican Incorporated, December 1980. (8) Acres American Incorporated, Susitna Hydroelectric Project, Task 1 Power Studies, Termination Report, prepared for the Alaska Power Authority; September 1980 • t I 1 I ,, I I I I :1 . (Y) R&N Consultants, Susitna Hydroelectric Project, Task 2-Surveys and Site Facilities, Access Planning Stud,x, prepared for Acres American I Incorporated, January 1982~ • . . (10) Woodward-Clyde Consultants, Intefim Report on Seismic Studies for Susitna Hydroelectric Project, prepared for Acres American Incorporated, December 1980. (11) Woodward-Clyde Consultants, Final Report on Seismic Studies for Susitna .tl1droelectric Projecta prepared for Acres American Incorporated, February 1982. (12) Acres Amercian Incorporated, Susitna Hvdroelectric Project, 1980 Geotechnical Report, prepared for the Alaska Power Authority, June 1981. (13) Acres Amer~can Incorporated, Susitna Hydroe.Jectric Project, .1980-81 Geotechn 1 cal Report, prepared for th~ Alaska Power Author1 ty, February . 1982. (14) Acres American Incorporated, Susitna Hydroelectric Project, Development Selection Report, prepared for the Alaska Power Authority, June 1981. 3-18 { I I I I :t I ·I ,I . 0 • -~ .... '··-,_,_ __ ....... ~-~ ..... ~ .... ~.-. ....... ~-~-.t•1=·.,r·= .. ~ ....... .;,;.~~-.., • ....:.t~·"'~-·"···~~ .... ,.,~J\, z·-· ~-·""~: __ t...__ ..... I ·I .. ~-. I I I -I I I I 'I I I 1: I •• I .I I I . biST OF REFERENCES (Cont'd) i lt.··· ~ ,, j Acres American Incorporated, Susi.tna Hydroelectric Project; Tunnel Alternative Report, prepared for the Alaska Power Authority, July 1981. (16) Acres American Incorporated, Susitna Hydroelectric Project, Transmission ~ine Corridor Screening Closeout_ Report, prepared for Alaska Powet' Authority, September-1981. 3-19 •' '?"¥-. ~ • ·• I • ,. I I I •• I I I I I I I I I I I I I I I >'. 4 -PREVIOUS STUDIES In this section of the report a summary is presented of studies undertaken by the USBR, the COE and others over the period 1948 through 1979 • 4c.l -Early_Studies of Hydroelectric Potential Shortly aftt:r World War II ended the USBR conducted an initial investigation of hydroelectric potential in Alaska, and issued a report of the results in 1948. Responding to a recommendation made in 1949 by the nineteenth Alaska territorial legislature that Alaska be included in the Bureau of Reclamation program, the Secretary of Interior provided funds to update the 1948 work. The resulting report, issued in 1952, recognized tha vast hydroelectric potential within the- territory and placed particular emphasis on the strategic location of the Susitna River between Anchorage and Fairbanks as well as its proximity to the connecting Railbelt (See Figures 1.1 and 4.1). . A series of studies was commissioned over the years to identify dam sites; and conduct geotechnical investigations. By 1961, the Department of the Interior proposed author·izati on of a two dam power system i nvo 1 vi ng the De vi 1 Canyon and the Denali sites {Figure 4.1). The definitive 1961 report was subsequently updated by the A 1 ask a Power Admi ni strati on (an agency of the USBR) in 1974 ~ at which time the desirability of proceeding with hydroelectr~c development \'las reaffirmed. The COE was .also active in hydropower investigations in Alaska during the 1950's and 1960's, but focused its attention on a more ambitious development at Rampart on the Yukon River. This P~'"oject was, capable of generating five times as much elect~ic energy as Susitna annually. The sheer size and the technological chal- lenges associated with Ramp~rt captured the imagination of supporters and effectively diverted attention from the Sus.itna Basin for more than a decade. The Rampart feport was finally shelved in the early 1970's because of strang environmental concerns t:nd the uncertainty of marketing prospects for so much energy, particularly in 1 i ~Jht of abundant natura 1 gas which had been discovered and developed in Cook Inlet. The energy crisis precipitated 'by the OPEC oil boycott in 1973 provided some further impetus for seeking deve 1 opment of renewab 1 e resources. Feder a 1 funding was made available both tc, complete the Alaska Power Administration 1 s update report on Susitna in 1974 and to launch a prefeasibility investigation by the COE. The State of Alaska itself commissioned a reassessment of the ~usitna Pro- ject by the Henry J. Kaiser Company in 1974 .. Although the gestation period for a possible Susitna Project has been lengthy:t Federal, State, and private organizations have been virtually unanimous over the years -in recommending that t.he project proceed. Salient features of the various reports to date are outlined in the following sections. 4.2-u.s. Bureau of Recla.mation~-1953 Study The USBR 1952 report to the Congress on A 1 ask a 1 s avera 11 hjdroe 1 ectr.i c potential was followed shortly by the first major study of the Susitna Basin in 1953. Ten dam sites were identified above the railroad crossing at GoldCreek (see also Figure 4.1): .':l 4-1 -Gold Creek -Olson De vi 1 Canyon -DE:Vi 1 Creek -Watana -Vee. -Maclaren -Denali -Butte Creek -Tyone (on the Tyone River) Fifteen more sites were considered below Gold Creek. Ho\'tever, more attention has been focus-ed over the years on the Upper Susitna easin where the topography is better suited to dam construction and whe.'re less impact on anadromous fisher-- ies is expected. Field reconnaissance eliminated half the original Upper Basin list and further USBR consideration centered on Olson, Devil Canyon, Watana, Vee and Denali. All of the USBR studies since 1953 have regarded these sites as the most appropr·i ate for further investigation. 4.3 -u.s. Bureau of Reclamation -1961 Study In 1961. a more detailed feasibility study resulted in a recomme.nded five stage development plan t9 match the load growth curve as it was then projected. Devil Canyon was to be ·the first deve 1 opment--a 635 feet high arc~r dam with an i nsta 11 ed capacity of about 220 MW. The reservoir formed by the De vi 1 Canyon dam alone would not store enough water to permit higher capacit)es to be econom-· ically installed since long periods of relatively low flo\'t occur in the winter months. The second stage would have increased storage t;apacity by adding an earthfill dam at Denali in the upper reaches of the basin. Subsequent stages involved adding generating capacity to the Devil Canyon dam. Geotechnical investigations at De vi 1 Canyon were more thorough than at Dena 1 i. At Dena 1 i , test pits were dug, but no drilling occurre~. 4.4 -Alaska Power Administration-1974 ·· 0 Little change from the basic USBR-1961 five stage concept appeared in th~ 1974 report by the Alaska Power Admi ni strati on. This 1 ater effort offered a more sophisticated design, provided new cost .and schedule estimates, and addressed marketing, economics., and environmental considerations. 4.5-Kaiser Proposal for Development The Kaiser study, commissioned by the Office of the Governor in 1974., proposed that the initial Susitna development consist of a single dam known as High Devil Canyon {See Figure 4.1). No field investigations were made to confirm the tech- nical feasibility of the High Devil Canyon location because the funding level was insufficient for such efforts. Visual observations suggested the site was probably favorable.. The USBR had always been uneasy .about foundation conditions at Denali, but had to rely upon the Denali reservoir to provide storage during long periods of low flow. Kaiser chose to avoid the perceived uncertainty at Dena 1 i by proposing to build a rockfi 11 dam at High De vi 1 Canyon which, at 810 feet, would create a large enough reservoir to overcome the storage problem. Although the selected sites \'lere different, the COE reached a similar conclusion when it later chose the high dam at Watana as the first to be constructed. 4-2 I I I I I I I I· I ~· :I I; I I I I I I' I I I I -I· I I I I I I I I I I I I I I I Subsequent developments suggested by Kaiser included a dovmstream dam at the Olson Site and an upstream dam at a site known as Susitna III (see Figure 4 .. 1). The information developed for these addit~onal dams was confined to estimating energy potential. As in the COE study, future development of Denali rema'illed a possibility if foundation conditions were found to be adequate and if the ¥,a1ue of additional firm energy provided economic justification at some later date. Kaiser did not regard the development of an energy consumptive aluminum plant as necess.ary to economically justify its proposed project. 4.6 -u.s. Army Corps of Engineers -1975 and 1979 Studies The most comprehensive study of the Upper Susitna Basin prior to the current study was completed in 1975 by the COE. A total of 23 alternative developi::i:nts were analyzed, including those proposed by the USBR as wt:ll as consideraticn of coal as the primary energy source for Railbelt electrical needs. The COE agreed that an arch dam at Devi 1 Canyon was appropriate, but found that a high da.~ at the Watana site would form a large enough reservoir for seasonal storage·and would permit continued generation during low flow periods. The COE recommended an earthfi11 dam at \~atana with a height of 810 feet.. In the longer term, development of the Denali site remained a possibility which!\ if constructed, \'/OUl d i~crease the amount of firm energy available, even in ttery dry years. An ad-hoc task force was created by Governor Jay Hammond upon completion of the 1975 COE Study. This task force recommended endorsement of the COE request for Congressional authorizatlon, but pointed out that extensive further studies~ particularly those dealin£' with envir·onmental and socioeconomic questions~ \.Yere necessary before any construction decision could be made. At the Feder a 1 1 eve 1, concern was expressed at the Office of r~anagement an:d Bud- get regarding the adequacy of geotechnical data at the Hatana site as \'/ell ~s the validity· of the. economics. The apparent ambitiousness of the schedule and the feasibility of a thin arch dam at Devil Canyon were also questioned. Further investigations were funded and the COE produced an updated report 'lin 1979. Devil Canyon and \~atana were reaffir·med as appropriate sites, but an~er native dam types were investigated. A concrete gravity dam \'/as analyzed as an a 1 tern at i ve for the thin arch dam at De vi 1 Canyon and the vJatana dam ~tas changed from earthfi 11 to rockfi 11. Subsequent cost and schedule estimates still ·Sndi- cated economic justification for t~e project. 4-3 ------------------- 5 0 5 15 r·~"i SCALE IN MILES LEGEND TYONE" & DAMSITE. SUSITNA m (NO DEFINITE(!. LOCATION) u DAMSITES PROPOSED BY OTHERS \ \ \ ~-~ /"' ,r--' l \1 l ~~ I TYONE ~~ ~~ TYONELA~~ SUSITNfi . / LAKE ~ \ J LAKE l.OUISE J r----_/ 1 J . ,-...J""'"""""'_,.v _,_, FIGURE 4 .I I I I I I I I I I I •• I I I I I I: I I 5 -RAILBELT LOAD FORECASTS In this section of the report~ tha process of development of electrical demand forecasts for the Railbelt region is described. Historical and projected trends in the factors which influence such demand are identified and discussed, and the basis of forecasts used in Susitna generation planning studies is presented. The feasibility of a maJor hydroelectric project depends in part upon the extent the available capacity and energy are consistent with the needs of the market to be served by the time the project comes on line. Attempting to forecast future energy demand is a difficult process at best; it is therefm--e particularly important that this exercise be accomplished in an objective manner. For this reason, the APA and the State of Alaska have authorized 1 oad forecasts for the Alaska Railbelt region to be prepared independently of the feasibility study .. 5.1 -Scope of Studies There have been two forecast5 deve 1 oped and used during the feas i bi 1 ity study. In 1980, the Institute for Social and Economic Research ( ISER) prepared economic and accompanying end use energy demand projections for the Railbelt. The end use forecasts were further refined as part of the feasibility study" to estimate capacity demands and demand patterns. Also estimated was the potential impact on these forecasts of additional load management and energy conservation efforts. These forecasts were used in several portions of the feasibility study, including fhe development selection study, initial economic and financial analysis, sensitivity analyses, and ~apacity staging. These forecasts are dis- cussed in more detail in Sections 5.2 to 5.7. In December, 1981, Battelle Pacific Northwest Laboratory produced a revised series of load forecasts for the Raiib·elt. These forecasts were developed as a part of the Railbelt Alternatives Study, done by Battelle under contract to the State of Alaska. Battelle's forecasts were a result of further updating of economic projections by ISER and some revised end-use models developed by Battelle, which took into account price sensitivity and several other concerns not included in the 1980 projections. The 1981 B~ttelle forecasts we~·e used in this feasibility study for the final economic a11d financial analyses presented in Section 18, as well as for reviewing the project staging. The Battelle fore- casts are presented in Section 5.8. 5.2 -Electricity Demand Profiles This section reviews the historical growth of electricity consumption in the Railbelt and compares it to the nat1onal trend. Railbelt electricity .consump- tion is then disaggregated by regions and by end-use sectors to clarify past us age patterns. · (a) Historical Trends " Between 1940 and 1978, electricity sales in the Railbelt grew at an average annual rate of 15 .. 2 percent. This growth was roughly twice that for the naticn as a whole. Table 5.1 shows U.S. and Alaskan annual growth rates· for different periods between 1940 and 1978. The historical growth of Railbelt utility sales from 1965 is illustrated in Figure 5.1. 5-1 Although the Railbelt growth rates consistently exceeded the national aver- age, the gap has been nar·rowi ng 1n 1 ater years due to the gradua 1 maturing of the A 1 ask an economy. Gro\'rt.h in the Ra i 1 be 1 t has exceeded the nat i ona1 average for two reasons: popuiation growth in the Railbelt has -been higher than the national rate, and the proportion of Alaskan households served by electric utilities was lower than the u.s. average so that. some growth in the number of customer's occurred independently of population growth. Table 5.2 compares u.s. and Alaskan growth rates in the residential and commer- cial sectors. (b) Reoional Demand Electricity demand in the Railbe'it, disaggregated by regions, is shown in Table 5.3. During the period from 1965 to 1978, Greater Anchorage account- ed for about 75 percent of Railbelt electric-ity consumption followed by Greater Fairbanks with 24 percent and Glennallen-Valdez with 1 percent. The pattern of regional sharing during this period has been quite stable and no discernible trend in regional shift has emerged. Thi3 is mainly a result of the uniform rate of econo~ic development in t~e ~lask1n Rail- belt. (c) End-Use Consum.P.tion Rail belt e1ectricity consumption by majcr end-usa sector >is shown in Table 5.4. In the residential sector, electricity consumption is largely attrib- uted to space heating; utilities sue~ as refrigerators, water heaters, 1 i ghts and cooking ranges rank next in order of usage. In the commercia 1- industrial-government sector, end-use consumption is less clear because of a lack of data; however, it is r·easonable to assume that electricity is used mainly fm" lighting, space heating, cooling and water heating. Con- sumption in the miscellaneous sector is attributed mainly to street light- ing anrl usage in second homes. The distribution of electricity consumption in these end-use sectors has been fairly stable. ~y 1978, the commercial-industrial-governmen.t and residential sectors accounted for 52 percent and 47 percent respectively. In contrast, the 1978 nationwide shares were 65 percent and 34 percent res- pectively. 5.3 -ISER Electrjcity Consumption Forecast~ .. This section briefly discusses the methodology used by ISER to estimate e.lectric enev"gy sales for the Rai1belt, and summar·izes the results obtained. (a) Methodology The ISER electricity demand forecasting filodel conceptualized in computer 1o"'~~.: the linkage between economic growth scenarios and electricity con- Stl·'$\·•i... ·!'\· The output from the mode 1 is in the form of projected va 1 ues of e1ec...··~;:·lcity consumption for each of the three geographical areas of the Railbelt (Greater Anchorage, G...-eater Fairbanks and Glennallen-Vald~z) and is classified by final use (i.e., heating, washing, cooling, etc.) and con- sum·ing s.ector (commercial, residential, etc). The r110del produces output on a five-year time basis from 1985 to 2010, inclusive. 5-2 :I I I I ··: I I I ,,I: I II I! 1: I I I I I I; I I I I •• I. I I I I ·I I I I I I I ·~ I The ISER model consists of several submodels linked by key variables and driven by ·policy and technical assumptions and state and national trencjs .. · These submodels are grouped into four economic mode 1 s which fqrecast ftJture levels of economic activity and four electricity consumption models which forecast the associated electricity requirements by consuming sectors. _For two of the consuming sectors it was not possible to set up computer models and simplifying assumptions were made. The models and assumptions are described below. ( i) Economic Submode ls -_T~he~M~AP~-~conometric Model MAP is an econometric model based on forecasted or assumed levels of nationz.rl ~conomic trends, State government activity, a.nd developments in the Alaska resource sector .. These economic indi- cators are translated into forecasted levels of statewide popula- :tion by age and sex1 employme.nt by industrial sector!f and income. -The Household Formation Model . The household formation mot:1o:t:1 groups individuals into household uni!:s on the basis of nationa1 and state demographic trends. The output is the forecast number of household heads by age and sex, which is in turn an input tu the housing stock and electricity consumption models. -Regi ana l_A 11ocat ion ~~ode 1 This model disaggregates MAP's projections of population and employment into regions of the Railbelt.. The model uses econo- metric techniques to structure regional shares of state popula- tion, the support sector, and government employment. -Housing Stock Model The housing stock model utilizes the output from the household formation model, the regiG1al population information from the regional allocation model, and the results of an independent survey on housing choice. These outputs are combined to produce the number of housing units by type (e.g. single family, duplex,· multifamily, etc.) and by region for each of the forecast years. (ii) !=lectricity Consumption Submodel§. These submodels are structured to determine electricity requirements for various demand components: -Residential Non-space Heating Electricity Requirements This model estimates electricity requirements for household app 11-~nces ut ·n i zing the fa 11 owing information: 5-3 . " r~ . .-.-r: • • number of households • appliance saturation rate • fuel mode split • avel'"age annual consumption .of appliance • average household size Residential non-space·heating electricity requirements are obtained by summing the electricity requirements of all appli- ances .. -Residential Space Heating This model estimates space heating electricity requirements for four types of dwelling units: single family, duplex, multi- family, and mobile home. The space heating electricity require- ment for each type of dwelling unit is calculated as the product of the number of dwelling units, fuel mode split and specified average levels of consumption. Commercial-Industrial-Government Total electricity requirements for the commercial-industrial- government sector are defined as the product of non-agri cultura 1 wage and salary employment and average electricity consumption per employee. Electr·icity consumption per employee is a function of time and application of conservation standards. This implies that new electricity users in this sector will have difoferent electricity requirements than previous customers. -Miscellaneous This mode1 estimates twu remaining sectors of electricity con- sumption: i.e. street lighting and recreational homes. (iii) fpnsumption Sectors Not Modeled Electricity requirements were not modeled for two sectors of demand: -Military For many reasons, including a lack of historical data, no model is included to correlate military electricity consumption \'lith causal factors. Hence, future electricity requirements for the military are assumed to be the same as the current 1 evel. -Self-Supplied Industrial No model is included to project future self-generated electricity for industry. Existing users are identified and current elec- tricity consumption determined "for APA sources. New u,sers and future consumption levels are identified from economic scenar- ios. 5-4 . . I I I .•. •. . , I I .. I I I I I I I I I I t '1 I I I I I I I I I, I I I I I •• I I I I I (b) Assumptions To make these models operational, a number of additional assumptions are incorporated: -The electricity market is presently in a state of relative equilibrium except for Fairbanks where a shift away from electric space heating is underway. This equilibrium is expected to remain in effect throughout the forecast period because of t'"elatively constant fuel price ratios,. -The price of energy relative to other goods ~d services will continue to rise. Rising real incomes will act to increase the demand for electricity. Federal policies will be effective in the area of appliance energy con-. servation, but will have a much smaller impact on building stock thermal efficiencies .. No state conservation policies directed exclusively toward electricity will be implemented. No ·significant state policies designed to alter the price or availabil- ity of alternative fuels will be implemented. No new electricity technologies will be introduced. In terms of residential appliances: . Saturation rates· will follow national trends; . For some appliances, reduced household size will act to reduce average electricity requirements; . Consumption is a function of the appliance scrapping rate as the average age affects efficiency; .. Unspecified appliance consumption will increase to accommodate the possibility of ne\'1 domestic electricity applications. In terms of residential space heating: A slight trend toward single family homes is projected; . Average housing unit size will continue to grow; Natural gas availability will not significantly increase; . Space heating alternatives such as oil, wood or coal will not greatly affect aggregate space heating demand; . No significant increase in the. number of heat pumps will occur. In terms of commercial--industria1-government use: . Employment will grow more rapidly than the population; . No major energy conservation measures are anticipated; .. The distribution of electricity end-uses will not shift significantly. 5-5 I . -Miscellaneous utility sales (street lighting and second home use} \¥ill grow at rates consistent with predicted total utility sales. · {c) Forecasting Uncertaint,x To adequately address the uncertainty associated with the prediction of future demands, a number of different economic growth scenarios were con- sidered. These were for·mulated by alternatively combining high, moderate and low growth rates in the area of special projects and industry with State government fiscal policies aimed at stimulating either high, moderate or low growth. This resulted in a total of nine potential growth scenarios for· the state. In addition to these scenarios, ISER also considered the potential impact of a price reduced shift towards increased electricity demand. As outlined below, a.short list of six future scenarios was selected. These concentrated around the mid-range or ''most 1 ike ly 11 esti- mate and the upper and lower extremes. {d) Initial ISER Forecast Results The results of the ISER forecasts prepared in ·1980, which were used as the basis of Susitna development selection studies, were as follows: (i) Base Case The ISER forecast which incorporates the combination of moderate economic growth and moderate government expenditure was considered to be the "most likely" load forecast. This has been identified for the purpose of this study as the "Base Case Forecast.". The resu 1 ts of this forecast are presented in Table 5.5 and indicate that utility sales for the Railbelt will grow from thel980 level of 2390 GWh to 7952 GWh in .2010, representing an av~rage annual growth rate of 4.09 percent. Over the period of the forecast, the highest growth rate occurs from 1990 to 2000 at 4. 76 percent, fall owed by a decline to 3.33 percent during the 2000 to 2010 period. (ii) Range of Forecasts In addition to the base case, the initial ISER results incorporated a higher and 1 ower rate of economic growth coupled with moderate government expenditure, and they also incorporate the case where a shift to electricity takes place. These forecasts did not provide a complete envelope of potential grm'lth scenarios because the impacts of high industrial growth/ high government expenditure and low industrial growth/low government expenditure on electricity demand have not been included. Estimates of these impacts have been computed by the method of proportionality as approximations to the model runs. A summary of aggregate Railbelt electricity growth for the range of scenarios is presented in Table 5.6 and in Figure 5 .. 2. The medium growth rate of 4.1 percent is shown to be bounded by lower and upper limits of 2.8 percent and 6.1 percent respectively. In comparison, historical electricity demand in the Railbelt has increased by 11 percent. 5-6 0 i1 I 1 I I I I I I I I I I I I I I I I I I •• I I I I I I I I :I I I I I I I .I . . . • • • 1 • • .· . . . ~ . •: 5.4 -Past Projections of Railbelt Electricity Dema!J.Q_ A number of electricity projections have been developed in the past. The dis- cussion here is confined to work conducted since 1975 in order to compare ISER•s forecasts with previous work and to rationalize any differences that occur .. Forecasts of electric power requirements developed since 1975 (excluding ISERts latest forecast) are summarized in Table 5.7. A cursory examination indicates that differences which occur in the early years progressively increase within the forecast period. The performance of these forecasts can be ascertained by comparing them to 1980 utility sales. Table 5.8 shows the pE;:rcent error in the forecasted growth rate to 19.80. As can be seen, all of the forecasts significantly overestimated 1980 consumption. These forecasts are also significantly different from those developed recently by ISER; the differences are mainly attributed to assumptions concerning economic growth and electricity consumption rates. Although the economic growth assumptions incorporated in previous studies have varied widely, they have been generally more optimistic with respect to the type, size and timing of projects and other economic events. This has consequently resulted in higher projections of economic activity compared to the recent ISER study. Electricity consumption rates in the ISER studies are generally lower than those in previous studies. This is essentially because ISER has been the first to incorporate estimates of appliance saturation rates, end-use patt'erns and con- servation measures. 5.5 -Demand Forecasts An important factor to be considered in generation planning studies is the peak power demand associated with a forecast of electric energy demand. The overall appt"oach to derivation of the peak demand forecasts for the Railbelt Region was to examine the available historical data with regard to the generation of electrical energy and to apply the observed generation patterns to existing sales forecasts. Information routinely supplied by the Rail belt utilities to the Federal Energy Regulatory Commission was utilized to determine these load patterns. {a) Load Patterns The analysis of load patterns emphasized the identification of average pat- terns over the 10-ye-ar period from 1970 to 1979 and did not consider trends or changes in the patterns with time. Generally, ~the use of average values was preferred as it reduced the impact of yearly variations due to variable weather conditions and outages. In any event, it was not possible to detect any patterns in the avail able data. The average hourly distribution of generation for the first weeks of April, August and December was used to determine the typical average load pattern for the various utilities. As a result of the relatively 1 imited data base,. the calculated load duration curve would be expected to show less variation than one computed from a more complete data base resulting in an overestimation of the load factor. In addition, hourly data also tend to average out actual peak demands occurring within a time interval of less 5-7 than one hour. This could also lead to overestimation of the load factor. It is, however, believed that the accuracy achieved is adequate for these studies, particularly in light of the relatively much greater uncertainties associ a ted \'lith the 1 oad forecasts. {b) Sales Allocation Although the above load data are available by utility, the kvlh sales fore- casts are based on service area alone.. The kWh sales data were allocated to the individual utilities utilizing a predicted mix of consumer cate- gories in the area and the current mix of sa 1 es by consumer category for the utilities serving the area. (c) Peak Loads The two data sets were comb·ined to determine composite peak loads for the Rai lbelt area. The firs-c step involved an adjustment to the allocated-sales to reflect 1 asses and energy unaccounted foro The adjustment was made by increasing the energy allocated to each utility by a factor computed from historical sales and generation levels. This resulted in a gross energy generation for each utility. The factors determined for the monthly distribution of total annual genera- tion were then used to distribute the gross generation for each year. The resulting hourly loads for each utility were added together to obtain the total Railbelt system load pattern for each forecast year. Table 5.9 summarizes the total energy generation and the peak 1 oads for each of the low, medium, and high I.SER sales forecasts, assuming moderate government expenditure= The load factors computed in this study average seven percentage points higher than the average load factors observed in the four utilities over the 10-year period. 5o6 -Potential for Load Management and Energy Conservation ·utilities nationwide are .currently paying increasing attention to the implemen- tation of load management and conservation measures in an attempt to reduce or shift peak load and to reduce energy demand.. Load management is defined as the "shiftingn and corresponding reduction of peak demands and the alteration of daily 1 oad shapes by means of appropriate measures. Although some 1 oad manage- ment techniques can result in a slight increase in daily energy demand, the objective is essentially to accomplish a reduction of peak demand with no signi- ficant difference in total energy demand. Load management may generally be achieved by one of two methods: direct control, 1n \'lhich the utility controls . the end-use devices; or indirect control, in which price incentives are used to motivate load shifting by the consumer. Conservation is defined as a net reduc- tion in energy demand by means of appropriate measures, with a corresponding reduction in peak demand. 5-8 .. I I I I I I I I I I I I I I I I I I I ,I I I I I I I I I I I I I I I I I I 'I The potential benefits of power demand control and reduction measures require careful evaluation before implementation on a major scale. A considerable amount ·Of research and development work has been undertaken in the Lower 48 to develop methods and cost strategies, and to assess the potential impact of such strategies on demand. As a result of this work, load management and energy con- servation concepts have either been imp 1 emented or are being plan ned by many util itie.s. The ·anticipated effects on the growth of future peak load and energy consumption in the utility systems have been included in their forecasts. Currently in Alaska, at least one utility, Anchorage Municipal Light and Power, is known to have instituted an experimental time-of-day rate for electricity. Although conservation is essentiallY accomplished by a reduct·~on in demand, it may also be regarded as a means of diverting available energy to other uses, or creating -a 11 new 11 source of energy. A recent study by the Alaska Center for Policy Studies indicated that conservation was the most economically attractive source of new energy available to the Railbelt area. This conclusion was based on evidence from existing weatherization programs and projections from the Alaska Federation for Community Self Reliance in Fairbanks. However, the total amount of energy that can be made available by such means is relatively small compared to the total Railbelt system energy demand up to the year 2010., The ISER forecasts incorporated the impacts of certain ener~ conservation measures, but did not include any load management. In this study, opportunities for implementation of additional programs of intensified conservation and load management measures are considered in the generation planning studies. These are d~scussed in more detail in the following section. 5.7 -Load Forecasts Used for Development Selection Studies This section outlines the adjustments that were made to produce the total Rail~ belt system electricity forecasts ·to be used in the development selection stud- ies described in Section 8. (a) Adjusted ISER Forecasts Three of the initial ISER energy forecasts were considered in generation planning studies for development selection studies (see Table 5.6). These included the base case (MES-GM) or medium forecast, a low and a high fore- cast. The 1 ow forecast was that corresponding to the 1 ow economic growth as proposed by ISER with an adjustment for low government expenditure (LES-GL). The high forecast corresponded to the ISER high economic growth scenario with an adjustment for high government expenditure (HES-GH). The electricity forecasts summarized in Table 5.9 represent total utility generatton and include projections for self-supplied industrial and mili- tary generation sector.s. Included in these forecasts are transmission and distribution losses in the range of 9 to 13 percent depending upon the gen- eration scenario assumed. These forecasts, rat~ging from 2. 71 to 4. 76 per- cent average annual growth, were adjusted for use in generation planning studies. 5-9 \: '-*''~ . ..ft...,.__. The self-supplied industrial energy primarily involves drilling and off- shore operations and other activities which are not likely to be connected into the Railbelt supply system. This component, which varies depending upon generation scenario, was th~refore omitted from the forecasts used for planning purposes. The military is likely to continue purchasing energy from the general mar- ket as long as it remains economic. However, much of their generating capacity is tied to district heating systems which would presumably continue operation. For study purposes, it was therefore assumed that 30 percent of the estimated mi 1 i tary generation waul d be supplied from the grid system. The adjustments made to power and energy forecasts for use in self-supplied industrial and military sectors are reflected in Table 5.10 and in Figure 5. 3 The power and energy values given in Table 5.10 are those used in the generation planning studies. Annual growth rates range from 1¢99 to 5.96 percent for· very low and high forecasts with a medium generation forecast of 3.96 percent. (b) Forecast Incorporating Load Management and Conservation In order to eva 1 uate generation plans under extremely 1 ow projected energy growth rates, the low forecast was furthet· adjusted downward to account for additional load mc:nagement and energy conservation. The results of this scenario also appear on Table 5.10. -ISER Conservation Assumption..§_ For the residential sector, ISER assumed the federally-mandated-efficien- cy standards for e 1 ectri cal home appliances would be enforced from 1981 to 1985 but that target efficiencies would be reduced by 10 percent. Energy saving due to retrofitting of homes was assumed to be confined to s·ingle family residences and to occur between 1980 and 1985. Heating eneriD· consumption was assumed to be reduced by 4 percent in Fairbanks, 2 percent in Anchorage and between 2 and 4 percent in the Glennallen-Valdez area. Enforcement of mandatory construction or performance standar:!s for new housing was assumed in 1981 with a reduction of the heat load for new permanent home construction by 5 percento In the commercial-industrial-government sector, it was assumed by ISER that e 1 ectri city requirements for new construction ~Joul d be reduced by 5 percent between 1985 and 1990 and by 10 percent during the period 1990 to 2000. It was assumed that retrofitting measures would have no impact • .., Impacts of Recent Le9islation The National Energy Conservation Policy Act includes a variety of incen- tives and mandates fair energy conservation and alternative energy use by indiyiduals, state government and business. The new programs consist of energy audits of residential customers and public buildings, insulation and retrofitting of homes through loan and grant programs, improvement of energy efficiency of schools and hospitals, and use of solar energy. 5-10 :1 I I I I I I I I I I I c I I •• I I I .I I I ·I I I I I I I I I I I I I I I I ,.I c/' .. The Public Util'\ties Regulatory Policies Act (PURPA} of November 9, 1978, requires state public utility commissions to consider certain rate-making standards for utilities if they have sales in excess of 500 million kilowatt hours. The established standards to be considered are: • Rates to reflect cost of service; • Abolition of declining block rates; • Time-of-day rates; and • Seasonal rates. Both Chugach Electric (CEA) and Anchorage Municipal Light and Power Department (AMLPD) are affected by the provisions of PURPA regarding rate and service standards for electr·ic utilities. According to the report by the Alaska Center for--Policy Studies, the Alaska Public Utilities Commis- sion (APUC) intends to deal with the rate and load management considera- tions called for by PURPA in 1981. -Study Assumptions The programs of energy conservation and load management measures that could be implemented in addition to those included in the ISER forecast are the following: • Energy· programs provided for in the recent state energy conservation legisl(l.tion; • Load management concepts now tested by utilities, including -rate reform, to reflect incremental cost of service and load controls. These measures could decrease the growth rate of energy and winter peak projected in the ISER forecast and the forecasts used in generation plan- ning. The impa~ts would be mainly in the residential sector. The impact of state energy conservation legislation has been evaluated in a study by Energy Probe which indicated that it caul d reduce the amount of electricity needed for space heating by 47 percent. The total growth rate in electricity demand over the 1980-2010 period would drop from an average of 3. 98 percent per annum (projected by ISER in the MES-GM .-fore- cast) to 3. 49 percent per annum. Energy Probe indicated that the e lec- tri cal energy growth rate caul d be reduced even further to 2. 70 percent per annum with a conservation program more stringent than that contem- plated by the State legislature. The low forecast case assumed in development selection studies inCOl"por- ated an annual growth rate of 2.71 percent. This rate would be reduced with enforcement of energy conservation measures more intensive than those presently in the State .1 egis 1 ature. An annual growth rate of 2.1 percent was judged to be a reasonable lower 1 i mit for e 1 ectr i ca 1 demand for purposes of this study. This represents a 23 percent reduction in growth rate which is similar to the reduction developed in the Energy Probe study. 5-11 The implementaticn of load management measures would result in' an additional reduction in peak load demand. The resi'dential sector demand is the most sensitive to a. shift of load from the peak period to the offpeak period. Over the 1980-2010 period, an annual growth rate for peak load of 2.73 percent was used in the low forecast case. With load management measures such as rate reform and load controls; this growth rate could be reduced to an estimated 2.1 percent. The annual load factor for year 2010 wou1 d be increased from 62.2 ;Jercent in the 1 O\'l forecast to 64.4 in the lowest case. 5.8 -Battelle Load Forecasts As part of its study of Alaska Railbe1t Electric Energy Alternatives, Ba\:telle did extensive work in reviewing the 1980 ISER forecasts, methodoloQy, and data, and produced a new series of forecasts.. These forecasts built on the base of information and modeling established by ISER 1 s 1980 work and, with the assis- tance of ISER, developed new models for forecasting Railbelt economic acti.vity and resulting electrical energy demands. The resulting forecasts were adopted directly for use in final generation planning studies under this feasibility study. These revised forecasts included both an energy and peak capacity projection for each year of the study period (1982-2010). The projection left out portions of electrical demand which would be self-supplied, such as much of the military demand ana some of the industrial demand. In addition, these for.ecasts took into account the conservation technology and market penetration likely to take placee Details of the Battelle forecasts and methodology are available in 1 series of reports produced by Battelle in early 1982. The Battelle forecasts are based on energy sales, and have therefore been: adjusted by an addition of an estimated 8 percent for transmission losses to arrive at the supply forecast to be used in generation planning. Table ~~~1 presents the three Battelle forecasts wlli ch were prepared to bracket thf~ r?.ttge of electrical demand for the future. The Baitell~ forecasts were used in second stage generation plannin§ studies. Th: second stage studit;>s focused on the economic and financial feasibility of the se 1 ecteu Susitna project and the sens it! vity of the analyses to variation of key study assumptions. The differences between the ear 1 i er ISER forecasts used in development selection studies and the revised Battelle forecasts are not con- sidered to be significant enough to have altered the conclusions of those studies. The Railbelt generation planning studies undertaken for Susitna f:easi- bilitv assessment were therefore based on the Battelle medium fo~ecast. The high "and 1 ow Batte 11 e forecasts were used as a basis for sensiti V·ity testing. No additional information on load patterns relative to monthly and daily shift- ing of load shapes was developed in the Battelle forecasts. Thus, the histori- cal data developed to use with the 1980 ISER forecasts were also used with the Battelle forecasts. 