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HomeMy WebLinkAboutSouthcentral Railbelt Area Hydroelectric Power Study 1978RAI 004 r4FORMATION BROCHURE \ ' LOOKINQ l>OWAI.ST/f&A!f -.......::: __ -.....::: 7bwARD.s IJEn~ C"'IYYON ZJAHS/f"e ALASKA DISTRICT-CORPS OF ENGINEERS-'MAY 1978 2046-78 RELEASE T~~y Authorized by .E::. Date Z-It - DATE HIGHSMITH · 42·225 RAI 004 May 78 ISSUED TO PIIII'IED IN u.s.A. MEMBERS OF THE ALASKA DISTRICT, ARMY CORPS OF ENGINEERS, AT THE ORIENTATION ON THE UPPER SUSITNA RIVER ON MAY 19, 1978. Col George R Robertson, Alaska District Engineer since June 1976. Lt Col James Fero~ Deputy District Engineer since June 1977. Weldon Opp, Act~g Project Manager, Susitna River Project. (fi:/~ H~r1an "Hod 11 Moore·, Chief,, Foundations & Materials Branch, Engineering Division Lyman L. Woodman, Pub 1 i c Affairs Officer Maj Allan Wylie, Asst Project Manager, Susitna River Project · Itinerary: 0900 0900-0910 0915-0945 0945-1000 1000-1045 1045-1115 1115-1130 1130-1200 1200-1245 1300-1430 1430-1500 1510-1520 • Governor Hammond's Visit to the Upper Susitna Project Start from Governor's Office, MacKay Bldg. Enroute to Merrill Field Enroute to Talkeetna Transfer to Helicopters Enroute to Watana Briefing & Tour Site, Mr. Harlan Moore Enroute to Devil Canyon Briefing & Tour of Site, Mr. Weldon Opp Enroute to Talkeetna Briefing at the Rainbow Lodge, Col. Rober~son Enroute to Merrill Field Enroute to Governor's Office, MacKay Bldg. .. ; J WHAT IS THE SOUTH CENTRAL RAILBEL T STUDY? A 1972 Senate Public Works Committee resolution requested that the Corps of Engineers consider the question of providing power to the Southcentral Railbelt area of Alaska. Throughout the States, inves- tigations of energy sources are underway. Since power development, in particular hydroelectric power, is included in the Corps of Engi- neers Civil Works program, the Corps was asked to consider the pos- sibilities of hydroelectric power developments along the Susitna River. The Southcentral Railbelt area of Alaska extends from the fairbanks vicinity southward through the Kenai Peninsula. About 75 percent of the State's population lies within this area. All the river systems, lakes, and coasts south of the Alaska Range are encompassed as pos- sible sources of development. Some 40 potential hydroelectric power sites could supply power. The first 2 years of the study were spent investigating specifically the desirability and feasibility of the Upper Susitna River as a hydro- power source. A variety of factors--including the central location of this river, its great hydropower potential as defined in earlier studies by the U.S. Bureau of Reclamation, and the economical and environmental aspects of development--pointed to the Susitna River as the logical area to study first. This portion of the study culminated with a recommendation by the Chief of Engineers for advanced engineering and design studies for a proposed two-dam development of the Upper Susitna River. In 1976 a feasibility report and draft Environmental Impact Statement were forwarded through channels to the Chief of Engineers. This, with comments, was transmitted to the Board of Engineers for Rivers and Harbors. The Chief of Engineers then circulated the reports to interested cabinet level agencies and the Governor's Office, State of Alaska, for review and comment. Based on these responses the Chief ofEngine_e_rs f'in!ilJz.ed !he_Eliin)~Jl_l.l~IT_Jn?. 'm-~Ythe-stuc:Iy reporr·a-nC:rr-fnal EIS were sent to the Office of Management and Budget who requested that the benefit-cost status be verified prior to the project progressing to Phase I. The Chief of Engineers reallocated $3 million to accomplish the requested verifications. This supplemental feasibility study is currently being accomplished. ALASKA HYDROELECTRIC FEASIBILITY STUDY 2 I AREA DESCRIPTION The Susitna River, with an overall drainage area of 19,400 square miles, is the largest stream discharging into Cook Inlet. The basin is bordered on the south by the waters of Cook Inlet and the Talkeetna Mountains, on the east by the Copper River plateau and the Talkeetna Mountains, and on the west and north by the towering mountains of the Alaska Range. Upstream from the proposed Devil Canyon damsite, the river drains an area of 5,810 square miles. Principal tributaries of the Upper Susitna Basin are the silt-laden Maclaren