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Home My WebLink AboutDefinite Project Report Cooper Lake Hydroelectric Project 1955.. -.. ... dill ... ... • - DEFINITE PROJECT REPORT COOPER LAKE HYDROELECTRIC PROJECT KENAI PENINSULA, ALASKA FERC PROJECT NO. 2170 (1fujor) • r - • \ .- ... •• • . .tII .. • -,) DEFINITE PROJECT REPORT COOPER LAKE HYDROELECTRIC PROJECT KENAI PENINSULA, ALASKA for CENTRAL ALASKA POWER ASSOCIATION, INC. (Chugach Electric Association, Inc. Matanuska Electric Association, Inc. Board o:f Directors: Herman Schultz Arthur Schroeder Justine M. Parks E. A. Jarvi John King --, Homer Electric Association, Inc. Kenai Lake Electric Association, Inc.) Marlin S. Stewart Acting Manager Dec. 29, 1955 ARLIS Alaska Rcsourcc~ Uh\<LI1' "'-: 111f?~ation Sel'\'iCII Librar) l3ulilhng. SUl\~ 111 3211 Pr()\'klcncc DrIVe .AnclIoragc, AK 995084614 PORTLAND • ORCGON HOlT H P A CI F IC ( 0 N S U l TA N T S ANCHORAGC. ALASKA - (' • .. .. .. .. .. .. • j -. .; ,. . ...) / - Definite Project Report on Cooper Lake Hydroelectric Project Dec. 29, 1955 ERRATA SHEET letter of Transmittal, page 2, first line Acknowledgments, first name right column Report Summary, . page 6, 1st line, Par. C Report Swmnary, Plate C Appendix A, page A-14, 5th line from bottom Appendix G, Plate G-5 Appendix G, page G-6, 4th line, 4th Para. Appendix a, page a-lO 2nd line from bottom page a-ll 1st line, 2nd Para .. page H-12.4th & 5th line from top page H-13 4th line, 4th Para. page H-22, tabulation page B-25, 4th line, Para .. I-l page H-26, 2nd line, 5th Para .. page H-29, last line, 5th Para. page H-33, paragraph 10-& Plate H-2 Appendix L, pages 1-1 & 1-2 tabulation , should read: Association : should read -Marina : add lIavera!elf before "Monthly oad--" . : Note C should read: Award of Contract : ShoUld read 1490 45' Unit of graph should read in 100 KW and decimal point misplaced on speci- fication of both Anchorage and Chugach average demands: should read: 7, 370 K"il and 5,840 KW respectively • ShoUld read: upstream slope will be 1 on 2t. : Should read: Arm and westerly • Should read: generat,!! its own : Should read: -Bureau of Recla- mation-Eklutna project for 9000 KW : Omit words: "this meeting". : Opposite: Stetson Creek Div- ersion and Ptarmigan Creek DiverSion under Plans #3 and #4 add: ul.t. in front of yes. - : Should read: Plate H-l Should read: available : Should read: $'3'6,'000 : Should read: CO 2 : Anchorage should be spelled properly on load line. : heading of first columns should be Unit instead of Uni t Price:-- January ll, 1956 PORTLAN.D • ORIIGOH N 0 RT H P A ( I Fie ( 0 N S U l TAN T \ A",CHORAGII. ALASKA - '. • .. ... .- .. • - -J -.. - NORTH PACIFIC CONSULTANTS COMPLETE ENGINEERING, INDUSTRIAL, ECONOMIC SERVICES IV ... N BLOCH "'NI) AS~OCI"'TU POflTLAHD, O ... OON N. W. H ... NIII ... NO ASSOCI ... TIS POIln. ... ND. O"I:OOM ROSIIIT W. RIETHIIII,.OIllI) A.SOCI ... TU "'MCItOIl ... OK. ......... K ... 611 Park Building Portland 5, are • December 29, 1955 P. O. Box 3008. EASTCHISTIII BR ... NCH ANCHOII ... <lI. AL.ASK ... (PHONI S63SI) 6 11 P ... IIK BUILI)ING PoRTL.ANI) ,. OIllIl:I:ON CA .. ITOL 1·3300 RE: Cooper Lake HYdroelectric Project ~enai Peninsula, Alaska Central Alaska Power Association P. o. Box 2058 Anchorage, Alaska Gentlemen: We submit herewith the Definite Project Report on the proposed Cooper Lake Hydroelectric Project. This Report was prepared in accord- ance with the stipulations of the Engineering Contract entered into be- tween Central Alaska Power Association, Inc. and North Pacific Consult- ants on June 7, 1955. This contract received administrative approval by the U.S. Rural Electrification Administration on August 4, 1955. !he preparation of the Definite Project Report embodied extensive field work in the Cooper and Kenai Lakes areas by North Pacific Consult- ants. Subsurface exploration of various project features by seismic as well as by drilling, pitting and trenching probings was carried out under the supervision of North Pacific Consultants by the Gahagan Con- struction Company's Geophysical Exploration Division of New York, and by crews of the Central Alaska Power Association, Inc. All engineering and economic considerations of the project received the constant review of members of the Board of Consultants of North Pacific Consultants. It is the conclusion of North Pacific Consultants and its Board of Consultants that the proposed Cooper Lake Hydroelectric project is feas- ible from all engineering, economic, and costs considerations, and that construction of this project at the earliest possible date is highly des- irable to meet the growing power demands of the electric power systems of the Chugach Electric Association, Inc., Matanuska Electric Association,Inc., - - • • • • • • • - - -J -.II -.- /. - - 2 Hamer Electric Association, Inc., and the Kenai Lake Electric Aasocia- tion, Inc. It is the further conclusion of your Engineers that the in- tegration of the proposed hydroelectric project into the proposed Genera- tion and Transmission pool of the above~entioned aqencies will qreat- ly ~rove reliability of service to consumers and will result in appre- ciable savings in the oost of such service. It is also the recommendation of North Pacific Consultants and its Board of Consultants that your Aasociation give ~ediate consid- eration to the eventual inclusion of the diversion of the stetson Creek drainage as an integral part of the proposed Cooper Lake Hydroelectric Proj ect. SUbstantial operational and cost advantaqes will accrue to the entire project fran such an inclusion. It is our opinion, therefore, that the proposed construction of the Cooper Lake HYdroelectric Project is a sound and desirable venture for the Central Alaska Power Association, Inc. Respectfully submitted: Nom:! PACIFIC CONSlJI..TAN'lS: Consultant-Board of Consultants) - .. .. .. • • .. • • • • • • - - ACKNOWLEDGMENTS The Cooper Lake area is extremely-rugged. Access is diffi- cult. The terrain is rough, and brush almost impenetrable. The weather is often inclement. Such conditions are hard on men and equipment • Commencement of requisite field work in the area was late due to delay-in authorization of this project. Thus, a very real problem faced North Pacific Consultants in the need to complete all field work before weather conditions would foreclose effective field exploration. Without the splendid cooperation of all local people in the Kenai Peninsula and Anchorage area, the job could not have been done during the time available. The devotion of field crews on survey-s and geological exploration, the whole-hearted support and interest of local merchants in expediting procurement of necessar,y supplies, the enthusiasm of most citizens regarding the Cooper Lake project, were important factors in facilitating a difficult task. North Pacific Consultants therefore wishes to acknowledge gratefully the excellent cooperation tendered by-Federal and Terri- torial agencies, by the management of the Central Alaska Power Asso- Ciation, Inc., and most particularly by those listed below: Alex Bolam, Moose Pass ronald C. Cameron, Kenai Jack Chisum, Kenai Eldon Gallear, Anchorage Leonard A. Gilliland, Cooper Landing Jack Lundeen, Anchorage John H. Sattler, Seward Arthur G. Schroeder, Cooper Landing Norman Snyder, Anchorage Carl Steeby-, Anchorage Alaska Exploration and Development Corporation, Anchorage Alaska Sportsman & Charter Service, Anchorage Alaska Steamship Company, Anchorage Alaska Technical Supply, Anchorage Alaska Transportation Co., Anchorage Anchorage Daily-Times Anchorage Daily-News Bear Paw Flying Service, Seward Birch Haven Harina, Cooper Landing G. C. Chisum Flying Service, Kenai Durant's Hardware, Seward Estes Brothers, Moose Pass Food Center, Anchorage Grocery Supply, Inc., Anchorage Hami.lton's Store, Cooper Land:ing Kenai Lake Lodge, Cooper Landing Kennedy Hardware, Anchorage Mac f s Fotc Supply-, Ancho,rage Miller-Dalton Company, Anchorage Our Point of View Lodge, Moose Pass Scotty-fs Cabinet Shop, Anchorage Seward Hardware, . Seward Seward Trading Co., Inc., Seward Sny-der Office Supply, Anchorage Warner', Cold Storage and Market, Seward POIITLAND • OlUtGON NOR T H P A CI Fie CON S U LT ANT S ANCHOIlAGIt, ALASKA - -.. • ,. • • .. .. • .. .. TABLE OF CUNTENTS Reoort Swmimry and Recommendations 1. Introduction -~ - - - - - - - - - - - - - - - - - - - - - 1 2. Previous Investigations - - - - - - - - - - - - - - - - - 1 3. Population and Economic Trends - - - - - - - - - - - - - -1 4. Description of Project (a) Project Plan - - - - - - - - - - - - - - - - - - - - (b) Climate - - - - - --- - - - - - - - - - - - - - - - (e) Ran-off - - - - - - - - - - - - - - - - - - - - - - - ( d) The Complete Development - - - - - - - - - - - - - - (e) storage and Regulation - - - - - - - - - - - - - - - (f) Diversion of Stetson Creek - - - - - - - - - - - - - (g) Fish and Wildlife, Land Use and Natural Resources - - (h) Construction Schedule - - - - - - - - - - - - - - - - S. Geologic Conditions (a) DBa Site - - - - - - - - - - - - - - - - - - - - - - (b) Tacnel - - - - - - - - - - - - - - - - - - - - - - - (c) Conduit, Surge Tank and Penstock - - - - - - - - - - (d) Powerhouse - - - - - - - - - - -,-- - - - - - - - - (e) Stetson Creek Diversion - - - - - - --- - - - - - - 6. Project Plan (a) DBa - - - - - - - - - - - - - - - - - - - - -~ - - - (b) Reservoir - - - - - - - - - - - - - - - - - - - - - - (c) Intake and Tunnel - - - - - - - - - - - - - - - - - - (d) Ptarmigan Creek Pickup - - - - - - - - - - - - - - - (e) Condu.it and. Surge Tank - - - - - - - - - - - - - - - (r) Penstock - - - - - - - - - - - - - - - - - - - - - - (g) Powerhouse - - - - - - - - - - - - - - - - - - - - - (h) Turbines and Generators - - - - - - - - - - - - - - - (i) COntrols - - - - - - - - - - - - - - - - - - - - - - 7. Hydroelectric Power (a) Market Area and Characteristics - - - - - - - - - - - (b) Available from. Project - - - - - - - - - - - - - - - (c) Correlation of Generation and Use - - - - - - - - - - ( d) Estimated Worth at Plant - - - - - - - - - - - - - - 8. Estimated Cost of Project - - - - - - - - - - - - - - - - 9. Feasibility - - - - - - - - - - - - - - - - - - - - - - - F'ORTI.AND OR liGON J F I ( ( N ~ U l TAN T ~ ANCHORAGIl. A\.ASKA 1 2 2 2 2 2 2 3 3 3 3 4 4 4 4 4 5 5 5 5 5 5 6 6 6 6 6 7 - - - ,. .. .. • • • • ,1111 .. .. J - - - - TABLE OF CONTENTS (Continued) 10. Conclusions - - - - - - - - - - - - - - - - - - - - - - -7 11. Recommendations - - - - - - - - - - - - --- - - - - - -7 PE1n'~.DA.T.A - - - - - - - - - - - - - - - - - - - - -8 Plate A -Photo of Lake and Basin It B -It II Cooper Creek and Dam. Site It C -Construction Sohedule APPENDICES A. History and Settlement B. Natural Resources C. Economio Development D. Topographio Features of the Projeot E. Hydrology F. Geology and. Foundation Exploration G. Hydraulio Analysis H. HYdroeleotrio Power I. Structural Design J. Plant Operation and Maintenance K. Federal and Territorial Jurisdiction L. Projeot Cost Estimates M. Annual Charges and. Feasibility N. Proj,eot Drawings FtOIlTLAND • OIlEGON N 0 IT H P A ( I F I ( ( 0 N S U L TA N T S ANCHO"AGE. ALASKA - - • • • - • - • • -J • - - REPORT SUMMARY AND RECOMMENDATIONS 1. INTROWCTION The Central Alaska Power Association is interested in fur- nishing low cost power to its members in their market area and bring- ing this power to them over an integrated transmission grid system. The market area includes the Matanuska Valley, Greater Anchorage and its environs and the Kenai Peninsula from Seward to Homer. From previous reports of varioas hydro sites throughout the area, the Cooper Lake Project has been selected by The Central Alaska Power Association for detailed investigation with a view to supplying the first block of low cost hydro power to the entire area of its membership. 2. PREVIOUS INVESTIGATIONS Under Appendix "ff" of this report will be found a list of previoas reports on various hydro projects in the area. These re- ports cover several large river projects as well as several involv- ing high lakes on the Kenai Peninsula. Cooper Lake seems the most favorable site for :initial construction, both as regards size, con- struction and installation costs and cost of generated power. 3. POPULATION AND ECONOMIC TRENllS This subject is covered in Appendices "A" and IIC" and in- dications are that the subject area is-definitely in an era of ex- panding economy. The power supply of the past has been largely made up of scattered, high-cost thermal plants which has retarded economic expansion. Power demands are growing so rapidly that the Cooper Lake Project is e:xpected to be entirely loaded up within five years and other projects must be developed without delay. 4. DESCRIPTION OF PROJECT (a) Project Plan. The Cooper Lake hydro-electric Project consists of a 50- foot high earth dam to elevation 1200 t at the outlet of Cooper Lake to create storage; an intake structure 4 miles up the lake; a l-mile, 8-foot tunnel; about 2,075 feet of 5 19" diameter :x: 3/8" plate steel conduit; a steel surge tank and 2,450 feet of steel pipe penstock to the reinforced concrete powerhouse on Kenai Lake at elevation 436, giving a net head of about 734 feet. The prime power available is 4,750 KW continuous, and as the' system load factor is about 50%, the -1- F'OIlTL4NC) • ORltaON NOR T H PAC f F I ( ( D N ~ U l TAN T S AN4:~ORAac. AI,4.K4 - • • • • • • • • • • -.I - • - installation of at least 10,000 KW is war!"anted. and. preferably 12,000 h."W in two '!l1lits of 6,000 KW each. See Plates "A" and "Bn showing the lake and general character of the drainage basin end Cooper Creek with the location of the ~ (b) Climate. The climate consists of mild summers and rigorous winters with much of the precipitation in the form of snow, which runs off rapidly in June and July, inc:-easing the necessity for storage. Annual precipitation is about 50 inches. ( c) Run-off. The run-off from the 31.17 square mile drainage area is estimated tv yield 90 cfs for power Pll..""'Poses. Diversion of stetson Creek is recommended to add 20 cfs and Ptarmigan Creek to add 5 to 10 cfs for a total of 115 cfs. ( d) The Complet.e Development. The addition of these two supplemental areas will increase the pr:ime power output to 6,100 KW continuous and warrants the in- stallation of 15,000 KW capacity. Two 7,500 KW units are recommended. (e) Storage and Regulation. The lake run-ofi" varies from 12 cfs for three winter months to some 400 cfs more or less, during June and July. As a somewhat uniform draft all year around 1.:3 required to meet the power demand, it is necessary" to provide ample storage to smooth out the flow. Cooper Lake is ideal ~ this regard in that its area, 2,150 acres, is 10+% of that of the entire dra:inage basin. It is necessary" to raise the lake only 24 feet to secure the 58,000 acre-feet required to regulate Cooper Lake discharge alone. By raising the lake 32 feet, it is possible to secure 82,000 acre-feet which is sufficient to regulate the additional flow from Stetson and Ptarmigan Creeks. The storage provided will regulate the rtm-off completely and spill should seldom, if ever, occur. Water will be available to meet the power draft at all t:imes. (f) Diversion of Stetson Creek. Stetson Creek joins Cooper Creek about a mile downstream from the lake outlet. It has a steep gradient and may be readily diverted into Cooper Lake by a low di'Version dam and 1-1/2 miles of open canal. The benefits from this additional water supply are estimated to exceed the cost by more than three to one. ( g) Fish and Wildlife z Land Use and Natural Resources. Cooper Lake is a natura.l lake in an isolated valley entirely' -2- POATL. ... .,O ORlEaON N n D'T U P'& r 11= I r r n N c: III T.& NT.C: A .. e"o ..... cl:. AUSKA - - - • • • • .. - • --, • - - devoid of cultural developments. Cooper Creek's gradient is so steep that salmon can not gain access to the lake but some enter the lower mile of the stream for spawning. Diversion of Cooper Lake and' Stet- son Creek for power will greatly reduce the flood peaks in Cooper Creek. The area below the dams contribute sufficient run-off to sus- tain the fish rmlS and spawn:mg grounds. Through the project, the area around Cooper Lake itself will be opened up for hunters, fishermen and tourists as game and fish are plentiful and the scenery is outstanding. (h) Construction Schedule. Construction of the project is simplified by the fact that the construction areas a:re spread out and can be scheduled sequenti- ally. The tunnel operation can be carried forward during the winter, thus gaining valuable time. While the equipment is being manufac- tured, the powerhouse can be -Constructed. One full season should be sufficient for construction of the small dam -and the entire project is estimated to require 2-1/2 years. See Plate "cn for the complete graphic schedule of construction, which assumes an immediate start to meet the estimated power requirements in 1958. 5. GEOLOGIC CONDITIONS (a) Dam Site. The dam site at the outlet of Cooper Lake is extremely fav- orable in that; it is small; has impervious foundations; and has ex- cellent rock in the left abutment for a spillway. This rock is a durable slate, very common in the area. The foundation under the remainder of the earth dam is a compacted glacial till with sufficient fines to make it practically impervious --especially at such a low head as will e:x:i.st at the dam -some 60 feet maximum. The pervious layer of anconsolidated materials will be excavated over the area of the dam upon which the impervious compacted core will rest. (b) Tunnel. The tunnel will be entirely in rock of durable graywacke or slate. It is estimated that not more than 20% of the tunnel will require support and these portions, wherever encountered, will be lined with concrete, reinforced if necessary. (c) Conduit, Surge Tank and Penstock. The route selected for the conduit and penstock is under- lain by bedrock (graywacke and slates) at shallow depths and the pipe lines ~...ll be trenched into and anchored to the rock throughout. The steel surge tank will rise from the crest of the highest rock hill available and will be excavated into the solid rock. -3- F'ORTI..AND • OREGON NOR T H P A ( I F J( ( 0 N S U LT ANT S ANCHORAGE. ALASKA - -.. til til .. ,- .. .. - - .. -,J - (d) Powerhouse 0 The site for the po-werhouse was qarefully selected so as to have solid graywacke foundations. The solid rock is exposed over the entire powerhouse foundation and is ona of the outstanding ad- vantages of this layout. (e) Stetson Creek Diversion. The Stetson Creek channel is in solid rock and, can be diverted by a low dam. The canal will be through rock cut for the first ona hundred yards of ca.:ayon beyond which, it will be open canal located on the contour to bring the water into Cooper Lake for stor- age, regulation and use for power. 6. PROJECT PLAN (a) Dam. The dam. will be earth and rock fill with spillway over rock in the ,left abutment. The crest elevation will be at elevation 1202 for Cooper Lake alone or at 1210 for the ultimate project, with 10 feet of freeboard above maxim.um storage elevation in each case. (b) Reservoir. Cooper Lake will be raised 24 or 32 feet to create the reservoir required under the two plans recommended.. The reservoir is rock-botmd on both sides and one end.. The outlet at the dam. is closed off by the dam and impervious glacial till strata beyond the limits of the dam. The reservoir is large in relation to the flow and sufficient storage is readily attainable with a low dam. MOst remarkably, the IIheadll created by the dam. will practically compen- sate :£or the entire cost 0:£ the dam, as head has a capitalized power value of about $7,000 per foot • (c) Intake and Tunnel. The intake will be a rein:t'orced concrete structure founded on rock at the present lake level and extending 10 feet above pool level. There will be steel trash racks and a gate to control the flow into the tunnel. The tunnel will be about a mile long, through rock,. and 8 foot horseshoe shapeo Its size and capacit,r are somewhat greater than required but are dictated by most economic and feasible con- struction methods. A::r:r:r portions of the tmmel requiring support will'be concrete lined • -4- PORTLAND. OREGON NOR T H PAC I Fie CON S U L TAN T S ANCHORAGE. A1..ASKA ,,. - -.. • .. '~ .• .J . ., ' .... -,,.J -,.J (d) Ptarmigan Greek Pickup. The conduit crosses Ptarmigan Creek at elevation about 1000. It will prove ve::y profitable to set up a small pwnping plant there to pump Ptarmigan Greek water into the conduit. The average net gaiil in water should be from 5 cfs to 8 cfs and the net power gain should be approximately 1,500,000 KWH/yr • (e) Conduit and Surge Tank. From the tunnel a 5 r -9" steel pipe conduit will convey the water to, the surge tank. The conduit will be buried in a trench for protection from damage and freezing • The surge tank will be a 15 foot diameter steel tank ex- tending some 70 feet above ground elevation of 1140:. It will be protected by a wood covering, and warm air from electric space heaters will prevent freezing. (f) Penstock. The steel penstock will convey the water 2,450 feet from the sarge tank to the powerhouse turbines. The pipe diameter and thickness of plate var;r as the head increases. At the powerhouse there will be a steel plate wye with branches to each of the two tur- bines. The penstock will be. in trench, largely' in rock and anchored by heav.r concrete blocks at all slope changes and at intermediate points as-required. (g) Powerhouse. The powerhouse will be a reinforced concrete structure housing the two generating units, a work shop, control room, battery room and other facilities. There will be a 25 ton overhead crane for erection and maintenance purposes. The tailrace will discharge di- rectly" into Kenai Lake at elevation 436: • (h) Turbines and Generators. There will be two Francis, vertical type turbines with a butterfly valve directly" in front of them to shut off the water for emergency or repair.. They" will be operating at a speed of 900 rpm under a head of about 750 feet and develop 8,400 R.P. each. The generators will produce 6,000 ~N at 0.80 P.F., 4,160 volt, turning at 900 rpm. ( i) Controls .. The controls for the plant will be automatic with super- visory control from Anchorage. -5- ANCHORAGE. ALASKA . -PORTLANO • OReGON N 0 RT H P A CJ F I ( ( 0 N S U L TA N T S • • • • • • • • • • •• • j . "" • • 7. HYDROELECTRIC POWER (a) Market Area and Characteristics. The market area comprises the Matanuska Valley, Greater Anchorage and environs and the Kenai Peninsula area from Seward to Homer. The peak demand at present is over 30,000 KW and it is es- timated, will exceed 70,000 KW within 10 years. The average annual load factor of the area is about 50%. (b) Available from Project. Cooper Lake Project will have a peaking capacity of 12,000 IDf and produce a total of 41,500,000 KtVH at the site. The ult:i:aiate project would have an installed capacity of 15,000 KW and produce 53,000,000 miff annually. (c) Correlation of Generation and Use. The annual load factor is about 50%, the monthly load factor about 83% and the daily load factor 60% to 70%. Power from Cooper Lake Project can be made available at any time to meet the system requirements (within its capacity) because complete control of its water supply through reservoir storage makes its peak capacity available at any time and provides regulation throughout the entire year. (d) Estimated Worth at Plant. With a capacity of 12,000 KW valued at one dollar per kilowatt per month, the capacity value of the project is $144,000 per year. Annual production of 41,500,000 KWH is valued at 7 mills per KWH ::I $290,500 -or a total sum of $434,500 per year. Capital~ ized at 6%, this represents a worth of $7,240,000t • 8. ESTIMATED COST OF PROJECT (a) Project Plan. The estimated cost of Cooper Lake Project (Plan lrA_21t) with 2 -6,000 roN units is $4,990,734. (b) The estimated cost of the ultimate completed project including Stetson Creek and Ptarmigan diversions and consisting of 2 -7,500 roN units is $5,699,165 • -6- PORTLAND. OREOON N n R T H PAC I Fie CON ~ U I TAN T 5 ANCHORAOE. ALASKA • /' :. •• , .. •• ,., f i 1. .. f Lf l'" -L..; • 9. FEASIBJLITY The cost o.f additional capacity at the Cooper Lake Project is very low --about $110/~~ o.f incremental peaking capacity which is about 1/3 to 1/4 o.f the capital costs .for existing or planned thermal plants at load centers. The overall cost o.f energy at the site is estimated to be 1/2 to 1/3 o.f the cost o.f thermal energy at load centers. Summary o.f estimated power costs at the plant .for the project can be .found in Appendix "WI, Paragraph "E". The overall cost o.f power .for the recommended projects are: (1) Without Stetson Creek, Plan ItA_2" OVerall Cost Or allowing $l.OO/KW/mo • .for • • • 7 • 22 mills/l{ftJH Capacity Credit. 3.75 mills/KWH (2) Including stetson Creek - Plan "B-2" • • • • 6.45 mills/Kt'ffi Or allowing $l.OO/10d/mo • .for Capacity Credit. 3.05 mills/KWH 10. CONCLUSIONS (a) The Cooper Lake Hydro-Electric Project is a very .favor- able project. Its size and cost .fit the present economic situation. Its location will be in the center o.f the .future grid s,rstem. Its large storage capacity at low cost, the short tunnel, conduit and penstock and its high head all contribute towards low cost. The excellent rock foundations throughout provide safety of all structures. (b) The economic gains to accrue from the recommended di- versions of Stetson Creek and Ptarmigan Creek warrant ~heir inclusion in the overall project plan. (c) The load growth in the market area warrants the de- velopment o.f additional capacity and energy-immediately. 11. RECOMMENDATIONS It is recommended that the Cooper Lake Project be approved for immediate development • -7- POFlTI.. ... ND • OREGON PAC I Fie CON S U L TAN TS ANCHOR ... GE, A ...... SKA - • • • • • • . , • , • ; - • - - - The ultimate project including Stetson Creek is the most favorable and is recommended for adoption (Plan "B-2", Appendix "M"). This' project Will produce 15,000 KW at 40% plaJit factor and 53,000,000 KWH of energy at the site. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. PERTINENT DATA Recommended Plans of Development "A-2" and "B-2" Location -Kenai Peninsula, Alaska Distance from Anchorage -By Highway - By 'Air Drainage Area - AImual Run-off (1950-1955) - Elevation of Cooper Lake - Area of Cooper Lake - Reservoir Capacity - Spillway Lip Elevation - Spillway Capacity - Spillway Excavated in Solid Rock - Spillway Gates - Dam -Earth Fill with Impervious Core Dam Height - Tunnel -81 Horseshoe Section, in Rock throughout. Tunnel Length - Tunnel Lining -30% of Distance (Est.) 105 miles 55 n 31.17 Sq. Mi. 64,250 Acre Ft. 1,168 2, 1501: Acres 58,000 Acre Ft.* or 82,000 Acre Ft.**. or 1,192 MSL* 1,200 MSL** None 25,000 Cu. Yds.* or 58,000 Cu. Yds.** 42* or 50 Ft.** 5,650 Ft. 17. Conduit -6 1 Diam., 3/8" Plate (Steel Pipe) -8- POR ORltOON T PAr I Fir r n N <; III TAN T.~ ""N.C:~O"""L ALASKA - .. • • - • • • • -" 1" .. - 18. Conduit Length -2,073 Ft. 19. Surge Tank -15 r Diam. x 90' Hip or 100' Higb** -steel Tank, Insulated 20. Penstock -5075 r x 3/811 plate to 4.75. X 7/811 pla'te* or -6.0' x 3/811 plate to 5.5 ~ x 1" plate**- 21. Penstock Length -2,455 Ft. 22. Powerhouse -Reinforced Concrete 55' x 63' x 44 r High 23. Crane-25 Ton 24. Turbines -2-Francis type 8400 H.P. Vertical units, 900 rpnt:* 900 "** or -2-II II 10,500 H.P. II It 25. Generators -2-6,000 KW., 0.80 P.F. Vertical units, 900 rpmlE' 900 It ** or -2-7,500 KW.," tI It II 26 0 Generator Voltage - 27. Average Gross Head - 28. Friction Losses - 290 Average Net Head - 30. Pr:ime K.Wo Capability - 31. Annual Production - 32. Construction T:ime Required - 4,160 745.5 Ft.*' or 749.5 Ft.**, 11 Ft. to 26.6 Ft. 734 Ft.! 4,750 KW* or 6,100 K'fr1** 4r~ 500 , 000 KWHlfo or 53,000,000 ~ 2t Years *' The recommended plan o£ development (Plan "A-2 ft ) "Which does not make allowance for the diversion of flow from Stetson Creek. ** The recommended plan of development (Plan "B-2!') if Stetson Creek flow is to be diverted either for the immediate construction program or to be added at some future date as the u1tfmate development. -9- PORT~AND • OREGON N n R T H P A ( I F I ( ( n N ~ U I TAN T. ~ AfjC;:HORAGE. A ..... SKA .. . / " .. • • • • • .. .. - .. • • - Photo No. 3.5 Cooper La:';:e as seen from the Damsite Area. August 10, 19.5.5 NORT? ?ACI?IC CO;~S1.JLT1u'\TS Plate .~ - -.. .. • • • • • • -- -.. - - - , , ,·r· Photo No. 3 .. ' .. ,_;1< .. J ...... L_!: :~ ..,. -.... "~i,... .. -, Aerial oblique of Cooper Creek Valley from Cooper Lake to Kenai River. Da~s1te Area in central foreground. Note incision of present Cooper Creek Canyon below glaciated U-shaped profile. Kenai River flows from I·ig..~t to left in background valley. July 25, 1955 NOR'IE PACIFIC CO!\'SULTAN'IS Plate B I I • • • • , • • • • i "-,. • , , , • • I COOPE Q LA J<E Dt20JEC T PLANNING (: CONSTI2UCTION TIME ..5CHEDUL£ CONTRACT ITEMS 1956 1957 1958 V F M A W IJ J AS 0 IN D J F M A M J J A j 0 IN ~ J IF M A M J IJ A .5 0 N D ACCe:55 raci /itirz.:J B ). J20ads { Docks c --'-----I---f------~ --'--------.-I----------~-----~----. ('t"'2/, J n fa krz fj j ~ ~ r-~ k-I-'91 ~J' 0 IV. 171: !r/( Dn t. f>fi h, In.h Wafer Diver~ion ..... rt ,-£ ~ '1 '..I) IIr Ie? If ----'-.~---'---- () ./:, ~~ Darn ~ Ie j.... I fA .1 15. It. \,t::; ~r. V~ ttl Iryc '1/ [(r rUi IS fl 0 .N t ~ -----_ .. _--I---.. ~ ---~ -----~ ---I---1--. /-. --I--------:~ Cond('/I'~ Pflns/vck \.: J ,r. 0 r.l;, ~ _ {~t::!:.!i~_~~~_ f c ~ $ ~ '---I---. f---1-----_. -+----r;bme:J &nvralvr~ 5 ~ 4 (: MC'Jor Egvipmqnf . ( ~" :::J/ ~n II (j ~ 'rn y-"4 '(:1 VI crlJ (J {1 ~1c 'h . ---~..---------I--. A --'-----1 7 ~~ rJ t. POIVf2rhoustZ (r- .---IfFF --f---f-----~ f----f- stf2tson I P/arml9an ~t> .!~ kB (~ C/lZ(lK O;~rsion.:J -~--,---a= l?iiz/im~naIYo A == F;~ Id Invrzsti9.9lions and .5urvQCjs InVtZ:1/tlCJ '0171 b' :::t:rCl ~on 0 I 8 = Prqparafion ot Plan.7 and Spt1cifiOfifion5 ~u lInla/ DPI2 C =. AWc!Jrd 01' Control cYnd Con:slruct/or) al'F'/. -for l/c~n.5fl Norfh fJacit/c Consulfanfs '---- - • • • • • • • • .. • - -- - - - APPENDICES IIA!! ~ HISTORICAL "BII. NATURAL RESOURCES "Clf 0 ECONOMIC DEVELOPHE1"T IfDI! • TOPOGRAPHIC FEATURES PORTL ... NO • OREClON N 0 RT H PAC I F IC ( 0 N S U l TA N T S ANCHOR"'Cl~ AL ... SK ... - - ,. • • • • • • • ,. - - - - - CONTENTS Appendices "At!, nBn, IICII and ltD" Appendix flA" History and Settlement A. Historical- B.. Population - - Appendix "B" Natural Resources C. Resources - -- 1. Minerals - 2 .. Forests - 30 Agriculture 4 .. Fish -- ---5. Recreation - Appendix tlCI! Economic Development Do E. F. G. H. General - - - - Transportation - Land Use - - Forest - - Minerals - Appendix liD" Topographic Features I. Topography - - - ----------- ---------------- ----- ---- J. Transmission Network ----. PORT!..AND. OREGON NOR T H P At I Fie CON S U L TA N IS ANCHORAGE. A!..ASKA A-1 A-1 A-4 A-4 A-5 A-5 A-5 A-6 A-6 A-8 A-IO A-13 A-13 A-14 A-15 - ., .. • • • • • • • • • - .. • - - APPENDIX A 0 HISTORY AND SETTLErlENT A. HISTORICAL The Kenai Peninsula-Greater Anchorage area, together with the lower sections of the Matanuska Valley, comprise the territory to be served by the proposed Generation and Transmission pool of the Central Alaska Power Association. This total area includes the communities -- villages and cities --of Homer, Anchor Point, Clam Gulch, Ninilchik, Kasilof, Kenai, Hope, Cooper Landing, Seward, Moose Pass, Lawing, Portage, Girdwood, Anchorage and its metropolitan area, Eklutna, Park- sville, Chugiak, Palmer ... Matanuska, Jonesville and Wassila, as well as large military installations such as Fort Richardson, Elmendorf Air- base and others. Settlement of this vast area began in 1788 by Russian colon- ists at Kasilof, Kenai, and in the Kachemak Bay area. However, it was only in the 1880 l s that considerable activity in gold mining and salmon fishing began to bring population into the area. In 1903, the construction of a railroad from Seward to the Matanuska coal fields was started, but ended in failure. In 1914, the Federal government began construction of what now is the Alaska Railroad. Anchorage was founded at that time with the establishment of a tent city for the railroad construction crews. In 1935, the famous Matanuska Valley colony was established by the Federal Government in the fertile valley some fifty miles northeast of Anchorage. The defense preparations of the late 1930's catapulted the area into military prominence. Tre- mendous bases were constructed, resulting in a heavy and continuing infl1L~ of construction workers and managerial staffs. During the past two and a half decades, the area has stead- ily grown in economic and military importance. Population has risen sharply, and in spite of the reaching of a plateau in defense expen- ditures, continues to grow. B. POPULATION The following table lists the population of the area and its major communities for a number of past Census years. A-I PORTL.ANO • OREGON N 0 RT H P At I F IC CON S U l TA N T S ANCHORAGE. AL.ASKA - - • .. • .. .. .. • .. .. -.. - -.. - - POPULATION OF KENAI PENINSULA, ANCHORAGE AND 1,fA.TANUSKA VALLEY AREA 11 (Source: U. S. Department of Commerce, Bureau of the Census: 111950 Population -Alaskan "Report P-A51, 1952") Co~~ity and Area Anchorage Area: Y Anchorage City Artesian village Eastchester village Eklutna village Girdwood village Kasilof village Kenai village Mountain View village Portage village Spenarc. village Woodland Park village Homer District: Anchor Point village Homer village Ninilchik village Palmer District: Eska village Jonesville village Matanuska village PaL-ner village Seward District: Cooper Landing village Hope village Moose Pass village Seward Wasilla District: Wasilla village 1950 32,060 11,254 381 3,096 53 79 62 321 2,108 34 2,,880 94 907 65 307 97 2,523 54 97 41 890 2,708 60 63 70 2,,114 585 97 1939 4,229 3,495 159 62 303 20 325 132 1,441 52 150 1,525 71 84 940 548 96 1929 2,736 2,277 158 45 286 124 1,279 15 835 460 51 11 Includes persons in the armed forces quartered on military instal- lations. Y Includes small communities such as Tyonek and Skwentna villages (total 1950 population of 190) on north shore of Cook Inlet o A-2 PORTLAND. OREGON NOR T H PAC I F J ceo N S U l TAN T S ANCHORAGE. ALASKA - - • • • • • • • • • .. .. • - - The foregoing table indicates that the area under considera- tion, in 1950, had a population somewhat in excess of 38,000. However, since 1950 there are indications that present population has risen sharply. The Anchorage Chamber of Commerce, in 1955, for instance, estimates that 95,000 persons reside in the Greater Anchorage area it- self, of which 60,000 are civilians and 35,000 military personnel. That this estL~ate is reasonable can also be measured by the fact that the UoSo Census Bureau estimates Alaska's civilian population for 1955 at 168,000, an increase of 60,000 since the 1950 Census. Most of this increase can be considered as having taken place in the Anchorage area. Another factor which sustains this estimate is the present "tight" status of housing in Anchorage in spite of substantial increases in housing unitso In addition, bank deposits and total business receipts have continued to increase substantially. The total number of persons in the working force in Anchorage is also stated to have risen con- sistentlyo Inasmuch as a part of the population is composed of persons in the armed forces, it is appropriate to comment on this fact. Obvi- ously, the strength of the military in the area under consideration is a "classified" item. It appears entirely proper, however, to consider this portion of the population as likely to remain fairly stable for a number of years, because the strategic defense position of this sec- tion of Alaska particularly, is unquestionably pre-eminent. The forecasting of population trends for the area cannot be limited to a consideration of past trends excrlusively. This is due to the fact that there is occurring a shift in the economic foundation of the area away from predominantly defense construction activity to a more diverse and more stable base. This will be particularly the case as electric power supplies from such sources as the Cooper Lake Project and others come into being and make possible th~ wider use of electric power for agricultural, industrial, and commercial activity. The trend of civilian population in the Territory, based on statistics of the U.S. Bureau of the Census, the Alaska Resources De- velopment Board, and the Bureau of Vital Statistics of the Alaska De- partment of Health, has shown an increase averaging approximately 8,000 persons per year during the period 1945-1954, and can be esti- mated at 10,000 per year during the extended period 1950-1960. This estimated future rate is equivalent to compound rates of annual in- crease ranging between 6i% & 7!%. (The annual compound rate for the ~-lestern States of Oregon, Washington, and California from 1940 to 1950 was 4%)0 It is pointed out in the following section on "Economic Developments" that economic developments in the Kenai Peninsula- Anchorage-Natanuska Valley area are likely to increase substantially. These developments will be accompanied by increasingly stable and rising employment, and hence population growth. Therefore, for the purposes of this report, it is considered realistically conservative A-3 PORTL. ... NO • OREGON N 0 RT H P A ( I F I ( ( 0 N S U L TA N T S ANCHOR ... GE. AL. ... SKA - • • • • • • • • • • .. -- - - - - to use a rate of at least 6% compounded annually for the growth of population in the area. The resulting range of population estimates for the area can be seen below: Estimated Population Projections for Kenai Peninsula- Anchorage-Ha tanuska Valley Area 1955 1965 1975 Civili~~ and Military Population at 6% 100,000 179,000 321,000 Civilian Population at 6% -Military Stable 100.000 142:000 227,000 APPENDIX B 0 NATURAL RESOURCES C. RESOURCES Description of the natural resources of the Kenai Peninsula- Anchorage-Matanuska Valley area is made difficult because of the lack of accurate and adequate information. Certain sections have been in- tensively studied but, by and large, the area remains unknown as to its inventory of possible mineral occurrences, the type and character of its soils, and the volume of timber species. 1. Minerals. It is believed that the entire area is well mineralized. However, emphasis of commercial mining --reflecting traditional int- erest --has been for gold, coal and, more recently, for chromite. Reference to the geological literature on the area reveals the exist- ence of at least the following: chromite, clay, coal, copper, gold, granite, gravel, gypsum, lead, limestone, molybdenum, platinum, pumice, sandstone, tungsten • In terms of present ITIJ.1ll.ng activity, coal and chromite are most important. The Matanuska coal fields continue to be the major source of coal for the Anchorage area, being utilized primarily for ste~raising and power production. Other coal fields include those in the Homer area at the southern end of Kenai Peninsula. The major portion of these coals rank from bituminous to sub-bituminous. with some anthraciteso The Evans Jones coal mining operations near Palmer in the Hatanuska Valley are the principal ones in this industry. Across Kachemak Bay, from Homer, in the Seldovia district, are extensive deposite of chromite. These have been known and recog- nized for a number of years as the only important source of metallur- gical nlump" chromite available to the United States within its own confines. During the past two years, an active mining operation has A-4 PORTLAND, OREGON NOR T H P At I Fie CON S U L TA N T S ANCHORAGE, ALASKA - .. • • • • • .. • .. -.. .. - • - - been shipping high-grade ore for goverr~ent stockpile purposes. It is reliably estL~ated that a very sUbstantial quantity of lower-grade ore exists in the area. Also in Kachemak Bay are limestones known to have some Luportant extent. Recent unofficial reports indicate possibili- ties of massive quartzite. Of great potential importance to the en~~e area are oil and gas-bearL~ stra~a. These are being explored vigorously by major oil companies. 2. Forests .. Forest resources of the area are partially in the Chugach National Forest and the remainder in public lands under the U.S. Bur- eau of Land Management. In the extreme southern tip of the Kenai Peninsula on Kachemak Bay in the Seldovia area are stands of hemlock and spruce. These species are also found in the Chugach range low- lands from Skilak Lake northward to Turnagain Arm and eastward to Prince William Sound. Some hemlock and spruce are also found along the northeastern shore of Turnagain Arm. In the Anchorage and Matanuska Valley area, the predominant species are white birch, white spruce, balsam poplar jl aspen and cottonwood. The wet lowlands of the entire area contain black spruce • Of greatest commercial interest are the hemlocks and spruce of the Kenai Peninsula, and the spruce-birch stands of the Anchorage- }1atanuska-Susitna valley areas. Present utilization is in small saw- mills scattered in various parts of the entire area in proximity to population centers. 3. Agriculture. The agricultural lands of the area are believed to be the most important of the entire Terri tory. These occur in three princi- pal areas: along the west coast of Kenai Peninsula, the Matanuska Valley, and the Susitna Valley. Soil surveys and land classifications are rather limited in extent except for the Matanuska valley. The U. S. Soil Conservation Service estimates the Matanuska valley contains about 59,000 acres of potential crop land and 153,000 acres suitable for grazing. On the Kenai Peninsula, the Servic e estimates 155,000 acres may be suitable for crops and 132,000 acres for grazing and pasture. The Susitna valley, immedi.ately adjacent to Anchorage across Knik Arm and Cook Inlet: has not been surveyed for land types but the U.S. Bureau of Rec1am4tion believes 96,000 acres are potentially suit- able for agriculture. 