5-12 I I I I ,I: ,. . I I I I I I ·I I I I I I I . •. 1· ... I I I I I I I I I I I I I I· I I I I TABLE 5.1:. HISTORICAL ANNUAL GROWTH RATES OF ELECTRIC UTILITY SALES ~----~~~~~--~~~~~~~~~~~~~~~~~ Anchorage and Fairbanks Period u.s. Areas 1940 -1950 8.8% 20.5~ 1950 -1960 a. 7% 15.3% 1960 -1970 7.3% 12.9% 1970 -1978 4.6% 11.7% 1970 -1973 6.7% 13.1% 1973 -1978 3.5% 10.9% 1940 -1978 7.3% 15.2% •• a s TABLE 5.2: ANNUAL GROWTH RATES IN UTILITV CUSTOMERS AND CONSUMPTION PER CUSTOMER Residential 1965 1978 Annual Growth Rate (%} Commercial 19{.5 1978 Anmuil Growth Rate (%) - ~--Gr_e_a_t~t:'. Anchorage Customers Consumption per (lhousands) Customer (MWh) 2.7 6.4 7.7 10.9 8.4 4? ·- 4.0 10.2 7.5 Greater Fairbanks Customers Consumption per (Thousands) Customer (MWh) 8.2 4.8 17.5 10.2 6.0 6·.0 \. 3 2.9 6.4 u.s. Customers Consu~;>tion per (Millions) Customer (MWh) 57.6 4.9 11 .a o.a 2.) 4.6 7.4 9.1 1.6 --.. -·-•.•. --.• -- TABLE 5.3: UTILITY SALES BY RAILBELT REGIONS Greater ~nchorage Greater F' air6anl<s Giennaiien-Vaiaez RaH6elE Total 1 1 1 1 Sale!; No.. of Sales No. of Sales No .. of Sales No. of Reg.tonal Customers Reg1onal Customers ·Regi.onal Customers Customers Year G\'lh Shar:e (Thousands) GWh Share (Thousands) GWh Share (Thousands) GWh (Thousands) 1965 369 78% 31.0 98 21~0 9.5 6 1% .6 473 41.1 1966 415 32.2 108 9.6 NA NA 523 41.8 1967 461 34.4 66 NA NA NA 527 34.4 1968 519 39.2 141. 10.8 NA NA 661 :m.o 1969 587 42.8 170 11.6 NA NA 758 54.4 '1970 684 75% 46.9 213 24% 12.6 9 1% .o 907 60.3 e 1971 797 49.5 251 13. 1 10 .9 1059 63.5 '1972 906 54.1 262 1).5 6 .4 1174 60.0 1973 1010 56.1 290 13.9 11 1.0 1311 71.0 '1974 1086 61.8 322 15.5 14 1. 3 1422 78.6 1975 1270 75% 66.1 413 24% 16.2 24 1% 1. 9 1707 84.2 •J976 1463 71.2 423 "i7.9 33 2. 2 1920 91.3 1977 '1603 81.1 447 20.0 42 2.1 2092 103 .. 2 1978 1747 79% 87.2 432 19% 20.4 38 2% 2.0 22.17 109.6 Annual Growth 12.7% 8.2% 12.1% 6.1% 13.9% 9~7% 12.6% 7.8% NOTES: (1} Includes residential and commercial users only, but: not miscellaneous users. Source.: Federal Energy Regulatory Commission, Power System Statement. NA: Not Available. 0 TABLE 5.4: RAILBEL T ELECTRICITY END-USE CONSUMPTION (GWh) Commercial-Industrial Year Residential -G01:ernment Miscellaneous 1965 214 248 9 1966 241 275 8 1967 208 241 8 1968 294 355 11 1969 339 407 12 1970 402 489 14 1971 478 555 25 1972. 542 613 17 1973 592 698 19 1974 651 749 20 1975 790 886 28 1976 879 1012 26 1977 948 1117 21 1978 1029 1156 27 Average Annual Growth 12.8% 12.6% 8.8% % of Annual Consumption 1965 45% 5)% ?G! -10 1970 44% 54% 2% 1975 46% 52% 2% 1978 .47% 52% 1% I I I I I I I I I I I I ---- Year 1980 1985 1990 1995 2000 2005 2010 Average Annual Growth Rate (%} 1980-1990 1990-2000 2000-2010 1980-2010 NOTES: TABLE 5.5: BASE CASE fORECAST (MES-GM)1 (GWh} Otiii£~ Sales to ~[.[ ~onsuminl !lectors G ennallen- Anchorage 1907 2438 2782 3564 4451 5226 6141 }.85 4.81 3.27 3.85 Fairbanks 446 669 742 949 1117 1397 1671 5.22 4.72 3.57 4.50 Valdez 37 64 75 88 102 119 140 7.32 3.12 3.22 4.54 Sales Total Utility 2390 3171 3599 4601 5730 6742 7952 4.18 4.76 3.33 4.09 Military Net Generation 334 334 334 334 334 334 334 0.0 0.0 0.0 0.0 (1) Reproduced from ISER's (_) Medium Economic Gcowth/Moderate Government Expenditure Scenario (without price induced shift to electricity)~ !lelf -Supplied Industry Net Generation 414 571 571 571 571 " 571 571 3.27 o.o o.o 1.oa- ---- -- ---------------------------- LES-Gl1 Year Bound 1980 2390 1985 2798 1990 3041 1995 3640 2000 4468 2005 4912 2010 5442 Average Annual Growth Rate (%} TABLE 5.6: SUMMARY OF RAtlBElT ELECTRICITY PROJECTIONS Utilit~ Sales to All Consumin9 Sectors (GWh) Military Net ·Generatilnn (GWh) MES--GM HES-GH 1 MES-GM with Price MES-CiM lES~GM (Base Case) Induced Shift HES-GM Bound (Base i~ase) LES-GM 2390 2390 2390 2390 2.590 JJ4 414 2921 3171 3171 3561 3707 ~:i34 414 3236 3599 3599 4282 4443 334 414 3976 4601 4617 5789 6317 334 414 5101 5730 6525 7192 8010 334 414 5617 6742 8219 9177 10596 334 414 6179 7952 10142 11736 14009 334 414 5elf-Supplied Industry Net Generation (GWh) MtS-GM MES-GM with Price (Base Case) Induced Shift HES...:Gf!tl 414 414 414. 571 571 B47 571 571 98'1 571 571 981 571 571 981 571 571 981 .571 571 981 1980-1990 2.44 3.08 4.18 4.18 6.00 6.40 o.o o.o 3.21 3.27 9~~ ·t990-2000 3.92 4.66 4.76 6.13 5.32 6.07 0.0 o.o o.o o.o o.o: 2000-2010 1.99 1 .. 94 3.33 4.51 5.02 5.75 0.0 0.0 0.0 0.0 O~Ql _1_9a_o_-_20_1_o ___ 2~.7_.8 _____ 3_._22 ______ 4_e0_9~---------4_.9_4 _________ S._4_5 ___ 6_.0_7 ______ o~·~o~----·--o~·~o~----1~-~o~a ________ ~1~.o~a ______ ~2·~-9~-~~ NOTES: Lower Bound = Estimates for LES-GL Upper Bound = Estimates for HES-GH LES = low Economic Growth MES = Medium Economic Growth HES = High Economic Growth Gl = low Government Expenditure GM = Moderate Government Expenditure GH = High Government Expenditure (1) Results generated by Ac~·es, all others by lSER. --..... ··---- ----- \ -~----~-------------·'·--·--· TABLE 5.7: SUMMARY OF RECENT PROJECTIONS OF RAILBEll ELECTRIC POWER REQUIREMENTS (GWh) Stupy Number/Source 1. ,, 2. Electric Power in Alaska 1976-1995 1nshtuta of SOc~al and Economic Research, University of Alaska, 1976. 3. 4. Upper Susitna River Pr&!ect Power Ma~ket Analyses, U.S. partment of Frlergy, Alaska Power Administration, 1979; South Central Railbelt Area, Alaska, O~per Sus~tna River Basin, Supplemen al feas~b~ht~ Reaor.f, Corps of Engineers, 197_ an Phase I Technical Memorandum: Electric .Power ~eeds Assessment, SOuth Central Alaska Water Resources Committee, 1979. 1980 low Med High 3020 3240 3550 2478 -3877 2600 -3400 2920 3155 3410 1990 •1995 2ooo 2025 low Med High low Med High low Med High Low Med U:i!.l,ljh - 5470 6480 8540 6656 8688 12576 8100 11650 18520 5415 ... 12706 8092 -t~~84 8500 -10800 10341 -17552 16000 -22500 4550 6110 8200 5672 8115 11778 7070 10940 16920 8110 17770t :$'8020 . I i I ' ... ,_ TABLE 5.a~ PERFORMANCE OF PASt P~OJECTIONS_ RAIL BELT ElECTR lC POWER Rt.Qd'ffiEf"iENTS1 Annual Growth Rate· of Percent Error4 Net Energy Between in forecast Net Energy ( GWJi). rorecagt. Year & 1980 of Growth 2 Study Yeat' of Year of ·Forecast 3 Rate to Number Publication Forecast for 1980 Forecast Actual 1980 (%) - 1 1975 1851 J240 11.9 7.3 + 63 2 1976. 2.093 2985 9.3 5.9 ... 58 J 1978 2397 3000 11.9 4.8 +· 148 4 1979 2!!69 3155 27.8 6.5 + 328 NOTES: ( 1) Net Energy figures calculated from sales plus 1 0 percent for losses ·(2) Corresponds to Table 5.7. (3) Assuming 1980 Net Energy consisting of 2390 of sales plus 10 percent: losses. (4) Indicates o\'erestimation. I I I I I ,I I I I .II . .j I II I! ill . i -I . ' I ~ I ~ I t .... -· - Year '1978 1980 1985 1990 1995 2000 2005 2010 Percent Growth/Yr. 1978-2010 NOTES: -- -l ' .. --···- / TABLE 5.9: FORECAST TOTAL GENERATION ANO PEAK LOADS-TOTAL RAILBELT REGION1 I5ER (ow·. ([ES-GRJ Z: IS£R ReiHum (RE:S-GRJ ISrR Ri 9n (RrS-GRJ Peak Peak Peak Generation Load f.eneration load Generation Load (GWh) (MW) (GWh) (MW),. (GWh) (MW) 3323 606 332.S 606 3323 606 3522 643 3522 643 4135 753 4141 757 4429 BOB 5528 995 4503 824 4922 898 6336 1146 5331. 977 6050 1105 8013 1ll56 6599 12'10 7327 1341 9598 1750 7188 1319 8471 1551 11843 2.158 7822 1435 9838 1800 14730 .2683 2.71 2.73 3.45 3.46 4.76 4.76 (1) Includes net generation from military and self-supplied industry sources. (2) All forecasts assume moderate government expenditure • . ·ol -' ·-f·.· . . ·. t Year 1980 1985 1990 1995 2000 2005 2010 TABLE 5.10: _1980 RAILBElT REGION LOAD AND ENERGY FORECASTS USED fOR GENERATION PLANNING STUDlES FOR DEVELOPMENT SELECTION L 0 A D CASE Low Plus Load Management and Low f.fedium High Conservation (LES-Gl)Z (MES-GM)J (HES-GH)4 (LES-GL Adjusted)1 Load load load MW GWh Factor MW GWh Factor MW GWh F"actor MW GWh 510 2790 62.5 510 2790 62.4 510 2790 62 . .4 510 2790 560 . 3090 62.8 580 3160 62.4 650 3570 62.6 695 3860 620 3430 63.2 640 3505 62 .. 4 735 4030 62.6 920 5090 685 3810 63.5 795 4350 62.3 945 5170 62.5 1295 712() 755 4240 63.8 950 5210 62.3 1175 6430 62.4 1670 9170 835 4690 64.1 1045 5780 62.2 1380 7530 62.3 2285 12540 'JZO 5.200 64.4 '1140 6220 62.2 1635 ·8940 62.4 2900 159)0 Load Factor 62.4 63.4 6Je 1 62 •. 8 62.,6 62.6 61 .. 7 Notes: (1) LES-GL: low economic growth/low government expenditure with load management and conser\ation. (2) LES-Gl: Low economia growth/low government.expenditure. (3) MES-GM: Medium :economic growth/moderate government expenditure. (4) HES-GH: High economic growth/hi~ government expenditiH·e. 0 u· 1 .. I I . I I . I I I I I I I ~· I I I I ., ... ··, '· ' I ' ' 1 ... i ,; .. I cr·.' . . a: I I I I I I I I I ·I I I I I ~.I. lfc ~{~:1)-' ... lABL.E 5.11: 1981 BATiELLE PNL RAILBE;LT REGION LOAD AND ENERGY F'ORECASTS USED FOR GENERATION PLAnNING STUDU::s --ECON0~11C ANALYSIS AND . SENSIT!VITY ANALYStS - t 0 A 0 CAsE Rea1.um Low H1.gh Loa a LoaCf Co ad Year MW GWh Factor MW .. GWh Factor MW GWh Factor ··- 1981 5.74 2893 57.5 568 2953 57.3 598 3053 .58.3 1985 681 3431 57 .. 8 642 3234 57.5 794 4231 60.8 1990 892 4456 57.0 802 3999 S6o9 1098 5703 59.3 1995 983 4922 57 .. 1 849 4240 ~7.0 1248 6464 59.1 2000 1084 5469 57.4 921 4641 57.4 1439 7457 59.0 c 2005 1270 6428 57.8 1066 5358 . 57.4 1769 9148 59.0 20,0 1537 7791 57.9 1245 6303 57.8 2165 11,435 60.3 Average Annual Gro"'th Rate(%) 1981-1990 5.0 4.9 3 •. 9 3.8 7.0 7.2 1990-2000 2.0 2.1 1.4 1.5 2.7 2.7 2001-2010 3.6 3.6 3.1 3.1 4.2 4 .. 4 1981-2010 3.5 3.5 2.7 2.8 4.5 4.6 I I I 'I I I I I I ·I I I I I I I I I I -~ 1500~----------~--------~~----------~ w ....1 ~ (I) >-.... -(.) -a:: .... ~ 1000~----------~~----~---+--~------~· ....1 IJJ 0~----------~------------~----------~ 1965 1970.. 1975 1980 YEAR HISTORICAL TOTAL RAILBELT UTIUTY SALES TO FINAL CUSTOMERS FfGURE 5.1 .• :1 t I I I I I I' I. ,, I I I I I I I' I I - ISP-----------~--------------------------------------------~ 17 16 LEGEND HES-GH : HIGH ECONOMIC GROWTH t HIGH GOVERNMENT EXPENDITURE HES-GM : HIGH ECONOMIC GROWTH t MODERATE GOVERNMENT EXfla.l)lTURE MES ~ GM :: MODERATE ECONOMtc GROWTH + MOOERATE GOVERNMENT EXPENI:lTURE LES ·GM : u::Ni ECONOMIC GROWTH+ MODERATE GOVERNMENT EXPENDiTURE LES-GL : ·LoW ECONCMtC GROWTH+ LOW GOVERNMENT EXPENDITURE 15P-------------------~----------------~------------------~ 1/ HES ·GH / I I I I I I / HES- 1985 1990 1995 YEAR 2000 2005 FORECAST ALTERNATIVE TOTAL RAILBELT UTILITY SALES 2010 ,, I t I I I I I I I I I I I I I I I I 16~----------------------------------------------~----------~ 15 14 13 12 II -:c LEGEND HES-GH ~ H!GH ECONOMIC GROWTH + HIGH GOVERNMENT EXPENDiTURE MES-GM -= MODERATE ECONOMIC GROWTH + MODERATE GOVERNMENT ~XPENDITURE LES .. GL :: LOW ECONOMIC GROWTH +LOW GOVERNMENT EXPENDITURE LES -GL ADJUSTED : LOW ECONOMIC GROWTH +LOW GOVERNMENT EXPENDITURE 1-LOAD MANAGEMENT AND CONSf.RVATlON \ I I I I I I I /. : I I HES-GH I I I I I I I I ~ I0~------------------4-------------------~-4~--------------~ <!) - 2 Q 9 ~ 0.:: w z w ·8 (!) >-.... u 7 -0:: 1-u ~ 6 w 4 2 I I o~--------._--------~--------~--------~--~----_.--------~ 1980 1985 1990 1995 YEAR 2000 2005 20€0 ENERGY FORECASTS USED FOR GENERATION PLANNING STUDIES ._lfPD(O ]_ FIGURE 5.3 HUB ll • t I I I f; I I I I I I I I II I, ; ., .. ' . 6 -RAILBELT SYS!Efvl AND FUTURE POWER GENERATION OPTIONS This section describes the process of assembling the information necessary to carry out the systemwide generation planning studies necessary for assessment of economic feasibility of the Susitna Project. Included is a discussio~ of the existing system characteristics, the planned Anchorage-Fairbank~ intertie, and details of various generating options including hydroelectric and thermal. Per~ formance and cost information required for the generation planning studies is presented for the hydroelectric and thermal generation options considered .. Effective planning of future electric power generation sources to meet the pro- jected needs of the Railbelt Region must address a number of concerns. Apart from the obvious goal of planning to meet projected power and energy needs of the region, careful consideration must be given to the trade-offs which will be required in satisfying those needs within the constraints of technical feasi- bility, economic necessity, acceptable environment~ impacts, and social prefer- ences. The hydroelectric potential in the Susitna River aasin is but one of the available options for meeting future Railbelt demand. If constructed, the Susitna Basin Development Plan would provide a major portion of the Railbelt Region energy needs well beyond the year 20004 The generation planning studies for the Railbelt Region which were undertaken as part of the Susitna development selection process were an essential first step in the study process. These studies formed the basis for optimization of project components as well as the economic and financial feasibility assessment for this major development. 6.1 -Basis of Study As with the load forecasts presented in Section 5, two sets of data were avail- able during the feasibility study. The initial set of data was developed in support of the development selection studies, as described in more detail in Section 8. These studies were completed in 1980 and reflected a price level estimated at January, 1981 and data available at that time. Emphasis in that study was placed on currently feasible, economic generating sources. Ot~er options, including emergency technologies of wind, solar, and bio-mass-fired generation were not considered. Also not considered were commercially unavailable technologies such as gasified coal, combined cycle plants, or· natural ga~ fuel cells. The information developed in the subsequent feasibility study was used to support generation planning efforts which compared alternative developments H1 the Susitna Basin, alternative developments at Watana and Devil Canyon, and project details such as dam height, installed capacity, tunnel diameters, and reservoir oper&ting rules. The information on non-Susitna generation options has been dealt with only in sufficient detail to develop representative performance and cost data for inclusion in the alternative Railbelt system generation scenarios. The detailed Susitna optimization studies and economic and financial feasibility and sensitivity assessments, described in Section 18 of this report, were based, to the maximum extent possible., on updated information. This information was made as consistent as possible with the Battelle Pacific Nor:thwest Laboratories data derived in the concurrent study of Railbelt alternatives. Information used in Susitna generation planning studies was thus adjusted appropriately for gen- eral consistency with Battelle data for: -Load for·ecasts; -Capital costs of alternatives; -Fuel costs and escalation; and Escalation of capital and O&M costs. In addition to this, Susitna capital costs were adjusted to reflect most recent estimates prepared unde.r Task 9. Generation planning studies were thus, in some cases, based on somewhat different basic data and assumptions from those used in the earlier development selection studies. On the other hand, a great deal of significant data is common to both evaluations: for example, the composition of the existing generation mix in the Railbelt, the status of the Intertie, data for the non-Susitna hydroelectric alternatives, and the selected non-Susitna thermal alternatives. The differences in data values used in the development selection studies are not considered to be large enough to have significantly affected the conclusions of those studies. Thus, the current Susitna feasibil- ity assessment as presented in Section 18 is also considered to be validM 6.2 -Existing System Characteristics (a) System Description The two major load centers of the Railbelt Region are the Anchorage-Cook Inlet area and the Fairbanks-Tanana Valley area (see Figure 6.1). At pre- sent, these two areas operate independently. The existing transmission system betwee~ Anchorage and Willow consists of a network of 115 kV and 138 kV lines with interconnection to Palmer. Fairbanks is primarily served by a 138-kV line from the 28-MW coal-fired plant at Healy. Communities be- tween Willow and Healy are served by local distribution. There are currently nine electric utilities (including the Alaska Power Administration) providing power and energy to the Railbelt system. Table 6.1 summarizes the total generating capacity within the Railbelt Sys- tem in 1980, based on information provided by Railbelt utilities and then reliable sources. This information has been subjected to minor adjustments compared with that used in the deve 1 oprnent select ion studies so as to main- tain consistency with Battelle alternatives study data. · Table 6.2 presents the resulting detailed listing of units currently oper- ating in the Railbelt, information' on their perform~nce characteristics, and their online and assumed retirement dates. With the exception of.t\vO hydroelectric plants, the total Railbelt instal- led capacity of 984 MW as of 1980 consists of 938 MW of thermal generation units fired by oil, gas, or coal; as summarized in Table 6.3. ··o::..-'2 · . . I I I I :I' ' I I I I I I I I a I t I I L___~---~-~---~-'--'--~--~~~~~~--......:_,~~; ·~· •·..=e-•~"=.L-'''-!'·"'-'.' '""'-"" ·=~-~,~ ....... -~··;:..:.,;• -~·....,;••'"""'·"""'-"""''..;.;,'.;,~ . ...,,..,,,._ ... , .. ,... ..... ,.~~<-~.1":. ~.,,,,..,.~.,..,, ,._,,<;,>>..< r•··~~-..,., •~• ·~•' v.,,,.;., ,;,,_,,,, -..--• '··"-' ''"'""'"'-'<• "' '*" • """'~•~"-""''~·•--- ~' I I I I· I I I I t 'I I J I •• I l I I • (b) Schedule Retirements In order to establish a retirement policy for the existing generating units, several sources were consulted, including the APA draft feasibility study guidelines, FERC guidelines, Battelle's study, and historical records. Utilities, particularly those in the Fairbanks area, were also consulted. Based on the abo.ve, the following retirement periods of opera- tion were adopted for use in this study: ~ -Large Coal-Fired Steam Turbines (> 100 MW): -Small Coal-Fired Steam Turbines ( < 100 MW): -Oil-Fired Gas Turbines: -Natura 1 Gas-Fired Gas Turbines: -Diesels: Combined Cycle Units: Conventional Hydro: 30 years 35 years 20 years 30 years 30 years 30 years 50 years Table 6.2 lists the retirement dates.for each of the current generating units based on the above retirement policy. (c) Schedule of Additions Six new projects are currently expected to be committed within the Railbelt system. The CEA is in the process of adding gas-fired combined-cycle capacity in Anchorage at a plant called Beluga No. 8. When complete, th_e total plant capacity will be 178 NW, but the plant will encompass existing Units 6 and 7. Chugach is also planning a 26.4 r~w gas turbine rehabilita- tion at Bernice Lake No. 4 in 1982. For study purposes, this plant is assumed to com~ on line in January, 1982. The COE is currently in the post-authorization planning phase for the Bradley Lake hydroelectric project located on the Kenai Peninsula. As cur- l' rently envisaged, the project includes 90 ·Mw of installed capacity and would produce an annual average energy of 350 Gwh. For study purposes~ the project is assumed to come on line in 1988. Three other units are also scheduled or have been added to the system si nee 1980. Anchorage Municipal Light and Power Department is adding a 90 NW gas turbine in 1982 called Bernice Lake No.4. Copper Valley Electric Associa- tion is operating the new 12 MW Solomon Gulch Hydroelectric Project •. Finally, the 7 mW Grant Lake hydroelectric project is undergoing planning for addition to the system in 1988 by the APA. 6.3 -Fairbanks -Anchorage Intertie Engineering studies have been undertaken for construction of an i nterti e between the Anchorage and Fairbanks systems. As presently envisaged, this connectio~n will involve a 345-kV transmission line between Willow and Healy scheduled for completion in 1984 .. The line will continually be operated at 138 kV with the capability for expansion as the loads grow in the load centers. · Based on these evaluations~ it was concluded that an interconnectt.~d system should be assumed for all the g~ner·ation planning studies outlined in this report, and that the basic intertie facilities vmuld be common to a11 generation scenarios considered. 6-3 " ' ' . ,.. .... -,, .. , ---~~ ...... , ·~ -................ < ~ ..... -"'<• ---··-"'-·• .. "''· ---.. -~ From this point, costs of transmission facilities were added to the scenarioss as necessary for each unit added. In the "with Susitna" scenarios, the costs of adding circuits tn the intertie corridor were added to the Susitna project cost~ For the non-Susitna units, transmission costs were added as follows: -No costs were added for combined-cycle or gas-turbine units, as they were assumed to have sufficient siting flexibility to be placed near the major transmission works; - A multiple coal-fired unit development in the Beluga fields was estimated to have a transmission system with equal security to that planned for Susitna, costing $220 million. This system would take power from the bus back to the existing load center; and A single coal-fired unit development on the Nenana area, using coal. mined in the Healy fields, would require a transmission system costing $117 million dollars .. With the addition of a unit in the Fairbanks area in the 1990s, no additions to the 345 kV line were considered necessary. Thus, no other transmission changes were made to the non-Susitna plans. 6.4 M Hydroelectric Options Numerous studies of hydroelectric potential in Alaska have been undertaken. These date as far back as 1947, and were performed by various agencies including the then Federal Power Commission, the COE, the USBR, the USGS and the state of Ai ask a. ll.. significant amount of the identified potential is located in the Railbelt Region, including several sites in the Susitna River Basin. 0 As discussed earlier in this section, feasibility assessment of the selected Susitna Basin Development Plan is based on comparisons of future Railbelt power generatj on seen ar ios with and without the project. An obvious 11 without Sus itn au scenario is one which includes hydroelectric developments outside the Sustina Basin. The plan formulation and selection methodology discussed in Section 1 has been applied in the development of Railbelt generation plans which include and exclude Susitna. Those plans which involve the Susitna Project a~e dis- cussed in detail in Sections 7 and 8. ·rhose plans which incorporate hydro- electric developments studied during the development selection phase other than Susitna are discussed· in this section. (a) Assessment of Hydro Alter·natives The application of the five-step methodology for selection of non-Susitna plans which incorporate hydroelectric developments is summarized 1n this section. Step 1 of this process essentially established the overall objec- tive of the exercise as the selection of an optimum Railbelt generation plan which incorporated the proposed non-Susitna hydroelectric developments for comparison with other plans. Under Step 2 of the selection process, all feasible candidate sites were identified for inclusion in the subsequent screening exercise~ A total of 91 potential sites (Figure 6.3) wer~ obtained from inventories of potential sites published in the COE National Hydropower Study and the APAd report .. Hydroelectric Alternatives for the Alaska Railbelt .. 11 • 6-4 --,1 , .. 1 t I I '"', .. ..:- :t I t I I t I I I I I I ~· i,l. I I ' I t I I t I I I •• I. It I I I I 'l I ,, (b) ~creening of Candidate Sites The screening of sites required a total of four successive iterations to reduce the number of alternatives to a manageable short list. The overall objective of this process was defined as the selection of approximately 10 sites for consideration in plan formulation> essentially on the basis of published data on the sites· and appropriately defined criteria. The first iteration in this process was based on a coarse screen in which sites which were considered technically infeasible or not economically viable were re- jected.· For this purpose, economic viability for a site was defined as energy production costs less than 50 mills per kWh, based on economic para- meters. This value was considered to be a reasonable upper limit consis- tent with Susitna Basin alternatives (See Section 8). Energy production costs were derived for each site considered, using the capital cost data published in the cited reports updated to 1980 levels, and using pub 1 i shed cost esc a 1 at ion data and an appropriate cont i ngeocy allowance. Annual costs were derived on the basis of a 3 percent cost of money, net of general inflation. Allowances for operation and maintenance costs were also included in these estimates. For this initial screening process, the reported energy yield data for each site were then used as a basisfor estimating annual energy production costs in mills per kl4h- As a result of this screen, 26 sites were rejected and the remaining 65 sites were subjected to a second iteration of screening. The additional criteria established for this screening were environmental in nature. Based on data published in the COE and APAd reports, rejection of s-Tites occurred if: -They would cause significant impacts within the boundaries of an existing National Park or a proclaimed National Monument area; or -They were located on a river in which: . Anadromous fish are known to exist; . The annual passage of fish at the site exceeds 503000; or A confluence \vith a tributary occurs upstream from the site in ~nich a major spawning or fishing area is located. As a result of this screen, 19 sites were rejected and the remaining 46 sites were subjected to a third iter at ion of economic and environme~tal screening. At this stage in the selection process, adjustments were made to capital and energy production costs for each site to take into at:count transmission 1 ine costs necessary to 1 ink each site to the Anchorage- Fairbanks intertie. A representative list of 28 sites was thus derived by judgmental elimination of the more obviously uneconomic or less environ- mentally acceptable sites" These sites were then categorized into. sizes as follows: Less than 25 MW: 5 sites; 25 MW to 100 MW: 15 ~ites; and -Greater than 100 MW: 8 sites. .6-5 .. l~"""'""'-·..._·'~>··--,.• ,., , ·• "~ --', • .(:·_,.. __ ,. '..c o·~n . ., .• ~ _;_,_, ,..,""'f_f_""."''"'•"'S"":k'·"'J..•· .· :,..,, .. ,,.:-,.. ... ;"" •L , .. ;.: •.. '''""'$ --~ .. _ . ....._,. .,.,.;,_ .. ~<T'Q("'" ,,A ,_,., ~ ••.. ,. .. •· ~' ''" •'"""'·'"~ "£· "" o' ' .•.-.>< •. , ""9'' --·~.,."·""''·~ ,_ ? . .., _._ . .,.@ f'') """'f'zj'\ .... -.,..~ ~· . ..,. ,,.:f.• • .::.~. _,.:,,.,, ..... ~ ~ , ... '., ... ,. ... ,.,.. ·~·-_,..__, ·~.:.. -"·h·· , .• ...,,~., .... ..-....,.,~. ''-z""•· ·/;;yol•~· ·>H~ ... ·~~;._ ~; ., .. ~,., ··u""-l~ .. -"--..'''-•· '" '''·""t·"~~~ I ~~~~~~~~ih e~~~ r~~;:~t:Jr:~~e~:~~e~~e~a~e~!~:~edf~ ~h~h!~~ 1 ~a~~~~ ~~t~!~~~ •t· .. · .. were utilized: -Impact on big game; -~. -Impact on agricultural potential; Impact on waterfowl, rapt or s, and endangered species, -Intpact on anadromous fish; J Restricted land uses; · · -Impact on wilderness areas; ~, -Impact on cultural, recreational, and scientific resources; and -Impact generated by access. ·:1 The above environmental ranking criteria were assigned numerical weights, and scale ratings for each site and each criterion were developed using t available data. Total scores \vere then calcula~ed for each site by summing the products of the weight and scale ratings. This process a 11 owed the number of sites to be reduced to the ten sites ~ listed in Table 6.4. , (c) Plan Formulation and Evaluation In Step 4 of the plan selection process, the ten sites shortlisted under Step 3 were further refined as a basis for formu,l at ion of Rai 1 belt genera- tion plans. Engineering sketch-type layouts \vere produced for each of the sites, and-quantities and capital costs were evaluated. These costs, listed in Table 6.4, incorporate a 20 percent allowance for contingencies and 10 percent for engineering and owner's administration. A total of five plans were formulated incorporating various combinations of these sites as input into the Step 5 evaluations. Power and energy values for each of the developments were reevaluated in Step 5 utilizing monthly streamflmv and a computer reservoir simulation model. The results of these calculations are summarized in Table 6.4. The essential objective of Step 5 was established as the derivation of the optimurn~plan for the future Railbelt generation incorporating non-Susitna hydro generation as well as required thermal generation. The methodology used in evaluation of alternative generation scenarios for the Railbelt is discussed in detail in Section 8. The criteria on which the preferred plan was finally selected in these activities were least present-worth cost based on economic parameters for development selection established in Section 8 .• The selected potential non-Susitna Basin hydro developments (Table 6.4) wer·e ranked in terms of their economic cost of energy. They were then in- troduced into the all-thermal generating scenario during the planning an- alyses (see Section 6.5)~ in groups of two c.r three. The most economic schemes were introduced first and were followed by the less economic schemes. 6-6 I I ~""""'" I I I ' I I ' " t t I .I I 'I I I I t I I I I I I ... I ' I I ,, ,I It The results of these analyses are summarized in Table 6.5 and illustrate that a minimum total system cost of $7040 mi11ion can be achieved by the introduction of the Chakachamna! Keetna, and Snow projects (See also Figure 6.4). Note that further studies of the Chakachamna project were initiated in mid-1981 by Bechtel under contract to the APA. This study is producing costs and project concepts different from the ones presented here. Additional sites such as Strandl ine, Allison Creek, and Talkeetna-2 can also be introduced without significantly changing the economics, and would be beneficial in terms of displacing non-renewable energy resource consump- tion. 6.5 -Thermal Options -Development Selection As discussed earlier in this section, the major portion of generating capability in the Railbelt is currently thermal, principally natural gas with some coal and oil-fired installations. There is no doubt that the future electrfc energy de- mand in the Railbelt would te,~:-nically be satisfied by an all-thermal generation mix. In the following paragYJpns, an outline is presented of studies undertaken to determine an appropriate all-thermal generation scenario for comparison \'lith other scenarios in Section 8. These comparisons were used in selecting the Susitna d_.evelopment and in establishing preliminary economic feasibility~ Information developed during later studies by Battelle and Acres used for-eco- nomic analysis is presented in Section 6.5. {a) Assessment of Thermal Alternatives > The plan formulation and selection methodology discussed in Section 1 has been adopted in d modified form to develop the necessary all-thermal gener- ation plans (see Figure 6.5). The overall objective established in Step l is the selection of an optimum all-thermal Railbelt generation plan for camp ari son \"i th other p 1 ans. In Step 2 of the selection process, consideration was given to gas, coal, and oi 1-fi red generation sources only from the standpoint of technical and economic feasibility. The broa.der perspectives of other alternative resources and the relevant environmental, social, and other issues involved are being_addressed in the Battelle alternatives study. This being the case, the Step 3 screening process was therefore considered unnecessary in this study, and emphasis was placed on selection of unit sizes appropriate for inc 1 usi on in the generation p 1 anni ng ex ere i se. Thus, for study purposes the following types of thermal power generation units were considered: -Coal-fired steam; -Gas-fired combined-cycle; -Gas-fired gas turbine; and -o·i ese 1. ·ro formulate plans incorporating these alternatives it was nBcessary to develop capital cost and fuel cost data for these units and other related operational characteristics. $-7 " (b) Coal~F1red Steam Aside from the military power plant at Fort Wainwright and the self- supplied generation at th.e University of A 1 ask a, there are currently two coal~fired ste~n plants in operation in the Railbelt (see Table 6.1). These plants ar·.: small in comparison with new units under consideration in the lower 48 states and in Alaska. (i) Capital Costs Based on the general magnitude of the Railbelt load requirements, three coal-fired unit sizes were chosen for potential capacity addi- tions: 100, 250, and 500 MWo All.new coal units were estimated to have an average heat rate of 10,500 Btu/kWh and involve an average construction period of five to six years. Capita 1 costs and operat- ing parameters are defined for coal and other thermal generating plants in Table 6.6. These costs include a 16 percent contingency, a 10 percent allowance for construction facilities and utilities, and 12 percent for engineering and owner's administration. The costs were developed using published data for the lm·1er 48 states and appropriate Alaska scaling factors based on studies conducted by Battelle. It is unlikely that a 500-MW plant will be proposed in the Fairbanks region because forecasted demand there is insufficient to justify placing this much capacity online at one time. There- fore, costs for such a plant at Fairbanks are not included. To satisfy the national New Performance Standards, the capital costs . incorporate provision for installation of flue gas desulfurization for sulphur control, highly efficient combustion technology for con- trol of nitrogen acids, and baghouses for par-:iculate removal~ ( i i ) F u e 1 cost s The total estimated coal reserves in Alaska are shown in Table 6.7. Projected opportunity costs for Alaskan coal range from $1.00 to $1.33 per million Btu. A cost of $1.15 was selected as the base coal cost for generation planning (see Table 6.8). The market price for coal is currently within the same general cost range as the indicated opportunity cost. Real growth rates in coal costs (excluding general price inflation) are based on fuel escalation rates developed by the Department of Energy (DOE) in the mid-term Energy Forecasting System for DOE Region 10 which includes the states of Alaska, \vashington, Oregon, ·and Idaho. Specif1ed price escalation rates pertaining to the industrial sector were selected to reflect the bulk purchasing advantage of utilities more accurately than equivalent rates pertaining to the commercial and residential sectors. A composite annual escalation rate of 2.93 percent has been computed for the period 1980 to 1995 from the five yearly v~lues given by the DOE. This composite rate has been assumed to apply to the 1995-2005 period as suggested by the DOE. Beyond 2005, zero rea_l growth in the coal price is assumed. 6-8 I I I I I t I '- I I ..... .• " I I ..... I ' I t a I t I I I .. I I t t I:' I I I •• "' .... I ' t I a I t. (c) (d) ----~c--.~~.,------l (iii) Other Performance Characteri sties Annual operation and maintenance costs and representative forced outage rates are shown in Table 6 .. 6 . fombined Cycle A combined cycle plant is one in which electricity is generated partly in a _gas turbine and partly in a steam turbine eye 1 e. Combined eye 1 e p 1 ants achieve higher efficiencies than conventional gas turb1nes. There are two combined cycle plants in Alaska at present. One is operational and the other is under construction (see Table 6.1). The plant under construction is the Beluga #9 un~t owned by Chugach Electric Association (CEA). A 60-MW steam turbine wi 11 be added to the system sometime. in 1982. ( i) Capita 1 Costs A new combined cycle p 1 ant unit size of 250-MW capacity was con- sidered to be representative of future additions to generating cap- ability in the Anchorage area. This is based on economic sizing for plants in the lower 48 states and projected load increases in the Rai lbelt. A heat rate of 8,500 Btu/kWh was adopted based on techni- cal publications issued by the Electric Power Research Institute (EPRI). The capital cost was estimated using the same basis and data sources as for the coal-fired steam plants and is listed in Table 6.6 .. (ii) Fuel Costs . The combined cycle facilities would burn only gas with the opportun- ity value ranging from $1.08 to $2.92 per million Btu. A gas cost of $2.00 was chosen to reflect the equitable value of gas in Anchor- age, assuming development of the export market. Currently, the locaJ incremental gas market price is about half of this amount due to the relatively light local demands and limited facilities fo'r export. Using an approach similar to that used for coal costs, a real annual growth rate in gas costs of 3.98 percent was obtained from the DOE studies fore 1980 to 2005. Zero percent was assumed thereafter ... (iii) Other Performance Characteristics Annual operation and maintenance costs, along with a representative forcep outage rate, are given in Table 6.6. Gas-Turbine Gas turbines are by far the main source of. thermal power generating resources in the Railbelt area at present. There are 470 MW of installed gas turbines operating on natural gas in the Anchorage area and approxi- mately 168 MW of oi 1-fired gas turbines supplying the Fairbanks area (see Table 6.1). Their low initial cost, simplicity of construction and 6-9 j and operation, and relatively short implementation lead time have made them· attractive as a Railbelt generating alternative. The extremely low-cost contract gas in the Anchorage area also has made this type of generating facility cost~effective for the Anchorage load center. (i) Capital Costs A unit size of 75 MW was considered to be representative of a modern gas turbine plant addit1on in the Railbelt region. However, the possibility of installing gas turbine units at Beluga was not con- sidered, since the Beluga development is at this time primarily being considered for coal. Gas turbine plants tan be built over a two-year construct1on period and have an average heat rate of approximately 12,000 Btu/kWh. The capital cost was evaluated using the same data source as for the coalfired plants and incorporates a 10 percent allowance for con- struction facilities and 14 percent for engineering ~nd owner's administration. This cost includes provision for wet control of air emissions .. (ii) Fue1 Costs Gas turbine units can be operated on oil as well as natural gas~ The opportunity value and market cost for oil are considered to be equal, at $4.00 per million Btu. Real annual growth rates in oil costs were developed as described above and amounted to 3.58 per·cent for the 1980-2005 period and zero percent thereafter. (iii) Other Performance Characteristics Annual operation and maintenance costs and forced outage rates are shown in Table 6.6. (e) Diesel Power Generation Most diesel plants in the Rai.lbelt today are on standby status or are oper·- ated only for peak load service. Nearly all the continuous duty units wer.e retired in the past several years because of high fuel prices. About 65 Mt~ of diesel plant capacity is currently available. (i) Capital Costs . ~ The high cost of diesel fuel and low capital cost makes new diesel plants most effective for emergency use or in remote areas where sma 11 loads exist. A unit size of 10 MW was se 1 ected as appropriate for this type of facility. The capital cost \'/as derived from the s arne source as given in Tab 1 e 6. 6 and includes pro vision for a fuel injection system to minimize air pollution. (ii) Fuel Costs Diesel fuel costs and growth rates are the same as oi 1 costs for gas turbines. · 6-10 I I I .,. I I t t I I _,.. I I 'I '· ~ .... I ' t ,, ' I .I I I I '· t I ... t t. ' I a I I ' I t I I I I 1~· •. (iii) Other Performance Characteristics Annual operation and maintenance and the forced outage rate is given i n Tab 1 e 6 • 6 . (f) Plan Formulation and Evaluation The six candidate unit types and sizes developed under Step 2 were used to formulate plans for meeting future Rail belt power generation requirements in Step 4~ The objective of this exercise was defined as the formulation of appropriate plans for meeting the project Railbelt demand on the basis of economic prefer~nces . Two different cases of natural gas consumption policy were considered in formulating plans. The first, called the 11 renewal 11 policy, allowed for the renewal of natural gas turbines at the end of their economic lives, antici- pating the possible exemptions that utilities may obtain from the Fuel Use Act (FUA). The secor.d policy, called the 11 no renewals" pol icy, assumed that the utilities would not be allowed to reconstruct plants as they are retired and that they would only be allowed to construct new plants with not more than 1,500 hours of ann~al operation. In the subsequent Step 5 evaluation of the two basic plans, the OGP5 gener- ation planning model was utilized to develop a least cost scenario incor- porating the necessary coal, oil, and gas-fired generating units. The results for the very low, low, medium, and high load forecasts are sunmar- ized in Table 6.5. They indicate that for the medium forecast the total system present worth cost is sli~htly higher than $8,100 million. As illustrated by the results displayed in Table 6.5, these two policies have very similar economic impacts. The difference in present-worth costs for the medium forecast amounts to only $20 million~. For purposes of this study, therefore, it is assumed that the 11 no renewal su pol icy is more appropriate and is used to be representative of the all-therma·l gener·ation scenario. Figure 6.6 illustrates this all-thermal generating scenario graphically. These results were used as a comparison for de.velopment sel- ection as described in Section 8. 