which emanates from glaciers of the Alaska Range as does the Susitna River itself, the less turbid Oshetna, and the clear-flowing Tyone. Roughly 95 percent of the total annual flow of the river occurs between May and September. The Southcentral Railbelt area of Alaska contains the State's two largest population centers, Anchorage and Fairbanks, and almost 3/4's of the State's total population. The Anchorage area alone contains over half the residents in the State. Both Anchorage and Fairbanks are the regional economic centers for the Southcentral Railbelt area. Fish inhabiting the Susitna Basin are divided into two major groups: resident and anadromous. Salmon are known to spawn in many of the sloughs and tributaries of the Susitna River below Devil Canyon, how- ever, surveys indicate that salmon are unable to ascend the turbulent Devil Canyon, and thus, are prevented from migrating into the Upper Susitna River Basin. Grayling, rainbow trout, lake trout, Dolly Varden, whitefish, and burbot comprise the principal resident fish populations. The Upper Susitna Basin also contains waterfowl, raptors, caribou, moose, bear, Dall shee~, mountain goats, wolves, wolverines, and other fur animal species. Vegetation on much of the basin is classified as moist or alpine tundra, with most of the area in and adjacent to the main river channel below the Maclaren River classified as either upland or lowland spruce-hardwood forest. 3 WHAT ACTION HAS BEEN TAKEN?} • Numerous public meetings and discussions with concerned agencies, organizations, and individuals were held. The first public meetings were held in Fairbanks on May 6, 1974~ and in Anchorage on May 8, 1974. Transcripts of these hearings are available at the Corps' office in Anchorage. A second set of public meetings was held in Anchorage on May 27, 1975 and in Fairbanks on May 29, 1975, in order to discuss possible alternatives. The selected plan of development was presented to the public at meetings conducted in October 1975. • An inventory and evaluation of the environmental, esthetic, and rec- reational resources of the Susitna River area was completed by an architect-engineering firm employed by the Corps. This inventory helped provide some of the backgorund for the Environmental Impact Statement. • A special task team was set up at the Corps' office to evaluate envi- ronmental, economic, engineering, and social aspects of hydropower development of the Upper Susitna River as well as possible alterna- tives to this action. • Several Federal and State agencies conducted investigations and provided data relative to environmental, economic, and other study aspects. • Based on the results of the study, on December 12, 1975 the District Engineer recommended construction of a two-dam system and related transmission facilities at a 1975 first cost of $1,531,800,000. The Division Engineer concurred with the recommendation. • In order to establish a unified State position on the project, Governor Hammond appointed a cabinet level task team to review the findings and conclusions of the District and Division Engineers. Predicated on a number of stipulations and conditions, the State task team recommended a unanimous endorsement of the proposed plan. The stipulations included a number of social, economic, and environmental studies which sould be conducted during post authorization analysis. • The Board of Engineers for Rivers and Harbors recommended that the report be accepted as the basis for proceeding with more detailed economic, environmental, and engineering studies. • In June 1976, the Chief of Engineers recommended authorization of the Phase I design memorandum stage of advanced engineering and design of the plan as proposed by the District Engineer. • The Governor reviewed the Corps of Engineers reports and in November 1976 provided the Chief of Engineers with a letter concurring with the recom- mendations. 