4. Fish. Fish resources have and continue to be important to the economy of the Kenai Peninsuia-l'.nchorage-Matanuska Valley area" The salmon fisheries on the Cook Inlet and Prince William Sound are among the area's most important economic activities. AJl'long the predominant A-5 PORTLAND. OREGON NOR T H P At I F I ( ( 0 N S U L TA N T S ANCHORAGE, ALASKA - -.. • • • • • • .. .. • • .. .. .. - .. and most important species are red, king, cohoe, pink and chum salmon; halibut; herring; cod; clru~s; shrimp and more recently Alaska King crab. Sports fishing for salmon and trout represents an important con- tribution to the economy of the area • 5. Recreation. The incomparable scenic resources of the area are beginning to be recognized as the important foundation for a major resort and tourist industry. In combination with such outdoor sports as fishing, big game and bird hunting, hiking and mountain climbing, skiing and dog sledding, the magnificent vistas of mountain, glacier, fresh and salt water bodies cannot be surpassed anywhere in the world. APPENDIX C. ECONOMIC DEVELOPNENT D. GENERAL· The overall area of the Kenai Peninsula-Anchorage-Matanuska Valley presents an homogeneous economic unit with its parts mutually interdependent. This results from a combination of phYSiographic, climatic, transportation, and resources factorso The major portion of the Territory's population and economic activity is centered in this area o From its inception as a "tent" city for construction work- ers on the Alaska Railroad, Anchorage has grown to be the hub of economic activity for the Kenai Peninsula and adjoining areas. An appraisal of the future of the entire area indicates that Greater Anchorage and environs will continue to grow at a significant rateo Development of Seward, Homer and intervening communities '-Till depend primarily upon the utilization of the resources in their vicinityo Seward and Homer particularly will benefit from deep-water transpor- tation, and it can be forecast that economic activity in these commu- nities will increaseo The area, as a whole, contributes the major portion of the Territory1s business economic life. Statistics are rather sketchy and incomplete in view of the dynamic growth taking place particularly in the Kenai Peninsula-Greater Anchorage-Hatanuska Valley area o Ac- cording to the U .. S .. Department of Commerce IICounty Business Patterns - First Quarter 1953" ~ the follow"ing percentage breakdown is indicative of the relative position of this area to the Territory as a whole: A-6 PORTI. ... ND • OREGON N 0 RT H PAC I F Ie (0 N S U l TAN T 5 ANCHOR ... GE. AI. ... SK ... .. -.. .. .. .. .. .. • .. - - -- - - 1953 -Payroll Percentage (Number of Employees, !'rid-March Pay Period) Third Judicial District to Entire TerritoI'"lJ (Under Old-Age and Survivors Insurance Progra.-rn) Item Mining Contract Construction Manufacturing Public Utilities Wholesale trade Retail trade Finance, insurance, real estate Services Percentage 22 0 6% 43 .. 2 30 0 4 65 .. 1 46.6 49 .. 4 42.6 48.2 (Note: The above under-states the situation inasmuch as peak activities in the area occur at a later date than :rvIid-March) Another evidence of the predominance of the area in the overall economic position of the Territory is reflected by an analysis of the assessed valuation (real and personal property) of incorporated towns and cities of Alaska. These data are from the Alaska Resources Development Board IIFinancial Data Regarding the Incorporated Towns and Cities of Alaska, 1954" issued July 1955: 1954 -Percentage of Total Assessed Valuations for Alaska Amount (Hillion dollars) Percentage Total for Alaska $220 100 .. 0 Anchorage $ 87 39.5 Palmer 5 2.3 Seward 8 -306 Sub-area Total $100 4505% During the period 1949-1954 (from the same report of the Alaska Resources Development Board), the area's position regarding the issuance and value of building permits by the same incorporated cities and tovms of Alaska is shown as follows: A-7 PORTLAND, OREGON NOR T H PAC I F I ( ( 0 N S U l TA N IS ANCHORAOIl. ALASKA .. - • • • • .. .. .. .. .. Percenta e of Number a..'1d Value of BuildL."1. Permits Issued bv the Incorporated Cities and Towns of Alaska 19 9 -1954 Value No. of (Million Per- Permits Percentage dollars) :::entag~ Total for Alaska 5,333 100.0% $72 100.0% Anchorage 2,556 48.0 32.374 45.0 Palmer 3 0.1 0.037 0.2 Seward 344 6.4 2.736 30 8 Sub-area total 2,903 54.5% $35.147 49.0% Numerous reports have been issued reviewing the economic base of the area, and pointing to its growing commercial and service industry. 11 Each year shows-important additions to this industry, and the com- mercial establishments in Anchorage are as modern as any in Stateside communities. The utilization of electric power in these establish~ents is growing very rapidly through the use of extensive modern lightii~, and modern business equipment. The pattern of development is similar to that taking place in like establishments in the States; it is cer- tain that greater use of electricity per establishment is sure to fol- low expansion of generation capacity and reduction of power cost. E. TRANSPORTATION All forms of transportatior.. are available ir: the area and converge at Anchorage. The Alaska Railroad --a modern facility now completely dieselized --crosses the waist of the Kenai Peninsula £rom the year- round, ice-free ports of Seward and Whittier, the latter of which is strictly a military installation. At present, ocean-borne cargo is discharged at both of these terminii for rail transportation to vari- ous "Railbel t" points along the Kenai Peninsula route to Anchorage, thence to the Natanuska Valley at Palmer and northward into Fairbanks. Trucking companies handle ocean-borne cargo to and from Seward and the Port of Valdez and overland via the Alaska Highway. Seatrain operations are expected to begin in the near future from Seattle to Seward and Whittier with "roll-off" operations to the Alaska Railroad. The two principal companies engaged in Alaskan ocean transport are the Alaska Steamship Company and the Coastwise Line. At 11 Such reports include those of the Alaska Development Board, "Anchorage -An Analysis of Its Growth and Future Possibilities", Decerr.ber 1953 A-8 POFlTL. ..... C , ORo;GON NO RT H P At If ICC 0 N S U l TA N T S ANCHORAGE, AL.ASKA -.. • • • '. • • .. • • .. - - .. .. - - present, deep-draft ocean navigation to Anchorage itself is somewhat limited. However, the City of Anchorage has begun engineering and economic studies for the establishment of a modern port facility on upper Cook Inlet. The city has passed a $2 million bond issue to support the proposed construction and is now considering another $1.5 million dollar issue for the same purpose. When constructed~ this proposed $8.5 million facility will make feasible direct shipments of ocean-borne cargoes directly into and from Anchorage for at least 8 months of the year. Substan~ial savings in overall freight charges will accrue to the Railbelt area and possibilities of return hauls by direct ocean shipping will be substantially enhanced. There is also under preliminary consideration the establishment of a major causeway structure across Knik Arm at Anchorage. Among its antici- pated benefits can be included a reduction of navigational hazards caused by ve~J high tidal currents and ice movement during winter months. The causeway may make possible the operation of the pro- posed port for twelve months of the yearo Highway and road systems serve most of the area under con- sideration. From Seward to Anchorage, a modern, paved highway tra- verses the Kenai Peninsula for some 140 miles, serving Moose Pass, Lawing, Portage and Girdwood. From Homer, at the western extremity of the Kenai Peninsula, the Sterling Highway --a good gravel road soon to be hard-surfaced and approximately 130 miles long --follows the western shore of the Peninsula along Cook Inlet providing access to the communities of that area including Ninilchik, Cohoe, Kasilof, Kenai, Soldotna, and Cooper Landing. It joins the Seward Highway about 13 miles from Cooper Landing. The highway at and eastward of Cooper Landing, skirts Kenai Lake at which the proposed Cooper Lake Project's power plant is to be located. At Cooper Landing, the High- way crosses Cooper Creek, which is the outlet of Cooper Lake. The proposed power project is therefore readily accessible to the ~~jor highways of the area. (Also, the Alaska Railroad passes through Lawing on the eastern end of Kenai Lake o This makes possible move- ments of heavy freight via Lawing by barge on Kenai Lake to the proposed power plant site.) At Anchorage, a sizeable network of local roads and highways serve all the outskirts and the suburbs of that City • Leading northeast from Anchorage, the Glenn Highway reaches the Mata- nuska Valley at Palmer, less than fifty miles distant. At Palmer, a road system serves the area of the lower Susitna Basin. The Glenn Highway, modern and hard-surfaced, continues in an easterly direction for 189 miles from Anchorage to intersect the Richardson Highway at Glenallen. The latter highway serves Valdez 116 miles to the south on Prince William Sound and continues northward from Glenallen for 152 miles to Delta Junction and another 97 miles to Fairbankso At Delta Junction, the Richardson Highway intersects the Alaska Highway. This latter highway is also reached by a more direct route from Glenallen on the extension of the Glenn Highway for 135 miles to Tok Junction. Airplane transportation is highly developed in the Terri- tory and Anchorage is considered the hub for this facility. At the A-9 PORTLAND. OREGON N 0 RT H PAC I F I ( ( 0 N S U l TA N T S ANCHORAGE. ALASKA - - • • .. .. .. .. • .. .. - - • • - - Anchorage International Airport, fourth largest in the United states and its Territories for traffic, major airlines serve the area both from Stateside points and within Alaska. These include Pacific North- ern Airlines, Alaska Airlines, Northwest Airlines, Northern Consoli- dated Airlines, Reeve Aleutian Airways, and Cordova Air Service. Scandinavian Airlines has selected Anchorage as its midway point for transpolar flights between Europe and Japan. Numerous airplane- charter services are available in the area, and private plane owner- ship per capita is probably the greatest in the world • F. LAND USE Agricultural utilization of the lands of the area under con- sideration was started on a very small scale by Russian colonists in the Kachemak Bay area in 1793. However, it was in 1935, through the efforts of the Federal government at Matanuska, that agricultural de- velopments were given significant impetus. At present, farming of a diversified nature is carried out in the Matanuska Valley, in the immediate environs of Anchorage, and in various parts of the Kenai Peninsula, especially in the Homer-Ninilchik-Kenai sections. The out- put of this industry is consumed locally although a minor portion finds its way into stateside specialty markets. The principal vege- table crops successfully raised are varied and include=-potatoes, beets, carrots, turnips, rutabagas, onions, radishes, cabbage, celery, lettuce, cauliflower, broccoli, green peas, and rhubarb. Dairying has developed to be the most important farming activity in the area, particularly in the Matanuska Valley D As a measure of overall farm- ing and land use, the following tabulations summarize the situation as of 1954 • Acreage in Specified Crops. Total Cropland and Acres Cleared 1954 Kenai Peninsula -_~chorage -Matanuska Valley Area (Source: Alaska Agricultural Experiment Station and Alaska Department of Agriculture) Kind Potatoes Vegetables Other crops and idle Total cropland Acres cleared in 1954 Matanuska Valley 560 185 8,070 8,815' 445 Anchorage Area 85 30 635 750 90 A-1O Kenai Peninsula 25 20 680 725 150 Area Total 670 232 9,385 10,287 685 % Alaska Total 58% 76 80 78 66 PORTLAND. OREGON NOR T H P A ( r F I ( (0 N S U l TAN T S ANCHORAGE. AL.ASKA - - - • • • • .. • • -.. - -.. - - Agricultural Production, 1954 Kenai Peninsula -Anchorage -Matanuska Valley Area (Source: Alaska Agricultural Experiment Station and Alaska Department of Agriculture) Farm Income and Value of Produc- tion -Dollars Dairy products Livestock:Beef Pork Lamb Wool Poultry:. Eggs Meat Vegetables: Potatoes Cabbage Lettuce Carrots Other Total value Com- mercial produc- Matanuska Anchorage Kenai Area % Alaska Valley Area Peninsula Total Total $837,664 24,036 300 56 135,550 12,825 321,725 18,298 46,515 26,900 33,080 $ 26,985 1,000 26,600 33,000 32,000 67,780 8,100 1,335 1,662 8.467 $ 64,777 $ 929,406 7,685 32,721 240 27,140 60,000 2,590 15,600 218,930 47,415 405,105 26,398 47,840 28,562 5,015 __ 4;;:;.o60..J025:;..;;6;..=,2 74% 57 94 63 75 66 68 83 86 67 tion $1,456,929 $206,909 $155,907 $1,819,743 70% From these tabulations, it can be readily observed that the Kenai Peninsula-Anchorage-Matanuska Valley area contains the major portion of agricultural activity in the entire Territory. This is due to a combination of controlling factors: suitability of soil types, climatic conditions and nearby consumptive markets. The availability of lands of a suitable type for agriculture far exceeds the amounts 'now utilized. However, each year additional land is brought under cultivation, and new and expanded farm acreage adds its contributions to overall agricultural production. Even with this expanded production, however, a very large proportion of the re- quirements of the population for foodstuffs is imported by ocean ves- sel and by plane from the Pacific Northwest and neighboring states to supplement insufficient local sources of supply. For example, accord- ing to studies ~~de in 1953 by the Alaska Experiment station at Palmer, the total production of fluid milk in 1953 was only about 27% of po- tential demand in that entire area. In other types of farm products, the percentage contribution to total potential demand is even much lower • A-ll PORTLAND. OREGON NOR T H P A ( I F I ( (0 N S U l TAN T S ANCHORAGE. ALASKA - .. • .. • .. .. III • • • .. .. - - - - The reasons for the definite imbalance existing between farm production and potential con~~tion of the local population of the area are complex. Soil types and climate, of course, restrict the production of many items. On the other hand, constant research by the Alaska Experiment Station and others is leading the way to the devel- opment of plant species and strains which will be adaptable to the peculiar conditions of the area. However, other factors have served to inhibit a much greater expansion of agriculture. These factors act in compounding manner and include such as the high cost of clearing new land, buildings, agricultural implements, storage and processing plants, feed supplements for livestock and the like. Due to heavy past demands for construction labor at very high wages, farm labor has been virtually non-existent so that the vast majority of farms are strictly family-owned and operated. New ways of cutting costs, increasing ag- ricultural production per unit of farm land, bettering the quality of product, facilitating marketing and financing --in effect, doing a better job in agriculture in the area -are under constant discus~ sion, trial and adaptation. In this respect, the availability of electric power has and will playa very important part. Rural electrification is becoming well established in the Matanuska, Anchorage and Kenai Peninsula areas. Rural power lines are being extended further and further into areas not yet served. The average farm of the area is becoming as modern as its counterpart in the 48 States, thanks to the utilization of electricity. This is particularly important due to the very high cost of labor and its limited availability. The farmers of the area must use electricity in every aspect of farm management to increase produc- tivity at the lowest labor cost possible. The relatively high price of electricity in the area, due to its presently high costs of generation, has somewhat restricted its fullest utilization on the farmo Abundance of supplies together with lower prices would be accompanied by much greater consumption and lower unit costs as has been the universal pattern in the United States. Special power uses, such as for heating, for crop drying, for irriga- tion and drainage undoubtedly have been inhibited by supply and price limitations. For example, it is recognized that much land otherwise suitable for agriculture necessitates drainage during certain periods of the year. Electric pump systems are therefore likely to be em- ployed in greater number with the passage of years. Sprinkler irriga- tion likewise is believed to be an important and imminent development due to the fact, that, in the area under consideration, soil moisture is quite low in the early portions of the growing seasono Its use might also enable soil temperatures to be somewhat higher due to the solar radiation-absorbing effect of moist soil surface as contrasted with those which are dry. Although some crop drying has been attempted on a small scale, there is reason to believe that lower power prices and a more adequate supply would be a factor of encouragement for this practice. Examples can be multiplied as to the beneficial effects re- sulting if electric power supplies were more abundant and of a lower price structure. A-12 PORTL.AND. CREGON NOR T H PAC I Fie CON S U L TAN IS .. .. .. .. .. • • • .. • .. .. - - - - - With population increases taking place and certain to con- tinue, the place of agricultural production in the Kenai Peninsula- Anchorage-Hatanuska Valley area is an important one to meet local civ- ilian and military needs for food supplies. It will result in a broadening base for an expanding agriculture with consequent increas- ing demands for goods and services which could be met locally thus creating an upward spiral in the overall economyo G. FOREST Contrasted with southeastern Alaska, the potential volume of commercially important timber is much smaller o However, the forest resource can become more economically more important than it is today. The greatest potential for forest resource utilization probably lies in the stands in the Knik Arm-Hatanuska-Susitna area, which contains important volumes of birch, spruce and some hardwood species. Although much attention has been given to the utilization of the birch for furniture and peeler stock, no harvesting has yet taken place. The possibilities of large-scale logging operations in conjunction with a pulp mill for the production of specialized bleached birch and other hardwood pulp species for consumption by West Coast pulp and paper plants is under investigation at this time.. This would also make feasible the selection of high-grade birch logs for export to the furniture and plywood industries of the States. The establish- ment of such a forest products industry would create new payrolls in the area, would stimulate wood-lot operations by farmers and could result in an increased acreage of cleared land at low cost for new farm operations. Power requirements would be substantial for even a mininnlm sized pulp planto H. MINERALS The dearth of reliable information on the mineral resources of the area and the heretofore restricted interest by mining opera- tors to the precious metals does not allow for a realistic appraisal of economic development potentials in this field of activity outside of two or possibly three major items o The chromi tes of the Kenai Peninsula area are now being mined on a "high-grade" baEJis for government stockpile purposes. However, the overall resource is substantial enough to warrant con- sideration for local processing into materials having a higher value per pound or ton than available in the crude ore o Thus, there is a distinct possibility that, in the near future, a beneficiating plant will be required in the general vicinity of the deposits. Power re- quirements for such a plant would be quite large 0 There is also the possibility of establishment of a ferroalloy electric furnace plant in the Kachemak Bay area o The processing of chromi te ores into A-13 PORTLANO • OREGON N a RT H P At I F IC CON S U l TA NT S ANCHORAGE. ALASKA - .. ... .. ... • .. .. • .. ... ... -- - - ... - - ferroalloy material can be effectively accomplished in the same type of electric furnace as required for the production of calcium carbide, the material used for the manufacture of acetylene gas. This possi- bility warrants considerable attention. A combination ferrochrome- calcium carbide i'urnace plant would have the important advantage of permitting intermittent operations for the production of either mater- ial, depending upon seasonal ore supply conditions or market fluctua- tions. Furthermore, it might provide a market for other local raw materials of the Kachemak Bay area such as limestone and coal, and possibly for waste wood from sawmill operations o The feasibility of such an operation will require substantial investigations of raw materials suitability, adaptability of processes, plant logistics and other relevant factors of establishment. Such investigations are now being prosecutedo Power requirements would be substantial, ranging between ,,000 to 7,,00 kilowatts for a minL~ sized operationo The large coal resources of the area --as in the Homer, Beluga and .Hatanuska valley areas --may also warrant considerable attention in the future. The possibilities of processing these coals for the production of high BTU, low volatile, carbon material as fuel for local utilization as well as for export cannot be disregarded o Considerable investigation will be required of processing techniques, markets for products and byproducts as well as of overall costs • During the past two years, there has been tremendous explor- atory and land-leasing activity on the part of major oil companies. These have carried out extensive programs of geophysical work, par- ticularly starting with 19", and have undertaken major programs of drilling to ve~J great depthso Within the area under consideration, this activity has centered along the west coast of Kenai Peninsula on pook Inlet and in the lower reaches of the Matanuska valley. Ex- penditures in the millions have been reported. In the event commer- cial oil fields are proven, the possible effect on the economy of the entire area would be substantial. Although it is much too early to prognosticate with any degree of certainty. The discovery and produc- tion of commercial petroleum would undoubtedly necessitate the estab- lishment of refinery facilities in the general vicinity of the fields. Power requirements for such industrial plant operations are very large. APPENDIX D. TOPOGRAPHIC FEATURES II) TOPOGRAPHY Cooper Lake is located at 1670 -h,' West longitude and 60 0 -23' North latitude on the Kenai Peninsula of Alaska, Third JUdicial District. Its distance from Anchorage is " air-miles and 102 miles by highway, and is ,2 miles by highway from Seward • The western part of Kenai Peninsula bordering Cook Inlet is A-lh PORTL.ANC • OREGON NOR T H P A ( I F I ( ( 0 N S U L TAN T S ANCHORAGE. AL.ASKA - - • .. .. • • • .. .. • • .. .. -.. .. - - a low alluvial plain extero.ding from the water to the Kenai Hountains and averaging 30 miles in widtho The Kenai Mountains cover the east- ern and southern part of the Peninsula from Turnagain Arm to Katchemak Bay. The Cooper Lake Project is located in the geographic center of the Anchorage-Kenai Peninsula area served by the individual REA Cooperatives, affiliated as the Central Alaska Power Association for the purpose of providing integrated generation and transmission facil- ities .. J. TRANSMISSION NETWORK Transmission facilities center in the area of Cooper Landing to serve: Moose Pass, Lawing and Seward to the East and South; Kenai, Kasilof, Ninilchik, Homer and Seldovia to the West and South; and con- nect northward to the Turnagain Arm and Anchorage areas. The mountain- ous area adjacent to Cooper Lake provides sites for a number of hydro- electric plants as well as the potential hydroelectric sites at Skilak Lake, Tustumena Lake, Bradley Lake and projects on streams in the southwestern area • The C09per Lak~ Project will serve as the initial project for a network of hydroelectric power transmission serving the entire area, thus establishing the basic unit of an integrated system. The potential power in Kenai Peninsula will be ample to provide all the needs of the area and furnish needed generation capacity to the Anchorage-Matanuska area e A-15 PORTL ... ND • OREGON H 0 R T H P A ( I F I ( (0 N S U l TAN T S ANCHOR"'G£. AI. ... SK ... - I ... • • • • • • • • • - - - - - - CLDT.ATOLOGY AND HYDROLOGY PORTLAND, OREGON NO RT H PAC I F IC (0 N S U l TA N T S ANCHORAGE, ALASKA - • ,. • • • • • • • .. - - .. .. - - CONTENTS Climatology and Hydrology I. 'Climatolo gy II. A. B • Co D. Eo F. General - - - - - - - - - - Climate Controls - Precipitation ----- - Snowfall - - - - - - - - -• Temperatures -- Evaporation - - - Hldrology A. Stream-Flow Characteristics B~ Spillway Design Flood - L General --- ------ ---~ 2 .. Snow-Melt Flood -- ---- -- 3. Rain-on-Snow Flood -- 4. Spillway Design St9rm ------ 5. Losses -------- 6. Unit Hydrograph - -------- 7. Spillway Design Flood Hydrograph C. Water Yield - ----... ---- L. Run-Of.f ---------- 2. Adj acent Are as -- - - 30 Storage Required --- D .. Spillway ------- L General ------ 2. Spilhvay Site ------ ---- 30 Spillway Operation ---- 4" Spillway for Full Development -- 5. Downstream Channel ------ - Eo Freeboard --------- F. .Sedimentation ----- - ------ G. Ice Conditions ------- - -- H. Downstream E.f.fect of the Pr.oject 1. Area At.fected - - ------- - 2. Stream Flows ---- I. Power Plant Tailwater - --- - --- - - --------- ---- --------- - ----- --- ------ --- - - -- - - - - - - ?ORTI.. .. NO • OREGON NOR T H PAC I Fie CO H S U l TAN T S ANCHOR .. GE. AI.. .. SK .. E-1 E-1 E-1 E-2 E-3 E-3 E-4 E-5 E-5 E-5 E-6 E-6 E-7 E-7 E-7 E-7 E-7 E-8 E-9 E-9 E-9 E-9 E-lO E-ll E-11 E-ll E-12 E-12 E-13 E-13 E-14 E-15 - _I" .. .. • • • • .. • • - - - - - - - I. CLDL4.TOLOGY A. GENERAL The climate of the Cooper Lake region may be classified as humid sub-arctic •. ,.Temperature, precipitation and other climatic ele- ments are transitional between the wet, mild coastal regions border- ing the Gulf of Alaska and the cold, d~J interior north of the Alaska Range. Because of the considerable range in elevation of the basin tributary to Cooper Lake, 1168 feet at the lake surface to 5270 feet at the top of Cooper Mountain, there are marked variations of climate within the basin in spite of its small size. The extensive conifer- ous forests with heavy underbrush, characteristic of the lower ele- vations, have a taiga-type climate. With increasing elevation the climate becomes progressively more severe, and much of the higher portion of the basin has a tundra-type climate, with lower vegetation forms such as bushes, mosses and lichens. Small northward sloping areas on the highest peaks have quasi-permanent snowfields, indicat- ing that a polar-type climate may be approached. B. CLIMATE CONTROLS Principal climatic controls are the topography, the prox- imity to the Pacific Ocean and the Gulf of Alaska, and the general atmosph~ric circulation over the area. The Aleutian Low, a semi- permanent low-pressure trough which persists over the general North Pacific Ocean region, is the most significant atmospheric circulation feature affecting the area. It tends to follow the annual march of the solar altitude, weakening and'moving northward into Bering Sea in the summer and strengthening and moving southward into the Gulf of Alaska in the winter. The general storminess of the region is due to cyclonic storms associated with the Aleutian Low and the tendency for successive storms to cross the area in series in a generally west-to- east direction. Normally, these storms follow a path somewhat to the south of the Kenai Peninsula, but occasionally the storms move directly over the peninsula or to the north into central Alaska. Al- though the Kenai Peninsula is subject to frequent fall and winter cyclonic storms, thunderstorms are rare, and tornadoes and hurricanes are unknown. C. PRECIPITATION On the basis of very limited data, the normal annual pre- cipitation of the basin tributary to Cooper Lake outlet is estL~ated to be of the order of 50 inches. In view of the pronounced varia- tions in precipitation with elevation, basin orientation, and other topographic factors, precipitation data obtained at points outside the basin cannot be applied to the basin without adjustment. It is E-l PO~T"'AND , OREGON N 0 RT H PAC J F IC CON 5 U L TA N T S ANCHORAGE. A ... ASKA - - • • • • • • • • • - - - - ,. - - considered that neither the relatively long record for Seward nor the shorter record for the geographically closer station at Cooper Land- ing are representative of the amounts of precipitation which fallon Cooper Lake Basino The estimate of 50 inches normal annual precipi- tation is based on a number of factors including run-off data and loss estimates, vegetal cover j air flow patterns, and precipitation data adjusted for areal transpositiono During storm conditions the wind is usually from the south or southeast, so that considerable orographic lifting occurs on the coastal side of the Kenai Mountains. For this reason, precipitation is probably not as heavy over the Cooper Lake basin as over the Resurrection River Basin just across the divide to the southo An effort was made to develop a precipitation record for Cooper Lake basin by correlation of the rainfall records at Kenai, Naptowne (Sterling)~ Moose Pass, Seward and Cooper Landingo These records were spotty and no pattern could be established even though the run-off record of Cooper Lake gave a key to conditions. Although precipitation depths and intensities normally cannot be transposed without adjustment, the seasonal distribution of precipitation as determined from the records of stations in the general area is believed to be similar to that of Cooper Lake Basin. April through July is normally the period of least precipitation~ and September and October the months of greatest precipitation. Frequently, over half the annual precipitation occurs in the 4-month period, September through December. Much of this late summer and early winter precipitation is directly associated with renewed activity of the Aleutian Low, with south or southeast winds import- ing moisture~laden air from the Gulf of Alaska. The yea.~to-year variation of annual precipitation is moderate except for a year of heavy run-off at 5 to 10 year intervals. This is a matter of considerable importance in evaluating the hydro- power potential of the basin and indicates the necessity for large storage to insure firm powero Since long-term records are required to determine annual variability, the data for Anchorage, Matanuska, and Talkeetna, in addition to those for Seward, were analyzed even though the first three stations are some distance from Cooper Lake. The study indicated that departures of more than 20 percent from the annual mean are common and departures in excess of 40 percent from the mean may occur. Annual precipitation at Seward and Cooper Land- ing, for the period of record, is shown on Plate Do SNOWFALL A SUbstantial portion of the winter precipitation on Cooper Lake Basin falls in the form of snow, much of which is retained in natural storage in that form until the following summer. The per- E-2 PORTLANO • OREGON N 0 RT H PAC IF ICC 0 N S U LT ANT S ANCHORAGE. ALASKA - • • • • • • • • • - - - - - - centage of the total precipitation which falls as snow increases with basin elevation, but no data are available from which to de- termine such percentages. It would appear reasonable, however, that over three-fourths of the precipitation above elevation 2,500, which comprises nearly half the basin, falls as snow. About ten percent of the basin lies above elevation 3,800, and it is est~~ated that only a very minor portion of the precipitation on that upper area falls as raL~o E. TEHPERATURE No temperature data are available for the Cooper Lake Basin, but estimates may be made on the basis of short records for Cooper Landing, Moose Pass and Naptowne, and the longer record for Seward. It appears that winter temperatures at or near the elevation of Cooper Lake are, on the average, somewhat comparable to those of North Dakota in that normal minima of -200 F 0 and extreme minima of -55 0 F. may be expected. Considering all the stations in the Kenai Peninsula -Cook Inlet area, minimum temperatures of record are gen- erally between -300 F. and -500 F. Extremely cold periods are gen- erally caused by a high pressure area stagnating over central Alaska and expanding to dominate the circulation over Kenai Peninsula. December, January and Febru~~ are the favored months for extreme cold spells, which are usually of 3 to 10 days duration over Kenai Peninsula and contiguous areas. During the summer season, the comparison with North Dakota does not apply. Summer temperatures, both normals and extremes, are considerably lower in the Cooper Lake area than in North Dakota or any other agricultural area of the continental United States. From a study of all available temperature records, the probable temperature averages were developed for Cooper Lake by using the Cooper Landing temperatures and applying an adiabatic lapse ratio of 3 degrees per 1,000 feet of elevation. This data is shown on Plate No. ItE-l". F. EVAPORATION Estimates of evaporation and transpiration losses from the Cooper Lake Basin are necessarily very preliminary, since no evapo- ration data for the area are available. Most of the annual total occurs during the summer months when the temperatures are the highesto The evaporation facvor is relatively unimportant since it is already deducted from the run-off as measured by the stream gaging station near the lake outlet. A dam to pool elevation 1,192 would increase the lake area by about 400 acres. In general the reservoir w~uld be E-3 Pom ... NO. OREGON NO RT H PAC I fie CON S U L TA N T S ANCHOft ... GE, AL ... SK ... - -.. .. • • • • .. .. • - - - - - - - at the lower levels during the spring and early summer months. If the ultL~te pool level is Elev. 1,200 the increase in area over the original lake area will be 600 acres with an average throughout the year of 300 acres. Assuming an evaporation of 24" to 30 1t per ann~~ from the water surface, the increased loss over normal from the reservoir due to evaporation would be about 1 cubic foot per second. This loss is allowed for in the flow available for power. II. HYDROLOGY A. STREAM-FLmv CHARACTERISTICS The stream-flow regimen of Cooper Creek differs consider- ably from the annual precipitation pattern in that the peak run-off normally occurs in June or July, at which time the precipitation is usually low. The summer freshet is produced largely by snow-melt run-off and is therefore characterized by a slow, gradual rise and recession, often extending over a period of several weeks. Minimum flows usually occur in the late winter or spring season, before the advent of the summer heating necessary to melt the snow. During the water years 1950-55, average annual run-off from the 31.17 square-mile area tributary to the gaging station near the Cooper Lake outlet was 89 second feet, or 39 inches over the basin. Minimum average annual discharge was 60.5 second feet in 1952, and the maximum average annual discharge was 151 second feet in 1953. The lowest mean monthly discharge, 9.1 second feet, occurred in March 1950, and the highest mean monthly discharge, 408 second feet occurred in June, 1953. The maximum peak' and maximum daily mean discharges, 695 and 689 second feet, respectively, occurred on June 29, 1953. Plates Nos. II and III illustrate the normal seasonal stream flow regimen of Cooper Lake outlet by graphically showing minimum average and the maximum mean monthly discharges and the hydro graph for the period of record. As shown, the June-July snow- melt maximum ~s very pronounced, accounting for over 40 percent of the annual total on the average. This may be compared with only about 3 percent of the annual total in the two months of lowest run- off, March and April. This seasonal run-off distribution is char- acteristic of most of the streams of the general region. Also shown on Plate No. II is an annual run-off summary for Cooper Lake outlet. It may be seen that the 1953 water year run-off was much higher than that for the other five years, a re- lationship whicfi'was the case also at a number of other Kenai E-4 PORTLAND. OREGON N 0 RT H P At I F I ( (0 N S U l TA N TS ANCHORAGE. ALASKA - .' .. • • • • • • • • • - • - - Peninsula streams. On the basis of all available stream flow and precipitation data, it is estimated that the 1953 run-off volume was about 70 percent greater than a long-term nOrmal. An average recurrence interval for that unusually great water run-off might be roughly 10 to 15 years. On the other hand, the run-off during the other five years, appears to be considerably below a long term normal. Even L~cluding water-year 1953, it appears that the period of record for the Cooper Creek gaging station may be about 10 per- cent below a long term normal. A mass hydro graph of run-off for the basin is shown on Plate No. II. B. SPTI.LWAY DESIGN FLOOD 1. General. In the development of a synthetic flood for spillway design purposes, three basically different types of floods were considered, as follows: (a) A pure snow-melt flood with relatively low peak and high volume. This type flood would occur in June or July, when the lake level would probably be low at the start of the flood. (b) A rain-on-snow flood, with both rainfall and snow- melt contributing to the flood. This type flood would be most likely during the period March-May, when most or all of the basin would have a snow cover, and a potential exists for moderate rain. (c) A rain flood with little or no snow melt. This type flood would occur during September -November, when meteorological conditions are most favorable for maximum precipitation intensities. Detailed studies and comparisons of each of the three types of floods led to the conclusion that an intense rain flood with no snow melt would provide the most severe conditions for spill- way design purposes. 2. Snow-Melt Flood. Preliminary snow-melt design floods were derived by two independent approaches; a frequency analysis of the short streamflow record, and snow-melt computations utilizing a degree-day factor. The frequency method was eliminated because of the unsatisfactorily short period of record and the generally recognized deficiencies of the method when a frequency curve is extrapolated far beyond the period of record. Use of records from other stations to extend the record by the station-year method is not considered proper because E-5 PQRTLANIl • OREOON N 0 IT H P A ( I F JC (0 N S U L TA N T S ANCHORAGE. ALASKA - -, - .. .. .. .. .. .. .. - - - - - - - several streams may react concurrently to the same causes; that is, the records do not reflect independent events. The method of theo- retically~elting the snow pack by applying an assumed heat supply (air temperature) yielded a reasonable and satisfactory hydro graph , but the peak discharge was appreciably lower than those derived from rainstorms o Although most annual high water events in this area are caused by snow melt, the peaks are limited by physical limitations on snow melt rates unless an extremely great heat supply is assumed, a condition considered unrealistic • 3. Rain-on-Snow Flood. A rain-on-snow flood would have a higher peak and lesser volume than a pure snow melt flood. Preliminary results indicated that the basin average snow melt would not be sufficient to compen- sate for the decreased rainfall potential later in the winter season when an extensive snow cover would be present. One factor which would tend to limit basin average snow melt lies in the fact that different elevation bands in the basin would make their maximum melt contribution at different times during the course of the storm; on the lowest portions of the basin, rain might be falling on snow free ground; on slightly higher slopes, rain might be falling on a thin rapidly melting snow cover; at higher elevations, the rain might be largely or entirely absorbed in a thick snow cover, and at the high- est elevations, snow might be falling. Perhaps the most important consideration is that the maximum rainfall potential is lower in winter and early spring than in early fall. 4. Spillway Design Storm • The adopted spillway design flood was based on the storm of September 9-11, 1917. This storm was the greatest of record at Seward and was reported by the Il/eather Bureau to have "culminated in a disastrous flood that, at Seward and along the line of the Government Railroad, caused a loss estimated at $100,000". Recorded maximum one, two and three-day precipitation at Seward was 7.2, 11.6 and 13.3 inches respectively. A depth duration curve for those data, constructed on the assumption that they represent maximum 24, 48 and 72 hour intensities, is shown on Plate No. III. Also sh~wn on Plate No. III is the depth duration curve for the same storm transposed to the Cooper Creek Basin. The trans- position factor applied was the square root of the ratios of normal annual precipitation, approximately So inches for Cooper Creek Basin and 70 inches for Seward o An adjustment factor of 0.855, derived in this manner, was applied to the Seward curve for all durations. The estimated 72-hour precipitation on Cooper Creek Basin amo~~ts to 11.37 inches. E-6 PORTLAND. ORI.QON NOR T H PAC I FIe CON S U L TA N T S ANCHORAGE. ALASKA - • • • .. .. • • • • .. - - - • - - Losses. The transposed September 1917 storm was rearranged into a storm pattern as shown in Spillway Design Storm, Plate No. III. Three hour increments were used because of the small size of the basin. Losses, consisting of infiltration, surface detention, evaporation and transportat.ion were estimated as shown in the table. It was considered that the losses would decrease from 0.15 inch per 3 hours at the start of the storm to 0.07 inch per 3 hours at the end of the storm. Total 72 hour losses amount to 2.57 inches, leav- ing 8.80 inches of water excess available for run-off. 6. Unit Hydrographo Although floods resulting from intense rainstorms would be of potentially greater magnitude than snow melt floods, the com- bination of meteorological events necessary to produce such a rain flood would occur only very infrequently. No rain flood has occurred in the short period that the Cooper Creek gaging station has been in operation, necessitating that the unit hydro graph be developed from the basin characteristics. A modification of Snyder's synthetic method was utilized in the derivation of the uni~ hydro graph for the 31.17 square miles tributary to the gaging station. Peak discharge of the 3-hour unit hydrograph, shown on Plate No. III, is 2230 second- feet, or 71 second-feet per square mile. Ordinates of the unit hydro graph, in l.5-hour increments, are tabulated on the hydro graph. 