6.6 -Thermal Options -Economic Analysis During the final stage of study, a revised set of data was available for-the selected Susitna project analysis. Much of these data was taken directly from the Battelle Pacific Northwest Laboratories independent Railbelt Alternatives study. The findings of this study are reasonably consistent with the findings of the preliminary studies pre~ented in Section 6.4. The information presented in this section is in support of the non-Susitna option presented in Section 6.6. As a result of the Battelle study, it was found that in their base case, the most 1 ikely thermal generating opportunities would be coal-fired steam electric plants, natural gas-fired combined-cycle plants, and gas-fired combustion turbines. In addition, there are several hydropower plants which would be possible. 6-11 {a) Coal-Fired Steam Plants A detailed cost study was done by Ebasco Services Incorporated as part of Battelle's Alternative study. The report found that it was feasible to site a plant at either the undeveloped Beluga field or near Nenana, using Healy field coal. The study produced costs and operating characteristics for both plants. Unit size was set at 200 MW. Details of the units are listed in Table 6.6. It was found that, rather than develop solely at one field in the non- Susitna case, development would be likely to take place in both fields. Thus, one unit would be developed near Nenana to service the Fairbanks load center, with other units placed in the Beluga fields. Fuel costs based on long-term opportunity values were set at $1.43/MM Btu for Beluga field coal and $1.75/MM Btu for Healy coal to be used at Nenana. Rea 1 escalation on these v a 1 ues was estimated as fo 11 ows: Beluga/Coal Healy Coal at Nenana 1982-2000 2.6% 2.3% 2001-2010 1.2% 1.1% Uetails of the fuel cost information are included in Section 16 of this report. (b) Combined Cycle and 6as Turbines The Battelle study also produced a cost estimate for combined cycle plants which would be located near the Railbelt gas reserves near Cook Inlet. The combined cycle plant would be similar to that envisaged by the pre1iminary Acres study, but would have a heat rate of 8,000 Btu/kWh (as compared to 8,500 Btu/kWh). The estimated capital costs were si9nificantly higher. . Gas turbines, like combined-cycle plants, had higher costs in the Battelle study than the Acres study, but lower heat rates (10,000 as compared to 10,500 Btu/kWh). 6.7 -Without Susitna Plan In order to analyze the economics of developing the Susitna project, it is nec- _essary to analyze the costs of meeting the projected Alaska Railbelt lead fore- cast with and 'tJithout the project. Thus, a plan using the identified components in Section 6.5 was developed. The basic tool used in identifying this plan was a compute~ized generation planning model~ Optimized Generation Planning (OGP), Version 5. The model simulates production costs of meeting electrical demand~ given inputs of available generating resources, costs of fuel, characteristics of plants, and potential new plants. Details on the model are presented in Appendix A. · Using the system model, a base case 11 without Susitna" plan was structured based on middle range projections. The-base case input to the model included: 6-12 ~a ' '>' . I 'I "'::~. I I .. t ,, ·I I ' I .I ' I t I t I ''"'., .. t I . ( ' ' ' I · ... t ,, ' I a· I ' 1 I I t a t· I -Battelle's middle range forecast from Section 5.6; -Fuel cost ~s specified in Section 18.1; -Coal:fired steam and gas-fired combined-cycle and combustion turb1ne units as future additions to the system; -Casts and characteristics of future additions as specified in Section 6.5; -The existing system as specified in Section 6.1 and scheduled commitments of Table 6.3; -Middle range fuel ·escalation as specified in Section 18.1; -Economic parameters of three percent interest and zero per' cent g~nera l i nfl a- !; tion; -Real escalation on operation and maintenance and capital costs at a rate of 1.8 percent to 1992 and 2 percent thereafter; and -Generation system reliability set to a loss of Joad probability of one day in ten years. This is a probabilistic measure of the inability of the gener~eting system to meet projected load. One day in ten years is a value generally accepted in the industry for V planning genera~ion systems. The model was initially to be operated for a period from 1982-2000. It was found that, under the medium load forecast, the critical period for capacity addition to the system would be in the winter of 1992-1993. Unti 1 that time, the existing system~ given the additions of the planned intertie and the planned units, appear to be sufficient to meet Railbelt demands. Given this information, the period of plan development using the model was set as 1993-2010. • The following plan was established as the non-Susitna Railbelt base plan: Existing System as of January, 1993: Remainder of Existing System Plus Committed Additions: 1190 MW Coal-fired steam: 59 MW 452 MW 140 MW 67 MW 317 MW 155 MW Natural gas GT: Oi 1 GT:. Di ese 1: Natural gas CC: Hydropower: System additions: 1993: 1994: 1996: 1997: 1998: 2001: 2003: 2004: 2005: 2(106: 2007: 2009: Tot a 1 system additions: First 200 MW coal-fired plan at Beluga field Second 200 MW coal-fired plant at Beluga field 200 MW coal-fired plant near Nenana using Healy coal 70 MW gas-fired gas turbine 70 MW gas-fired gas turbine 70 MW gas-fired gas turbine 70 MW gas-fired gas turbine 70 MW gas-fired gas turbine Two 70 MW gas-fired gas turbines One 70 MW gas-fired gas turbine Third 200 MW coal-fired unit at Beluga One 70 MW gas-fired gas turbine 800 MW coal-fired steam electric plants 630 MW gas-fired combustion turbines 6-13 '· System as of 2010 (accountjng for retirements and additions): Coa 1-·fi red steam: Natw~al gas GT: Oi 1 GT: Di ese 1: Natural gas CC: Hydropower: TOTAL 813 MW 746 MW 0 MW 6 MW 317 MW 155 MW 2037 MW The system costs attributab-l-e-to this plan are discussed·in Section 18.2. There is one pa.rticularly important assumption underlying the plan. The costs associ- ated with the Beluga development are based on the opening of that coal field for comme~ci a 1 deve 1 opment'" That deve 1 opment is not a certainty now and is somewhat beyond the contra 1 of the state, si nee the rights are in the hands of pr·i vate interests. Even if the seam is mined for export, there may be some environmen- tal problems to overcome. The greatest problem will be the availability of cooling water for the units. This problem would. be particular-ly severe with the development of several units. The problem could be solved in the 11 Worst 11 case by using the sea water from Cook Inlet as cooling water. This solution would add significantly to project costs. Two alternatives which Battelle included in their base plan which have not been included in this plan are the Chakachamna and Allison Creek hydroelectric plants. The Chakachamna plant is currently the subject of a feasibility study by the APA. The current plan would develop a 330 MW plant at a cost of $1.45 b1llion at January, 1982 price levels. The plant would produce nearly 1500 GWh on an average annual basis. Due to some current questions regarding the feasibility of the Chakachamna plant, it has not been included in the non-Susitna plan. It has been checked~ however, on the sensitivity analysis .. presented in Section 16.2. · The Allison Creek hydroelectric project \tJas included on the non-Susitna base plan by Battelle. It has not been included in this base plan due to its high costs, $125/MWh (1981 dollars). 6-14 i i . -,.,-·.--<~.~~ j < J l ' ' ' ••• ~.,. ~· t t ' I I I I ~ I I ' t t t I t I t t I t ' t I a I ,. 'I I I I t I ' TABLE 6.1: 10TAL GENERATING CAPACITY WllHIN THE RAILBELI SYSTEM Abbreviations AMLPD CEA GVEA FMUS CVEA MEA HEA SES A PAd U of A 10TAL Railbelt Utility Anchorage Municipal Light & Power Department Chugach Electric Association Golden Valley Electric Association Fairbanks ~Jnicipal Utility System Copper Valley Electric Association Matanuska Electric Association Homer Electric Association Seward Electric System Alaska Power Administration University of Alaska (1) Installed capacity as of 1980 at 0°F Installed Capacity 221.6 395.1 221.6 68.5 19.6 0.9 2.6 5.5 30.5 18.6 984.0 TABLE:;......;;.6•..;..;2;;,.;.:___.;G;;;;;E.;..;;NE;;;.;.R...;..;A.:...T;;.;..IN.;.;;G...;..;U;;;.;.N.;.;;l..;...;TS;.....;.:.W.;;;.;IT;.;.;H~lN;.;.._;.T.;..;;HE;;;.....;..;R.;.;.AI;;;.;;l~B.;;;.;EL;;.;T_-_;1:.;..9,;;.;;::80, Ra1lbelt Stat1on Unit On it InstallaEion Heat Rate Installed Utilit~ Name No. T~ee Year (Btu/kWh) Caeacit~ (MW) Fuel T~ee Retirement Y~r Anchorage Municipal AMLPO 1 GT 1962 14,000 16.3 NG '1992 Light & Powet· AMLPD 2 GT 1964 14,000 16.3 NG 1994 Department AMLPD 3 GT 1968 14,000 18.0 NG 1998 Af.iLPO 4 GT 1972 12,000 32.0 NG 2002 (AMLPO) G.M. Sullivan 5,6,7 cc '1979 8,500 139.0 NG 2011 Chugach Beluga 1 GT 1968 '15 ,ooo 16.1 NG 1998 Electric Beluga 2 GT 1968 15,000 16.1 NG '1998 Association (CEA) Seluga 3 GT 1973 10,000 53.0 NG 200J Beluga .s Gf 1975 15,000 58.0 NG 2005 Beluga 6 GT 1976 15,000 68.0 NG 20'12 Beluga 7 GT 1977 15,000 68.0 NG 2012 Bernice lake 1 GT 1963 23,440 8.6 N£; '1993 2 GT 1972 23,440 18.9 NG 2002 3 GT 1978 23,440 26.4 NG 2008 International Station 1 Gf .l96l• 40,000 14.0 NG 1994 2 GT 1965 --* 14.0 NG 1995 3 GT 1970 _..;.* 18.0 NG 2000 Cappel' Lake •• HY 1961 --* 16.0 2011 Golden Valley Healy 1 sr 1967 11 ,BOB 25.0 Coal 2002 Electric 2 lC 1967 14,000 2.8 Oil 1997 Association North Pole 1 GT 1976 n,ooo 65 .. 0 Oil 1996 (GVEA) 2 GT 1977 13,500 65.0 Oil 1997 Zehander 1 GT 1971 14,500 18.4 Oil 1991 2 GT 197.2 14,500 17.4 Oil 1992 3 Gf 1975 14,900 3.5 Oil 1995 4 GT 1975 14,900 3.5 Oil 1995 5 IC 1965 14,000 3.5 Oil 1995 6 IC 1965 14,000 3.5 on 1995 7 IC '1965 14,000 3.5 Oil 1995 8 lC '1965 14,000 3.5 Oil 1995 9 IC ')965 14,000 3.5 Oil 1995 10 IC 1965 14,000 3.5 Oil 1995 Fairbanks Chen a 1 Sf 1954 14,000 5.0 Coal '1989 Municipal 2 ST 1952 14,000 2.5 Coal. 1987 Utility 3 Sf 1952 14,000 1.5 Coal 1987 System (fMUS) 4 BT '1963 16,500 7.0 ·Oil 1993 5 ST 1970 14,500 21.0 Coal 2005 6 GT •J976 12,490 23.1 Oil 1997 FMUS 1 lC ·t967 11,000 2.8 Oil 1997 2 IC 1968 11,000 2.8 Oil 1998 3 rc 1968 11,000 2.8 Oil 1998 - ---------~-~---~------ fABLE 6.2 (Continued) Railbelt Utility Homer Electric Association (HEA) University of Alaska (U of A) Copper Valley Electric Association (CVEA) Matanuska Elec. Association (MEA) Se\'fard Electric System (SES) Alaska Power Administration (APAd) TOTAL Notes: Gr : Gas turbine CC = Combined cycle SEation Name Homer- Kenai Pt. Graham Seldovia University University University University University CVEA CVEA CVEA CVEA CVEA CVEA CVEA CVEA Talkeetna SES Eklutna HY = Conventional hydro IC = Internal combustion Sf = Steam turbine NG = Natural gas NA = Not available Unit Unit No. Type 1 IC 1 IC 1 tC 2 IC 3 IC 1 ST 2 ST 3 ST 1 lC 2 lC 1-3 lC 4-5 IC 6-7 IC 1-3 IC 4 IC 5 IC 6 lC 7 GT 1 IC 1 .) IC 2 IC 3 IC HY ... Installation Heat Rate Installed Year (Btu/kWh) Capacity (~1W) 1979 15,000 0.9 1971 15,000 0.2 1952 15,000 0.3 1964 15p000 0.6 'i970 15,000 0.6 1980 12,000 1.5 1980 12,000 ·t. 5 1980 12,000 10.0 1980 10,500 2. a 1980 10,500 2.8 1963 10,500 1. 2 1966 10,500 2.4 1976 10,.500 5.2 1967 '10,500 1. a 1972 10,500 1. 9 1975 10,500 1.0 '1975 10,500 2.6 '1976 14,000 3.5 '1967 ·tstooo 0.9 ·t965 15,000 ·1. 5 1965 15,000 1.5 1965 15,000 2.5 1955 30.0 984.0 *This value judged to be unrealistic foL' lat<ge range planning and therefore is adjusted to 15,000 for generation planning studies. Fuel T~pe Oil Oil Oil Oil Oil Coal Coal Coal Oil Oil Oil Oil on on on Oil Oil Oil Oil Oil Oil Oil ., , ...... _ -~ Retirement YLU'tir 2009 2001 1982 1994 2000 2015 2015 2015 2011 2011 1993 1996 2006 1997 ·2002 2005 2005 1996 1997 1995 1995 1995 2005 TABLE 6.3: SCHEDULE OF PLANNED UTILITY ADDITIONS (1980-1988) Utility Unit Tyee MW Avg. Energy Year (GWh) CVEA Solomon Sulch HY 12 1981 55 CEA Bernice Lake 114 GT 26.4 1982 AMLPD AMLPD fiB GT 90.0 1982 CEA Beluga 116,7,8 cc 42* 1982 COE Bradley lake Hydro 90.0 1988 APA Grant take H\ldro 7.0 1988 33 TOTAL 267.4 * New Unit No. 8 ~ill encompass Units 6 and 7, each rated at 68 M\~. Total new station capacity will be 178 MW. ,, ,, I ' I ...,_ ' t t t ..../ t. t ,, '" t ·I I I t t I t t I I ' ,, ,, t ' -~ ~ t I ,, I· "-~ t I ·a t ' TABLE 6 .. 4: OPERATING AND ECONOMIC PARAMETERS FOR SELECTED HYDROELECTRIC PLANTS Max. Average (1981 $) Gross Installed Annual Plant CapibJtl Head Capacity Ener}y Factor Co5~ No. Site River Ft. 0·1\'1) (Gwh (%) ($10 ) 1 Snow Snow 690 so 220 50 255 2 Bruskasna Nenana 235 30 '140 53 238 3 Keetna Talkeetna 330 100 395 45 463 4 Cache Talkeetna 310 50 220 51 564 5 Browne Nenana 195 100 410 47 625 6 Talkeetna-2 Talkeetna 350 so . 215 50 500 7 Hicks Matanuska 275 60 245 46 529 8 Chakachamna3 Chakachatna 945 500 1925 44 1480 9 Allison Allison Creek 1270 8 33 47 54 10 Strand line L-•~-a"c Beluga 810 20 85 49 126 Notes: (1) Including engineering and owner's. administrative costs but excluding AFOC. (2) Including IDC, Insurance, Amortization, and Operation and Maintenance Costs. (3) An indepedent study by Becht~l has proposed an installed capacity of 330 MW, 1500 GWh annually at a cost of $1,405 million (1982 dollars), including !DC. Economic2 .• Cost of Energy ($/1000 Khh) 45 113 73 100 59 90. 84 30 125 115 TABLE 6 • .S: RESULTS Of ECONOMIC ANALYSES Of ALTERNATIVE GENERATION SCENARIOS Installed Capacity (HWJ by Total S~·stem r otal£ "System Categor~ in 2010 Installed Pres.anft Worth Generation Scenario OGP5 Run Tfiermai Rxaro Capacity in Cost .... -TXEe -DescrieEion load Forecast la. No. Coal Gas Oii 2010 {M\~) ($106~) All Thermal No Renewals Very Low 1 LBT7 500 426 90 144 1160 49~ No Renewals Low L7E1 700 300 40 144 1305 592Jl] With Renewals Low L2C7 600 657 30 •)44 1431 59:Jjfj No Rene1'1als Medium LM£1 9.00 801 50 144 1895 sum With .Renewals Medium LMEJ 900 807 40 144 1891 attm No Renewals High L7fJ 2000 1176 50 144 3370 1352!il With Renewals High L2E9 2000 576 130 144 3306 136Jm No Renewals Probabilistic l0f3 1100 1176 ·fOo 144 3120 832m Thermal Plus No Renewals Plus: Medium L7\~1 600 576 70 744 1990 ,, 708~ Alternative Chakachamna (500)2-1993 Hydro Keetna ('I00)-1997 No Renewa.ls Plus: Medium Lfl7 700 501 10 894 2005 704Ql t:hakachamna (500)-1993 Keetna (100)-1997 Snow (50) -2002 No Renewals Plus: Medium LWP7 500 576 60 822 1958 706/tt Chakachamna (500)-1993 Keetna (100)-1996 Strandline (20), Allison Creek (8), Snow {50)-1998 ";}No Renewals Plus: " Medium LXf1 700 ll26 30 822 1978 704:t Chakachamna (500)-1993 Keetna ('J00)-1996 Strandline (20), Allison Creek (B), Snow (50)-2002 No Renewals Plus: Medium l403 500 576 30 922 2028 1oaa Chakachamna (500)-1993 Keetna (100)-1996 Snow (50), Cache (SO), Allison Creek (B), Talkeetna-2 (50), Strandline (20)-2002 Notes: (1) Incorporating load management and conservation. (2) Installed capacity. ..... ... ........ ·---- --• ...... • ••• ••• TABLE 6.6: SUMMARY OF rHERMAL GENERAHNG RESOURCE PLANT PARAMETERS USED IN DEVELOPMENT SELECTION STUDIES -JANUARY 1981 PRICE LEVEL PD~~r Pi'P£' ~01\[-F IRE:[) Sttru;l coAsmto CAs Parameter CYCLE TURBINE DIESEL .,') 500 t~W 250 MW 100 MW 250 MW 75 MW 10 MW Heat Rate (Btu/kWh) 10,500 10,500 10,500 8,500 12,000 11,500 O&M Costs Fixed O&M ($/yr/kW) 0.50 1.05. 15 30 2.7~ 2.75 0.50 Variable O&M ($/MWH) 1.40 1.80 2.20 0.30 0.30 5.00 Outa9es Planned Outages (%) 11 1"1 11 14 11 1 forced Outages (%) 5 5 5 6 3.8 5 Construction Period (yrs) 6 6 5 3 2 1 Start-up Time (yrs) 6 6 6 4 4 1 Total Calital Cost ($ mil ion) Railbelt: 175 26 7.7 Beluga: 1,130 630 290 Unit Ca~ital Cost ($/kW} 1 Railbeit: 728 250 778 Beluga: 2473 2744 3102 Notes: (1} Including AFOC at .0 percent escalation and 3 percent interest. TABLE 6.7: ALASKAN FUEL RESERVES Reserve ., Heating Approximate Value field Reserve Btu/lb. Buluga 2400 7200 -8900 Nenana 2000 7500 -9400 Coal (million tons) Kenai 300 6500 -8500 Matanuska 100 10300 -14000 North Slope 29000 plus Coal< Inlet 4200 plus Gas (billion cubic feet) Oil (billion cubic feet) North Slope 8400 plus Cook Inlet 200 TABt.:E 6.8: fUEL COSTS AND ESCALATION RATES SELECTED fOR GENERATION PLANNING STUDIES Parameter Economic Cost -$/Hillion BTU Annual Escalation Rate -% Per~od: 1980 -20o5 2006 -2010 -Natural Gas 2.00 3.98 0 Fuel T;tpe Coal 1.15 2.93 0 oil 4.00 3.58 0 I t ' I f ' ' I ' t t I I· I ' I t· t I I t I I I ' ' t t t I I I t t ·I t • • .' I LEGEND \I PROPOSED DAM SITES ----PROPOSED IM KV UNE ---EXISTING. LINES LOCATION MAP FIGURE · 6.1 ----~-----·---·---- SITE SELECTION \ ·PREVIOUS STUDIES FORMULATION OF CRITERIA ECONOMICS ENVIRONMENTAL 4 ITERATIONS ENGENEERING LAYOUTS A NO · COST STUOIES OBJECTIVE ECONOMICS -CH, K -CH, K,S DATA ON DiFFERENT THERMAL GENERATING SOURCES COMPUTER MODELS TO EVALUATE -POWER AND ENERGY YIELDS -SYSTEM WIDE ECONOMICS CRITERIA ECONOMICS CH,K,S a THERMA\..., LEGEND -CH, K,S,SL,AC -CH, K,S,SL 1 AC -CH, K, S ~SL,AC,CA, T-2 ---~ STEP NUMBER IN STANDARD PROCESS ( APPENDlX A) I I I ,, t ' I I t I I I I t I I I t I t. STRANCUNE L. 2.. LOWER BEL1JGA 3 • LOWER LAKE CR. 4 • ALLISON CR. 5 • CRESCENT LAI<E 2 6, GRANT LAKE 7 • McCUJRE BAY S, UPP~ Nt::L.L.IE >JUAN 9. POWER CREEK 10. SILVS. LAKE II • SOLOf!tON GULCH .12. lUS.TUMENA G 2S•IQOtKW 13. WHtSI<ERS 14. COAL 15 • CHULITNA 16, OliiO 17. toW~ CHULITNA 18., CACHE 19. GREENSTONE 2.0. TAl.KmNA 2 2 I • GRANITE' GORGE 22.. JCEETNA 2.3 • $f;t!EP CREEK 24. SKWENtNA 25. TALACHUUTHA SCALE· MILES I IN"'..H EQUALS APPROXIMATELY 40 ~ILS:S 26. SNOW 27 , KENAI lOW~ 28.. GERSit.E 29. TANANA R. 30. aRIJSKASNA 3 r • KANTISHNA R. 32.. UPPER BEt:UGA 33.. COFFEF. 34.. GtJLI<ANA R. 3S. KLUTINA 3€..; BRAot.EY LAKE 31.-HICktS :SITE 38.. LOwE 0 > 100 Mil 39. LANE ~. TOI<ICHITNA 41, .'fENTNA 42 • CATHEDRAl. l!l.UFFS 43. .JOHNSON 44• BROWNE 45 • JUNCTION lS. 46. VACHON IS. 47 ~ TAZILNA 48. I<ENAI I.AI<E 49 , CHAAACHAMf'!-t SELECTED ALTERNAtiVE HYDROELECTRIC SiTES I I I I I I I I f I I I I I I I t I I I 3= :e 2 0 0 0 10 8 :c ~6 0 0 0 >- <.!) 0::4 w :z llJ 2 715 J954 1~80 1990 2000 2010 LEGEND DISPATCHED KEETNA J ·CHAKACHAMNA EXISTING AND COMMITTED 0----~--------------------------~--------~----------------~ 1980 i990 2000 2010 TIME GENERATION SCENARIO INCORPORATING THERMAL AND ALTERNATIVE HYDROPOWER DEVELOPMENTS ... MEDIUM LOAD FORECAST-·FiGURE 6.4 -----------------~- PREVIOUS STUDIES UNIT TYPE SELECTION COAL= 100 MW 250 MW 500 MW COMBINED CYCLE i 250 MW GAS TURBINE : 75 MW DIESEL :. 10 MW PLAN FORMULATiON OBJECTIVE ECONOMIC COMPUTER MODELS TO EVALUATE SYSTEM WIDE ECONOMICS EVALUATION OBJECTIVE GAS RENEWALS NO GAS RENEWALS ECONOMIC NO GAS RENEWALS -LEGEND FORMULATION OF PLANS INCORPORATING ALL-THERMAL GENERATION STEP NUMBER lN · STANDARD PROCESS ( t-.PPENO'X A} fiGURE 6 •. 5llllm l I I I I I I I I I I I I I I I I I I I 7 -SUSITNA BASIN The purpose of this section is to describe briefly the physical and biological environment of the Susitna River Basin, particularly in the area of the proposed development. This section was prepared utilizing existing literature, previous studies, and field studies conducted in 1980 and 1981, specifically for the Susitna Hydroelectric Pro'Ject. 7.1 -Climatology The climate of the Susitna Basin is generally characterized by cold, dry winters and warm, moderately moist summers. The upper basin above Talkeetna is domin- ated by continental climatic conditions, while the lower basin falls within a zone of transition between maritime and continental climatic influences. This sec cion summarizes avail able historical climatic data for the basin and programs of field data collection and analysis undertaken during the study period. (a} Climatic Data Records Climatic data, including temperature, precipitation, wind~ cloud cover, humdity, etc., have been collected by the National Oceanic and Atmospheric .l\dministration (NOAA) at a number of stations in the southcentral region of Alaska since 1941. Prior to the current studies, there were no stations locate~ within the Upper Susitna Basin above Talkeetna. The closest sta- tions fot"' which long-term climatic data are available are located, in rela- tion to the upper basin, at Talkeetna to the south and Summit to the north. Typically, NOAA records are presented as annual summaries with comparative data for each station (see Table 7 .1). Monthly summaries are avail ab1e for most of the parameters presented on a daily basis, with se 1 ected parameters at three hour or one hour intervals. Six climatic stations were established in the upper basin during 1980 to facilitate better definition and interpretation of the available historical data. The locations of the stations were finalized after careful evalua- tion of the basin characteristics and a reconnaissance field survey to en- sure a good representation of basin climate and hydrologic characteristics, and to accommodate the climate data requirements of the Alaska Depar·tment of Fish and Game (ADF&G). The stations are located near the Watana camp, Devil Canyon damsite, Kosina Creek (ADF&G), Tyone River near the marsh- 1 ands, at Den a 1 i, and adjacent to the Sus i tn a Glacier, and are shown in Figure 7 .1. Each station equipment comprises a mi.croprocessor-based con- tinuous weather monitoring system -Weather Wizard Model 5100; manufactured by Meteorology Research Inc. of California. The automatic recording system was selected in preference to conventional mechanical recording instruments due to considerable ease of operation and savings in data processing costs. The data collected at these stations ·include air temperature, wind speed and direction, peak wind gust, relative humidity, precipitation, and solar radiation .. Snowfall amounts are measured in a heated precipitation bucket at the Watana Station. Data are recorded at 30 minute intervals at 7-1 the Susitna Glacier station and at 15 minute intervals at all the others. A typical monthly summary of the data for the Watana Station is presented ·in Table 7.2. Detailed summaries of data collected at the six stations are presented in Appendix Bl. (b) Prec\pitation Precipitation in the basin varies from low to moderate amounts in the lower elevations to heavy in the mountains. Mean annual precipitation of over 80 inches is estimated to occur at elevations about 3,000 feet in the Talkeetna Mountains and the Alaskan Range, whereas at Talkeetna station, at Elevation 345, the average annual precipitation recorded is about 28 inches. The average precipitation lessens in a northerly direction as the continental climate starts to predominate. At Summit station (Elevat"ion 2397), the average annual precipitation is only 18 inches. The seasonal distribution of precipitation is similar for all the stations in and surrounding the basin. At Talkeetna, records show that 68 percent of the total precipitation occurs during the warmer months (May through October), while only 32 percent is recorded in the winter months. Average recorded snowfall at Talkeetna is about 106 inches. Generally, snowfall is restricted to the months of October through April, with some 82 percent snowfall recorded in the period November to March. Typical precipitation recorded at various NOAA stations is presented in Table 7.3. The U.S. So i 1 Conservation Service ( SCS) operates a network of snow course stations 1 n the basin, and records of snow depths and water content al~e available as far back as 1964. The stati·ons within the Upper Susitna Basin are generally located ·at elevations below 3,000 feet; they indicate that annual snow accumulations are around 20 to 40 inches and that peak depths occur in late March. There are no historical data for the higher eleva- tions. The basic network was expanded during 1"980 with the addition of three new snow. courses on the Susitna Glacier (see Figure 7.1). A program of data collection started in the winter of 1980 and will continue through the winter of 1981-82. Results of the snow· surveys are being published by SCS in their monthly bulletins. Selected information was used in there- evaluation of the probable maximum flood studies (see Appendix BS). (c) Temperature Typical temperatures observed from historical records at the Talkeetna and Summit stations are presented in Table 7.4. It is expected that the t~m~ peratures at the damsites will be somewhere between the values observed at these stations. Typical values observed at Watana in 1981 are shown in Table 7.2. Three hourly and monthly summaries of data recorded at the s1x climatic stations are presented in Appendix B1. (d) Evaporation The closest stations to the Upper Susi tna Basin where pan-evapor at 1 on data are collected are at the Matanushka Valley Agricultural Experiment Station near Palmer and the University Experiment Station in Fairbanks. The period of record for each station dates from 1944 to the present, with numerous 7-2 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I (e) gaps. Evaporation measurements are restricted to the summer months. A standard Weather Bureau Class A plan was installed near the \tlatana Camp, and daily observations were made during the summer of 1981. An estimate of potential monthly evaporation from the proposed reservoir surfaces was made from analysis of the historical data and measurements at ~Jatana. Table 7.5 presents a comparative picture. Details of this analysis are presented in Appendix 82. Field Data Index A Field Data Index'of all available climatic and hydrologic data for the Susitna Basin was compiled in June, 1980. Updates were made every six months to inc 1 ude data co 11 ected d. uri ng the period of study. The 1 a test · update (January, 1982) may be consulted for a more detailed outline of available data. The Index served the purpose of a formal transmittal of information on data availability to study partj.~ipants and agencies. 7.2 -Hydrology Historical streamflow data are available for several gaging stations on the Susitna River and its main tributaries. Continuous gaging records were avai 1- able for the following eight stations on the river and its tributaries: Mac- laren River near Paxson, Denali, Cantwell, Gold Creek and Susitna stations on the Susitna River, Chulitna Station on the Chulitna River, Talkeet~a on the Talkeetna River·, and Skwentna on the Skwentna. River. The longest period of re- cord is available for the station at Gold Creek (30 years from 1949 to 1970). At other stations, record length varies from 6 to 23 years. Gaging was continued at a 11 these stations as part of the current program, and continuous streamflow data are available for an additional two years (1980 and 1981). A gaging station was established at the vJatana damsite in 1980, and streamflow records are available for the study period. No historical streamflow data al"'e available for the proposed dams·ites at Watana and Devil Canyon. Partial streamflow records are available at several other stations on the river for var;)'ing periods; the stations are shown in Figure 7.1. For details of available records at each station, see Field Data Index (Reference 1). (a) Water Resources Above its confluence with the Chulitna River, the Susitna contributes approximately 20 percent of the mean annual flow measured at Susitna Sta- tion near Cook Inlet. Figure 7.2 shows how the mean annual flow of the Susitna increases towards the mouth of the river at Cook Inlet. Seasonal variation of flow in the river is extreme and ranges from very low values in winter (October to April) to high summer values (May to Septem- ber). For the Susitna River at Gold Creek," the average winter and summer flows are 2,100 and 20,250 cfs respectively, i.e., a 1 to 10 ratio. The monthly average flows in the Susitna River at Gold Creek are given in figure 7 .3. On the average, approximately 88 percent of the streamflow re- corded at Gold Creek stat ion occurs during the summer months. At hi ghel". elevations in the basin, the distribut.ion of flows is concentrated even 7-3 I more in the summer months. For the Maclaren River near Paxson (Elevation I 4520)," the average winter and summer flows are 144 and 2,100 cfs respec- tively~ i~e~ a 1 to 15 ratio. The monthly percent of annual discharge and mean monthly discharges for the Susitna River and tributaries at the gaging I stations above the Chulitna confluence are given in Table 7~6. (b) Streamflow Extension Acres' inhouse FILLIN computer program was used to fill in gaps in histori- cal streamflow records at the eight continuous gaging stations. The 30- year record (up to 1979) at Go 1 d Creek was used as the base record. The procedure adopted for the filling-in of data gaps uses a multi-site regres- sion technique which analyzes monthly time-series data. Flow sequences for the 30-year period were generated at the remaining seven stations. Using these flows at Cantwell station and observed Gold Creek flows, 30-year monthly flow sequences at the Watana and Devi 1 Canyon damsites were gener- ated on the basis of prorated drainage areas. Table 7.7 shows recorded monthly flows at Gold Creek for the entire period of 32 years. Synthesized flows at the Watana and Devi 1 Canyon damsites are presented in Tables 7.8 and 7 .9. Flow duration curves based on these monthly estimates are pre- sented for Watana and Devil Canyon damsites in Figures 7.4 and 7.5. De- tails of the regression analysis are presented in Appendix 82. (c) Low Flow Frequency Duration Analysis A frequency analysis of run-off volumes at low flow periods of durations ranging from 1 to 10 years was carried out for recorded annual streamflows at Gold Creek. The lowest annual flow was observed in the Water Year 1969 with an average flow of 5,560 cfs. The return period of such an event is estimated at about 1 in 10,000 years (see Figure 7.4). A monthly simulation of the proposed reservoirs and power development has been carried out to estimate energy potential of the proposed reservoirs. The critical low flow sequence for energy generation was observed to be the 32-month period between October, 1967 and May, 1'970. The sequence com- prises the lowest annua 1 flow year described above and has a frequency of recurrence of 1 in 300 years (see Figure 7.6). The results of the analysis have been used to determine dependable energy potential of the proposed reservoirs (see Section 15.6). (d) Floods The most common causes of flood peaks in the Susitna River Basin are snow- melt or a combination of snowmelt and rainfall over a large area. Annual maximum peak discharges generally occur between May and October with the major 1 ty, approximate 1 y 60 percent, occurring in June. Some of the annua 1 maximum flood peaks have also occurred in August or later and are there- sult of heavy rains over large areas augmented by significant snownelt from higher elevations and glacial runoff. Table 7.10 presents selected flood peaks recorded ·at different gaging stations. 7-4 I I I I I I I ·I I I I "I I I I A regional flood peak and volume frequency analysis was carried out using the recorded floods in the Susitna River and its principal tributaries, as well as the Copper, Matanuska; and Tosina rivers. These analyses were con- ducted for two different time periods: the first period, after the ice breakup and before freezeup (May through October), contains the largest floods which must be accommodated by the project. The second period represents that portion of time during which ice conditions occur in the river (October through May). These floods, although smaller, can be accompanied by ice jamming and must be considered during the construction phase of the project in planning the design of cofferdams for river diversion. · A set of multiple linear regression equations were developed using physio- graphic basin parameters such as catchment area, stream length, precipita- tion, snowfall amounts, etc., to estimate flood peaks at ungaged sites in the basin. In conjunction with the analysis of shapes and volumes of re- corded large floods at Gold Creek, a set of project design flood hydro- graphs of different recurrence intervals were developed (see Figures 7.7 and 7.8). - The results of the above analysis were used· for estimating flood hydro-- graphs at the damsites and ungaged streams and rivers along the access road alignments for design of spillways, culverts, etc. Table 7.11 lists mean annual, 50-, 100-, and 10,000-year floods at the Watana and Devil Canyon damsites and at the Gold Creek gage. Details of the regional flood fre- quency analysis are presented in Appendix 84. The proposed reservoirs at Watana and Devil Canyon would be classified as 11 large 11 and with uhigh hazard potential" according to the guidelines for safety inspection of dams laid out by the Corps of Engineers. This \~ould indicate the need for the probable maximum flood (PMF) to be considered in the evaluation of the proposed projects. Estimates of the PMF in the Susitna River at several locations, including the proposed damsites, were carried out by the Corps_of Engineers (COE), Alaska District, in their 1975 study of the Susitna Basin Hydroelectric Developments. A detailed review of their work by Acres suggested that the PMF estimate made by the COE was extremely sensitive to the three major parameters-probable maximum pre- cipitation, available snm>~ pack for melting, and the temperature sequence during the PMF event. A reev a 1 uati on·· of the PMF in the basin was, there- fore, undertaken based on a more comprehensive climatological data base and refined basin modeling parameters using the basin simulation program ustreamflow Synthesis· and Reservoir Regulation 11 (SSARR) used by the COE in their study. The details of this study, including a review of the work undertaken by the COE, are presented in Appendix 85. Estimated peak dis- charges during the PMF at selected locations are included in Table 7.11, and the PMF hydrograph is presented in Figure 7.9. (e) River Ice The Susi tna River usua 11 y starts to freeze by 1 ate October. River ice ~on ditions such as thickness and strength vary according to the river. channel shape and slope and, more importantly, with river discharge. Periodic measurements of ice thickness at sever a 1 1 oc at ions in the river have been 7-5 carried out during the winters of 1961 through 1972. The maximum thick- nesses observed at sele-cted locations on the river are given in Table 7 .12. Ice breakup in the river commences by late April or early May; ice jams occasionally occur at river constrictions, resulting in rises in the water level of up to 20 feet. Detailed field data collection programs and studies were undertaken to identify potential problem areas and to develop appropriate mitigation measures should the Susitna project be undertaken. ·The program included comprehensive aerial and ground reconnaissance and documentation of freeze-. up and break-up processes during the 1980-81 season. These data were used to calibrate computer models 1n order to predict the ice regime under post- project conditions in the proposed reservoirs and in the downstream river. Evaluations of the impacts of anticipated changes in ice conditions caused by the proj.ect have been made and mitigation measures proposed. For de- tails of field investigation programs and the analysis, see Appendices Bl and B7. (f) Ri-ver-Morphology and Sediment Yield ( i) Av ai 1 ab 1 e Oat a Suspended sediment data have been collected by the USGS at 13 sta- tions on the Susitna and its tributaries for periods ranging from one season at sma 11 tributaries is up to 22 years at Go 1 d Creek St a- t ion. Figure 7.1 shows location of the stations. Generally, sus- pended sediment concentration, volume of transport and particle size data is co 11 ected by the USGS. Most of the suspended sediment is transported during the spring/summer months June through September. Except for a few samples collected by USGS at Denali in 1958, bed load data for the river and its tributaries are non-existent. Data coverage during high flow-high sediment discharge events was poor and consequently any estimate of total annual sediment yield has a high degree of uncertainty. (ii) Field Investigations During the study p~ri od, several of the USGS sediment stations \'lere revitalized and suspended sediment data collected. In addition~ data was collected at Cantwell and Gold Creek Stations during specific events such as rising and falling limbs of flood hydrographs to fill gaps in historical information. During 1981, three bedload samples were collected at four stations -Susitna River at Gold Creek and Sunshine, Chulitna River near Talkeetna and Talkeetna River near Talkeetna to enable better understanding of river morphology below damsites. (iii) Estimate of Sediment Yield Historical data and those collected during the study period were analysed to estimate sediment yield in the river at various loca- tions and potential reservoirs sedimentation. Suspended sediment rating curves have been developed for stations on the Susi tna at Gold Creek, Cantwell, Denali and at Paxson on Maclaren River (see 7-6 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I River (see Figure 7 .10) . Esti m·ated annual transport of suspended materials at selected gaging stations is presented in Table 7.13 .. Without adequate bedload measurement.s above the damsites, estimates had to be made based on earlier studies (1975) by the Corps of Engineers and data collected at Gold Creek for potential bedload movement into the reservoirs. · Trap'· effi ci enci es for the proposed reservoirs at Watana and Devil Canyon were made based on literature surveys of worldwide experience under similar glacial river bdsins .. Table 7.14 presents estimated sediment deposition in the reservoirs. Details of reservoirs sedimentation analysis may be found in Appendix·sa. (iv) Morphology of River Below Dams Preliminary studies of the morphology of the river below the pro- posed dams have been made to evaluate potential changes caused by post-project flow regime. A detailed report has been prepared on the subject and is presented as Appendix 89. The study indicates that s'ignificant changes in the lower river morphology are unlikely to be caused by the projects proposed. 7.3-Regional Geology The regional geology of the Susitna Basin area has been extensively studied and is documented {1!12,3). The Upper Susitna Basin lies within what is geologically called the Talkeetna Mountains area. This area is geologically complex and has a history of at least three periods of major tectonic deformation. The oldest rocks exposed in the region are volcanic flows and limestones which were formed 250 to 300 million years before present (m.y.b. p) \vhi ch are overlain by sandstones and shales dated approximately 150 to 200 m.y.b.p. A tectonic event approximately 135 to 180 m.y.b.p. resulted in the intrusion of large diorite and granite plutons, which cau.sed intense thermal metamorphism. This \vas follQwed by marine deposition of silts and clays. The argillites and phyllites which predominate at Devil Canyon were formed from the silts and clays during fau1ting and folding of the Talkeetna Mountains area. in the Late Cretaceous period {65 to 100 m.y.b.p.). As a result of this fawlting and uplift, the eastern portion of the area was elevated~ and the oldest. volcanics and sediments \>/ere thrust over the younger metamorphics and sediments. The major area of deformation during this period of activity was southeast of De vi 1 Canyon and inc 1 uded the. Wataa1a area. The Talkeetna Thrust Fault, a well-known tectonic feature which has been identified in the literature, trends northwest through this region~ This fault was one of the major mechanisms of this overthrusting from southeast to northwest. The Devi 1 Canyon area was probably deformed and subjected to tectonic stress during the same period~ but no major deformat 1 ons are evident at the site (Figure 7.11). The diorite pluton that forms the bedrock of the Watana site was intruded into sediments and volcanics about 65 m.y.b.p. The andesite and basalt flows near the ~ite may hcve been formed immediately after this plutonic intrusion, or afte'r a period of erosion and minor deposition. 7-7 ---,--,.---~-~~~~-~~-~-----::---;----~-~---~ --~ ------_-,------o-;-----:-; --~ -~ ~-~--. - ------.-.,...---~~------,----------c--------~--;::"~-~----.-.-~~.....,-----~--. '·~ During the Tertiary period (20 to 40 m.y.b.p.) the area surround1ng the sites was again uplifted by as much as 3,000 feet. Since then, widespread erosion has removed much of the older sedimentary and volcanic rocks. During the last sev- eral million years, at least two alpine glaciations have carved the Talkeetna Mountains into the ridges, peaks, and broad glacial plateaus seen today. Post- glacial uplift has induced downcutting of streams and rivers, resulting in the 500-to-700 foot deep V-shaped canyons ·that are evident today, particularly at the Vee and Devil Canyon damsites. This erosion is believed to still be occur- ring and virtually all streams and rivers ·;n the region are considered to be actively downcutting. ~his continuing erosion has removed much of the glacial debri-s at higher elevations but very little alluvial deposition has occurred. The resulting landscape consists of barren bedrock mountains, glacial till- covered plains, and exposed bedrock cliffs in canyons and along streams. The arctic climate has retarded development of topsoi 1. 