4 1 In January 1977, the Office of the Chief of Engineers finalized the Environmental Impact Statement and Feasibility Report ~nd forwarded them to the Office of Management and Budget in May. • OMB notified the Chief of Engineers in September of the need to verify cost-benefit status prior to progressing to Phase I. • In October 1977, the 94th Congress authorized $25 million for advanced Engineering and Design and the President signed Pl 94-587, Water Resource Development Act of 1976. The Alaska Hydroelectric Power Development Fund was also authorized in the Act. • The Chief of Engineers reallocated $3 million to conduct a supplemental feasibility study that would primarily increase the geological data available. This data in turn would be used to verify the cost-benefit status of the project. • On February 22, 1978, the Corps signed an agreement with the Bureau of Land Mangement to conduct geological explorations. • In March 1978, an exploration crew was mobilized to the site and began drilling test borings through the river ice at the Watana site. • By May 1978, four test holes had been completed and drilling operations started on the abutments. 0 II 10 Ill 20MII .. SCALE 5 VIABLE ALTERNATIVES I The coal alternative is, effectively~ the "without" condition, the probable future that would develop if no Federal action were taken to provide electrical power through a hydroelectric generation development. It is the economic standard against which each of the hydropower plans is tested. That is, the power benefits of a given hydro system represent the cost of producing the same amount of power by construction and operating a conventional, state-of-the-art, genera- ting system using coal as fuel. Included in all cases are the costs of the necessary transmission systems to bring the power to the same load distribution centers in the Anchorage and Fairbanks areas. Thus, a benefit-to-cost ratio of greater than one (1.0) indicates that a hydro system is more economical than its coal competitor, while a ratio of less than unity indicates that it is eocnomically inferior. For any given alternative coal system, the sum of the energy and capacity benefits is identical to the costs giving a benefit-to-cost (B/C) ratio of 1.0 and no net benefits. ENGINEERING <?::_::-:~,:::\:':_:-.:. .·...... .:i ;~ ECONQftiiCS 6 The coal-fired development most directly comparable to the hydropower alternatives would be a single large complex located near Healy, with a transmission system essentially identical to the Anchorage-Fairbanks intertie provided by the hydro plants. However, such a massive capital investment by private interests is less likely than continued separate expansion of the existing local generation-distribution systems. For this reason, the coal alternative considered hereafter consists of two mine-mouth plants, one at Beluga serving the Anchorage-Kenai Peninsula load center, and one at Healy serving the Fairbanks load center. No transmission intertie would be provided. It was concluded in the study that, of the existing fossil fuels avail- able for use in the Anchorage and Fairbanks areas, only coal provided sufficient, recoverable reserves for long range energy development. Furthermore, by comparing the hydro alternatives to coal, it was found that the two-dam Upper Susitna system consisting of Devil Canyon and Watana best accomplishes the economic objectives. Of the alternatives evaluated, the two-dam system has the highest benefits-to-cost ratio at 1.3 and the maximum net annual benefits at $33,856,000. Consequently, the selected hydro plan is more economical to develop than its coal counterpart. It is evident that no means of producing a meaningful output of elec- trical energy has been found to be free of significant adverse environ- mental effects. The plan which minimizes the unavoidable adverse impacts on fish and wildlife values while providing beneficial contri- butions to air and water quality and social well-being is considered to contribute most to the environmental quality objectives. On this basis, of the alterantives evaluated, the system of two dams at Devil Canyon and Watana was selected as the environmental quality plan. 7 THE SELECTED PLAN I The 1974 combined energy consumption for the Anchora~e and Fairbanks load centers was approximately 2,000 gigawatt hours (Gwh). Due to the continuing rapid growth in the Southcentral Railbelt, the pro- jected energy consumption is estimated to be 15,000 Gwh by the year 2000. The recommended plan calls for the construction of two high head dams on the Upper Susitna River, and related transmission facili- ties to convey the energy to the Anchorage and Fairbanks power markets. the sequence of construction would consist of Watana dam and related facilities being built first, followed by the downstream Devil Canyon dam project. PROJECTED