7. Spillway Design Flood Hydrograph. The table on Plate No. III shows the computations which combine the water excesses and the unit hydro graph into a spillway design flood hydrograph. The resulting flood hydro graph , with slight graphical smoothing, is shown on the Plate. The peak discharge is 5,350 second-feet, or 172 second-feet per square mile, and the 5-day volume, including base flow, is 17,100 acre-feet. The flood volume, exclusive of the assumed base flow of 200 second-feet, amounts to 15,100 acre-feet • The final spillway design flood shown is not the maximum possible flood which would result if all meteorological and hydro- logical conditions were extrapolated to the physical upper limits. It does, however, represent a flood which would be of veri rare occur- rence. Because of the physical approach utilized in the derivation, there is no sound method of assigning an average recurrence interval to the flood. Subjectively, however, an assumed average recurrence interval of the order of 50 to 200 years does not appear unreasonable. C. WATER YIELD 1. Run-Off. E-7 PORTLAND. OREGON N 0 RT H P A ( I f JC ( 0 N S U L TA N T S ANCHORAGE. ALASKA - .. .. • • • • • .. - - - - - - - Run-off records are available for Cooper Lake outlet for the past 6 years and the average yield is 88.7 o.f.s. This 6 year period includes the 70% above average year of 1952-53 and a down- ward adjustment is indicated. On the other hand the long term pre- cipitation record at Seward (33 years) indicates that the 6 year period under investigation is l2~% below the 33 year average. The net adjustment for these variations results in an estimated average run-off from Cooper Lake of 93 c.f.s. A deduction of 2% for in- accuracy in measurements leaves the net run-off for power from Cooper Lake at 91 c.f.s. On the 31.17 square mile drainage area (19,950 acres) this is equal to 40 inches in depth per annum. 2. Adjacent Areas. There are two small streams that may be diverted into Cooper Lake or its pipe line system which can be utilized to augment the prime power available at the powerhouse. Ptarmigan Creek drains 1.91 square miles (6.1% of Cooper Lake drainage area) and can be readily diverted into the power conduit. Stetson Creek, which lies to the west, drains 9.31 square miles (30% as large as Cooper Lake drainage area) and can be diverted into Cooper Lake through a short canal. The run-off characteristics of these small streams is assumed to be similar to the measured discharge from Cooper Lake, and the inclusion of both would increase the total prime power from the Project by 30%. A deduction is made for no flow from Stetson Creek during the three coldest months of the year. The estimated net flows available is as follows: Cooper Lake alone • • .. .. • • • • • • • • • • • • •• 91 c. f. s. Cooper Lake plus Ptarmigan Creek • • • • .. • •• 96 c.f.s. Cooper Lake plus Ptarmigan Creek plus Stetson Creek. 123.75 c.f.s. An allowance of 5075 c.f.s. is deducted from the Stetson Creek total because of estimated losses due to waste through spill dur- ing peak floods, due to frozen canal in winter and some seepage at dams, leaving a maximum net for power purposes of 118 c.f .s. As the discharge of these streams varies greatly from a minimum of 10% of their mean during winter freeze-up to a maximum of 700% or more during peak floods, it is obvious that, to obtain the relatively uniform draft required for prime power, SUbstantial storage is required. This Project is fortunate in having Cooper Lake available as practically a ready made storage reservoir covering 10% of the drainage area. The required storage may be secured from this 2,150 acre lake either by drawdown of the lake itself, or by raising the lake by the construction of a small dam at the outlet where econom- ical damsites are available, or by a combination of these two methods. These alternatives' will be discussed under Project Lay- outs. E-8 PORTLAND. OREGON NOR T H P At I FIe CON S U l TA N T S ANCHORAGE. ALASKA - .. .. .. .. .. .. ill .. .. .. .. - • - - 3. ,Storage Reauired. On power streams it is desirable to develop a maximum of storage consistent with economy. Without storage, the low flow from Cooper Lake would be the present measured winter discharges -viz: 10 to 12 c.f.s. for months at a tL~e, and the Project would not warrant development as the cost of the outlet tunnel alone would exceed the power values available in the winter months --the season of highest demand • By means of the Mass Hydrograph, shown on Plate No. II, the storage required for various rates of yield is readily determined, and is shown on the Storage-Yield Curve, Plate No. E-2. It is found that a dependable, continuous discharge of 62 c.f.s. may be obtained from Cooper Lake with a storage of about 16,000 acre-feet or less than 8 feet drawdown on the Lake; 25,000 acre-feet would provide 75 c.f.s. continuous, and 58,000 acre-feet would be required to regulate Cooper Lake to its average of 91 c.f.so over the 6 years of record. If Ptarmigan Creek were added to the system a storage of 6),000 acre-feet would yield 96 c.f.s., and if Stetson Creek were added, a storage of 73,000 acre-feet would yield 118 c.f.s. (after deducting assumed losses). D. SPILLWAY 1. General. Cooper Lake reservoir surface area at elevation 1192 will be 2600 acres or 13.00% of the total drainage area and will therefore have a marked retarding effect in smoothing out the discharge from the reservoir. The maximum daily discharge of record including the 70% above normal year of 1953 was 695 c.f. s. Such an inflow into the reservoir would raise the pool level only t foot per day even if there were no spill or power draft whatever. From the detailed study of reservoir fluctuation throughout the years shown on Plate "E-3" it may be noted that because storage capacity is sufficient for complete control of the inflow, there should NEVER be any spillover the dam. To insure this condition (no spill) the power draft through the tunnel can be increased in the year of maximum run-off as the reservoir nears top elevation, thereby holding the~ool level down. 2. Spillway Site. Absolute safety of the dam, however, dictates an adequate spillway, and such a one is provided around the left abutment. Sound rock is found at an elevation suitable for the spillway lo- cation and as most of the excavation for the spillway, including E-9 PORTLAND, OREGON N 0 RT H P A c/ F It CON S U L TA N T S ANCHORAGE, ALASKA - • • • • • • • •• • .. .. .. • - - the rock, will be used in the dam itself, the added cost of provid- ing the spillway will be very low. The approach channel will be depressed slightly to facilitate outflow, then there will be a 20 ft. wide level sill of solid rock for control of spill at elevation 1,192c Downstream from the sill there will be a solid rock channel on a slope for easy get-away back to the original river channel. Referring to the Hydrograph on Plate III it is noted that, the months of maximum run-off are June and July and during those months, the reservoir is being refilled from the heavy power draft of the preceding winter and spring during which time the power draft greatly exceeds the inflow to the reservoir. As the reservoir nears the refill stage in the months of August and September, the daily inflow has reached nominal proportions again and heavy spill should not occuro The addition of Stetson Creek to Cooper Lake will not materially affect the spill conditions because the capacity of the Stetson Creek diversion canal will be less than 100 c.f.s. 30 Spillway Operation. The design flood (see Par. II-B of this Appendix) of 17,100 acre-feet volume in 5 days with a peak discharge of 5,350 c.f.s. has been routed through the reservoir assuming the reservoir full at beginning of the flood and the powerhouse shut-down. Plate VIII shows a graphic representation of the course of events, hour by hour. The width of the spillway is 40 feet with the sill at Elevation 1,192 and the crest of the dam at Elevation 1,202. The reference plate shows the Spillway Rating Curve, Sur- charge Storage, InflOl-r and Spillage Curves and the Reservoir Level as they are interrelated during the assumed period of the UDesign Stormu • As the run-off reaches the reservoir, spill starts and the reservoir begins r~s~ng. Each increases until at about 60 hours, the storm has reached its peak and rapidly declines. The reservoir level peaks at 88 hours ~ (depending upon its discharge capacity) and declines gradually due to the surcharge storage on the reservoir (13,500 acre-feet of the 17,100 acre-feet of volume in the flood). Depth over the spillway will be 5.2 ft. at peak discharge and gradually decline as the surcharge storage is carried off. The peak flood discharge was estimated at 5,350 c.f.s • and the resulting peak discharge over the spillway was found to be only 1,300 c.f.s. Even this is nearly twice the peak flood of record. In this historical case the lake was assumed II full'! at the start of the storm. In the future, the "fullll reservoir condition is very remote. In reservoir and spilh-ray studies it is used as the most critical condition possible. There seems little danger of spillover the spillway -especially after a year or two of plant operation. E-IO PORTLANO • OREGON N 0 RT H P A CI F I ( ( 0 N S U LT ANT S ANCHORAG£, ALASKA - -( . .. .. • .. .. .. • • .. • - - - - - - In case of damage to the spillway during overflow, there should soon be ample time for repair if need be, as the reservoir would be down several feet immediately after flood season • 4. Spillway for Full Develonment. The spillway sill would be raised to elevation 1,200 and the dam to 1,210 if Stetson Creek flow is to be diverted to Cooper Lake for the full development~ This will increase the power stor- age in the lake to 80,000 acre-feet, and the regulated yield to 115 Cof ~ s. 56 Downstream Channel. The downstream channel of Cooper Creek is confined in a narrow gorge except for the last one-half mile before emptying into Kenai River • The gorge section of the river will carry all possible flows without causing any damage to natural resources and there are no man-made improvements.. The lower one-half mile is more open with flatter gradient and lower banks which could result in some flooding. This area has a small camp site developed by the Forest Service and a highway bridge over the mouth of the creek. Damage to the highway and the bridge is not anticipated and damage to the camp site would be negligible. The effect of the project would be to reduce the flow of Cooper Creek and with the diversion of Stetson Creek under the full development the peak flows would be further reduced. Flows which would result from a storm of the magniturle used for the spillway design flood would no doubt do considerable damage to highway, bridge, and camp site. The effect of the project on this peak flood would be to reduce the peak flow to approximately 50%. E. FREEBOARD The freeboard on the dam for the spillway at elevation 1,192 or 1,200, discussed above, will be 10 feet above the maximum storage elevation and spillway sill, and 5 feet above maximum water surface elevation. Since the planning of the reservoir contemplates no spillage over the spillway, the freeboard will be 10 feet plus, except in those rare instances when there is an exceptionally wet year and low power consumption, and then only if the inflow to Cooper Lake were exceptionally rapid and not anticipated. In the proper operation of the project and its integration into the overall power system of the area, steam and/or diesel power should be shut down to the extent, the Cooper Lake project operating at peak output would be capable of carrying, thus depleting the reservoir sufficient to accommodate any forecasted large ir£low. E-ll PORTL.ANO , OREGON N 0 RT H P A ( IF I ( (0 N S U l TAN T S ANCHORAGE, ALASKA - - - • • • • • • • • - - - - - - - The locatic'n of the reservoir is such that it is sheltered from strong w.L~ds illld also the necking of the lake at a point l~ miles from the dam will dampen • ..rave action materially. Maximum height of waves at the dam should not exceed 5 feet in any case. The upstream face of the dam will be riprapped with rock obtained from the spillway excavation to amply protect it against all conditions of high water and w'ave action. F. SEDIMENTATION The inflow into the lake consists principally of drainage from the steep mountain slopes adjacent to the lake. There are no glaciers feeding directly into the lake but in several locations it is possible to have snow and ice slides which could bring in con- siderable amounts of rock and dirt. There are two or three streams flowing into the southerly end of the lake and two approximately miles from the dam which do carry considerable amounts of silt which will be deposited in the reservoir. The sedimentation in the lake is mainly composed of rock particles rather than silts and clays since the lake water remains clear at the outlet even during the periods of maximum flow. The volume of the lake below elevation 1,150 is not known, however, the depth of the lake varies up to a maximum of approxi- mately 300 feet which I·muld indicate a volume in excess of 300,000 acre feet. Assuming an average turbidity of 300 ppm, the volume of silt which could be deposited in the lake would be in the neighbor- hood of 20 to 30 acre-feet per year. Considering this amount of silt deposit as compared to the total silt volume, it would indicate that there is sufficient capacityto contain all deposited silt for a period of 10,000 years. Hence, the sedimentation in the reservoir will offer no problem in the operation of the project. G. ICE CONDITION Cooper Lake is subject to freezing from December through May and will be frozen over approximately four months each year as an average condition. During this time, the inflow is reduced to a matter of 10 or 15 second-feet while the power demand will exceed 100 second feet. This condition will require the upstream face of the dam to be riprapped with sufficiently large stone to prevent damage from the movement of the ice by reason of the drawdown as well as the effect of winds pressing the ice against its surface. Since the trend during the ice period will be the lowering of the lake surface, sheets of ice will be left lying on the upstream slope of the dam. This will not disturb the riprap and will, in effect, provide additional pro- tection against ice pressures. The fact that the lake will be frozen E-12 F'ORTLANO • OREGON N 0 RT H P A CJ F I ( ( 0 N S U l TA NT S ANCHORAGE. ALASKA - • • • • • • • • - - - -- - - over entirely most of th~s period -there being' only a brief period at the begirJl1:ing of the cold lie ather and at the time of break-up, that free ice will be floating on the lake -further reduces the exposure of the dam and other structures in the lake to ice damage. The power intake structure will be located so that ample depth below the frozen surface will be available to draw out the requirement for power without necessity of breaking the intake free. The intake will be planned with a curtain wall at the entrance to the conduit extending below the lowest level of water intake and the chamber behind the curtain wall Inll be provided with heat to prevent freezing in this space in which the intake gate will be locatedo This type of intake, it is believed will be completely free from icing difficultieso The trash rack located outboard from the curtain wall vdll be confined between the concrete abutments of the intake which will protect it from severe ice loadingo There will be ample depth from minimum ice elevation to the bottom of the intake st~~cture to assure ample area for the passage of the power flows 0 H. roWNSTREAH EFFECTS OF THE PROJECT 1. Area Affected. The natural outfall from Cooper Lake flows into Cooper Creek at a point approximately h~ miles from Kenai River. Approxi- mately 60% of the water flowing from Cooper Creek flows from Cooper Lake. Of the remaining hO%, approximately half is the flow from Stetson Creek. No beneficial use being made of the flow in Cooper Creek. However, there have been some hydraulic mining operations along Stet- son Creek. A major operation above Cooper Creek just downstream from Stetson Creek utilized water from two streams flowing from the hill- side to the west of Cooper Creek and north and west of Stetson Creek. This operation was dormant at the time inspection was made o The use of all water flowing from Cooper Lake and Stetson Creek for power pur- poses would not seriously interfere with these operations if they were revi vede Hydraulic m~~g operations on Stetson Creek above the pro- posed point of diversion could be permitted without seriously affecting the use of the water diverted for power, provided the operation was at least 500 feet upstream from the point of diversiono Operations in the section of Stetson Creek below the point of diversion, approx- imately 0.6 mile from its mouth, would have difficulty in obtaining sufficient water during the latt,er part of the summer unless the oper- ation were to channel water from other streams north and west of Stetson Creek or divert the amount required from the diversion dam .. This situation is quite improbable since the Stetson Creek Canyon E-13 PORTLANO , OREGON NOR T H P A ( J F I ( (0 N S U LT ANT S ANCHORAGE, ALASKA - - • • • • • • • • • - - - .. - - from Cooper Creek, to a point well above the proposed diversion dam site, is in a rock-lined canyon with little or no glacial outwash material in which hydraulic mining operations would be feasible. 20 Stream Flows. The natural flow of Cooper Creek at the highway bridge (adjacent to Kenai River) has been developed from the known records at the gaging station on Cooper Creek near the outlet of the lake. The resulting q.ata is plotted on Plate No. "E-411. This plate shows the average monthly flmvs over a five-year period together with the maxL~um monthly and the minimum monthly average for each month ex- cept for the months of January, February, March, April and Hay, during which time frozen conditions, air temperatures and the avail- able record from the gage at Cooper Lake make it difficult to pre- dict the probable maximum and minimum average monthly flows with any dqgree of accuracy. Plate No. liE-51! shows the monthly averages for the average month, maximum month and minim~~ month over the five-year period for the flows at the highway bridge, after Cooper Lake fl01" is diverted and after Cooper Lake and Stetson Creek flows are diverted. This same information is plotted in a continuous hydrograph on Plate II. These values are plotted for a point 0.7 of a mile above the mouth of Cooper Creek, which is the section of the river accessible to the anadromous fish which spawn in its waters. Curve "An shows the flows after diverting all flow from Cooper Lake.. Curve liB!! shows flows after diverting all flow from Cooper Lake and up to 70 c.f.s o from Stetson Creek .. From a study of the data referred to above, it is clearly evident that the flow diversions of both Cooper Lake and Stetson Creek would eliminate to a large extent the severe flood conditions on Cooper Creek during June, July, August, September and October and would still maintain an average £low varying £rom approximately 2$ second feet to 65 second feet. This flow would maintain a reasonable amount of water in Cooper Creek for both sports fishing and fish spawning purposes. No definite information was obtainable as to the actual flows during the w~ter months at the mouth of Cooper Creek. Some people interviewed indicated that there was a small flow in the creek and others said that at times they were sure that the stream was completely frozen and no free water flowing. To clarify this situ- ation, negotiations are under way to obtain records through this winter, January to April, 1956, with the purpose of obtaining data on the winter flows for the benefit of both the Fish and Wildlife Service and the Central Alaska Power Association. Fish life in Cooper Creek should not be materially affected adversely by the diversion of all flow from Cooper Lake nor from the E-14 PORT~ANC , OREGON N 0 RT H PAC I Flee 0 N S U l TA N TS ANCHORAGE, A~A$KA - ~' • • • .. .. .. .. • .. .. - - - - • • - possible future diversion of flow from Stetson Creek. There is en- closed as Exhibit "E-6 11 , a Preliminary Memorandum Report by the Fish and Wildlife Service on the Cooper Creek basin which indicates that in their opinion a very limited detrimental effect could be antici- pated from the accomplishment of this project as planned or for the ultimate project as proposedo I. POi1ER PLANT TAJL1.r1ATER The discharge from the turbines goes directly into Kenai Lake. The added flow into the large body of water has no effect on lake level. The fluctuations in the level of Kenai Lake are the result of the run-off of the entire drainage basin and the discharge characteristics of Kenai River. Kenai Lake varies from a normal minimum elevation of 433 in the late winter to normal maximum ele- vation of 438 in August with a probable maximum of 4420 E-15 PORTLAND, OREGON NOR T H PAC I Fie CON S U l TA N T S ANCHORAGE, ALASKA - ,. ,. ,. • ,. II ,. ,. .. .. .. .. • .. - COOPER LAKE PROJECT MONTHLY AVERAGE TEMPERATURE SUMMARY Ac(jusled values ror Cooper Lake For 5 wafer years -Ocl: 1949 fo Sept /954 ltJ ~ 30 K -q: C\: ~ 20 ~ ~ f-.... 10 -/O~~·--~~~~--~~~--~~~--o N D J F M A M J J. A S MONTH Norlh Pacific Consul18nfs PlafeNo.c.1 .. .. .. • • .. • • - - - .. - - COOPER LAKE PROJECT STORAGE -YIELD CURVE 5 Year Record-Gcl: /949--Sepf 1954 130 Limil 90 V) ~80 U ~ 70 '" ~GO I.tJ ~ 50 k5 .,,/ '/i I cr V / t~ / f'~ I ~ I vY v " 0° I :\ 9 I r(\1 I ~ ~ ./Liml/ ~~ I , ~L' 'I \L' J .... d,~rrr;! Iml i 'v'C / ~ ke a~e e,~~ ~ De( ",0' .... Cl e :;-,,",0 () ~~ ~- I i I I ) (( 120 110 100 AO I I 20 V 10 o 10 '20 30 040 50 rc,o 70 80 STORAGE IN /000 A eRE FE £. T Norfh Pacilic Consulfc;nl.s Plafe No. E-2 l I 1200 /192 1190 ~ ~ "'\ //80 ~ ~ "-I 4J 1170 1166 //60 • I I l • .. • .. • I • a a I 1,49 1950 1951 1952 1953 /954 1955 OND JFMAMJJASONOJFMAMJJASONO JFMAMJJA$ONOJFMAMJJASOND JFMAMJJASONO J~::~J~~ Cl ~dc ~ r-.. '-t\. I-~ '-I--I-- ~-~ v ~ I--~ 1--KI -it l-I-- 1--I--I--it I--l- -~-I-- I---I--1-- I = I--~ -~~~ ~-'-~~ ~ I cD/··~ r-[) • r/l,J-vl9l\1 ,/1# 'I I-t(~, "'"" = ':0 tE -00 If I.--' k v"-6' [) 'r-ir t:5lclc D V' f-"k.: I' PI 1/ " .... f-I--V V-I""- t---too-V I r'\ V II ~p r-D.tJ I(~ lJ. r li" '( t? ~,fJ I ~ I j II--K lr~) v. ~. ~ ~ls' IJ 1'\ lJl I 1--1--I-!-1---1--f-I-f\ II r.... I-' ~ f\ 1/ ...... ~ i\. I--I-~ r---1---~ 1---~I-\ 1I ~ II~ R I-~-~ ~ f-I---'" I-- 1\ " ~ H l\ V ttf} ~ t--l-I---I--~-I, ill l\ V I'i J I\. I 111 f1. rO) I? fl 11' t( lIltr ..., ~r) I-c ;., ~Is-vr I_V Ii 171"'-r'tJ , , , I I I FiRST STEP -COOPER LAKE ALONE FLUCTUA TIONS OF RESERVOIR F ~-I~ 1\ 1-- r\ I--r-...U I I Q=90CFS Prime Power = 91=90 x 734;: 1/ ~ I il nl I I I Avera.qe Head= 7.34;:1 14 f/ Ins/al7 12.,OOOf(.W= 40%PlanfFacfor: 4750KWcon,nuous. • () o o -0 rT1 ]J r ):> A rn u Xl o L rn () -I - - .. - - - - - COOPER LAKE PR OJECT MONTHLY FLOW OF COOPER CREE.l< AT HIGHWAY BRIDGE-NATURAL CONDITION (Average;?maxirnurn and min/um J/8/ues Tor fhe 5 year period Ocl 1949 fa Sepf 1954) o N D J F M A M J J A S MONTHS Norfh Pacific Consulfanfs Plafe No. £-4 - • • • • •• • • - - - - - - COOPER LAKE PROJECT MONTHLY FLOW OF COOPER CREEK AT HI6HWAY BRIDt3E-AFTER COOPER LAKE IS DIVERTED (Avea:Je.! maximum and minImum values Tor fhe 5 year period Oel 1949 fo Sept /954) 280 240 200 IGO 120 I, ~ ~Ma )(. m( 'Dnf)) ~ " " "" A vt: . m( ~nf} ."-"-"-"-Mir. . m(~nff. ~ ~ ~ ~ ~ v///, ~! ~ W f77~ ~/h ~ V/// 'l/~ ~ ~"'~ ~ " " ~"'''0 I o N D J r M A M J J A S MONTHS MONTHLY FLOW OF COOPER CREEK AT HIGHWAY BRIDGE --AFTER COOPER LI<. & STETSON eK. ABOVE EI. 1200 ARE DIVERTED. ! I I '20 J---.,.----;---+--+---+---+--+----+-----F;~~---+----I ~~ I o N 0 J F M A M J MONTHS Norfh Pacific Consul/anls Plale No. £-5 - - • • • .. .. • .. • • .. • - - Extracts From: f1emorandum dated April 18, 1955. From: The Director (U.S. Fish and Wild Life Service) Subject: Application by the Chugach Electric Association, Incorpor- ated, of Anchorage, Alaska, for Preliminar,r Permit for water Power Project, FPC Noo 2170. Dolly Varden and rainbow trout, the principal species in Cooper 1qke, are utilized to a limited extent because of the relative inaccessibility of the lake. Cooper Creek at the present time con- stitutes a relatively unimportant salmon spawning area; however, a sport fisher,r of moderate importance is located in the lower mile of the creek. Rainbow and Dolly Varden trout as well as a few king salmon are the principal species ~taken by anglers. The outflow of Cooper Lake would be diverted through a pipe line to a power house with a de-watering effect on the upper third of the stream and reduced flows through the lower two-thirds as a result of such diversion • Moose, mountain goat, Dall sheep, and black bear are the big game species in the drainage, while fur animals include mink, beaver, lynx and wolverine. ~unor destruction to the habitat of moose, beaver, lynx and wolverine would result through inundation and stream de-watering; however, such effects would be insignificant. The Department of the Interior is charged with the manage- ment of the salmon and sport fisher,r'resources of Alaska and there~ fore cannot agree unconditionally to any reduction of such habitat. On the other hand, ~~e Departw~nt cannot oppose this permit in view of the project's limited issues. Therefore, we request that any permit for this project be conditioned by the requirement of maximum cooperation from the Permittee in searching for project operational standards least harmful to fish and wildlife resources and for sup- plementary mitigation measures. Under these circumstances it is requested that any prelim- inary permit isSued for this project include the following stipulation~ The Permittee shall, during the period of the per- mit, cooperate with the Fish and Wildlife Service and the Territorial Agencies concerned with the management of fish and wildlife resources with the specific intent of developing a plan least harmful to these resources, giving primar,r consideration to the maintenance of ade- quate flows in Cooper Creek to preserve its salmon~pro ducing capacity and sport fishing potential and such mitigation measures as may appear desirable and reason- able. Plate E-6 PORTLAND, OREGON NOR T H P A ( J F ICC 0 N S U l TAN T S ANCHORAGE. ALASK .... - • .. • • • .. .. .. - - - - - - - APPENDIX "Fit GEOLOGY AND FOUNDATION EXPLORATION by Fred O. Jones Geologist SEISMIC SURVEY by Gahagan Construction Corp. Geophysical Survey Division Donald E. Reed -Seismologist Included as Section VI F'OFlTL. ... NC • OFlEOON NO RT H PA ( I F I ( (0 N S U L TA N T S ANCHOFl ... OE. AL. ... SK ... -- - • • • .. • .. .. .. .. • • • - • - - CONTENTS Geology and Foundation Exploration I. Introduction II. A. B. Regianal Setting - Scope of Investigations Summary and Conclusions A. B. C. D. E • F. G .. Project in General - Damsite - - - - Reservoir Basin Tunnels Conduit --.-- Penstock - - - Power Plant -- III. Geology and Exploration of Project Features IV. A. B. C. D. E. F. G. Damsite - - - - - - - - - - - - - - - - - - - - 1. Bedrock Formations - - - - - - - - - - - - - - - 2. Distribution and Attitude of Slate-Graywacke Series - - - - - - - - - - - - - - - - - - - 3. Permeability and Stability - - - - - - - - - (a) Surficial Deposits of Compacted Glacial Outwash and Till - - - - - - - - - - - - - (b) Surficial Deposits Consisting of Loose, Pervious Glacial Outwash, Sand and Gravels- 4~ Geologic Reconnaissance for Construction Mater- ials - - - - - - - - - - - - - - - - - - - (a) Impervious Borrow Materials (b) Pervious Borrow Materials ( c) Riprap - - - - - - - (d) Concrete Aggregate 5.. Slides - - - - - - - Reservoir Site - - Tunnels - - - - - - - - - 1. Exploration 2. Intake Area - - - - 30 Rock Conditions - - - - - - - - 4. Comparison of Cooper Lake with Other Tunnels Conduit - - - -- - - - - - - - Penstock - -- - - - - - - - Power Plant - - - - - - - - Earthquakes - - - - - - - - - Regional Geology F-1 F-1 F-2 F-2 F-3 F-3 F-3 F-3 F-3 F-4 F-4 F-5 F-5 F-6 F-6 F-6 F-7 F-8 F-8 F-8 F-9 F-9 F-10 F-ll F-12 F-12 F-13 F-14 F-14 F-14 F-16 A. General Geology - - - - - - - - - - - - - - - - - -F-17 PORTI.. ... ND • OREGON NO RT H P A ( I Fie ( 0 N S U l TAN T S ANCHOR ... GE. AI.. ... SK ... - .,/ Page B. Stratigraphy ------- --------F-18 • l. Slate and Graywacke ---- ------ - F-18 2" Unconsolidated Deposits - - -----F-19 Co Structures --------- ------F-21 • l. Cleavage ---- -- - ------F-21 2" Joints --- -- - -------F-21 3. Faults ------- - --F-22 D. Geologic History ----- --F-22 • 1. Pre-Tertiary --F-22 2" Tertiary ----- ---F-23 3. Quaternary ---- ----F-23 • E. Bibliography ---- - ------F-24 V" Photographs • Plate F-l -Photo No. 63 -Quarry near mouth of Cooper Creek Plate F-2 -Photo No. 42 -Cooper Lake and reservoir basin .. Plate F-3 -Photo No. 7 -Ridge between Cooper Lake and Kenai Lake, showing tunnel line Plate F-4 -Photo No. 31 -Ridge between Cooper Lake and Russian River drainage • Plate F-5 -Photo No. 49 -Thin-bedded blue black slate Plate F-6 -Photo No. 48 -Interbedded slate and graywacke Plate F-7 -Photo No. 54 -Interbedded slate and graywacke • Plate F-8 -Photo No. 52 -Joints and faults in graywacke formation Plate F-9 -Photo No. 57 -steep, anticlinal fold in interbedded slate and graywacke Plate F-lO-Photo No. 51 -Graywacke at Blast Hole No. 6 Plate F-ll-Photo No. 11 -Aerial oblique of powerhouse, pen- stock and surge tank area • VL Seismic Survey .. Gahagan Construction Corp., Geophysical Survey Division - - - - -FORT~ANC • OREGON N 0 RT H PAC I Fie CON S U tT ANT S ANCHORAGE. ALASKA - .., • • • • • • • • • -.. - -.. - - Ie INTRODCCTION A. REG IONAL SETTING The Cooper Lake Project is in the Kenai Mountains of the Kenai Peninsula of Alaska o The peninsula is divided into two dis- tinct physiographic provinces ~ the Kenai Mountains and the Kenai Lowland. The mountain province makes up approxiJnately two~thirds of the area j extending along the east side of the peninsula from Turnagain Arm and Prince HilHam Sound to Port Chatham and the Chugach Islands. It is bounded on the east by numerous bays and inlets of the Gulf of Alaska and on the west by the lowlands. The mountains have summit elevations up to 6,000 feet with as much as 5~000 feet of local relief. They are extremely rugged and have a complex drainage pattern which reflects a complex geologic structure modified by ice and water erosion. Glaciers once filled most of the valleys to an elevation of 4~000 feet leaving only the higher ridges and peaks protruding above them. The southern and eastern parts of the mountains are now occupied by glaCiers having ice fields from which many large valley tongues radiate. Near the ice fields lie many small separate glaciers. The Kenai Lowland province makes up approximately one-third of the peninsula. It is bounded on the east by the mountains and on the west by Cook Inlet. The lowland is a product of repeated episodes of glacial erosion and deposition within a bedrock trough, with subsequent modification by wind, stream, tidal and frost processes. The topography exhibits a wide range of glacial and associated glaciofluvial forms such as moraines~ outwash aprons and plains, kames~ and eskers. Most of the lowland lies within 400 feet of sea level, surfaces are flat to undulating, and local relief varies from a few feet to more than 200 feet. B. SCOPE OF INVESTIGATIONS The geological investigations and foundation explorations summarized in this report have been directed toward establishing the geological feasibility of the proposed Cooper Lake Hydroelectric De- velopment. Two earlier preliminary reports were availableg 10 Geological Investigations of Proposed Sites at Cooper, Grant, Ptarmigan, and Crescent Lakes, Alaska. George Plafker -open file report by U. S. Geological Survey 0 2. Geologic Report on Cooper Lake Project. \'lilliam Ro Judd -U. S. Bureau of Reclamationo In addition to these two project reports, several publica- tions of the Geological Survey describe related geological features of the area. These data provided an invaluable basis upon which to formulate the program just completed. F-l PORTI.AND • OREGON NOR T H PAC I Fie ( 0 N S U LT ANT S ANCHORAGE. AI.ASKA - ~I • .. • • .. • • • .. - - - - - - This program of investigations consisted of detailed geo- logic field studies correlated w~th the subsurface explorations. Field examinations were begun on July 10, 1955 and continued through October 1, 1955. Subsurface explorations consisted of programs of drilling, test pitting, trenching, and seismic work. All features of the project were investigated including damsites, reservoir basin, tunnel, conduit line, surge tank, penstock, powerhouse, and con- struction material sources. II. SUMHARY AND CONCLUSIONS A. PROJECT IN GENERAL From the geologic investigations just completed and sum- marized in this report, it is concluded that the Cooper Lake Project is completely feasible and very favorable for construction. B. DAMSITE 1. Because of the high stability and low permeability of the foundation members, the damsite investigated at the outlet of Cooper Lake is suitable for a dam of the height proposed or one even higher. 2. Investigations indicate that adequate quantities of materials are available in the immediate area of the damsite for con- struction purposes. Surface exposures and diamond drill holes #4 and #5 indi- cate that the interbedded slate and graywacke in the left abutment at the damsite is of suitable quality for rock fill or riprap. Ex- cellent quali~ of graywacke outcrops 1600 £eet downstream and ex- tends down Cooper Creek for one-half a mile. Tests of the slate bedrock forming the left abutment show the rock is of excellent quality and completely adequate from a standpoint of stability and impermeability. The bedrock in this area occurs at a favorable elevation for a spillway location. Subsurface exploration in the damsite area reveals that bedrock is mantled with a stratum of very compacted glacial outwash and till. Permeability tests in six drill holes show that loss of water by percolation through it will be negligible. 3. From superficial examination, the lower damsite appears to be as favorable as the one explored. Should additional project studies indicate that it might be more advantageous to construct, it should be explored by the combination of' methods used at the upper site. F-2 PORTLANO • OREGON N 0 RT H P A CI f I ( ( 0 N S U L TAN T S ANCHORAGE, ALASKA -r III, • • • .. .. • • • III - - • - - C. RESERVOIR BASIN The Cooper Lake Basin is geologically favorable for reser- voir storage. The relatively impermeable rock formations along prac- tically all of the proposed reservoir shore line and the presence of high level surface and ground water conditions over broad areas of the divides separating the Cooper Lake Basin from other basins pre- clude any significant loss of water by seepage. D. TUNNEL The tunnel will penetrate a series of steeply dipping slate and graywacke rocks at a direction nearly normal to the formation strike. Abundant geologic data relating to this stratigraphic section indicate that tunneling conditions will be good to excellent. It is expected that less than 20 per cent of the upper tunnel will have to be lined for support, that ground water volumes will be minor, and that bverbreak can be held to less than 5 per cent. Rock conditions in the lower tunnel ridge are not so well known as in the upper tunnel ridge, but there is no reason to expect that conditions differ greatly. The nearness to the surface and higher water pressures will require this tunnel section to be lined. E. CONDUIT On the selected route only a few hundred feet of pipe con- duit will be required in the crossing of Ptarmigan Creek, from the main tunnel to the short second tunnel under the surge tank. This section of pipe will be adequately buried, anchored and covered as conditions dictate. F. PENSTOCK The short penstock down the steep hill will be buried and anchored to rock at all grade changes. Suitable foundations for pipe anchors can be found almost any place along the line. Investigations indicate that the depth to bedrock between rock exposures will probably average between 5 and 10 feet. G. pmVER PLANT A power plant location has been selected on the shore of Kenai Lake where bedrock formations outcrop. The rocks are graywacke interbedded with minor amounts of slate and will provide an excellent foundation for the installation. There is no evidence, in the field, of snowslide activity in the vicinity of the powerhouse. F-3 PORT~ANO • OREGON NOR T H P A ( IF I ( ( 0 N S U l TA N T S ANCHORAGE. A~A5KA -f - - II • .. .. • - - - - - III. GEOLOGY AND EXPLORATION OF PROJECT FEATURES A. OOrSITE The Cooper Lake Damsite area at the outlet of the lake is at a point in the valley where there are relatively high ledges of bedrock and where materials of glacial origin choke the floor of the valley. The geologic formations in the site area may be divided into three groups -1. The bedrock of slate and graywacke, 2. Surficial deposits of ice-compacted till and glacial outwash, which are rela- tively impermeable, and 3. Surficial deposits consisting of a mix- ture of loose pervious glaCial outwash, sand, gravel, and talus • Exploration of the site was begun in 1954 by the U. S. Bureau of Reclamation. In that investigation one drill hole was put down near the center of the river channel and two test pits were dug, one in each abutment area. The exploration just completed has been a continuation of that work, and new holes and test pits were num- bered in the series already begun. The earlier logs and test pits are included on the enclosed maps and cross sections, and logs have been reproduced to accompany the logs of new drill holes and pits. Exploration of the damsite consisted of detailed field studies, a seismic program, the putting down of six additional diamond drill holes, two new test pits, the deepening of one of the earlier test pits, and the excavation of one hand trench and one bulldozer trench. Two rock outcrops were blasted for samples and visual ob- servation, one in the graywacke formation and one in the slate for- mation. In the seismic program 40 spreads were shot for a total of 9,380 linear feet and 50 shot points; 3 spreads were shot in areas of possible borrow materials for a distance of 660 linear feet and 5 shot points • The location of the damsite axis selected for investigation and the positions of the various exploration features are shown on Plate V, IlCooper Creek Dam Geology". Logs of the test pits, diamond drill holes, and trenches are shown on Plate VI. A report on the seismic investigation, which was unusually successful in differentiating the formations in the area, is attached as Section VI of this Appendixo 10 Bedrock Formations. Bedrock formations in the da~site area consist of slate and graywacke. The slate is thin-bedded, blue-black in color, and is interbedded with occasional thin beds or lenses of fine-grained graywacke. Drill holes Nos. 4 and 5 on the left abutment penetrated the slate, and in both holes it was found to be of excellent quali~ F-4 PomANC • OREGON N 0 RT H P At I F I ( ( 0 N S U l TAN T S ANCHORACE. AL.ASKA • ". • • • • • • • • • .. .. - .. .. - - with scarcely any weathered zone beneath the contact of surficial materials with the bedrock. Surface outcrops show weathering vary- ing from a fevl inches to three or four feet in depth.. The gray- wacke is thick-bedded or massive in formation, fine to medium grained and extremely hard. 20 Distribution and Attitude of Slate-Graywacke Series. Exposed and thinly covered (15 feet or less) slate bedrock makes up the left abutment of the damsite, Plate V. Depth to bed- rock across the rest of the site from Station 6+00 to Station 14-1-00 varies from 40 feet to over 100 feet. The depths determined by seismic methods along the site and in the area just upstream and downstream are plotted on the geologic map and are also to be found in the seia~ic report. All of the bedrock in the right abutment area and downstream to the slate-graywacke contact is believed to be slate and generally similar to that making up the left abutment. Its strike varies but in general is N.10 to 20 degrees E. Dips vary from 60 to 70 degrees E. Photo No. 63, Plate "F-l", shows an outcrop near the mouth of Cooper Creek where similar rocks have been quarried for riprap. Near the slate-graywacke contact at the lo"\ver damsite location, the dip of the rock is more variable. Due to this variability, one of the earlier interpretations was that these rocks represented a slump block. More detailed studies of the structure show that these rocks are not a slump block but simply show a variation in the bedding near the contact. This same variation in the thinly bedded slate has been found at numerous other locations in the area and is not unique. Changes in dip are the result of more intense folding and faulting in the contact zone. 30 Permeability and Stability. The slate bedrock forming the left abutment of the damsite was tested in both diamond drill holes Nos. 4 and 5. The tests showed no loss of water whatsoever at 50 psi •. Details of the core drilling are shown on the logso The rock is all of excellent quality and is completely adequate from a standpoint of stability and permeability • The bedrock in this area occurs at a favorable elevation for a spill- way location, and it is entirely feasible from a geologic viewpoint to divert the river during construction by a tunnel through the abutment rock. The slate which would make up a part of the right abu~~ent at a lower damsi te has not been explored by drilling and testing. Field examinations, however, indicate that it is of good quality and relatively impermeable below