7.4 -Seismicity ---~-=- (a) General The Talkeetna Mountains region of south-central Alaska is considered to be highly seismic with numerous reported earthquakes of moderate-to-large magnitude. Therefore, in order to assess the risk of seismic exposure of the Susitna Basin development and to define the earthquake design parameters for the critical project structures, a comprehensive study was undertaken as a part of the feasi bi 1 ity study. A brief summary of this study is presented in this section. Details of the study are contained in References 1 and 2. The scope of the study was developed to identify and evaluate all potential sources of earthquakes with magnitudes larger than 5 on the Richter scale, to determine the maximum credible earthquake (MCE) for each source and the ground motions associated with the MCE at the project site, and to assess the potential of ground surface rupture near the project structures that could affect the safety and/or integrity of the structures. In addition-:: suffic1ent geologic and seismologic studies were performed to evaluate the probability of Reservoir-Induced Seismicity (RIS) and its impact on the project design. A seismic monitoring network plan was also developed to monitor both micro-earthquake and strong earthquake activities within the Susitna Basin prior to and during the construction of the project and for a period of approximately 15 years after the project is completed and the reservoirs are flooded. · (b) Regional Seismicity and Tectonics . Recent concepts of plate tectonics have been a major influence in the in- terpretation of the current tectonics of Alaska. The earthquake activity- in central and southern Alaska is caused by the subduction of the Pacific Plate under the North American Plate at the Aleutian Trench (Figure 7.12). The Pacific Plate spreads northward at a rafe of approximately 2.4 inches/ year relative to the North American Plate. This movement in the Gulf of Alaska is expressed as three styles of deformations: right lateral slip along the Queen Charlotte and Fairweather Faults, underthrusting of the 7-8 I I I I I I I I I I I I I I I I I I ~I, :~ : . I I I I I 'I 'I I I I I I I I I I I I I oceanic Pacific Plate beneath the continental block of Alaska, and the complex transition zone of oblique thrust faulting near the eastern end of the Aleutian Trench. This subducting plate dips gently under the Upper _susitna River region. Historically, major earthquakes in Alaska have occurred primarily along the interplate boundary between the Pacific and the North American Plate. For ex amp 1 e, three great earthquakes of September, 1899 (estimated magnitudes 8.5, 8.4 and 8.1) were felt near Yakulat Bay. Similarly, an earthquake of magnitude 7.7 in Lituya Bay in 1958, one of magnitude 7.6 in 1972 near Sitka, and the devastating 1964 Alaskan earthquake occurred along the plate contact. Nevertheless, the overlying North American Plate is also disrupt- ed by the compression a 1 and tension a 1 forces caused by the i nterp 1 ate move- ments (approximately 2.4 inches/year). The strain buildup and release \ caused by this movement within the crust takes place along a series of faults and also generates earthquakes of small-to-moderately large magni- tude within the crust with no surface expressions. Avai lab 1 e information suggests that the sum of ·the rates of disp 1 acement along faults in southern Alaska is less than the rate of convergence of the Pacific Plate relative to the North American p 1 ate and that a si gni fi cant portion of that ·unaccounted-for convergence is transmitted northward. This has resulted in broad folds and reverse faults, northward thrusting of the Alaska Range northern front, and the overall uplift of the Alaska Range. The site region of interest for the Susitna Basin development lies bet\'Jeen the Aleutian Trench and the Alaska Range and has been termed the Talkeetna Terrain. (c) Tectonic Model of Talkeetna Terrain The Talkeetna Terrain is a subunit of the larger tectonic unit, the Wrangell Block (Figure 7 .13). The terrain is defined by the McKi n 1 ey strand of the Denali Fault on the north, the Denali-Totschunda Fault system on the east, the Castle Mountain Fault on the south, and a zone of deforma-. tion on the west extending from the Aleutian volcanic chain to Mt. Denali (formerly Mt. McKinley-Figure 7.13). The north, south, and east boundary faults are faults with recent displacements, and the western boundary is primarily a zone of uplift marked by Cenozoic volcanos. The subducting Pacific Plate, called the Benioff Zone~ bounds the base of the Talkeetna Terrain. At the southern boundary of the Talkeetna Terrain, the Benioff Zone is decoupled from the North American Plate. Most of the deformation in the Talkeetna Terrain caused by the converging plates appears along the boundaries; the inte·rior region is relatively stable .. A schematic section showing th~se boundaries is presented in Figure 7.1~. Much of the interplate convergence, in the form of strike-slip faults, is believed to lie within a broad area of deformation extending from Montague Island east to Pamploma Ridge in the Gulf of Alaska. A small amount of movement occurs within the castle Mountai"n Fault, which is decoupled from the Benioff Zone in the site region. This fault is a right-lateral, strike-slip fault with a significant component of the northside up reverse component. The Denali and the Totschunda faults are right-lateral, strike- 7-9 ' slip faults ·that exhibit progressively lower slip rates northward and westward. Within the Talkeetna Terrain, two major geologic structures, the Broxson .... Gulch Fault and the Talkeetna Thrust Fault, are present. The Talkeetna Thrust Fault is an old geologic feature ~ith no signs of recent movements. The Broxson-Gulch Fault, although considered to be active in accommodating some of the movement along the Denali-Totschunda Fault, is outside the area of study and is not considered signifitant for the project studies. Most of the moderate-ta-l arge earthquakes and a 11 the 1 arge earthquakes within the Talkeetna Terrain are associated with either the Benioff Zone or the boundary faults. The terrain itself is relatively stable with no brittle deformation related to the current stress conditions. (d) Historical S~ismicity Within 200 miles of the project site, the earth~uakes generally originate from three sources: the shallow Benioff Zone, the deep Benioff Zone, and the crustal seismic zone within the North American Plate. The shallow Benioff Zone is a major source of earthquake ac~i viti es. The major 1964 earthquake of magnitude 8.5 occurred on this source. Several additional large eart~quakes have been reported in the same vicinity during the twentieth century. The focal depth of these earthquakes is generally 15 to 28 miles. The deeper Benioff Zone dips gently under the North American plate and reaches a depth of approximately 31 miles beneath the Watana site and 37 miles beneath the Devil Canyon site. -t~derate-to-large size earthquakes have been reported on this source within-the site region. The largest re- ported event within the 60-mile radius has been magnitude 6.L. The crustal seismicity is related to the Talkeetna Terrain boundary faults; namely~ the Denali and the Castle Mountain Faults and the strain release within the crust with no sur-face faults. Moderate-ta-l arge earthquakes have been reported along the two faults. Within the terrain, numerous moderate-size eartthquakes with a 1 argest reported magnitude of 5.6 have been reported. (e) Identification and Screening of Faults The project site ·is remotely located and the area had not been studied in detail for hydroelectric devel'opmen prior to this study program. There- fore, a systematic and comprehensive study was undertaken to identify faults in the area. A fault-screening methodology was developed to di~ect efforts in studying si gni fi cant features (Figure 7 .15). All lineaments within 62 miles of either site were reviewed using this methodo 1 ogy. A 11 av ai 1 ab 1 e 1 iter ature and remote 1 y sensed data was r e- searched and reviewed. More than 400 features were identified from this r~view and were further screened using a length-distance criteria. All features within 6 miles of either project site were identified for their potentia 1 for surface rupture and during an earthquake. This first step resulted in a list of 216 features that required further study. Throughout this screening process, the following criteria were used in identifying and studying the faults with recent disp.lacement: 7-10 I I I 1: I I I I I I I" I I I I I I I I I I I I I I I I I I I I I I I I I I I -All features identified as faults that have experienced movement in the last 100,000 years were considered to have had recent displacement. All faults with recent displacement were considered as potential sources fo~ ground motion and surface displacement. -All lineaments or faults that have been defined by the geology and seis- mology community as having experienced recent displacement were included for further study in assessing the seismic design criteria for the pro- ject. -If a lineament existed within 6 miles of the damsite, or if a branch of more distant lineamn!'lt was suspected of passing through a damsite, then a more detailed investigation was made to establish whether the feature was a fault~ whether or not it was recently displaced, and whether the poten- tial for displacement in the dam foundation existed. -Lineaments farther than 6 mi 1 es from the damsi tes for which determi ni sti c estimates of ground nH1tion at the site may control the design of a dam were investigated to determine if the lineament was a fault and if it had recently undergone displacement. -Therefore, at a distance of less than 6 miles from the damsite, all _ faults or lineaments with a length of 3 miles or more were selected for field study. A fault of this length has a potential for an earthquake with a magnitude of 5 or greater. All faults or lineaments 6 miles or longer at a distance of 6 to 31 miles, and 31 miles or longer at a' distance of 31 to 93 miles, were also selected for field study. This process resulted in a list of 216 features that were identified for field study on a reconnaissance level. (f) Field Reconnaissance Studies The 216 features were further studied in the field during the summer of 1980. Aerial and ground reconnaissance work was conducted for a 11 these features by experienced teams of geologists. Flights were made along these lineaments in both directions looking fqr morphologic features. The features were photographed at key locations for later studies and documentation. For some long faults or lineaments, the feature was ex ami ned in det ai 1 on the ground. A systematic method was again used to identify significant features. Line- aments that could be related to glacial or fluvial processes were elimin- ated from further considerations. This resulted in a group of 106 features for further screening (see Ta.ble 7 .15) using the following criteria: -Any feature less than 3 miles in length (potential a magnitude for 5-or- 1 ess earthquake) was not studied any further un 1 ess that features wa.,s within 6 miles of the project site. -Features that would generate a peak acceleration of 0.15g or less if they were faults were eliminated. This acceleration is less-than the accelerjtion caused by a Denali Fault earthquake of magnitude B.S at 40 miles from either damsite. The Denali Fault was recognized as an active fault and therefore a source of earthquake concern. 7-11 (g) ~----::----~-----:;--- -Two features, KC 4-27 at the Watana site and KC 5-43 at the De vi 1 Canyon site, were less than 3 miles long; however, they were retained for further stud 1 es because of their proximity to the dams 'ites and associ a ted potential ground rupture. With this process, 58 features were eliminated, leaving 48 features for further consideration. These 48 features were evaluated in greater detai 1 on the basis of their potential impact on the design of the project and the likelihood of a feature being a fault on the basis of field reconnaissance. This evaluation resulted in identification of 13 significant features that could potentially impact the design of the project. These features and the boundary faults are listed in Table 7.16 and were studied in detail during the 1981 summer season. TI1e four features located near the Watana site are shown in Figures 7.16 and 7.17. The remaining nine features were near the Oevi 1 Canyon site and are shown in· Figures 7.18 and 7.19. Detailed Field Studies • The significant features identified during 1980 were studied in much more d-etail during 1981. The approach used to guide the field studies was to: -Study the bedrock a long each feature to assess whether or not the feature was a fault; and -Examine the surficial units along the features to avaluate ~~heH the displacement occurred. The detectability of faults with recent displacement is dependent on the age of sediments overlyi;Jg the fault, the amount of displacement at the surfac1.: during an earthquake, how often the earthquakes and the displace- ments occur, the type of displacement, the length of fault that experienced displacement, and the time that the displaced features are preserved. On the basis of the site fault morphology, review of a select group of world-· wide data and a review of moderate-ta-l arge hi stori ca 1 earthquakes in Figure 7.16 shows the boundary faults, Talkeetna Thrust Fault and· the Susitna feature. In Ca 1 iforni a (where the studies are much more complete), it was judged that any fault which has experie11ced displacement for a length of 9 miles or longer and a scarp height of 2 to 3 feet would be recognized during the field studies. It was recognized that recent displacement along a fault could go cnrecognized if the length of ·displacement was less than 9 miles and the scarp height was less than 2 to 3 feet or both; however, such a displacement would be associated with a magnitude of 6 or less earthquake. The first step in this investigatior consisted of quaternary g~ology map- ping in the site region to determinl or estimate the age of surficial sedi- ments and geomorphic surfaces neC:i"' the 13 features. The ·extent, magnitude, and chronology of the repeated glacial events affecting the Talkeetna Terrain was reconstructed using stratigraphic and morphologic relationships and relative and radiometric age dating techniques. The results of ai·r photo interpretation of stereographir. aer13.l photographs, published works by other investigators, and field mappin~ were used· supplemented by age determinatior of soil samples from selected locations. · 7-12 I I I I I I I I I I I I I I I I I •• I I: I • I I I I I I I 'I I I I I I I I I ., . '. --.---:-~-... -, The geologic setting of the Talkeetna Terrain is largely one of crystalline bedrock and bedrock overlain by thin glacial cover. No deep Neogene subbasins exist that could conceal faults and the effects of recent displacements. Thus the incidence o·f recognizing faults is rather high. The Quaternary geology and bedrock geology studies were performed along these 13 features using 1 ow 1 eve 1 aeri a 1 reconna.i ssance and ground "tech- niques. The data were integrated with the results of historical seismicity and microseismic network data and ground mapping was conducted at 300 locations. Two trenches were excavated across the inferred location of the Talkeetna Thrust Fault and one trench across the inferred location of the Susitna feature (see Figure 7.13). In addition, magnetic surveys were performed at locations across the Talkeetna·Thrust Fault, locations across the Susitna features, and locations on other features. During the ground examination;') 28 samples were collected from 15 different locations for age dating, and five test pits were dug with a backhoe for relative age dating. In addition, low sun angle photographs were taken of selected features to improve the level of resolution. A ten seismograph station microseismic network \'las operated dur'i ng the period from June 25, 1980 to September 28, 1980 around the Watana and Devil Canyon sites. The location of the network stations is shown in Figures 7.20 and 7~21. The objective of this network was to co 11 ect a 1 arge quantity of mi croearthquake data within a re 1 ati ve ly short period of time. A total of 268 earthquakes were recorded during ~he periods, 98 of which uccurred below a depth of 19 miles (in the Benioff Zone); the remaining 170 occurred within the crust. The largest magnitude recorded was 3.6& for the deep earthquakes and 2.8 for the sh~llow earth- quakes. The locations of the shallow earthquakes are shown in Figure 1.20~ and the deep earthquakes in Figure 7.21. The results of this microseismic network were used in conjunction with geologic and seismologic studies to determine current activity along known/inferred faults, to determine the Benioff Zone depth in the site region, and to deve 1 op frequency -magnitude relationships for the study area. A cross-section through the site, show- ing the shallow and deep earthquakes recorded during this period, is pre- sented in Figure 7. 22. .The resu 1 ts of these studies were w·ed to assess the recency of displacement along faults 1}r features, with the following results: ... From the 13 features selected for the study, only four features wet"e determined to be faults: the Talkeetna Thrust Fault and the Fins at the Watana site, and KC5-5 and KD5-2 at the Devi 1 Canyon site. The J"'emaining nine features were determined not to be faults. The features that are not faults were not considered to be significant in the design of the project under earthquake conditions. -The four features that were determined to be faults did not meet the guidelines for a fault with recent displacement. Therefore, these are not considered to be possible sources of earthquake activity for the project. -The only known sources of earthquake activity are the Denali Fault, the Castle Mountain Fault, the Benioff Zone, and a fault within the crust with no detectable surface trace. 7-13 {,.,_.....-... ,:>..,...,' ; (h) -The Benioff Zone under the site is decoupled from the crust. The approx1mate depth to the upper boundary of this zone is estimated to be miles under the Watana site and miles under the Devil Canyon 'site. -There i~ a seismic belt of low seismic activity between the crust in the site region and the shallow Benioff Zone. ~ No microearthquake activity was found to be related to the Talkeetna Fault or any other feature. Sources of Earthquakes in Susitna Basin Based on the studies conducted to date, four sources of earthquakes have been identified for the design of the project. These sources and the asso- ciated maximum credible earthquakes are summarized in Table 7.17 and brief- ly discussed in Sections 9 and 10. (i) Denali Fault System { .. ·;) 1 I 1 This strike-slip fault system lies to the north of the site region and connects with the Totschunda and the Fairweather Fault system to the east and the southeast. One section of this fault could be as long as 670 miles; this fault is considered capable of causing a magnitude 8 earthquake~ Castle Mountain Fault This strike-slip fault lies outside the limits of the area studied and forms the southern boundary of the Talkeetna Terrain. It is ap- proximately 295 miles long and capable of generating a magnitude 7.5 earthquake .. (iii) Benioff Zone This is the most dominant of a 11 sources. The Benioff Zone is divided two discrete segments for earthquake considerations; the Interpl ate Zone and the Intraplate Zone. These zones are separated by a transition zone of relatively low seismic activity. -Interplate Zone: This zone represents the interface between the Pacific Plate and the North American Plate. The depth of this zone is estimated to be less than 35 km. The maximum ~redible earthquake for the source is estimated to be 8.5 magnitude at the c 1 osest distance of 63 km from the ~vat ana site and 90 km from the Devil Canyon site. This magnitude is similar to that of the 1964 J.rt ask a ear·thquake. Intraplate Zone: This port1on of the Benioff Zone is detached from the North American Plate Crust and dips beneath the crust. The earthquakes occur within the subducting plate. The maximum credible earthquake that can be generated by this i ntrap 1 ate zone within the site region is estimated to be magnitude 7.5. The closest this earthquake. can occur to the Hat ana and Devi 1 Canyon sites is 48 km and 58 km~ respective 1 y. 7-14 I I I I I I I I I I I I I I. I I I I •• I I I I I I I -I I I I I I I I I I I I ( i ) {iv) Random Tt:rrain Earthquake As discussed earli..er~ the studies indicate that earthquakes do occur in the crust without; causing recognizab 1 e surface faulting. The magnitude of these earthquakes in-similar seismic environment is moderate and the location is difficult to identify prior to the actual earthquake. For conservative design purposes, it is assumed that these earthquakes can occur very close to the site~ For the Susitna ·Hydroelectric Project, it has been conservatively selected to consider, at the most, a magnitude 6 earthquake to occur within a few kilometers of either project site. Reservoir Induced· Seismicity ( RIS) During the past few decades, it has been accepted that the impoundment of ·1 arge reservoirs affects the sei smi city of the region. This phenomenon was _ first recognized during a study of Hoover Dam in the United States in the early 1940s~ Since then similar relationships have been reported for 63 other reservoirs around the world, of which 55 cases have been accepted as either RIS or questionable cases of RIS (see Figure 7.23). Several RIS events have exceeded magnitude 6~ Recent studies have suggested that RIS is influenc-ed by several considera- tions; the most prominent ones are water depth and reset""voir volume (see Figure 7 ~23), geologic setting and faulting (s~e Figure 7 .24), and the state of tectonic stress (Figure 7.25) in the shall ow crust beneath the reservoir. The study of RIS su~gests that the impoundment of water acts as a trigger~ ing mechanism for the seismic events that would occur at some point 1a time under natural states of stress. Therefore, reservoirs do not reacti vat.e inactive faults or create new faults, but merely accelerate the release of stored tectonic strains. Tni s hypothesis forms the basis of statement that RIS is an important consideration only in those ar.eas where active faults, whether identified or not, exist. It also suggests that the largest event caused by RIS would be less than or equa.l to the maximum credible event on the fault. Further-, it is recognized that RIS events occur mostly within the first ten years of impoundment; after ten years the micro as well as macro seismicity ,return to their natural state after that. Mathemati ca 1 mode 1 s have been developed to assess the probabi 1 i ty of RIS under a given s'et of conditions. For the purpose of this study it has been assumed that both the Watana and Devi 1 Canyon reservoirs act as one hydro- logic regime. Using this assumption and the results of geologic and seis- mologic stuaies, 1t has been estimated that there is a 90 percent probabi 1- i ty of an RIS event of some magnitude occurring. Th-e largest RIS event that cou 1 d occur i"s estimated to be magnitude 6·, which is the same as the maximum credible earthquake with no recognizable trace of faulting at. the surface.. This. estimate is based on the finding that there are no act"i\te faults present within the hydrologic regime of the combined reservoirs~ 7--15 '' D 0 . , . ' ·v. "" .• , ........ .:;_ __ ~~ .. .._ ...... ~·-· -~ ........... "'~·'-"-.: {j) Long-Term Seismic Nonitoring Network A seismic monitoring network will be installed at the Susitna Hydr-oel~ctric project to monitor the seismic activity in the region on a long term basis. This network will be separate from the seismic instrumentation that may be installed in the dam and other structures~ although some components of the network may be 1 ntegrated and may become part of the permanent i nstrumenta- tion. This system will be operated during the design and construction of the project and for a period of 10 to 15 years after the reservoirs are filled. The major objectives of this network will be to monitor the natural seismic activities within the region (both microearthquakes and strong motiori), to monitor the seismic activity after the reservoirs are fi 11 ed (to study and document any change in seismic activity caused by the project), and to calibrate source-distance attenuation curves for this region for a proper ground motion attenuation. The key requi rementsoof this net\~ork wi 11 be to: -Provide reasonably accurate hypocentral locations of 3 earthquakes within 15 to 20 km of the two reservoirs; -Effect good control on the depth and local mechanism of earthquakes; and -Provide a reasonably accurate magnitude of both small and large earth- quakes. For maintenance and operation consideration, a system which provides con- tinuous monitoring, qtiality data, and requires the least possible mainten- ance and repair in this environment will be provided. Such a network, as envisioned at this point, w'ill include 11 vertical com- ponent seismometers ·and two three-component seismometers. Six of the eleven component seismometers will be strong motion instruments. The loca- tions of these siesmometers (conceptual) are shown in FiguY'e 7.16; they were selected to provide the optimum coverage within a region of 15 to 20 km of the reservoir limits. This network will provide good constraint on the. hypocentral locations of all earthquakes that occur· within 20 km of the reservoirs with a foca 1 depth of greater than 5 km. The data from these stations will be collected at a central location at the Watana site and transmitted by VHF radio or hard wire line. A central recording facility will be located at the ~Jatana site. The data will be compiled and pro- cessed by a microcomputer which will continuously scrutinize incoming sig- nals and store them on disc.. Hhen a seismic event is detected, the dlgi ·- tized data wi 11 be copied from disc to tape for permanent storage. Oata from selectP.rt stations will also be recorded asanolog paper recor-ds. These data will be accessible via a telephone telemetry 11nk for rapid transmit., . . tal of data to distant locations. Preliminary data analysis performed by microcomputers will allow quick and timely decision making. 7-16 o·-.;1 I I I I- I I I •• I I I I I I I I I I I I I I I I I I 1: The instrument locations wf11 be selected in the f1eld and proper protective measures will be designed to mitigate the effects of weather and wild habitat .. The number of stations included in the network will provide a sufficient degree of redundency in the network. Although·, the instruments and the system selected will require minimum maintenance and repair, a well-planned regular maintenance and repair program will be. deve 1 oped to assure 1 ong term, uninterrupted data gathering. 7~5 -Water Use and Qualitl (a) Water Use Water rights in Alaska are administered by the Alaska Department of Natural Resources (DNR) 0 The computer fi 1 es of ONR' s water management section were searched to determine the amount and type of water appropriations recorded for the Susitna River and surrounding area. The mainstem Susitna corridor encompasses 30 townships from the proposed impoundment area at Devi 1 Canyon downstream to the estuary. Ex 1 sting sur- face and ground water appropriations are primarily for single-family anct multi-family homes (Table 7.18). A small arnount of water is used year- round for watering livestock. Only 0.153 cfs, or 50 acre feet per year, of surface water has been C\~-·nropriated for all purposes (Table 7 .19).. \slater appropriations in other are\'~ are even less significant. On a seasonal basis, the greatest usage oc~ur·s during summer months for h·rigating lawns, gardens, and crops. The largest single use of surface water is for placer gold operations. There are only five areas where water appropriations are 1 ocated within one mile of the mai nstem Susi tna River (Tab 1 e 7 .20). No surface water d) ver- sions ate recorded that draw water directly from the Susitna River or its adjoining side channels and sloughs. Immediately downstream from the Delta Islands, on the west bank of the Susitna River, a single-family dwelling has a certificat~ for 650 gpd of ground water from a well of unlisted depth. About six miles below Talkeetna and 0.25 miles inland from the west bank of the Susitna River, a single-family dwelling has .a certificate for 500 gpd of ground vJater from a 90-foot deep we 11. In Ta 1 keetna~ ground viater from three sh a 11 ow we 11 s has , been appropriated for a sing l e-fami 1 y dwelling (500 gpd), the grade school (910 gpd}, and the fire station {500 gpd). Near Chase, sever a 1 unnamed· streams·, 1 akes, and creeks have been &ppropriated for single-family dwellings {1,250 gpd), lawn and garden irri- gation (100 gpd), and crops (1 acre foot per year). Near Sherman, an un- named str<:am and Sherman Creek have been appropriated for two single-family dwellings (325 gpd} and lawn and garden irrigation (50 gpd). (b) Water Quality The wide seasonal fluctuations in river discharge and glacial character of the river have a si gni fi cant effect on water qua 1 i ty. Suspended sediment concentrations and turbidity levels are low during late fall and winter, but increase sharply at breakup and remain high throughout summer during the glacial melt period. Dissolved solids concentrations and conductivity values are high during low flm-1 periods and low during the ':1igh summer flows_ 7-17 ,"-,. The Susitna Rivel"· is a fast-flowing"~ cold-water stream of the calcium bi- carbonate type containing soft-to-moderately hard water during breakup and in the summer, and moderately hard water in tJ1e vJi nter. Nutrient concen- trations~ namely, nitrate and ortho-phosphate, exist in low to moderate concentr,ations. Dissolved oxygen concentrations typically remain high, averaging about 12 mg/1 during the summer and 13 mg/1 during winter. Per- centage saturation of di sso 1 ved oxygen always exceeds 80 percent but aver- ages near 100 percent in the summer; in the winter saturation levels de- cline slightly from the summer levels. Typically, pH values range between 7 and 8 and exhibit a wider range in the summer as compared to the winter. During summer, pH occasionally drops below 7, which can be attributed to tundra runoff. True color, also resulting from tundra runoff, displays a wider range dm·ing summer than winter. Color levels in the vicinity of the damsites have been measured as high as 40 color units. The temperature re- mains at or near 32° F during winter, and in summer the maxi mum is 55 oF. Alk~linity concentrations~ with bicarbonate as the dominant anion, are low to moderate during summer~ and moderate to high during winter. The buffer- ing capacity of the river is relatively low on occasion. The concentrations of many trace elements monitored in the river were low or within the range characteristic of natural waters. However, the concen- trations of some trace elements exceeded water quality guidelines for the protection of freshwater aquatic organisms. These concentrations are the result of natural processes, since there are no man-induced sources of these elements in the Susitna River basin. Concentrations of organic pesticides and herbicides, uranium, and gross alpha radioactivity were either less than their respective detecti-Jn limits or were below levels considered to be potentially harmful. 7.6 -Fisheries Resources Both resident and anadromous fish occur in the Susitna River system. Resident fish species present are grayling, burbot, rainbow trout, Dolly Varden, three spined stickleback, lognose sucker, slimy sculpin, whitefish, and lampreys; anadromous fish are sockeye, pink, coho, chinook, chum salmon and eulachon .. Arctic grayling-and rainbow trout, the primar-y resident game species, occur near tributary mouths during the summer months and in the mainstem Susitna during winter. Both species use the mai nstem of the Susitna as a migratory corridor for moving between rivers and streams. Spawning likely occurs i_n the clearer tributaries. Salmon utilize the Susitna River and its tributaries below Devil Canyon as a spawning habitat. Data indicate that physical barriers prevent salmon from mi- grating to the upstre.am part of Devi 1 Canyon. Salmon migration begins in late spring and continues into the fall. Stud'les to date i nd1 cate that· the run of chi nook salmon through the area above the confl u- ence of the Chulitna and Talkeetna Rivers begins around mid-June. Pink salmon arrive in this region during late July and chum salmon migrate here in August and early September. Sockeye sa.lmon appear in July and August . .. · ·'" 'd 7-18 : --· .. ' ,j:.;-.:.__;_.::;;.;;:;.?-::y-.::,;:,~..;::;..~_·,.::-::_;:.:·::.:::::;~...:.~~~.:=.~';_":: :_:;;:::::;· ,'--:~;:~:., I I I. I I I I I I I I I I I I ·I I I :I I I I I I I I I I I I I I· I I I I I I --~ .-, -,-_,~ . -- Following deposition in the fall, the eggs hatch in the spring~ The young salmon, depending on the species and a variety of unknown factors, either migrate to the sea within a few months or remain in the river for one or t\vo years before migrating downstream. 7.7-Wildlife Resources Information presente"'d in the big game sectio·n below was taken from reports prepared for this pr.oject by the Alaska Department of F 1sh and Game. (a) Big Game Species of big game which inhabit the upper Susitna basin are: black bear, brown bear, wolverine, wolf, Dall sheep, caribou, and moose. ( i) Bears Black bear distribution in Alaska coincide with the presence of for- est habitat. Thus, within the Susitna basin most black bear are found in steep terrain along the river and its tributaries. (Infor- mation on habitats, home range, population levels, density to be added) . Studies indicate approximately 55 percent of the population is males. The average spring age is approximately 6-1/2 years for males and 8 years for females. The population appears to be healthy and producing. Dens utilized for overwintering were found primarily at an elevation of 1500 to 2500. Sixteen den sites were found in the vicinity of the proposed Devi1 Canyon impoundment 9only one of which would be flooded) and 13 in the vicinity of the proposed Watana impoundment (9 of which would be flooded). Dens were a.1so found downstream of the Devil·Canyon site. Bears typically entered the dens from mid-September through mid-October and exited from April to mid-May. Black bears are fa.irly abundant in Alaska and not heavily hunted. Within the upper Susitna basin, only an average of eight per year are harvested, primarily between the Talkeetna and Indian Rivers. This number is below the hunter inflicted mortality rate which the population could suffer and maintain its present population level, i.e .. , it is below the maximum sustainable yield for·the population. Brown bear occur primarily in open tundra and grassland areas of · Alaska (Information or habitats, home range, density to be added). Preliminary estimates of brown bear numbers in the study area is 70 animals or one bear per 50 km2 utilizing t~"e same figure would in- dicated 3 to 4 bears in .the area to be flooded. The ~rown be.ar population of the upper Sus itna bas in appears to have a 50:50 sex ratio.. Average spring age is approximately 7-1/2 years for both males and females. The population is young and healthy, with litter sizes equivalent to know productive bear populations in J ... 19 " other areas. Dens were found at elevations ranging from 2330 to 5150:t with an average elevation of 4,181 feet. (Information on numbers of dens in area to be added., if avai 1able). Harvest regulations for brown bears are more stringent than for b 1 ack bears. Only an average of 15 per year are taken by hunters within the project area; this is believed to be below the maximum substainable yield. ( i i) Holveri ne Wolverine are present in the study area, found in all habitat types .. Their distribution appears to be related to prey availability., con- centrating in hilly areas above treeline in the summer and fall and in lower elevations during winter and early spring. Population density is estimated between 1 per 109 km2 (1/42 mi2) and 1 per 144 km2 (1/56 mi2). The entire impoundment area of both Watana and Devil Canyon is approximately 206 km2, indicating an area inhabited by two wolverines. Utilizing the same density figures, the entire upper Susitna basin population is estimated at 150. Harvest· data suggest the wolverine population of the upper Susitna basin may be experiencing heavier trappjng mortality than the population can sustain over a prolortged period. (iii) Wolf (To be written following receipt of report from AOF&G). (iv) Dall Sheep Three populations of Oall Sheep occur in the upper Susitna basin= the Watana hills herd, Watana -Grebe Mountain herd and the Portage -Tsusena Creek herd. Population levels are not known but surveys conducted in 1980-1981 revealed 209 sheep in the Watana hills herd, 30 in the Watana-Orebe Mountain herd and 72 in the Portage -Tsusena Creek herd, for a total of 311. A total of 13 sheep were harvested by sport hunters in 1980 in the Upper Susitna Basin. 7-20 I I I I! 'I I I ··~ I I I I I I I ,. I I I I •• ,• I I I I I I I 'I ··, I I I I I I I I '"~"'----------"'--' A mineral 1 ick in the Jay Creek area appears to be an important area fm' the Watana hills herd. Sheep were frequently observed utilizing the lick, which is located at Elevation 2200 and will be partially inundated qy the Watana reservoir. (v) Caribou The Nelchina caribou ·herd occupies an area of approximately 20,000 square miles in Alaska. This large range can be divided into 16. sub-ranges, including the upper Susitna basin {Figure 7 .28). Por- t ions of the bas in hav1e been consistently .used/) throughout the years by large portions of the herd, with most use taking place in summer, fall, and late winter. During some years, the entire herd, -cur- rently numbering 20,000 anima 1 s, has used this area. A sma 11 sub- herd of approximately 1,000 animals appear to be.residing perman- ently in this portion of the basin. During winter, caribou were found primarily" on the Lake Louise Flat, foothills of the Alphabet hills and middle portions of the Gakona and Chistochina Rivers. During the spring migration, females moved from th~ Lake Louise flats to the calving grounds in the eastern Talkeetna mountains. Migration occurred over a wide area, with some caribou uti 1 izing the Sus itna River in the upper area of the proposed Watana impoundment as a travel route. A small potion of the herd appears to cross be- tween Deadman and Jay Creeks. None of the area utili zed for calving will be flooded. The fall dispersal and mating period occurr~ed as the caribou moved o .. ut of the Talkeetna Mountains, across the Lake Lou1se flats anti into the Alphabet hills and \"iestward. (vi) Moose (To be written following receipt of report from ADF&G) 7-21 ,., •. -<! i I. .,_., __ ,._Jr'"" ..... . "(b) Furbear:ers .;......;;.;..;..;..;;....;;..;;;..;, __ The major furbearer species inhabiting the project area include red fox, coyote, lynx, mink, pine marten, river otter, ·short-tailed weasel, least wease1, muskrat and beaver. Red fox and pine marten are the most heavily trapped of the species; coyote and lynx are not common in the area-. Foxes were found to utilize the shores of the Susitna River and deltas of tributaries during summer and autumn, and alpine zones in the winter. All fox dens located were found above the area to be f1ooded by the proposed impoundment. Pine marten are abundant in t;he study area. They utilize areas both inside and outside the impo~ndment zone, including closed forest areas and open white spruce forests. Upstream from Gold Creek, most beaver and muskrat activity was found on plateaus between-2,000 and 2,400 feet above the river valley. No active beaver lodges or bank dens were found on the Susitna River upstream from Devil Canyon or on the lower reaches of the tributaries in this area. Furbearer activity increases progressively downstream from Devil Canyon. As the river becomes more braided, there is a marked increase in the number of beaver using the river, with the highest concentrations occurring south of Montana Creek. Short ... tailed weasels are common .and locally abundant in the study area; little information is available on least weasels. (c) Birds and Non-Game Mammals A total of 132 species of birds werP recorded in the Upper Susitna Ri'ler Basin study area.. The most abundtmt ~pecies are cam111on. redpoll, savannah sparrow, white crowned sparrow, 1 <.\~~:and l ongspur, and tree sparrow. Fourteen species are rare in the re.gion but are found in larger populations in other areas of A1 ask a. Generully, the forest and woodland habitats support higher densities and/or biomass of birds than the shrub communities. Areas of upland cliffs and block-fields and of mat and cushion tundra have the lov1est bird usage but support species not found in other habitats. The ponds and lakes in the basin support relatively few water birds.. The most abundant waterfowl species are scaup spp., American wigeon, goldeneye spp., mallards, and buffleheads. Trumpeter swans nest on a number of lakes, but none within the impoundment zone. Ten golden eagle, six bald eagle, and four common ravin nests are located within the study area, while two bald eagle and fcur golden eag·le nests occur within the impoundment zone. No endang_ered species (the ba1 d eagle is not endangered in Alaska) are known to occur in the study area. Sixteen species of small mammals are found in the upper Susitna ·Basin, the most abundant being the northern red-backed vole and the masked shrew. "-" ' .. -:---~ ::;:. 'I --~ ~ "· I 'I I I I I I 'I I I I I I I· I I ,I I I I I I .I I I I I I I I I I I I -, I I Arctic ground squirrels are abundant in well~drained tuhdra habitats throughout the high country~ Collared pika and hoarymarmots are relative- ly common in rock habitats above the tr.eeline. Red squirrels and porcupine are found in forests and woodland habitats. 7~8 -Botanical Resources The Upper Susitna River Basin is located in the Pacific Mountain physiographic division in south-central Alaska. The Susitna River drains parts of the Alaska Range on the notth and parts of the Talk?.~tna Mountains on the south. Many areas along the river in the upper basin are steep and covered with coniferous, deciduous, and mixed coniferous and deciduous forests. Flat benches occur at the tops of these banks and usually contain low shurb or woodland conifer com- munities~ Low ~~untains rise from these benches and are covered by sedge-grass tundra and mat 2nd cushion tundra. (a) Habitat Types The .vegetation/habitat types found in the upper basin (above Gold Creek} and fl~odp lain downstream to Talkeetna are c 1 assi fi ed and mapped according to the Alaska Classification System. The major vegetation/habitat types found in the upper river drainage are low-mixed shrub, woodland and open black spruce, sedge-grass tundra, mat and cushion tundra, and birch shrub. These vegetation types are typical of vast areas of interior Alaska and northern Canada, where plants exhib1t slow or stunted growth in respo~se to cold, wet, and short growing seasons. Deciduous or mixed coniferous forests which, by contrast, have more robust growth characteristics, occupy less than 3 percent of the upper drainage. These types occur at lower elevations, primar·ily along the Susitna River, where longer seasons of growth and better drained soils exist; they are more comparable to vegetation/habitat types occurring further downstream on the floodplain. The downstream fl oodp 1 ai n (be 1 0\'1 De vi 1 Canyon) vegetati on/habitat consists primarily of mature and decadent cottonwood forests, birch-spruce forest, alder thickets, and willow-cottonwood shrub communities. The willow cottonwood shrub and alder communities are the earliest to establish on ne\oJ gravel bars, followed by cottonwood forests, and, eventually! birch-spruce forest. Wetland areas~ ponds~ and lakes are present only in limited amount~ within the impoundment area. Table 7.21 lists the area of each habitat type present in the Upper Susitna Basin. Table 7.22 lists the area of each habitat type \'tithin the impound- ment zones and borrow areas. (b) Floristics A total of 246 p 1 ant species in 130 genera and 55 f ami 1 i es were found in the upper basin and floodplain areas. Families with the most species are Compositae, Salicaceae, Rosaceae, Grimineae, Cyperaceae and Eriecaceae. 