ENERGY DEMAND MILLION KWHR 20,000 15,000 5,000 0 DATA FROM ALASKA POWER ADMINISTRATION 8 The study indicated that Watana construction could begin as early as _12JiQ~od::-woul d requf_r::~ ___ 6 years for completion, at;._wbichtime 3,100 Gwh of firm enerqy-wouTd be avaflablerurconsUni'ption. Devil Canyon con- struction would be begun in 1985 and would be completed in 1990, thus, adding an additional 3,000 Gwh to the system. Present plans call for the Alaska Power Administration to operate and maintain the projects, and market the energy. Of the energy produced, 75 percent would be consumed in the Anchorage area, with the remainder going to Fairbanks. It is estimated that 75 percent of the utility load being generated by fossil fuels, at the time the Watana project is brought on line, could be displaced by Susitna hydro. + G I 0 u c ,~ i-1 9 WATANA PROJECT FEATURES] Type Construction Structual Height (ft) Crest Elevation (ft. MSL) ~la:dmum Head (ft} Crest Length (ft) Area Inundation {acres) Storage Capacity (acre-feet) Active Storage (acre-feet) Annual drawdown (ft) Reservoir length (miles) flependable Capacity (MW) r inn Energy ( GWff) Secondary Energy Spil1w;1y Desiqn Flood (cfs) Re~ervoir Sediment Encroachment over 100 years (percent) Access Road (miles) Project Co~ts (1,000,000) Earthfi 11 810 2,210 720 3,450 43,000 9.624,000 6.100,000 100 54 /-7crs· 3,080 440 165,000 4.2 37 l ,088 10 r . , ... .,. . ~' i \ ! ~ f i i I· f 1 I ·I ! • ll \ -t~---- -1 ----- -u -! -R . -~ -I -I -I -I I ·I -I -l a -1 I -1 t~ ~ tili '" ~J -I~ -~ I ;w -~ -I -i -§ -i -I 11 f: n -i -I -§ -~ DEVIL CANYON PROJECT FEATURES Type Construction S tructua 1 Height ( ft j Crest £levation (ft. MSL) Maximum flead (ft) Crest Length (ft) Area Inundation (acres) Storage Capacity (acre-feet) Active Storage (acre-feet) Annual drawdown (ft) Reservoir length (miles) Dependable Capacity (MW) Firm Energy {GWH) Secondary Energy Concrete, thin-arch 635 1,455 575 2,475 7,550 1,050,000 600,000 5 28 ,---685. . 3 ,020. Spillway Design Flood (cfs) Re~ervoir Sediment Encroachment 360 228,000 over 100 years (percent) Access Road (miles) Project Costs (1,000,000) 6.5 27 432 \ I ~ I I. ~ ~ ~ ~ r· H ,. li ~ lj ll f. ~ t I ~----------------------------------! 12 4/(H If"<;£! fH~ IIIH .. St:CT!OIV lrst of m•rt1•1 COII(Udy. (I 1115 ---TtW:~ Gf tmfldttilftlll,,ll t•fl • r11ruct Dfcct Ct7ttftucfhot: Oloc.i'l __ _..-- (fftfrrflto/ ~ fl(ttJI Cl ~~~ ·-.) JICCTION THifV PCN.TOCK AND POWCif PLANT y --+-+->+-.,CL,.. ~ ..... , 0 C Cl, 101'5 ' ,_,_.,_...,. UPSTRE:AM t:LE:VATIOIV OlVllOPEI> <4-LON$ AXIS ()f DAtf 13 EN-VIRONMENTAL CONCERNS} • Construction of the two-dam Devil Canyon and Watana proposal would significantly reduce the late spring and early summer flows of the river~ and substantially increase the winter flows. This could lead to anadromous fish disorientation during migration to spawning beds downstream from the projects. This may also dry up some of the clear water sloughs which are normally recharged during flooding. On the other hand~ the regulatory effect of the projects may increase fish egg survival by reducing fan floods and by maintaining sufficient winter flow. • The normal annual sediment loads consist of heavy concentrations in the summer months and virtually zero concentrations during the winter. With the projects, roughly 95 percent of the summer sediment will settle in the reservoir, however, that which remains in the solution will be released to downstream fisheries throughout the year, thus increasing winter sediment transport. This could have a positive summer effect on fisheries and a negative winter effect. In addition, although present studies do not indicate a problem, degredation of the downstream main channel could render the spawning sloughs and tribu- taries temporarily inaccessable to certain fisheries. • ~Jithout certain precautionary measures, the downstream water quality could be diminished. Experience gained from other large reservoirs indicated that problems with temperature control, nitrogen supersatu- ration and dissolved oxygen concentrations may prevail. It is antici- pated, however, that the combined effects of the downstream river channel, the physical geometry of the projects, and specific design features, will adequately mitigate the possible adverse impacts. In fact, the downstream water quality may ctctually be enhanced by