the zone of surface weathering. The graywacke formations along which most of a lower damsite might be built are excellent foundation members. They are not present at the site which has been explored so no test to confirm judgment has been made, but it is believed that they are relatively L~ermeable. There F-5 PORTI-AND • OREGON N 0 RT H PAC IF ICC 0 N S U l TA NT S ANCHORAGE. AI-ASKA -r .. .. .. .. • .. .. ,. - • - - is no question regarding their stability, and they could support a dam many times the height of the one being considered for construction • (a) Surficial Deposits of Comnacted Glacial Outwash . and TilL Subsurface exploration revealed that bedrock in the damsite area is mantled with a stratum of very compacted glacial outwash and till. This member is a part of the moraine formed 'When the Cooper Lake Basin was being gouged out by a glacier. The rela- tively impermeable materials of which it is composed are boulders, cobbles, gravel, sand, and glacial flour of silt and clay sizes. The material mixture changes rapidly from place to place and depth to depth, which is characteristic of deposits formed at the terminus of a huge glacier. Its extreme compactness indicates that a great thickness of ice must have a'c one time overridden it and compressed it into its present state. In every place where it has been opened for visual inspection, it is so hard that it is difficult to stick a pick into it. Permeability tests in six drill holes show that it is almost water tight and that loss of water by percolation through it will be negligible. Test data are shown on logs of drill holes, Plate VI • The stratum of ice-compacted glacial outwash and till will form the foundation member for the dam from approximately Section 5+50 to the right abutment. Depths of 2 to 20 feet to this member along the damsi te axis and in the damsi te area in general are shown on Plate V. Along the axis of the damsite, the thickness of the ice compacted member varies from 0 feet to over 100 feet. This foundation member is entirely adequate from a stability standpoint to support the dam proposed or one much higher should engineering studies indi- cate that a higher dam is desirable • (b) Surficial .Deposits Consisting of a M:Lxture of Loose, Pervious Glacial Outwash, Talus, Sand and Gravel. Mantling most of the damsite area is a layer of loose surficial material, Plate V. It is made up of several types 'Which cannot be accurately separated by field studies, and their separation was not of sufficient importance to conduct detailed subsurface ex- plorations to do so. The mantle consists of talus along the valley side, fingering into terrace sand and gravels on the benches and both of these merging imperceptibly into alluvial and wind blown deposits. These loose materials would need to be excavated along a cut-off trench at the base of the dam, but throughout the rest of the founda- tion area they constitute no stability problem and may be incorporated into the structure of an earth fill dam. 4. Geological Reconnaissance for Construction Haterials • F-6 PORTL.ANO • OREGON NOR T H P A ( I Fie CON S U l TAN T S ANCHORAGE. AL.ASKA - • .. .. .. .. .. .. .. .. .. .. .. .. - - The following is a description of the geologic reconnais- sance for construction materials. (a) Impervious Borrow Materials • Possible sources of impervious borrow material were studied in the outwash till complex of the damsite area and in a terminal moraine on the left side of Cooper Lake l~ miles upstream from the damsite4 Reconnaissance investigations were also made of lake beds near the confluence of Cooper Creek with Kenai River and at selected locations a-~and Cooper Landingo Damsite Area Exploration in the damsite area revealed that sec- tions of the compacted till-glacial outwash complex contain an abundance of glacial rock flour of silt and clay sizes o The bull- dozer trench on the left abutment and the drill hole setup at diamond drill hole No o 6 exposed the material well, and a sample was taken from the trench for testing. It is believed that a sufficient quantity of this material can be found in the damsi te area for construction of the impervious section of an earth fill dam4 West Moraine Area A tributary valley enters the Cooper Creek Valley l~ miles upstream from the damsite area on the left. The valley has been heavily glaciated and aerial studies indicate that the center of the terminal moraine could be accurately located. This center zone of the terminal moraine should logically contain the maximum amount of fine material ground up by the glaciero The area was investigated by a seismic line and a hand trench. The log of the trench may be found on Plate VI. The investigation revealed that beneath a mantle of approximately 15 feet of loose rocks and soil, there is a 25 foot zone of glacial till of sand, gravels, and boulders containing a considerable amount of rock flour of silt sizeso There are large quantities of this material available. Mouth of Cooper Creek Area Geologic studies indicate that two terraces near the mouth of Cooper Creek may be favorable locations for impervious borrow material. These terraces lie between elevations 700 feet and Boo feet and between elevations 900 feet and 1000 feet on the right side of the valleY4 The access trail to the damsite crossed both terraces. Approximately 25 auger holes 1.rere attempted in an effort to prospect the area. Augering was not successful because of the stony character of the deposit. The greatest depth penetrated by F-7 PORTt. ... NO • OREGON N 0 RT H PAC I F I ( (0 N S U l TA N T S ANCHOR ... GE, At. ... SK ... - • • • • .. • • • .. .. .. • - - any auger hole was 14 inc.hes o • If suitable deposits in sufficient quan- tity are not found clo;ser to the damsite in preconstruction investi- gations, it is recommended that this area be prospected in detail. Cooner Landing-Sterling Highway Location Reconnaissance in the Cooper Landing area revealed extensive deposits of silty, clayey till along the Sterling Highway four miles east of the Kenai River bridge. This till area extends along the highway for 17 miles. It is relatively impermeable mater- ial and is found in tremendous quantities. In view of the fact that it is considered likely that all necessary impervious material can be developed at the damsite by detailed investigations, no exploration or testing of the deposit was conductedo (b) Pervious Borrow Materialso Pervious borrow materials may be obtained from the surface stratum of loose sand, gravel, and boulders in the damsite area or from colluvial deposits along the left side of the damsite area. In both places the materials are suitable and abundant. Fur- ther exploration in the construction stage of the project will be required to outline the most favorable borrow areas. (c) Riprap. The interbedded slate and graywacke which forms the left abutment of the damsite is the closest source of riprap. Sur- face exposures and cores of diamond drill holes No. 4 and 5 indicate that it is of suitable quality. It is very hard, and the nearly ver- tical attitude of the beds favors quarrying operations. Photo 63, Plate ItF-l" shows a quarry near the mouth of Cooper Greek in similar rock formations. It is believed that the left abutment rock mass will q'uarry equally well. Outcrops of excellent quality graywacke begin 1,600 feet downstream from the damsite investigated and extend along Cooper Creek for over half a mile. If the rock at the left abutment is not found to be suitableI' qua.r.:y sj.tes should be explored in this section of graywacke. Should a lower damsite be investigated, it· will be principally in this graywacke formation, and an abundant quantity of riprap would be readily available at the site. Cd) Concrete Aggregate -Damsite Area. Concrete aggregate materials are not readily available in the damsite area. Two possible sources, however, are considered favorable from a geologic point of view. They are the coarser phases of the glaCial outwash in the left abutment area of the damsite and the formations of massive graywacke downstream from the site. F-8 PORT~ANO • OREGON N 0 RT H PAC I Fie CON S U L TA N T S ANCHORAGE. A~ASKA - .. • • • • • • • .. - - -.. - - Test pits Nos. 1 and 4 penetrated glacial outwash mixed with only minor amounts of till. A large percentage of the rock material is graywacke, and only small amounts of the deposit are made up of platey slates. It is believed that by washing and crushing selected portions of these deposits, a suitable aggregate can be produced at the damsite. A 300 pound sample was taken from test pit No. 4 for inspection purposes and testing. Present plans do not contemplate the use of concrete at the dam, hence aggregates were not made" The graywacke bedrock formations in the downstream area are of suitable quality for crushing and processing into con- crete aggregate. 5. Slides. In the damsite area, there is no recognizable ,evidence of the common type of snow slide which cuts out a strip of vegetation and leaves a mass of debris near the toe of the slope. There is evidence, however, of one or more snow slides of the jump type. This type occurs where a long, steep, snow-covered slope has a slight rise near its base. The rise hurtles the fast moving snow out and farther down the slope like a skier making a long distance jump. A clearing, just downstream from the damsite axis on the left side of Cooper Creek, is evidently the result of a jump snow slide from the right side of the valley. It contains a mass of twisted, broken and crisscrossed trees. Future slides of this type may be expected from the high mountain slope. No evidence of rock slides exists in the damsite axis area, but just up the valley on the right bank a small knoll sits out a short distance from the bottom of a steep gully. This is thought to be the result of an ancient rock slide or a combination rock and snow slide of the jump type. The damsite axis has been selected to avoid the area which has been affected at least once and possibly more than once by snow slides. ','Because of the intervening terrain between the toe of the steep mountain slope and the damsite location, there is no danger of snow slides from the left side of the valley. All installations at the damsite, however, should be protected from snow slides from the right side of the valler_ B. RESERVOIR SITE The reservoir basin is a broad U-shaped valley -Photo 42, Plate "F-2". Its shape up to an elevation of approximately 4,000 feet reflects intense glaciation. Glacial scour deepened the original Cooper CreeR Valley forming a basin-like depression in the bedrocks of gra~~acke and slate. The bottom of the glaciated lake basin is F-9 PORTL.ANO , OREGON N 0 RT H PAC I Fie CON S U l TA N T S ANCHORAGE, AL.ASKA - .. .. • • • • • • • ---.. .. - - known to be over 400 feet below the present level of Cooper Lake. Subsurface investigations in the area show that only the upper 60 to 100 feet of Cooper Lake may be accounted for by the presence of glacial deposits choking the outlet of the lake. The Cooper Lake Basin is separated from the Kenai Lake Basin by a broad bedrock ridge through which the power tunnel of the project will pass - Photo 7, Plate IfF-3". The rocks are relatively impermeable and sup- port high ground water throughout the area. The basin is likewise separated from the Russian River drainage by a broad divide of bed- rock formations -Photo 31 j Plate "F-4n. t1any small high level lakes dot the surface of this area indicating ground water and surface water much higher than the proposed Cooper Lake Reservoir. The same combination of high surface and ground water conditions exists in the area of low terrain just west of the damsite area. The presence of these high level surface and ground water conditions over broad areas of the divides separating the Cooper Lake Basin . from other basins precludes any significant loss of water by seepage. The tunnels for diverting water from the Cooper Lake Basin to a power plant on the shore of Kenai Lake will penetrate bedrock ridges of slate and graywacke formations of Mesozoic Age. The ap- proximate alignment of the tunnels, a geologic cross section, and other features of the geology are shown on Plates VII and IX. Photo No.7, Plate "F-3", shows an aerial oblique view of the ridge between the two lakes and the approximate position of the upper tunnel line over the ridge. Cooper Lake is in the left foreground, Kenai Lake in the background. The slate and graywacke rock formations are hard, consoli- dated beds of mud and sand. Due to severe folding and faulting, the bedding now stands at steep angles, and in many places it is nearly vertical. The strike of the formation is unusually uniform for such a highly folded area. It varies from N. 10 degrees to 15 degrees E. The high angle dips alternate from east to west, reflecting the in- tense folding of the strata. Some of the beds may even be overturned. Very little can be told about the character and quality of the rocks from the surface along the tunnel because of the heavy vegetation cover. Very little could be learned by drilling because of the extremely lim- ited thickness of strata which a drill 'hole would penetrate. For- tunately, the regional geologic structure is such that many of the beds which the tunnel will penetrate are exposed along the shore of Kenai Lake. Furthermore, the structure of the entire mountain pro- vince of the Kenai Peninsula is such that the same series of slate and graY"'.vacke beds is repeated time and time again. Miles of rock cuts along the highway and railroad system and eight tunnels of the Alaska Railroad have been driven through similar or identical rock formations • F-lO PORTLAND. OREGON N 0 RT H PAC I F I ( ( 0 N S U l TA N T S ANCHORAGE, ALASKA -f _r • • • • • • • • • • • -.. .. • - - 1. Exploration. The tunnel formations were investigated by field examina- tions in the tunnel area, along the shore line of Kenai Lake, and throughout the Kenai Peninsula where similar formations have been handled in engineering works. Eight locations were blasted along the shore of Kenai Lake in order to make visual examinations of rep- resentative parts of the stratigraphic section and to secure sampleso The locations of the blast holes and the position of all rock samples taken in the investigation are shown on Plate Vllo The rock samples are available for inspection in the office of the Central Alaska Power Association in Anchorage. Between the tunnel inlet at Cooper Lake and approximately Station 11+40, the tunnel will penetrate thin-bedded blue black slate. The slate is interbedded with occasional thin beds or lenses of gray- wacke, Plate IX. Photo No. 49, Plate !IF-51! shows rocks exposed along the shore of Kenai Lake which are typical of the formation to be encountered in this section of the tunnel. Between Stations (approximately) 11+40 and 25+50 and 31+50 and 44+co, the tunnel will penetrate interbedded slate and graywacke. The slate is blue-black in color and beds range from one-eighth inches to four inches in thicknesse Much of it has a slatey cleavage para- llel to the bedding planes. The graywacke is light gray in color and occurs in beds or lenses. The relative amounts of the two rock types and their quality may be seen on the following photographs: Photo 48, Plate tlF-6 11 ; Photo 54, Plate IlF-7"; Photo 52, Plate "F-8"; and Photo No. 57, Plate "F-9 11 • Between Stations (approximatelY) 25+50 and 31+50 and 44+CO and 55+50, the tunnel will penetrate graywacke with minor amounts of interbedded slate. The graywacke is of excellent quality, thick-bedded to massive. Photo No. 51, Plate "F-10" shows the character of this rock at blast hole No.6. This is believed to be representative of the rock the tunnel will penetrate throughout the two sections' out- lined above. Between Station 55+50 and 57+00, the tunnel will penetrate slate which is finely fissile or very thin-beddedo Rock conditions and types are not so well known in the lower tunnel ridge as in the upper tunnel ridge, but there is no reason to expect physical characteristics greatly different from those in the upper tunnel. The nearness to the surface of most of this short tun- nel and relatively high hydraulic pressures will require a reinforced concrete conduit • F-ll PORT~"'NO • ORIGON NOR T H P A ( I f I ( (D N S U l TAN T S ANCHOR ... GE. A~"'SK'" - .., ,/ • • • • • • • • -- -- • - - 2. Intake Area. Details of the geology of the upper tunnel intake area are shown on Plate IX. The area was investigated with one seismic line and one test pit. Bedrock of thin-bedded blue-black slate lies at a shallow depth (6 to 10 feet) between the lake shore and Station 3+50~ The material overlying bedrock consists of one to two feet of organic material and then sand, gravel and broken rock. Numerous outcrops of the bedrock near the shore line show that it is of good qualityo All of the beds have steep dips with re- versals of dip not uncommon. The general strike of the formation is N. 10 degrees to 15 degrees E. Studies indicate no unusual diffi- culties in the construction of the intake o The bedrock is suffici- ently competent to stand on 1/4 to 1 or vertical slopes. Some air slacking may occur, but it should be so minor as not to be detrimental to the construction. The geology of the outlet area, originally selected, was carefully investigated and visual inspection of the recommended outlet area indicates similar geological formation. One test pit was put down at elevation 1,160 feet on the original site and is shown on Plate VII. The exact position of bedrock at the relocated portal is not known, but general geologic relationships indicate that it will not be deep. 3. Rock Conditions. Tunneling conditions through all of the rock strata will be good to excellent. The first 200 feet to 400 feet at the portal ends will be somewhat broken and soaked with ground watero These sections will probably need to be supported. Between these end sections, nearly all of the tunnel should stand unsupported, and only minor amounts of ground water are likely to be encountered. Short sections where the rocks are sheared or faulted and where the joint system in the massive graywacke produces blocks may need to be supportedo The traces of several possible faults are shown on the geologic map. Actually, these are only lineations which are prominent on the aerial photographs of the area. They may represent faults, they may represent major joints, or some other geologic feature. Even though they are faults, it is not expected that they will present any special problem in tunneling. Hundreds of faults were crossed in the three miles of tunnels along the Whittier Branch of the Alaska Railroad, and many can be observed in highway cuts between Cooper Landing and Seward. These faults vary in width from a quarter of an inch to 12 or 14 inches, some carrying small amounts of ground water. The fault zone is ground, mashed, and deformed, but the rock immediately adjacent is scarcely affected by the faulting. It may be expected that many faults will be encountered along the tunnel with no serious consequences. Should support be re- quired in any of the sheared or faulted zones along the tunnel lL~e, it probably will not extend for more than 100 to 200 feet. It is not expected that more than a total of 1,000 feet of the entire upper tunnel will need support. F-12 PORTL.ANO • OREGON NOR T H PAC I FIe ( 0 N S U l TAN T S ANCHORAGE. AL.AS1<A - _/ I - .. III iI • • • • • • .. .. -- • - - Tunnel alignments have been selected (see Plate VII and IX), nearly normal to the strike of the bedding, which should be favorable for tunneling operationso It is expected that overbreak can be held to less than five percent as it was along the tunnels of the Alaska Railroado 4" Comoarison of Cooper Lake Tunnel with Other Tunnels in Similar Formations. 1Vhittier Tunnels Two tunnels for a total distance of about three miles were driven to construct the Portage-Whittier Branch of the Alaska Rail- road. These penetrate formations which are similar or identical to those at the Cooper Lake TunneL The strike and dip of the beds have almost the same relationships to these tunnels as they will at Cooper Lakeo All of the rock types can here be observed -the slates, gray- wacke, and finely fissile slate. Only the finely fissile slate de- teriorates or air slacks o In these railroad tunnels where the fissile slate has been exposed to air since 1946, a layer two to three inches thick has softened so that it can be cut off with a pick" Beneath this thickness, the slate is sound and hard" The Whittier Tunnels stand unsupported except for short sections at the portals and two or three short sections (less than 700 feet in 3 miles) where sheared zones were crossed" Minor amounts of ground water were encountered in the 300 to 400 foot portal zones, but throughout the remainder of the tunnel, ground water seeps are insignificant" It is expected that rock conditions at Cooper Lake will be generally similar, and anyone concerned with the Cooper Lake development should make an in- spection trip through the Whittier Tunnels. Eklutna Tunnel The difficulties in driving the Eklutna Power Plant Tunnel were reported on by Geologist \-Jilliam Ro Judd in Separate No. 444 of the Proceedings of the American Society of Civil Engineers, June, 1954. It is interesting to note from the report that the heavy flows of ground water encountered in the early stages of tunnel excavation were predicted by surface geologic studies o Mr. Judd also made pre- liminary studies at Cooper Lake and has made the following comparison of geologic conditions at Eklutna and Cooper Lake. (From personal correspondence with ~~. He Irwin, Chief Geologist, U. So Bureau of Reclamation, Denver 9 Colorado, August 12, 1955.) liThe graywacke at Cooper appears much more competent than the graywacke at the ends of the Eklutna Tunnel. Except for occas- ional faults it probably is more nearly represented by the very com- petent graywacke encountered in the center one-third of the Eklutna F-13 PORTt.ANO • OREGON NOR T H P A ( I F I ( ( 0 N 5 U l TAN T 5 ANCHORAGE, At.ASI<;A - /" - • • • • • • .. - - • - - Tunnel: steel supports were not required in this portion of the tunnel. II D. CONDUIT Between the two tunnel sections, the conduit will cross a rugged terrain of bedrock and shallow surficial depositso The posi- tion of these features is shown on Plate VII and details on Plate IX. Because of the heavy cover of moss, muck, alders, and other shrubs, no attempt has been made to detail the geology on the map. The ge- ology that could be secured from examinations along the cleared lines of the original conduit line and from 35 probings is shown on Plate IX. The results of the probings are also tabulated on Plate VII. Studies and reconnaissance indicated that the average depth to bed- rock in the general area of the conduit will probably average between 5 and 10 feet in deptho Bedrocks along the conduit line are alternat- ing slates and graywackeso It appears that suitable foundations for pipe anchors can be found almost any place along the line. E. PENSTOCK The penstock crosses a relatively steep and rugged terrain of bedrock and shallow superficial depositse The position of these features is shown on Plate VII and details on Plate IX. Photo No. 11, Plate "F-ll", shows the location of the penstock on this slope. The geology that could be secured from examinations along the cleared line and from probings are tabulated on Plate VII. Studies indicate that the depth to bedrock will probably average about 5 feet. Excellent foundations for the pipe and for the anchorage thereof can be found any place along the penstock. F. POWER PLANT A location for the powerhouse has been selected where the structure will be founded on bedrock. (See Plate "F-U", Photo No. 11). The rocks are of excellent quality graywacke interbedded with minor amounts of slateo The formation strikes N. 10 to 15 degrees E., and the dips are nearly vertical. The rocks were investigated by field examinations and the putting down of two blast holes so that visual inspection could be made of fresh exposures and samples taken. A 500 pound sample was taken from the powerhouse area to test the suitability of the rock for crushing and processing into concrete ag- gregate. Samples of the rock at the powerhouse (Nos. 6 and 15) are available for inspection in the office of the Central Alaska Power Association in Anchorage o Test of this material is as follows: F-14 POFtTLANO • OFtEGON NOR T H PAC I fIe CON S U l TAN T S ANC;HORAOE. AL.ASI'\A - - • .. .. .. .. .. .. III • Report on Aggregate Test and Investigation 15 November 1955 DE Lab No o 431 Sample: Rock to be crushed Location~ Cooper Lake Power House Site Test Results The sample was crushed to maximum size of 1-1/2". The results given below are on the crushed sample • 1. Sieve Analysis (ASTM Designation C 136-46) Sieve Crushed Size Sample 211 1-1/211 100 1" 64 3/4" 34 1/211 21 3/811 16 No o 4 9 Noo 8 3 Noo 16 2 Noo 30 1 No o 50 1 No. 100 1 -3/8 Haterial put through a roller Percent Passing 100 94 63 48 28 14 2.. The manufactured sand fracture was washed over a No. according to ASTM Designation C 117-49. 200 sieve • Percent Passing 10 - - - • - - 3. Specific Gravity and AbSOrption (ASTM Designation G-127-42) Bulk Specific Gravity, S,S4D. Apparent Specific Gravity Absorption, percent 4.. Abrasion of A nation C 131-1 Grading "BII, percent loss F-15 2.72 2 .. 74 .4 (ASTM Desi - 2.6 Porm ... NO • OIl!:CJON N 0 RT H P A CJ Fie CON S U l TAN T S ANCHOR ... GE, AI. ... SK ... - .. .. .. • • .- • .. til - - - • - - 5. Soundness of Aggregate Using r1agnesium Suluhate (ASTMDesigna- tion C 8B-46T) Percent Loss, five cycles 6. Unit Weight of Aggregate (ASTM C 29-42) Unit Weight Dry Rodded Unit Weight Dry Loose 70 Alkaline Reactivity Test (ASTM Designation C 227-52 T) Reactivity test showed slightly deleterious. Noteg A low alkaline cement should be used in the mixo The crushing of the aggregate indicates that an accept- able aggregate could be manufactured from the rocks submi tted. However an extra amount of waste would be encountered because of the high percentage of minus material that would be accumulated in the crnshing process. W" M. KNOPPE Chief, Testing Section There is no evidence in the field of snow slide activity in the vicinity of the powerhouse or in nearby areas with a similar topographic setting. The clearing for the penstock could conceivably encourage the development of minor snow slides parallel to the pen- stock, but no other activity need be feared. Go EARTHQUAKES The Kenai Peninsnla is a strongly active seismic area. Many earthquakes have been recorded, the most recent severe shock on October 2, 19540 The Cooper Lake Valley lies in a northwest- southeast direction, parallel to many of the main valleys near the project area. These parallel valleys no doubt reflect a part of the major structural system and probably follow faults or sheared zones in the highly folded rock structure. Investigation of earthquake results at Upper Russian Lake suggests that some of the faults in the area are somewhat active. F-16 PORTLANO • OREGON NOR T H P A ( I F I ( (0 N S U l TAN T S ANCI-!ORAGE. AL.ASKA - -, • .. • .. • • • .. • • -- - • - - The earthquake of October 2, 1954 displaced the shore line at the outlet of Upper Russian Lake 12 to 18 inches in elevation and set off many landslides, one of which nearly caught some hunters camped at the upper end of the lake. The area of the Cooper Lake Project is closely equivalent in seismic activity and probability to the state of California • Many projects of the type considered have been constructed in Cal- ifornia and operated successfully for many years. No failures due to earthquake damage have been experienced. Even so, the possibil- ity of seismic activity should be considered in designing all fea- tures of the project • IV. REGIONAL GEOLOGY It is not within the scope of an investigation of this type to attempt to work out the complex regional geology of the area. Consequently, the research reports of other workers provide the best available understanding of regional rock relationships, structure, and history. Actually, the regional geology is usually of little interest on projects such as this except to the geologist whose job it is to interpret the foundation conditions at the con- struction siteso The regional geology of this area is well sum- marized by Ralph Tuck in Bulletin 849-1, United States Geological Survey -The Moose Pass -Hope District, Kenai Peninsula, Alaska. His summary is not an individual one but represents a summary of the work of many geologistso For those who are interested, parts of the regional geology relating to Cooper Lake Project are here extracted. A. GENERAL GEOLOGY Principal Features The rocks of the area are predominantly interbedded slate and graywacke, which Mendenhall 3 originally termed the tlSunrise Seriesl!o They comprise over 95 percent of the bedrock exposed and everywhere are highly folded and faulted. Attempts to subdivide them and work out the structure and stratigraphy L~ detail have proved unsuccessful because of their lithologic similarity. The only other noteworthy formations are the unconsolidated postglacial gravel deposits, which are widespread, occupying the F-17 PORTLAND. OREGON N 0 RT H P A ( If I ( ( 0 N 5 U l TA N T 5 ANCHORAGE. ALASKA - .' • • .. • • • • - •• - - - - - bottoms of all the valleys and at many places occurring on the valley walls as terraces or benches. B. STRATIGRAPHY Slate and Graywacke. Distribution and Character The interbedded slate and graywacke are almost everywhere abundantly exposed except in the northwest corner of the district. As a whole the unit consists of almost equal amounts of slate and graywacke, although locally one type may predominate over the other. *** The slate is gray to black, is fine grained and usually shows cleavage, though the cleavage is rarely so good that the slate could serve as a roofing material. Locally the slate may be foliated, either owing to greater pressure or to a larger proportion of im- purities, so that it might more properly be termed a schist. The more massive portion of the slate should be termed argillite. The slate occurs in beds and lenses from 1 inch to over 100 feet thick. Microscopically the slate is very fine grained and is composed of small rounded quartz grains, oriented sericite flakes, and kaolin. Accessory minerals are rounded feldspar grains, irregular masses of calcite, and chlorite. Cleavage, folding, and faulting are conspicuous in the thin sections. The graywacke differs from the slate in that it is coarser grained and contains more quartz. It occurs in varying shades of gray and gray-green, and in only a few localities is it clean enough to be called quartzite. The texture ranges from fine to coarse. Individual beds are lenticular and cannot be traced far along the strike without varying in thickness or pinching out. The range in thickness may be from a few inches to several hundred feet. They occur interbedded with the slate or in massive bodies and show schistosity, cleavage, and joints, but not in the same degree as the slate. Under the microscope the graywacke is seen to be composed chiefly of subangular grains of quartz and orthoclase and plagioclase feldspar. Accessory minerals are calcite, hornblende, chlorite, seriCite, kaolin and pyrite. Interbedded with the slate and graywacke and of only local extent are lenses of conglomerate, lL~estone, and greenstone. It is doubtful whether they comprise more than 1 percent of the slate and graywacke mass. Locally the conglomerate may be sheared and the pebbles stretched out, but usually it is massive. F-18 PORTI.AND • OREGON N 0 RT H P At I Fie CON S U t TA NT S ANCHOFt .. GE. AI.ASKA - /" _I - • III • .. III .. III • ,. - - - - Origin The slate and graywacke beds were originally laid down as clays sand, limy sediments, and gravel in a basin of deposition com- parable to that of many of our present shallow seas. Proof of their sedimentary origin is plainly apparent in the bedding or stratifica- tion~ the composition and the occurrence here and there of fossils in similar formations in adjacent districts. Subsequent to deposi- tion the beds were consolidated and uplifted, as a result of great pressure, which metamorphosed the graywacke into its present indur- ated condition and produced cleavage and foliation in the more clayey rocks. The metamorphism, however, was not so great as to destroy their original sedimentary characteristics. To give the present re- peated alternation of slate and gray>iacke, conditions during their deposition must have been such that there were almost rhythmic re- curring cycles of sedimentation. As the sediments are probably at least 5,000 feet thick, the basin of deposition must have been gradually sinking, although with minor fluctuations. Age and Correlation Although the slate and graywacke of the Moose Pass-Hope district is part of a series that is regional in extent, their4a ge is difficult to determine, as fossils are scarce. Mendenhall, Johnson,5 Capps,6 and Landes 7 have shown the similarity of this series of rocks from Resurrection Bay to the Matanuska Valley • Mendenhall, in calling it the "Sunrise Series", placed it as pre- Cretaceous and 9 tentatively) as Paleozoic, in view of its associa- tion with the Cretaceous of the Matanuska Valley. He also suggested that it may be a part of the Valdez group of Prince William Sound~ which had been placed tentatively in the Paleozoico Johnson and Martin,8 from a few fossils collected at the head of Crow Creek, in the Girdwood district, considered its age to be Jurassic or Creta- ceous o Reeside~ through his identification of fossils collected by Park9 in the Girdwood district, believes it to be definitely Cre- taceous and probably Upper Cretaceous. Stratigraphically and lithologically the metamorphic rocks of the Moose Pass -Hope dis- trict are similar to those of the Girdwood district, and there is no reason to think that their age is different, or other than creta- ceous. ** ** 2. Unconsolidated Deposits. Principal Features The unconsolidated or only partly consolidated deposits consist of clay, sand, gravel and boulders and constitute over one F-l9 PORTI.ANO • OREGON N 0 RT H P At I F ICC 0 N S U l TA N T S ANCHORAGE. AI.ASKA - / - .. • • • • • • • • • - -- - - third of the surface exposures. They directly overlie the inter- bedded slate and graywacke and the volcanic series in the valleys and on the valley slopes. No unconsolidated deposits of preglacial origin are known to exist, and probably the glaciers that occupied the valleys during Quaternary time eroded and transported the earlier' stream deposits. The unconsolidated deposits may be classified in- to three groups -(1) glacial deposits consisting of unstratified clay, sand, pebble, and boulders deposited directly by the melting glaciers; (2) glaciofluviatile or bench deposits, consisting of stratified and unstratified clay, sand, gravel and boulders de- posited by water from the melting ice and made up mostly of reworked glacial material; (3) recent deposits, consisting of clay, sand, gravel and boulders deposited by the present streams. In addition to these three types there are some small lake deposits, but as they are of slight areal extent and of no economic importance, no further mention of them will be made. Glacial Deposits . Few extensive glacial deposits remain in this district. Glacial till consisting of a dense clay in which angular pebbles and boulders are embedded is present in some of the stream valleys and rests directly on the grooved and polished bedrock ••••• The lack of glacial deposits in this highly glaciated region is due to the tremendous amounts of water released from the melting glaciers, which, having been concentrated in the glaciated valleys, reworked all the previous unconsolidated deposits. Glaciofluviatile or Bench Deposits . The glaciofluviatile deposits constitute the greater part of the unconsolidated material in the district. They consist of clay, sand, gravel, and boulders, usually stratified, although in places only partly so. Locally they may be slightly cemented by 1ron oxide or calcium carbonate. Their distribution over the re- gion is widespread. Some form benches or terraces that are as much as 2 miles wide and extend the entire length of the stream. The benches slope toward the middle of the valley and downstream. Their formation began at the end of the active glacial epoch, when enormous quantities of water from the melting ice reworked and de- posited the material that had been left by the glaciers ••••• Many of the bench deposits originated as deltas and alluvial fans and are particularly conspicuous at the points where the tributary streams emerge into the valleys of the main streams. These post- glacial deposits range in thickness from a few feet to several hundred feet, the thickness depending on the topography of the valley prior to their deposition. F-20 PORTLA"'C , OREGON NOR T H PAC If JC CON S U l TA N T S ANCHORAGE, ALASKA - - • .. .. • • • • .. ... - .. .. .. Recent Deposits The recent unconsolidated deposits are found in the chan- nels and flood plains of the present streams wherever they are ag- grading. This material consists of clay, sand, gravel and boulders, and the greater part of it represents reworked bench gravel, as the most of the main streams are still actively cutting in the glaciofluviatile depositso C. STRUCTURE The consolidated rocks exhibit a highly complex structure, as they are everywhere intricately folded, and the lack of any con- spicuous or recognizable formation makes interpretation difficult. The monotonous character of the interbedded slate and graywacke succession prevents easy recognition of the broader aspects of the structure, and only small details can be gathered and pieced to- gether. The general structural trend is No 10 0 E. 16. The dip is usually steep1 ranging from vertical 20 0 or 30 0 either east or west. It is difficult to account for this large area of steep dips by thickness of formation alone, as this would call for an incredible thickness of almost identical formations. A more plausible assump- tion is that there is repetition of beds, caused either by isoclinal folding or by a large number of strike faults. Both folding and faulting have caused this apparent great thickness of formation, as in small outcrops isoclinal folds are common as well as small strike faults. The axes of these isoclinal folds may be steeply inclined either to the west or to the easto L Cleavage. Rock cleavage is widespread throughout the slate and gray- wacke. The effect of the competency of the rock on the development in the slate, which is less competent than the graywacke, but also by the fact that in the slate the cleavage is closely parallel to the bedding, whereas in the graywacke, it is widely spaced and at larger angles with the bedding. As a whole, the cleavage closely parallels the strike of the beds. The effect of the relative com- petency of the rock on the structural features produced is apparent on a small scale where the slate and graywacke are exposed side by side; the slate is folded and the graywacke is faulted. This suggests that the same effects might be produced on a regional scale. 2. Joints • Well-developed joints are found at localities scattered throughout the region. The best-developed set has a general east- west strike and a vertical dip. They are smooth, clean-cut, typical F-21 POFlTf..ANO • OREGON NOR T H P A ( I F r C (0 N S U l TAN T S ANCHORA"!. Af..ASKA - • • • .. .. • • • -- • • - - shear joints, usually spaced at intervals of 6 inches to 2 feet. A poorly developed set striking northeast is represented in a few places. The well-developed set of joints may show minor horizontal movement, causing a cellular structure in quartz that apparently had been deposited in the joints prior to the movement. Faults. Faults are one of the most common structural features of the-district" No large faults of regional extent were recognized, and it is believed that their absence is explainable by the presence of numerous faults of small displacement. It is probable that much of the relief from stress was accomplished through the small faults • The aggregate displacement of these small faults would be sufficient to account for the apparent repetition of formations o D. GEOLOGIC HISTORY The geologic history of this district is probably similar to that of the Chugach Mountain province, of which it is a part, and will be given here only briefly. 1. Pre-Tertiary. Of the pre-Cretaceous history nothing is known, as there are no rocks of probable pre-Cretaceous age in the district, unless the volcanic series west of Hope should prove to be pre-Cretaceous, which seems unlikely. However, as their age is not known at present, it will be sufficient to say that the volcanic rocks represent a period of intense volcanism during which ash and rock fragments were showered down upon a low-lying area, a portion of which was covered by water, as the nature of some of the tuffs suggests deposition in water. Probably during the later part of the Cretaceous period the area was submerged beneath the sea, and streams flowing into the sea deposited a great thickness of sediments, which have formed the interbedded slate and graywacke of this report" That there were frequent fluctuations of this sea level is suggested by the alter- nation of beds of slate and graywacke, with scattered lenses of limestone and conglomerate, but in general this basin must have been gradually sinking in order to accumulate so great a thickness of sediments" After the deposition and consolidation of all this material it was subjected to enormous pressures, which resulted in the folding, faulting, and uplift of these sedimentary depositso During this time of stress the shale and sandstone were changed and altered to the present slate and graywacke. The direction from which this stress came is not exactly known, but the north-south strike of the cleavage and folds in the district and the arcuate trend of the entire Chugach Mountains suggest that it might have been from the F-22 PORTLANO • OREGON N 0 RT H P A CI Fie CON S U l TA NT S ANCHORAGE. ALASKA - • • • • • --- • - - - - - east and southeast. It ''las not a simple, direct stress, but probably a differential movement, continually changing in direction and point of application. The last phase of this mountain-making movement was char- acterized by the intrusion of the acidic dikes; only minor movement occurred after their formation, as they are only slightly fractured and folded o After the fracturing of the dikes mineral-bearing solu- tions emanated from the still molten underlying magma and were de- posited in fractures and fissures~ forming the present veins and mineralized dikes. Since this period of mineralization some deform- ation has taken place. This deformation was widespread, although slight in magnitude, as the veins and mineralized dikes are only fractured and sheared, having suffered little or no displacement. 