7-23 --~;--li!W1 .. : ... j (c) Endangered Species No plant species occurring in Alaska are listed as endangered by federal or state authorities. None of the species under cons~de~ation for list1ng were found in the project area. 7.9 -~istoric and Archaeological Resources Surveys conducted located 43 archaeological sites within the area to be affected either directly or indirectly by the Watana Dam impoundment. These sites were found to represent human occupation dating from approximately 10,000 B.C. in the following culture periods: Jlmerican Paieoarctic, Northern Archaic Tradition, Arctic Small Tool Tradition: Late Prehistoric Athapaskan, and Historic. All of these sites are believed to be eligible for the National Register of Historic Places. Three historic sites, all cabins built in the 1920s, occur in ths Watana impoundment area. All three appear to be eligible for inclusion in the National Register. The Devil Canyon impoundment area includes seven arch~eological sites discovered during this study. These sites, representing varions time periods in Alaska prehistory including the American Paleoarctic and the Northern Archaic Tradi- tion, are all believed to be eligible for the National Register. One historic site, also a cabin believed to be constructed in the 1930s, lies within the Devil Canyon impoundment area. This cabin is believed to be eligible for the National Register. 7.10 -Socioeconomics Three areas are discussed to depict the socioeconomic settling of the project. These areas are: -The state of A 1 ask a; -The Railbelt region which includes Anchorage, Kenai-Cook Inlet, Seward, Valdez-Chitina ... Whittier, Matu.nuska-Susitna, southern Fairbanks, and the Yukon- Koyukuk census divisions; and -The local region of the Matanuska-Susitna Borough and the Valdez-Chitina- Whittier census divisions, and selected adjacent communities. I :I I I I 'I I I I -,I I ,I (a) State I The state of Alaska has -experienced steadily increasing populeation si:rtc~e the 1940s, with accelerated growth during the 1970s. Current popul~·r.,:on is 1· approximately 400,000, with approximately 50 percent located in the Jreater Anchorage area (Figure 7.30). Emplo}ment in Alaska rose d1ramatically during the construction of the I Trans-Alaska Pipeline System and has since leveled off; emplo)111ent in 1979 equaled 166,400. Government is the largest employer in the state, respon- sible ft.Jlr 33 percent of all jobs in 1979. Service industry emplo}1Tlent has .•.. increased recently, as has employment in transportation~ communication, . uti.lities, retai 1 trade, finance, insm•ance, and real estate. Unemplo.}fflent I 1-g4 1 I• ··I I I I I I •• I I I I I I I I I I I I I is typically higher in Alaska than in the lower 48 states; ths highest rate is associated with the native populations (Figur·e 7.30). Per capita personal income in Alaska·rose from $4,638 in 1970 to $10,254 in 1976, and then rose more slowly to $11,150 in 1979 (Figure 7.30). (b) Region The Railbelt region of Alaska contained 70 percent of the state•s popula- tion, or approximately 285,000 people, in 1980. This is an increase from 200,230 in 1970 (Figure 7.30). Emplo}Uient trends in the Railbelt region have been similar to overall trends, but there has been a higher share of emplo_>ment in the service.s and support sector and a lower share in producing sections of the economy (Figure 7.30). Per capita personal income ro5e from $4,940 in 1970 to $11,245 in 1976~. then stabilized. 1978 per capita personal income in the Ra.ilbelt region was $11,522 (Figure 7.30). (c) Local Increases in population between 1970 and 1980 in the Mat-Su Borough (175 percent) and the Valdez-Chitina-Whittier census division (71 percent)·were far higher than the stat~ average. Population levels stabilized as the Trans-A1 ask a P.i pe 11ne was camp 1 eted. The Mat-Su Borough's population rose steadily from 6,500 people in 1970 to 18,000 in 1980. Most of these peop 1 e reside in the souther.n quarter of the Borough. Palmer and Wasilla are the largest communities, with populations of approximately 2,100 and 1,550, respectively. Wasilla experienced an extraordinary growth rate of 510 percent during the past decade. Other population centers in the Borough are Big Lake, Esk aS_utton, Houston, and Talkeetna. The Valdez-Chitina-\~hittier census rose from 3,100 ·in 1970 to approximately 13,000 during 1976 as work on the TAPS pipeline peaked and then tapered off. The 1980 population was estimated at 6,225 (consistent demographic information is limited because of the alteration of this census division designation in 1980). Two trends are notable: -Native population has represented a significant portion of total popula- tion (22 percent in 1970); and -Population, along with economic activity in communities along the high- ways in this division, has declirfed since the opening of the Parks Highway in the early 1970s and the subsequent lessening of the traff1c along the. Richardson Highway (Figure 7 .31). Virtually all employment in the Mat-Su Borough is government, service~ and support sector oriented. Tot a 1 emp lo.Yffient has risen steadi 1 y from 1,145 in 1970 to 3,078 in 1979, an increase of 169 percent. However~ the Borough ;) 7-25 -. 1 l consistently has had high unemployment rates (20 percent in 1970 and 13.8 percent in 1979), often the highest in the state. Emplo)1Tient opportunities have not kept pace with the growth of the labor force. The Borough is more dependent on sea<;onal emplo)111ent than larger population centers such as Anchorage. - Resident civilian emplo)tnent in the Valdez-Chitina-yJhittier census division also rose steadily in the 1970s from 831 in 1970 to 2,180 in 1979, an i ncn~ase of 162 percent.. State/ 1 oc a 1 government and transportation/ communications/utilities represent the larg~·st sources of emplojfllent. rne latter includes emplO.Yffient associated with operation and maintenance of the petroleum pipeline. This census division tends to have unemployment rates slightly higher than state averages (Figure 7.31). Nominal personal income rose substantially in the 1970s, stabilizing as the TAPS pipeline was completed. In the Mat-Su Borough, per capita income rose from $3,957 in 1970 to $9,032 in 1977 and declined slightly to $8,878 in 1979. In the Valdez-Chitina-Whlttier census division, the boom experience of the 1970s is even more prominent. In 1970 the per capita personal income of $3,822 was similar to the Mat~Su Borough level; with construction of the oil pipeline, per capita income jumped to $21,544 in 1976 and then fell dramatically over the next few years. In 1979, per capita income equa 11 ed-$9,145 (Figure 7 .31). 7.11 -Recreational Resources Recreational activities currently available in the Upper Susitna Basin are those associated with undeveloped facilities. Hunting, fishing, hiking, and camping are the primary recreational uses, along with boating on the lakes. There are no publicly developed recreation facilities in the project area. Private facilities include three lodges: Stephen Lake Lodge {10 structures}; High Lake Lodge (9 structures); and Tsusena Lake Lodge. Those lodges are used as bases for fishing, hunting, skiing, boating, and hiking. Access is primarily by air. There are no developed facilities in the impoundment areas, nor are there any areas in the vicinity of the project that are included or designated for inclu- sion in the National Wild and Scenic River System, the National Trails System, or· a federal or state wilderness area. 7.12 -Aesthetic Resources The Upper Susitna River Basin comprises a diverse landscape composite, roadless and relatively uninhabited. The combination of these factors creates a large region that is aesthetica11y renowned for its natural beauty, where, dependi'ng upon a viewer's location in the basin, a variety of visual groupings free from man-made structures are ·dvai lable. Compared with other areas in Alaska~ the aesthetic resources of the project area are, typically, not seen as outstanding, but because the area ~, s a wilderness region positioned between the two major popu 1 ati on centers of Fairbanks and Anchorage, the aesthetic resources of the Upper Susitna Basin are important. 7--26 I AI I I I I I I I 1.· I I I I I ·I I I I (/ I I I I. I I· I I I •• I I, I I I I I I I. The Upper Susitna Basin offers aesthet~c diversity created by the juxtaposition of vegetation, water, and topograph i ca 1 features. The 1 and forms of the area are defined by three major elements:. the deeply incised Susitna River Valley and its tributaries, the Northern Talkeetna and Chulitna Mountains, and the Northern Talkeetna Plateau. The area~s dominating landform is the Plateau4 Its features, textures and relief, northeast trending, rounded low mountains, and highlands of generally rolling terrain slope to meet adjacent landforms that are moderate 1 y rugged, higher, and more mountainous. The remaining 1 and form types fall in the eastern project area and reflect the influence of the adjoining· Copper River Basin. These landforms are characterized by lower mountains and hills widely spaced·on the Plateau, and flat terrain interspersed with numerous ponds. Vegetation is diverse and vari~s with elevation. A dense spruce-hardwood forest blankets the lower drainages and slopes, while vast meadows of tundra cover higher elevation~. A variety of shrubs prc·Jides the transition between the two biomes, adding texture and color to the setting. This diversity of vegetation 1 ends itself to the natural occurrence of edge effect found in the more scenic visual groupings. Color enhances the scenic composite, particularly in autumn when the leaves of deciduous trees turn to golds and oranges, in direct contrast to the dominating dark spruce green. Also in the autumn, the tundra bursts into its brief bloom, adding color to the landscape. The deeply cut canyons and gorges of the Susitna River scenically exhibit the river's extraordinary power; the gorges are particularly striking at Devil and Vee Canyons where turbulent rapids, rock outcroppings and cHffs, and enclosed wa 1 1 s dominate the scene. The c 1 ear, wild, and seen i c mountain creeks are aesthetically stimulating; many of them rush over and through steep rocky embankments to form waterfalls. Lakes are numerous in the basin, ranging from small~ irregularly shaped lakes in the midst of park-like woods and mountain peaks, to a complex of five finger-shaped lakes set in a black spruce and shrub wetland region. Viewpoints over 1 ooki ng tht: project and adjacent area which are found atop the the higher mountain peaks include Deadman, Devil, and Chulitna Buttes, the ridges above Vee. Canyon, and B\g SvJimming Bear Lakes. On clear days, the scenery includes. extensive views of the Centra 1 Talkeetna r~untains and the Alaska Range, focusing. upon the often spectacular views of rvtounts r~cKinley, Deborah, and Hess, and the Eldridge, \~est Fork, and Susitna glaci.ers. 7.13 -Land Use Existing land use in the ar:ea is typical for that of interior undeveloped Alaska. Broad expanses of wilderness areas are present with minimal man-made developments or structures. Abandoned cabins and recreational 1 odges are the primary man-made structures. Significant concentrations of residences, cab1ns, and other structures occur nehr other lakes, Portage Creek, High Lake,·Gold Creek, Stephan Lake, Clarence Lake, and Big Lake. Oog sleds and all-terrain vehicles are used as modes of transportation in the area. There is l itt 1 e 1 and management in the area. Most 1 and in the project area and directly south has been selected by native corporations under provisions of the· Alaska Native \:)aims Settlement Act; lands to the north are generally managed by the U.S. Bureau ttf Land Management. 7-27 - -.. TABLE 7~1: TYPICAL NOAA CLIMATE DATA RECORD Meteorological Dafa For The Current Year Stotlt>n: SllKI'IT1 AUSKA • ~Ul<\ SUHIU! AIRPORT Srand .. d tln>t U>l!d: utltucle: 63' 20' II l:ongir.•de. 1~9 • 01 • II - lempout'"• 'F 0ogrHdi1VS 1\ver.ogn e~u-e~se 65 °f Muuth - e E ,._ l >.~ fi J I ~ .r >-r: ., ~ "i § ~! ~.£ £ f. ;;; ! DE 0 0 --·-_ .... ~ ----~ JAH '·" •3.11 4!.6 )4 30 "'26 " 1931 0 FF.II ~.z •10,'\ -3.1 )3 !I -28 ll 1975 0 It &II. 111,?. z.z lO,l! 30 6 -H u 1696 0 APR 36.1 14.5 25,4 " 30 -3 1!1 lliO 0 "~y ~),1. ,4!9,4 J6,, '" l l7 7 en 0 JUtt 60.,. 40.9 ,o .. t 14 27 ]4 II ltZO 0 JilL U.l ~3.6 !12.9 1& 23 )) 6 ~68 0 AIJG 62,11 ~··· ,2,3 71 l 31 29 lU 0 SIP 49,11 )l•l 40,1 59 14 16 30 7111 0 DCT YfAII I - T Temper;,tU<.,.'F NOt mal , ___ Oeg.ee d•vs Nuunal blfltfnet 0ASe65"F ~ e >-.r ... ,.il .s il s ,...!i l!i ~ :§ § a~ ::~; c ~ : 8 0 • Js :li lle :l;. a:::z >->-X. __.;. ---·-~--·-1-----1-·-1---Ia I :u :u ,J 7.9 -··· 1.6 "' L9U .,, 1971 1965 0 F u.ll -·4 6.6 45 ·~z " 1941 1633 0 tl 19·4 ]oO 11.2 49 9U ]!I 1971 1661 0 A 1~ •• 14•1 u.s n 1956 •30 19~4 124!1 0 ·~~ 4!1.7 29·1 37.4 76 960 H 19fo5 &56 0 J sa.o 19·9 4?.0 19 1961 H i9H uo 0 J t.o.z 4)ol sz.o 11 961 :n 1970 40) 0 A !16.0 4lol 4!.6 u 968 20 19!15 '01 0 s ,,1.1 32·6 39.9 lS 951 6 1956 7!1) 0 0 10,4 17·5 24.0 !l'i 969 15 l9'n Ul1 0 " u.J ,,.., ,,.., "' 962 7.9 19~11 16" 0 D 9.2 -1·4 z,9 4t1 969 0 Uli ·-·-·- Pleciplt•tlon in inches -··- W11er equivalent Snow, Ice pell«cs J: J: gl! ic '! Q.C:: ! "! j'" :t 0 e-... 0 ~ .. ~ ..,.,. 0 t-0 f--· - ~.11 1ol!' U-19 <\9,7 21.5 ll•l9 loll 0.5(1 " 19,6 e.7 !1•6 1.65 0.45 3-4 ... ,.1 a,, , o.H o.o11 26 '·' l.l Z6 2,98 1.90 • ll,l 2.6 • o.sa Q,,)O )0 o.o o.o t.os o.:n n o.o o.o 0.96 o.;zo 1 o·.o u.o 1.51i 0.411 9 o.• 0,3 lO ·-fl•l•tlve hultlidity, ret. §--t~ t-"' ~~ ci£ rT:r1 & ~ ~ & n ..... X X X X ·- 15 02 01 H 20 :i lltiCMtlmcl n c---·- 6l lO 73 'rl 6' 63 61 75 67 61 69 69 ill 1111 16 Fost"l milt -· ,. -.. --- c .2 1~ g ~ 0 ll .. --~ -·- u 2) 30 )1 01 23 , Ol 11 20 011 H 11 l~ u ll H l"l n u n ~0 26 1 Z!l 25 19 lO 01 12 . :0 g c. !! li ·-uii ~ c ~il - 6,0 3.9 -e.o 6.2 T.s 6,9 ••• 7.6 ll ll ~ • 5 6 ] J Normals, Means, And Extremes -ntllOUGII l97SI " ----. ---· _______ _, -· ·-,..,._. .. _,.,;W""" l'toc~•lt . Woter equlvalmt E ,.. e,. .. ~-,_ E .~ = e~ : l ~~ ig >->- allon In lnehol alive W'HKI 'ty JM;I, ~ -I , fa11011 tnllo il & I .. 2i X I l ~i j 1tt 20 lil!. r~ g 0 ci ~ ti lllmol • ci : !i E 1'6 e Ci > ... flel lcumldi ·----r--1-----:JS 35 1 6 I 5 1 l 0.91 3.38 l'HI 0,09 I"' I,ZJ 4.31 9!11 i lUO 1.04 ~.!1] 946 o,ol 1.961 0.67' "·"' 19M• 0,06 1944 11.7'1 2.66 1966 o.o~o '"'~ 2.19 "·"' t9n 0,41 l9U 69 611 1!1.1 HE 4~ 0!1 J968 lS 76 ll.9 HE fo6 07 19'14 70 ll n:1 HE "' 10 1971 65 7!1 7.6 UE n oe 1971 !II 67 7:7 w 21 Ol 1969 " 65 1.) Sll 29 22 1"0 0,10 lllU 6~ •• 191,11 16,] 197) 61 611 i.79 19'1 44•' 19!11 ze.o 1964 76 1' 1.61 lli4' !19,1 1'46 11.1 1946 76 76 0,97 196) U~l 1970 9,7 196J 10 75 0.96 19U n.~ 1958 7.5 lt46 n lO 2.l2 1.967 9.~ 1974 11.7 1'7' Qo\ H 3.09 !I.!IG 195'1 i.ll 195!1 3.10 6,33 "''5 0.70 ltH z.u 6.\3 1965 o.n 1969 1.62 ).79 t9.5l o.u: 1967 l.l'J ~.a, 951 0,06 1961 1.20 ,,6) 951 o,H t"'H 6Z n lal 511 ~0 2) 1'174 62 76 7.4 Sll 31 n 1975 '' 7!1 7;5 liE 32 2) 1972 76 81 a.o liE 35 Zl 1970 78 79 U.l HE ]9 u 1910 16 17 tz:1 liE .. ~ ll 1970 l,U 1941 9.7 1910 9.1 1970 t9 78 z.to l9H 9:o 195'1 6.0 19,!1 18 II z.ol ,, .. u.!l 19511 H.o 1955 u 81 1.24 l96J '"~· t.9ln 12.6 1970 IJ ., 1.10 l9t>4 ,,.1 tt6l Z1,9 197(1 19 79 1,09 1961 50.7 tUn n.'\ l'JO 16 71 IJG ~n "'ril HDV Ff8 ""' ' 4 t, II 6 I l ' t 5 il _:s -. !i·~ :fa ·--l s.z T.o 6o2 7,2 ,,, 11.2 8,2 8.) '7.4 7.6 7.1 6,!1 ElevAuoo l!)'ouudl: 21117 '""' 16 a 21 i4 lO t6 Z1 ll 12 1 ll ., 7 4 H u u Nnnll"" ul tl•v• l 6 • 2 ' 0 0 0 0 0 0 0 0 0 0 0 0 2 " ' 0 -~-----------·------- M .. n nurnber of d•vs 3 6 9 5 ] t ' 1l 5 ll 6 16 1 u ~ 19 6 2Z 9 10 10 1 7 12 4 ' ' ~ 2 1 0 0 0 0 • z Z 1 lZ 16 • 2 l 6 Zl 18 0 • ~ ' 20 16 2 • ' ' 21 lJ l 0 l ., 19 9 !I 0 9 ' 17 ll 6 0 • l l l l 1 'il\.4 911.1 ttl.z . 9l?.9 9Uol 92 ... 7 VII :u. 0 u.o 25.5 n 961 43 ~::1 ~ 1.925 I '""' ,1971 4368 0 20.06 6.7 .. ''" T 19~0 :.79 1951 n. t 1t67 zr;,o l'J64 Ill 76 &l 14 9,7 liE 41 10 1971 7.2 6ll 1o zn ne ~1 ' 12 9 n, U,\ '" ~U.tl - (~) l1mgth or record, years; through the current ye•r unlelS othen~lse not~, b&Sed 11n Jinuary dill. (b) 70' 1nd ihi)Ye 1t Alubn statiO(;s. • less than ene half. T Tn1ce. --- ,NORIW.S -Basld on rrcord for the I.Q41·1970 period. DATE Of AA EXJRUI: -lhe IROst recr:nl In cases of tlfolltlp1e o~currence, PREVAiliNG WINO DlkECHOll -Retard through l9lil. IIIHD DIRECTION -N~rlls Indicate tPnS of d~grees dotbdse fi'OIIt true north. 00 Indicates cala, fAST£S.I l!llE llliiO -Speed is .fntest llbsei'Yed l·11ln11te v1lue llhen the dlrectton Is 1n tens of' iletr·ees. ------ NOTE: Due to lc!ls than full ttrne opcrctlon on a variable achedule, rnnnunlly re~ord~d ~tlcuoelllil 1ne fr0111 broken sequencc11 Jn tncl)laplete t'<'t:l>rdR. llnily leillperaturc extn<IUI!If Rod predphft~h\t\ "' totals fm; t>Ortlcna: of the record may be for other dum a calc.>ndllr day. lh<" {lf!rlod of rc .. "'rd Cor 11oaoc elt:meuta h for other thnn consecutive yen~:;11. - ~ For calcnaar day prior to \968. @ Fot the perS,otl 1950-1954 and January 1968 to date lollum avaJlRble for Cull year. . . . t Fen• the j>erlod l9lt2-1953 and .Janunry 1961\ to date \d1en avallahle ,(or full year. I Data for this :st11tion not avaJlahle Ior arc:hlvlng nor publ.lcatlon of l'llliiMr.y effective October, 1976. ·-·-,-•. --- -·----· .. ----· .. ·------·- 0 TABLE 7 .2.: MONTHLY SUMMARY FOR WATANA WEATHER STATION DATA TAKEN DURING JANUARY 1981 Res~ Res. Avg .. t-tax. Max. Day's Max. 1-hn. Mean w~nd W1nd Wind Gust C.ust Mean Mean Solar Temp. Temp. Temp. Dir. Spd. Spd. Dir. Spd. P'Val RH DP Prec1p Energy Oa.~ Day Deg C Deg C Deg C ~-M/5 M/S M/5 Deg Dir. 01 Deg c MM WH/SQM tO 01 3.4 0.4 1.9 071 5.7 5.9 065 14.6 ENE 37 -11.7 o.o *** 0: t; 02 2.2 -1"1.6 -4.7 083 1. 5 1. 7 084 5.7 E AS -15.6 o.o *** 02; 03 -2.4 -13.3 -7.8 074 3.5 3.7 Oo1 8.9 £ 41 -18.3 o.o *** 0'} 04 -4.3 -9.0 -6.7 058 2.5 2.6 058 7.0 NE 49 -15.0 0.0 **·• 04t 05 -5.8 -11.8 -8.8 074 2.2 2.4 081 5.7 E 51 -18.3 0.0 ***' Q>, 06 -3.6 -10.·9 -7.3 068 7.2 7.3 077 14.6 ENE 37 -'18.0 0.0 *** {)6: 07 1.2 -4.8 -1.8 064 5.0 5.3 076 12.7 ENE 33 -16.0 0.0 *** 01' 08 -2.2 -9.4 -5.8 072 2.3 2.4 071 7.6 ENE 45 -15.9 0.0 *** QQ:) 09 -1.5 -6. 7 -4.'1 059 5.2 5.3 077 12.1 ENE 30 -19.1 0.0 *** 09=< 10 -1.8 -9.2 -s.s 059 4.0 4.1 073 11.4 ENE 45 -14.8 0.2 *** lQl 11 -1.1 -5.1 -3."1 062 4.8 ·4.9 075 10.8 ENE 47 -13.3 0.0 *** 11; 12 -1.9 -9.2 -5.6 053 2.0 2. '1 071 7.6 ENE 48 -14.1 0.0 *** t~ 13 -1.2 -9.9 -5.6 049 3.8 4.2 099 12.7 Et\E 33 .-.'18.3 0.0 *** 1'~ 14 3.4 -3.5 -o.o 061 5.3 5.6 075 '14.0 ENE 46 -·JO.O 0.0 *** 14, 15 3.5 -0.9 1"3 079 3.2 4.1 081 1.2.7 ENE 51 -7.3 0.2 *** l~ 16 0.1 -5.7 -2.8 050 2.9 3.2 071 12.1 ENE 45 -13.6 o.o *** l~ 17 0.9 -2.4 -0.8 060 4.2 4.4 062 12.7 ENE 35 -15.'1 o.o *** 1'7' 18 0.9 -3.6 -1. 3 068 4.8 5.0 074 14.0 ENE 35 -14.3 0.0 ***' lSI 19 1.3 -6.5 -2.6 109 0.4 3.9 242 13.3 ENE 40 -14.2 0.8 *** 19! 20 -5.8 -'13.6 -9.7 062 4.3 4.4 075 8.9 ENE 30 -20.3 0.0 *** Ztt 21 -4.8 -12.6 -8.7 057 5.0 5.1 078 9.5 NE 35 -20.1 0.0 *** 2:.tl 22 -'1. 1 -5.3 -3.2 052 4.9 5.0 083 9.5 NE 34 -16.7 0~0 *** z:i'l ~ 23 1.4 -5.1 -'1.9 061 4.5 4.8 003 11.4 NE 40 -13.8 0.0 *** 2:~ 24 -0.1 .... 5.0 -2.6 048 3.5 4.0 055 10.2 ENE 30 -18.3 0.0 *M-* Z'~ 25 ·t.6 -3.9 -1.2 067 4.6 5.0 090 12.1 ENE 23 -19.2 0.0 *** 2:~ 26 -4.2 -8.3 -6.3 342 0.6 1.4 088 3.8 WSW 52 -14.3 0.2 *** 2:~ 27 -6.2 -14.4 -10.3 062 1.0 1.2 059 3.2 ENE 51 -17.8 0.0 *** 2:~ 28 -11.3 -17.7 -·14.5 065 4.S 4.6. 065 14.6 ENE 44 -23.7 0.0 *** z~ 29 -2.2 -12.3 -7.3 058 6.2 6.4 070 13.3 NE 38 -19.7 0.0 *** ~9 30 1. 7 -3.2 -0.7 068 5.7 5.8 075 12.1 ENE 26 -18.3 0.0 *** ~ 31 -0.1 -4.2 -2.2 053 a.8 2.9 045 7.6 ENE 38 -14.7 0.2 *** :n NO NTH 3.~ -'17.7 -4.5 062 3.8 4.2 085 14~6 tNE 40 --16.2 1.6 *** Gust Vel. at Max. Gust Minus 2 rntervals 13.3 Gust Vel. at Max. Gust Mwus 1 Interval 12.7 Gust Vel. at Max. Gust Plus 1 Interval 12. '1 Gust Vel. at Max. Gust Plus 2 Intervals 12.7 .. 'TABLE 7.3: SUMMARY Of CLIMATOLOGICAL DATA MEAN MONTHLY PRECIPITATION 1N INCHES PERIOD OF STATION JAN fEB MAR APR MAY JU.NE JULY APG SEPT OCT NOV DEC ANNUAL RECORD Anchorage 0.84 0.56 0.56 0.56 0.59 1.07 2.07 2.;32 2.37 1 .. 43 1.02 1.07 B1g Delta 0.36 0.27 0.33 0.31 0.94 2.20 2.49 1.92 1.23 0.56 0.41 0.42 11.44 1941 -70 faubanks 0.60 0.53 0.48 0.33 0.65 1.42 1.90 2.19 1.08 0.73 0.66 0.65 11.22 1941 -70 Gulkana 0.58 0.47 0.34 0.22 0.63 1.34 1.84 1$58 1. 72 0.88 0.75 0.76 11.11 1941 -70 Netanuska Agr. Exp. Stat1on 0.79 0.63 0.52 0.62 0.75 1.61 2.40 2.62 2.31 1.39 0.93 0.93 15.49 1951 -75 ~1cKinlev Park 0.68 0.61 0.60 0.38 0.82 2.51 3.25 2.48 1.43 0.42 0.90 0.96 15.54 1951 -75 Summ1t WSO 0.89 1.19 0.86 0.72 0.60 2.18 2.97 3.09 2.56 '1.57 1.29 1.11 19.03 1951 -75 Talkeetna 1.63 1.79 1.54 1.12 1 .. 46 2 .. 17 3.48 4.09 4.52 2.54 1.79 ·t. 71 20.64 1941 -70 . MEAN MONTHLY TEMPERATURES Anchorage 11.8 17.8 23.7 35.3 46.2 54.6 . 57.9 55.9 48.1 34 .• 8 21. '1 13.0 1941 -70 Biq Delta -4.9 4.3 12.3 29.4 46.3 57.1 59.4 54.8 43.6 25.2 6.9 -4.2 27.5 1941 -70 . fairbanks -11.9 -2.5 9.5 28.9 47.3 59.0 60.7 55.4 44.4 25.2 2.8 -10.4 25.7 1941 -70 . Gulkana -7.3 3.9 14.5 30.2 43.8 54.2 56.9 53.2 43.6 26.8 6.1 -5.1 26.8 1941 -70 Matanuska Agr. Exp. Stat1on 9.9 17.8 23~6 36.2 46.8 54.8 57.8 55.3 47.6 33.8 20.3 12.5 34.7 1951 -75 McK1nle~ Park - 2 .• 7 4.8 11.5 26.4 ll0.8 s1. s· 54.2 50.2 40.8 23.0 8.9 -0.1( 25.8 1951 -75 Summit WSO -0.6 5.5 9.7 23.5 37.5 48.7 52.1 48.7 39.6 23~0 9.8 3.0 25.0 1951 -75 Talkeetna 9.4 15.3 20.0 32.6 44.7 55.0 57.9 54.6 46.1 32.1 17.5 9.0 32.8 1941 -70 0 - - - - - - -.• -' •. - I I I I I I I I I I I I I I I I .I I I TABLE 7.4: RECORDED AIR TEMPERATURES AT TALKEETNA AND SUMMIT 1N °F 5iATIO~ Talkeetna Summl.t Da1ly Da1ly Monthlt Da1ly Dally Monthly Month Max. Hl.n. Average Max. M1n. Average Jan 19.1 -0.4 9.4 5.7 -6.8 -0.6 Feb 25.8 4.7 15.3 12.5 -1.4 5.5 Mar 32.8 7.1 20.0 18.0 1.3 9.7 Apr 44.0 21.2 32.6 32.5 14.4 23.5 May 56.1 33.2 44.7 45.6 29.3 37.5 June 65.7 44.3 55.0 52.4 39.8 48.7 Jul 67.5 48.2 57.9 60.2 43.4 52.1 Aug 64.1 45.0 54.6 56.0 41.2 48.7 " Sept 55.6 36.6 46.1 46.9 32.2 39.6 Oct 40.6 23.6 32.1 29.4 16.5 23.0 Nov 26.1 8.8 17.5 15.6 4.0 9.8 Dec 18.0 -0.1 9.0 9.2 -3.3 3.0 Annual Average 32.8 25.0 Month May June July August September SUBTOTAL TABLE 7 .. 5: PAN EVAPORATION DATA Average Monthly Plan Evaporabon, Inches Matanuska Valley Agr~cultur.al £xpans~on Stat~on Evaporat~on Years Recorded 4,63 '15 4.58 24 4.09 29 2o99 29 1.83 26 -- 18.12 0 Un1vers~ty Expans~on Stat:lon · Watana Cam~ Evaporation Years Recorded Evaooratlon Yearsecorded 4.46 5.09 4.50 2.96 1.42 18.43 19 26 30 30 24 3.6 3.6 3.3 2.5 1 • .5 14.3 1 1 1 1 I .I •• •• I· I I I I I I I I I I I I I TABLE 7 .. 6: AVERAGE ANNUAL AND MONTHLY FLOW AT GAGE 1: IN THE SUSITNA BASIN* I STATlON (USGS Reference Number ) Sus1tna River Sus1i:na R1ver Sus1tna R1ver t1aclaren R1 vel' at Gold Creek Near Cantwell Near Denall Near Paxson I (292or (2915) (2910) {2912) MONTH Dra1nage Area 6160 4140 950 280 sg. mi. IV Mean(cfs) .% Mean(cfs) % Mean(cfs) % Mean(cfs) 10 I JANUARY 1 1_.453 1 824 1 244 1 96 FEBRUARY 1 1,235 1 722 1 206 1 84 I MARCH 1 1 '114 1 692 1 188 1 76 APRIL 1 1,367 1 853 1 233 1 87 I MAY 12 13,317 10 7,701 6 2,036 7 803 .I JUNE 24 27,928 26 19,326 22 7,285 25 2,920 JULY 21 23,853 23 16,892 28 9,350 27 3,181 I AUGUST 19 21,478 20 14,658 24 8,050 22 2,573 SEPTEMBER 12 13,171 10 7,800 10 3,350 10 1 '149 I OCTOBER 5 5,639 4 3,033 3 ·t ,122 3 409 NOVEMBER 2 2,467 2 1,449 2 490 1 177 I DECEMBER 2 l '773 1 998 1 314 1 118 (' ANNUAL -cfs 100 9,566 100 6,246 100 2, 739 100 973 I Per~od of Record -Gold Creek -1950-79 I' Cantwell -1961-72 Denali -1957-79 Maclaren -1957-79 I * Ref. USGS Streamflow Data I I I I I I I I I I I I I I I I I I I I I I I YEAR 1950 1951 1952 1953 1954 1955 1956 1957 195B 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 OCT 6335.0 3848 .. 0 557j + 0 8202+0 5604.0 5370*0 4951.0 5806.0 8212 .. 0 4811.0 6558.0 7794.0 5916 .. 0 6723.0 6449.0 o291.0 7205.0 4163.0 4900.0 3822.0 3124.0 5288 .. 0 5847.0 4826.0 3733 .. 0 3739.0 7739.0 3874.0 NOV 2583.0 1300.0 2744.0 3497.0 2100.0 2760.0 1900.0 3050.0 3954.0 2150.0 2850.0 3000.0 2700.0 2800.0 2250.0 2799.0 2098.0 1600.0 2353.0 1630.0 1215.0 3407.0 3093.0 2253.0 1523.0 1700.0 1993.0 2650.0 7571.0 3525 .. 0 4907.0 2535.0 7311.0 ;4192.0 7725.0 3986 t 0 . * Long term average flows ·assumed DEC 1439t0 1100~o0 1900.0 1700.0 1500.0 2045.0 1300.0 21.42. 0 3264.0 1513.0 2200.0 2694.0 2100.0 2000.0 1494.0 1211.0 1631.0 1500.0 2055.0 882.0 866.0 2290.0 2510.0 1465.0 1034.0 1603.0 1081.0 2403 .. 0 2589.0 1681.0 2416.0 1773 .1~ JAN 1027.0 960.0 1600 .. 0 1100.0 1300.0 1794.0 980.0 1700.0 1965.0 1448.0 1845.0 2452.0 1900.0 1600.0 1048.0 960.0 '1400. 0 1500.0 1981.0 724.0 824.0 1442.() 2239.0 1200.0 874.0 1516.0 974.0 1829.0 2029.0 1397.0 1748.0 1453.6~ TABLE 7.7: GOLD CREEK NATURAL FLOWS FEB 788.0 820.0 1000.0 820.0 1000.0 1400f0 970.0 1500.0 1307.0 ·1307. 0 1452.0 1754.0 1500.0 1500.0 966.0 860.0 1300.0 1400.0 1900.0 723.0 768.0 1036 .. 0 2028.0 1200.0 777.0 1471 .. 0 950.0 1618+0 1668.0 1286.0 1466.0 1235. 6 ... MAR 7.26.0 7,10. 0 8BO.O 820.0 780.0 1100.0 940v0 L200.0 1148.0 980.0 1197.0 1810.0 140-0.0 1000.0 713.0 900.0 1•300 t 0 1200.0 1900.0 816.0 776.0 950.0 1823.0 1000.0 724.0 1400.0 900.0 1soo .. o 1605.0 1200.0 1400.0 1114.3}1;. APR NAY. JUN JUL SEP 870.0 11510.0 19600.0 22600.0 "19890.0 8301.0 1617.0 14090.0 20790.0 22570.0 19670.0 21240.~ 920.0 5419.0 32370.1 26390.0 20920.0 14480.0 1615.0 19270.0 27320.1 20200i0 20610.0 15270.0 1235.0 17280.0 25250.0 20360.0 26100.0 12920.0 1200.0 9319.0 29860.0 27560.~ 25750,0 14290.0 950.0 17660.0 33340.0 31090.1 24530.0 18330.0 1200.0 13750.0 30160.0 13310.0 20540.0 19800.0 1533 .. 0 12900.0 25700.0 22880.0 225~0.0 7550 .. 0 1250.0 15990.0 23320.0 25000.0 31180.0 16920.Q 1300.0 15780.0 15530.0 22980.0 23590.0 20510.0 2650.0 17360.0 29450 .. 0 24570.0 22100.0 13370.0 17oo.o 1259o.o 4327o.o zssso.o 235so.o 1sa9o.o 830.0 19030,0 26000.0 3~400.0 23670.0 12320.0 745.0 4307.0 50580.0 22950.0 16440.0 9571.0 1360+0 12990.0 25720.0 27840.0 21120.0 19350.0 1775.0 9645.0 32950.0 19860.0 21830.0 11750.0 1167.0 15480.0 29510.0 26800.0 32620.0 16870.0 1910.0 16180+0 31550.0 26420.0 17170 .. 0 8816.0 1510.0 11050.0 15500.0 16100.0 8879.0 5093.0 1080.0 13380.0 18630.0 22660.0 19980.0 9121.0 1082.0 3745t0 329>30.0 23950.0 31910.0 14440.0 1710.0 21890.0 34430.0 22770.0 19290.0 12400t0 1027.0 8235.0 27800.0 182~0.0·20290.0 9074.0 992.0 16180.0 17870.0 lBBOOcO 16220.0 12250.0 1593.0 15350.0 32310.0 27720.0 18090.0 16310.0 1373.0 12620.0 24380.0 18940.0 19800.0 6881.0 1680.0 12680.0 37970.0 22870.0 19240.0 12640.0 1702.0 11950.0 19050.0 21020.0 16390.0 8607.0 1450.0 1 :.S870 ~ 0 24690.0 28880 + 1 20460 + 0 10770.0 1670.0 12060.0 29080~0 32660.0 20960.0 13280.0 1367.~13316+7~18143.0 32000.0 38538.0 l3.171.1ti( - 1793.2 1462.8 1242.8 1123.2 1377.0 13277+4 27657.9 24382.8 21995.5 13174.5 7971.6 9062+1 9516.2 10035.3 9¢.19.1 1Q:;~Q4.0 11411+8 103 .. ~6 .5 9412.8 10489.1 9649.3 10750.3 11530.5. 10989.4 9792.8 10116.8 9395.3 11150.8 9761.3 5560.8 7535.3 10205.8 10835.8 8051t7 7581.4 10233.5 8135.9 10079.5 8142.2 9427+2 10686~9 11152.0 9651.0 I I I I •• •• I I I I I I I I I I I I ,, TABLE 7.8t WATANA ESTIMATED NATURAL FLOWS YEAR OCT NDV DEC JAN FEB Nt-1R APR M~1Y JUN JUL. AUG SEP 1950 4719 ~ 91 2083.6 1168.9 815.1 64i + 7 569.1 680.1 8655.9 16432.1 19193.4 16913.6 7320.4 1951 3299.1 .1107 t 3. 906.2 808.0. 673.0 619~8 1302.2 1:1.6~9.8 18~:r·J-/ 0 -~v,1 ... •~" +< 19786.6 16478.0 17205~5 1952 4592.9 2170.1 1501.0 1274.5 841 + 0 735.0 803.9 4416~5 2S773 .. 4 22110.9 '1 -, ..... C"' l_ .... .~. ,· .::) .J a • ;:. 11571.0 1953 6285.7 2756;8 1281"2 '818.9 611.7 670.7 1 ..... 0 '""> 0 ~v,:.,+ lS037~2 21469.8 1731:':;.': •-z ,· "'")~, ... 16681.6 11513.5 1954 4218.9 1599t-6 1183.8 1087.8 80~.1 638.2 942.6 j:J696.8 19476.7 16983.6 20420.6 9165 .. 5 1955 3859.2 2051.1 1549.5 1388+3 1050.5 886.1 940.8 6718.1 24881.4 ..., ..... ""187 9 23537.0 13447.8 .;;.. .::> /. . t• . 1956 4102.3 1588 ~ 1 1038.6 816.9 754.8 694~4 718.3 12953.3 27171~8 25831.¢ 19153.4 13194.4 . 1957 4208.0 2276.6 1707.0 t373.0 1189.0 9:55.0 945.1 10176.2 ')1:'")71:' 0 19948-t-9 :1.7.317.7 14841.1 ~.......... ,J •· . 1958 6034.9 2935.9 2258.5 1480.6 104:1..7 973.5 .1265.4 9957.8 22097.8 1075;? .... 18843.4 5978.7 .. ~ + / 1959 3668.0 1729.5 1115.1 1081.0 9·19.0 .~94.0 B85.7 :1.0140 it 6 18329.6 2049.3. 1 2:~910. 4 12466.9 1960 5165 + 5 2213.5 1672.3 1400~4 1138.9 961.1 1069.9 13044.2 1-'') ... 3 4 1 S'50(:q 1 19323.1 16085 ... 6 ~~~ + . 1961 6049.3 2327~8 1973.2 1779.9 1.30-1 + 8 13"~ 1 ; 0 1965.0 13637.9 •i"J'784 1 A!...~.( ' .. 198:~9. 8 19480.2 10146.2 1962 4637.6 2263.4 1760.4 .1608.9 1257.4 1176.~ 8 1457.4 1:t3:?.3.5 36017.1 23443.7 19887.1 12746.2 1963 5560.1 2508.9 1708.9 1308.9 1184.7 883 •. 6 776.6 15299.2 20663.4 28767.4 2.:011.4 1Qsoo .·o 1964 5187.1 1789.1 1194.7 852.0 781 .. 6 575.2 609.2 3578.8 42841.9 20082 .. 8 14048 t 2 7524.2 1965 4759.4 2368.2 1070.3 863.0 7?2.7 807.3 1232.4 10966.0 21213~0 23235.9 17394.1 16225 .. 6 1966 5221~2 1565 .. 3 1203+6 1060.4 984.7 ' 984.7 1338.4 7094.1 25939.6 16153.5 17390.9 9214.1 19.67 3269.8 1202.2 1121.6 1102.2 1031.3 889.5 849 t 7 12555.5 24711.9 21987.3 26104.5 13672~9 196.8 4019.0 1934.3 1704.2 1617.6 1560.4 ·1560 t 4 1576.7 12826.7 25704.0 22082.8 14147.5 7163.6 1969 3135.0 1354.9 753.9 619.2 607.5 686.0 1261.6 931.3t7 13962.1 14843.5 7771~9 4260.0 1970 2403.1 1020.9 709.3 636.2 602)1 624.1 986.4 9536.4 14399.0 18410.1 16263.8 7224.1 1971 3768.,·0 2496.4 1687.4 1097.1 777.4 717.1 813.7 2857.2 27612.8 21126.4 27446.6 12188.9 1972 4979.1 2587.0 1957.4 1670.9 1491.4 1366.0 1305t4 15973.1 27429~3 19820.3 17509.5 10955.7 1973 4301.2 1977.9 1246.5 1031.5 1000.2 873.9 914.1 7287.0 23859.3 1&351.1 18016.7 8099.7 1974 3056.5 1354.7 931.6 786.4 689.9 627.3 ·871 + 9 12889 .. 0 14780~6 15971~9 13523.7 9786.2 1975 3088 .. 8 1474.4 1276.7 "'111:' 8 111.0 ... 3 1041.4 1211.2 11672.2 26689.2 23.4:50.4 1G126.6 13075.3 .1. ~ ~ +' 1976 ,5679 + 1 1601.1 876.2 757.8 743.2 690.7 1059.8 8938.8 19994.0 1..,01~ ..... 18393.5 5711.5 / ;:.Jf . .:) 1977 2973.5 1926.7 1687.5 1348.7 1202.9 1110.8 1203.4 8569.4 31352+8 19707.,3 16807.3 10613.1 1978 5793.9 2645.3 1979.7 1577.9 1267.7 1256.7 1408.4 11231.5 17:277.2 18385 .. 2 13<i12t 1 7132 .• 6 1979 3773.9 1944.9 1312.6 1136.8 1055.4 1101.2 1317.93 12369.3 22904.8 2491:t.7 16670./1 9096.7 1980 . . 3 3525. o3 2032 • 0 3 1470 + 03 123:5. 0~ l t 77 + 0 3 10140.03 23400.0 26740.0 18000.0 11000.0 ·6150.0 1404.0 1981 6458. 02. -. ") 97 02 1385 + 0 4 1147. o4 971 .. o4 889.04 1103. ot;. 10406. o4-17323. o2 27840. o2 314 35. o2 12o26 t o2 ~..:.. t AVE 4513.1 2052.4 1404.8 1157.3 898.3 1112.6 10397.6 22922.4 20778.0 18431.4 10670.4 Notes: (1) Discharges based on Cantl'vell and Gold Creek flmrs unless specified (2) Watana observed flows (3) Flows based on Gold Creek (4) Watana. long term average flows asslJTied AVE 6599.5 7696.1 7745.5 7988f7 73~.!1 ~ 4 8674.8 9001.5 8349.4 7718(14 7957 7 ' .• J 7901 .. 2 gc-C'l . \Jv • 6 9799+1 9206.1 8255.4 8409t0 7345.9 n· 9041.5 7991.4 4880.8 6068.0 8549.1 8920.4 7079.9 I .") ]'J I:: 0..:. ~·;:s 8367.7 6788.4 8208.6 6947.;.4 8133t0 8855.9 9523.3 7943.1 I I I I I ·- 1 I I· I I I I I I It ·I TABLE 7.9~ DEVIL CANYON ESTIMATED NATURAL FLOWS ·- YEAR OCT • NOV DEC JAN FE:B MAF~ AF'f:: MAY JUN JUt AUG SEF' 1950 5758 .. 2 .2404-.7 -1342~5 951.3 735.7 670.0 802 ... 2 10490.7 18468+c6 21383.4 18820.6 7950.8 1951 3652.0 1231t2 1030 .. 8 905.7 7 6'1 + 5 697.-1 150.4.6 13218.5 19978~5 ntr-.r:-9 .:. .. -.)1 / 1-1 {, . 18530.0 19799.1 1952 5221.7 2539.0 1757.:5 1483.7 943.2 828~2 878.5 49B9t-5 30014t-2 :2-·'1861 (. 7 19647f2 13441 .. 1 1953 7517 .,~ 3')-."') I ,:.;~.:.+0 1550.4 999.6 .., 4""" 6 I r.J <H 7'6·' (;j t I -1531.8 l7758l3 .,s::-., .... o 7 .:... ..J .:. • ..,:, • 191H4+0 19207.0 13928.4 1954 5109t3 1921.3 1387.1 1224.2 929.7 729.4 1130~6 15286.0 23188~1 1915-'1t1 24071.6 11579.1 1955 4830 .. 4 2506.8 1s6n.o ].649.1 1<")-g:-. ., ~ ... " ,..J + .4--10~~3 ... ~ 1107 .. 4 8390 .. 1 28081 .. 9 2621~1\)8 "119t::0-6 L... .. ... ) ~~ f-1 70 89 ") . .._. .... . ' ·ti ._ 1956 4647.9 1788.6 1206~6 921.7 893.1 852.3 8t.7 + 3 J~979+0 31137.1 29212,0 22609~8 16495.8 1957 C'') .... C' 3 -.}~~.\} .. 2773.8 1986,.6 1583 .. 2 :1.388 ~ 9 t3 oL-:· ~ • \::J. )' 1.109.0 12473.6 '10'jC' 4 .:.. \.J 4 . \::J " • ...,,..} 100 6 ...:..J:_. -., .... 19389.2 18029.0 1958 7434.5 3590.4 2904.9 1792~0 1212+2 1085.7 1437.4 1:1849.2 24413~5 21763.1 21219v8 6988~8 1959 4402.8 1999.8 1370.9 1316.9 1179.1 877.9 1119.9 13900.9 21.537.7 23390.4 28394~4 15329.6 1960 6060.7 '")'l'l') 7 .:...0 . ..:::...:... 2011.5 1686.2 1340.,2 1112<-8 1217.-8 14802.9 14709.8 21739~3 22066.1 18929 .. 9 1961 7170 .. 9 2759.9 2436 t 6 2212.0 159.3 t 6 16.7S8.9 2405 .. 4 16030.7 27069.3 22880.6 21164.4 12218i-6 1962 5459.4 2544.1 1978.7 1796.0 1413.4 1320.3 1613.4 12141.2 40679.7 24990 ~-6 22241.8 14767.2 1963 6307.7 2696.0 1896.0 1496.0 1387t4 958.4 810.9 17697.6 24094.1 32388.4 22.720 .• 5 11777.2 1964 5998.3 2085.4 1387.1 978 .. 0 900.2 663~8 696.5 4046-~,9 47816.4 21926,0 155.85.8 8840.0 1965 5744 + 0 2645.1 1160 .. 8 925.3 8~~8 ~ 8 866.9 1314~4 12267.1 24110.3 2619!5.7 19789.3 18234.2 1966 6496 .. 5 1907 + 8 1-478.4 127.8.7 1187.4 1187.4 1619 .. 1 8734.0 30446.3 18536.2 20244 + 6 10844(-3 1967 3844.0 1457.9 1364.9 1357.9 1268,.3 1089.1 1053.7 14435.5 27796.4 25081.2 30:293.0 15728.2 1.968 4585.3 ry~o3 ~ ..:.. .:.. . ;;;:} 1929.7 185.1. 2 1778(.7 1778.7 1791.0 14982.4 29462.1 2487j .o 16090.5 8225~9 1969 3576.7 1531.8 a:~6.3 686.6 681~8 769.6 1421.3 10429.9 14950.7 15 ~I" 1 ':) ~ o,~) .. + ~ 8483.6 4795.5 1970 2866.5 1145.7 810.0 756.9 70fi.7 721.8 1046.6 10721.6 17118.9 21142~.2 18652.8 8443.5 1971 4745.2 3081.8 2074.8 13l8.8 943..6 866.8 986.2 3427.9 3103160 229·4l.} 6 30315.9 13636.0 1972 5537.0 2912.3 2312.6 2036.1 1836~4 1659.8 1565.5 J9776.8 31929.8 21716~5 .18654.1 11884.2 1973 4638.6 2154.8 1387 .. 0 1139.8 11 ~~8) 6 955.0 986 •} 7 7896.4 263S>2+6 17571.8 1947~L. l. 8726.0 1974 3491 .. 4 1462.9 997.4 842.7 74~:.; + 9 689.5 949.1 j5004.6 16766.7 1.7790.0 15257.0 11370.1 1975 3506.8 1619 .. 4 1486.5 1408.8 13(}~ . .., \ ' ... .,. -4.,. 1271.9 j,456 + 7 14036.5 30302.6 26188.0 17031.6 15154·7 1976 7003 .. 3 1853.0 1007.9 896.8 876.2 825 .. 2 1261.2 11305.3 22813.6 18<")t:'~ 6 -~,J ...... 19297.7 6463.3 1977 3552.4 2391.7 2147.5 1657.4 1469.7 1361 .. 0 1509.8 11211.9 35606.7 21740.5 183/:1. (• 2 1:1.916.1 1.978 6936.3 3210.8 2371.4 1867.9 1525 .. () 148().6 1597.1 1:1693.4 18416.8 20079<-0 35326.5 8080.4 1979~ 4c~o., ..,. 2324.3 1549.4 1304.1 120:5\)6 1164-!7 l. 402 t s. 13334.0 24052.4 274.s2. a :1.9106.? 10172.4 . .;J ...:. + ..,:, 1980 6900.0 3955.0 227-9.0 1649.0 138:~. 0 1321 .. 0 1575 .. 0 11377.0 26255.0 30002.0 20196.0 12342.0 1981~ 7246.0 3699 .. 0 1554.0 1287 .. 0 1089~0 997.0 1238.0 11676.0 19436.0 312:36.0 ...-o;:--,70 0 ~ ..::J •• '.,C ..• 13493.() AVE 5311.8 2382.9 1652.0 1351.9 1146.9 1041.8 .1281.5 12230.2 25991.3 231.00.9 20709.0 12?99.2 * Discharges based on Watana flows AVE: 7481 .. 6 8574.2 8883.8 9304.4 8809y2 9657t-8 )II' / 10550.9 9633.3 8807.6 9585.0 9025.0 9965i-1 10912.2 10352.5 9243~7 9506.8 8663.4 10397.5 9129.2 5317.9 7011.3 9614.1 10151.8 7704 .. 6 7113.9 9567 .. 1 7654.7 9411~3 7715~4 8965.0 oo-6 "1 .. " ,:, + ....:_ 10685.1 9041.6 ·I ·~ :'.. I TAP' ,t 7.10: PEAK FLOWS Of RECORD I Gold Creek Canbvell Denall. Maclaren ( I I, Peak Peak Peak Peak 3 3 3 3 Date ft /s Date ft /s Date ft /s Date ft /s I 8/25/59 62,300 6/23/61 30,500 8/1.8/63 17,000 9/13/60 8,900. 6/15/62 80,600 6/15/62 47,000 6/07/64 16,000 6/14/62 6,650 I 6/07/64 90,700 6/07/64 5Q,500 9/09/65 15,800 7/18/65 7,350 6/06/66 63,600 8/11/70 20,500 8/14/67 28,200 8/14/67 7,600 • I 8/15/67 80,200 8/10/71 60,000 7/27/68 19,000 8/10/71 9,300 t 8/10/71 87:400 6/22/72 45,000 8/08/71 38,200 6/17/72 7' 100 I I I TABLE 7.11: ESTIMATED FLOOD PEAKS IN SUSITNA RIVER I Locat~on Peak Inflow 1n Cfs for Recurrence Interval 1n Years 1:2 1:50 1:100 1:10,000 PMF I Gold Creek 48,000 105,000 118,000 200,000 408,000 I Watana Dams~te 42,000 82,000 92,000 156,000 326,000 Devil Canyon Dams~te ) 12,600 43,000 61,000 165,000 366,000 (Routed Peak In flow ) I with Watana ) I I I I I TABLE 7.12: MAXIMUM RECORDED ICE THICKNESS ON THE SUSITNA RIVER Histor1cal Data Current Program Max1mum Ice Th.tckness Year of Max1mum lee Thlckness location Period of Record (Feet Observatlon Observed J.n 1980 (feet) Maclaren RJ.ver at Paxson 1960-68 5.2 I 1964 - Sus1.tna River at Cantwell 1962-70 5.3 1967 10.0 . Sus1.tna R1.ver at Gold Creek 1950-70 5.7 1963 3.2 Talkeetna Rlver at Talkeetna 1966-71 3.3 1969 - Chulltna fhver at Talkeetna 1961-72 5.3 1971 - Watana Dams.tte 1980-81 NA -5.0 Dev1.l Canyon 1980-81 NA -23.0* * Ice shelf th.tckness -not1ce cover. TABLE 7.13: SUSPENDED SEDIMENT TRANSPORT IN SUSITNA RIVER Average Annual Suspended location Sed.tment load (tons/year) Sus1.tna Rlver at Denali 2,965,000 Maclaren River near Paxson 543,000 Sus1tna River near Cantwell 6,898,000 Sus1tna R.tver at Gold Creek 7,731,000 I I I I I I I 'I I I I I I I ·I I I I I I I I I I I I I I I I I I I I " ::; TABLE 7.14: ESTIMATED SEDIMENT DEPOSITION IN RESERVORS Sed1ment Depos1t1on Trap SO -Year 100 -Year Efhcienoy Depositlon J~ of Reservou Depos1t1on % of Reservo1r Reservoir IV ac -ft Gross Volume ac -ft Gross Volume 10 Watana 100 240,000 2.5 472,000 5.0 70 '170, 000 L8 334,000 3.5 De·li l Canyon 100 8,600 0.8 16,800 1.5 .(w1th Watana 70 6,100 0.6 12v100 1.1 100%) Dev1l Canyon 100 79,000 7.2 155,000 14.2 (.with Watana 70 55,000 5.0 109,000 10.0 70%) TABLE 7.15: LENGTH-DISTANCE CRITERIA FOR IDENTitiCATION OF FAULTS AND LINEAMENTS FOR PRELIMINARY FIELD RECONNAISSANCE D1stance from dams1te Minlmum Length of Alignment Fault of L1neament (km) (m1les) (km) (miles) 0 to 10 (0 to 6) 5 (3) 10 to 50 (6 to 31) 10 (6) 50 to 150 (31 to 93) 50 (31) . ~,· -:~· ,, ·---····~·~··, .. ·.~.,, .. ~· ,. '-··'·><•-·····--·~_, .• , <'- I I TABLE 7.16: SUM.t~ OF BOUNDARY FAULTS AND SIGNifiCANT FEATURES fault (r) DJ.stance (km) from I I Feature or Linea-Length Oev1.l No. Feature Name ment (L) (km) Can~ on Watana , BOUNDARY FAULTS I ADS-1 Castle Mountain Fault r 200 500 115 Benioff Zone r .60 so HB4-1 Denali Fault F 2000 70 64 I WATANA SIGNIFICANT FEATURES I KC4-1 Talkeetna Thrust r 354 25 6.5 KD3-3 Susitna r eature F 153 25 3.2 0 I KD3-7 L 50 35 0.0 KD4-27 Fins Feature r 3.2 37 o.o I DEVIL CANYON SIGNIFICANT FEATURES KCS-5 L 20 7 31 I 1<05-2 F 5 5.6 38 KD5-3 L 82 5.8 23 I KDS-9 L 5 1.6 39 KD5-12 L 24 2.4 28 KDS-42 L 5 0.8 35 KDS-43 L 2.4 o.o 38 I KDS-44 L 34 0 .. 5 37 KDS-45 L 31 "' 1.3 41 I I I I I I 1 I I ,. I I I ~: I I I I I I I I I I I I I TABLE 7.17: SUMMARY Of tARTHUUAKE SOURCES CONSIDERED IN GROUND MOTION STUDIES Earthquake Source Benioff Zone.: -Inte&:"plate 8-1/2 -Intraplate 7-1/2 Denal.l Fault 8 Castle Mountain Fault 7-1/2 Talkeetna Terra~n 6 Closest D1stance to Dam Sl.tes (km) Watana Q_ev~l Canyon 63 90 48 58 70 64 105 115 WJ.th~n a few km of e~ther sHe I TABLE 7.18: WATER APPROPRIATIONS WITHIN THE: SUSITNA TOWNSHIP GRID I -,----------+-"'~'~' s_"'uJ:H'"'"f•·Tl'n" ACJ:E...,'fi~Att..:""".H~A-:no~ll"'o:'P\''t''l'ni1U~t'.~lli!:.A.,..,ll,.,.l uiTrN:s...-+--~uoo:'li'A,"''M Yr~---+--...,.u'""""t<uu~Nt.;. ""wA'li"'!II"P"'t~KA~~.t''N't'tm'l'!?wi'""'R~ J.Afl......:.:ui"'TT''"'Ns+-"'""u~A, Y!:i~ I TYPE cfs gpd ac-t:t/yr OF USE cfs gpd ac-ft/yr OF USE Cert:tf:tcates s~ngle-farnJ.ly d\'lelhng 2 to 4 un1t houslng Grade Schools Fire protection An~mals Lawn and garden ~rr~gat~on General Crops Total Perm.1ts S.1ngle-family d\'lelling Vegetables Total Pending ~ S1ngle-family dwell~ng Lawn and garden irr1gat1on Placer gold Total TOTAL 0.1 . o.; 0.1 4,500 75 63.5 200 100 4,938.5 250 75 50 125 5,313.5 12.5 12.5 1 1 13.5 365 214 365 184 153 153 365 153 365 183 184 5,440 1,200 910 500 94 8' 1l\4 1,000 250 1,250 9,.394 0.5 5.5 6.0 -· 6.0 .365 365 334 365 365 60 91 365 214 I .,. ' - I I I I I I. I I I I I I :1: .. •.· I I I I I •• I I I I I ••• I I I I TABLE 7.19: SUMMARY OF WATER APPROPRIATION* TOWNSHIP GRID r Susitna .153 50.0 .0498 16.3 F.ish Creek .000116 .021 .003 2.24 Willow .Creek 18.3 5,660 .153 "128 little Willa\'>/ Creek .00613 1.42 .00190 1.37 Montana Creek .0196 7.85 .366 264 Chulina .00322 .797 .000831 .601 Susitna Reservoir .00465 3.36 Chulitna .00329 2.38 Kroto-Trapper Creek .0564 10.7 Kahiltna 125 37,000 Yentna .00155 .565 Skwentna .00551 1.90 .000775 5.60 * Figures from Table 7. '18 all converted to cfs and ac-ft/yr equivalents as follo~s: 1 gpd = • 00000155 cfs 1 cfs = 1.98 ac-ft/day ' TABLE 7.20: WATER APPROPRIATIONS WITHIN ONE MILE OF THE SUSITNA R1VER -I ADDITHlNAL SOURCE. LOCATION* NUMBER .TYPE (DEPTH) AMOUNT CERTIFICATE T'19N RSW 45156 S~ngl~-fam1ly dwell~119 well {?) 650 gpd general crops same source 0. S ac-ft/yr T25N R5W 43981 S1ngle-family dwelh·ng well (90 ft) 500 gpd T26N R5W 78895 'S1ngle-family dwell~ng \'I ell (20 ft) 500 gpd 200540 Grade school well (27 ft) 910 gpd 209233 Fire stabon well (34 ft) 500 gpd T27N R5W 200180 Single-family dwelling unnamed stream 200 gpd lawn & garden ~rr~gat~on same source 100 gpd 200515 S.1ngle-family dwelhng unnamed lake 500 gpd 206633 Single-farn1ly dwelling unnamed lake 75 gpd 206930 Single-family dwelling unnamed lake 250 gpd 206931 Single-family dwelling unnamed lake 250 gpd PERMIT 206929 General crops unnamed creek 1 ac-ft/yr T30N R3W 206735 Single-family dwelling unnamed stream 250 gpd PENDING 209866 S1ngle•family dwell~ng Sherman Creek 75 gpd lawn & garden ~rr~gat1on same source 50 gpd *All locat1ons are w1thin the Seward Meri.dian. DAYS OF USE 365 91 365 365 334 365 365 153 365 365 365 365 153 365 365 183 I I I I I I I I I I I I I I I I I ' ' I I I .I ., I •~ "" I I I I ' I I I I I. I I TABLE 7.21: HECTARES AND PERCENTAGE OF faTAL AREA COVERED BY VEGETATION/HABITAT TYPES ON 1:250t000 SCALE MAP Percent of Hectares Total Area Total Vegetation 1,387~607 85.08 Forest 348,232 21.35 Conifer 307,586 18.86 Woodland spruce 188,391 11.55 Open spruce 118,873 7.29 Closed spruce 323 0.02 Deciduous 1,290 0.08 Open birch 968 0.06 Closed birch 323 0.02 Mixed 39,355 2.41 Open 23,387 1.43 Closed 15,968 0.98 Tundra 394,685 24.20 Wet sedge-grass 4,839 0.30 (Mes~c) sedge-grass 184,358 11.30 Herbaceous alpine _ 807 0.05 Mat and cush~on 65,001 3.99 Mat and cushion/sedge-grass 139,680 8.56 Shrubland 644,690 39.53 Tall shrub 129,035 7.91 Low· shrub 515,655 31.62 Such :53,549 2.06 Willow 10,645 0.6.5 Mixed 471 ,461 28.91 Unvegetated 243,392 14.92 Water 39,840 2.44 Lakes 2.5,162 1.54 Rivers 14,678 0.90 Rock 113,712 6.97 Snow and ice 89,841 5.51 Total Area 1,630,999 100.00 • 0 --~ . . () TABLE 7.22: HECTARES Of DiffERENT VEGETI\TION TYPES TO BE IMPACTED COHPARED WITH TOTAL HECTARES Of THOSE TYPES IN THE ENTIRE UPPER SUSITNA RIVER BASIN (Number in parentheses is the percent of the vegetation types as found 10 the entue Upper Basin) lmpounaments B o r r o w i\I"eas Devil Can~on Watana A c D I;" H • Woodland spruce 162 (0.09) 4766 (2.53) 228 (0.12) 77 (0.0/~) 15 (0.01) 227 (0.12) Open spruce 862 (0. 