the projects. • Upstream impacts would generally be a result of the reservoir impound- ments. Although the Devil Canyon reservoir water level will remain relatively constant, the Watana reservoir will fluctuate as much as 100 feet per year. This could lead to fisheries problems in adjacent tributaries. Ice shelving, the impediment of caribou migration, and loss of moose habitat may occur as a result of the reservoirs. In addition, the pt·oposed reservoirs at Devil Canyon and Watana are located along a major flyway for waterfowl" Very few waterfowl appear to nest on the section of the river that would be flooded by these reservoir proposals, but the reservoirs could provide suitable nesting areas not now available for waterfowl migrating through the basin. The loss of habitat for bears, wolves, wolverines, Dall sheep, and other animals appears to be minimal. Other birds, including raptors~ songbirds, shorebirds, and game birds. do not appear to be significantly affected by the reduciton of habitat in the area of the proposed dams and reservoirs. although some habitat wi11 be lost for all species of wild- 1 ife. 14 • The construction of the proposed hydroelectric project would have an impact on a number of present and projected recreational activities both in the immediate dam and reservoir areas and downstream from the dams. At the present time, the Susitna River upstream from Portage Creek to the Denali Highway bridge is a free-flowing river with a few signs of man•s activities. The construction of dams in the river would change sections of the free-flowing river into a series of manmade lakes. The violent~ whitewater section of the river through the area known as Devil Canyon would be substantially inundated by a dam at the Devil Canyon site. Other areas of the river would also be changed from river-oriented recreational opportunities to lake-oriented recrea- tional activities. Improved road access into some areas of the Upper Susitna Basin would substantially increase pressures on all the resources impacted by outdoor recreational activities within these areas. The construction of project-oriented recreational facilities would sub- stantially increase the recreational use of the areas around the pro- posed dams and reservoirs. • Only one archaeological site has been examined within the study area of the Upper Susitna Basin, and it has never been excavated. This is the Ratekin site, several miles east of the Susitna River near the Denali Highway. The Divison of Parks survey projects a total of 40 zones of possible archaeological interest within the Devil Canyon and Watana impoundments. An archaeologist has examined the exploration site and delineated those areas with a high probability of archaeological interest. Most areas fall outside of current activity zones, however, where a possibility of finds exist the archaeologist will be available for an onsite examination prior to the start of any work. 15 UJ c( w a: c( a: w ~ D D. D DEVIL CANYON a: D WATANA > I .J c( -1-z w 1- D 16 D. [ SUSITNA HYDRO Development of the Susitna River would augment efforts toward energy independence through the annual conservation of an equivalence of 113 billion cubic feet of natural gas, or 15.2 million barrels of oil. In a 11 probabi 1 ity, the Prudhoe Bay o i1 deve 1 opment wi 1l be fa 11 owed by Prudhoe Bay natural gas, PET-4 oil reserves, and Outer Continental Shelf discoveries. With the national quest for Alaska's natural resources and the consequential energy demand necessary for exploita- tion, early development of Devil Canyon and Watana may provide a solu- tion to State and national energy resource requirements. Unlike most civil works projects, the entire outlay for the construction and opera- tion of the system would be paid back to the Federal Treasury through revenue returns from the sale of energy to local consumers. The jobs that would be created during the 11-year construction phase would create opportunities for the under or unemployed workers. From a regional standpoint, the project would provide an immeasurable stabilizing effect on the energy system of southcentral Alaska. There would be adequate energy available to meet demand and incidental bene- fits associated with an integrated transmission system. Electrical utility costs would be lower than for other alternative power sources, and rate hikes resulting from fossil fuels cost increases would be in proportion to the limited amount of conventional generation in the integrated system. Additional benefits could be realized from limited flood control and recreational enhancement. 