2" Tertiary" During the Tertiary period erosion progressed vigorously" It is probable that the whole region was reduced to base level and later uplifted, but the only evidence of this peneplanation lies in the partial concordance of the ridge and mountain tops" The lack of Tertiary deposits prevents the further deciphering of the Tertiary history. 3" Quaternary. At the beginning of the Quaternary period the topography was much like that of today, being mountainous and having drainage, in general, along lines similar to those of the present time e Oli- matic changes resulted in a yearly increase and excess of snowfall. The snow, becoming compacted into ice at several centers in the higher portions of the mountains, formed glaCiers, which gradually. moved down the slopes as a result of the increasing pressure behind. The valleys were thus filled with ice up to an elevation of 4,000 feet. Later other climatic changes caused the melting of the ice and the retreat of the glaciers. The chief action of the moving ice was to gouge out the valleys and smooth the slopes up to an elevation of 4,000 feeto Above that height the mountains are unglaciated and are rough and rugged, chiefly from mechanical disintegration. The preglacial V- shaped valleys were broadened to U-shaped valleys, ridges were truncated, many of the valleys tributary to the main streams were left as hanging valleys, and the bedrock was scoured and polishedo The water liberated from the retreating glaciers reworked much of the glacial debris and deposited it as bench gravel. Although there may have been several advances and retreats of the glaCiers? this area shows evidence of only one such movement. At the end of the active glaciation the streams renewed their courses, and since that time they have been engaged in cutting and reworking the gla- cial outwash material. In a few places they have removed it entirely F-23 POATI.ANO , OREOON NOR T H PAC I fie CON S U l TAN T S ANCHORAOE, AI-ASKA • • • • • • / ,3J • .. - , .. -. - - - - and are cutting in the bedrock, but most of the streams have not com- pleted the removal of the unconsolidated cl~, sand, gravel and bou.lders .. E. BIBLIOGRAPHY 3. Mendenhall, W .. C., A Reconnaissance from Resurrection Bay to the Tanana River, Alaska, in 1898; U. S. Geol. Survey Twenti- eth Ann. Rept., pt. 7, pp. 305-307, 1900. 4. Mendenhall, W. C., Ope cit., pp. 305-307. 5. Martin, G. C., Johnson, B. L., and Grant, U. S., Geo- logy and Mineral Resources of Kenai Peninsula, Alaska: U. S. Geol. Survey Bull. 587, p .. 27, 1915. 6.. Capps, E. R., The Turnagain-Knik Region, Alaska: U. S. Geo. Survey Bull. 642,pp. 155-161, 1916. 7. Landes, K. K., Geology of the Knik-Matanuska district, Alaska: U. -So Gaol. Survey Bull. 792, pp. 56-57, 1927. 8. cit., p. 118. Martin, G. C., Johnson, B. L., and Grant, U. S .• , op. 9. Park, C. F., U. So Geol. Survey Bull. 849-G, p. 393, 1933. F-24 PORTLAND, OREGON NOR T H PAC I Fie CON S lIl. TAN T S ANCHORAGE, ALASKA - v. PHOTOGRAPHS • • .. • .. .. • • - - -.. - -PORTLAND • ORIlGON N 0 RT H PAC I Fie CON S U l TA N T S ANCHORAGIl. ALASKA I I • • • • • • a • • I • Photo No. 63 Rock quarry near the mouth of Cooper Creek. The rock formations quarried here are interbedded slate and graywacke similar to the formations in the left abut- ment area of the damsite and similar also to the formations in the tunnel area between Stations 12+00 and 25+00 and between Stations 32TOO and 45+00. September 15, 1955 • I , I ~) , • • I , • • • , • • • , I Photo No. 42 Cooper Lake and Reservoir Basin 6S seen from the high switchback on the cat trail. Damsite Atea in lower right hand corner. Cooper Mountain upper central right. Kenai Mountain in left background. August 29, 1955 I I 1 0 -• I I I .. • • I Ii ~ \J\ • • I • Photo No. 7 Ridge between Cooper and Kenai Lakes through which tunnel will be driven. Ridge consists of slate and graywacke formations in a nearly vertical position, striking in approximately the direction the aerial oblique photograph was taken. Cooper Lake at left, Kenai Lake at right and in background. July 25, 1955 I I • 0 • , I , , • • • • • Iii • • Photo No •. 31 Aerial oblique view showing the southwest end of Cooper Lake and the ridge between the Cooper Creek drainage and the Russian River drainage. August 6, 19.5.5 • I - • • • • •• • • - -- • - - Photo No. 49 Thin bedded blue-black slate with occasional thin beds or lenses of graywacke. Rocks of this type will be encountered in the Tunnel between Stations 0+00 and 12+00. For exact location of photograph see Plate VII, Geologie Map of Tunnel, Conduit, and Powerhouse Area. August 30, 19.5.5 NORTH PACIFIC CONSULTANTS Plate F-.5 I '0' I • I • • • • • • • • • Photo No. 48 Interbedded slate and graywacke. The slate is blue-black in color, and beds range from 1/8 inch to 4 inches in thickness. Tbe graywacke 1s light gray in color and in this ex- posure forms the ridges between depressions marking beds of slate. Rocks of this type will be encountered between Stations 12-00 and 26-00 and between Stations 32-00 and 45-00. The location of this photograph is shown on Plate VII, Geologic Map of Tunnel, Conduit and Powerhouse Area. August 30 , 1955 I • • o· z 0 ~ ,1 ~ 'U f) j' f .. ," H ~ Q Q 0 ,r' tJj fi 5 ~.' , '(,:1' , 'j',;;" " , ,. ' . I • , I • • • • • • • • • ., :"1 l ' '~ ", " ",~ • ~¥> .-' ," , / , Photo No. 54 Detail view of interbedded slate and graywacke. The slate is blue-black in color, the graywacke forming the lighter colored bands. Note extreme tightness of bedding planes between rock types. Rocks of this type will be encountered in the Tunnel between Stations l2~00 and 25+00 and between Stations 32+00 and 45+00. Exact location of photograph is shown on Plate VII, Geologic Map of Tunnel, Conduit and Powerhouse Area. August 30, 1955 • u ~ o u o u u u u ~ U u':& U Photo No. 52 Joints and small faults in graywacke formation. Photograph was taken of a bedding plane surface which had been exposed to wave action, etching out the joint and fault pattern. Graywacke of this type is found in the interbedded slate and graywacke formation between Stations 12+00 and 25~0. For location of outcrop see Plate VII, Geologic map of Tunnel, Conduit and Powerhouse Area. August 30, 1955 NORTH PACIFIC CONSULTANTS Plate F-8 Photo No. 57 Steep anticlinal fold in interbedded slate and'~~aywacke formation exposed along the shore of Kenai Lake. Rocks of this type will be encountered in the Tunnel between Stations 12+00 and 25+00 and between Stations 30+60 and 42+00. For exact location see Plate VII, Geologic Map of Tunnel, Conduit, and Powerhouse Area. September 12, 1955 ------------------------------------------------- Photo No. .51 'Detailed view of texture of g~ywacke: at Blast Hole No.6. Rock formations of this type Will be encountered in the tunnel between S~ations 26+00 and 32+00 and between Stations 45+00 and .56+00. The exact location of this photograph is shown on Plate VII. Geologic Map of Tunnel, Concuit~ and Powerhouse Area. , August 30. 19.5.5 -~~~------- c: Photo No. 11 Aerial oblique of Powe~house. Penstock and Surge Tank Area, Cooper Lake Project. . July 25. 1955 u Cb· u u" W J U ,u I 'W I jlf) U I U U U U D ! U lJ0 U VI. SEISMIC SURVEY PORTLAND, OREQON NO RI H PA C I F IC CON S U L TAN T S ANCHORAQE, ALASKA J ~. j J J J J J J SEISMIC SURVEY' OF THE; COOPER LAKEDAMSITE FOR THE CENTRAL ALASKA POWER ASSOCIATION I. INTRODO'rnON A._ LOCATION . Cooper Lake is located on the Kenai Peninsula, Alaska at approximately 00 0 25 1H Latitude, 1490 47'W Longitude. The damsite area is' located at the northern end of Cooper Lake. A viCinity map, location, plan and detail map ot the damsi te area are shown on Plate 10 Th~ axis of the proposed dam cuts across Cooper' Creek about 400 feet downstream from the outlet of the lake. B. PURPOSE AND SCOPE . The purpose of the survey was to investigate the sub- . surface foundation conditions exi'sting in the damsi te area as well as to locate possible sources ot borrow materials. Information as to the depths to the major changes in .subsurface strata, general character of the: strata and their areal extent was desired. c. AUTHORIZATION This survey waS made for the Central Alaska Power Associ- atj,on at the request of. the. North Pacific Consultants. Verbal . authorization for performing the work was given to Mr. D., E. Reed, Seismologist, Gahagan Construction Corporation by Mr. Marlin Stewart,. Acting Manager, Central Alaska Power Association on July 25, 1955. II. GENERAL- The seismic work at-Cooper Lake began on August 3rd and was completed on August 12, 1955. The bulk of the survey was con- centrated in the damsite area. Single spreads were' shot along the -1- PORTLAND, OREGON' N 0 RT H PAC IF ICC 0 N S U L TA N TS ANCHORAGE, ALASKA J ( 1 u 'U I jU ! 'U IU D ,w I ( 'rO U U· tunnel line and along an alluvial fan on the west 'edge of the lake. Two spreads were shot on the, alternate dam axis. Plate 1 shows the general location of the four areas surveyed. The location of the seismic lines in the damsite area are shown on Plate 1... In all, a total of 10,260 lineal feet of contin- uous profiling was' performed in six working days. Two field days were lost due to inclement weather. ,. Intermittent light rain was a daily occurrence while the seismic crew was in the field; consequently moisture and its effect on equipment operation was an important consideration. To insure against loss of time due to equipment malfunctioning, a, special dry- ing-rackwas built and the equipment was placed on 'this rack immed- iately after each day of field work. Should any .future seismic sur- veys be made in this area,9 equipment with hermetically sealed com- ponents would be used. III. RESUL TS The subsUrface profiles are given on Plates 2, 3 and 4 .. Elevations, where shown, were .furnished by the survey crews of the North Pacific Consultants.. Seismic velocities for the various strata recorded have been included on the individual profiles. Where lateral changes in surface velocity occur along an individual line, the average velocity at each end of the line has been indi- cated.' In a few instances where the data was insufficient for an accurate depth determination, a minimum depth has been calculated . and is indicated on the profiles by a dashed line. The area was well ,suited to a subsurface investigation by the seismic method.-The velocity contrasts between the various strata were good and the energy transmission characteristics were excellent. Interpretation of the seismic data shows three msjor strata to be present in the damsite area. 'The average seismic velocities recorded for these three strata were 1,800 feet/sec., 6,000 feet/sec., and 14,000 feet/sec., respectively. These velo- cities are characteristic of a sequence consisting of loose sand and gravel overlying till or hardpan which, in turn, overlies bed- rock._ Seismic lines shot from test· pits and borings for the purpose of correlation checked out very well. As an example, see Section B-A t shown on Plate· 2. This line was shot"frdm the edge of Test Pit No.2 on the right abutment .. The seismic: data indicated -2- PORTI.ANO • ORCGON N 0 RT H P A CI Fie CON S U L TA N T S ANCHORAGE, ALASKA D U IW I u U D I~ I 17 feet of loose sand and gravel overlying a compact material prob- ably till. The actual test pit showed 16 feet of stratified sands and gravels overlying a modified till. DER/e -3- GAHAGAN CONSTRUCTION CORPORATION Geophysical Survey Division sl roNALD E. REED .il:>nald E. Reed Project Seismologist PORTI.AHD • OIlItIlON N 0 IT H PAC I Fie CON S U LT ANT S AHCHORAOIt. ALASKA NATioNAL FOREST PLAN OF DAMSITE AREA SCIoLi: IIHCH. 200 'EU I I WUT ALLUYIAL- 'AN IBORROW LOCATION' kENAI PENINSULIl ~,,~, ,,,,, .. "" LOCATION Pl AN SCALI! 'INCH-"MILU • 01 !! -I'----~-----..!l_e2° VICINITY MAP SCALE lINCH. 40 MILES GAHAGAN CONSTRUCTION CORP. GEOPHYSICAL SURVEY DIVISION 90 BROAD ST.,NEW YORK 4,N.Y. SEISMIC SURVEY COOPERS .lAKE DAMSiTE KENAI PENINSULA, ALASKA SCALES AS SHOW .. PLATE I • • • .. o t . • tOO .t"" SECTION Q-.I H 01. •• '8 .tOO 1.00 ItOO n'I.r1-r-r"T'"T""'1r-T-r-r--i-"r-T-r-i-'-T""I"'"l""OO i-.. ... ... Ii! ., a 2 '.IIOi-nn""T,..,.-;-nn-r.,-T''T""r"'''Ir-T ............ ~.,....;:....~,....,,,o ~ Ilotttt;j~; ... .J ... tn' PI! No.f .,00 Encoun .... CO .. t~i±ttltijit:t:ttljll:I~tdt:t±tJPoc:, MOf,dot 1ft pn at us: OtOO OtOO SECTION M'-t. GAHAGAN OONSTRUOTION OORP. GEOPHVSICAL SURVEY OIVISION 90 "'lOAD St .... ! .. TOI'IK 4,II.Y. SEISMIO SEOTIONS RIGIlT A8UTMENT COOPERS LAKE OAMSITE KENAI PENINSULA,AlASKA 'CALI' A' IMO •• . --.~~ ... -------------.----------_ .. -_ .. _---------- • • • 0- W ~ !! 5 G t,OO '1'0 tlOO U!lO OtOO 5> 101M WI 1110 ... .. ... .. .. .. !! '" Ii: .. '" 1.00 UIO 0.00 l II # • m I 0 , ~. I ......,.. 0 .. I I HOO ItOO • 100 '.00 "00 SECTION G-JHR~ ABUTMEIm I.L I!~. • 2 1 ~ .. "00 ji. 1 noo ItOG ,.00 SECTION MM-kk (RIGHT ABUTMENT! NN 00 • j.. .. .. .. oj ! z Ii: I: , .. 00 .. 00 ,.00 .'00 100 $lcnON PP-OO ALTERNATE DAM AXIS IBORROW LOCATION' • t .. ... TT 0 -I I /$. .too , . 00 A '$1IMfl/ Hl1I'irtJMDI S.,fllc, I J f. SS o .. 00 t-o. .. .. ~ '0 10 ! t o. D 1 ~o 00 0.00 noo '''00 t .. o SECTION n-ss WEST '1.i.~~IA~_~AN !lORROW I.OCATION! ... ... ... .. ! '" ... ... !l 3tl0 ~o t-I-H-H4-I-+f.- ~\'~.o~o~~~~~~~~~-LJLlJLl-LjLl-LJ,oo "00 ,!!,CTlON 0.90-3.'0 TUNNEL LINE 0-o. ... .. ! t ~ 1/1 oIJ 500 1 ItI'_ I;; I ISo ~ ! lI! S? I ~ too .., " I. ... o. GAHAGAN CONSTRUCTION CORP, GEOPHYSICAL SURVEY DIVISION . 90 II"OAO ST.,NEW YOllo( 4,1I.'t SEISMIC SECTIONS COOPERS LAKE OAMSIT[ KENAI PENINSULA, ALASKA .... HH-+++-H-+++t-IH-+++t-IH-+++-t-IH-+++-+-- OtOO ItOO 229'Le" '''~''''T'''1I""T..,..,...,...r- 88 .... 10'Uf' IlZ'LeU .... ftOO SECTION 7tOO "00 '.00 cc .I! i" 'tOO-!! "0'0 j .... :, ,,'0 t.oo '" ') ~ . • ,"Ufl ••• 3S'Lefl 1110 •• 10 t:!I~;f"t-ot:-H-+++HH-+++t-IH-+++-H-+-J""o I···H-++-I-Hi- ulO ........................ '-'- etoo • ItOO SECTION 8tOO ••• I: cZ~ ItOO '011 • 1+00 SECTION 8tOO flOO SECTION t: <; \ .",+l,f'::'l_",*~.,.~I" .. _I," • ~------~ .. --~.--~ .. ---.~------------- -. "00 litO "'00 10.00 \llelnll; of D,K"I '100 140'Saul" 10. I IUto (J'() .011# OtOO • .tOO .. to .. .. .. .. ! SECTION NEAR DRILL HOLE MO.; ~ ;:. , Of oJ Of GAHAGAN CONSTRUCTION CORI GEOPHYSICAL SURVEY DIVISION 90 9110AO ST.,IIE. YOR~ ",N.Y. SEISMIC SECTioNS LEFT ABUTMENT COOPERS LAKE DAMSITE K!NAI PENINSULA,ALASKA ICALit At IMo-._ PLATI LJ D ~ D o o U J U u lb u J J rl U U D o ~Q u APPENDIX II Gil HYDRAULlC ANALYSIS PORTLAND. OREGON N 0 RT H PAC IF ICC 0 N S U L TAN IS ANCHORAGE. ALASKA- o u u u u u u U D I. II •. OONTENTS Hydraulic Analysis General Project Plan A. Prior Investigations' and Reports - --. - - --. - - -G-1 B. Preliminary Plans - - - --. -. - - - - - - - - - - -G-1 C. Project. Investigations --- -_. _. -------'--G-3 1. Plans Studied -_. --. - - - - - - --. -. -. - --. G-3 2. Cooper Creek Dam -. - - - - --, - - - - - - - - -G-3 3.· Tunnel, Conduit and Penstock - - --. - - - - - -G-4 4. Powerhouse _. -. --.---. -_. - - - - - - - -G-5 D. Ptarmigan Creek Diversion -. - - - - - - - - - - - -G-5 Installation Features A.. Dam -. -" --. -. -. --. -. --, -. -. -. - --. - --. - - - -G-6 B. stream Diversions During Construction - - - - - - -G-. 7 c.. Spillway--_. -. - --" - - - -_. -...; -. -_. --. - --, -. G-7 D. Reservoir-_. _. -. -. -, - --. - --. -. --. -_. - --" --G-8 E. Power"Intake -.---.---. -. --. --. - - -_._. -_._,G-, 8 F. Tunnel and Condnit - - - - - --. -. --- - --. --,-, G-9 G... Surge Tank --. -. --. - - --_. -. -. -, -,._. -. --. -. -. -. G-10 H~ Penstock -_. --, --, - - -_._, --. -_. - - - --,--.G-10 I., Scroll Case: and Draft Tube - - --. - --, - - --. --,G-ll J. Tailrace --. - - - --, --'. -. -. -. _. -' -.. -. --" -. -, -. -. G-ll III. Power Available A. Basic Power' -. -_. -. - _ .. -, --' -. _. -, -. -.--. - - -.. -. G-ll B. Peaking Capacity --, - - - - - -_._, - - - - - --, -G-12 C. Heads - --. - -----.-- - - - --.-- --·-G-13 D. Flow and Power' Duration -. -. - - - --. - - - - - - -G-14 PORTLAND. OREGON NOR T H PAC I F I ( ( 0 N S U L TA NT S ANCHORAGE. ALASKA n W u D , (' w 'U I U ( \ LJ U IU :0 o t, CJD U - I. GENERAL PROJECT PLAN A.. PRIOR INVESTIGA nON AND REPORTS The Cooper Lake project has been previously studied by agencies of' the Federal Government and by Chugach Electric .Associa- tion, Inc. These reports and investigations are as f'ollows: 1. "Interim Report No.1, Cook Inlet and Tributaries" prepared by the Alaska District, Corps of' Engineers. (Jan. 20, 1950) 2. Geological surveys by the U. S.Geological Survey re- sul ting in published maps and charts. 3. Ruri.-of'f' records of' the Water Resources Division of' the U. S. Geological Survey. 4. Ra1n:f'all and weather data by the Department of' Com- merce, Weather Bureau •. 5. "Geological Investigation o£ Proposed Power Sites at Cooper, Grant, Ptarmigan and Crescent Lakes, Alaska" by George Pf'a.fker. (1954) 6. IIPreliminary" Area Power study" by Chugach Electric Association, Inc. (1954) 7. "Geology and M~eral Resources of' Kenai Peninsula, Alaskalt , Bulletin 847-I, U.S.G.S. (1933) 8~ -"Moose Pass-Hope District, Kenai Peninsula, Alaskall , Bulletin 847-I, U.S.G.S. (1933) 9. "Geologic Report on Cooper Lake Project" by William It. Judd, U. S., Bureau of' Reclamation. (1955) 10. "The Potential Wate'r Power of' Grant, Ptarmigan, Cooper and Crescent Lakes, Kenai Peninsula in Alaska near Seward" by Arthur Johnson, U.S.G.S.(1955) B. PRELIMINARY PLANS Several of the investigations and reports mentioned above dealt'with the power potentialities of Cooper-Lake" each involving the investigator's'preliminary" impressions o~ the project with a suggested plan of development. 1. The earliest report on powerf'rom Cooper Creek and Cooper Lake is found in U .S.G.S •. ivater Supply Paper' 372 'where G-l PORT1..AND • OREGON N 0 IT H PAC I FIe CON S U L TAN T S ANCHORAGE. ALASKA o u· o o u u u u u ~ ) w u u u u o u C. E. Ellsworth and R. W. Davenport stated that Cooper Creek drops 200 feet per mile and could develop 1000 HP for 5 or 6 months per year and perhaps 200 HP during the winter-time. 2. The first realistic report on the Cooper Lake pro- ject is found in the "Cook Inlet and Tributaries Interim Report N •. 02", by the Corps of Engineers, dated January 20, 1950. A JO foot drawdown on Cooper Lake was proposed to provide 57,000 acre-feet of storage to regulate the power draft to 96 cfs. A tunnel 10,350 feet long and 1570 feet of penstock. were proposed to transport the water to the powerhouse on Kenai Lake.. Prime power was estimated at 4,450 KW. 'An installation ot 8,900 1m at 50% load factor would produce 39,000,000 KWH annually at an esti- mated cost of $5,183,000 for the project or 7.8 mills per KWH. (1950 price index) ). In 1952, Mr. George Pfafker studied the geology o:f the Cooper Lake d.amSite and turmel and in IIAdvance U.S.G.S. Report, . July 1), 1954" concluded that. storage could be developed either by drawing the lake down 30 to 50 feet or raising the lake by a dam at the outlet 30 to 50 :feet high. 4. In March,. 1955, Wm. R.,. Judd of the. U.S.B.Ro made a. "Preliminary Report on the Geology o:f the Cooper Lake Uilit - Lawing Project". He stated the damsite at the outlet was suitable for a low dam.' His. intake structure indicates a lake drawdown of about 30 feet. The tunnel and penstock lead to a powerhouse on glacio-fluvial material on the shores of Kenai Lake. 5. The Arthur Johnson Report o:f the U.S.G.S., dated June, 1955, considers. the tunnel diversion plan as an lIalternatelt giving pre:ference to a plan involving a dam at the outlet to raise Cooper Lake 20 feet, creating 30,000 to 40,000 acre~feet of storage which would be sufficient :for complete regulationo:f the 5 years. o:f record, 1950-1954 even if Stetson Creek were diverted into Cooper Lake. From the dam, a pipe line 3.75 miles long. and a penstock 3500 feet long would convey the water to the powerhouse on Kenai River about a mile below the Kenai Lake outlet. Tailwater elevation would.be about 436 feet. The discharge would be 70 c:fs 90% of the time; 80 c:fs :for 50% of the time and the prime power would be 3500 KW and 4060 KW re- spectively. With Stetson Creek added, this would be 4570 KWand 5070 1m respectively. One o:f the major advantages-o£ this plan is the location of the powerhouse on the Sterling Highway. ' 6. The· IILawing Project" report o£ the U.S.B.R. dated Sept~ber, 1955 discusses the Cooper Lake and Crescent Lake projects in detail. For Cooper Lake, the 6 years o:f stream. :flow records are correlated with the-past l5-year rainf'all. record at Seward and the conclusion is reached that the average run-o:ff from Cooper Lake may be taken at 99.5 c:fs, as compared w.i..th the past 6-year-record o:f 88 c:fs. G-2 PORTLAND. ORe:OON NOR TH P A ( I F I ( ( 0 N S U L TAN T S ANCHORAOe:. ALASKA D lb o D u u u o lP u The tunnel scheme to Kenai Lake is proposed and 85,600 acre-feet of storage is provided in Cooper'Lake by tapping it some 60 feet below the. surface. An' annual firm output of 39,000,000 KWH is. indicated with a 9,000 KW plant' on a 50% plant factoro . The total cost is estimated at $6,861,000, and the average cost per KWH is given as 10 mills o C. PROJECT INVESTIGATIONS 1. Plans Studied.. A.thorough reconnaissance of the area in the Cooper Creek valley was made to determine a : suitable location for a power canal and/or conduit with a plant site on Kenai River. It was f'ound. that the east side of Cooper Creek would be particularly hazardous be-· cause of steep slopes with snow and rock slides common in several locations 0 This would require tunneling most of the way from Cooper Lake to a surge tank site above Kenai River. The west. side of Cooper Creek would require a much greater length of conduit and a lon- ger penstock. This location would cross Stetson Creek permitting a pick-up of' the f'low f'rom Stetson Creek ~thout the additional cost of a diversion canal back to Cooper Lake. These plans have been studied and the estimates prepared p;t"oved considerably more expensive than the plan of divert:1ng the flow to Kenai Lake from the southeastern end of Cooper'Lake. The cost of' a diversion dam and canal from Stetson Creek to the north~ end_of Cooper Lake was inc lude do 2.' Cooper Creek Dam. A study was made of developing storage by drawing Cooper Lake down and. having no dam at the outlet. To provide 80,000 acre- feet of storage by drawdown only, would require the outlet invert to be at elevation 11160 Such a project would be very dif£icult, hazardous,. and expensive and would lose valuable head.. It was there- fore~discarded. Next· a plan was considered with only 36,000 acre-feet of storage , with 18 f'eet of drawdown o Under. this plan the regulated flow from Cooper Lake. alone would be only 80 cfs and 56,500 acre- feet of water would be wasted during the 5-year period studiedo Plate "G-l" 0 This plan was not considered favorable and was dis- carded. The next plan studied added a low dam at the outlet to the previous plan, creating 63,000 acre-feet of storage --sufficient to regulate Cooper Lake discharge plus Ptarmigan Creek., This plan, Plate· IIG-2", had complete control of the run-off but still necessi- tated a rather' expensive cofferdam, or other method, in the lake to G-3 PORTLAND, OREGON NOR T H P A ( I F I ( ( 0 N S U LT ANT S ANCHORAGE, ALASKA u u u u u o r ~ w provide twmel outlet -plus the added expense of a 20 foot. dam at the lake outlet. The geology at the lake outlet is such. that a dam. 20 feet high would be nearly as expensive as a dam 10 to 15 feet higher as a large part of the cost is encountered in excavating for and con-· structing the spillway in the rock at the left abutment, and in the channel crossing. The final plan utilizes no drawdown· on the lake but de- velops all the storage by raising the lake 26 feet, creating 58,000 acre-feet of storage to regulate Cooper Lake alone (See Plate IE-3"), or raising the lake 34 feet (to elevation 1200) creating 80,000 acre- feet of storage -sufficient to regulate the ultimate project includ- ing all the additions such as Ptarmigan and Stetson Creeks6 This plan has an economical dam which enhances the power potential by raising the lake and increasing the total effective head. Two dam. sites were investigated at the outlet of Cooper Lake: one being immediately downstream from the outlet; the other approximately 1500 feet downstream. in a rock ca:nyon. The latter site would involve a 40 foot additional height o£ dam because o£ tlle fall in Cooper Creek. but is confined to a very narrow gorge which has considerable possibilities. The first site appeared most desii'able and most economical provided good foundations for a dam existed. Initial geologic investigations were. started at the upper site which indicated an 'exceptionally favorable fomation of bedrock on the left abutment providing an excellent spillway site, and, the right abutment was found. to be underlain with a compact. glacial till (hard pan) which is amply strong to carry all loads and is impervious. When these conditions were found,the detailed geologic investigation was concentrated in this areao Cost estimates of the two dam sites showed that an earth dam at the upper site was more economical than a dam at the lower'. site. Other types of dams were investigated and found to be more costly than the. earth dam. 3. Tunnel! Conduit and PenstoCk. The power tunnel, conduit. and penstock from: Cooper Lake to the power plant on Kenai Lake involved careful reconnaissance' and 'geologic study of-the' area· to locate the most suitable and economic location. The locations previously investigated by those making the earlier' reports on the project were studied and found to be entirely practical. The' area from Cooper Lake to a point well beyond the' . probable location of the lower portal consists of. argillite with in- terbedded graywacke lying in approximately vertical planes. This formation, is uniform within the limits of the area and its extent is such that any possible tunnel location would be in this material. The area above Kenai Lake was searched by ground and air reconnais- 0-4 PORTLAND, OREGON NO RT H P A ( IF I ( (0 N S U L TAN T S ANCHORAGE, ALASKA :w \ [], "0 o o u . DC I \ I U U I f 1 ,U I Ill) I 'U I , I U u u u u o o sance to determine where the surge tank and powerhouse might be 10- cated'to obtain adequate foundation materials and elevation to re- duce the distance' between the surge tank and powerhouse to a minimum., This investigation resulted in the location of a point of high ground south of Ptarmigan· Creek and considerably south of the areas'inves- tigatedby'otherso A very suitable powerhouse location on. bedrock outcropping at Kenai Lake immediately below the surge tank site was located. Prelimina.ry lines were run from this point to Cooper Lake to locate the tunnel and conduit lines. This data, when plotted, indicated a location Which appeared very satisfac~ory and detailed surveys were made for this location. This line is shown. on Plate 1 as nThe Alternate Tunnel and Conduit Linen. Detailed designs. and estimates of the layout, when compared with alternate lines which were considered, proved that a location following a direct line be- tween the intake point on Cooper Lake to the selected surge tank site was the most economica~ and was selected for the recommended. project. 4. Powerhouse. The site selected for the powerhouse is on an extensive exposure of solid gr~ackeo Geologic investigations proved the ex- posure to be massive and of suitable character for concrete aggre- gate. D. PTARMIGAN CREEK DIVERSION The tunnel and conduit line, originally selected and sur- veyed, referred to as "The Al ternate" on Plate 1 as well as the selected alignment of tunnel and conduit, cross Ptarmigan. Creek. The Ptarmigan Creek flow can be collected.: and brought into the con- duit at small expense and increase the capacity of the overall pro- ject. The cost of the additional installations required to include the flow from'Ptarmigan.Creek are approximately one-fourth the value of the added power produced therefrom. The addition of. this flow can be included at. the same time that the mainprojec~ is con- structed or added to the project at a later date to firm up the prime· power cap ac it,y. In'view of the recommsndedplan for-the reservoir'eleva- 1iion and the conduit location, .. the most economical method. of adding the flow from' Ptarmigan Creek will be by damming,the creek at a point a short distance above the condui~ crossing and pumping the flow from this dam into the conduit. G-5 PORTLAND. ORI:GON N a RT H PAC I F I ( ( a N 5 U LT ANT S ANCHORAGE. ALASKA D U u IU loa • II. INSTALLATION FEATURES A •. DAM The dam at Cooper Lake will be one of the key features of the project. It will provide sufficient storage to regulatecom~ pletely the flow from Oooper Lake and a:rry diverted flow added. The dam will add several. feet of "head" to the project thereby increas- ingthe power potential. 'The dam will be of the earth and rockfill type' With the impervious portion near the . upstream face. The type pf dam selected is based on safety and economy. Materials are immediately at hand for constructing such adam. The extensive rock foundation in the left abutment furnishes an excellent location for an uncontrolled spillway and. its excavation will supply ample rock for the rock por-' tion of the dam and riprap for the upstream. face. The 12 to 24 inches' of surface humus will be stripped off the entire dam base width and length and. the 1 to 20 feet of pervi- ous. glacial gravel and outwash underneath will be excavated from over the impervious compacted' glacial till on' which the impervious section of the dam will rest -furnishing a complete cut-off against underdam seepage.. The pervious' material excavated will be placed in the pervious section of the dam. (See Plate VIII.) Borrow areas are near at hand. for the impervious. upstream portion andthe.pervi- ous fill downstream from it. The downstream face will be largely rock from the spillway excavation and no extra riprap will be re- .quired. The impervious zone will be thoroughly compacted into place. The upstream slope will be protected by a layer of random gravel and spalls upon~ which will be placed the, 24 inches of rock riprap. The upstream slope will be 1 or 2!. The central one-third of the dam will be of compacted random gravel. fill with the finer graded. materials immediately supporting. the impervious zone ... The downstream one-third of the dam will be of more porous gravels and rock excavated from the spillway so as to provide a permeability at least 12 times that of the impervious zone 0 The downstream slope of the dam will be 1 on 2. The dam for a popl at elevation .. 1192 with crest elevation 1202 has. a length. of 500 feet o . With a pool at ele- vation 1200 and crest at 1210, the. dam'length would, be about 700 feet. The dam construction quantities are small, materials close at hand and it will be possible to construct the dam and spillway in one season. G-6 PORTI. ... NO.OREaON NORTH PACIFI( (ONSULTANTS ANCHOR ... aE. AI. ... SK ... U D u u u :~ : u.J I I U :U \ , ' 1 IW I U u ~o B. STREAM DIVERSION DURING CONSTRUCTION The six months from June to November constitute. the" work- ing season. at the ciamsite, although certain features. such as rock excavation in the spillway and riprapping the dam slopes could be car- ied on at other timeso During these six open months the run-off of the basin is at its height the peaks generally occUrring in June, July and September. Diversion of water must be accomplished to ex- cavate the cut-off portion across and under the river. Stream diver- sion is frequently a, vexations and costly problem. Sometimes both upstream and downstream. cofferdams are required with turmel, flume or channel diversions. A small dam like Cooper Lake Dam can scarcely afford such costly treatment nor is it required. There are two alternatives that appear attractive. First, it m~ be possible to divert 200 cfs through. the power tunnel into Ptarmigan Creek' during the month or six weeks required to excavate to impervious strata under the river section ot the dam and refill it to above lake level. Af"ter that is accomplished, it should be relatively easy to keep ·ahead of the rising lake levels even it di- version were discontinued. A second method would employ a cotterdamacross Cooper Creek just above the dam and high enough that storage on Cooper Lake would be ample to hold the inflow during' the time the river portion ot.the dam is excavated and rebuilt. This cofferdam': could' be incor~ porated into the final dam structure • Excessive pumping might be encoun'j;.ered by this method. . It will be' advantageous to discontinue diversion as early as-possible with a view to filling the reservoir by the time initia- tion of power' draft is desired -, about October of the following year. c. SPILLWAY 'Phe spillway: will be excavated in the solid .slate· rock in the left abutment. . The' spillwa;r will be 40 feet wide on the crest and its ungated. crest will be 10 feet below the top of the dam, allowing ample freeboard for'spill and for wave action under the most adverse conditions. The discharge channel from the spillway: crest back to the original. creek channel will be excavated from solid ro.ck and have a slope of 5% to provide easy get-away: for the spilled water. With a depth of 5.2 feet over the crest, the. spill discharge capacity would be 1250 cfs, sufficient -when combined with reservoir surcharge storage _. to control the udesign flood" of 5350 cfs.. See Plate VIII. No spillway training' walls will be required beyond the solid rock from which the spillway channel is to be excavated. If G-7 PORTLAND. ORE:GON N 0 RT H· P A ( I f I ( ( 0 H S U l T A H T S ANCHORAGE, ALASKA u u u U lb u u - need for repair should arise, it can be carried on 81J'3' year as the reservoir will seldom be full and actually spill is not anticipated. No sluices or sluice gates are to be provided in the dam or spillway. The power tunnel provides a drawdown outlet. D. RESERVOIR The reservoir will be created by raising Cooper Lake by means of the dam across the outlet, from its minimum elevation of 1,166 feet to 1,192 feet, providing 58,000 acre-feet" of. storage. The area of Cooper Lake is 2,150 acres (13% of the tributary"drain- age area) and the area of. the 1,192 pool will be .. 2,600 acres. At elevation 1,200 the pool area would be 2,750 acres, providing a useful storage of 82,000 acre-feet. Fifty percent. of the shoreline of the lake is steep and '. rocky' with no forest cover.. The balance of the shoreline has gent- ler slopes and benches near the lake. The reservoir (Cooper Lake) will have a storage capacity .greater than the average one-year run-off and is the key to the economy of this project.· Excessive run-off in years of. hea:vy rain- fall will be· conserved and rationed out during' years of sub-normal run-off, ;yielding' a controlled flow at all times' as' required to meet the stations power demand •. Very few hydro projects have this.great asset. ' . Another feature of the large reservoir is that itpraa- tically eliminates the possibility of floods reca.ching" spillway level., And if some combination of unforeseen events. should produce spillover the spillway, the great'surcharge storage capacity' on the reservoir will reduce the peak inflow to a relatively minor outflow. See Plate VIII. E. POWER mAKE The power intake will be located 4 1/2 miles up the east side of the lake from the dam; leading directly into the power tun- nel, pipe conduit and. steel penstock (total ,length 10,300 ft.), and connecting to the powerhouse situated on the shore of Kenai Lake some 733 feet lower. Storage at Cooper Lake is essential as shown by the Dis- charge Duration Curve, Plate "E-2" and estimated Load Demand Curve, Plate "G_ 3". It may be provided by drawdown of the lake or by stor- age on the lake by means of. a dam at the outlet. At Cooper Lake the damsite at the outlet is favorable. G-8 PORTLAND. OREGON NO RT H PAC I Fie CON S U L TAN T S ANCHORAGE. AI.ASKA J J . 1 .J J J J J w J "Head" on this project has a capitalized value of about $7,000 per foot. Raising the lake will provide. additional head, over· the drawdown p~an, by an amount equal to the raising of the lake plus some few feet additional, because the reservoir surface area increases at the higher elevations. For the ultimate project, the net head gained~ be as much. as 36 feet -equal to $250,000 in capitalized value to the project,. and almost equal to the total cost of the dam. In. the drawdown method, 40 to 50 feet depth of unwatering of the intake would be required, presenting a ver,r difficult oper- ation. in thiaremote area. Such a plan would mean an increase in tunnel excavation costs by reason of the need to hoist all muck from the upper end of the tunnel a distance of 50 to 60 feet. With the dam plan selected,. the . invert of the intake and tunnel will be at elevation 1,156 which is onlY 10 feet below lake surface. A cofferdam· around the intake end at such depth is a . minor problem compared to going down 50 feet. The lake E;lnd of the intake will be a flaring open cut to permit eas.r iriflow of water at low velocit,y. The reinforced concrete intake structure will be constructed on solid rock foundations at elevation 1,154 plus or minus, and rising 10 feet above the pool elevation. Reinforced concrete columns and steel trash racks will extend to the·bottom of the intake. (See Plate IX.) The cross sectional area of the trash racks will be sufficient to permit normal water passage at a ve- locit,y of less than one-half foot per second and at minimum pool, the velocity will be 1 1/2 feet per second •. From the intake tower, a 120 foo~ length of 7·foot diameter pipe w~ll extend back to the tunnel portal. The upstream end of this pipe at. the intake tower . will be controlled by a slide gate, provided with motor' and manual control. There will be an air· vent behind the gate, 'rising above pool level. F. TUNNEL AND CONIlTIT The tunnel portal will be· located at such point as the rock cover over the tunnel is sufficient and satisfactory and will be faced up with concrete; reinforced if necessar,r. The tunnel floor will. be held level for the first 2000 feet to facilitate haul- age of muck back. to the. intake end, thus providing two headings to speed up tunnel driving •. Cover over the tunnel. is relatively light, (100 to· 300 feet) and little II squeezingll ground is anticipated, nor much water although several fault zones and numerous contacts will. be encountered. The tunnel will be a nominal.Sfoot diameter horse- shoe, unlined. except in areas that require support which are' esti- mated to be less than 20% of its length. Through such portions, the cross-section will be a 7 foot horseshoe inside the concrete lining. G-9 PORTL."ND • OREGON N 0 RT H P A ( I f I ( ( 0 N S U L TAN IS ANCHOR"GE. AL.-'SK" u u u u u u I~ u u u u D U o ,0 ~ D , , The carrying capacity of such a tunnel is greater than required for this project, but an 8 foot size is considered the minimum working room for economy of tunneling operations. The extra ,size does save considerable "head" valued at $7,000 per foot and does provide large carrying capacity for over 50% of the distance from Cooper Lake to the powerhouse. The downstream end of the tunnel will be near 'Ptarmigan Creek and the crossing will be effected by steel pipe of 5 • .75 foot diameter which will. continue up the hill to the' surge tank. At Ptarmigan Creek, there will be a "trap" and blow-off to intercept gravel, 'rock and other debris that may find its way to that point, thus preventing its passage to the water. wheels." This t1trap" and blow-off may be used during dam construction, to draw Cooper:Lake down and to keep it down during the six weeks required for unwater-, ing the foundations of the main storage dam across Cooper Lake out- let. Such discharge would flow down Ptamigan Creek to Kenai Lake. The 2075 feet of 5.75 foot· diameter steel pipe from the main tmmel to the surge tank wi]:l be of 3/8" steel plate, buried and covered to prevent freezing. G. SURGE TANK The surge tank:w1ll be situated on'the highest point avail- able -about elevation 1150 -and will be a 15 foot diameter steel tank above groUnd, ristng to elevation 1220. The base willpe at elevation 1120 (more or-less) over-the 7 foot diameter lined tunnel under' the surge-tanko (See Plate IX.) The surge tank above ground, will be su:rrounded by a heavy wood covering with a 4" air space for circulation of heat'supplied by electric space heaters during cold weather. The top of the tank will be covered but provided with a spillway and air vent. H. PENSTOCK The welded steel penstock will be 2,450 feet long' and varying in diameter and thickness according to economic design from 5 feet 9' inch diameter x 3/81t' plate at the top to 4 feet 9 inches x 7/811 plate thickness at the powerhouse wye. The penstock will rest on concrete saddles every 20 feet and large concrete anchor blocks will be provided at all major changes in grade. The penstock will be buried in rock trench and, fully covered. In the interestof'economy, there will be a single pen- stock for the ,two units -even if one unit is del~ed, which does not appear'probable. Each branch of the wye at the powerhouse will lead to a turbine through a 36 inch pipe line controlled by a 30" gate valve de'Signed for 750 foot head. 0-10 PORTLAND. OREGON NOR T H PAC I Fie CON S U L TAN T S ANCHORAGE. ALASKA ~ o u o u u u u ; ) w f ) U u u u ~O I. SCROLL CASE AND DRAFT TUBE The scroll case will. be flange-connected to the penstock branch line at the control valve and. conform to the turbine manu- facturer's design dimensions •. Through it" the water will be deliv- ered to the turbine blades and passed. on down through. the steel draft tube _. also of the manufacturer's design. The penstock, wye, turbine and draft tube will be securely-anchored to the solid rock and concrete of the powerhouse foundation. J.