73) 3854 ( 3.24) 48 (0.04) 7 (0.01) ·125 (0.11) Open b.1:cch 73 (1.54) 318 (32.85) Closed birch 470(a) 491 (a) 1 (a) Open conifer-deciduous 300 ( t .28) 1329 (5.68) 19 (0.08) 9 (0.04) 94 (0.40) Closed conifer-deciduous 758 (4.75) 869 (5.44) 2 (0.01) Open balsam popular 7(b) Closed balsam popular 10(b) 2(b) Wet sedge-grass 12 (0.25) 100 (2.07) 6 (0.12) 1 (0.02) Mat and cushion tundra 78 (0.12) Tall shrub 19 (0.01) 580 (0.45) 18 (0~01) 23 (0.02) 8 (0.01) Birch shrub 58 (0.17) 474 (1.41) 18 (0.0.5) 92 (0.27) 73 (0.22) ~Jill ow 16 (0.15) 55 (Oo.52) 7 (0.07) -LnwmJ.xed shrub 6 (+) 785 (0.15) 101 (0.02) 1'13 (0.02) 109 (0.02) 55 (0.01) 46 (0.01) lakes 1 (+) 47 (0.22) 3 (0.01) 1 (+) Rivers 835 (5.69) 2106 (14.35) ·w (0~07) 6 (0.04) Rock 14 (0.01) 63 (0.06) 1 (+) Total Areas 3603 (0.22) 15839 (0.97) 500 (0.03) 322 (0.03) 228 (0 .. 01) 71 (+) 499 (0.03) Upper Su~1tna River Blbs.1n 188 1~~~1'1 1lff,IS73 ~a 3).23 231,3m7 15,9.1SS 4.,_,t8~~ ( 6.5~&10, c) 129"m3s :n,~ 10,.~'5 47l,.4n>1 2l,.m.i2 14,.~/.8 11J~:mJ2. 1, 211 ,.SRJ!i.. (a) Hectares of closed b.:trch are apparently greater 1n the impact area9. than in the entue basJ.n because the bas1n was mapped at ·SJ· much smaller scale, and many of the closed birch stands d1d not appear at that scale. (b) Balsam poplar stands wel.'e too small .to be mapped at the scale on .wluch the Upper Sus.1tna R1ver Bas1n was mapped. (c) Total hectares of mat and cushion tundl.'a are much greater than this, but many hectares were mapped as a complex with sedge-gl'~~ tundra. --:Ill (--;-•• ,. !-~-•• -•• --~--. . ,, ..• ,.· .... \.~~ ' : I I I I ... I I • I I I I I ·I cOOK INLet 0679 19 . PALMER .~0688 · DATA COLLECTION STATIONS STATION RAPIOS G 007~ oosz • {A) SUSITNA RIVER NEAR DENALI X (Bl susmllA RIVER AT VEE CANYON X (C) SUSITNA RIVER NEAR WATAI';.":. DA'MSITE X X (Dl susmu. RIVER NEAR DEvlL CANYON • .X (E) SIJSITNA RIVER AT GOLD CREEK X (F) CHUIJTJIIA RIVER NEAR TAU<E£TNA X (G) TALKEETNA RIVI;fl NEAR TALKEETNA X (Hl SUSJTPU' RM:R NEAR · SUNSHINE · X {I) SKWENTNA ~IVER NEAR SKWENTNA. X (J) YENTNA RIVER NEAR: susrrNA stATION X (t() SUSITNA RIVER AT SUSITMA STATION X )( X X X )( X X x2 X X X X X X X X XIX .X X X X X X X )( X X t:) & 0~ luo 0::~ a;:r t:)~ !!?"' 154. a.:o X )( X 1957-PRESENT p96t -1972 a 1980-PRESENT X X X X 1980 ... P~ESENT X X X 19 .. 9.-PRESENT X p9ss -1972 a l~$0-P~ESENT X 1~64.;_PRESENJ X 1~1• PRESErff X' t!l59.,..J9BO ~0-PRESENT ~14-PRESENT I DATA COLLECTED • t'TMAMnDW-camNuoui ftfCOftD a trrREA.MF:I.OW ~ fMTIAt. N!CORD ~l WAT£fl QUJ.UTY ' T WATER TEMPERATURE w stDIMENT DlSCJURGE a CUMATE -FREEZING R41N A. .. D IHCl.DUD fCING • SNOW C:OURSE A SHOW CREEP NOTES tlttn. ...... ~ OIOo •02(l0 0500 0400 oeoo QEiiX) 0100 ()8()!). osoo. I. PARAMETERS MEASURED LISTED IN J\PPENOlX' :Sl Z. CONTINUOUS WATER QUALITY MONI~ tNSTALlED 3. DATA COLLECTION 1981 SEASON. 4, THE LETTER BEFORE EACH STATI.ON ~ME \N "THE TABLE IS USED ON THE MAP TO i1ARK 'mE APFROXIMATE .lOCATION Of THE STAnoNS. 0 10 20 MILES SCALE (A~ ... ) FIGURE 7.1 I I I I I ' I I I I ' I I I I I I I I ~--------------------~~---~--------·----------------------------------~ G CHULITNA RIVER YENTNA RIVER :·:·: SUSITNA RIVER DEVIL WATANA CANYON SITE SITE 20o/o GOLD CREEK COOK INLET TALKEETNA RIVER =~== _or~·:;:=·=·=· ·;·l1~IIIIII¥I@ PARI<S HIGHWAY BRIDGE GAGING STATION SUSITNA GAGING STATION AVERAGE ANNUAL FLOW DISTRIBUTION WfTHIN THE SUSITNA RIVER BASIN FIGURE 7.2 .!111m I .,, ... -..• , ·' " ' . : ----' 50,000 LEGEND -WETTEST YEAR-1962 0 40,000 2 0 0 AVERAGE YEAR w (/) 0::: w a.. DRIEST YEAR -1969 .... 30,000 w w LL (.) m ·::l 0 - ·3: 20,000 "' 0 _J LL ~ <( w a: .... U) 10,000 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC MONTHLY AVERAGE FLOWS IN THE SUSITNA RIVER AT GOLD CREEK FIGURE 7.3 I J f I I I I I I "" I ' I ' I I :I "" ' I I N 0 -)( -en LL. 0 - 1.1.1 (!) a:: c:( :I: 0 en i5 560.00 '400.00 240.00 o.ooL----r---,---.,...-~:::=:=:::::::=::::::= 0.00 0.20 0.40 0.60 PROB OF EXCEEOENCE FLOW DURATION CURVE MEAN MONTHLY INFLOW AT WATANA PRE I POST PROJECT ~ 0.80 1.00 FiGURE 7.4 .. >, . • "' . "' ' '". '. ·~· ''"-" • ·"'"' ,. > '"-'"""" I J '" ' I I ' I t ' I .,_ I I '-, .~· I ·t I ' ,. ' .,:. I Clb - liC -(f) LL 0 - l&J (!) 0::: <t :t: 0 (f) 5 560.00 0.00-+----.,....-----.----.--"'"-1---...-----...,.--..---; 0.00 0.20 0.40 0.60 PROB OF EXCEEDENCE FLOW DURATION CURVE MEAN MONTHLY INFLOW AT DEVIL CANYON PRE-PROJECT 0.80 1.00 FIGURE 7.5 . • If) 0 )( -(/) LL. 0 -~ 0 ...J IJ.. (!) > <t RETURN PERIOD IN YEARS 1.25 2. 5 10 100 IOQQ) lO,OOO 20 .--------,.--.---,---.--,-·--,,--.·-'-r-----oc----.r----.---.---.----,.-----.-------r--..----..--~· ···--1.11 ( ·---· ·-.... ·---.. ·~·--------·-··~---···----.. ·-·· ---t-- 10 9 8 7 1---·-·-· ~-.-. -.. -...... 6 5 ~--~ ---· ··------· ·····---·-··--!--·-~~-~--'~~-·· ·-r-·-----~----~---~-~~---J----+--·· -~---7 MIN. ANNUAL FLOW R.EJ~il:>.RDED 4 ~------·-----·--·· .. ---·· "---·-· ·---1---+-----t---t--·1-------~-----· ··--~·-·· ·-· ----·----.. ··-----! 3 I 0.01 0.1 0,2 0.5 2. 5 10 20 30 40 so so 10 eo 90 95 98 99 99.8 9~Ml 99.99 PERCENT PROBABILITY OF EXCEEDENCE ANNUAL FLOW DURATION FREQUENCY CURVES SUSITNA RIVER AT GOLD CREEK @ INDICATES CURVE FOR 2-YR. AVERAGE FLOWS FIGURE 7.6 I ' I I; I t a ' I I I ' a ' I I t t I 90 80 70 60 ;;so 0 -)( U) lL 0 -3: 0 ...J lL 40 20 / 10 0 0 ~ 5 "' ·;\ I \ I ~ ~ -........ ~- 10 15 20 TIME (DAYS) I: 50 YEAR FLOOD INFLOW HYDROGRAPH SUSITNA RIVER AT WATANA DAM SITE 25 .. ·.; 30 FIGURE 7. 7~~~~~ 1 I I ' I I ' I ' t t I I I t ' I I I I 180 160 140 120 ;;"100 2 X (I) u.. (.) -;;= g u.. so GO 40 20 0 l / I v 0 5 . l I @ \ \ ~ \ ~ I ·~ i . I \_ -· -/ I , i • I r l u ' i 10 15 20 25 30 TIME (DAYS) I: 10000 YEAR FLOOD INFLOW HYDROGRAPH SUSJTNA RIVER AT WATANA DAM SITE FIGUR~ 7.81 ulm I I ' I I ,I ' I. ' I I I I I I I I I ' I 360 320 280 240 ;;'200 Q X ff (.) -3: 0 ..J u.. 160 120 80 40 0 0 A \ 0 ~ ) ~ I < \ I \ . \ I '\ J . J / - 5 10 15 20 25 30 TIME (DAYS) PROBABLE MAXIMUM FLOOD INFLOW HYDROGRAPH ••. sustrNA RIVER AT wATANA DAM s1TE l'om FIGURE 7. 9 .· ,bftlll . -~-----~ --------------~ -----.. -------·-- .., 0 - 60 50 40 30 20 UlfO ~ 9 -~ 8 0 7 ..J l.L 6 . 5 4 3 2 1.5 - I r . ,.....r. .,..-t /,. I-- l SUSITNA RIVER AT GOLD CREEK // '.,.,. r':! , ,. .Jill'!"'_ ~,....... . \ '/ ~ -""' .,.-[i v v 'r',.. ; ~ ........ .. [\ISUSITNA RIVER AT CANJmwELL ~ v ~ ~ ~ / ' ~ ~J ...... It ~ v ~ ~ v SUSITNA RIVER AT OENALJ; .L_ v !--""' / v ...,..,.. v ./ """"' ~ ,. .. _,/ v v _,. I"" """ ~ _/' ...-.<""' ~ .... -·· -. ..L ~ _/ -· ~ ......... \' ~ ~ ,..., ' ~,...__. _,..,; 1---~MACLAREN RtVER AT PAXON v I-" ~ v L v v --v ~ ~ ,.....,... ~ . """"'-' ~ ~ 2 3 4 5 6 7 8 9 10 20 30 40 50 60 70 80 90 100 120 13Q 140 SUSPENDED SEDIMENT DISCHARGE (TONS/DAY) x 103 SUSPENDED SEDIMENT TRANSPORT SUSITNA RIVER AT SELECTED STATIONS FIGURE 7.10 :a I I T33N I T 31N I I I I I I I •• I I I I T 32 N T 31 N R2E ·o a: ~~~~~~~~~~~~~~~~FrK7,~~~~~~~7\.~~~~~--~--~~~~~ Modified from· Csej1ey,et ol; 1978 w (I) CENOZOIC QUATERNARY r---, I t .._ ___ ... TERTiARY (¥'--r-:w:, I + + "' 1.1. -4.-............. ·~·.· MESOZOIC CRE'IACEOUS E::...:::::::-::-J ... _-..;-_-:-_--:_-..;~ r...-;;..-_-: ... :·:.... -:1 JURASSIC [l]l[Q • <l • • LEGEND UNDIFFERENTIATED SURFICIAL DEPOSITS UNDIFFERENTIATED VOLCANICS 8 SHALLOW INTRUSIVES GRANODIORITE, BIOTITE-HORNBLENDE GRANODIORITE, BIOTITE GRANODIORITE SCHIST, MIGMATITE, GRANITIC ROCKS UNDIVIDED GRANITIC ROCKS MAFIC INTRUSIVES ARGILLITE AND LITHIC GRAYWACKE TA'l\ i\1\/';J ~AA6.d TRIASSIC ~Z"i'...,. <N I \" .J. > " .> ,.1 ____ __. PALEOZOIC AMPHIBOUTES, GREENSCHIST, FQ~T£0 DIORITE BASALTIC METAVOLCANIC ROCKS, METABASALT AND SLATE BASALTIC TO ANOESITIC METAVOL~lCS LOCALLY J NTERBEDDED WITH MARBLE THRUST FAULT TEETH ON UPTHROWN SIDE,DASHEDWHERE JNFe;lHEJDI ---.y•---, • • • OOTTED WHERE CONCEALED INTENSE SHEARING POSSIBLE THRUST FAULT, TEETH 00 UPTHROWN • • • v• • • • '\1 • • • SIDE \1 PROPOSED DAM SITES GRANODIORITE, QUARTZ DIORITE, TRONOHJEMlfE SCALE IN MILES REG·IONAL GEOLGGY FIGURE7.11 bal l l .~~~-~---~------~-~---~~----------------_,---.~---~~---~..-- ------------------- @ '60° 150° \ \ \ \ \ '\~ ' EURASIA-N ',, PlATE . .. \ \ \ \ WOODWARD -CLYDE CONSULTANTS 14656 A DECEMBER 1980 180° NORTH ' -. PACIFIC 180° 160° AMERICAN PLATE PLATE . LEG.END ~ Relative Pacific Plate Motion -----Plate Boundary~ dashed where inferreu 6 1\ 0 -Shelf Edge Structure with Oblique Slip -----Intraplate Transform or .Strjke-SUp Fault 150 PLATE TECTONIC MAP n 'l ' '600 FIGURE 7.12. I I I I I I I I I I I I I I I I I . 1/ l LEGEND _....::., u -"""~~-·D -- ._,., __ _.._ ....,,., . VVv'V 150° A'\ I ,? Mapped strike-slip fault with dip slip component Mapped strike.sl iP> fault, arrows show sense of displ:acement Mapped fault, sense of displacement not defined Inferred strike-slip 'fault Mapped thrust fault, teeth indicate uptbrown .side of block. dashed where inferred Mapped thrust fault. teeth indicate inferred upthrown side of blc~k WOODWARD-CLYDE CONSULTAN1'S ~4658A DECEMBER. f980 RANGE NOTES (j) C2> <3> @ (,5) ® CD ® <9> 10. 11 . 12. c 0.9. 2.0 cm/yr Hickman an~d ~mpbell, (1973); and Page, (1972). 0.5 .. 0.6 cm/yr ~+-: •. n. and others, (1973}. 3.5 cm/yr Richter and Matson, ( 1971}. 1.1 cm/yr, no Holocene activity farther east, Richter and Matson, {1971). 0.9 -3.3 cm/yr Richter and Matson, (1971) Inferred connection with Dalton fault; Plafker and others, (1978). Inferred connection with Fairweather fauh; Lahr and Plafker, (1980), Connection inferred for this report. 0.1 -1.1 cm/yr Detterman and others (1974); Bruhn,(197S 1• Slip rates cited in notes (I) through ® are Holocene slip rates. All fault ~ocations and sense of movement obtained from Beikman, (1978}. Figure 7.14 presents Section A-A'. ' ' 0 20 40 MILES SCALE TALKEETNA TERRAIN MODEL FIGURE 7 .. 13 •• -..,------------------~---- - - 1 964 Earthquake Rupture· Zone NOTES '--- 1. location of Section A-A' is shown in Figure 5·1. WOODWARD • CLYOE CONSULTANTS 14656 A OECEMBt:R 19SO ------ ------ Beni0:mf Lone Seis.mil:'iw 1 - Zone of Low Historic Seismicity Plate Motion Relative to North American Plate SCHEMATIC TALKEETNA TER.RAIN SECTION SCALE OL...------40~----~80 MILES FIGURE 7.l4 I ·~ ---------~-------- ANNOTATE OVERLAY a FILE -NO NO PLOT ON BASE MAP. ASSIGN MAP CODE NUMBER. RECORD NUMBER ON MAP. FAULT 8 LlNEAMENT SUMMARY SHEET a REMOTE SENSING LINEAMENT WORKSHEET INTERPRETATION OF REMOTELY SENSED DATA DOES LINEAMENT MEET SCREENING CRITERIA? .f YES ASSIGN REMOTE SENSING CODE NUMBER. DOCUMENT a COMPLETE REMOTE SENSING LINEAMENT WORKSHEET IS FEATURE PLOTTED ON BASE MAP? ~'YES ASSIGN EXISTING MAP CODE NUMBER. RECORD NUMBER ON FAULT 8 LINEAMENT SUMMARY SHEET 8 REMOTE SENSING LINEAMENT WORKSHEET J . . LITERATURE .REVIEW RECORD REFERENCE ON REFERENCE DOCUMENTATION SHEET I PLOT FAULT ON BASE MAP. ASSIGN MAP CODE NUMBER. RECORD NUMee:R ON MAP S ON FAULT a LINEAMENT SUMMARY SHEET DOES FAULT MEET SCREENING CRITERIA? NO ~ YES 1r COMPLETE DOCUMENTATION ON FAULT a LINEAMENT SUMMARY SHEET. RECORD ON FAULT a UNEAMENT -INDEX SHEET -'------,..-------~ I FIELD STUDY I t FIELD OBSERVATIONS RECORDED ON FIELD DOCUMENTATJON SHEET. PHOTO LOG 8 FAULT a LINEAMENt PHOTO LOG. -D.Q~ENT a If-~£ FLOW DIAGRAM OF DOCUMENTATION PROCEDURES FIGURE 7.15 WooDWARD-'CL'iDE ~QNSUJ,.TAMTS J46ts8A DECEMBER (980. I I I I I I I I I II I I I I I tk\;N "'. -'"; _.._,I t I .. . l ,., " . .. ... / :'> i ' ~a ... ,,., ... CONSULTANTS 14f;i58 A DECEMBER 1980 ·. ': ~ .. ~i;~ .., ....... ~ ... -· ' ~ ~ ~ :. ,;-~ . '< "' ...... l . '~ -~~\ "'"',: ..... ·~ •'i :.~ . \ #·1<-~t,'\.. ., .... ....--J-- ... ... . '*·,;·t·· LEG,END BOUNDARY FAULTS Faults with recent disploi:ement 0 20 40 MILES SCALE BOUNDARY FAULT AND SIGNIFICANT . FEATURE MAP FOR THE SITE REGION FIGURE 7,J6 [iiJ• I I I I I I I \....... -~._ "'..;~: •.. '"" __ ..,_,.,.~:-r--., I ~~-~' I I I I I I I I .. ..,._-,...~'--~·········-.,...._, \ L . , .. ' «----~J--1 • ' ' -·-+-.,~ .... ~ _ .. , r- . ,J-., .. :\:1 -"" ' _,-.~-.... ~-. . .. =·-a.-E ........ .. .,.~ ~f63°&r- 0 2 MILES SCALE WATANA SITE SIGNIFICANT FEATURE MAP - - - -·-- - - - - - - - -... ·--' --· 0 4 8 MILES SCALE ~~ ~~~~iiiiiiiiiiliilaBiiiiiiiiiPJiiiJ ..,. -.~. DEVIL CANYON AREA SIGNIFICANT FEATURE MAP . ' WOODWARD-CLYDE CONSULTARY~~-A DECEMBER t98o FIGURE 7.18 I I I I 1: I I I I I I I I I I . :I I I I r---------------------------------------------------~---~~------------~----~ WOOOVIARO -CLYDE CONSULTANTS. 14658 A DECEMBER i$80 0 SCALE DEVIL CANYON SITE SIGNIFICANT FEATURE MAP Fl GURE 7. 19. fiil .·1 I I I I ,I I I I I I I I I rl I I I I -148-.0D ... -·--_L_.........-.... ,.,.,..,...,-• . . ......-~ . .........,..---._,_.._. ~-. ._.. ... .._. .. uB!'r'\ ---·--·-' • fau\t P ~:...---· oena\~.--. __.,..... .. __...---e CANTWELL .,.,-· --151-.00 +.--.150c'OO + ---149.00 + ~ / _ _..,.,.,.. /-. ..-- r~-~---~----;---·--------------_.-.---~----------:--o---............_.---·--~~ t,.....o• ~ 0 / . --~~--...-, . . /. . I .--·--· c o/. I /'. I "... ~-..... ·. I ./· 1 ."" ·(9 · ~v ot:NAU • 1 /./ I • o . «'j/'. I I ~ t> C:J~~ ~1 I t5J / o .· .~ I ., II Mt. McKinley LEGEND REPBRTEO MAGNITUDE 0. 4.0 s.o 2·0 1 . 0 0 C) • / I 0 0 KD5-3 DEDJ"" / t-1·--/-Microearthquake ~ e / Study A~rea + j + + .-/". · o · ./ -h.· I +s3 .no I 0 • HUR ~ C) ~ / 0 / I + 1 Sl .oo 0 ./· o 6 DCR J5 / I . e " fi / I 1 ~ / = o .. ~-. . / I I KDS-43 h-"/ KDS-2 (I} • SBL (9 (!)· . • KD4-27 / I 'S"c: '/ DEV .Aofi-12 C) -~WAC ~../ JAY . I I /.~ ~~,/( • KDS-42 / ..... : ... , ••••• t["'•... • . I \(05-46 . • ·-r·~ . ·~ . WAT / • ····~ •• KD3·7 . I _..--·-;-_/ o~. "'· \KC5-5 /'\ , ••• ···~.. I { / KD5-6 /-• · /-t-(}<" • • • o ' / (1} • /. \ \ • / 4~. ~'~ I I / .. CNL I) \ \ ./· ~~~'" '[ I I /. 0 C) KD544 . . / 4.ee'lfl?> e I ' /• C) o e ./·~:.:~ I J 6 0 / ;· ~GAB Cluster No. 1 I 1 (!) DPC / /' UPG I f .. / I / j/ 0 .ttl~ Clustec No. 2 • ~ .o.KOS I I " / / • 0 TKR.t. 0 c e • o • ~ I // / • : I I / 0 C) ;· I I e ;ALKEerny/ ~ .y .· • I ------L-_._<!!__·--------------,----'!9...._-_o_. ____ . __ _j --{9. --1so .. -oo .(!) C) 0 (!J (I} 0 + -149.00 0 + -148.00 WOODWARD • CLYDE C.ONSULTANTS 14658 A DECEMBER l980 6 GRB Station location and name used for this .study c-C" Projection for cross-section is shown in Figo...tre 7:.19 NOTES 1. Magnitude symbol sizes .are shown on a continuous nonlinear scale. _, 2. Local events are those inside the dashed lines. Events outside the dashed l.ines are con•idered to be less well-f6cated. 0 10 20 MILES SCALE SHALLOW (FOCAL DEPTH < 30 km) LOCAL EARTHQUAKES. LOCATED FROM 28 JUNE THROUGH 28 SEPTEMBER 1980 . +s2.oo -147.00 FIGURE !.20 .ill I ·ll I I ·I I I 10 I I I I I I ,, •• I I. -lbl .. uo l ~T · • Mt. McKinley + + ... -151.00 I. . - -150"00 + .•.. -149 .oo -}- •CANTWELL -148.00 + r --------------. .. . . . . . . . ----· --.-----·.-----··---------~ I . I I 1 c I I 1 CJ DENALI •1 I I I 0 I I ~ o I . .,..14 7. 0'0 +ss.so LEGEND - REPBRTEO MAGNITUDE .. C) 4.0 (!) 3.0 (!) .2 .o e 1 .o f A DED t-t---Microearthquake J + + (!) + \ · Study Area +as .oo I I • (') A ;R "' " ';. OCR (') " e ~~ ~ i!) J (9 ° 4 :BL C) e l I (!) (!) (!) i!) D C)(!) l I • DEV (!) 64 vfA~<!> .6 JAY ,. WAT . . ciD I ~ l I <!>• (!J I I (')(!) 0 I (!) (!) i J 6 CNL (!) (!) t r (!) i!) C'.l ~ (!) t I m l <!> ~ tGRB ' i!) (!) (!) (!) A (!) C) I f. (!.) UPG .I .o~ ~ . I (!)C) (!) 0 .KOS ' J {!] .(!) l I I m (!) I .(!) I ~ 0 ~ (!) (!) •· A -s> i!) f •TALKEETNA V · 0 • ---------·----Lil_-. (!) • o-----;----------------------==- + -150.00 + -14B.nn .a + -148 .c:o 0 i I I I _____ L C) C' •, A GRB Station location and name used for this study C-. C' Projection for cross·section is shown in Figure 7.19 NOTES 1. Magnitude symbol sizes are shown oo a continu~. nonlinear scale. 2. Local events are those inside the dashed lines. Events outside the dashed lines are-considered to be less well-located. 0 10 20 MtLES SCALE ~~- DEEP (FOCAL DEPTH > 30 km) LOCAL EARTHQUAKES LOCATED FROM 28 JUNE THROUGH 28 SEPTE~~BE.R 1980 +s2.oo -147.00 FIGURE 7.21 · .• ~.··.· .... ·····.·.·.··· .. ·.-... ··.··.·.·.· • I > ..... . .. WOODWARD .. CLYDE CONSIJl.TANlS :f465$.A DECEMBER J980 ~ ;;,.;_;_i>, .. , ~' <t,· ~-...-·; ., • '-~-·~ .... ...:.,,. ''"""" .;: ·--... ;,.,~, :. ' ....... ,: •••. :_ . ~ .... :. -~ -·" -'''"·~-· ' '-~· -. I I I I I I I I I I I I I I. I I I I I c 0 0 0 .r::. b. 50 Q) 0 ' ~ 0 0 1ool WOODWARD • ClYDE: COI'iSULTANTS J~658 A DECEMBER 19.90 Approximat~ Upper Ed!1e oi Benioff Zone ~ (f)O·~ 0 0 0 "··· •"'"-~·-'--'----'-----~ ,;_, 0 0 View Direction i!~ NE 0 0 SE 0 0 i ' LEGEND Hypocenter and Magnitude (ML) c \ 3.0 ; 0 2.0 0 1~0 D~V Devil Canyon Site and Microearthq!.:l.ake .-Station location WAT Watanr. Site and Microeartl1quake A Station location NOTES l. See Figures 7.20 and 7.21 for location of cross section. 2. All earthquakes shown in Figures Z20 and 7.21 and the DEV and WAT sites .:are projected to the plane of this cross-section.. 20MILES SCALE CROSS-SECTION OF CRUSTAL AND BENIOFF ZONE MICROEARTHQUAKES LOCATED WITHIN THE NETWORK FaGURE 7.2.2 fill l I I I I I I I I I I I I I I I • 240 220 200 180 160 e 14o - . . §131 Watana • y Combined lif1· . ~D~~il Cahydn ... • J!l 54·· !@56 .. • • • • : 39 @]60 • ... . . . ·S· -. . . ' . . . . . . . . .. ... . 120 . . {@130 • • . "'5 t@Jr ~ J2· .. : . 9" ., " • Rill o. • • •• OtQ. o • I •: H.:J · 23 •• _.., • • • : • : ~· · · . ~ 81 soj~1s.35 100 32 •• t?l-. . . . . : 18 l~j29 . . .. -• .. • l!J !.!:::::1 ... bcs. ,@, .. • ' 5 ~ = •ra36 ; .... ~-~;~~ 1>... ~ 60 40 10 .s :rEi137 lliiill ~24 .c:.55 Approximately 11,000 reservoirs without rer4vtecl RIS not plotted ~59 100 • • • • • • . . 10,000 ~1 . 'I 100,000 Reservoir Capacity in 106m3 (1ogarithmic scale) _.,.~···· 500,000 ..~·~ \ NQU: ThtyfolfowJng nwrvoil'l liYIIf~ no~ plo~ed ~use of .. .. i~ufflc:i~nt 'data: Kintrit\1)1, Sharav&thl. ~ . I ! : LEGEND 0-aep ancVor very large re~rvoir Accepted case of R IS~ maximum magnitude-~ S A~pted case of RIS, maximum magnitude 3-5 Ael:epted ca$e of RIS: maximum magnitude S 3 Ouest5onabte :case cf rH$ Not RIS ·~1 .. ~u,..k (USSR) .depth is.jft excus of ~~ m. . ~ / ; .~ti' ,/ ~-~ PLOT OF WA*l"ER DEPTH AND VOlU~JtE FOR WORLDV'JHJE RESERVOiRS AND REPORTED CASES OF R!S '"'--'··--·~:-:'!:-~~-~-:-~· .~ .. ·-~"' ~· -· -------..-=----F-IG~~..!L.3 ___ .•. ~.·;~~~:.••~ .. -wooowA.~o • CL;YOE t;ONSULTANT~ (~§.~~ ~)-4EC!EMGE8 l9.80 ..:!j -"'----~' ~~-.. ' ... ' ·, . I I I I I I I I I I I I I I I I I I I 0.25 en -cc ........ 0 0.20 ~ (,) c: ·cp ... ::s u (,) 0 -0.15 0 > .!: :.0 t!:J .Q 0 ... a.. 0.10 0.05 2 3 LEGEND 4 I 5 Magnitude of largest R IS Event 6 7 Deep, very deep~ and/or very large reservoirs with sedimentary geology -------Deep, very deep, a!ld/or very large reservoirs with igneous geology Deep, very deep, and/or very large reservoirs with metamorphic geology PLOT OF VARIATION OF RIS PROBABILITY WITH DIFFERENT GEOLOGIC SETTINGS FOR DEEP, VERY DEEP .. AND/OR VERY LARGE RESERVOIRS FrGURE 7.24 WOODWARO-ClYtiE CONSUt.TA~TS 14~58 A DECEMBER 198() I I I I I •.. I I I I I I I I I I I I I I - en -a: ..._ 0 Q) (,) c: Q) .... ;::, 8 0 -0 > .~ :c <1:1 .Q 0 .... 0.. 0.25 0.20 0.15 0.10 0.05 2 3 LEGEND > 4 5 6 Magnitude of Largest RIS Even1t Deep, very deep, and/or very large reservoirs in thrust (compressive) stress regime · Deep, very deep, and/or very large reserYoirs in normal {extensional) stress regime -----De~p, very deep, and/or very large reservoirs in strike--s! ip (shear) stress regime PLOT OF VARIA1'10N OF RIS PROBABILITY WITH DIFFERENT STRESS REGIMES FOR DEEP, VERY DEEP, ANO/OR VERY LARGE RESERVOIRS 7 Ff G URE 7. 25 WOOOWARO-CLYDE CONSULTANTS 14658 A DECEMBER 1980 [iJ I I I I I I I I I I I I I I I I I I LEGEND l~ Vertical-component, short-period,tdemetered station L~· Three-component, short-period, tefemetereq station A Thr;ee-component, broad-band station II Central r~ording facility ~---'""" 15 km zone around reservoir syst~m ' . 1~ 0 5 10 1!5 lO-.\\~~ e=s I 0 10 20 30 ~·~~'" GENERAL CONFlGURATION OF THE .PROPOSED ' •• ~ ' -<'. LONG TERJVI SEISMIC NETWORK FlGURE 1.26 ------'---DR--- ~ Qi ~ l. l RELATIVE DENSITIES OF MOOSE-NOVEMBER, l980 0 UPPER SU Sl TIJIJ{(J WATERSHED BOJUNIJANY LEGEND ----CENSUS J).REA D ZERO 0£-NSITY LOW O;~'SITY k~~~ MEDlU~t -b"ENStTY ~ HIGH DENSiTY 20 SCALE IN MILES FiGURE 7.27 40 ----1111111 I MODWfEO FROM SKOOG 1968 , \'· ----· --·--- - tr1) --- A S K A WRANGELL MTS \ \ \~. . ""'·· \ '"' l . .I DIVISIONS O.F NELCHINA CARIBOU HERD RANGES (UNITS BASED UPON TOPOGRAPHY, VEGETATION AND USE) 0 25 50 r: •· I Z"i!iil SCALE-MILES-APPRO)tiMATE FlGURE 7.28 ._----------------------------------------------------------------------~--~--·---·~--------------------,--------~ . . . i' ---•: • - - - -.• - - -~---·-· "":~ LOCATION AND TERRITORIAL BOUNDARIES OF WOLF PACKS -1980 UPPER SUSITNA; WATERSHED 801/N/JJfMlY · LEGEND m WATANA ~l< ~· TYONE. PACK [illliU SUSlTNA ~ACt< I§ TOLSO~A PACK r--, L_J SUSPEC1'En PACK 0 20. ----SCALE IN MILES Ftnu~. -o-1· · ~9 .~ • ..,u •• -···' 40 "" - -· c~ I I - I I I I I I I •• I I I I I .i I I l l .......,__ ...... -0 UJ c >- 0 .J 0.. :e 1.1.1 &.1.. 0 (I) 0 % < (I) ::> 0 X t-- 200 f50 tOO 50 EMPLOYMENT LEGEND -STATE --RAIL BELT 1970 11 12. 73 74 75 76 11 1a 79 ao 4,5Q -400 kJ .J 0.. 0 UJ 350 0.. lL. 0 t/) 0 z <t (I) ::::> 0 ::z: 300 2.50 .... -200 ,-- (YEAR) POPULATION // ,-------- I' / I I ---- t970 11 12 73 74 75 76 77 1a 79 so -t/) 0: <: .J -1 0 0 1.2 lb 8 (YEAR) PER CAPITA PERSONAL INCOME ' ..-. /---::.::__~ /.~ h lL. 6 0 til 0 z <t til ::> 0 :i: t--. I t I I I ) 1970 11 12 73 74 75 76 77 78 79 eo (YEAR) EMPLOYMENT, POPULATION AND PER CAPITA PERSONAL INCOME lN~ THE STATE OF ALASKA AND RA1L BELT REGION,I970-t980 FIGURE 7.30 " .. 't'.,._.,..,~ .... .....-.....,_.,..___.....,........~-------- ' ' ;a I II I I ••• ,I 1 •• 1 !I ~ 3500 Et.IPLOY-MENT -Q LLI >-2500 g 0.. LEGEND 2 --LLI 2000 0 ~ MAT SU BOROUGH "" o. --VALDEZ-WHITTIER-1500 en CHITINA CENSUS DIV1SION a:: LlJ 1000 £D :e ::) z 500 - ' I . J ~.,~~, 1970 71 72 73 74 75 76 77 78 79 80 .. (YEAR) " 20 ~OPULATlON -LlJ ...J 0.. 0 l.tJ 0.. "" 0 en Q 2 <( (I) ::) 0 ::X: .... - s 1970 71 72 73 74 75 76 77 78 79 80 (YEAR) PER CAPITA PERSONAL INCOME 1\ -20 I \ (/) I \ a:: <( 16 I \ .J ....I I \ 0 / ' / 0 12 / LL. / 0 / (/) 8 / 0 ./ z _ ....... <( --(/) 4 -::) 0 :C. i._l I .... -1970 71 72 73 74 75 76 77 73 '(,9 80 {YEAR) EMPLOYMENT, POPULATION AND PER CAPITA PERSONAL lNCOME IN THE MATANUSKA-SUSITNA BOROUGH AND VALDEZ~ WHITTIER-CHITINA CENSUS DIVISION, 1970 -1980 FIGURE. 7 .3 f [iil I I I ·I I I i I I I I ·I I I I •• I il . IJ :· !t --~~.·--,~----------------------~------------------------------------~--------------------~~ EXI STINe STRUCTURE (S) • • • • A. · IGHWAY l SCALE EXIS~fiNG STRUCTURES ~ . ~------------~-----------------------------,------------~--~------~----~----------~--------------~--~----~----0----~F~IG~. U~R~E~·.·-~7~~~2~·-=UIIuu=·=ll~,~~····· ._.illlli ________ -* ____________ l!iillll_..-. _____ ...... _._.,. _____ _. _ _.~ .. --,•~•.:;z~•lfil-.__r_..•.•··illllil·--•s~~~ ...... ~------~~~~~~----1!1111111---.--.. ------------• I I I, I •• I I I I I I I I I •• I I I I ""'' I '--"~~' KEETNA ,.., }I \ ... _,-, I '.I - LAND USE AGGREGATIONS SCALE NO. '· 2& 3. 4. 5. 6. 7. a. 9. JO •. 11. 0 ·=· ·~ USE INTENSITY ~£CREATION MEDlU.M MINING MEDlUM RECREATION MEDIUM MINING/RESIO HIGH MINING HIGH REC./RESID HIGH RECREATION HIGH RECR~ATION LOW RECREATION MEDIUM RECREATION ·MEDIUM RECREATION LOW 10 20 MIL~S . I I I I. I I I I I I I I I I I I I I •• 8 -SUSITNA BASIN DEVELOPMENT SELECTION This sect ion of the report out 1 i nes the engi ne.eri ng and p l arni ng studies carried out as a basis for formulation of Susitna Basin development plans and selection of the preferred plan. The recommended plan, the Watana/Devil Canyon dam project, is compared to alternative methods of providing the Rai lbelt energy needs inc 1 udi ng therma 1 and other potentia 1 hydroe lect ric deve 1 opments outside the Susitna Basin on the basis of technical, economic, environmental, and social aspects. In the description of the planning process, certain plan components and process- es are frequently discussed. It is appropriate that three particular terms be c 1 early defined: {a) Oamsite -An individual potential darn.site in the Susitna Basin, equivalent to 11 alternativ-4' and referred to in the generic process (\S 11 candidate." {b) Basin Development - Plan A plan for developing energy within the basin involv- ing one or more dams, each of specified height·, and corresponding power plants of specified capacity. {c) Generation Scenario Each plan is identified by a plan number and subnumber indicating the staging sequence to be followed in developing the full potential of the plan over a per- iod of time. - A specified sequence of implementation of power gen- eration sources c apab 1 e of pro vi ding sufficient pO\\Ier and energy to satisfy an electric load growth for-ecast for the 1980-2010 period in the Railbelt area. This sequence may include different types of generation sources such as hydroe 1 ectri c and coa 1, gas or oi 1- fi red therma 1. These generation scenarios are re- quired for the comparative evaluations of Susitna Basin generation versus alternative methods of genera- tion. 8.1 -Plan Formulation and Selection Methodology In the formulation of the generic plan and selection methodology, five basic steps are required; defining the objectives, selecting candidates, screening, formulation of development plans, and:: finally, a detailed evaluation of the plans. The objectives are essentially twofold. The first is t~ determine the optimum Susitna Basin.development plan, and the second is to undertake a preliminary assessment of the feasibility of the selected plan by comparison with alternative methods of generating energy. The various steps required are outlined in subsections of this section. 8-1 Throughout the planning process, engineering layout studies were made to refine the cost estimates for power generation facilities or water storage development at several damsites within the basin. These data were fed into the screening and plan formulation and evaluation studies~ The second objective, the detailed evaluation of the various plans, is satisfied by comparing generation scenarios that include the selected Susitna B.J.sin development pla11 with alternative generation scenarios including ·all-therm·al and a mix of thermal plus alternative hydropower developments. 8.2 -Damsite Selection In previous Susitna Basih studies, twelve damsites have been identified in the upper portion of the basin, i.e., upstream from Gold Creek. These sites are listed in Table 8.1 with relevant data concerning facilities, cost, capacity, and energy. The longitudinal profile of the Susitna River and typical reservoir levels associated with these sites is shown in Figure 8.2. Figure 8.3 illustrates which sites are mutually exclusive, i.e., those which cannot be developed ·jointly, since the downstream site vmuld inundate the upstream site. All relevant data concerning dam type, capital cost, power, and energy output were assemb 1 ed and are summarized in Tab 1 e 8 .1. For the Devi 1 Canyon, High Devil C~nyon, Watana, Susitna III, Vee, Maclaren, and Denali sites, conceptual engineering layouts were produced and capital costs were estimated based on calculated quantities and unit rates. Detailed analyses were also undertaken to assess the power capability and energy yields. At the Gold Creek, Devil Creek, Maclaren, Butte Creek, and Tyone sites, no detailed engineering or energy studies were undertaken; data from previous studies were used with capital cost estimates updated to 1980 levels. Approximate estimates of the potential average energy yield at the Butte Creek and Tyone sites were undertaken to assess the relative importance of these sites as energy producers. The data presented in Tab 1 e 8 ~ 1 show that De vi 1 Canyon, High De vi 1 Canyon, and Watana are the most economic 1 arge energy producers in the basin. Sites such as Vee and Susitna III have only medium energy production, and are slightly more cdstly than the previously mentioned damsites. Other sites such as Olson and Gold Creek are competitive provided they have additional URstream regulation. Sites such as Den a 1 i and r~ac l aren produce substantia 11 y higher cost energy than the other sites but can also be used to increase regulation of flow.for downstream use. For comparative purposes, the capital cost estimates developed in recent pre- vious studies, updated to 1980 values, are ·listed alongside the costs developed for the current studies (Table 8.2). These results show that the current esti- mates are generally slightly higher than previous estimates and, except in the case of Vee, differences are within 15 percent. 8-2 I I I I I I I I I I I ~·· I I •• I I I I, I I I I I I I I I •• I I I I I I I •• _, At Devil Canyon, current total development costs were found to be similar to the 1978 COE estimates. Although the estimates i nvo 1 ve different dam types, current studies have indicated that at a conceptual level the cost of development at this site is not very sensitive to dam type. The results in Table 8.2, there- fore, indicate relative agreement. Costs developed for the High Devil Canyon damsite are very close, while those at Watana exceed previous estimates by about 15 percent. A major difference occurs at Vee where current estimates exceed those developed by the COE by 40 percent~ A large portion of this difference can be ascribed to the greater level ·of detail incorporated jn the current studies as compared to the previous work and assumption that more extensive foundation excavation and treatment would be required. This additional founda- tion work is consistent with a standard set of design assumptions used for developing all the site layouts reported here. 8.3 -Site Screening The objective of this screening process was to eliminate sites which would obviously not feature in the initial ~tages of a Susitna Basin development plan and which, therefore, did not deserve further study at this stage. Three basic screening criteria were used: environmental, alternative sites, and energy contribution. (a) Screening Criteria (i) Environmental The potential impact on the environment of a reservoir. located at each of the sites was assessed and categorized as being relatively unacceptable, significant, or moderate. -Unacceptable Sites Sites in this category are classified as unacceptable because either their impact on the environment would be extremely severe or there are obviously better alternatives available. Under the. current circumstances, it is expected that it would not be possible to obtain the necessary agency approval, permits, and licenses to develop these sites. The Gold Creek and Olson sites both fall into this category. As salmon are known to migrate up Portage Creek~ a deve 1 opment at either of these sites would obstruct this migration and inundate spawning grounds. Available information indicates that salmon do not migrate through Devil Canyon to the river teaches beyond because of the steep fall and high flow velocities. Development of the mid-reaches of the Tyone River would result in the inundation of sensitive bi-g game and waterfowl areas, provide access to a large expanse of wilderness area, and contribute only a small amount of storage and energy to any Susitna development. Since more acceptable alternatives are obviously available, the Tyone site is also considered unacceptable . 8.-3 ,:,~-~:,. ,_,,,...: .. """-~·'~"" !-,,~,.: ~" •• '""~"""" ... ·-·~'·· ·-~-~ ;..,. _ .. ~·· •• ~ ..... ~·._.·.·.~~··o<-·-r~ -""'"""~"'··""'--· -~,-·~·- c -Sites With Significant Impact Between Devil Canyon and the Oshetna River, the Susitna River is confined to a relatively steep river valley. Upstream from the Oshetna River the surrounding topography flattens, and any development in this area has the potential of flooding large areas~ even with relatively low dams. The area is very sensitive in terms of potential impact en big game and waterfowl. The sites at Butte Creek, Denali~ Maclaren, and, to a lesser extent Vees fit into this category. -Sites With Moderate Impact ' .... " ,I· I I I I Sites between Oevi 1 Canyon and the Oshetna River have a lower potential environmenta.l impact. These sites include the Devil •. -Canyon, High Devi 1 Canyon, Devi 1 Creek, Watana and Susitna sites, ands to a lesser extent the Vee site. (i1) Alternative Sites Sites which are close to each other and can be regarded as alterna- tive dam locations were treated as one site for project defin1tion study purposes. The two sites which fa 11 into this category are Oevi 1 Creek, an alternative to the High Devi 1 Canyon site, and Butte Creek, an alternative to the Denali site. (iii) Energy Contribution The total Susitna Basin potential energy production has been assessed at 6, 700 GWh. Forecast future energy requirements \'f'ithi n the Railbelt region for the period 1980 to 2010 range from 2,400 to 13,100 GWh. It was therefore decided to limit the mini mum size of any power development in the Sus·itna Basin to an average annual energy production in the range of 500 to 1,000 GWh. The upstream sites such as Maclaren, Denali; Butte Creek, and Tyone do not meet this mini mum energy gene.rati on criterion. (b) Screeni~g Process The screening process involved eliminating all sites falling in the un- acceptable environmental impact and alternative site categories. Those failing to meet the energy contribution criteria were also eliminated un- less they had some potential for upstream regulation. The results of this process are as follows: -The 11 Unacceptable site" environmental category eliminated the Gold Creek, Olson, and Tyone sites. -The alternative sites category eliminated the Devi 1 Creek and Butte Creek sites~ 8-4 I I •• I' I I I I I I I I I. I I I I. I I I I I, I I I I I I I I I ;I -No additional sites were eliminated for failing to meet the energy contribution criteria. The remaining sites upstream from Vee, i.e., r~ac 1 aren and Dena 1 i, \'lere retained to insure that further study be directed toward determining the need and viability of providing flow regulation in the ·headwaters of the Susitna. 8.4 -Engineering Layouts In order to obtain a uniform and reliable data base for studying the seven sites r ema 1 n1 ng, it was necessary to develop engineering 1 ayouts and reevaluate the costs. In addition, staged developments at several of the larger dams were studied. The basic objective of these layout studies was to establish a unifor·m and con- sistent development cost for each sit e. These 1 ayouts are consequently concep- tual in nature and do not necessarily represent optimum project arrangements at the sites. Also, because of the lack of geotechnical information at several of the sites, judgmental decisions had to be made on the appropriate foundation and abutment treatment. The accuracy of cost estimates made in these studies is probably plus or minus 30 percent. (a) Design Assumptions In order to maximize standardization of the layouts, a set of basic design assumptions was developed. These assumptions covered geotechnical, hydro- 1 ogic, hydraulic, civil, mechanical, and electrical considerations· and were used as guidelines to determine the type and size of the various components within the overall project layouts. As stated previously, other tha.n at Watana, Devil Canyon, and Denali, little information rega·rding site condi- tions was available. Broad assumptions were made on th~ basis of the limited data, and those assumptions and the interpretation of data have been conservative. . It was assumed that the relative cost differences between rockfill and con- crete. dams at the sites would either be marginal or greatly in favor of the rockfill. The more detailed studies carried out subsequently for the \~at ana and De vi 1 Canyon site support this assumption. Therefore, a rock- fill dam has been assumed at all developments in order to eliminate differ- ent cost discrepancies' that might result from a consideration of dam-fill rates compared to concrete rates at alternative $ites. (b) General Arrangements A brief description of the general arrangements developed for the various sites is given below. Plates 2 to 8 illustrate the layout details. Table 8.3 summarizes the crest levels and dam heights considered. In 1 ayi ng out the developments, Conservative arrangements· have been adopted, and whenever possible there has been a general standardization of the component structures. 8-5 ( i) De vi 1 Canyor_ (Plate 2) -Standard Arrangement The deve-lopment at Devil Canyon located at the upper end of the canyon at its narrO\'/est point consists of a rockfill dam, single spillway, power facilities incorporating an underground power- house, and a tunnel diversion. The rockfill dam will rise above the valley on the left abutment and terminate in an adjoining saddle dam of similar construction. The dam will be 675 feet above the lowest foundation level with a crest elevation of 1470 and a volume of 20 million cubic yards involving an inclined impervious core, filter zones, and an over~ lying rockfill shell •. It is anticipated that the shell core and filter materials will be available locally. Contact grouting, curtain grouting, and drainage via a network of shafts and galler- ies was allowed for, and all alluvium and overburden material will· be removed from the shell foundation area .. Diversion wi 11 be effected by two concrete-1 i ned tunne 1 s driven within the rock on the right abutment. Upstream and downstream rockfi 11 cofferdams, with aqueous trench cutoffs, vJi 11 be founded on the river a 11 uvi urn and separated from the main dam. Fi na 1 closure will be achieved by lowering vertical lift sliding ga .. t.eS housed in an upstream structure fo 11 owed by construction of a solid concrete plug within the tunnel in line with the main dam grout curtain. Subsequent controlled downstream releases will occur via a small tunnel bypass located at the gate structure and a fixed co~e discharge valve housed within the concrete plug. The spillway \'/ill be located on the right bank and will consist of a gated overflow structure and a concrete-lined chute linking the overflov1 structure with intermediate and termina.l stilling basins. Sufficient s pi 11 way capacity wi 11 be provided to pass the· Probable Maximum Flood safely. The power facilities will be located on the right abutment. The massive intake structure will be founded within the rock at the end of a deep approach channe 1 and \>Ji 11 consist of four integrated units, each serving individual tunnel penstocks. Each unit has three outlets at different levels allowing for various levels of drawoff and corresponding temperature control of releases from the seasonally fluctuating reservoir. The penstocks will be concrete-lined over their full length except for the section just upstream from the powerhouse \'lhi ch will be steel-lined to prevent seepage into the powerhouse area. The powerhouse wi 11 . house four 100-MW (or 150-f4W) vertically mounted Francis type turbines driving overhead 110 (165 MVA) umbrella type generators. The main power transformers will be housed in an underground gallery located above the draft tubes .• The control room and offices will be situated at the ,surface adja- cent to a surface switchyard. 8-6 I •• I I I I I I I I I I I I I .I I I I I I' •• i ,. I I :...;.' I I I I I I I I: I I ... I I I , -Staged Powerhouse As an alternative to the full power development in the first phase of construction, a staged powerhouse alternative was also investi- gated. The dam would be completed to its full height but with an initial plant installed capacity in the 200-to 300-NW range. The complete powerhouse would be constructed together \"'ith penstocks and a tailrace tunnel for the initial two 100-MW (or 150-MW) units, together with concrete foundations for the future units. (ii) Watana (Plates 3 and 4) -Standard Arrangement (see Plate 3) For initial comparative study purposes, the dam at Watana is assumed to be a rockfill structure located on a similar alignment to that proposed in the previou~ COE studies. It will be similar in construction to the dam at De vi 1 Canyon with an impervious core founded on sound bedrock and an outer shell composed of blasted rock excavated from a single quarry located on the left abutment. The dam will rise 880 ·feet from the lowest point on the foundation and have an overall volume of approximately 63 million cubic yards for a crest elevation of 2225. · The diversion will consist of twin, concrete-lined tunnels located within the rock of the right abutment. Rockfill cofferdams, also with impervious cores.and appropriate cutoffs, will be founded on the a 11 uvi urn and separated from the rna in dam. Diversion c 1 os ure and facilities for downstream releases will be provided for in a manner similar to that at Devil Canyon. The spillway will be located on the right bank and will be similar in concept to that at Devi 1 Canyon with an intermediate and term- inal stilling basin. The power facilities located within the left abutment with similar intake, underground ppwerhouse, and water pas·sage concepts to those at Devil Canyon will incorporate four 200-HW turbine/genera- tor units giving a total output of 800-MW • . -Staging Concepts· As an alternative to initial full development at Watana, staging alternatives were investigated. These included staging of both dam and powerhouse construction. Staging of the 9owerhouse would be similar to that at Devil Canyon, with a Stage I installation of 400-M~ and a further 400-MW in Stage II. 8-7. -Staged Powerhouse As an alternative to the full power development in the first phase of construction, a staged powerhouse alternative was also i nvesti- gated. The dam would be completed to its full height but with an initial plant installed capacity in the 200-to 300-MW range. The complete powerhouse would be constructed together with penstocks and a tailrace tunnel for the initial two 100--M~ (or 150-M\~) units, together with concrete foundations for the future units. (ii) ~tana (Plates 3 and 4) -Standard Arrangement (see Plate 3) For initial comparative study purposes, the dam at Watana is assumed to be a rockfill structure located on a similar alignment to that proposed in the previous COE studies. It will be similar in construction to the dam at Devil Canyon with ,an imper"/ious core founded on sound bedrock and an outer shell composed of blasted rock excavated from a single quarry located on the left abutment. The darn will rise 880 feet from the lowest point on the foundation and have an overall volume of approximately 63 million cubic yards for a crest elevation of 2225. The diversion will consist of tw:n, concrete-lined tunnels located within the rock of the right abutment. Rockfi 11 cofferdams, a1 so with impervious cores and appropriate cutoffs, wi 11 be founded on the alluvium and separated from the main dam. Diversion closure and facilities for downstream releases wi 11 be provided for in a manner similar to that at Devil Canyon. The spilh-Jay will be located on the right ba.nk and will be similar in concept to that at Devil Canyon with an intermediate and term- inal stilling basin. The power facilities located within the left abutment with similar intake, underground powerhouse, and water passage concepts to those at Devil Canyon will incorporate four 200-MW turbine/genera- tor units giving a total output. of 800-MW. ~ -Staging Concepts As an·alternative to initial full development at vJatana, staging alternatives were investigated. These included staging of both dam and powerhouse construction. Staging of the powerhouse would be similar to that at Devil Canyon, with a Stage I installation of 400-M\~ and a further 400-M~J in Stage I I. In order to study the alternative dam staginq concept it has been assumed that the dam would be constructed for a maximum operating water surface e 1 evat ion some 200 feet 1 O\'ler than that in the fi na 1 stage (see Plate 4). 