17 STATE PLAN OF ST~DY I In June 1977, the State of Alaska asked the Corps of Engineers to prepare a Phase I Advance Engineering Plan of Study that would lead to a Phase I Design Memo as required by the 1976 Water Resources Act, PL 94-587. The Plan of STudy was completed in September 1977 and sub- mitted to the State of Alaska. The budget incorporated into this pro- posal totaled $23.4 million. The State's review comments were returned to the Corps in January 1978. All comments have been incorporated into the Plan of Study except those from the Department of Fish and Game. The discussions on ADF&G comments are centered around the relative magnitude of the proposed activities to determine feasibility. 18 HYDROELECTRIC POWER DEVELOPMENT --WATANA AND DEVIL CANYON A Potential Power Project of the Army Corps of Engineers By direction of Congress, the Corps' Ala.ska District is studying the feasibility of developing the hydroelectric potential of the upper Susitn~ River as a means \f supplying energy for the rapidly expanding power demand of the Scuthcentral Rail~lt area of Alaska. The District prepared a feasibility report in 1975 which included a recommendation for construction of dams at Devil Canyon and Watana. The report was forwarded to Washington, D.C. for review and public comment. Subsequently Congress authorized $25 million to be spent for Phase I Advanced Engineering and Design of the project, but • funds for this have not been provided. The authorizing legislation also provided the option of a State-Federal joint venture whereby the State would provide project fund- ing, and the Corps of Engineers would do the work. After project completion, the dams would be owned and operated by the State. On September 28, 1977 the Corps delivered to the State a study outline draft that detailed the cost and established schedules for the several years of additional plan- ning required prior to any final determination regarding project construction. At the direction of the Office of Management and Budget the Corps has now begun intensive effort to obtain more information to verify the benefit/cost feasibility indicated in the 1975 report. This information is needed before OMB can recomme~d proceeding with Advanced Engineering and Design. Geological exploration is under way at Watana now. Drilling equipment and related materials have been moved by cat train over snow and frozen ground to the Watana area. Two tracked cargo vehicles and drums of fuel have been air-dropped to that area, and helicopters are used to relocate ~quip­ ment at the work site to minimize any adverse effect on the terrain. Drill crew~ lodge at Talkeetna and commute to and from river by helicopter. Exploratory holes are being drilled to determine the nature of the underlying structure at the damsite. Four dri 11 ho 1 es through the river ice have been co~ 1 eted. The data being co 11 ec ted will help update the constructior. cost estimate. That estimate combined with a revised economic analysis will be used to 'compute a new benefit/cost ratio. The District will complete the supplement report by January 1979 and submit the document for referral to OMB. The plan, as presently conceived, is a two-dam system which would inundate som~ 50,500 acres including an 82-mile reach of the Susitna River upstream from Devil Canyon Dam. The canyon reservoir would have a water surface of about 7,550 acres at normal full-pool elevation. It would extend upstream about 28 miles, confined within the canyon. Reservoir width would vary from about 1/4 to 3/4 miles. Watana Dam, about 2 miles above the Devil Canyon reservoir, would inundate ·about 43,000 acres at normal elevation. It would extend some 54 miles upstream from the dam and would average 1-1/4 miles in width. Power distribution would require transmission lines from Watana to Anchorage and Fairbanks. The transmission corridor would be about 365 miles long and average 200 feet in width. The total .right-of-way would cover abou~.8,100 a~r~s ... This system would provide at least 6.1 billion kt~ of energy annua11y, equivalent to consumption of some 10.7 million barrels of oil per year. · · · · MAY 1978 •