> TAlLRACE 'The tailrace will consist of a short length of concrete lined,. rock-excavated cha:rmel discharging directly into Kenai Lake. . Normal fluctuation of Kenai Lake will control the tailwater eleva- tion ranging from elevation 433 to 438 in average years with a pos- sible maximum level of 442 feet above sea level in years of excess- ive run-off. The lake elevation controlled the turbine setting. III. POWER AVAlLABLE A., BASIC POWER . The a:rmual load and daily peaks fluctuate from month to month with maximums in December and January (Plate 1I(l-.4n). :Tlle It azmual load factor" of a~ power sy-stem is the average annual power' demand in KW divided by the peak KW demand.. In this-syStem study, a load factor of 50% was found to be representative of the· service area and therefore the installed capacity was: computed on that basis .. It has been found that for' Cooper Lake alone, the long term average discharge available for power production will be 90 cubic feet per second 1£ completely conserved and regulated. On a 50% load factor this would.mean·that the maximum draft would be 180 cfs. With the large storag~ available, tbere will be complete.control of discharge or power draft and the' power demand can be met at any and every' hour throughout the years,. IIp to that limit, or' even. higher demands if needed to meet a critical peak to the peak installed ca-' pacity of the units -if larger'capacity be chosen. Over a period of years the average net head. at the Cooper Lake. Project will. be about 734 feet. With 90 cfs average. flow this would develop 4,750 KW continuous or 9440 KW on a 50% load factor basis allowing' for increased friction losses (See Plate IIG-5 11 ) and -an . installation of 10,000 KW peak capacity Would be warranted. G-ll PORTLAND. ORI!.GON N 0 RJ H PAC Inc CON S U L TAN T S ANCHORAGE:, ALASKA o o u u f ) U u r ; U u u u o B. PEAKING CAPACITY Consideration was given to the installation of 2 -, 6000 KW units with a plant factor of 39%0 No more KWH. could be produced but the 2,000 KW of added peaking capacity could be very useful on oc- casions and would prove economically justified if the rate schedule is based on a "service" and lIenergyll charge with about $1.00 per month. per KW of demand. There are few possibilities of providing system peaking capacitY" as cheaply as at the Cooper Lake project. The features which contribute to ,economy of capacity at this project are: 1.. Complete control' of water supply. 2. Very inexpensive storage. 3. Oversize conduit for over 50% of the distance. 4. Short overall length of conduit in relation to the total head. 5. Short penstock. 6. RelativelY' high head pennitting use of high speed units and theref9re smaller parts. 7. Good foundations throughout. For these reasons consideration, should be given to some surplus ItcapacitT' at the Cooper Lake Project. With the monthly demands fluctuating as shown on Plate oG-4", the average demand is 83% of the, peak monthly average. A daily load factor of about 60% results in· an annual load factor of 50%., If peaking capacity were installed beyond the 50% plant :factor, it would be very useful to supply both energy and capacity at any'desiredrate (up to the plari.tts,peak capacity) at. any time during the year, but especially during'the winter when many other plants will be deficient in water. To operate in this manner would necessitate curtailing Cooper Lake Project.s energy output to an equal extent, during the summer time. The, ultimate project including Stetson Creek and Ptarmigan Creek diversions would provide 115 cts continuous flow for-power and with an average 'net head of. 734 feet would develop 6,100 KW contin-' nous or 12,100 KW on a 50% load factor. On the same basis that 12,000 KW of installed, capacity is desirable for'the Cooper Lake alone situation, an installation of 15,000 KW is recommended for the ultimate project. The. plant factor under such. conditions would be 40% • . G-12 PORTL.AND • ORKGON NOR T H PAC I Fie CON S U L TAN T S ANCHORAGE. ALASKA u u ( : W u r \ f 1/ L.a' .' 5'=:':- U ( \ ! ~ u u r' U o U 0':) ( 1 ~ C. HEADS The f.unctions of the reservoir are described. under par. II-D and II-E above. A complete cycle of reservoir operation is shown on. Plate "E-3". This plate shows that, under' normal power operations, the reservoir does not completely fill except at the end of a year of exceptionally heavy run-off. By means of this "routingll study, it is proved that the system power demand can be produced each month to meet the estimated. loads based upon the assumed load demand curve. From this study, one is provided w.ith the average reservoir level, average tailwater'level, average gross head, 'aver- age net head and power available at arr:r time. (See Plate "G-6".) The "net" head effective for power is found by deducting all hydraulic losses through the tunnel, conduit and penstock from the gross head, (which is the difference between reservoir level and tail-water level). These losses fluctuate w.ith the changing rate of flow due to power demand. Economic formulae are employed to determine the proper diameter of conduits and penstocks by as- suminga value· for power lost through loss of head. in the various sections of' conduit and penstock and equating these varnes against increased cost o£ conduit or penstock required to reduce such losses. The rate of flowtbrough the conduits will vary throughout the year (higher in winter, months) and. throughout the day (higher in theeve,ning) • See Plate "G-4" ,Monthly Load Demand and Plate 11G-5 1t Daily Load., Curve. With a 50% load factor, the friction losses'are'estimated to be twice as great as those due tp passing the same anlount of water at a tIlliform rate (or 100% of load factor). With various load (or'plant) factors the friction losses varymarked.ly -and each case must be considered separately -as the resulting friction losses affect the size o~ conduit or penstock to be used. The gross, head between Cooper Lake at elevation 1168 and Kenai Lake at elevation' 435 is 733 feet. The, maximum storage level for Cooper: Lake alone will be 1192 and the gross head 757 feet, and the'average reservoir elevations wil~ fluctuate over the years be- tween 1166 and 1192 with a mean of' about 1181.5 and an average gross head of 745.5 feet. Average friction losses at 50% plant factor operation will be about 11.1 feet, leaving a net head of 734.4 feet. For the: 111 timate project with: storage pool elevation of 1200 and mi.nimtim drawdown at 1166, the maximum gross head., would be 765 feet, the average gross head 755 feet plus or minus and. the average net head 734.3 feet., G-13 PORTL.AHD • ORItGOH Non H PAC I Fie C D N S U L TA N T S ANCHORAGIt, AL.ASKA o is { 1 ~ U u r ' I ~ ( 1 , I I 'I.J I U U lb U I 'u !U I U U D u D. FLOW' AND POWER DURATION The Flow-Duration curve on Plate "G-7t1 shows that the natural flow of Cooper Creek varies greatly and that, for 60% of the time, the discharge is below average and, that for 10%· of the time, the discharge is above the capacity of the proposed plant and therefore without storage that surplus must be wasted. The horizontal, line at 90 cfs indicates that, with com- plete control a uniform discharge of 90 cfs may be maintained_ at all times from Cooper Lake alone. To meet the system's fluctuating de- mands, it will be necessary to adjust this. average discharge over a wide range each day and throughout the yearo Sufficient storage will be available in Cooper Lake Reservoir to meet these requirements without loss of water -(except for some abnormal and unforeseen oc- currence). The horizontal line at 115 cfs indicates similar' condi- tions for that discharge for the ultimate project -including Stet- son Creek and Ptarmigan Creek. The. Power Duration Curve on Plate tf G-7" shows that 40% o:f the time the uncontrolled discharge could produce 100% plant AVERAGE capacity or prime power and during 10% of the time some water would be· wasted (unless stored) because the inf'low is greater than required for the full capacity of the plant. During 50%· of the time the plant could operate efficiently on the load curve, meet all the peaks, pro- duce all. the KWHs needed, and produce some secondary KWHs, but would waste some water. Above 50% of-the time, the plant would be greatly defi- cient in energy but could still meet peak demands by using-pondage from the Lake for a few hours each day_ Without large storage this power energy deficiency would automatically continue throughout the winter months -the season of maximum demand. See Plate tlG-311 _ With the storage reco:mm.ended for this project the designed capacity and energy demand can be met at any and all times -as shown by the hori- zontal line at 4750 KW for~ prime power available-from Cooper Lake alone and 9440 KW power available on a 50% load factor demand curve. A peaking capacity of 12,000 ~w may be economically installed at this plant. For the ultimate proje~t .including Stetson Creek. the ca- pability would be 6,100 KW prime power (continuous), 12,100 KW on a 50% load factor and 15,000 KW peaking capacity at about 40% load factor. G-14 PORTLAND. OREGON· NOR T H P A ( I F I ( ( 0 N S U L TAN T S ANCHORAGE. ALASKA I ~ -lb o u u u u U J r~ I J.U" U U U IU i ! u o o r.P D ~ ~ ~ C\ ..... C't I.c'\ Q\ ...... iq 0\ ..... ~ ...... ~ • COOPER LAKE PROJECT Sfudy or inifiB/ phase wifh no dam. Run-OTT Of Cooper Lake plus Pfarm'Yan Ck. Drawdown £l//66 fo//49=3~000 Acre Feel: Q =/06% of Cooper Lake gage. Mean flow: 96.5cfs. Q Oblained= 80 CF.s.' K~o= 8~;707=4030K~D Wafer Losf=.56;520A.E CI) Em ~' ~ I I j 1"-"') 1""-; I ...... ..., 1 -~ Il'"'\ .~ ~ Ir:::.: I ~. l~ ~ . "'\ m .~ v , 2 ~ ;-" (;) ", CI) r"', .... ~ m-') ") -1""- ~ ~ I ~ ~ "-In: I :; "'\ I ...... I ~ .'4 I~ \ M \r .... " c:) f CI) If ,I ..l ~ otl t ') ",I ..., I~ .,. W I ...... "'"', bill" 1'\ .1 1m ~ 1"<: . 1 '. I .. . .., "" ."" . J 1 '" t\\ ~ 1 t1\ ,.... ~ .... Ct--. .~ "-" 1 I' 1 Ie--It"'I ") r"1 I' ~ ..... ~ Itt-. I 1'- !§§!g It"; I V ,-~ /' '" () "" l 1\J'} c., ......... ""-I"'" I t" ;I ~ il, a, -...;, \ I\, V ") ...... I '1 "'\ .. ""{ ~ ~ IC'\ ~ ~ In\. -' ~ .... .' .1 1 ~ ") ~ m <:) \ ~ ,..." ~ , c.., 'I:( 1I ........ , ") ......... ') '" r-.. ~. mE I J ~ IC\J I .-'" c:r.. / "-~ I ..... f ./ Cl r--... i' f=m ~ c:) , C) ~ <::) <::) ~ ~ t:::: NO / .L tT <::!!., .11 :1" 7 :? '!:. ~ " ......... ....... ..... J..-..--. North Pacific' Consulfants PlafeNaG-/ o lb. o r '\ U U U ( , I ~ ( ) w u . r \ U U U U o o I'D"'" (),- w U COOPER LAKE PROJECT Sfucfy of' Inifial phase wlfh low d.am. Run-off oT Cooper Lc;ke plus Plarmtgan Ck. Drawdown £1//77 10 /146 = 64 000 A c re-Feet Complefe regula/ion obla/ned "Q/'used =106% Cooper Lake 6age. Mean f/ow=9G.5cfs .. KJ1foa= 9G.O x 714 = 4880/< Woo Wafer Los! -none. /4 ~~4-~~~4-~4-~~~~+4~+4~~-r~~ ~~4-~~~4-~4-~~+4~~~+4~~-r~~ ~~4-~~H+4-~~~~~~~~+4~~-r~~ ~~4-~~~4-~4-~4-~~~~+4~~-r~~ ~~~~r+~H+~r+~~~~-r~~+4-r~-r~~ ~~~~~~~+;-r~-r~~~~ ~~~~~~ '~~~~~~~-r+4-r~~~ ~~~~~~+N-r~-r~-r~ ~~~~~H+~~~r+~r+-r+7~~~~- ") ~~~~~~~~~~~~-r~-r+~~~~~~~~~~~~-r~~+~~~r+~M+~~~~~r+~~~~ ~~~~~~~~~~~r+~~-'~~~~~M+~~~~~~~~~")~~~~H+~~~~~~~±7-~~~4-~~H+~~~~4-~~~~~~~-r~~ ~~4-~~~~~~~4-~~~~+4~~~~~ ~~4-~~H+~~~~~~~~~~~~-r~~ Norfh Pacific Consulfanfs Plate #0.6-2 o : J_ \) o u u u ( I ~ U :u lD U r ) W iU I \ i ' W ( 1 U o U r I ...J ~ COOPEf2 LAk"E' PQOJECT COMOAR.ISON OF NATURAL l2uN-oFF WITH C3TIMATED LOAD DEMANO l4~~~--+-~~h4~~--+-~~--~~ ~J1 ~~~--+-~~~~~~+-~~--~~ < ~. J 0 1----1---+--+--f+__~74fi~r_r:,.~~'r7'I--~~ It... ·0 ~ 8 I--~~~~~......r-__I~~~~~~~~~ __ O~'-A..£..£...£.J.':....c..L~~.LL.J.~~~"""'-"''''''''''''-'~''''-''-II'''''''''''''''''''''''''''''~ Jon. Frzh. M8r. Apr. Mc!J June July Aug SfZpf. {}cf. Nov. INc. MONTJ-I.:J Norfll Pacific Consul/ants P/ateNo.G~3 D U (5/ o U U U :U I I U ~u L3. U U 'U u u u o GO U ~ ~ a "-J '.J ~ ~ ~. <: ~ ~ ~ ::z:: ~. ~ COOPER LAKE PQOJECT ANNUAL LOAO' CURVES IQ5 Jar). Frzo. MtJr. Apr. May ~um July Aug. Sept Ocl: Noll. IQO 9.5 go 8.5 8:0 7., 7.0 ~ 'r-Cu v-Jl~ of' ~oa -::Is t Or /' \' ..... ~n( hOI ~CJg~ A~ ~a-.......... ~ I\.. ...... " ~ur DlI l !.Sf, ~R. !/ I--" '-,,-/1 ~e ~ '" P\f /0 v-£ "<-Iu .J-na 11 /. ~/ \::: V v ~ "~ ~ ~/ 6~5 6.0 5.5 ff.O 4.5 4.0 4VE eAG E. /1 i40A THL Y Lc l4D~C .1 NI DEk CE" IT C ~FA NNl VAL rOTA L 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 Dec. j"'~ /I Annual L.oad Curve in % used lOr CA.P.A. Service' Area. . 9.5" 9.0 8.5 8.'0 7.5 7.0 ].0 8.0 8.0 8.5 9.0 lao Norfh Pac/ric COrJ,5VI/Cinf.5 Plale NaG-4 D '1 '" o ( 1 ~ U r \ U IU \ U u u U D rO IJ f ) U ISO /.II) IJ() I 20 '/0 /. 100 .st1 150 70 GO SO 40 .JO 20 /0 0 r-- I-- -COOPER LAKE PQOJECT TYPICAL DAILY LOAD CURVES MAXIMUM DEMAND IN /oooK.w. C/Iy or Anchorage --.----Chugach Elecl: Assoclnc~ ( 1-. Y c r A r,( ~f °r~ ~ ~;; "I ~ ~y e. Ie ~I nc ~n d 7";Ji ~ £ IIfJJ ~Iy L Oc ~d ;: ~( ~t( )r 7-~)' -.... ' I-----,....--..... ' ...... ,..-. ......,; 1.- ~ -~-.. """"""" --.. ~ P--... ---,..... , .... ~ r-- ' ~- l"""-e t--h tic: tJ.a ~) t> .4 ',;:-~ ec t ~.! !os pc: .J. n( . A ~ f!. ~c ~.n ~d \n< 1;.; ;-e. ~l. 0 ~J ~ ~1 L Dd iiI, "..J It J. 0 ~d f ~( ~fl r VI t" - r-- 12345G789~Ha~u~~om~~ann~ /iOURS AFTER MIONITE -MARCH ~ 195, /Vorlh Pacific Consulf8nls Plafe#aG-5 o l6 u u u u ( ) w u u u u J' o U GO Q=cfs L'i/!.~J. , 7' ',ur 6'iS'fZ"a~ Friction COOPEQ LAKE Pf20JE:CT' ..)UMMARY OF OPERATING CONOlnONS UNDER THREE ASSUMED LOAD FAcT02S INITIAL PROJECT ULTIMATE"PI20JE:CT 90 180 230 //5 230 288 10070 50Z 3910 IOOZ 50! .40l. 745.5 745.1 745.J' 749.~· 749.5 7495 64' 11./ , , 202 8.1' /5.2 , 26.6 I NrzfffMcI . 7J 9.1' 734.4' 72.5." 74a8' 734~3' 722.9' KW 4750 9440 1/920 6/00 12/00 /4900 ~ _ c.(" . .t?:~ f .' 19.2 . .CLf?:!I1: I...?~ PO ~rf!.I~t:?'?!-' --------~ !brei -;z-- Ay.~POQ fllel] .... '!bra -;;--1/855 ,8 rtPO~.-Ft -I -;I-;;~'-;.~lXX?~.Ft .. ------: .. /6000 I n I n.. 1I~~ __ .... "'r_ ............. _,.'. T _. _ _.. _ _ • ______ ---.... J ............ t-------_. " ~,.. ......... ''''J ~ I-"+~h,~'" , r""""'" 14000 .... "...' (..",.. ~'" o~ ~~..- tu j9j )~,. rrJ2 'OOKW··, 12000 ;.. ~ lI'tICe. 1.1 J[wr : d ct.9.r~ ..,.,.... .,..- I ...J ~ kO~' ~ ~ 10000 ""t ~r o~ ~ )KW~:;; --~ ...... 944t:. .. ~. ~ <0 ~ ~. dOOO 1\1 .~ l&.I. \J ~ 90 cr: ) .~ ~ //5Cf '5 ~ ~ ~ ~. (5 J,.,..t'" .~ 6 'ooKW 6000 t , -.....£J ~'=-2~ v-':::..--~ IOC ---. .. co 4'750~ k"W 6 ~ 4000 II~ ,: f..: '-J ,ll.{ .r-. Ct) 2000 .I I ,. , L .-, 1_ ..L K..t:./\ 'AI LAic .1:. .,Ave: • Iell I YYc/ ~r I.../(CV. .lfJO --. . ---- 0 Norflt Pacific Consulfanfs Pla/eNo.G-G o Ua u u U I U r \ J u u r 1 . ll) U U r ) I • ~ COOPEfZ LAKE PQOJECT' DI.:5CI-IA2GE AND POWE I<. , TIME -DURATION CURVES 7()OIr----r---,----~ \-,.----r--~____r-__r_-_r__-7000 \ o~~--~~-~-~~-~~-~~ o 20 40 60 80 100 XOF TIMe Norfh Pacific Consul/anh PlakNo.G-7 w o cs u i r I W u , r ) \W u u 'U I , r ) l.J iU I I r \ :U j U U o o ~O o APPENDIX liB" HYDROELECTRIC POWER PORTLAND. OREGON NO RT H P A ( J F I ( ( 0 N S II L TAN 15 ANCHORAGE. ALASKA o 0:-1) U U iU \ u u u u o U !LP I IU CONTENTS Hydroeleotrio Power PART. I. Water Power Available A. Power Market, Requirements and Capabilities - - B •. Physioal Limitations - - - - - - - - - --.-- Co Eo onemo s .. -.. .. .. , -.. .. .. .. .. -. .. .. ... --. .. .. ... Do Alternative Developments - - - - - - ---- - E'o Transmission. -. --. --. --. - --. -. -. -. -. --. - F. Cooper Lake Alternate Plans - - - - -... - -... - 1. Cooper Creek-Kenai River Plan - - - - - - - 2. Tunnel Plan to Kenai Lake - - - - - - -... - 3. Cooper Creek Power - - - - - - - - - - - - 4. Ptarmigan Creek - - - - - - - - - - -.;. - - 5. Stetson Creek - - - - - - - - - - - - - - -. G. Initial Installation - - --'.-- - - -.... - - 1. General ...................... _ ....... -....... _., .. 20 Installed Capacity - - - - - - - - - - - - 3'0 Plan 1IA-111 ............................... -............. ... 40 Plan "A-2 ft , -........ ' ... -' .............. ~.-, ....... _ ... 5.. Plan "A-3" -' ...... , ... -" ................... -, -', -, ... -,. 6. Plan "A-4ft -,_ ...... -'-' _. -, -, -' ...... -' ...... ... 7.. Ptarmigan Creek -:. - -•. - --. - - - - --- H. Ultimate Installation. --, - --. --. - - -_. -.. - I. Stetson. Creek Diversion - - - -• - - - -_. 2. Ptarmigan Creek Diversion - - - -_ .• ' _. _ - 3. Ultimate Plans - --. - - - -.• '. -• -.'-• I. Generation Capacity ~ ;.. --- - -• -. -__ . -_ 1. COop'er Lake Only - - - - - - - --.-__ _ 20 The Ftt11 Projeot -. - - - - - - -_ -~ -. _ 3. Average Annual Generation - - - - - - - - - PART II. Power Installation H-1 H-17 .H-18 H-18 H-19 H-19 H-19 H-20 H-20 H-20 . H~2l H-22 H-22 H-22 H-23 H-23 H-23 H-24 H-24 rH-24 H-24 H-24 H-25 H-25 H;'25 H-26 H-26 Ao ~bines·"'''·'' -................. -, ................ -. ..... H-26 B. Governors _._,-' ...... ~. -,-~-............... _--~-.-,...... H-28 C. Shut-off Valves - ---- - - - - -•. --. -.--H~28 Do Generators --- ---,_. - - - - -_.-- ---H~29 Eo Eleotrioal Equipmen~ - - - - - - ----• - -H-29 10 Main Step-up Auto-'I.':i-ansformer -' -_.'-- - -H-29 20 Generator Switohgear -. - - - --'.-- - - -H-30 3. Station Servioe Power-- -•.••• -.-'--H-30 4. Lighting System --. -~ .. -. - --. _. - -•. -... H-31 50 Powerhouse Grounding •. --. - -•.•• '. •• H· 31 60 Plant Control -• -..... ...; .••. -. -. -. -, -H-3l 7,. Duplex Switohboard • ---• -••. -. - - - -H-32 8. Station Battery, Charger,·and Control Cubiole H-32 9. Eleotric Service to Intake, Surge· Tank, Operators r Residences -• - - - --. - - - -H-33 10. Meohanioal Equipment --- - - - - - --.. H-33 PORTLAND. OR&QON NOR T H P A ( I F I ( ( 0 N S U l TAN T S ANCtiORAQE. ALASKA o D t5 U u u u u , ) u u u I u o I I. WATER POWER AVA:n.ABLE A. POWER MARKET, REQUIREMENTS AND CAPABn..ITIES The power market area considered in this report is wide- spread, covering the Palmer-Anchorage-Seward and Homer'areas. This area is an economic nnit and, within a short time will be f.ully served.bya transmission grid. system of which the lines from Cooper Lake project will be a part. Such a system permits complete inte- gration of the various generating projects and consuming markets, thus adding to the system1s potential capabilit,y through both hy- draulic' and electrical. inte gration. . With the growth evidenced throughout this market area, the spreading of distribution lines by R.E.A. Cooperative Associations throughout the area, and the probabilit,r of increased commercial and industrial loads, the addition to the g,ystem of a generating nnit such as Cooper Lake with its low costs will act 'as a furtner stimu- lant to power consumption. The projects contribution of some 50 million KWH annually will be. absorbed so quickl,y that the next plant for development must be selected at once, to keep pace. with local growth. (See Plates "H-2" and.II H-3"). ' The following tables are a summar.y of the·areats past and future requirements and capabilities.. Explanatory discussions fol- low the tables. H-l PORTLAND. ORECON NOR T H PAC I F I ( ( 0 N S U L T A NT S ANCHORAGIt. ALASKA " 0 ~ ,. ,. z a . 0 !II .. Q 0 z :z: c lila -1 == -a ;p. ,.... ...... ,.... ,.... c :z: VOl c:: .- -1 ;p. :z: -1 VOl ,. z n x 0 !II ,. a PI ,. ~ .. " ,. c-._, L,J t:II I I\) System 19~1 MEA-Alaska 2 1,200 REA-Alaska 5 80 CEA-Alaska B 3,)00 KLEA-Alaska 17 Subtotal .... CAPA 4,580 New Defense Load Total-CAPA 4,580 Anchorage-City 9,000 Seward -City 790 Subtotal -Cities 9~790 Total -Area 14,370 ------.---' ~-"'-" r=::= \J> TABLE ::1 Area Fi:rm Power Requirements Past and Future Annual Peak Demaridin Kilowatts 19~2 19~3 19~4 19;; 19~7 1,800 1,908 2,160 2,629 3,200 172 200 . 240 449 1,100 4,700 6,892 9,290 11,000 14,100 50 540 6,672 . 9,000 11,690 14,128 18,940 . 6,672 9,000 +1,690 14,128 3,000 21,940 9,980 12,140 ' 12,040 13,244 15,500 . '920 1,060 1,170 1,350 1,800 10,900 13,20013,210 14,594 17,300 17,572 22,200 24,900 28,722 39,240 19~9 . 3,700 1,650 17,040 720 23,110 3,100 26,210 18,400 2,400 20,800 47,010 ---"~--------- 1901 1903 . 4,200 4,700 1,810 2,016 19,410 21,700 900 1,013 26,320 29,429 3,200 3,300 29,520 32,729 ' 25,500 21,700 3,200 4,-200 24,900 29,700 54,420 62,429 L:J £..:=J ~. V, 190; 5,550 ,2;300 23,500 1,200 32,550 3;400 35,950 '29,500 5,600 35,100 71,050 '0 0 ~ ,. ,. z D . 0 21 PI Q 0 z z: «:) :1112 -4 ::I: -;a.- '"' '"" ~ IF UI ~ «:) z: ...... c: r- -4 ;a.- z: -4 ...... ,. z n ::t 0 :II ,. " !" ,. ~ (10 :II ,. TABLE II Area Power Generat:lng Capacity (Nameplate) Present ~d Proposed' Plant 1951 19~2 Annual CaEacitz in Kilowatts . 1953 1~54 1955 1957 19~9. 1901 ·1903 MEA None --REA-Biesel 250 250 690 690 855 1,400 1,400 1,400 1,400 CEA-Diesel 3,500 4,100 3,550 3,450 3,250 950 950 950 950 Nov-Dec II -steam 9,500 9,500 9,500 9,500 14,500 14,500 14,500 14,500 KLEA-Diesel. ~-... ---100 275 Cooper Lake-Hydro --~ 12,000* 12,000 12,000 Ne~ Defense Loads --~ -~ Standby only BuRec -Eklutna ----32,000 32,000 32,000 32,000 32,000 Anchorage-Diesel .-5;636 6,636 7,836 7,8)6 . 6,736 6,736 6,736 6,736 6,736 II -Hydro 2,000 2,000 2;000 -2,000 --- II -steam .3,500 '3,500 3,500 3,500 Sewarq -Diesel 8)0 1,630 1,630 . 2~8)O 2,830 2,830 2,8)0 2,830 2,830 li . -.Hydro 3,500 3,500 7,000 7,000 ---. Total .-CAPA 3,750 13,850 13,740 13,640 27,705' 31,125 42,850 42,850 42,850 Firm -CAPA 2,'875 10,725 10,390 10~290 20,215 24,125 35,850 35,850 35,850 Total -Cities 11,966 13,766 '14,966 16,166 25,566 29,066 29,066 32,566 32,566 Firm -Cities . 8,136 9,566 9,-566 10,366 16,366 17,566 17,566 21,066 21,066 Total !"': Area 15,716 27,616 28,706 29,806 55,271 62,191 73,916 17,416 77,416 Finn -Area 11.761 23.291 22 2956 23 2656 36.581 45 2 191 56.916 60.416 60.416 ,Gained by Integra- tion 750 3,000 3,000 3,000 3,500 3,500 3,500 3,500 *This power would be increased to 15,000 KW if the Stetson Greek diversion were added. -==r'\.~ VI 1965 1,400 950 14,500 12,000 32,000 6,736 2,8)0 ,,7,000 . 42,850 35,850 32,566 21,066 77,416 60,416 3,500 • o " :: o z )0 z o :c o ~ a .!" )0 E III I/" System MEA -Alaska 2 REA -Alaska 5 CEA -Alaska 8 KLEA· ... Alaska 17 Subtotal-CAPA New Defense Load Total -CAPA Anchorage-City Seward -.City Subtotal"'Gitie~ Total -Area TABLE III Area Energy Requirements (Inoluding 10% fo'r Transmission Losses) . Past and Future Thousands of K. W .H. Annually 1953 • 1954 1955 1957 1951 3,853 6,702 277 598 11,47519,075 ---16,605 26,375 16,605 26,375 8,795 750 34,733 44,27 8 44,278 9,424 '850 42,580 --- 52,,854 '52 854 . , . 39,500 ··43,414 58,650 55,500 3,559 4,152 4,762, 5,600 43,059 47,566 63,412 pl,OOO 11,660 1,200 47,080 100 60,240 60,240 57,000 6,600 63,600 14,800 5,600 61,700 2,150 84,250 14,300 98,550 70,500 '9,200 79,700 17,250 6,500 74,200 2,949 100,899 14,700 115,599 1961 . 19,700 7,400 84,740 3,550 115,390 15,100 130,490 22,600 8,302 94,330 4,272 129S04 15,500 145,004 1965 25,500 9,100 101,900 4,900 141,400 15,900 157,300 8.3,800 98,500 116,000 134,000 12,900 18,000 25,?00 36,000 96,700 116,500 141,200 }70,OOO 59,664 73,941 107,690 113,954 123,640 178,250 212,299 246,990 286,204 327,300 TABLE IV Area Firm Energy Production Capability Present and Proposed • "0 .l9~1 19~2" Thousands ot K. W.H. Annualll- 19~9 1901 1903 ' 1965 0 Plant 19~3'19~4 19~~ 19~7 ~ z 0 ,MEA 0 HEA -])iesel 548 548 1,489 1,489 1,818 ------21 PI CEA -Diesel 12,045 14,673 iii --... 0 z No"V"Dec ,0 -steam ---3,500 44',019 43,581 38,505 46,037 56,392 41,022 41,022 41,022 :z: KLEA-Diesel 219 c lOa Cooper Lake-Hydro 41,000*-41,000 41,000 41,000 -t :: New Defense Loads ------Standby Only -.:II BuRac -Eklutna -----110,000 136,600 136,600 136,600 136,600 136,600 :II>-,.... Anchorage -Diesel 3,446 3,264 3,264 3,264 2,544 "'" ::Q II -Hydro 15,000 20,000 20,000 20,000 ,.... I " -steam 15,000 15,000 15,000 15,000 \.n. ,.... Seward -Diesel 2,190 3,635 3,635 7,139 7,139 Q :z: With CAPA-Hydro 15,300 15,300 46,000 46,000 46,000 ..,. c:: wlo CAPA-Hydro --12,395 12,395 27,725 27,725 27,72$ r-CAPA Total -Diesel 12,593 15,221 1,489 , 1,489 .2,037 -t :II>-CAPA Total -steam 3,500 44,019 43,581 38,505 . 42,068 52,423 . 54,423 52,423 52,423 :z: -t CAPA Total -Rydro 48,000 63,600 104,600 104,600 104,600 104,600 ..,. CAP~ Total -All 12.593 18,721 45,508 45,070 88,542 105,668 157,023 157,023 157,023 157,02) )0 Cities Total-Diesel 5,636 6,899 6,899 10,403 9,683 -----z n '! II -Steam 15,000 20,000 20,000 20,000 ---x 0 " " -Hydro 15,000 15,000 15,000 15;000 62,000 76,939 76,939 92,269 ., 92,269 92,269 ~ " " " -All 35,636 41,899 41,899 ,45,.403 71,683 76,939 7p,939 92,269 92,269 92,269 !' )0 Area Total-Diesel 11,513. 30,260 5,124 , 8,628 9,683 ~ co If " -steam. 25,000 28,500 80,423 ;79~985 40,542 46,037 56,392, 41,022 41,022 41,022 ;)C ~ " " -Hydro 15,000 15,000 15,000 15,000 110,000 151,900 192,900 223,600 223,600 223,600 II " -All 51 2 513 73 2760 100 2 547 103 2613 i60 2 225 197 2 937 249!292 264 z622 264 2622 264 2622 Gained by' Integration 3,284 13,140 13,140 13,140 15,330 15,330 15,330 15,330 15,330 *This energy 'WOuld be increased to 53,000,000 KWH if t.he Stetson Creek diversion were added. -: 2 z o o :II III 10) o z ,.... ,.... Q :z: ...." c:: ..... -t ".. :z: -t ...." Plant BuP..ec-Eklutna Little Eklutn~ City of Anchorage Nelf Diesel TABLE V Area Generating Facilities iri utility Plants November 1955 UNIT-KW. P.F. H-15,ooo-o.90 H-10oo-o.80 H-looO-o.80 D-1136-o.80 D-10OO-o.80 D-llOO-o.80 D-llOO-o.80 D-llOO-o.80 Descrlption 600 rpm Francis runner by Newport News Oerlikon Generators 0~9 P.F., 16,667 kva -Installed 1955. This plant is tied to Anchorage by a single 115 kv circuit and 30,000 kva substation' at Anchorage (3-single phase units, no spare). Another single i15 kv circuit feeds Palmer through a single 5000 kva 31 substation transformer. A future al ternate supply route is being worked out for Palmer. 720 rpm Francis by Pelton & G.E. Installed -1929 "" " "" II " -1935 These units were purchased from the City of Anchor- ag~ and are tied through a 2500 kva bank to the Old 33 kv line to Anchorage which is not'now readily available for use.,. There is a plan now unclerway to provide for a tie of this plant to the, 115 ~ ~stem. ' 720 rpm Fairbanks-Morse, Elec. Mchry installed, '49 II "General Mo tor Ellio t "t 50 " , "" II II Elec. Mcbry II H,l II II " "Ideal II 1,52 "II "!III II t 52 All the above were rebuilt engines When installed. This plant is connected through a 3750 kva trans .. f'prmer 'bank to the 33 kv system in the City of Anchorage. Plant now used for peaking only. This plant is considered capable of supplying about 3300 KW flrm at about 50% annual load factor •. Plant.Cap'Y Total-30 , 000 KW. Energy figured on 30,000 @ 52% LoF. a l36~6 MVffi annually Firm power .. 15,000 KW Total-2000 KW Energy .. ° Probab ly use for dump power only, or· emer- gency sUpply Total-5436 KW Energy figured on 3300 @ 50% L.F. "" Plus 2136 @ 5% L.F. "" Flrm Power .. 3300 KW o :II III Q o Z :z: CI -.... ::c t"'\ CI :z: "" c::: r-.... :.... :z: .... "" Plant Old Diesel CEA -Knik Arm (Anchorage) TABLE v -Cont. Area Generating Facilities in Utility Plants Unit-KW. P.F. D-700-o.80 n-60o-o.80 n-55O-o.80 n-400-o.80 S-3000-0.80 S-3000-o.80 S-3000-0.80 . s-500-o.50 . November 1955 Description 225 rpm Washington-G.E. Installed -1937 327 rpm Worthington-G.E. " . -1947 The W~shington unit was pew when installed, the Worthington was War Surplus. A 1200 kva trans- former bank ties these units to the 33 kvsystem of the City of Anchorage General Notel The two plants above are isolated from one another by about ~ mile line disuance and about l-! mile by road. They require separate -operating crews. The old plant is strictly a. last resort. 327 rpm Cooper-Bessemer-Elec. Mach. Inst'ld-1951 "" " " " " II 1951 -Tnese dies~l unit~ are War Surplus units which were converted from gas to di~sel operation. The oper- ating record since tneir installation in Knik Arm Plant haa not been good. The operators prefer to use them in emergencies only although they have been used for occaSional peaking . . 3600. rpm Worthington-Elec. Mchry, Installed-1952 " "" "II " 1952 II " " "" " 1952 " "Westinghouse-West "1952 The large units were new wbe~ installed. The small steam unit }lTas a War Surplus item which has given excellent service. Plant Caply Plant III 1300 KW. Energy figured on 1300 @ 5% L.F .... Firm power - 600 KW. Total a 10,450 KW. Firm Power lOr 7,450 KW o :II .. g o z ,..,. o . .z:: "'" c: r- -t ,.. :z: -t "'" -----------------------'_., Plant Inlet (Anchorage) HEA -Homer Soldotna KLEA-Moose Pass TABLE V .;. Cont. 'Area Generating Facilities in utility Plants November 1955 Unit-KW. P.F. Description D-750-o.80 J};.750-o.80 D-60o-o.80 D-IOO-o~80 D-IOO-o~80 D-125-o.80 D-125-0.80 D:'300-o.80 D-75-o.80 D-85-o~80 D-50-0.80 D-50-o.80 720 rpm General Motors -Installed-1951 u" II.. U 1951 II" II II II 1949 . 1200 rpm Superior II 1948 II II " II 1948 The three G.M. Units were rebuilt engines when installed. 'The two Superiors were used equ~pment - original use unknown. The plant is in operating condition, but its location (which requires a separate 'operating crew and tank truck oil de- livery) ,argues in favor of' disposing of, .the units. It is estimated that disposal will be complete by the end of 1956. 600 rpm Enterpris~-Elliott -Installed-1951 "" II II II 1951 450 rpm II II, II 1953 These diesel units f~ed the HEA distribution system through a 1000 kva bank connecting both the 7.2/12,.5 ley and 14.4/25 kv lines to the plant. These diesels we~ new units when installed. They have been supplying all power for HEA system. 1200 rpm Caterpillar Set-War Surplus, Age unknown. II 11:11 II -Pure hased from CEA 1955 ~ese units are temporarily installed at Soldotna. 1200 rpm Caterpillar Set-New when installed 1952 II II I! II _II II II 1953 Plant Caply Total ... 2300 W. Firm Power ... 1550 K. W. Total'" 550 KW. Firm Power ... 250 KW. Total ... 140 KW. Firm Power ... 75 KW. Total ... 100 W. Firm" 50 Kw. "U 0 ~ ~ z 0 . 0 21 III Q 0 Z :z: Q :I11III -4 == ." > 1"'\ "'" ~ 1"'\ I '0 1"'\ Q :z: v-. = ,..... -4 > :z: -4 v-. ,. Z n :t 0 21 ~ a l' ,. r ,. UI :01 ,. ----------~-----,------------------------------------- Plant City ot Seward , Diesel Town ot Kenai (Private Power System) TABLE V -Cont. Area Qenerating Facil~ties in Utility Plants November 1955 ' Unit-KW. PoF. D-100-o.Bo D-lOO-o.Bo D-100-0.80 D-200-0.80 D-330-0.80 D-800-0.80 D-1200~0. 80 D-40-o.Bo 'D-50-0.80 D-50-o.Bo D-200-o.Bo , Description 600 rpm Worthington - ~ II " ' II '! !' 1200 rpm GeJleral Motors 514 " Fairbanks-Morse 327 II Cooper-Bessemer 327 II Cooper-Bessemer (?) rpm International -Age unknown 1200 rpm Caterpillar -II 1/ 1200 rpm II -"" Installed 1941 " 1941 ., 1941 " 1947 ' " 1950 " 1952 II 1954 327 'rpm Fairbanks-Morse -War Surplus purchased by CKA and ~tored 5 years then sold to Private Systel1l Owner. The .unit will probably be' in service in 1956. ' The small units listed above are in poor condition and service has been ot such a nature that several local consumers have purchased and are operat;tng their own plants. ' Plant Caply Total :z 2830 KW. Firm Power "" 1630 KW • Total:z 140 KW. Firm • 90 KW ? TOTALS: Installed -55,246 Firm 29,990 u ~ u u u u r 1 U u I U ~ IU f , i • J u r i W U o WO o Notes to Tables (1) MEA -Alaska 2 Service Area.. The service area of the MatanuskaElectric Association in- cludes the Matanuska Valley, Knik River Valley south to the Eagle River where the area joins the northern lWt of the CEA system, ,the Little Susitna'River valle,y' paralleling the ,Talkeetna MOuntains north- erly to Willow and sweeping' around 'Big Lake on the south to the vi- cinity of Goose Bay on the Knik Arm of Cook Inlet. Load Estimates. Estimates for power requirements of this area were taken from the "Power' Requirements Studyll, prepared by the REA· in.1953 ~ the "Ul timate System Stuc:W Engineering ReportUcompleted in: September of 1954, and a,recent adjustment of load estimates which was prepared by REA and approved by the Matanuska Electric Associatjpn Board of Directors, November 28, 1955. Considerable new load is developing from defense inStallation near the MEA system;-These are considered separately. Generating Facilities. , The MEA has no generating facilities and in the past has ,purchased its poweJ" supply from the Anchorage Public Utilities Sys- tem, then from the Chugach Electric Association via the transmission lines of the Bureau of Reclamation Eklutna project" and now from the Bureau of Reclamation Eklutna project under terms of a contract for 5000 KW of firm power. ' The MEA is a charter member of the· Central Alaska Power Association, Inc. (2) HEA -Alaska 5 Service Area. The service area of the Homer Electric Association includes the Kenai Peninsula region bounded, on the south by Kachemak Bay, on the east by the Kenai Mountain Range, on the ,west, by Cook Inlet, and its northern boundary extends northerly from Skilak Lake to Turnagain Arm aDS Westerly along the Arm to Cook Inlet again. The REA pre- sently has facilities extending from Homer to Soldotna. H-10 PORTLAND. OREGON N 0 RT H PAC I FIe CON S U L TA N T S ANCHORAGE, Ai.ASKA. D u u u ( 1 W U ill) I . ( 1 iU !u u u o o o [J o Load Estimates o Estimates for future loads were taken. from the. REA "Power Requirements StudT' prepared in 1953 and include the requirements for the Town of Kenai which is presently served by a small. privately operated system. Considerable new load is developing by virtue of new defense installation near t~HEA power s,ystem. These loads are considered separately. Generating Facilities~ The Homer Electric Association generated its own electric power in a diesel plant located at Homer, and in a temporary plant located at Soldotnae The Soldotna facilities are not now connected to the power lines feeding from Homer but it is estimated that this connection will be made in 1956. The diesel units in the Homer Plant are in'good condition and certainly could be used in the future for peaking purpose as well as emergencies. The units in. use at Soldotna should be held for emergencies only. For the Town of Kenai, see Table V. The REA is a oharter member-of the Central Alaska Power Association, ~co (3) CEA -Alaska 8 Service Area. The service area of the Chugach Electric Association. joins with that of the MEA on the north, borders the City of Anchorage on the east and south, is itself bounded by the Chugach Mountains on the east,. extends along' the north side of Turnagain Arm to Portage and v:lcinity and in this region joins. with the proposed service area of the Kenai·Lake Electric Association. Load Estimates. Power and energy requirements are developed.' from the REA Power Requirements Study of 1953,. the Ultimate System Engineering Report completed in Februar,r 1955, and include additional loads for the Fairview Are'a (formerly served by the Inlet Light & Power Co., which was purchased by CEA in December, 1954) and the Alaska Rail- road and Alaska Native Service Hospital which receive, both heat and electric energy from the Knik ~Power Plant of the CEA. Generating Facilities. The CEA has in the past purchased power from the Inlet Light and PoWer Co., the Anchorage Public Utilities and the City of Anchorage. It supplied generating equipment to the Inlet Light &. H-Il PORTLAND. ORItGON N 0 RT H P A CI F I ( (0 N S U L TA N T S ANCHOR"'GIt, ALASKA D 0, \) U u o u r 1 W ILD i U -f 1 'U I" !U u u u o 10 l..l o Power Co. to supply its first system and by 1951 had the diesel section of the Knik Arm Plant in operation. The complete-steam plant was finished as a joint effort of CEA-ARR in 1952. The CEA has in addition a power contract with the Bureau of" Reolamation. Eklutna project is for 9000 KW and they are presently constructing a 5000 row addition to the Knik Arm Power Plant. This addition will . be complete at'the end of 1956. The diesel units in the Knik Arm Plant are converted gas units and the operators prefer not to use them except in emergencies, because of a poor operating record. The diesel units at the Inlet Power &l;ight Co.· Plant are being disposed of gradually. ' The CEA is a charter member of the Central Alaska Power Association, Inc. (4) KLEA -Alaska 17 Service Area. The Kenai Lake Electric Association is the youngest oper- ating cooperative of the group. -Its proposed service area extends from the City of Seward north along the Seward Highway to join with the southeasterlyboundar,y of the CEA. The area extends westerly from the junction of the.SterlingHighw~ and Seward Highway to a 'point, along the Kenai River where at Skilak Lake it joins lP-th the northeastern bounWLr;y line of the REA. The Cooper Lake Hydro Project ,is about'in the center of the KLEA proposed service area. .';I'lP.s ser- vice area has been challenged by the City of Seward which proposes to serve portions of it in connection with their proposed Crescent Lake Project. ' Load Estimates. The load estimates given herein are c\etermined on the . basis that the KLEA will-serve its proposed system. The estimates ',for' the City of Seward have been for the City only'. The sum of the two should be about equal regardless of the division o:f this sec- tion. The loads for the KLEA have been taken :from the liRE! Power Requirements Stud;yll of .1953. Generating Faoilities.' The· KLEA is now generating its own power supply and is operating the Moose Pass electric system under a least-purchase agreement using local financing., A new. loan application is being prepared for :funds'to extend. the system. The diesel units in'the KLEA plant at Moose Pass and probable future units there are o:f such nature that they should ultimately be used for emergeneies only. The KLEA is a charter' member o:f the Central Alaska Power Association, Inco H-12, PORTL.AND • OR£COON NOR T H PAC J F J ( ( 0 N S U L TAN T S ANCHORACOr:. ALASKA D lis o u u u , ) u u u u u u u o /~ itJ 1.J o (5) New Defense Load Load Estimates. These new defense loads are known to be under construction or about· to· become so. Negotiations have already' taken place be- tween military officials and cooperativeassaciation personnel to arrive at final agreements on details. The size and energy require- ments for these loads have been supplied by the Militar,r in con- nection with the negotiations mentioned above. Location. These loads are predominantly located on the Kenai.Penin- sula, but some are in the Matanuska Valley areao All those known will be connected to the rural system lines. Generation Facilities. These loads will have some standby generation for emergen- cies only. Such generation is not listed since it is for temporary use only and would not be synchronized and operated w:lth an integrated system. (6) Anchorage -City Service Area. The service area of the City of Anchorage extends from Knik Arm of Cook Inlet on. the northwest boundary in an easterly direction along the Elmendorf Air-Force Base to the point where it joins the limits of the GEA service area near Mountain View and follows this meeting around the City to the south and then west again along Chester Creek to the Knik Arm (except for Fairview within this area served by CEA) It There may be some interchange of area. between the City and the CEA as time passes but iri this report, the service areas are reported as presently delineatedo Load Estimates. The future load estimates were developed from data supplied by the City of Anchorage. Generating Facilities. The generation facilities of the City of Anchorage in 1951 included the Little Eklutna hydro plant. with. two 1000 KW units in- stalled, and one 1100 KW diesel unit installed at Little Eklutna; one 1000 KW, one 1100 KW and one 1136 KW diesel unit in a plant at Anchorage; one 600 KW and one 700 KW diesel unit in another plant H-13 PORTLANO • ORItc:lON NOR T H P A ( I F I ( (0 N S U l TAN T S ANCHORAc:lIt.ALASKA u u ( ) ~ u !U U La> U u u u D o located at Anchorage; and a 5400 KW steam turbo generator unit (down- rated to about 3500 KW because of cooling problems) in the stern end of the "Sackett.Harbor" (a tanker) which was beached at Anchorage for the purpose of supplying power. In,1952 and 1953 two more 1100 KW units were added to the larger diesel plant i:D;::Altoborage. However., the substation limits the· output. In 1955,·' atterthe Bureau of Reolamation began operation of the Eklutna hydro-projeot, the Little Eklutna plant was trans- ferred to ownership of the Bureau of Reolamation and a 16,000 KW power contract with the Bureau went into effect. At this same time the diesel unit from Little Eklutna was brought to Anohorage to re- plaoe another unit which was burned in ,a fire" the nSackett Harbor" was sold and towed away. The City of Anchorage has been invited to join. the Central Alaska Power Association, Ino. (7) Seward -City Servioe Area. The service area of the Cit.y of Seward at present is mostly within the city limits except for a few lines to· the north of the city. The City is now extending lines to a point about 8 miles north of its limits through an area originally part of the proposed KLEA electric system. Further expansion to include more of. the territory proposed for and partly' now being' served by the KLEA. has been pro- jected by the City. This would include all areas along the .Seward Highw~ to the junction with the SterlingHighw~ and along the Sterling Highway to Mile 57 (approximately at Hinton I s Lodge). Load Estimates. The load estimates as here presented for the City of Seward are as set forth in the Ci tyl s "Crescent Lake Project Report". It does not appear that these estimates include any load growth outside the normal. expanding city limitso The load estimate for the KLEA have been listed for its proposed system intact; it is believed that there is essentially no overlap in the estimates and that therefore the sum of the two represents the available load. regardless of who serves it. Generation Facilities. In 1951 the City of Seward had generating facilities con- sisting or five diesel units aggregating 830 KW. In 1952 another 800 KW'·'diesel unit was added bringing the total to 1630 KW. In 1954 another 1200 KW diesel unit was added bringing the total. installed capacity to 2830 KW which is the present plant capacity. As referred to above, a preliminary permit for the investigation of Crescent Lake as a possible hydro site has been issued by FPC to the City of Seward H-14 PORTLAND. OREGOH N 0 RT H PAC I F I ( ( 0 N S U l TAN T S ANCHORAGE. ALASKA o Lts U : 'I ~ IU I iU I I U U iU I ill> , : \ , I \W , U , ( 1 :L.J I U u o o fO U and additional engineering work has been accomplished this year. Accorddng to the original engineering report, it is proposed to in";' stall 3500 KW initially and that this might be accomplished by 1956. It is believed, however, that the present planning would indicate a' date not earlier than 1957. The 1954 report further states, that an additional 3500 KW unit would be added by approximately 1960. The City of Seward has been invited to join the Central Alaska Power Association, Inc 0 (8) U. S. Bureau of Reclamation Service Area .. The Bureau of Reclamation Eklutna hydro-project is located about mid'!"way between Anchorage and Palmer on the Palmer Highway. A 115 kv transmission line extends from the plant to Palmer where a 5000 kva substation feeds the MEA electric system.. Another 115 kva line extends toward Anchorage where a 30,000 kva substation feeds the City of Anchorage and the CEA electrical systems. There is alsO proposed an emergency tie between th:1.s Anchorage substation and the Military facilities at Ft. Richardson. and Elmendorf Air-Force Base. Generation Facilities. The project installed. capacity· is 30,000 KW. Power con- tracts with MEA for 5000 KW, CEA' for 9000 KW and the City.of_.Anchorage for 16,000 KW obligates the full capacity of .. the plant. Firm energy is rated at 136,656,000 KWH annually. The 2000 KW installed at Little Eklutna is .expected to be used for emergencies only. The Bureau of Reclamation has a project investigation under way at Caribou Creek near the foot of the Matanuska Glacier about 120 miles from Anchorage. Completion of the preliminary report on-this project was estimated by Commissioner Dexheimer to be· 1958. Portions of the Bureau f s "Lawing Report" concerning Cooper Lake were released in'. 