8-8 ·!:~ -;; I I I ,I I I ...... I I I I I I I I I I '! I I I I I .. I I I I I I ·I I I I I I I I I' I " The first stage powerhouse \'lould be camp 1 ete ly excavated to its final size. Three oversized 135-M~~ units would be installed together with base concrete for an additional unit. A low level centro 1 structure and twin concrete-1 i ned tunne 1 s 1 eadi ng into a downstream stilling basin vmuld form the first stage spillway • For the second sta:ge, the dam would be completed to its full height, the impervious core would be appropriately raised and additional rockfill would be placed on the downstream face. It is assumed that before construction comnences the top 40 feet of the first stage dam would be removed to ensure the complete integrity of the impervious core for the taised dam. A second spillway control structure would be constructed at a higher level and would incorporate a dovmstream chute leading to the Stage I spil h'lay structure. The original spillway tunnels would be closed with concrete plugs. A new intake structure would be constructed util- izing existing gates and hoists, and new penstocks would be driven to connect with the existing ones. The existing intake waul d be sealed off. One ·additiona\l 200 MW unit would be installed and the required additional penstock and tailrace tunnel constructed. The existing 135-MW units \-JOuld be upgraded to 200 MW. (iii) High Devil Canyon (Plate 5) . The deve 1 opment wi 11 be located between De vi 1 Canyon and Watana. The 855 feet high rockfill dam will be similar in design to Devil Canyon, containing an estimated 48 million cubic yards of rockfill with a crest elevation of 1775. The left bank spillway and the right· bank powerhouse fac·il iti es will also be similar in concept to Devil Canyon, with a_n installed capacity of 800-M\-Jo Two stages of 400-t1W were envisaged in each v1hi ch \'IOUl d be under- taken in the same manner as at De vi 1 Canyon, with the dam initially constructed to its full height. (iv) Susitna III (Plate 6) The development \vill be comprised of a rockfill darn with an imper- vious core approximately 670 feet high, a crest e lev at ion of 2360, and a volume of approx·imately 55 mi1lion cubic yards. A concrete- 1 i ned spi 11 way chute and a single sti 11 i ng basin and wi 11 be located on the right bank. A powerhouse of 350-MW capacity will be located underground and the two diversion tunnels on the left bank. (v) Vee (Plate 7) A 610 feet high rockfill dam founded on bedrock with a crest eleva- tion of 2350 and total volume of 10 million cubic yards was consid- ered. Since Vee is located further upstream than the other major sites the flood flows are correspondingly lower, thus allowing for a reduction in size of the spillway facilities. A spilh1ay utilizing a gated overflow structure, chute, and flip bucket was adopted. 8-9 . . . . • . . -. ;p t " . . -.. . ,. . • • '• • ', • • I I The power facil it~ es wi 11 consist of a 400-MW underground powerhouse •• . located in the left bank with a tailrace outlet \'le11 downstream of the main dam. A secondary rockfill dam will also be required in this vicinity to seal off a low point. Two diversion tunnels \till be provided on the right bank. ·- {vi) Maclaren (Plate 8) (vii) The development wi 11 consist of a 185 feet high earthfi 11 dam found- ed on pervious riverbed materials ... Crest elevation will be 2405 .. This reservoir will essentially be used for regulating purposes. Diversion will occur through three conduits located in an open cut on the left bank and floods will be discharged via a side chute spillway and stilling basin on the right bank .. · Denali (Plate 8) .. Denali is similar in concept to Maclaren. The dam \·till be 230 feet high, of earthfi11 construction, and will have a crest.e1evation of 2555. As for Maclaren, no generating capacity was to be included. A combined diversion and spi 11 way faci 1 ity wi 11 be provided by twin concrete conduits founded in open cut excavation in the right bank and discharging into a common st i 11 i ng basin. 8.5 -fapital Cost For purposes of initial comparisons of alternatives, construction quantities were determin-ed for items comprising the major works and structures at the sites. Where detail or data were not sufficient for certain work, quantity estimates have been made based on previous Acres• experience and the general. knm'lledge of site conditions reported in the literature. In order to determine total capital costs for various structures, unit costs have been developed for the items measured.. These have been estimated on the basis of reviews of rates used in previous s~udies, and of rates used on similar works io Alaska and else- where. Where applicable, adjustment factors based on geography, climate~ man- power and accessibility were used. Technical publications have also been re- viewed for basic rates and escalation factors. An overall mobilization cost of 5 percent has been assumed and camp and catering costs have been based on a preliminary reviev-1 of construction manpower and schedules. An annual construction period of 6 months has been assumed for placement of fill materials and 8 months for all other operations.· Night work has been assumed throughout. A 20 percent allowance for non-predictable contingencies has been added as a lump sum together with a typi ca 1 allowance for large projects of 12 percent for engineer1ng and administration costs. The total capital costs developed are shown in Tables 8.1, 8.2, and 8.4 • It should be noted that the capital costs for Maclaren and Denali shown in Tables 8.1 and 8.2 have been adjusted to incorporate the costs of generation plants with capacities of 55-MW and 60-MW, respectively. 8-10 I I I I I. I I 1 I I I I I I I I I I I I I I .... I I I I •• ' I I I 'I ' I I 8.6 -Formulation of Susitna Basin Development Plans The results of the site screening exercise described in Section 8 .. 3 indicate that the Susitna Basin development plan should incorporate a combination of sever a 1 major dams and pO\-Jerhouses 1 ocated at one or more of the fo 11 owing sites: -Devil Canyon; -High Devil Canyon; -~~at ana; -Susitna III; or -Vee. Supplementary upstream flow regulation could be provided by structures at: -Maclaren; and Denali. A computer assisted screening process identified the plans that are most econom- ic as those of De vi 1 Canyon/Hatana or High De vi 1 CanyonjVee. In addition to these two basic development plans, a tunnel ~cheme which provides potential environmental advantages by replacing the Devil Canyon dam with a long power tunnel and a development plan involving the two most economic damsites, High De vi 1. Canyon and \~atana, were· a 1 so introduced.. · The criteria used at this stage of the process for selection of preferred Susit- na Basin development plans are mainly economic (see Figure 8.1). Environmental considerations are incorporated into the further assessment of the p 1 ans finally selected • The results of the screening process are shown in Table 8.5. Because of the simplifying assumptions that were made in the screening model, the three best solutions from an economic point of view are presented here. The most important conclusions that can be drawn are as follows: -For energy requirements of up to 1, 750 Gwh, the High Devil Canyon, Devil Can- yon or the Watana sites i ndi vi dually provided the most economic energy. The difference between the costs shovm on Table 8.5 is around 10 percent, \~bich is simi 1 ar· to the accuracy that can be expected from the screening m.odel. -For energy requirements of between 1, 750 and 3, 500 Gttlh, the High Devil Canyon site is the most economic. Developments at Watana and Devil Canyon are 20 to 25 percent more costly. ' · -For energy requirements of between 3,500 and 5,250 Gwh the combinations of either Watana and Devi 1 Canyon or High De vi 1 Canyon and Vee are the most economic. The High Devil/Susitna III combination is also competitive. Its cost exceeds the Hatana/Devi 1 Canyon opt i or by 11 percent, \·lhi ch is within the accuracy of the model. · -The total energy production capabi 1 ity of the Watana/Devi 1 Canyon developments is considerably larger than that of the High Devil Canyon/Vee alternative and. is the only plan capable of meeting energy demands in the 6,000 Gwh range. 8-11 ~:1 (a) Tunnel Scheme A scheme irivolving a long power tunnel could conceivably be used to replace the De vi 1 Canyon dam in the Hatana/Devi 1 Canyon Sus itna development p 1 an .. It caul d develop similar head for power generation at costs comparable to the Devil Canyon dam development, and may provide some environmental advan- tages by avolding inundation of Devil Canyon. Obviously, because of the low winter flows in the river, a tunnel alternative could be considered only as a second stage to the Watana development. Conceptually, the tunnel alternatives would comprise the following major components in some combination, in addition to the VJatana dam reservoir and associated powerhouse: -Power tunnel intake works; -One or two power tunnels of up to forty feet in diameter and up to thirty miles in length; - A surface or underground powerhouse with a capacity of up to 1,200 MW; - A re-regulation dam if the intake works are located downstream from \~at ana; and -Arrangements for compensation for 1 ass of flow in the bypassed river reach. Four basic alternative schemes were developed and studied. All schemes assume an initial Watana development with full reservoir supply level at Elevation 2200 and the associated powerhouse with an installed capacity of 800 ~1W. Table 8.6 lists all the pertinent technical information; Table 8.7 lists the energy yields and costs associated with these four schemes. Based on the foregoing economic information, Scheme 3 produces the lowest cost energy. A review of the environmental impacts associated with the four tunnel schemes indicates that Scheme 3 would have the least impact, primarily because it offers the best opportunities for regulating daily flows down- stream from the project. Based on this assessment, and because of its eco- nomic advantage, Scheme 3 was selected as the most appropriate. The capi- tal cost estimate appears in Table 8.8. The estimates ~;so incorporate single and double tunnel options. For purposes of these studies, the double tunnel option has been selected because of its superior reliability. It should also be recognized that the cost estimates associated with the tunnels are probably subject to more variation than those associate~ with the dam schemes due to geotechnical uncertainties. In an attempt to com- pensate for these uncet"ta inti es, economic sensitivity ana lyses using both higher and lower tunnel costs have been conducted. 8-12 f . ' . -. I I I • I lj, I 'I I I I l 11 I I I I I I I I I •• ':~·~ • • 1 ' • I ' I -..:: .. I I 'I I I I I I ' I -..... I I I. I ' I 0 (b) Additional Basin Development Plan As noted above, the Hatana and High Devil Canyon damsites appear to be in- dividually superior in economic terms to all others. An additional plan was therefore developed to assess the potential for developing these two sites together~ For this scheme, the Watana dam would be developed to its full potentia 1. However~ the High Dev i 1 Canyon dam waul d be constructed to a crest elevation of 1470 to utilize fully the head downstream from Watanal' (c) Selected Basin Development Plans The essential objective of this step in the development selection process is defined as the identification of those plans which appear to warrant further, more detailed evaluation. The results of the final screening pro- ce~s indicate that the Watana/Devil Canyon and the High Devil Canyon/Vee plans are cleai··!y superior to all other dam combinations. In addition, it was decided to study further the tunnel scheme uS an alternative to the Watana/High Devil Canyon plan. Associated with each of these plans are several options for staged develop- ment, including staged construction of the dams and/or the power generation facilities. For this more detailed analysis of these basic plans, a range of different aproaches to staging the developments were considered. In order to keep the total options to a reasonable number and also to maintain reasonably large staging steps consistent wit~ the tot a 1 deve 1 opment size, staging of only the two larger developments, i.e., Watana and High Devil Canyon, was considered. The basic staging concepts adopted for these developments involved staging both dam and powerhouse construction, or alternatively just :staging po\~erhouse r;onstructi on. PovJerhouse stages are considered in 400 MW increments. Four basic plans and associated subplans are summarized in Table 8.9 and are briefly described below. Plan 1 involves the Watana-Devi1 Canyon sites, Plan 2 the High Devil Canyon-Vee sites, Plan 3 the \4atana-tunn.e1 concept, and Plan 4 the Watana-High Devil Canyon sites. 8.7 -Evaluation of Basin Development Plans The overall objective of this step in the evaluation process was to select the preferred ·basin development plan. A preliminary evaluation of plans was ini- tially undertaken to determine broad c.omparisons of the available alternatives. This \'las followed by appropriate adjustments to the plans and a rr0re detailed evaluation and comparison. · (a) freliminary Evaluations Table 8.9 lis~s pertinent details such .as capital costs, construction per- iods and energy yields associated v1ith the selected plans. The energy yield information was developed using a multireservoir computer model. This model simulates, on a monthly basis, the energy production from a given system of reservoirs for the 30-year period for which streamflo\'1 data are available. It incorporates daily'peaking operations if these are required to ge.nerate the necessary peak capacity. A 11 the model runs incorporate preliminary environmental constraints. Seasona 1 reservoir 8-13 dra\•ldmoJns ·are 1 imited to' 150 feet for the larger and 100 feet for the smaller reservoirs; daily drawdovms for daily peaking operati'ons are limited to 5 feet and minimum discharges from each re$ervoir are maintained at all times to ensure all river reaches remain \'latered. These minimum discharges were set approximately equal to the seasonal average natural lm·1 flows at the damsites. · The model is driven by an energy demand \'.Jhich fo11ows a distribution cor- responding to the seasonal distribution of the total system load. The model was used to evaluate, for each stage of the plans described above, average and firm energy and the installed capacity for a specified plant factor. This usually required a series of iterative runs to ensure that the number of failures to provide required reservoir coverage in the 30-year period \tas limited to one year. The firm power was assumed equal to that delivered during the second 1 o\-Jest annua 1 energy yi e 1 d in the simulation period. This corresponds approximately to a 95 percent level of assurance. A range of sensitivity runs \vas c9nducted to explore the effect of the res- ervoir drawdown limitation on the energy yi_eld. The results of these runs are summarized in Table 8.10. They indicate that the drawdown limitations currently imposed reduce the firm energy yield for \~atana development by approximately 6 percent. (b) Plan Modifications In the process of evaluating the schemes, it became apparent that there would be environmenta1 4 problems associated with allowing daily peaking op- erations from the most downstream reservoir in each of the plans described above.. In order to avoid these potential problems while still maintaining operational flexibility to peak on a daily basis, re-regulation facilities were incorporated in the four basic plans. These facilities incorporate both structural measures such as re-regulation dams and modified operation- al procedures. Details of these modified plans, referred to as El to E4, are 1 i s ted i n Tab 1 e 8. 11. The plans listed in Table 8.11 are subjected to a more detailed analysis in the following section. (c) Evaluation Criteria and Methodology The approach to evaluating the various basin development plans described above is twofold: -For determining the optimum staging concept associated v1ith each basic plan (i.e. the optimum subplan), ~:mly economic criteria are used and the least cost staging concept is adopted. -For assessing which plan is the most appropriate, a more detailed evalua- tion process incorporating economic, environmental, social, and energy contribution aspects is taken into account. 8-14 • ' ' I .:;t I t I I I I I I ' I .._, I ' I ' t I A •. , I I I ,.. ' I I I I .... I ' I I a I- I l I ~- ' Economic evaluation of-any Susitna Basin development plan requires that the impact of the plan on the cost of energy to the railbelt area consumer be assessed on a systemwide basis. Since the consumer is supplied by a large number of different generating sources, it is necessary to determine the total Railbelt system cost in each case to compare the various Susitna Basin development options. The basic tool used to determine the system costs is a computet .. simulation/ planning model of the entire generating system; General Electric's Optimlzed Generation Planning Model (OGPS). Input to this model includes the following: -Load forecast over a specified period of time; -Load duration curves; -Details of the existing generating system; -A list of all potential future thermal generating sources with associated annualized costs, installed capacities, fuel consumption rates, etc.; -Fuel prices; - A specified hydroelectric development plan, i 4e. _the annualized costs, on-line dates, installed capacities, and energy production capability of the various stages of the plan; and -System reliability criteria. For current study purposes, a loss af load probabi 1 ity (LULP) of 0.1 day/ year is used. Utilizing the above information, the program simulates the performance of the system, incorporates the hydroelectric development as spe-cified~ and adds thet"'mal generating resources as necessary to meet the load growth and " to satisfy the reliability criteria. The thermal plants are selected so that the present worth of the total generation cost over the study p;t:riod ·;s minimized. The basic economic analyses undertaken in this study incorporated •~real 11 discount and escalation rates, and the parameters used are summarizerl in Table 8.12. A summary of the input data to the model and a discussion of the resltllts fallows. (d) Initial Economic Analyses Table 8.13 lists the results of the first series of economic analyses un- dertaken for the basic Susitna Basin development plans 1 isted in Table. 8.11. The information provided includes the specified online dates for the various stages of the plans, the OGP5 run index number, the total installed capacity at the year 2010 by category, and the tot a 1 system present North cost in 1980. A present worth cost is evaluated for the period 1980 to 2040. The OGP5 model is run for the period 1980-2010; thereafter steady state conditions are assumed and the then-existing generation mix and annual costs of 2010 are applied to the years 2011 to 2040. This extended period of time is necessary to ensure that the hydroelectric options being studied, many of which only come online around 2000, are simulated as . operating for periods approaching their economic lives and that their full impact on the cost of the generation system is taken into account. The highlights of the results in Table 8.13 can be summarized as follows: {i) Plan El-Watana-U~vil Canyon Staging the dam at Watana (Plan El. 2) is not as economic as constructing it to its full height (Plans E1.1 and E1.3). The economic advantage of not staging the dam amounts to $180 mill ion in 1980" -The results indicate that, with the level of analysis performed, there. is no discernible benefit in staging construction of the Watana powerhouse (Plans E1.1 and E1.3). It is considered likely, however, that some degree of staged powerhouse construct ion wi 11 ultimateiy be incorporated due to economic considerations and also to p~ovide maximum flexibility. For current planning purposes, it is therefore assumed that the staged powerhouse concept (Plan El.3} is the most appropriate Watana-Devil Canyon development p 1 an. Additional runs performed for variations of Plan El.3 indicate that system costs would incr~ase by ~1,110 million if the Devil Canyon dam stage were not constructed. Furthermore, a five year delay in construct ion of the Watana dam would increase system costs by $220 million. These increases are due to additional higher cost-·l:h-ermal units which must be brought on line to meet the forecast demand in the early 1990 • s. -Plan El.4 indicates that, should the powerhouse size at \~atana he restricted to 400 ~1W, the overall system cost would increase by $40 mill ion1 (ii) Plan E2-High Devil Canyon-Vee Plans E2.1 and E2.2 were not analyzed, since these are similar to E1.1 and E1.2 and similar results can be expected. -The results for Plan E2.3 indicate it is $520 million mar~ costly than Plan El.3. Cost increases also occur if the Vee dam staae is . .... not constructed. A cost reduction of approximately $160 million is possible if the Chakachamna hydroelectric project is constructed instead of the Vee dam. -The results of Plan E2.5 indicate that total system generating costs would go up by $160 million if the total capacity at High Dev i 1 Canyon were 1 imited to 400 MW. 8-16 I .... - ' ' I I I ' ' ' I t I I I I """" _, ,. ) I I I I I I I I ' I I I I I I ' I '., I (e) (f) (iii) ( i v) Plan E3 The results far Plan E3.1 illustrate that the tunnel scheme versus the Devil Canyon dam scheme (El.3) adds approximately $680 million to the total system cost. The availability of reliable geotechnical data would undoubtedly have improved the accuracy of the cost esti- mates for the tunnel alternative. For this reas~:m," a sensitivity analysis was made as a check to determine the effect of halving the tunnel costs. This analysis indicates that the tunnel scheme is still more costly by $380 million. Plan E4 The results indicate that system costs associated with Plan E4.1, excluding the Portage Creek site development, are $200 million more than the equivalent El plan. If the Portage Creek development is included, a greater increase in cost would result .. Economic Sensitivity Analyses Plans El, E2, and E3 were subjected to further sensitivity analyses to assess the economic impacts of various load growths. These results are summarized in Table 8.14. The results for low load forecasts illustrate that the most viable Susitna Basin development plans include the 800 MW plans (Plans E1.5 and E2.5). Of these two, the Watana-Devi 1 Canyon p 1 an is 1 ess costly than the High Devil Canyon-Vee plan by $210 million. Higher system costs are involved if only the first stage dam is constructed, (either Watana or High De vi 1 Canyon). In this case, the Hatana only plan is $90 million more cost1y than the High De vi 1 Canyon p 1 an. · · Plan E3 variations are more costly than both Plans El and E2. For the high load forecasts, the results indicate that the Plan E1.3 is $1040 million less costly than E2.3. The costs of both plans can be re- duced by $630 and $680 million respectively by ,;the addition of the Chaka- chamna development as a fourth stage. No further analyses were conducted on Plan E4. As envisaged, this plan is similar to Plan E1 with the·exception that the lm'/er main dam site is moved from Devil Canyon upstream to H~gh Devil Canyon. The initial analyses out- lined in Table 8.13 indicate this scheme to be more expensive. Evaluation Criteria The following criteria were used to evaluate the shortl isted bas'in develop- ment plans. They generally contain the requirements of the generic process with the exception that an additional criterion, energy contribution, is added in order to ensure that full consideration is given to the total basin energy potential developed by the various plans. 8-17 (g) ( i) E<:onomic ,. The parameter used is the tot a 1 present \'lOr th cost of the tot a 1 Railbelt generating system for the period 1980 to 2040 as listed in Tables 8.14 and 8.15. (ii) Envir6nmental A qualitative assessment of the environmental impact on the ecological, cultural, and aesthetic resources is undertaken for each plan. Emphasis is placed on identifying major concerns so that ·these could be combined with the other evaluation attributes in an overall assessment of the plan. ( i i i ) Socia 1 This attribute includes determination of the potential non-renewable resource displacement, the impact on the state and local economy, and the risks and consequences of major structural failures due to seismic events. Impacts on the economy refer to the effects of an investment plan on economic variables. (iv) Energy Contribution The parameter used is the total amount of energy produced from the s peci fi c deve 1 opment plan. An assessment of the energy deve 1 opment foregone is also undertaken. This energy loss is inherent to the plan and cannot easily be recovered by subsequent staged developments. Results of Evaluation Process The various attributes outlined above have been determined for each plan and are summarized in Tables 8.16 through 8.24. Some of the attributes are quantitative while others are qualitative. Overall evaluation is based on a comparison of similar types of attributes for each plan. In cases where the attributes associated with one plan all indicate equality or superior- ity with respect to another plan, the decision as to the best plan is clear cut. In other cases where some attributes indicate superiority and others inferiority, differences are highlighted and trade-off decisions are made to determine the preferred development plan. In cases \·th·ere these trade- offs have had to be made, they are relatively convincing and the decision making process can, therefore, be regarded as fairly robust. In addition, these trade-offs are clearly identified so the recorder can independently answer the judgement decisions made. The overall evaluation process is conducted in a series of steps. At each step~ only a pair of plans are evaluated. The superior plan is then passed on to the next step for evaluation against an alternative plan. 8-18 I I I ,, fl I I I ' I I I I I I I I ' I I I I I ' I I I I I I I I I I ' I ' I ( i ) Devil Canyon Dam Versus "funnel The first step in the process involves the evaluation of the Watana- Devil Canyon dam plan (E1.3) and the Watana tunnel plan (£3.1). Since Watana is common to both plans, the evaluation is based on a comparison of the Devil Canyon dam and tunnel schemes. In order to assist in the evaluation in terms of economic criteria, additional information obtained by analyzing the results of the OGP5 computer runs is shown in Table 8.16. This information illustrates the breakdown of the total ~ystem present \vorth cost in terms of capital investment, fuel, and operation and maintenance costs. E~onomic Comparison From an economic point of view, the Devil Canyon dam scheme is superior·. As surnnarized in Tables 8.16 and 8.17, on a present worth basis the tunnel scheme is $680 million (about 12 percent) more expensive than the dam scheme. For a low demand growth rate, this cost difference would be reduced slightly to $610 million. .Even if the tunnel scheme costs are halved, the total cost difference would still amount to $380 million. As highlighted in Table 8.17, consideration of the sensitivity of the basic economic evaluation to potential changes in capital cost estimate, the period 9f economic analysis, the discount rate, fuel costs~ fuel cost escalation, and economic plant lives do not change the basic economic superiority of the dam scheme over the tunnel scheme. -Environmental Comparison The environmental comparison of the two schemes is summarized in Table 8.18. Overall, the tunnel scheme is judged to be superior because: • It offers the potential for enhancing anadromous fish populations downstream of there-regulation dam due to the more uniform flow distribution that will be achieved in this reach; • It inundates 13 miles less of resident fisheries habitat in river and major tributaries; • It has a lower impact on wildlife habitat due to the smaller inundation of habitat by the re-regulation dam; • It has a lower potential for inundating archeological sites due to the smaller reservoir involved; and • It would preserve much of the characteristics of the Devil Canyon gorge which is considered to be an aesthetic and recreational resource. 8-19 . ( i i) -Social Comparison Table 8.19 summarizes the evaluation in terms of the social criteria of the two schemes. In terms of impact on state and 1ocal economics and risks due to seismic exposure, the two schemes are rated equally. However, the-dam scheme has, due to its higher energy yield, more potential for displacing nonrenewable energy resources, and therefore scores a slight overall plus in terms of the social evaluation criteria. -Energy Comparison Table 8.20 summarizes_the evaluation in terms of the energy contribution criteria. The results shown that the dam scheme has a greater potential for energy production and develops a larger portion of the basin's potentia 1. The dam scheme is therefor-e judged to be superior from the en~rgy contribution standpoint. Overall Comparison The overall evaluation of the two schemes is summarized in Table 8.21. The estimated cost saving of $680 million-in favor of the dam scheme is considered to outweigh the reduction in the overall environmental impact of the tunnel scheme. The dam scheme is therefore judged to be superior overall. Watana-Devi 1 Canyon Versus High De vi 1_ Canyon-Vee The second step in the development selection process involves an evaluation of the Watana-Devil Canyon (E1.3) and the High Devil Canyon-Vee (E2.3) development plans. -Economic Comparison In terms of the economic criteria (see Tables 8.16 and 8.17) the Watana-Devil Canyon plan is less costly by $520 million .. As for the dam-tunnel evaluation discussed above, consideration of the sensitivity of this decision to potential changes in the various parameters considered (i.e._ load forecast, discount rates3 etc.) does not change the basic superiority of the Hatana-Devil Canyon Plan. -Environmental Comparison The evaluation in terms of the environmental criteria is summar- ized in Table 8.22. In assessing these plans, a reach by reach comparison is made for the section of the Susitna River between Portage Creek and the Tyone River" The Watana-Devi 1 Canyon scheme would create more potentia 1 environmenta 1 impacts in the Watana Creek area. Hm-Jever, it is judged that the potential environmen- ta 1 impacts which waul d occur in the upper reaches of the river with a High Devi 1 Canyon-Vee development are more severe in comparison overall. 8-20 I I I ,a ' I I I ' I I ' ' I I t ,I . ... ,.' .. ·- I ... I I I~ --.-. ' I I ' I ,.._ •• I I I I I I I I I " From a fisheries perspective" both schemes vlould have a similar effect on the dm-Jnstrearn ar'ladromous fisheries although the High Devil Canyon-Vee scheme ·would produce a slightly greater impact on the.resident fisheries in the Upper Susitna Basin. The High Devil Canyon-Vee scheme 'dould inundate approximately 14 percent {15 miles) more critical ~'linter river bottom moose habitat than the Watana-Devi 1 Canyon scheme. The High De vi 1 Canyon .... Vee .scheme would inundate a large area upstream of the Vee site utilized by three subpopulation of moose that range in the north- east section of the basin. The Watana-Devil Canyon scheme would avoid the potential impacts on moose in the upper section of the river; however~ a larger percentage of the Watana Creek basin would be inundated. The condition of the subpopulation of moose utilizing this Watana Creek Basfn and the qua 1 i ty of the habitat appears to be decreasing. Habitat manipulation measures could be implemented in this area to improve the moose habitat. Nevertheless, it is considered that the upstream moose habitat losses associated with the. High Devil Canyon-Vee scheme would probably be greater than the Watana Creek 1 asses associated with the \~atana-Dev i 1 Canyon scheme. A major factor to be considered in comparing the two development plans is the potential effects on caribou in the region. It is judged that the increased length of river flooded, especially upstream from the Vee dam site, would result in the High 0~\1il Canyon-Vee plan creating a greater potential diversion of the Nelchina herd 1 s range. In addition, a larger area of caribou range would be directly inundated by the Vee reservoir. The area flooded by the Vee reservoir is also considered important to some key furbearers, particularly red fox. In a comparison of this area with the Watana Creek area that would be inundated with the Watana-Devil Canyon scheme, the area upstream of Vee is judged to be more important for forbearers. As previously mentioned, the area between Devil Canyon and the Oshetna River on the Susitna River is confined to a relatively steep river valley. Along these valley slopes are habitats important to birds and b 1 ack bears. Si nee the ~vat ana reservoir would flood the river section between the Hatana Dam site and the Oshetna River to a higher elevation than would the High Devil Canyon reservoir (2,200 feet as compared to 1, 750 feet), the High Devil Canyon-Vee plan would retain the integrity of more of this river valley slope habitat.· From the archeological studies done to date, there tends to be an increase in site intensity as one progresses tmtards the northeast sect~ on of the Upper Sus itna Basin. The High Devi 1 Canyon-Vee plan would result in more extensive inundation and increased access to the. northeasterly section of the basin. This plan is therefore judged to have a greater potential for directly or indirectly affecting archeo~ogical sites. 8-21 (iii) Due to the wi 1 derness"-ncrture 0 of the Upper Susitna Bas in, the crea- tion of increased access associated viith project development cou 1 d have a significant influence on future uses and managem~nt of the area. The High Devil Canyon-Vee plan would involve the construc- t ion of a dam at the Vee site and the ere at ion of a reservoir in the more northeasterly sectinn of the basin. This plan would thus create inherent access to more wilderness than would the Watana- Devil Canyon scheme. Since it is easier to extend access than to limit it, inherent access requirements ar~ considered detrimental and the ~{atana-Devil Canyon scheme is judged to be more acceptable in this regard. Except for the increased loss of river valley, bird, and black bear habitat, the Watana-Dev.il Canyon development plan is judged to be more environmentally acceptable than the High De vi 1 Canyon.- Vee plan. Although the Watana-Devil Canyon plan is considered to be the more environmentally compatible Upper Susitna development plan, the actual degree of acceptability is a question being addressed as part of ongoing studies. Energy Comparison The evaluation of the t\'.JO plans'in terms of energy contribution criteria is summarized-in Table 8.23. The Watana-Devil Canyon scheme is assessed to be superior due to its higher energy poten- tial and the fact that it develops a higher proportion of the basin's potential. -Social Comparison Table 8.19 summarizes the evaluation in terms of the social cri- teria. As in the case of the dam versus tunnel comparison~ the Watana-Devil Canyon plan is judged to have a slight advantage over the High Devil Canyon-Vee plan. This is because of its greater potential for displacing nonrenewable resources. Overall Comparison The overall evaluation is summarized in Table 8.24 and indicates that the Watana-Devi 1 Canyon plans are generally superior far all the evaluation criteria. Preferred Susitna Basin Development Plan Comparisons of the ~~atana-Dev11 Canyon plan with the Hatana-tunne 1 plan and the High Devil Canyon-Vee plans are judged to favor the Hatana-Devil Canyon plan in each case. The Watana-Devi 1 Canyon plan is therefore selected as the preferred Susitna Basin development plan, as a basis for continuation of more detailed design optimization and environmental studies. 8-22 I ..... I I I ' f ' ' I I I I I I ., I I ' l I I I I I I I I I I I I I I I I I· I \I 8.8 -On-Line Schedule The project schedules have been developed to allow substantial power production capabi 1 ity at \~at ana by December 1993 and comp1 ete capabi 1 ity at Oevi 1 Canyon py October 2002. 8-23 TABLE 8.1: POTENTIAL HYI)HOELECTRIC DEVELOPMENT Average £conomic1 Dam Capital Installed Annual Cost of Source Proposed Height Upstream Cost Capacity Energy Energy of Site Type Ft. Regulation $. million (MW) Gwh $/1000 k\'/h Data Gold Creek2 . Fill 190 Yes 900 260 1 '140 37 USBR 1953 Olson (Susitna I I) Concrete '160 Yes 600 200 915 31 USBR 1953 KAISER 1974 COE 1975 Devil Canyon Concrete 675 No 830 250 1,420 27 This Study Yes 1,000 600 2,9BO n II High Devil Canyon II (Susitna I) fill B55 No 1,SOO BOO 3,540 21 11 Devil Creek 2 Fill Approx No B50 \~atana Fill B80 No 1 ,B60 BOO 3,250 28 II Susitna III fill 670 f\b 1,390 350 .. 1 '580 41 II Vee fill 610 No '1 '060 400 1,37G 37 II Maclaren 2 Fill 185 No 530 4 55 1BO 124 II Denali Fill 230 No 4B0 4 60 245 B1 II Butte Creek2 Fill Approx No 40 1.303 USBR 1953 150 Tyone 2 fill Approx No 6 22 3 USBR 1953 60 Notes: (1) Includes AFDC, Insurance, Amortization, and Operation & Maintenance Costs. (2) f\b delailed engineering or energy studies undet~taken as part of this study. (3) These are approximate estimates and serve only to represent the potential .of these two damsites in perspective. (4) Include estimated costs of power generation facility. --- ---- -.. ~ ... - - ---._ ---- DAM Site Gold Creek Olson (Susitna II) Type Fill Conceete Devil Canyon Fill Concrete Arch Concrete Gravity High Devil Canyon Fill (Susitna I) De~il Creek Fill \~at ana Fill Susitna Ill Fitl Vee Fill Maclaren Fill Denali Fill Notes: TABLE B.2: COST COMPAR!SONS A C R E 5 1980 Capital Installed Capital Cost Capacity -MW $ million 60r) BOO BOO 350 400 55 6f) 1,000 1,500 1,B60 1,390 1,060 530 4BO Cost Estimate2 (1900 $) tnstalled Capacity -M\~ 776 776 700 792 445 None o 1 A t R 5 Capita[ Cost $million B90 550 630 910 1,630 770 500 (1) Dependable Capacity (2) Excluding Anchorage/Fairbanks transmission inttH·tie, but inc.luding local access andctJ.•ansmission. Source and Date of Data USBR 196B COE 1975 em: 1975 CO£ 1970 COE 1975 CO£ 197B KAISER 1974 mE 1975 CU£ 1975 ---- TABL£ 8. 3: DO.M CREST AND FULL SUPPLY LEVELS Staged run Dam Average Dam Supply Crest Tall water Site Construction Level -Ft. Level -Ft. Level -ft. Gold Creek No 870 880 680 Olson No 1,020 1,030 810 Portage Creek No 1,020 1,030 870 Devil Canyon - intermediate height No 1,250 1,270 890 Devil Canyon - full height No 1,450 1,470 890 High Devil Canyon No 1,610 1,630 1,030 No 1,750 1,775 1,030 Watana Yes 2,000 2,060 1,465 Stage 2 2,200 2,225 1,465 Susitna III No 2,340 2,;>60 1,810 Vee. No 2,330 2,350 1,925 Maclaren No 2,395 2,405 2,300 Denali No 2,540 2,555 2,405 Notes: (1) To foundation level. Dam~ Height 1 ft. 29iJ 310 250 465 675 710 855 680 880 670 610 18.5 230 I I I I I I I I I I I I f I I I I ' I, - - - - --·~· -· -- - - -·-" ----- Devil Canyon 1470 ft Crest Item 600 MW 1) Lands, Damages & Reservoirs 26 2) Diversion Works 50 3) Hain Dam 166 4) Auxiliary Dam 0 5) Power System 195 6) Spillway System 130 7) Roads and Bridges 45 8) Transmission Line 10 9) C~np Facilities and Support 97 10) f.1iscellaneous 1 8 11) Mobilization and Preparation Subtotal Contingency (20%) Engineering and Owner's Administration (12%) TOTAL Notes: 30 757 152 91 ·woo TABLE 8.4: CAPITAL COST ESTIMATE SUMMARIES SUSITNA BASIN DAM SCHE~£5 COST IN $MILLION 1980 High Devil Canyon '1775 ft Crest 800 M\~ 11 48 432 0 232 68 10 140 8 47 1137 227 136 1500 ~latana 2225 ft Crest BOO M\~ 71 536 0 244 16~ 96 26 160 8 57 1lt09 282 169 1860 Susitna I tl 2360 ft Crest 330 MW 13 88 398 0 140 121 70 40 130 8 45 1053 211 126 1390 ('1) Includes recreational facilities, buildings and grounds and permanent operating equipment. Vee 2350 ft Crest 400 M~.' 