1955:-by the Bureau to the Central Alaska Pciwer Association. for their use in connection with their inVestigation of the project. The Alaska Reconnaissance Report on the Potential Development. of Water Resources prepared by' the Bureau of Reclamation includes some very brief descriptions and estimates of potential power sites which could be developed .. (9) General Notes (a) The Corps of Engineers, Alaska District, has contributed greatly toward the progress of hydroelectric power development in this area of Alaska.. The investigations carried on by the Corps staff in their search for data for the "308" report has given. them excellent H-15 PORTLAND. OREGON N 0 RT H PAC J Fie CON S U L TAN T S ANCHORAGE. ALASKA u u u u U ILO U U u o background knowledge for providing useful data. The advice of some of these men. in Alaska resulted in the' selection of the Cooper Lake area by the Central Alaska Power Association for its first full scale investigation of hydroelectric projects. This choice appears to have been excellent. Another project in this area which has been the sub- ject of a special report by" the .. Alaska Distriot is the Bradley Lake Project. (b) Total Generation. Total. generation includes all units capable of operating on a steady as well as peaking only basis. Stand- by or emergency generation is not. listed since it is for temporary use only and in :ma.ny cases is arranged for specific type duty only. Totals forCAPA include 14,000 KW from Eklutna which is under contract to CEA (9000) and MEA. (5000). (c) Firm Generation includes only the generating oapacity which could be guaranteed continuously on a basis of supplying loads with monthly load factors between 60 and 75% and annual load factors of about 50%., This firm figure then reflects the loss of, use of the largest single generating unit in each groUp of interconnected units. The Bureau of Reclamation Eklutna plant has the largest single unit in the area. This unit (15,000 KW) represents almost 30% 0:£ the total generation of the system,. excluding the militar,r generation in 1955 and 20% of the estimated total in 1965. Nameplate ratings of units are used in all caloulations. The overload capacity of units is hot considered since the load es- timates are considered conservative and therefore of. similu. .. order as nameplate ratings. Good system operation requires some "spinning reserve u to handle situations where loss of a unit temporarily over- loads the system. On a.B,1stem as developed here it should be noted, that the loss of the largest unit (15,000 KW) camot .. be replaced by- overload capacity of alL remaining' units' -·even in. 1965. (Overload figured at 10% for diesel units, 20% for bydro units,. 30% for steam. units.) . (d) .. ,;Energy Capability_ The energy producing capability of generating capacity is calculated on the basis of 50% L.P. on the firm power rating of inter- connected units .. ' The 50% load factor' represents the average estimated annual load factor' of the. system load~, Generation by various plants will show hydro energy utilized first. Such hydro energy-is based on the plant rating if now operating, or, the estimated rat:ing (for plants not yet ouilt) based on the proposed installedcapaoity, the reservoir' regulation characteristics and the assumed run-off., For purposes of demonstrating the advantages of complete integration, the data tabulated .. in Tables II and IV is totaled in. the following ways: H-16 PORTL.AND , OREGON N a RT H P A ( I f I (. (0 NS U l TAN T S ANCHORAGE, ALASKA u o u u u U lD u u u f ) LJ D o cP o (1) Total and firm' figures for CAPA reflect no inter- connection between CAPA members for 1951 to 1955. Bureau. of Reclam- ationEklutna was added in 1955 and in 1957 the CAPA figures assume interconnection between all CAPA members only and the Bureau of Reclamation. (2) Total and firm figures for Cities reflect no in- tegration between them or with any other system UP. to 1955. In 1955 there is a cormection and contract with Bureau of Reclamation only by the City of Anchorage. From 1955 to 1965 no further intercon- nection made between Cities' or other systems. (3) Area total and firm figures reflect the actual effective interconnections through 1955 and assume these continue through 1956 and that in 1957 the transmission system proposed by CAPA is completed and the CAPA and Cities participate in one inte- grated operation •. . The Area Gain by integration is shown as the difference between the arithmetical sum. of tAPA and. Cities figures and the Area total figures. The Area Gain by integration in 1955 as calculated above shows as zero. This happens because the Bureau of Reclamation begins supply:ing the City of Anchorage and CEA and serVed to nfirm up" both agencieso The arithmetic therefore does not show. any gain •. Actually the addition of the Bureau of Reclamation plant to the system gave 30,000 KW to the total,. 15,000 KW to firm supply and allowed the Anchorage area to consider an additional 3,000 KW as firm·power. At the same time, the· Sackett's Harbor was sold, the'~sel removed from Little Eklutnaand some units were removed from the Inlet Plant of CEA. The actual gain in firm power between 1954 and 1955 as a result of all the above was about 13,000 KW. From 1957 through 1965 the gain through integration is represented by the difference with and without the Seward Electric System. B~ PHYSICAL LIMITATIONS The. immediate market is the controlling factor in the se- lection of a proposed generating' station •. The piecemeal. development of the past in the Palmer-Anchorage-Kenai Peninsula area has been dictated by the immediate need of speoific loads, the lack of know- ledge of . future expansion, and lack of overall planning and managemento This' is true of both the civil and military power programs in this area. Hydro-electrio projects rarely lend themselves to piecemeal development because of. their size and remoteness, with the result ' that most local power needs' have been met by thermal installations at the load centers: of the area. This type of generation is expensive, both in installation cost and operating cost, but has served as a means to an end. Eklutna is the first sizable hydro-electric installation H-17 PORTLAND. OREGON N 0 RT H P A ( IFf( ( 0 N S U L TAN T S ANCHORAGE. ALA$KA u u u u u ( 1 W u u u u o 10 ~ in the area and definitely points the way for further projects of this type. Eklutna was a favorable site in that it had most of the elements required for econo~, viz: storage capacit.y, high head, . and proximity to the market, resulting' in short transmission lines .. Its overall size was such that it could readi17 be absorbed by the market area. at an early date and thereby retire many ver,y uneconomic thermal installations. It is still too early in this market area to attempt con- struction of plants with capacities of several hundred thousand kilowatts --unless the load is definitely guaranteed by a major con- smning industry. The financial burden of carrying charges while waiting for load growth is the deterrent that dictates development of smaller hydro projects in the early stages of a system's growth. In the not-too-distant future, this trend will be reversed and only major projects will command interesto C. ECONOMICS Pby'sical limitations and economics are inseparable as shown in the previous paragraph. The high cost of thermal plants in the market area is well lmown o Installation costs range up to $450 per KW with accompanying fixed carrying and operating charges of $35 to $40 per KW/yr. to which must be added fuel cost of from 9 to 15 mills per KWH •.. -. Such costs must still be borne in isolated locations where only small loads are available. The time has arrived, however, when a transmission grid throughout· the area·will bring uniformly lower rates to each communit.y, resulting in"increased demand which will further reduce costs. This is the well-known spiral -in reverse .. A transmission grid is needed for the future, and the future is here - now. The Cooper Lake Project' and its transmission'lines are the first long steps forward toward an adequate area power' system. Others will follow quickly. D. ALTERNATIVEmVELOPMENTS There are a nwnber of hydro-electric power sites within economic transmission distance of Anchorage and its tributary area. Most of them are too large for' the present local market and must await the advent of major' industrial. loads. The Susitna projects and Lake George are examples. While the complete development of such projects would result in low-cost power, a partial. development to meet local requirements at this time would not. Caribou' Creek, a tributary of the Matanuska, is under: study and may prove, favorable as its capacity is not too large. Most of theseprojectsreqaire high dams to provide storage for stream regulation and head for power. H-18 PORTLANC • OREGON NOR T H PAC I F I ( CON S U L TAN T S ANCHORAGE. ALASKA u u I ) w u u , 1 U : ru' , I I On the Kenai Peninsula there are a number of small lakes at various elevationS which provide the possibility of head for power and storage for stream regulation. Some of the more promising ones are Grant, Ptarmigan, Cooper and Crescent Lakes flowing into Kenai Lake. Of these, Cooper Lake, the subject of this report, is the best, although Grant Lake is very promising but too small for an initial project. Bradley Lake near Homer appears to have outstanding possi-~ bilities in regard to head, storage and ~eld and may be good for 25,000 KW, although accurate data is lackingo The large Peninsula lakes such as Kenai, Skilak and Tustu- mena could also supply large storage and although the head available at each is relatively low, the prime power output could be quite high due to the large size of the drainage bas:ins. At present, their de- velopment could ~ause more dislocation of the local econOmy and might interfere more seriously with salmon culture than the small lakes in . the headwaters. For these reasons, the smaller lakes are more at- tractive at this time, and Cooper Lake is a ver.r desirable first de- velopment. E. TRANSMISSION Distances between scattered cities and communities of the area are relatively great. Thus, the expense of transmission is an item of considerable importance, especially with an initial small development. However, as, the' system grows. during the 50-year life of a project, the loads will increase greatly and what .was once,.an isolated plant will become the center of an extensive transmission system. F. COOPER LAKE ALTERNATE PLANS The basic project consists of means to utilize the outflow from Cooper Lake through a drop of 734 feet to Kenai Lake or to Kenai River. This is most readily accomplished by a short ti:umel, pipe line and penstocks from near the upper east side of Cooper Lake to Kenai, Lake. 1., Cooper Creek -Kenai Hi ver Plan. An alternate route following. directly downstream along Cooper Creek from the storage dam at Cooper Lake could serve a power- house on the Sterling Highway about one mile down Kenai River from Kenai Lake.;, Such a project would have the advantage of being' located directly on' the highway, sav:ing a few miles of transmission line. However, the disadvantage and added costs are such as to far' outweigh these· advantages. Of first importance is total cost,. This route would require 3-3/4 miles of pipe l:ine" all of which must be buried -- much of it along steep, rocky mountain slopes. The pipe line and H-19 PORTLANO • ORECiON N 0 RT H P A ( J F I ( ( 0 N S U L TAN T S ANCHORAClIt. ALASKA u u u u r ) w u ~ .. u u u u u u o rJ' service roadway would be difticult to construct and. maintain --with real danger that snow slides might take out the pipe line and would close and possibly take out the road each winter. The penstock would be 3,500 feet long and the overall friction losses in pipe line and condnit would be high and costly in lost power. This layout would be unsatistactor,r and uneconomical .tor a low load 'facto.r· plant.. It is probable that satisfactor.y foundations tor powerhouse and anchorage tor penstock would be dirt.icult to find. With oVer twice the overall length trom. intake to powerhouse it is estimated that the cost'ot' the Kenai River location would be at least $1,000,000 more than the tunnel plan to Kenai Lake. 2. Tunnel Plan to Kenai Lake. . The tavored plan consists ot a 5,650. toot long, 8-toot horseshoe tunnel, 2,075 teet more or less ot 5.75 toot diameter pipe and 2,450 teet ot penstock --total 10,300 feet --to a powerhouse on Kenai Lake. The principal teatures which make this plan attractive are: (a) The large capacity tunnel can carr.y large quanti- tieso£ water with relatively ~ittle loss o£ valuable head. (b) The short conduit and penstock distance in. re- lation to the ettective head provides a plant suitable. for large capacity installation at low cost. (c) A. splendid powerhouse site on solid rocktounda- tion is available. (d) No part ot the project will be in danger ot snow . slides. (e) Comparative estimates ot all alternate plans tor development' of the project covering both the Cooper Creek-Kenai River Plan and the Diversion Plan to Kenai Lake' show the latter plan to have the lower overall cost .. 3.· Cooper Creek Power .. The average run-ott ot Cooper Lake is about 91 ats, and with an average net head ot 7.34 teet, would yield 4,750 KW continuously at 84% efticiency and. warrant an installation of 9,440 KW at 50% load tactor •. This output is. based on ample storage tor complete regulation overa'period of years. 4., Ptarmigan Creek. The Cooper Lake Project pipe line between the outlet . tunnel and the surge tank crosses Ptarmigan Creek. A small dam some 3,500 teet upstream and a suitable pipe line copnection to the conduit H-20 PORTLAND. OREGON NOR TH P A ( I F I ( (0 N S U L TAN T S ANCHORAGE. ALASKA u u u u would add the available flow at the creek when Cooper Lake level is below approximate elevation 1175 or about 40% of the time, coinciding with periods when storage is low. A dam some 1700 feet upstream from the conduit crossing will intercept more flow than the higher site, and with a booster pump will put all the flow into the conduit except the extreme peaks for which pump capacity would be uneconomical. The average run-off of the Ptarmigan Creek area of 5 cfs (6% of Cooper Lake area) thus added to the project will add 265 KW continuous, or 530 KW at 50% load factor with a capitalized value of over $200,000. The cost is estimated at about one-fourth of that sum. Therefore, it is considered desirable to include this step in the basic project, although it need not be constructed until some later date. 5. Stetson Creek. Stetson Creek lies northwest from, and adjacent to., the Cooper Lake Basin and joins Cooper Creek about a mile downstream from Cooper Lake. Its waters can readily be diverted into Cooper Lake with storage provided there for its regulation. The yield of Stetson Creek is estimated to be about 30% of the Cooper Lake run- off or 27.3 cfs. A small diversion dam and open canal 1.5 miles long can accomplish the diversion. During severe winter freezes, Stetson Creek run-off is very low --only 2 or 3 cfs --and it is assumed that during 3 months the canal will be inoperative. A canal capacity of 70 cfs will carry all of Stetson Creek waters except for a few days during peak floods. Adjusting for these losses and seep- age at dams, leaves the yields of the various stages of development as follows: Cooper Lake alone • • • • • • • • • • • • • • •• 90 cfs Cooper Lake plus Ptarmigan Creek • • • • • • 95 cfs Cooper Lake plus Ptarmigan Creek plus Stetson • • 115 cfs The power added by Stetson Creek would be 734 x 20 = 1050 KW or 14 2100 IDi at 50% load factor with a capitalized value of at least $1,000,000. This feature could be delayed to later years if so de- sired, provided powerhouse units, penstock, and pipe line are in- stalled initially for the ultimate project. Decision should be reached on the final total project therefore, before construction of the initial project because the size of pipe line, penstocks, size of units and amount of storage to be provided are all affected by the final layout. It will be im- practical to change such items as pipes, penstock, generating units, etc., after they are once installed although the necessary regula- tory storage could be augmented at a later date by raising the storage dam 8 feet. H-2l PORTLANC • OREGON NOR T H P A ( I F I ( ( 0 N S U L TAN T S ANCHORAGE. ALASKA u/ u u u u u· u 'U ,U I I W lU o u G. DIITIAL INSTALLATION . 1. General. . Plate No. 1IG-6 n is a su:mma.ry of the water power available from the project under three load factor conditions for the Cooper Lake run-off only and for the total project which includes Stetson and Ptarmigan Creek flows. The initial installation should be se- lected with a definite plan for the ultimate development, which will require that a decision be made on the Stetson Creek diversion. There are four plans which warrant consideration. 2. Installed Capacity. The prime capacity of Cooper Lake alone is 4, 750 KW and on a system load factor of 50% an installation of 9,500 KW would be necessary. As previously enumerated, there are so many factors con- tributing toward installation economy at this plant, it is felt that at least 12,000 KW" are warranted. For the ultimate project including Ptarmigan and Stetson Creeks resulting in a prime capacity of 6,100 KW and a system load peak of 12,200 KW, it appears that an installation of at least 15,000 KW is warranted. With stability of service in mind from this isolated plant, it is most desirable in a system of this size to install two units ·in the interest of continuity of service and flexibility of use" One unit may be closed down temporarily for repairs or overhaul without materially affecting the plant t s KWH output. COOPER LAKE PROJECT Plan Prime Power KW Installation -KW Reservoir Elevo Ft. Storage -Acre Fto . Regulated Flow -cfs Stetson Cr. Diversion Ptarmigan Cr. Diversion Conduit Diameter Penstock Diameter Plant Factor Key: In. = Initial Ult = Ultimate {!-= D.P.R. #1 4,750 10,000 1,192 58,000 90 5'6" (5 '6 11 (4 '6" 47.5% H-22 #2 4,750 12,000* 1,192 58,000 90 5 '9" to (5'911 (l~ '9" 40% #3 #4 6,100 6,100 12,000 15,000 1,200 1,200 82,000 82,000 . 115 115 (In.No) (In. No) Yes Yes (In. No) (In. No) Yes Yes 6 1 0" 6 1 0" to(6 10 11 to(6 10" (5'611 (5 '6 11 (40% (32% Initial (50% (40% Ultimate F'ORTt..ANC • OREGON NOR T H PAC I F ICC 0 N S U l TAN T S ANCHORAGE. A!..ASKA [J u D D u u u u u u u U D D D u For the Cooper Lake project alone the installation will con- sist of 2 -vertical shaft, Francis type turbines rated at 8,400 H.P., 900 rpm and with an efficiency of 92%. The two generators will be 3-phase, 60 cycle, 7,500 kva capacity at 0.80 power factor operating at 900 rpm and with a voltage of 4,160. Their efficiency will be not less than 96% and their ca- pacity will be 6,000 KW eacho If it is decided to install initially for the ultimate development, correspondingly larger units will be required --2 -7,500 Kw generators operating at 4,160 volts. The ultimate installation will then be 15,000 KW at 40% plant factoro This plan assumes that Stetson Creek is not to be diverted to Cooper Lake and would conform to the details shown on the Definite Project Report drawings included in Appendix liN", except as noted below: (a) Conduit would be reduced from 5 1-9" diameter to 5 1-611 diameter pipe. (b) Penstock diameters would be reduced 311 on each section. The installed capacity would be 10,000 KW, using 2 -5,000 IDtI units, with a firm capacity of 4,750 KW and a load factor of 47.5%. 4. Plan IIA-2" -12,000 K"v'l -40% L.F. This plan assumes that stetson Creek is not to be diverted to Cooper Lake and would conform to the details shown on the Definite Project Report drawings included in Appendl..x "NIt without modification. The installed capacity would be 12,000 KW, using 2 -6,000 KW units, with a firm capacity of 4,750 KW and a load factor of 40%. 5. Plan "A-311 -129000 KW -40% L.F. ( Initial) • This plan assumes that Stetson Creek is to be added to the project. The details shown on the Definite Project Report drawings would be modified as follows: (a) The intake platform would be raised to elevation 1210. (b) Cooper Creek Dam would be construc+.ed to eleva- tion 1210 and the spillway would be excavated to elevation 1200. (c) Conduit and penstock diameters would be increased (d) Surge tank would be raised 10 feet. H-23 PORTI-ANO • OREGON NOR T H PAC I Fie CON S U L TAN T S ANCHORAGE. AI-ASKA D D D u u '1 lJ c 1 W u u u- u u D o u Installed capacity would be 12,000 ID~, using 2 -6,000 KW units with a firm capacity of 4,750 ~~ and a load factor of 40% initially. The increased reservoir capacity is required to provide regulation for the full development as previously discussed. In- cluding this storage initially, costs less than one-half of the cost if it were done when the diversion of Stetson Creek is accomplished and eliminates the need for building a concrete weir 8 feet high in the spillway channel. 6. Plan "A-4n -159000 KW -32% L"F. (Initial). Plan "A-411 contemplates addition of the Stetson Creek diversion and conforms to Plan IIA-Y' in all details except the fol- lowing~ (a) Generator capacity would be 2 -7,500 KW units. (b) Firm power capacity for the initial project would be 4,750 KW and a load factor of 32%. The ultimate project would be 6,100 Kli f'irm capacity and a load f'actor of' 40%. 7. Ptarmigan Creek. Ptarmigan Creek can be brought into aQY one of the initial .installations without modification of the physical features. The only change would be the addition of 265 K}l of continuous power capa- bility and the corresponding increase in the plant load factors. H. ULTIMATE JNSTALLATION The ultimate installation contemplates the diversion of Stetson and Ptarmigan Creeks, if Ptarmigan Creek is not included in the initial installation. 1. The Stetson Creek Diversion involves the following work~ (a) A diversion dam approximately one-half mile up- stream from its confluence with Cooper Creek. (b) A canal from the diversion dam to Cooper Lake approximately 1-1/2 miles longo 2. The Ptarmigan Creek Diversion involves the following work: (a) A small diversion dam approximately 1,700 feet up- stream from the conduit crossing on the Creek. H-24 PORTLANO • OREGON NOR T H PAC I f I ( ( 0 N S U l TA N TS ANCHORAGE. ALASKA Q W u u o u u u U J. u u . , u U J (b) A pipe line from the dam to the conduit line. (C) A small pumping plant to pump the run-off from Ptarmigan Creek into the conduit. 3. There are two Dlans which cover the ultimate install- ation possibilities. (a) Plan IIB-lII. This plan covers the addition of Stetson and Ptarmigan Creek flows, as outlined above to Plan IIA-3". The firm power would be increased to 6,100 KW with a load factor of·51%. (b) Plan "B-211. This plan covers the addition of Stetson and Ptarmigan Creek flows as outlined above to Plan IIA-4 11 • I. GENERATION CAPACITY 1. Cooper Lake Only. The desirability and economy of installing peaking capacity at Cooper L~e has been emphasized. It is estimated that such capa- city can be provided at the Cooper Lake project for about one-half the cost of thermal installations in the service area. Plate IIH-2" shows a possible operating procedure to utilize 3,000 KW of peaking capacity at this plant. It must be understood that such an operation does' not produce any additional KWH, in fact, slightly less, because of the increased friction losses in the water conduits during peaking hours. The continuous power available from Cooper Lake is estimated at 4,750 KW. To provide 3,000 KW peaking capacit,r for two hours every day throughout the year would reduce the continuous power to 4,500 KW, (about 5% reduction). The water saved by this operation would pro- duce 3,000 KW for two hours each day, (250 KW x 24 hours -3,000 KW), 2 hours which is a 30% increase in plant capacity. On the basis of a 50% load factor installation, the capacity for Cooper Lake need be on~y 9,440 KW. On the basis of the peaking system outlined, an installation of 12,000 KW is warranted. The peaking capacity'of this plant can be operated in any manner desired, and not necessarily at 3,000 KW for 2 hours each day as shown on Plate IIH-l". There are any number of ways in .mich it will be found to be useful. H-25 PORTL.ANO • OREGON NOR T H PAC I Fie CON SUI. TAN T S ANCHORACIt, AL.ASKA D U r 1 U o u IU W' I . r 1 'U u u u D o D u 2. The Full Project. The full project includes diversion of Ptarmigan Creek into the pipe line and diversion of Stetson Creek into the Cooper Lake Reservoir. The regulated flow available for power will be 115 cfs, completely controlled by storage. With such control, the ulti- mate installation may be large in comparison with the continuous prime power available. Plant factors as low as 25% or less are utilized on many hydro storage plants. With a continuous power capability of 6,100 KW, a plant factor of 30% would result in an installation of 20,000 ~1N. It is probable that this installation could be made at Cooper Lake project more economically than by thermal plants at load centers. However, a plant of this size would require increasing the size of tunnel, pipe line and penstock as well as the units, whereas a 15,000 KH plant could utilize the minimum size of tunnel, result- ing in maximum econolllY' of capacity installation. For this reason, an ultimate installed capacity of 15,000 ~v has been selected, re- sulting in a 40% plant factor. 3. Average Annual Generation. Because of complete annual control of its water supply this project has unlimited possibilities as regards station operation either as an individual unit or as part of a far-flung system. The installed capacity can be geared to any desired amount from an initial unit of 4,750 KWcapacity at 100% plant factor to two units of 7,500 KW each at 40% plant factor for the ultimate installation. 'llhere will be no secondary power from this project. All power will be prime power --available when desired --anytime. With the initial installation there will be about 41,500,000 KWH of energy available every year under the system load curve and therefore firm power. With a transmission line efficiency of 93% about 38,600,000 KWH will be available at load centers. For the ultimate project 53,000,000 KWH will be generated annually and 49,300,000 KWH will be avilable at market load centers, all prime power. II. PQT,<JER INSTALLATION A. TURBINES 1. Vertical shaft, single runner, Francis type turbines are considered the most suitable for this project. The turbine rat- ingsand operating conditions to develop 6000 KW at the generator shaft are as follows: H-26 PORn ... ND • OREGON NOR T H P A ( I F I ( (0 N S U l TAN T S ANCHORAGe:, ALASKA u·~ u D u u IU i I W ( 1'- IU 'J u u o D o Maximum net head Average net head (90 cfs) Minimum net head (180 cfs) Rating, at any head Rating at best gate Efficiency at best gate Speed 751 ft. 739.1 ft. 734.4 ft. 8400 hp. 7000 hp. 92% 900 rpm. 2. Selection of vertical type Francis turbines was made on the basis of economy, performance and the desired mechanical characteristics of vertical machines. Comparisons were made of hori- zontal and vertical types, both jet impulse and Francis turbines, and based on prelL~ary cost estimates received from manufacturers. The vertical machines including the generators are the most economical. These comparative costs are as follows: 7500 kva 0.8 P.F. 8400 hp. 2 Impulse 2 Generators 2 Francis Turbines Turbines Manufacturer Vertical Horizontal Vertical Horizontal Veit"tical Westinghouse Co. $305,000 $289,000 (450 rpm) (900 rpm) S. Morgan S. Co. $155,000 $171,000 . (900 rpm) (900 rpm) General Elec. Co. $278,900 (900 rpm) Allis-Chalmers $303,000 $285,000 $487,000 (450 rpm) (900 rpm) (450 rpm) (4 jet) Ne-wport Ship & $255,000 $280,000 Dry Dock Co. (900 rpm) (900 rpm) The costs received from the manufacturers have been adjusted where necessary to an 8400 hp. basis and to include coupling and turbine thrust provisions for the generators. Inherently the impulse type of wheel for this job would run at a lower speed which increases the cost of both the turbine and generator and also requires a larger powerhouse. Efficiencies of the two types of turbines for this installation are expected to be within 2%, which for the size of these units when evalu- ated on an annual cost basis, results in the Francis type being the most economical. The mechanical construction of vertical machines is also favored for this installation, over horizontal machines. In addition to a little higher efficiency, the alignment simplicity, absence of the H-27 PORTLAND, OREGON NOR T H P A ( I F I ( (0 N S U l TAN T S ANCHORAGE, ALASKA D U D u r 1 w . r I i~ u I r 1 U o o o o o critical balancing usually experienced with horizontal machines, economical provisions for accommodating the turbine hydraulic thrust, and the vertical arrangement of the turbine and generator are considered desirable. Although a lower powerhouse can usually be constructed with horizontal units, in this case it is planned to untank the transformer in the powerhouse which will dictate the height. Even though this contingency were not provided, the hori- zontal units would require a lOnger powerhouse which would offset the savings. Another factor usually favorable to horizontal units is convenience of disassembly. The necessity of having to completely pull the turbine wheel is very remote, or at least very infrequent, and therefore this is not considered to be a pertinent factor. In order to firm up the manufacturers prices and data em- bodied in this report, alternate bids could be taken on horizontal and vertical 900 rpm turbines. This will require very careful analyzing of ~he bids and preparation of the specifications to in- sure that equal eqUipment and characteristics are being furnished by the low bidder. Also, the cost of the powerhouse for each type would need to be considered when making the evaluation. Setting up alternate proposals such as this always imposes complications, and is not considered necessary since the preliminary studies made in connection with selection of turbines for this report dictate the installation of Francis type vertical units which are recommended. B. GOVERNORS The governors are to be of the vertical gate-shaft type, oil pressure operated, complete with motor driven governor head, speed level device for remote control, speed droop device, gate limit device for remote control, shutdown device for remote control and handwheel for manual control at the governor. All devices are to be controlled from a remote point and will also be capable of being con- trolled manually at the governor. Each governor will also have an oil pressure tank and sump for receiving return oil, and a motor driven oil pump to build up the pressure in the pressure tank to be- tween 150 psi and 200 psi. c. SHUT-OFF VALVES Pressure regulators are not required since a surge tank will be provided to reduce water hammer to the penstock design pressure limitation. Each turbine will be provided with a 30 ft motor operated valve designed to stand full upstream pressure but will either be in the fully open or closed position. The valves will not be required to regulate water flow to the turbine. The valves will be capable of being closed to cut off the water to the turbine in the case of turbine failure. H-28 PORTLANO • OREGON N 0 RT H P A CI F IC CON S U L TA N T S ANCHORAGE. ALASKA D u u u u U : v: .... -' u u u , l U o o o D. GENERATORS The generators will be vertical shaft, water-wheel driven type, with thrust bearing, two guide bearings, direct connected main and pilot exciters, voltage regulator, excitation cubicle and open type ventilating system. The rating and characteristics of the gen- erators are to be as follows~ Capacity, leva Power factor Frequency, cycles Ntunber of phases Voltage between phases Speed, rpm Short circuit ratio Line charging kva, over Efficiency, 3/4 load Transient reactance 7,500 0 .. 80 60 3 4,160 900 Unity 6,000 96% 36% The generators are to have Class B insulation and the max- imum temperature rise for both the armature and field windings will not exceed 60 degrees Co Each generator will also have a WR squared value of not less than 65,000 ft .. squared Ibs o The deciding factor leading to the selection of vertical generators was mainly a matter of economy considering the turbines and powerhouse as discussed under turbines above. Comparative costs of horizontal and vertical generators are shown in sub-paragraph "A" above. The armature winding will be wye connected and the neutral will be either solidly grounded or grounded through a neutral reactor if required to limit the line to ground fault current to the three phase winding current which will be determined when the final react- ance values are available .. On the basis of overall plant economy and suitability, the voltage of 4160 has been selected for the generation voltage. The corresponding BIL for this voltage is 60 lev and the reference class is 5 kv. The comparison of the three voltages (4160 volts, 6900 volts and 13,800 volts) showed the 4160 installation was the cheaper by $32,000. Eo ELECTRICAL EQUIPMENT 1.. Nain step-up Autotransformer .. The plant output will be delivered to the external trans- mission system by a three phase autotransformer rated 12,000 kva OA/15,oOO kva FA-T, 4.16 -69/115 kv, 55 degree Co rise. A saving H-29 PORT:. ... NO • OREGON N 0 RT H PAC I FIe CON S U L TA N T S ANCHOR ... GE. AL ... SK ... w u u u : 1 W , ( 1 I I \W i iU ( ). I ~J i f 1 ~ ( 1 l..l \ . r ) :U I U U u u J of approximately $50,000 is realized by using a three phase trans- former compared to using three single phase units, plus a spare, in this case and the three phase type transformers have an excellent record of service reliability. Spare parts for the transformer in- cluding some coils will be stocked at the power plant. The powerhouse crane will be sized to permit pulling the core and coil assembly to permit convenient and speedy inspection and repairs if the need ever arises. Also a nitrogen blanket of gas will be provided to minimize oil contamination and lessen the danger of fire inside the case. The low side delta will be made inside of the transformer and connections to the power switchgear will be made by metal en- closed insulated phase bus. 2. Generator Switchgear. Metal clad switchgear and metal enclosed, insulated bus has been selected for its reliability, suitability and economy for the station. The switchgear and external bus is to have a BIL of 60 kv corresponding to the voltage reference class of 5 kv. The circuit breakers are to be rated 5 kv, 1200 ampere, 250 Mva. Each generator is to be connected to its switchgear by 1200 ampere metal enclosed, insulated phase bus o The bus extending to the main step- up autotransformer is to be 3000 ampere bus with the portion outdoors to be weatherproofed and externally insulated to prevent condensation inside the enclosure. The switchgear sections are to include only the 5 kv eqUipment with local test control switch as all control devices, instruments, relays, meters are to be mounted on the duplex switchboard located on the floor immediately above. 3. Station Service Power. Station service power is to be supplied from a station service transformer rated 150 kva, 4160 -480 volts, dry type located integrally with the 4160 switchgear. A combination station service switchboard containing feeder air circuit breakers, motor starters, contactors, a lighting transformer and attached 120/240 volt dis- tribution switchboard will provide service for station power for the auxiliaries, lighting, heating and low voltage equipment. In gen- eral, all motors one horsepower and above will be served by 480 volts and 120/240 volts will be used to serve smaller loads. A standby diesel electric generator set will be provided for starting up the plant. The set will be equipped to start and stop automatically when normal station service power fails and re- turns. Only essential auxiliaries will be connected to the standby set. The set is to be rated 25 kw, 0.80 p.f., three phase, 480 volt, 60 cycle. The set is to be furnished complete with all required con- trol equipment including voltage regulator, start batter!, charger, and auxiliaries to provide an entirely independent source of standby power. H-30 FORTI-... ND • OREGON NOR T H PAC I FIe CON S U l TA N T S ANCHOR ... GE, AI-... SK ... Q (-1 ~ i 1 ~ I U '0 U U :U U ( ). I.J [ \ U ( 'I W IU I U U r ---..~ W D 0 U ) I 4. Lighting System. Normal powerhouse lighting will be supplied from a single phase, 10 kva, 120/240 volt, 3 wire, drY type transformer which will be located adjacent to the main 480 volt distribution switchboard. Emergency lighting from the station battery will be provided in critical areas to provide minimum adequate seeability. An automatic transfer switch will be provided to switch to the emergency supply when the normal supply fails and return to normal when the normal supply is restored o For the normal lighting 20 foc. will be provided for the < generator room area, 30 f.co for the control room and office, 15 f.c. for the turbine floor and battery room and 5 f.co for all other areas. Floodlights will be provided for the exterior areas where required. Hi-Bay fixtures will be used for the generator room; in- dustrial fluorescent for the generator switchgear area, machine shop; and office type for the control room and office. RLM type fixtures will be used in other areas. Local convenience outlets and switching will be provided for 120 volt and 240 volt equipments in addition to 480 volt out- lets as required. 5 e Powerhouse Grounding. A suitable ground mat will be provided for the powerhouse having an effective resistance of not more than 0.50 ohms. The ground mat will consist of driven ground rods in a low resistivity area and the rods will be interconnected by copper cables attached by the Cadweld welding process. Four main copper cable risers will be used from which tape will be run to all metal parts to hold these parts to practically ground potential. Connections and ground wire size will conform to applicable codes and practices. 6. Plant Control. In addition to manual control of each generator at the powerhouse, supervisory control is provided for manual remote con- trol of the generators from Anchorage over the 115 kv transmission line by carrier current. The one-line diagram shows the points to be under supervisory control and the information to be telemetered to effect the remote control operation. Starting and stopping of the units is accomplished by ener- gization or de-energization of a start relay. Before this start re- lay can be energized all auxiliary equipment essential for proper operation of the units must be in operation as well as re-set of the lockout relays. Correct startir~ of a unit is also monitored H-3l PORTl. ... ND, OREGON NO RT H P ACH Ie (0 N S U l TA NT S ANCHOR ... GE, Al. ... SK ... (, w III U I :U W u u . ~ ) :U I U ( i I i ~ u ( , IW I !U u u o 10 by a correct sequence relay.. After the machine is started and comes up to synchronous speed, the automatic synchronizer may be cut in from the controlling point and the unit will be synchronized auto~ matically and connected by its breaker to the step-up transformer .. Loading of the machine is then accomplished by adjusting the speed to the desired level from the controlling point by means of the speed level adjusting control over supervisory. Various ab- normal conditions at the plant through lockout relay contacts will stop the units or bring them to the speed-no-load position depending on the nature of the trouble. The abnormal conditions causing this operation are shown on the one-line diagram.. After the occurrence of an automatic complete shutdown, the lockout relays must be re- set manually at the plant for safety reasons. Communication between the controlling point and the plant will be provided by carrier current communication transniitter re- ceiver sets. This ,nll be provided over a separate channel from the telemetering and supervisory functions over a single frequency sim- plex automatic type carrier set with code bell ringing .. Continuous telemetering for the ten points shown on the one-line-diagram is to be provided by a separate telemetering trans- mitter by tone modulation of the carrier frequency or equivalent means. This is standard equipment for this function and is furnished by several manufacturers. 