22 37 183 40 175 74 80 49 100 8 35 803 161 96 1060 Maclaren 2405 ft Crest No power 25 t·t8 106 0 0 .0 57 0 - 53 5 15 379 76 45 500 00ih1sli Z~SO ft Crest ~;·power ... -- )8 112 100 0 0 0 14 0 so 5 14 3J3 67 40 440 TABLE 8.5: RESULTS OF SCREENING MODEL / Total .Demand 0 timal Solution First Subo timal Solution Second Subo Jtimal Soul tion; Max. otal ax. lnst. otal Max. Inst. t:~tal Cap .. Energy Site " Water Cost Site \1ater Cap. Cost Site Wate1: Cap. i'r..nst Run M\~ GWh Names level $ million Names level MW $ million Names level MW $. rmillion 1 400 1750 High 1580 400 885 Devil .1450 400 970 Watana '1950 400 '9BO Devil Canyon Canyon 2 800 3500 High 1750 800 1500 \1atana 1900 450 1130 \~a tan a 2200 800 trS60 Devit Canyon Devil Canyon 1250 350 710 TOTAL 800 1840 3 1200 5250 Watana 2110 700 '1690 High 1750 800 1500 High '1750 820 nsno Devil Devil Canyon Canyon Devil .1350 500 800 Vee 2350 400 1060 Susitna 2300 380 1:;z6o Canyon III TOTAL 1200 2490 TOTAL 1200 2560 TOTAL 1200 ~160 4 1400 6150 Watana 2150 740 1770 N 0 S 0 L U T I 0 N N 0 S 0 l U T. 1 0 N Devil 1450 660 '1000 Canyon -. -----... - ---·--·~-tr•---- I I I I I I I ·~ I I I I I I I I TABLE 8.6: INFORMATION ON THE DEVIL CANYON DAM AND TUNNEL SCHEMES Devil Canyon Dam Tunnel Scheme Item Reservoir Area (Acres) River Miles Flooded Tunnel Length (Miles) Tunnel V3lume (1000 Yd ) Compensating Flow Release from Watana (cfs) Downstream2 Reservoir Volume (1000 Acre-feet) Downstream D~ Height (feet) Typical Daily Range of Discharge From Devil Canyon Powerhouse (cfs) Approximate Naximum Daily Fluctuations in Downstream Reservoir (feet) Notes: 7,500 31.6 0 0 0 1,100 625 6,000 to 13,000 2 320 2.0 27 11,976 1,000 9.5 75 4,000 to 14,000 15 0 0 29 12,863 1,000 4,000 to 14,000 ~ 1,000 cfs compensating flow release from there-regulation dam. 3 .Downstream from Watana. Estimated, above existing rock elevation. --r- 3,900 15.8 13.5 3,732 soo 1 350 245 8,300 to 8,900 4 0 0 29 5, 131 1,000 }~9:00 tttJ 4ltr~no () TABLE 8. 7: DEVIL CANYON TUNN£.L SCHEMES . COSTS, POWER OUTPUT AND AVERAGE ANNUAL ENERGY 1 Tunnel Scheme Installed Inctease 1 Devil Canyon Increase in Caeacitl (HW) in Average Annual Average Total Project Watana Devil Canyon Installed Capacity Energy Annual Energy Costs Stage Tunnel (NW) (Gwh) (Gwh) $ Million STAGE "1 : \vatana Darn BOO STAGE 2: Tunnel: -Scheme 1 800 550 550 2,050 2,050 '1980 -Scheme 22 70 1,150 420 4,750 1,900 2320 -Scheme 3 850 330 380 2,240 2,180 1220 -Scheme 4 800 365 365 2,490 890 '1490 Notes: Q (1) Increase over single Watana, 800 M\1 development 3,250 Gwh/yr (2) Includes pm'ler and energy produced at re-regulation dam (3) Energy cost is based on an economic analysis (i.e. using 3 percent interest rate) 0 -----~--------•. ... 33 Cosl::: of AdditUionfl Enrurgy (m.iillls/kWh) ._,.,_ ... 4Z;'.,.t) 5~ ... 9 Zf.4..9 7~ .. 6 --- I I I I I I I I I I I I I I I I I I ; TABLE 8.8: CAPITAL COST ESTIMATE SUMMARIES TUNNEL SCHEMES COSTS IN $t4ILL ION 1980 Two 30 ft Item dia tunnels land and damages, reservoir clearing Diversion works Re-regulation dam Power system (a) Main tunnels (b) Intake, powerhouse, tailrace and switchyard Secondary power station Spillway system Roads and bridges Transmission lines Camp facilities and support Miscellaneous* Mobilization and preparation TOTAL CONSTRUCTION COST Contingencies (20%) Enoineering, and Owner's Administration TOTAL PROJECT COST 557 123 14 35 102 680 21 42 42 15 131 8 47 1,137 227 136 1,500 One 40 ft dia tunnel 14 3S 102 576 453 123 21 42 42 15 '117 8 47 1,015 203 1.22 1,340 ,. TABLE 8.9: SUSlTNA DEVELOPMENT PLANS Cumulative Staqe/lncremental Data System Data Annual Maximum Energy Capital Cost Earliest Reservoir Seasonal Production Plant $ Nillions On-line Full Supply Draw-firm Avg. Factor Plan Stage Construction (1980 values) 1 Date Level -ft. dmm-ft GWH G\~H. 1)1 10 1.1 1 Watana 2225 ft BOOMW 1860 1993 2200 150 2670 3250 46- 2 Devil Canyon 1470 ft 600 M~l 1000 '1996 "1450 100 ssoo 6230 S'l TOTAL SYSTEM 1400 MW 2860 1.2 \~atana 2060 ft 400 MW 1570 1992 2000 100 1710 2110 60 2 \1atana raise to 2225 ft 360 1995 2200 150 2670 2990 85 3 Watana add 400 MH capacity 130 2 1995 2200 150 2670 3250 46 4 Devil Canyon 1470 ft 600 MW 1000 1996 '1450 100 5500 6230 51 TOTAL SYSTEI-1 1400 H\1 3060 1.3 1 Watana 2225 ft 400 MW 1740 "1993 2200 150 2670 2990 85 2 Watana add 400 MW capacity '150 1993 2200 150 2670 3250 46 3 .Devil Canyon 1470 ft 600 MW 1000 1996 1450 100 5500 6230 51 TOTAL SYSTEM 1400 MW 2890 -----------,., •. -. -----.. -....• --- -------~~~~~~-~--~ '"' <· ------------.. ------ TABLE 8.9 (Continued) Cumulative Stage/Incremental Data System Data Annual Maximum Energy Cap· .al Cost Earliest Reservoir Seasonal Production Plant $ Millions On-line. Full Supply Draw-Firm Avg. Factor Plan Stage Construction (1980 values) 1 GWH GWH Ol Date Level -ft. down-ft. #Q 2.1 High Devil Canyon 1775 ft 800 MW 1500 1994 3 1750 150 2460 3400 49 2 Vee 2350 ft 400 MW 1060 1997 2330 '150 3870 4910 . 47 TOTAL SYSTEM 1200 HW 2560 2.2 1 Hlgh Devil Canyon 1630 ft 400 M\'1 1140 1993 3 1610 100 1770 2020 58 2 High Devil Canyon add 400 H\'1 Capacity raise dam to 1775 ft 500 '1~96 1750 150 2460 .3400 49 3 Vee 2350 ft 400 MW 1060 ·t997 2330 150 3870 4910 47 TOTAL SYSTE~1 1200 MW 2700 2.3 1 High Devil Canyon 1775 ft.400 MW 1390 1994 3 1750 150 2400 2760 79 2 High Devil Canyon add 400 MW capacity 140 1994 1750 150 2460 3400 49 3 Vee 2350 ft 400 MW 1060 1997 2330 150 3870 4910 47 TOTAL SYSTEM 1200 MW 2590 ~· 3.1 1 Watana 2225 ft 800 M\'1 1860 1993 2200 '150 2670 3250 46 2 \'/atana add 50 H\'1 tunnel 330 M~/ 1500 '1995 1475 4 4890 5430 53 TOTAL SYSTEM 1'180 M\'1 3360 TABLE 8.9 (Continued) Cumulative Stage/Incremental Data System Data Annual Haximum Energy Capital Cost Earliest Rese-cvoir Seasonal Production Plant $ Millions On-line Tull Supply Draw-tirm Avg. Factor 1 Level .:. Plan Stage Construction (1980 values) Date ft. down-ft. GWH GWH Q/ 10 3.2 1 Watana 2225 ft llOO M\~ 1740 1993 2200 150 2670 2990 85 2 Watana add 400 MW capacity ISO 1994 2200 150 2670 3250 46 3 Tunnel :no ~1W add 50 MW to Watana 1500 1995 '1475 4 4890 5430 53 3390 4.1 1 Watana 2225 ft 400 MW 1740 19953 2200 '150 2670 2990 85 2 Watana add 400 M~l capacity 150 1996 22.00 150 2670 3250 46 3 High Devil Canyon 1470 ft 400 MW 860 1998 1450 '100 4520 5280 50 4 Portage Creek 1030 ft '150 t-1W 650 2000 1020 50 5110 6000 51 TOTAl SYSTEM 1350 M\~ 3400 NOTES: (1) Allowing for a 3 year overlap construction pel'iod between major dams. (2) Plan 1.2 Stage 3 is less expensive than Plan 1.3 Stage 2 due to lower mobilization costs. (3) Assumes FEHC license can be filed by June 1984, i.e., 2 years later than fot the \~atana/Devil Canyon Plan L G --··--· .. .. ---·---·-----,·-- I I I I I I I I I I I I I I •• I I I I TABLE 8.10: ENERGY SIMULATION SENSITIVITY Reservoir Maximum Installed full Supply Reservoir Annual Capacity Level Orawdown Development M\'1 f"eet Feet Firm (%) Watana 2225 feet 800 .2200 100 2510 (89) 800 .2200 150 2670 (94) 800 2200 175 2770 (98) 800 2200 Unlimited 2830 (-100) Notes: (1) Second lowest energy generated during simulation period. Energi:-Gwh Plant Factor Average 0~) % 3210 (101) 45.8 3250 (103) 46.4 3200 ( 101) 45.7 3170 (100) 45.2 TABLE 8.11: SUSITNA ENVIRONMENTAL DEVELOPMENT PLANS umulative Stage/Incremental Data System Data Annual Maximum Energy Capital Cost Earliest Reservoir Seasonal Pt>oduction Plant $ Millions On-line Full Supply Dt>aw-Firm Avg. Factor (1980 values) 1 Plan Stage Construction Date Level -ft. down-ft G\m G\1H. 01 10 E1.1 Watana 2225 ft BOO MW and He-Regulation Dam "1960 1993 2200 150 2670 3250 46 2 Devil Canyon 1470 ft 400 M\1 900 1996 '1450 100 S520 6070 58 TOTAL SYSTEM 1200 HW Wbrf E1.2 1 Watana 2060 ft 400 HW 1570 1992 2000 100 17'10 2110 60 2 Watana raise to 2225 ft 360 1995 2200 ISO 2670 2990 85 3 Watana add 400 MW capacity and He-Regulation Dam 230 2 1995 2200 150 2670 3250 46 4 Devil Canyon 1470 ft 400 HW 900 '1996 1450 100 5520 6070 58 TOTAl SYSTEM '1200 M\'1 3060 El.3 1 Watana 2225 ft 400 MW 1740 1993 2200 150 2670 2990 85 2 ~/atana add 400 MW capacity and He-Regulation Dam 250 1993 2200 ISO 2670 3250 46 3 Devil Canyon 1470 ft 400 MW 900 "1996 1450 100 5520 6070 58 TOTAL SYSTEM 1200 MW 2890 ------------------- ----------·---------- TABLE 8. '11 (Continued) Cumulative Stage/Incremental Data S~stem Data Annual Nax.imum Energy Capital Cost Earliest Reservoir . Seasonal Production Plant $ Millions On-line full Supply Draw-firm Avg. factor (1980 values) Date 1 Level -ft. down-ft. GWH .G\~H 01 Plan Stage Construction 10 E1.4 .1 Watana 2225 ft 400 MW 1740 '1993 2200 '150 2670 2990 85 2 Devil Canyon ·J470 ft 400 M~l 900 1996 1450 100 5190 5670 81 TOTAl SYSTt~i 800 NW 2640 E2.l 1 High Devil Canyon 1775 ft 800 MW and Re-Regulation Dam 1600 1994 3 1750 150 2460 3/iOO 49 2 Vee 2350ft 400 MW 1060 1997 2330 150 3870 49'10 47 TOTAL SYSTEH 1200 M\~ 2660 E2.2 High Devil Canyon 1630 ft 400 HI/ 1140 1993 3 1610 100 1770 2020 58 2 High Devil Canyon raise dam to 1775 ft add 400 M\~ and He-Regulation Dam 600 1996 ·n5o 150 2460 3400 ·49 3 Vee 2350 ft 400 MW '1060 1997 2330 150 3870 4910 47 TOTAL SYSTEM 1200 MW 2800 E2.3 1 Hig~ Devil Canyon 1775 ft 400 MW 1390 1994 3 1750 150 2400 2760 79 2 High Devil Canyon add 400 NW capacity and He-Regulation Dam 240 1995 1750 150 2460 3400 49 3 Vee 2350 ft *400 MW 1060 1997 .2330 150 3870 4910 47 TO!AL SVSTEH 1200 1-1~/ 2690 TABLE 8.11 (Continued) .., umu a J.ve Stage/Incremental Data S}::stem Data Annual ~ ~1aximum Energy Capital Cost Earliest Reservoir Seasonal Production Plant $ Hillions On-line Full SUj!lply Ora\'/-Firm Avg, Factor Plan Construction (1980 values) Date 1 Level -ft. G\~H GWH Stage down-ft. 01 i1l £2.4 1 High Devil Canyon 17S5 ft 400 HW "1390 1994 3 1750 150 2400 2760 79 2 High Devi I CHnyon add 400 HW capacity and Portage Creek Dam 150 ft 790 1995 '1750 '150 3170 4080 49 Vee 2350 ft 400 HW 1060 1997 2330 150 4lt30 5540 '•7 TOTAl SYST£11 "3"241:f £3.2 1 Watana 222 5 ft 400 MW '1740 1993 2200 150 2670 2990 85 2 Watana add 400 NW capacity and He-Regulation Dam 250 1994 2200 ISO 2670 3250 46 3 Watana add 50 M~l Tunnel Scheme 330 N~l "1500 1995 1475 4 4890 5430 53 TOTAL SYSTEM 1180 MW 1490 £4.1 l Watana 2225 ft 400 NW 1740 1995 3 2200 150 2670 2990 85 2 \~ar ana add 400M~·I capacity and He-Regulation Dam 250 1996 2200 '150 2t:~: .. D 3250 46 3 High Devil Ca~1 on 14 70 ft ~;utJ H\~ 860 1998 1450 100 4520 5280 50 4 ., ...,L._aye Creek 1030 ft 150 MW 650 2000 '1020 50 5110 6000 51 T.OTAL SYSTEt4 1350 MW )SQ(f r. NOTES: (-1) Allm'ling for a 3 year overlap construction period between major dams. (2) Plan 1.2 Stage 3 is less expensive lhan Plan 1.3 Stage 2 due to lower mobiLization costs. {3) Assumes FERC license can be filed by June 1984 1 i.e., 2 years later than for the \~atana/Devil Canyon Plan 1. --------- - - - ---- -.. --- I I I I I I I I I I I I I I I I I I .I . ~.~ .. -.-.. ,.... ....... TABLE 8.12: ANNUAL fiXED CARRYING CHARGES Project Type Thermal -Gas Turbine (Oil Fired) -Diesel, Gas Turbine (Gas fired) and Large Steam Turbine -Small Steam Turbine Hydropower Economic Life -Years 20 30 35 50 Economic Parameters Total Cost of Annual Money .~ortization Insurance f'ixed Cost % % % % 3.00 3~72 0.25 6.97 3.00 2.10 0 .. 25 5.35 3.00 1.65 0.25 4.90 3.00 0.89 0.10 3.99 TABLE 8.13: RESULTS Of ECONOMIC ANALYSES OF SUSITNA PLANS-HEDIUH LOAD FORECAST SusiEna lJeveioemenE Pian Inc. Installed Capiaaity (Mw;-Ey Total System 1otat System Online Oates Categor~ in 2010 Installed Present Remarks ~e~~ining to Plan Stages OGP5 Run Thermal H~dro Capacity In Worth Cos~ the Swdtnm 13asin No. z 3 4 I d. No. Coal Gas Oii Otfier !lusitna 20'10-MW $ Million Develoernenl:! Plan £1.1 1993 2000 LX£7 300 l~26 0 144 1200 2070 5050 £1.2 1992 1995 1997 2002 L5Y9 200 501 0 144 1200 2045 6030 £1.3 1993 1996 2000 L8J9 300 426 0 144 1200 2070 5850 '1993 1996 l7W7 500 651 0 '144 800 2095 6960 Stage 3, Oe:w·il Canyon Dam not constrtanted 1998 2001 2005 LAD7 400 276 30 144 1.200 2050 6070 Delayed imJii::tementat ion schedule E1.4 1993 2000 LCK5 200 726 50 144 000 1920 S090 Total cbveJ2:.oprnent limited to 800 NW· Modified £2.1 1994 2000 LB2S 400 651 60 144 800 205$ 6620 High Devil l'tanyon limited to 400 NW £2.31 '}993 '1996 2000 L601 300 651 20 144 1200 2315 6370 1993 1996 L£07 500 65~ 3G 144 800 . 2125 6720 Stage 3 , Ve-ft!l Dan, not constructectl Modified £.2.3 1993 1996 2000 LEB3 300 726 220 144 1300 2690 6210 Vee dam re~~~ced by Chakachamnat .dam 3.1 1993 1996 ~000 L607 200 651 30 144 1180 2205 6530 Special 3.1 1993 '1996 2000 l615 200 65'1 30 144 1180 2205 6230 Capital co.~!t uf tunnel reduced by ~~ percent E4.·J 1995 1996 1998 LTZS 200 576 30 144 1200 21.50 6050 Stage 4 no.t constructed NOTES: (1) Adjusted to incorporate cost of re-regulation dam - --c-- - - - - - - - -,-- --- - -------------------TABLE 8.14: RESULTS OF ECONOMIC ANALYSES OF SUSI1NA PLANS -LOW AND HIGH LOAD fORECAST Susitna De\'elopment Plan Inc .. Online· Dates Plan Stages No. • 1 2 3 4 VERY Lml FORECAST 1 £1.4 1997 2005 LOW LOAD FORECAST t1.3 £1.4 £2.1 £.2.3 Special 1993 1996 2000 1993 2002 1993 1993 2002 1993 1993 1996 2000 3.1 1993 1996 2000 3.2 1993 2002 HIGH LOAD FORECAST E1.J 1993 1996 2fl00 Modified E1.3 1993 1996 2000 2005 £2.3 1993 1996 2000 Modified EZ.3 1993 1996 2000 2003 ·NOTE: ·oGP5 Run Id. No. L7B7 LC07 LBK7 LG09 LBU1 l6.13 L609 LA73 LBV7 LBVJ LBY1 (1) Incorporating load management and conservation Insta{[ed Capacity (MW) by Category in 2010 Thermal Hydro Coal Gas Oil Other Susitna I) 651 n 351 200 501 100 426 400 501 fl 576 0 576 1000 951 BOO 651 1300 951 1000 .876 50 40 BO 30 0 20 20 60 90 10 144 144 144 144 144 144 144 144 144 144 144 eon BOO 400 BOO 400 780 780 1200 1700 1200 1700 Total System Installed Capacity In 2010-HW 1645 1335 1325 1500 1445 1520 1520 3295 3.355 3685 3730 Total Systen1 Pt·esent \'lorth Cost $ Million 3650 435r) 4940 IJ560 4850 4730 5000 10680 10050 11720 11040 Remarks Pe rtai~ng to the Susitna BfJ:u;.jn De\eloprnent Pt<lin Lo\'1 energy dem~nd does not warrant plan ~acities Stage 2, Ded;.l1 ~tanyon Dam, not constructel'.ot~ High De\'il C'an~von limited to 400 MW " Stage 2, Vee Ol:alr!, not constructed Low energy denmmd does not warrant plan ~nacities Capital cost QJf tunnel reduced by 50' f~rcent Stage 2, 4fl0 M!\ti addition to Watana, nut; constructed Chakachamna h~~tuelectric gene rating st~t.ion ( 480 M\q) brought on lit\\~ as a fourth stage Chakachamna hydt'O~lectric generating station (4BO M\~) brought on Une as a fourth stage TABLE 8.15; RESULTS OF ECONOMIC SENSITIVITY ANALYSES fOR GENERATION SCENARIO- INCORPORATING SUSITNA BASIN DEVELOPMENT PLAN £1.3--MEDIUM fORECAST Descri~tion Parameter OGP5 Run Parameter ~ariea Values Id. No. Interest Rate 5% -LF85 9% LF87 fuel Cost ($ million Btu, natural gas/coal/oil) 1.60/0.92/3.20 LS33 fuel Cost Escalation (%, 0/0/0 natural gas/coal/oil) L557 3.98/0/3.58 L563 Economic Life of Thermal Plants (year, natural gas/coal/oil) 45/45/30 L585 Thermal Plant Capital Cost ($/kW, natural gas/ 350/2135/778 coal/oil) LED7 \~atan2/Devil Canyon Capital Cost ($ million, \~atana/ Devil Canyon) 1990/11'10 L5G1 2976/1350 LD75 Probabilistic Load Forecast L8TS NOTES: (1) Alaskan cost adjustment factor reduced from 1.8 to 1.4 (2) Excluding AFDC o a o a Installed Capacity (M\~) by System System Installed Present Categor:i in 2010 Capacity Worth Tliermai Ayaro In 2010 Cost Co a I Gas lJii DEFier Susitna MW $ Million 300 426 0 144 1200 2070 4230 ?JOO 426 0 144 1200 2070 2690 100 516 20 144 1200 2040 5260 0 651 30 144 1200 2025 4360 300 426 0 1l~4 1200 2070 5590 45 367 233 144 1200 1909 6100 300 426 0 144 1200 2070 5740 300 426 0 144 1200 2070 .6210 300 426 0 1ll4 1200 2070 6810 200 1476 140 144 1200 3160 6290 Remarks 20% fuel caJst reduction Zero escalalt'i-tm Zero coal ~t escalation Economic ~~~s increased by 50% Coal capit~'ll cost reduced by 22~~ Capital co~t for Devil Canyon Dam-increased by 23% Capital CO;St for both dams increased ~~· '50% - - - - - - - - -··-- - - - - - - - - I I I I I I I I I I I I I I I I I ............ -· ' I . I . TABLE 8.16: ECONONIC BACKUP DATA FOR EVALUATION OF PLJl.NS Parcimeter Capital Investment Fuel Operation and Maintenance TOTAL: Total Present Worth Cost for 1981 -2040 Period $ Million (% Total) Generation Plan Generation Plan Generation Plan With High Devil With Wat:ana -With Watana - Canyon -.Vee Devil Canyon Dam Tunnel 2800 (44) 2740 (47) 3170 (49) 3220 (50) 2780 (47) 3020 (46) .350 (6) 330 (6) 340 (5) 6370 (100) 5850 (100) 6530 (100) " fJ.l Thermal Generation Plans ), 2520 {)1) 5240 (64) "' 310 (5) 8130 (100) - TABLE 8.17: ECONOMIC EVALUATION Of DEVIL CANYON DAM AND TUNNEL SCHEMES AND ~IATANA/DEVIL CANYON AND HIGH DEVIL CANYON/VEt rm .. ANS ECONotHC EVALUATION: -Base Case SENSITIVITY ANALYSES: -Load Growth -Capitpl Cost Estimate -Period of Economic Analysis -Discount Rate -Fuel Cost -Fuel Cost Escalation -Economic Thermal Plant Life --- Low High Period shortened to (1980 -2010) 5~~ 9% (interpolated) 9~~ 80% basic fuel cost 0% fuel escalation 0%. coal escalation smb extension mb extension -·-- Present wotth of Net Benefit ($ mill ion) of total generation system costs for the: Devil Canyon Dam over the Tunnel Scheme 680 650 N .. A. Higher uncertainty assoc- iated with tunnel scheme. 230 Watana/Devil Canyon Dams over the High Devil Canyon/Vee Dams 520 210 1040 Higher uncertainty associated with H.D.C./Vee plan. 160 As both the capital and fuel costs associated with the tunnel scheme and H.D.C./Vee Plan are higher than for \~atana/Oevil Canyon plan any changes to these parameters cannot reduce the Devil Canyon or Watana/Oevil Canyon net benefit to below zero. ---·--- -- Reman1k:s Economic ranking~ :Devil Canyon dam scheme is supe.Tior to Tunnel scheme. Watana/O~.vil Canyon dam plan is superior tm the High Devil Can on dam/VJP.e dam plan. The net bonefit u.f' the Watana/Dev i l CanyQt~ plan remains positive for the I~mnqe of load forecasts considet:ftld.. No. change in ranking. Higher cost uncerf:atj hties associ- ated with higher CQ'I~t schemes/plans. Co~ uncertainty therefore does not -Slffect economic ranking. Shorter period of ~~aluation decreases economic-·differences. Ranking remains u~hanged. Ranking remains un~)anged. ---- I I I I I I I I I I I I I •• II I I fnvitonmental Attribute Ecological: -Downstream fisheries and Wildli·fe Resident Fisheries: Wildlife: Cultural: land Use: TABLE 8.18: ENVIRON~tENTAL EVALUATION Of DEVIL CANYON DAt-i AND TUNNEL SCHEME Identification Concerns of difference Appraisal JudQ\=?r~Jent SCheme JUdged to have the least·. potential impact 1unnel bC Effects resulting from t::hanges in water quantity and quality. Loss of resident fisheries habitat. Loss of wildlife habitat. Inundation of archeological sites. Inundation of Devil Canyon. No significant differ- ence between schemes regarding effects down- stream of Devil Canyon. Difference in reach between Devil Canyon dam and tunnel re- regulation dam. Minimal differences between schemes. Minimal differences between schemes. Potential differences between schemes. Significant difference · between schemes • \~ith the tunnel scheme con- trolled flows between regula- tion dam and downstream power- house offers potential for anadromous fisheries enhance- ment in this 11 mile reach of the river. Devil Canyon dam would inundate 27 miles of the Susitna River and approximately 2 miles of Devil Creek. The tunnel scheme would inundate 16 miles of the SUsitna River .. The most sensitive wildlife ha- bitat in this reach is upstream of the tunnel re-regulation dam where there is no significant difference between the schemes. The Devil Canyon dam scheme in addition inundates the river valley between the two dam sites resulting in a moderate increase in impacts to wildlife. Due to the larger area inun- dated the probability of inun- dating archeological sites is increased. · The Devil Canyon is considered a unique resource, 80 percent of which would he inundated by the Devil canyon dam scheme. This would result in a loss of both an aesthetic value plus the potential for ¥!bite water recreation. Not a factor in evaluation of scheme. , If fisheries enhancement oppor- . t.unity can be realized the tun- nel scheme offers a positive mitigation measure not available with the Devil Canyon dam scheme. This opportunity is considered moderate and favors the tunnel scheme. However 1 there are no current plans for such enhancement and feasibil- ity is uncertain. Potential value is therefore not signi- ficant relative to additional cost of tunnel. Loss of habitat with dam scheme is less than 5% of total for Susitna main stem. This reach of river is therefore not considered to be highly significant for resident fisheries and thus the difference between the schemes is minor and favors the tunnel scheme. Moderate wildlife populations of moose, black bear, weasel, fox,. wolverine, other small mammals and songbirds and some riparian cliff habitat for ravens and rap tors, in 11 miles of river, would be lost with the dam scheme. Thus, the difference in loss of wildlife habitat is considered moderate and favors the tunnel scheme. Significant archeological sites, if identifi.ed, can proba- bly be excavated. Additional costs could range from seve_J:'al . hundreds to hundreds of thousands of dollars, but are. still consider- ably less than the additional cost of the tunnel scheme. This concern is not considered a factor in scheme evaluation. The aesthetic and to some extent the recreational lasses associ- ated with the developrr:ent of the Oev il Canyon dam is the main aspect favoring the tunnel scheme. However, current recreational uses of Devil Canyon are low due to limited access.. future possibilites include major recreational develop- ro~nt with construction of·testau- rants, marinas, etc. Under such conditions, neither scheme would be more favorable. X X X :o:V:E:RA=·=LL==E=V=A=L=U=A=T=I=O=N~:~T~h:e~t~u~n:n:e~l_:sc~h~e:m:e~h~a=s~o:v:e:r:a~ll~a~l:o:w:e:r_:i:m:p:a:ct~o=n~.~t:h=e~.~e~nv~~=·r~o=n~m=e~n=t~·--------------~------~~----~~------------------------~~-------------------------- --- Social Aspect - Potential non-renewable resource displacement Impact on state economy Impact on local economy Seismic exposure Overall Evaluation --.... --------- --· ~- TABLE 8.19: SOCIAL -EVALUATION OF SUSITNA BASIN DEVELOP~1ENT SCHEMES/PLANS Parameter Million tons Beluga coal over 50 years Risk of major structural failure Potential impact of failure on human life. Tunnel Scheme Devil Canyon Dam Scheme High Devil Canyon/ Vee Plan Watana/oevi 1 . Canyon Plan Remarks 80 110 170 210 Devil Canyon dam scheme potential higher than tunnel scheme. Watana/ Devil Canyon plan higher than High Devil Canyon/ Vee plan. All projects would have similar impacts on the state and l0cal economy. All projects designed to similar levels of safety. Any dam f::Uures \'/auld effect the same downstream population. Essentially no difference between plans/schemes. 1. Devil Canyon dam superior to tunnel. 2. ~Jatana/Devil Canyon superior to High Devil Canyon/Vee plan. ·- TABLE S.20: ENERGY CONTRIBUTION EVALUATION Of THE DEVIL CANYON DAH AND TUNNEL SCHEHES Parameter Total Energy Production Capab~liEy Annual Average Energy GWH firm Annual Energy GWH % Basin Pqtential Developed Enerfy Potential Not Deve oped G\m Notes: Dam 2850 2590 43 60 Tunnel 2240 2050 32 380 Remarks Devil Canyon dam annually develops 610 G~IH and 540 GWH move average and firm energy respectively than the Tunnel scheme. Devil Canyon schemes develops =more of the basin potent~al. As currently envisaged, the Devil Canyon dam does not develop 15 ft gross head between the ~latana site and the Devil Can~n reservsoir. The tunnel scheme incorporates addi- tional friction losses in tunnels. Also the compen- sation flow released from re-regulation dam is not used in conjunction with head between re-regulation dam and Devil Canyon. · ( 1) Based on annual average energy. Full potential based on USBR four dam scheme. I I I I I I I I I I I I I 'It~· ... I I I I I I -~">;-'""'"''"" ,..; ,.. '. I I •• I I I I I I I I I I I I I I I ·I TABLE 8.21: OVERALL EVALUATION OF TUNNEL SCHEME AND DEVIL CANYON DM4 SCHEME ATTRIBUTE Economic Energy Contribution Environmental Social Overall Evaluation SUPERIOR PLAN Devil Canyon Dam Devil Canyon Dam Tunnel Devil Canyon Dam (t~arginal) Devil Canyon dam scheme is superior Tradeoffs made: Economic advantage of dam scheme is judged to outweigh the reduced environmental impact associated with the tunnel scheme. I I I I I I I I I I I I I I I I I i I • .. _. ',_.,~------ TABLE 8 .. 22: ENVIRONMENTAL £VAlUATION OF WATANA/DEVIt.CANYON AND HIGH .. DE:V!l CANYON/VEE DEVt:lOPMENT PLANS ------·----------·--------~---------------------~'------~------------------------------~--~--·------p-------------------------------------~--------- Environmental Attribute Er.:olorical: 1) ~sheries 2) Wildlife .a) Moose b) Caribou c) rurbearer~ d) Birds and Bears Cultural: Plan judged to have the least.Votential im7act ___________ .-;P.-=l-=a;;.;n_C,;;;.o;;,;m~p:;;.;a::;,;r:.::i:.::s:.::o;,;.;n;;.._.. __________________ .:..J,AJlE,.t'aisal· Judgement ·--------·....:H~D:;.;C;;.:./....:-____ _,;,...;.W;.::.· .;.b..;;;C __ No significant difference in effects on downstream anadromous fisheries. HDC/V would inundate appl:'oximately 95 miles of the Susitna River and 28 miles of tributary streams, in-. eluding the Tyone River. W/DC would inundate approximately 84 miles of the Susitna River and 24 miles of tributary streams, includi~g Watana Creek. HDC/V would inundate 123 miles of critical winter river bottom habitat. W/DC would inundate 108 miles of this riv~r bottom habitat. HDC/V would inundate a large area upstream of Vee utilized by three sub-populations of moose that range in the northe~st section of the basin. W/DC would inundate the Watana Creek area utilizt~d by moose. The condition of this nub-population of moose and the quality of the habitat they are using appears to be decrAasing. The increased length of river flooded, especially up- stream from the Vee dam site, would result in the HDC/V plan creating a greater potentia.! division of the Nelchina herd's range. In addition, an increase in range would be directly inundated by the Vee res- ervoir. The at~a flooded by the Vee reservoir is conside['ed important to some .key furbearers, particularly red fox. This ·ar.ea is judged to be more important than the Watana Creek area that would be inundated by the W/DC plan. Forest hahi,t.at, important for birds and black bP-ars, exist along the valley slopes. The loss of this habi- tat t-~ould be great~r with the W/DC plan. There is a high potential for discovery of archeologi- cal sites in the easterly T.egiol) of the Upper Susitna Basin.. Thfl HDC/V plan has a greater potential of affecting these sites. Fo:i" other reaches of (•the river the difference bet.ween plans is considet"ed minimal. D...Je to the avoidance of the Tyone River, lesser inundation of resident fisheries habitat and m.i signi fie ant difference in the effects on aoadromous fisheries, Um: W/OC plan is judged to have lese impact. IAle t1J the lower potential for direct impact on moose populations within the Susitna, the W/DC plan is judged superior. · t:ue to the potential for a greater impact on the Nelchina caribou he.rd, the HDC/V scheme is considered inferior. Qu,-. to the lesser potential for impact on fur- beart.'l'S the W/DC is judged to be supe.rior. The HDC/V plan is judged superior .• The W/DC plan is judged to have a lower po- tential .effect on archeological sites. X X X X ,, X X ·I· ... i :' j I I I I I I I I I I I I I I I I •• TABLE 8.22 (Continued) Environmental Attribute Ae$thetic/ land Use Plan Comparison With either scheme, the aesthetic quality of both Devil Canyon and Vee Canyon would be impaired. The HDC/V plan would also inundate Tsusema Falls. Due to construction at Vee Dam site and the size.of the Vee Reservoir, the HDC/V plan would inherently create access to more wilderness area than v!Quld the W/DC plan. Appraisal Judgement Both plans impact the valley aesthetics. The difference is consid~;~r•ed minimal"' As it is easier to extend access than to limit it, inherent access requirements were considered detrimental and the W/DC plan is judged superior. The ecologicar sensitivity of the area opened by the HDC/V plan rein- forces this judgement. OVERALL EVALUATION: The W/DC plan is judged to 1-Je superior to the HDC/V plan. (The lower impact on birds and bears associated with HDC/V plan is considered to be outweighed by all the other impacts which favor the W/DC plan.) NOTES: W = Watana Dam DC -:: e-evil Canyon Dam HOC = High Devil Canyon Dam V:::: Vee Dam Abc/ · · . Oc .;;.,__--- X ~~~~~~~=-~~~~~~~~~~~~~~~~-=···-=···~.~~~. ~~~. ~.~~ .. ~.~.~~~~~~~~~~~~~~~~~~~~~-.--. .. ~· ~~=~~ - I I I I I I I I I I I I I I I I I u I I TABLE 8.23; ENERGY CONTRIBUTION EVALUATION OF THE WATANA/DtVll CANYON AND HIGH DEVIL CANYON/VEE PLANS Parameter Total Energy Production Capabih.ty Annual Average Energy GWH Firm Annual Energy G\~H % Basin Potential Developed (1) Eneriy Potential Not Deve oped GWH ~2) Notes: c Watana/ Devil Canyon 6070 5520 91 60 High Devil Canyon/Vee 4910 3870 81 650 Remarks Watana/Devil Canyon plan annually devel- ops 1160 G~/H and 1650 GWH more average and firm energy ra- pectively than the High Devil Canyon/Vee Plan. Watana/Devil Canyon plan develops more of the basin potential As currently con- ceived, the Watana/- Devil Canyon Plan does not develop 15 ft of gross head between the Watana site and the Devil Canyon reservoir. The High Devil Canyon/Vee Plan does not develop 175 ft gross head between Vee site and High Devi1 reservoir. (1) Based on annual average energy. Full potential based on USBR four dam schemes. (2) Includes losses due to unutilized head. . TABlE 8.24: OVERALL EVALUATION OF THE HIGH DEVIL CANYON/VEE AND WATANA/DEV!l CANV~N DAM PLANS ----------------~--~ ATTRIBUTE SUPERIOR PLAN ------------~------------------- Economic Watana/Devil Canyon Energy Contribution Environmental Social Overall Evaluation Watana/Devil Canyon \1atana/Devil Canyon \latana/Devil Canyon (Marginat) Plan with \'latana/Devil Canyon is superior Tradeoffs made: None I I I I I I I I I I I I I I I I I I I - - - - - - - - ---- - ------ - - - TABLE 8.25: RESULTS Of ECONOMIC ANALYSES fOR GENERATION SCENARIO INCORPORATING THERMAL DEVELOPMENT PLAN -MEDIUM FORECAST total System Tot a)) Installed Capacity (MW) Installed System by Category in 2010 Capacity Present Description Parameter OGPS Run Thermal In 2010 \~orth Cost Parameter Var1eo Value Id. No. Co a I Gas iJii ltydro Total MW $ Million Rematit::s Interest Rate 5% LEA9 900 000 50 '144 1895 5170 9% LE81 900 801 so 144 1895 2610 fuel Cost ($ ~illion Btu, natural gas/coal/oil) 1.60/0.92/3.20 L1K7 800 876 70 144 1890 7070 20% fuel cost reduction fuel Cost Escalation (%, natural gas/coal/oil) 0/0/0 L547 0 1701 10 144 1855 4560 Zero esc a lat ~:on 3.98/0/3.58 L561 1100 726 10 144 '1980 6920 Zero coal co-~t escalation Economi~ Life of Thermal '';<~I Plants (year, natural I gas/coal/oil) 45/45/30 l503 1145 667 51 144 2007 7650 'Economic lift!:€ increased ] sm~ Thermal Plant Capital Cost ($/k\~, natural gas/ 350/2135/778 LAL9 1100 726 10 144 1960 7590 Coal capital: 'bast reduced coal/oil) by 22% c - Parameters LOAD GRO\HH CAPITAL COST ESTIMATE PERIOD OF ECONOMIC ANALYSIS Dl5COUNT HATE fUEL CO$T fUEL COST ESCALATIONS ECONOMIC THERMAL PLANT LifE Notes: TABLE 8.26: ECONOMIC SENSITIVITY OF COHPARISON Of GENERATION PlAN \HTH WATANA/DEVIL CANYON AND THE ALL THERHAL PLAN Present worth of Net Benefit ($ million) of total generation system-costs for the Watana/Devil Canyon plan over the all thermal plan. Sensitivity Analyses Present worth ($ million) Very low Lm-1 Medium High L0\'1 Thermal Cost2 High 3Hydroelectric Cost 1980 -2040 1980 -2010 301 10 5% 8% (interpolated) 9 ot #0 0% escalation for all fuels 0% escalation for coal only 50% extension to all thermal plant life 1280 1570 2280 2840 1850 1320 2200 960 2200 940 0 -80 1810 200 '1330 1800 Remarks The net benefit of the Watana/Devil CanyQf'tl ¥Plan re- mains positive for the range of load forecrusts con-. side.red. System costs relatively : nsensitive. Capi..J:t~l cost estimating uncertainty does not effect ecQll1()lllic ranking. Shorter period of evaluation decreases ecr,momic dif- ferences. Ranking remains unchanged. Below discount rate of 8% the \~atana/Devill ~"Canyon plan is economically superior. Watana/Devil Canyon plan remains economiG'aiil!l.y super- inr for wide range of fuel prices and P.sc~~tion rates. Economic benefit for Watana/Devil Canyon ~~an rela- tively insensitive to extended thermal platill economic life. (1) All parameters, except load growth, tested using medium load forecast. (2) Thermal capital cost decreased by 22%. (3) Estimated Susitna cost increased by sm~. ( 4) All fuel costs reduced by 2m~. Base case costs $/mi Ilion Btu: Coal 1 • 15, Gas 2. 00, Oi 1 4. oo· --- ----,-···· .. -------- ---I I -.J) Social Aspect Potential non~renewable resource displacement Impact on state economy Impact on local economy Seismic exposure Overall Comparison - --.. ---- TABLE 8.27: SOCIAL COMPARISON Of SYSTEM GENERATION PLAN WITH WATANA/OEVIL CANYON AND THE ALL THERMAL PLAN Parameter Million tons of Beluga coal, over 50 years Direct & Indirect employment and in- come. Business investment. Risk o f major structural failure Potential impact of failure on human life. All Thermal Generation Plan Gradually, contin- uously growing impact. Generation Plan with \'latana/Devil Canyon 210 Potentially more dis- rHptive impact on economics. All projects designed to similar levels of safety. Failure \1/ould effect only .operating per- sonnel. forecast of failure would be im- possible. Failure would effect large~ number of people located downstream, however, some degtee of forecasting dam failure would be impossible. No significant difference in terms of overall assessment of plans. ----·- Rernf.lrks \'lith ~/atana/Oevil Canyon plan is superior« Available information insufficient to draw definite conclusions. Both scenarios judged to be equal. - i " TABLE 8 .. 28: GENERI: COMPARISON OF ENVIRONMENTAL U1PACTS OF A SUS!TNA BASIN HYDRO DEVELOPME:NT VERSUS COAL FIRED THERMAL GENERATION IN THE BELUGA COAL fiELDS Environmental Attributes Ecological: Cultural: Aesthetic/ Land Use: Concerns Sus1Ena Basin Development Potential impact on fisheries due to alteration of ~own steam flow distribution and water quality. Inundation of Moose and furbearer habitat and potential impact on Caribou migration. No major air quality problems, only minor microclimatic changes would occur. Inundation of archeological sites. Inundation of large area and surface disturbance in con- struction area. Creates addi- tional access to wilderness areas, reduces river recrea- tion but increases lake rec- reational activities. Thermal GeneraEion Potential for impact on fisheries resultittg from water quality impairment of local streams and local habitat destruction due to surface disturbances bdth at mine and generating facili- ties. Impact on air quality due to emission of particu- lates so 2 , NOx, trace metals and water vapors from generating facilities. Potential destruction of archeological sites. Surface disturbance of large areas associated with coal mining and thermal genera- tion facilities. Creates additional access and may restrict land use activi- ties. I I I I I I I I I I I I I I I I I I I I I I I I I I. I I I I I TABLt 8.29: OVERALL EVALUATION OF ALL THER~lAL GENERATION PLANS WITH THE GENERATION PLAN INCORPORATING v/ATANA/OEVlL CANYON DAMS ------~------------------------------ ATTRIBUTE SUPERIOR PLAN Economic With Watana/Devil Canyon Environmental Social Overall Evaluatim1 Unable to distingm.sh difference in this study due to site specific nature of impacts No significant overall difference Plan with Watana/Devil Canyon is judged to ~e superior Tradeoffs made: Not fully explored G PREVIOUS STUDIES AND FIELD RECONNAISSANCE 12DAM SITES SCREEN ENGINEEHING LAYOUT AND COST STUDIES 7DAM SITES COMPUTER MODELS TO DETERMINE LEAST COST DAM COMBINATIONS 3 BASIC DEVELOP- MENT PLANS DATA ON DIFFERENT THERMAL GENERATING SOURCES r-------_.__-.., COMPUTER MOO:iELS TO EVALUATE -POWER AN1)! ENERGY YtElLDS -SYSTEMWIDE.~ ECONOMICS RECOMMENDED PLAN GOLD CREEK CRI1'ERIA DEVIL CANYON DEVIL CANYON t-E-C_ON_O_M_I_Cs--tHIGH DEVIL OBJECTIVE WATANA/ DEVIL CRITERIA WATANA/DE:VJL CANYON HIGH DEVIL CANYON ENVIRONMENTAL CANYON DEVIL CREEK ALTERNATIVE WATANA WATANA SITES SUSITNA liT SUSITNA m ENERGY VEE VEE CONTRIBUTION MACLAREN .MACLAREN DENALI DENALt' BUTTE CREEK TY0NE ECONOMIC CANYON .____ ----~ HIGH DEVIL CANYON/ VEE HIGH DEVIL CANYON I WATANA ADDITIONAL SITES PORTAGE CREEK ECONOMIC ENVIRONMENTAL SOCIAL E~·~ERGY CONTRIBUTION PLUS THERMAL LEGEND DIS HIGH DEVIL CANYON DIS WATANA ~STEP NUMBER IN STANDARD PROCESS (APPENDIX A) .. SUSITNA .BASIN PLAN· FORMULATION AND· SELECTION PROCESS FIGURE 8.1 ~~~~ml· PORTAGE CR. 100 120 -t-f ~. !:: U) ::> (/) - 140 160 RIVER MILES ... <C z <C ~ :c ,,.....,., r--- Ff <{ 19.05'-z ..... Cii w 2050!. ,::, w (/) > 2200' _J~ -200 180 OSHETNA RIVER ..----·--' 2ooo• F -I I T'iONt: RIVER . __ __...._ ..... _ 2000 1 RI·VER I I z l 5 I I liJ ~ I . r:l w 1-f I ..... ...J I 5 3 0 z I I <C w • m I ~395!~ c I 2350'! 2535 ~-----=- I • 2 I I~ L2300' 2 I 220 240 260 280 PROFILE THROUGH ALTERNATIVE: SITES FIGURE o~· 5Q)i.t) ~ QCNt>' 5~·' 6.2liJ __ ... _____ ; ____ _ GOLD CREEl< OLSON DEVIL CANYON HIGH UEVIL CANYON DEVIL CREEK WATANA SUSITNAll! ).fEE GOLD CREEK 11\ttlli.l LEGEND COMPATIBLE ALTERNATIVES D MUTUALLY EXCLUSIVE ALTERNATIVES -DAM IN COLUMN IS MUTUALLY EXCLUSIVE IF FULL ;::::::::::::::::::::::;::::::::::::::::-:-:·: SUPPLY LEVEL OF DAM lN ROW EXCEEDS THIS VALUE-FT .. ............. t"4·s·es·············· :~1!\t~\ttj~i:~~\\1\l)l~lf VALUE IN BRACKET REFERS TO APPROXIMATE DAM HEIGHT. M.t\CLAREN DENALI MACLAREN DENALI BUTTE CREEK TYONE MUTUALLY EXCLUSIVE DEVELOPMENT ALTERNATIVES BUTTE CREEK t!IGURE 8.5 I BIR l I I I I, I I I I I I ' •• I I I I I I I --------~--------~----------·---------------------.~---------~·,,~~-· ----~ -U) 0 X ..... t; 0 u -<.Do ..... (!) 0 1000 800 600 1000 LEGEND e COST DEVELOPED DIRECTLY FROM ENGINEERING LAYOUTS COST BASED ON ADJUSl"MENTS TO O VALUES DETERMINED FROM LAYOUTS 0~--~----._--~----~--~~--~--~ 0 200 400 600 800 . 1000 REsERVOIR S"T:ORAGE ( 103 x A F ) DEVIL CANYON 1500 1500 1000 u 500 1000 2000 3000 40QD 5000 RESERVOIR STORAGE ( 103 x A F) HIGH DEVIL CANYON ;. DAMSITE COST VS RESERVOIR STORAGE CURVES FIGURE 8.4 ••• I ·I I I I I I I I I I I I I I I ... I I I 2400 2000 -U>. Q 1600 )( . .... - 1860 LEGEND e COST DEVELOPED OJRECTLY FROM ENGINEERING LAYOUTS . COST BASED ON ADJUSTMENTS TO O VALUES DETERMlNEO FROM LAYOUTS 0~--~--~~--~----~---~-----'~--~----~~ 0 2000 4000 6000 8000 10000 12COO 14000 RESERVOIR STORAGE { to3x A F ) WATANA 1500 1390 . . ; . 1000 -<.00 )( ---1- (/) 0 u 500 . :. o~----~--------------_.~==---'--~• 0 1000 2000 3000 4000 RESERVOIR STORAGE { JQ3 x A F ) SUSITNA lir DAMSITE COST VS RESERVOIR STORAGE CURVES FIGURE 8.5 I I I I I ·-1 I I I I I .I I I I I I I I I -·UO GOO )( ;w -~ 8 400 lOGO LEGEND • COST Ot:VELOPEO DIRECTLY FROM ENGINEERING LAYOUTS COST BASED 00 ADJUSTMENTS iO 0 VALU.ES DETERMINED FROM LAYOUTS o I I ,.. 0 200 400 600 800 1000 1200 1400 RESERVOIR STOF\'AGE (lQ3x A F) \fEE 800 600 ~ ~. Z'. 500 ...... 400 ..... ~ . 350 u 0~--~----._--~----------------------~ 0 200 400 600 800 1000 1200 1400 RESERVOIR STORAGE ( 103 x AF) MACLAREN 1000 2000 3000 4000 RESERVOIR STORAGE { to 3 x AF) . 5000 DENALI DAMSlTE COST VS RESERVOlR STORAGE CURVES ~ FIGURE 8.6 •• I I I I I I I I I I I I I I I I I I I 2200 FT. WATANA 800 MW f..,___,.. __ 2 MiLES -.N-----1475 FT. ~--RE"' REGULATION DAM 38 FT. DIAMETER 800 MW-70MW . 2 TUNNELS ;a 'FT. DIAMETER D£VIL CANYON 550 MW ll50 MW . .....,.. ____ RE • REGULATION DAM 30 MW 30 FT. DIAMETER 800 MW 24 FT. DIAMETER SCHEMATIC. R.EPRESENTATlON OF· CONCEPTUAL 'TUNNEL SCHEMES TUNNEL SCHEME #" I. 2. 3 . 4. ., FIGURE 8.7 ill I I .. ,.·. I I ... I ' I I I I I I I I I I I I I 4000 ~---------..;... ___ 'T"'-_________ ,--______________ .,......____, LEGE NO z Q -' -' ·~ ' 1- CJ) STAGE I STAGE 2 ~. :~:~:~1 0-----Q PLAN E3 o--·-Q PLAN E4 / I E3.2 ~ /3 I I / / I 82000~----------------r-------~~~--r++---------------~+-~ -' ~ a.. <! (.) -' ~ 12 IOQOr-----------------r---~------------+-----------------+---~ o~-----~-------~------~--------~---------------------0 1000 2000 3000 4000 5000 6000 AVERAGE ANNUAL ENERGY-GWH CAPfTAL COST VERSUS ENERGY PLOTS FOR ENVIRONMENTAL SUSITNA BASIN PLANS FIGURE 8.8 .':... I I ,, I I ' t I I I I I I I I I I I I I 0 0 0 I >-1- <..> 3 ~I <X: <..> 10 8 :I: 3:6 (!) 0 0 0 2 715 1980 1990 LEGEND~ D HYDROELECTRIC COAL FIRED THERMAL EZJ GAS FIRED THERMAL 2000 • OIL FIRED THERMAL { NOT SHOWN ON ENERGY DIAGRAM NOTE : RESULTS OBTAINED FROM OGPS RUN L8v9 TOTAL DISPATCHED ENERGY DEVIL CANYON (400 MW} WATANA-1. ( 400 MW) EXISTING a COMMJTTED 2010 0~--~~----------------------------~------------~--------------~ 1980 2000 TfME GENERATION SCENARIO WITH SUSITNA PLAN E 1.3 -MEDIUM LOAD FORECAST- .FIGURE 8.9 2010 [iil . (, ,' ... ·-=~~,.;...._k\\.:..ar...A·- E; ~ 2 0 0 0 t >-.... - :t: 10 8 ~6 0 0 0 >-(.!) ·[!} 4 z w 2 715 1980 1990 LEGEND: D HYDROELECTRIC • COAL FIRED THERMAL E:z] GAS FIRED THERMAL 2230 2000 2010 -Oll FIRED THEHMAL( NOT SHOWN ON ENERGY OJAGRAM) NOTE: RESULTS OBTAINED FROM OGPS RUN L6 0 I TOTAL DISPATCHED ENERGY VEE{400MW) HIGH DEVIL CANYON-2 {400MW) HIGH DEVIL CANYON ~ l( 400 MW) EXISTING AND COMMiTTED 0~--~-------------------------------------------------~--------~ l$60-1990 2000 TJME GENERATION SCENARIO WITH SUSITNA PLAN E 2.3 -MEDIUM LOAD FORECAST- FIGURE 2010 8.10. I •• I I I I I I I I I I I I I I I I I 3 3; ..... -.c: 2 0 0 0 I >-r- (.) ti: <! (.) 10 8 ::r: ?: 6 (!) 0 0 0 715 1980 PEAK LOAD 1990 LEGEND= D HYDROELECTRIC -COAL FIRED THERMAL Ell GAS FIRED T.HERMAL 2000 2010 • OIL FIRED THERMAL {NOT SHOWN ON ENERGY DIAGRAM} NOTE: RESULTS OBTAINED FROM OGPS RUN L607 TOTAL DISPATCHED ENERGY~ TUNNEL. (5SO MW} WATANA-2,(400MW) WATANA -I { 400 MW) EXISTING a COMMITTED 0~---L----------------------------------------------------------~ 1980 1990 2000 2010 TIME GENERATION SCENARIO vVITH SUSJTNA PLAN E3.1 [i] ~MEDIUM LoAo FORECAsT-· APDr~·· Q FIGURE 8.1 I UDlO I I' I I I I I I I I I I I I I I I I I :::· ~ 0 0 0 1.2 I •• 8 >- t:: ~ <( () ::r: 3: (!) 0 0 0 .4 8 6 - 4 I >- (!) a:: w z w 2 1980 1990 LEGEND: . D HYDROELECTRIC lilliill COAL FIRED THERMAL D GAS FIRED THERMAL 2000 OIL FIRED THERMAL (NOT SHOWN ON ENERGY DIAGRAM) NOTE: RESULTS OBTAINED FROM OGPS RUN LC 07 TOTAL DlSPATCHED ENERGY (980 1990 TIME DEVIL CANYoN (400MW) WATANA (400 MW) EXISTING S COMMITTED HYDRO 2000 1272 2010 2010 GENERATION SCENARIO WITH SUSITNA. PLAN E 1.5 -LOW LOAD FORECAST- FIGURE 8.12. i I I I I I I I 0 I I I I I I I I I I I ~~~--------------~--------~--------------------------------------------~ 3: :e 0 g 2 t >- 1- (.) ~ <( < .. .> I :c .~ {!) 0 0 0 16 12 I 8 >- {!) a:: w 2 w 4 1980 1990 LEGEND: D HYDROELECTRIC m COAL FIRED THERMAL ll1) GAS FIRED THERMAL 2000 -OiL FIRED THERMAL( NOT SHOWN ON ENERGY DIAGRAM) NOTE: RESULTS OBTAINED FROM OGPS RUN LA73 TOTAL DISPATCHED ENERGY 1980 1990 TIME DEVIL CANYON · ( 400 MWl WATANA-~ (400 MW) WATANA -1 (406 MW) 2010 GENERATION SCENARIO WITH SUSITNA PLAN E 1.3 HIGH LOAD FORECAST FIGURE 8.13 fAil-