7.. Duplex Switchboard. The duplex control switchboard will contain the control, meters, instruments, relays, recorders and supervisory control equip- ment for control of the units, station service feeder, intake feeder, transformer, switchyard and Cooper Landing feeders. The switchboard will be located in the control equipment. This board will have only low voltage circuits at 125 v.doc .. and 120 v.a.c. Sufficient mount- ing space for all control equipment is afforded by use of a central- ized control switchboard which cannot be provided on generator switch- . gear for the control equipment required for this plant. 8. Station Battery, Chargers, and Control Cubicle .. The station battery will consist of 60 cells, nominal 125 v.d.c .. , having a 35 ampere 8-hour rating.. The battery charger will be a diverter pole type m-g set driven by a 480 volt, three phase motor. The generator will be 3 kw and the motor 5 hp. The rotating type battery charger was selected because of its long life.. The diverter pole type charger was selected because of its excellent characteristics for floating service. An inverter set will be provided for standby 120 voa.c. for operation of the carrier current sets, recorder motors, clocks H-32 PORTI.."NO • ORE:GON N 0 RT H P A Cl F I ( (0 N S U L TA N IS ANCHOR ... GE:, AI.. ... SK ... J iW I iW I ',U' , I I I 'U \ U I I 1 I 1. I~r o u and selsyns. The generator will be rated 3 kva, 1 phase, 120 v"aoc. and will be driven by a 125 v.d~co motor. The inverter will be automatically cCTh~ected to the station battery when the normal clock bus supply fails ~~d will be shut down automatically when the normal supply is restored. A c'Jpper oxide or selenium type charger will be provided for charging the 48 V. supervisory battery. The control cubicle ~~d distribution board will contain the automatic control devices and meters for control of the inverter set, battery chargers and the 125 v.doc o and 120 voa.c. distribution circuit breakers.. The 480 volt starter for the diverter pole charger will be mounted separately near the set. Only 125 v"d .. c. and 120 v.a .. c. circuits are to be run in this cubicle. 90 Electric SeI""lice to Intake, Surge 'i'ar.k:, Operator's Residences .. A three phase, 4,160 volt line will be provided to serve the operator's residence, surge tank heaters and the intake works .. Pole mounted distribution type transformers will be provided to step down the voltage as required.. The line will be dead-ended at the powerhouse structure from wtdch point cables will be run to the feeder breaker cub:1..cle in the powerhouse.. Lightning arresters will be provided on the first pole structure near the powerhouse.. The line will be a single wood pole construction designed in accordance with N.E .. C. Standards. A ?-pair supervisory control cable suspended by spiral messenger steel ribbon will be r~ on the 4,160 volt pole line to control the intake gate motor and telemeter the intake water level to the powerhouse.. The head water level transmitter will be of the re-transmitting, slidewire type w~th local pointer dial and the recorder at the powerhouse will be of the null balancing potentio- meter type. Supervisor,! control for the intake gate motor will be accomplished by standard supervisory type relays at 48 volts d.c .. 10. Mechanical Eauipment. The powerhouse will be provided with the following mech~~i cal equipment: (a) CO tw'J fire extinguishing equipment for the generators and portable hand extinguisrdng equipment .. (b) One 25-t:m bridge crane for untanking the main pmN'er transformer and assembly of the units and other miscellaneous equip- ment handling. (c) One station ci:rai."lage sump pump and motor .. H-33 PORT .. 4NO • OREGON N 0 RT H P A CJ F IC CON S U l TA N TS ANCHOR4GE. A .. 4SK4 : 1 U u r I U r 1 W u , ' U I ' I U lU' I ' \ 'U r 1 U u rl U o o o u (d) (e) (f) (g) purifier .. (h) water. (i) (j) (k) lathe, shaper, Generator cooling water pumps if required. One 100 psi station air compressor and receiver. One lubricating oil storage tank. One portable insulating oil and lubricating oil Necessary purification equipment to provide potable Septic tank and effluent chlorinator. Unit type electric heaters and ventilation fans. Nachine shop equipment consisting of hand tools, cutoff hack saws, grinder, welder. H-34 PORTl.. ... NO , OREGON N 0 RT H PAC I F I ( ( 0 N S U l TA NT S ANCHOR"'GE, AL ... SKA 10 I J ,. '. ! W U 0 U r 1 W U r , U , 1.· ; ( I U . IU I I I , r 1 IW I U U D J U n ~f IW :2. I--... ~ ~ '-l ~ COODEQ LAKE Pt20JECT PROJECT PLANT OPERATION To Furnish 3000KW Peak, 2 firs. Dai~l.J Above Re u/ar Jj sfem Load OperatIon " o " Jan. F'izb. Mar. Apr. Jllcgy JUM July AU9' Stlpt Oct. Nov. Dec. MONTHS Norfh Paciric Con::Jul/anf5 Pla/eNo. H-J I IW I I Ut , IJ :J I J :U I i J U !J \ f '!:" i U 'U I iU I I J : : 1 w u ;J IU J IJ I COOPER LAKE PROJECT PEAK DEMAND-K.W ~ CAPABILITY Palmer., Anchorage, Seward and kenai Peninsula Area o /.95;" '55 /9~6 '57 /958 J '59 1960 ,~~ YEAR Norlh Pacific Consullanfs 1962 '63 1964 '65 Plale No. H-2 I ~ U[ 7 U U U U U 'U I iU I I:' V· l.r- iU I :U I I I I J iJ U :J I J . ~J-- U L 250 200 /50 100 I I I ;,1 50 0 COOPER LAKE PROJECT ENERGY REQUIREMENTS &, CAPABILITY Palme;; Anchorage" Seward and Kenai Peninsula Area . / , / ./ V ,,-\ ", ,-----/--. --1---I---- v\ -f.'<-"," 5 / \. ~'r~ ." " In 'P.( , "rl ;/ / I 1(/0 '!..\u / u\~ Itft/' ~T.E f4M 85: DoO,. DOO o· all v ~<J P~a.~ tr-'" \~ / <;.,~ ~ \\~ r-.~V\\' \'" /1 _ h.~~ 0/ ,::; . / V 1<Y"' l> ~ "> ~~i ~~ C ~£~ ICE/\ rL lAKe =2~ 00<. \V j<1; / 000 ~ "G if / V/ (k inin um iLleal t-witt lin, l/ff2Q sta II ~/ 5 rrET.. ~ON CRt. EK, F/~j POD k70c KH "I I / I V ICo OP.E IR~ AKl. =4~ OOQ ~oo KJV. I // VC:? r.7 !led 'rj I -'" -/ I 10-t: 'TN ~ :: I ~aC POD KW. 'I I /"" KLl. oac /' lIn miT. Imu ~!:I ~8r) 350 ~oo -- 'vWH ~;; Vi ~ /952 53 S4 .55 56 57 58 59 /%0 (0/ 62 63 (;4 G5 ~~ /967 YEAR Norlh P8c/fic Consulf8nls Plafe No .. fI-3 ~ o u D APPENDIX "III u STRUCTURAL DESIGN u CONTENTS U Page u , , : I lJ ( ~, u D D U· U 1. Structural Design A. General --------------B. Dam ------- --- ----- C. Intake Structure ---- D. Conduit ------- E. Surge Tank --------- F. Penstock ------------ - ---- - G. Powerhouse ------------ PORTI-ANO , OREGON NOR T H PAC I F I ( (0 N S U l TAN T S ANCHORAGE, AI-ASKA 1-1 1-1 1-1 1-2 1-2 1-3 1-3 o r ' u u o D o o u I. STRUCTURAL DESIGN A. GENERAL The structural features of the dam, intake structure, tun- nel, conduits, surge tank, penstock, powerhouse and minor structures in connection with the road and conduit construction have all been analyzed on the basis of accepted engineering practice and in ac- cordance with the applicable standards of the American Concrete In- stitute, the American Institute of Steel Construction, the Uniform Building Code of the Pacific Coast Building Officials Association and the Manual of Design Standards of the U. Se Army Engineer Corps. Structural concrete has been based on a 28-day strength of 3,000 psi and mass concrete 2,000 psi, structural steel 20,000 psi, reinforcing steel 18,000 psi, welded steel pipe in the conduit and penstock and surge tank 15,000 psi. Seismic forces have been taken for those set forth for Zone #3 in the Uniform Building Code e B. DAM (See Plate VIII) The earth and rock fill dam has been designed to obtain a minimum factor of safety of 1.6~ Laboratory test data on samples of materials proposed to be used are not available'~ Samples were taken and delivered to the laboratory for test and the results will be made available latero Visuai examinat{on in the field indicates that ample material of low permeability and good shear strength are available. Also ample amounts of fine rock fragments are obtainable by selective borrowing in the immediate vicinity, for the central portion of the damo Rock from the spillway excavation and coarser gravels from the glacial outwash will be used in the downstream third of the damo The design shown on Plate VIII will have a factor of safety of well over the desired 1.6 with the material seen in the field o However, actual borrow areas will be selected and the mater- ials tested so that the actual factor of safety can be computed. This work will be accomplished during the design. Co INTAKE STRUCTURE (See Plate IX) The intake will require a minimum amount of structure con- sistent with proper functioning. The invert has been set at eleva- tion 1155, 12 feet below the minimum pool level of 1167. Trash racks have been provided to a width of 16 feet. Stop logs are provided ahead of the gate to allow de-watering and access to the gate for maintenance purposes. A baffle wall extending to 5 feet below low water ahead of the gate is provided to close the space around the 1-1 F'ORTt.ANO • OREGON N a RT H PAC IF ICC 0 N S U l TA N T S ANCHOR~GL At.ASKA J i 11 ~,r U u u U IU I 'W I r ' .... IU. i ( 1 U ( \ ; I W o o u gate so a minimum of heating will be required to keep it free from freezing" The intake structure is of reinforced concrete providing a transition from the 16 foot wide trash rack opening to an 8 foot 6 inch gate. An approach ch~~el will be excavated to a depth of 15 feet below minimum pool. Access to the structure and gate is pro- vided by a fill placed 13 feet in width and at an elevation of 1200 extending from the shore" The necessary fill will be obtained from the tunnel spoil. D. CONDUIT (See Plates IX and X) The conduit extending from the intake structure to the surge tank a distance of 7818 feet consists of 120 feet of 7 foot diameter concrete pipe, 5600 feet tunnel, rough excavated to an 8 foot diameter horseshoe section, 2048 feet of 5 foot 9 inch diameter steel pipe laid in a trench with a 3 foot cover and 50 feet of tunnel to the surge tank. To provide structural strength and prevent the loss of water through sections where the rock may be fractured and at the tunnel ends where the cover is light, the tunnel will be lined with concrete and reinforced 0 The westerly 300 feet of .the tunnel will be a lined circular section 7 feet in diameter. The central section 4900 feet in 1 ength will be unlined except that provision has been made in the calculations and estimates for lining 20% of this distance with concrete sho.uld the nature of the rock at contact zones require support. This lining will be to a 7 foot horseshoe section. The section of tunnel beneath the surge tank will be a 7 foot diameter, concrete lined and reinforced tunnel. The 8 foot horseshoe section has been selected as the most economical size to construct. The steel conduit diameter was selec- ted for economy,based on pipe costs and power values. Pipe thick- nesses have been increased 1/8 inch to provide for corrosion. Butt welding of pipe sections was selected for economy and safety taking into account the fact that welding equipment is required for the penstock. Eo SURGE TANK (See Plate X) The surge tank was located on the highest ground available adjacent to the powerhouse and placed directly over the conduit" The design was based on an effective gate opening or closure time of 6.7 seconds. For maximum surge upward~ entire closure of the gates of both turbines was considered, for the downward surge bringing one unit up to maximum power output in 6" 7 seconds. The tank would be 15 feet in diameter and extend to elevation 1214 requiring a steel structure approximately 54 feet above the ground and an excavation of this diameter into the rock to the conduit tunnel beneath. The I-2 PORTI-ANO • OREGON NOR T H P A ( I F I ( ( 0 N S U L TA NT S ANCHORAGE, A1...ASf(A u D U U u ( 1 W r ) U o D o o J tank would be designed as a differential surge tank with a 5'-0" di- ameter central column. Protection against freezing would be accom- plished by enclosing the above-ground tank with a wall providing a small annular space between it and the tank. Heat would be provided by electric heaters thermostatically controlled. F. PENSTOCK (See Plates IX and X) The penstock extends from the surge tank to the powerhouse a distance of about 2455 feet. It consists of 150 feet of tunnel with a reinforced concrete lining providing a 7 foot diameter circu- lar section and welded steel pipe varying in diameter from 5 '9" to 4 '9". The pipe will be placed in a trench with 3 feet of cover and anchored with concrete anchors against all forces. Estimates are based on butt welded steel pipe, the steel having an ultimate strength of 55,000 to 65,000 psi and a minimum yield of 30,000 psi. Plate thicknesses have been proportioned for maximum net heads including water hammer for an effective gate closing time of 6.7 seconds and increased 1/8" to provide for corrosion. Butt welded joints were selected as a safety measure for the high head pipe. Since welding equipment and skills are required for the high pressure section, it was determined more economical to use welded joints throughout the pipe system. G. POWERHOUSE (See Plate XI) The powerhouse was located along the shore of Kenai Lake where the entire structure will rest directly on the rock and the tailrace would be in rock. The penstocks leading to each unit are in trenches excavated below the general building foundation level and the trench backfilled with concrete thus securely anchoring the conduit to the rock. Passageways to receive the discharge water from the draft tubes extend into the lake to allow free flow of water and deep enough to avoid ice damming. Support for the tur- bines is obtained by casting a 5 foot thick concrete monolith di- rectly on the rock. The building itself is designed of reinforced concrete using the following loads: (a) Dead loads. (b) Weight of all machinery and equipment. (c) Floor loads of 300# per square foot in addition to allowances for specific spot loads. (d) Roof load of 100# per square foot. (e) Wind velocities of 100 miles per hour. 1-3 PORTl. ... NO • OREGON NOR T H P A ( I F I ( ( 0 N S U t TAN T S ANCHOR ... GE. Al. ... SK ... o u u f ) U u u (l U o Q (f) Crane loading of a 25 tone crane with a 25% impact allowance (the weight of the longest piece of the equipment) • (g) Seismic or earthquake forces. The building includes, in addition to space for two turbine and generator units, a work bay of assembly and repair, a shop and storage area, a control room, office and other necessary facilities. The estimates provide for sealing, insulating and heating the control and office areas and for necessar.y lighting and plumbing facilities. A large steel roll-up door is provided for handling equip- ment in and out of the powerhouse~ A 25 ton capacity crane is pro- vided for servicing turbines, generators, transformers, etc. Stair- way and removable slabs are provided in the generator room floor for access to and removal of equipment for renewal or repair. 1-4 PORTL ... NO • ORI!.GON NOR T H PAC I Fie CON S U l TA N IS ANCHOR ... GE, AL ... SK ... o u u u u r ) u u I ' :u I iu i i ( 1 LJ u u o u APPENDIX II JII PLANT OPERATION AND I1AINTENANCE CONTENTS A. General - - - - - - - - - -J-l B. Automatic Operation - - - - - - - - - - - - - - - - - - -J-l C. Semi-Automatic Operation J-2 D. Cost of Operation and Maintenance - - - - - - -J-2 PORTL.AND • OREGON NOR T H P A ( I F I ( ( 0 N S U L TAN T S ANCHOR"GE. AL.ASKA o 0, (~ ~ u u u u u u U iU I , r 1 I W 'U U D o PLANT OPERATION AND MAINTENANCE A. GENERAL The proposed plan of operation and maintenance is out- lined under Paragraph nB", I1Automatic" below. The characteristics of the load which the plant is to supply and system load curves are shown on Plates fIH-l" and "H-2!!. Discussion of alternate sizes of units to fit the load curves is included under Appendix "H". B. AUTOMATIC OPERATION 1. Load changes will be made automatically by governor action under gate limit control and speed level adjustment. Full automatic control of load changes from head water or tailwater water levels is not required or applicable to this plant since water regulation is not a determining factor. For initial start an oper- ator is required to open the intake gates from the plant, open the valve at the turbine, check all auxiliaries and from this point on, units may be started automatically at the plant or from Anchorage by energization of the \lstart-stop" relay.. After machine speed is reached and voltages are correct, the unit will automatically be synchronized and connected to the liQe. Load will then be received by the unit in accordance with the gate limit and speed level ad- justment setting. After the initial start, or until the intake gate has again been closed and turbine valve closed, the unit may be shut down or started up again by operation of the II start-stopll relay.. . 2. To effect this degree of automatic control the super- visory equipment and carrier current equipment is estimated to cost $32,000. With the controlling point in Anchorage, system operation can be effected from one point, eliminating the need of shift oper- ators at various points on the system, thus reducing operating costs. The economy of centralized control, as proposed for this system and plant, is a well known fact and is easily justified.. Shift oper- ators would be required at Anchorage only for operating the entire system by automatic supervisory control. Even though operators were provided solely for this plant at Anchorage, the cost of five, oper- ators at the site and the cost of residences for the personnel would by far exceed the initial investment of $32,000 for the automatic equipment.. Also, the anticipated personnel turnover would be high, adding to operating costs. Such problems as schools, supplies and isolation would make staffing a continuous problem. Cheaper hous- ing, a lower wage scale, schooling facilities, security and access to supplies would all add to the operating efficiency and eeonomy of centralized control in Anchorage. The greatest economy will be realized, however, from centralized control by eliminating dupli- cation of operating personnel when additional plants are constructed. J-l PORTLAND. OREGON NOR T H PAC J Fie CON S U L TAN T S ANCHORAGE. ALA51<A o II _ \.J,r u o u u u lU I ( \ J o o n W o 34 The following generator readings would be telemetered to the central dispatching office at Anchorage for control of the units: Megawatts Megavars Voltage Speed Gate Limit Setting These values would be on a continuous telemetering basis by carrier current over the 115 kv transmission line~ The head- water elevation, tailwater elevation and turbine Q would be trans- mitted to Anchorage by supervisory on a point selection basis4 4e Supervisory control of the plant will be accomplished as shown on the one-line diagramo The supervisory equipment will be of the standard type similar to Hestinghouse Electric Corporation "Visicode" employing point selection, cheQk back and permissive operation. The equipment will operate on carrier current over the transmission line to Anchorage on an independent frequency in the range of 50 to 150 kc. Microwave equipment was considered for this function, but due to the higher cost of the equipment and added maintenance cost of a repeater station, this method of transmission for supervisory control was not adopted. 5. For the plan of operation proposed, the plant should be attended by an operator and maintenance worker. Residences have been provided near the powerhouse site for operation personnel. From a security standpoint,' it is preferable to have personnel at the site. This report includes the cost and service facilities to provide two at-site residences. C. SEMI-AUTOMATIC OPERATION Semi-automatic operation as such is not proposed for this plante After the initial start, the units may be started or stopped from the plant or from Anchorage by supervisory control. Automatic shutdown from water control is not applicable since the prime re- source is a storage reservoir and close water regulation iS,not required. Do COST OF OPERATION AND MAINTENANCE The cost of operation and maintenance has been estimated and included in Appendix "M". J-2 PORTI. ... ND , OREGON N 0 RT H P At IF I ( (0 N S U l TA N T S ANCHOR ... GE:, AI. ... SK ... u u u I 1 U u u- I 1 ) I ~ u o u o o u APPENDIX "K" FEDERAL AND TERRITORIAL JURISDICTION CONTENTS I. Federal and Territorial Jurisdiction A. U. So Forest Service - -------- ----K-l B. U. S. Fish and Wildlife Service -_.--K-2 C. U. S. Federal Power Commission - - -K-3 D. U. S. Geological Survey ----K-4 E. Other Agencies -- -------K-5 PORTL. ... NO , OREGON NOR T H PAC I Fie CON S U l TAN T S ANCHOR ... GE, AL. ... SK ... o o u u , 1 W u u u f ' U u o o o I. FEDERAL AND 'l'ER.1ITTORIAL JURISDICTION Certain permits, licenses, franchises, and other authori- zations are to be obtained from various Governmental agencies by the Central Alaska Power Association (and the Chugach Electric Associa- tion) before construction of the proposed hydroelectric project may be commenced on Cooper Lake. Following is a brief discussion of these authorizations and permits. A. U. S. FOREST SERVICE The entire project area is within the confines of the Chugach National Forest, administered by the U. S. Forest Service. Several items relating to both construction and operations therefore are within the jurisdiction of this Serviceo 1. Access. Access to project sites for construction and operations: Discussions have been held by the Engineers and members o£ the CAPA staffs regarding the planning and provision of access and other roads to the various project sites, i.e., dam site on Cooper Creek at the outlet of Cooper Lake; power house site on Kenai Lake; pen- stock, conduit, surge tank, tunnel and intake from Cooper Lake to Kenai Lake; and access to the suggested future diversion of Stetson Creek. It will be necessary for CAPA to continue discussions with staff members of the U. S. Forest Service (through its local repre- sentative in Seward and the Regional Forester's office in Juneau) regarding these items 0 It may be pointed out that, during previous conferences, the utmost of cooperation was offered by the Service both to the Engineers and CAPA staff members so that no undue dif- ficulties will be encountered. It must also be pointed out·that the provision of such access roads appears to be in 'concert with plans of the U. S. Forest Service to make possible the full use of the Cooper Lake area for recreational purposes. The Service has planned a service road southeastward from Snug Harbor on Kenai Lake toward the proposed power house location. Joint planning and con- struction of this particular road facility would therefore be in- dicated, as well as possible cooperative sharing of costs. The provision of a service road beyond the power house site, up and across the saddle separating Kenai and Cooper Lakes should also be planned cooperatively. 2. Possible Clearing of Reservoir Area. Discussions of this matter were carried out on several oc- casions by the Engineers and members of the U. S. Forest Service. K-l PORTLAND. OREGON NOR T H PAC I F I ( ( 0 N S U l TAN T S ANCHORAGE. AL.ASKA o D u u u u u u. u u u u D n U Inasmuch as the normal level of Cooper Lake is proposed to be raised, portions of the basin will be flooded. A general consensus appears among the Engineers and the members of the U. S. Forest Service staff, tliat the amount of timber land to be thus inundated is very small, and that the timber thereon is of very little or no commercial value. However, a final determination of requisite clearing should be made between CAPA and the U. S. Forest Service representatives prior to construction. As in previous conferences, the utmost of cooperation has been evidenced, and no difficult,r should be encountered regarding this matter. 3. Utilization of Timber for Construction. Although, as pointed out, there is relatively little -- if any --timber of commercial quality and accessibility, discussions should be held with representatives of the U. S. Forest Service re- garding the location of tL~ber which might be appropriately available for construction material during the building of the proposed pro- ject, and the manner in which such timber might be cut and utilized. Inasmuch as the Cooper Lake and Kenai Lake areas admittedly are of superb scenic value and will provide unusually excellent recreational opportunities, the construction o£ the proposed project should be so planned as to detract to a minimum from the natural scenic values of both lakes. The advice and cooperation of the Ue So Forest Ser- vice should therefore be sought relative to planning and con- struction. Architectural designs of structures should reflect a recognition of scenic values to the extent practicable, bearing in mind that a good architectural design costs no more than a poor one. The extent to which the establishment of construction camps on both Kenai and Cooper Lakes may be required should be co- ordinated with the possible establishment of longer-range recrea- tional facilities, if these are contemplated. Pollution and fire prevention measures should be given fullest consideration by co- operative conference with the U. So Forest Service. B. U. S. FISH AND WILDLIFE SERVICE The Preliminary PeI'1llit (Project No o 2170) issued by the U. S. Federal Power Commission on the proposed Cooper Lake hydro- electric project st1.pulates under Article 10: liThe Permittee shall during the period of project planning cooperate with the U. S. Fish and Wildlife Service and the Territorial Agencies concerned with the management of fish 'and wildlife resources with the specific intent of developing a plan least harmful to these resources, giving primary consideration to the maintenance of adequate flows in Cooper Creek to preserve its salmon-producing capacity and sport fishing potential and such mitigation measures as may appear desirable and reason- able ••• " K-2 PORTLANO , OREGON NO RT H PAC I Fie CON $ U L TA N T S ANCHORAGE,. At-ASKA u u o u , ) u u u u u { i U U o o o o Numerous conferences were held by the Engineers with rep- resentatives of the U, S. Fish and Wildlife Service on this subject~ so that both parties might understand and recognize each other's views and suggestions. Excellent cooperation was obtained by the Engineers from staff members of the Service, and mutual problems were e:xplored on seve:r'al occasions. As a result of such conferences, the Engineers undertook special measurements of flows below the site of the p~oposed dam structure so as to provide a basis for estimat- ing residual flows once the proposed dam structure is erected. An- ticipated lake level fluctuations were also reviewed in a preliminary manner. The Engineers believe that residual flows under suggested operating conditions, primarily from small streams and ground-water sources below the site of the proposed dam structure, will provide minimum winter flows for spawning grounds and sport fishing nearly equal to the existing natu:-al flowso The spring and summer freshets, under the suggested operating conditions, will be reduced by project storage, which should improve this condition for the fishery. It is suggested, however~ that further discussions be held by CAPA with tJ'o S. Fish and Wildli£e staff' and corresponding Terri- torial agencies on the basis of the detailed conclusions contained in this report. It is the Engineers~ belief that measurements of winter water and ice conditions in the very lower stretches of Cooper Creek just above its confluence with the Kenai River are necessary to determine existing spa\ining bed conditions prior to the proposed operation of the projecto This is due to the fact that there exists no information at this time as to how ice now affects spawning beds. Stream measurements are being made by the U. So Geo- logical Survey (\V'inter 1955-1956). There appear to be no questions regarding the effect of reservoir level operations in Cooper Lake itself. Inasmuch as both the Uo So Forest Service and the U. S. Fish and ~vildli!e staffs are favorably interested in the opening of the Cooper Lake area for recreational purposes, it is recommended that collaborative discussions and planning as described in para- graph A-3, above, include fish and wildlife aspects as welL Co U. S. FEDERAL POlVER COHHISSION A license for the proposed project will be required from the U. S. Federal Power OJrnmission under the specific terms of Section 131.2; Sections 4~O, 4.41; 4.42 of the tlGeneral Rules and Regulations including Rules of Practice and Procedure under Part I of the Federal Power Act" (as amended under F.P.C o Order No. 175, docket No. R-128, issued Mlg'J.st 12, 1954). K-3 PORTL.. .... NO • OREGON NOR T H P A ( I F I ( (0 N S U l TAN T S. ANC ... OR .... GE. AI-.... SKA o u u u u u u r 1 U u u u o o o u The sections referred to above spell out concisely the contents, required exhibits, and specifications for drawings of the application. Because of the fact that the Preliminary Permit (Project No. 2170) was issued by the U. S. Federal Power Commission to the Chugach Electric Association, it will be desirable for Chugach to apply for the applicat.ion for a license. By so doing, continuity of the priority thus established will be maintained. Shortly after the filing of this application, upon acknowledgment of receipt thereof by the Federal Power Commission, a supplemental applica- tion should be filed by Chugach Electric Association on its own behalf and in behalf of Central Alaska Power Association, pointing out the fact that Chugach is a member of CAPA. At the same time, Central Alaska Power Association shall make all necessary showings as requested of any applicant for a license. This supplemental application should be signed by both Chugach and CAPA, be notarized and verified in the same manner as the original license applica- tion. This is required because preliminary permits issued by the Federal Power Commission are non-transferable instruments. In the event it is determined by CAPA, that the Stetson Creek diversion should be included in the overall project, an application for an amendment to the existing license will be re- quired to have the diversion included as a part of the licensed project. Prior to that time, it will be desirable to satisfy the U. S. Fish and Wildlife Service and corresponding Territorial agencies that the diversion will not adversely affect fisheries resources. D. U. S. GEOLOGICAL SURVEY The U. S. Geological Survel requires nothing of Federal Power Commission permittees or licensees except that adequate stream gaging be performed in connection with investigations and operation of F.P.C. permitted or licensed projects. In the case of the proposed project, stream gaging was accomplished by reference to the records of the U. S. Geological Survey at its gaging station located at the outlet of Cooper Lake on Cooper Creek, and by reference to other data available from the same agency on Kenai Lake and Kenai River. The present gaging station of the U. S. Geological Survey on Cooper Creek at the outlet of Cooper Lake will be rendered in- operative after the construction of the proposed dam structure at that location. It will be necessary, therefore, for the station to be relocated. Such relocation will be the responsibility of Central Alaska Power Association (and Chugach Electric ASSOCiation) under the general direction and specifications of the U. S. Geological K-4 PORT~AND • OREGON NOR T H PAC I F I ( (0 N S U L TAN T S' ANCHORAGE. A~A5KA u u u u o r ') u u Survey: and at the cost of the Central Alaska Power Association. It is also believed CAPA will be required to furnish records of diversion and lake levels after operations of the proposed project commence. This type of information, however, will be required by CAPA for" operating purposes in any evento E. OTHER AGENCIES 1. The U. S. National Park Service has no present juris- diction over any of the lands involved in the proposed project. 20 The Uo So Bureau of Land Management has no present jurisdiction over any of the lands involved in the proposed projecto 30 The Uo S. Bureau of Reclamation has no jurisdiction over the proposed project construction and operation. 40 Due to the fact that the lands encompassing the proposed project are all under control of the Federal Government, it will not be necessary to obtain any special permits from the Territorial Gov- ernment. K-5 PORTLAND. OREGON NOR T H P A ( I F I ( (0 N S U LT A N IS ANCMORAGL ALASKA u u u u u u u u o o U J APPENDIX 11111 -PROJECT COST ESTIMATES APPENDIX IIWI -ANNUAL CHARGES AND FEASIBIL ITY CONTENTS PROJECT COST ESTIMATES Ao Unit Prices - - B. Estimates -- - - Co Cost of Access - - - - - - ANNUAL CHARGES AND FEASIBll.ITY D. Annual Charges - - - - - - Eo Feasibility - - - - --- PORTLANO • OREGON NOR T H P A ( I F I ( (0 N S U l TAN T S ANCr<ORAGE. ALASKA L-l L-2 L-4 L-5 L-6 u u [j u u u u o PROJECT COST ESTIMATES A. UNIT PRICES Unit prices for construction features of the Cooper Lake Project were set up after a check on all recent contract prices in Alaska and Northwest states. There are only five major items in the project, viz: tunnel, pipe line, penstock, powerhouse and hy- draulic and electrical equipment. A group of secondary importance is roads, dam and a~liary buildings. The large machinery manu- facturers have very kindly submitted tentative designs and probable prices for turbines, generators and other equipment which largely takes the Itguess ll out of those items. The cost of steel is quite ste~ and prices used in the estimate are about two times the stateside costs. Access is always a problem on hydro-electric projects. At Cooper Lake it is hoped that roads m~ be largely a joint venture with the Forest Service. The following is a tabulation of unit costs used in pre- paring construction cost estimates. COOPER LAKE PROJECT Unit Prices for Cost Estimates Unit Unit Price Item Price Est. A. Access Facilities: Road Construction Mile $ 45,000.00 Excavation -Random CoY. 2.00 II -Rock C.Y. 5000 Embankment C.Y. 1.50 Rock & Gravel Surfacing C.Y. 4.00 Trench Excavation C.y. 10.00 Clearing Acre 500.00 B. Reservoir Preparation: Clearing Acre 500.00 C. Dam Construction: . Clearing Acre 300.00 Grubbing " 250.00 Stripping C.Y. 1.20 Remove Unsuitable Material c.y. 4.50 Rock Excavation CoY. 5.00 Impervious Compacted Fill C.Y. 4.00 Pervious Fill Sq .. Yd. 3.50 Rock Riprap c.y. 5.00 L-l PORTLANO • OREGON N 0 RT H P A ( I F I ( CON S U L TA N TS ANCMORAGE, ALASKA D U U D D D u u u u u u u D u o o • COOPER LAKE PROJECT Unit Prices for Cost Estimates, Cont. Unit Unit Price Item Price Est. D. Water Transmission: Clearing Acre $ 500.00 Excavation -Random C.Y. 2.00 II -Rock c.y. 5.00 Excavation, Trench C.y. 10.00 " Structure C.Y. 7.50 It Tunnel & Surge Tank C.Yo 100.00 Embankment from BOrTOW CoY" 2.00 Trench Backfill C .. y. 2.00 Concrete in Structures CoYo 160.00 Concrete Blocking C.Y. 100000 Concrete Anchors C.Y. 200.00 Reinforcing Steel Lb. .25 Structural Steel, Misc. Lb. .75 Welded Steel, Penstock and Conduit Lbo .40 Surge Tank Steel Lb. .40 7' Diao Concrete Pipe L.F .. 60.00 Tunnel Lining L.F. 50.00 Control Gates Ea. 6,000.00 E. Powerhouse: Excavation -Random C.Y. 2.00 II -Rock C.Y. 4,,00· II -Trench CoY. 10.00 It -Structural C.Y. 7.50 Concrete Foundation C.Y. 100.00 II Structural C.Y. 175.00 Reinforcing Steel Lbo .25 Structural Steel Lb. .30 B. ESTIMATES The summary of estimates for the several features of the project applicable to the alternate plans are tabulated below. These plans for development of the project are as discussed in Appendix "HI!, Part 1. Plans !lA-lit and i!A-2" are suggested development schemes if stetson Creek were not to be diverted at some future date o Plans "A-311 and IIA-4!1 are development schemes if Stetson Creek is to be added as the ultimate project .. L-2 FORTL.AND • OREGON NOR T H P A ( I F I ( (0 N S U l TAN T S ANCHORAGE. AL.ASKA D U o 'U o o u u u u: IU , I , , U 'U I u o D U o LJ Plans "B-l" and "B-2" are initial.Schemes "A-Jl' and "A-4" with the addition of Stetson Creek diversion works for the ultL~ate project. 1. Initial Projects. ESTIMATED COSTS -COOPER LAKE PROJECT Plan Item Lands -R/w Clearing A-l lO~,oOO IGv 2-;',000 47.5% LF $ 15,000 15,000 25,000 40.000 2 Wharves & Equipment Project l'Iaintenance Operators Qtrs. -2 Roads -F.S. from ·40:000 Cooper Landing 125~000 140,000 intake 25 2 000 Roads -Project Transmission to Sub-total $ 425,000 Dam Intake Tunnel Pipeline Surge Tank Penstock Powerhouse Powerhouse Eouipment 225,000 100,000 1,223,000 377,000 50,000 525,000 190,000 750,000 Sub-total $3,440,000 Ptarmigan Cr. Diversion --- Stetson Creek Diversion --- A-2 2-0,000 40% LF $ 15,000 15,000 25,000 40,000 40,000 125,000 140,000 25 9 000 $ 425,000 225,000 100,000 1,223,000 393,000 50,000 575,000 200,000 85 2 9700 $3,618,700 A-3 2-6,000 40% LF A-4 2-7,500 31. 7% LF $ 425,000 $ 425,000 300,000 110,000 1,223,000 393,000 56,000 575,000 200,000 852,700 300,000 110,000 1,223,000 432,000 60,000 625,000 210,000 1,017:700 $3,709,700 $3,977,700 later later " 11 Total $3,865,000 4,043,700 4,134,700 4,402,700 2% interest during construction 77,300 80,874 82,694 88,054 Sub-total ~3-,9~4~2~,~30~0~---r4~,1~2~4~,~5~74~--r4,~2~1~7~,~39~4~-r4~,4~9~0·,~75~4 10% contingencies 394,230 412 2 457 421~739 449,075 Sub-total r4-,3~3~6~,?5~30~--r4~,5~3~7~,~03~1~--4r,~6~3~9~,~13~3~-r4~,9~3~9~~~8~29 10% Engr. Supt. & O.H. 433,653 453 9 703 463,913 493,983 Total Cost $4,770,183 $4,990,734 $5,103,046 $5,433,812 Cost per }<;1;-1 installed $425 Cost/I0.v of increased capacity :$110 $110 L-3 PORTLAND. OR£GON NOR T H P A ( I F I ( ( a N S U t TAN T S ANCHORAGE. ALASKA 10 IU U u r I U u u ,/ o u U Q U 2. Ultimate Projectso ESTIMATED COSTS -COOPER LAKE PROJECT Plan Item B-1 12,000 KW 2-6 3 000 50% LF Sub-totals -direct cost from table aboveo For Plan "A-3 n For Plan IfA-4" Ptarmigan Creek Diversion Stetson Creek Diversion Total 2% during construction Sub-total 10% contingencies Sub-total 10% Engr., Supto & O.Ho Total Cost Cost per KW installed Cost /KW of increased capacity C.-COST OF ACCESS $3,709,700 30,000 185,000 $4,349,700 86,99lJ, 4,436,694 uu3,669 4,880,363 lJ,88,036 $5,368,399 $uu7 B-2 15,000 KW 2..:7,500 40% LF $3,9773 700 30,000 185,000 $4,617,700 92,354 4,710,054 lJ,71,o05 5,181,059 518,106 $5,699,165 $380 $110 The estimates include the cost of access to the siteso There is an item for two wharves and handling equipment as well as an allowance for participation with the United States Forest Service on the road from Cooper Landing. The $125,000 allowance, for participation with the U.S.F.S., is an arbitrar,r amount which reflects a liberal allowance for the benefits which would accrue to the project on the construction costs only. The allowance for wharves assumes that the first year's con- struction operation would be undertaken without use of the access road --assuming that it also would be under construction the first year. The cost of access for completing the whole project with- out the road from Cooper Landing would be less than the amount allowed for the participation on the road from Cooper Landingo L-lJ, POlm .. ANC • OREGON NOR T H P A ( I F I ( ( 0 N S U l TAN T S ANCHORAGE. ALASKA C l U u· u jU ! :u I U U u o o o o o ANNUAL CHARGES AND FEASIBJLITY D. ANNUAL CHARGES The annual charges assessable against the project power output based on the recommended project are as follows: 1. Federal Charges. Under the F.P.C. Rules of Procedure and Practice, Section 11-24, the annual charges are set forth. Administrative charge is l¢/hp/yr -16,200 hp x l¢ Fee for power production -2~¢/1~000 KWH Intake Transmission line R/w charge -$8/mi/yr Project area R/w inc. roads -75 acres x $2/A/yr Total Annual License Charges $ 162000 1,037~50 16.00 150.00 $1,365.50 The equivalent percentage of total project cost • o • 0.027% This item is very minor, however, Central Alaska Power Association is a non-profit public organization and as such may possibly be exempt from these charges. 2. Interest and Debt Amortization. Interest and Repayment: The most important costs o:f a . hydro-electric project are interest and amortization with Federal money at 2% interest annually and repayment in 35 years, a level premium requires an annual charge of . • • • • • • • • •• 4.0002% 3. Operation and Maintenance. Next in importance is the cost 6:f operation and mainten- ance. This plant is planned as an automatic station and operating personnel will be held to a minimum. This item should not exceed $4.00/~N/yr or Replacements may be added at the rate of Miscellaneous expenses Total The equivalent percentage of total project cost • • Total Annual Charges Say L-5 $ 48,ooo/yr 30,OOO/yr l2,OOO/yr $ 90,OOO/yr o 0 • • 1.8 % 5.8272% 6.0% PORTLAND. OREGON NOR T H PAC I F ICC 0 N S U l TAN T S ANCHORAGE. ALASKA u u n W o o 0' o , , '> U U u I ' 'w' W o n l.J o E. FEASIBILITY The following table summarizes the estimated construction costs, annual costs, annual power production and the cost of energy at the transmission bus at transmission voltage for each of the plans considered in the report.' COOPER LAKE PROJECT -EST1}mTED ENERGY COSTS Plan~ A~l A-2 A~3 A-4 B-1 B-2 10 5 000 KW 12,000 KW 12,000 KW 15,000 KW 12,000 iG-J 15,000 KW Item 4705% LF 40% LF 40% LF 3L 7% LF 50% LF 40% LF Estimat-ed Cost of Project $4,770,183 $4,990,734 $5,103~046 $5,433~812 $5,368,399 $5~669,165 Annual Cost at 6% 286,211 299,429 306,183 326,029 322,104 341,950 Annual Produc- tion KWlI 41,500,000 41,500,000 41,500,000 41,500,000 53,000,000 53,000,000 Overall Cost per KWH-Mills 6090 7.22 7.38 7.85 6.08 6.45 Credit for Capacity at $l/KW/mo. 120,000 144,000 144,000 180,000 144,000 180,000 Residual Charge to Energy 166,211 155~429 162,183 146~029 178~104 161,950 Residual Cost per KWH of Site -Mills 400 3075 3.91 3.52 3035 3.05 (Alternate using a capacity credit of $2/hl~/moo) Credit for Capacity at $2/KV1/mo. 240,000 288,000 288,000 360,000 288,000 360,000 Residual Charge credit credit to Energy 46,211 11,429 18,183 +33,971 34,104 +18,050 Residual Cost per K'tm at Site -Mills 1.12 00276 0.44 + 0.82 . 0.64 ~ 0.34 L-6 F'ORT!..AND , ORE:GON NOR T H P A ( I F I ( (0 N S U L TAN T 5 ANCHORAGE, A!..ASKA Q o o o o o u u u u / ) u u D o o u o The overall cost is found to be from 6.08 to 7.85 mills at the site. If a nominal credit of $l/K1v/mo. is taken for capacity value, (the so-called "demand charge ll ) the residual cost of energy drops to 3~05 to 4.00 mills and if the demand charge is raised to $2/KW/mo., the energy cost drops to 1 mill or less. Cooper Lake has many elements that favor low cost --com- plete storage, high head and short conduits o The plans proposed in this report are believed adequate and the estimates valid. With such low costs there can be no question of the project's feasibility. If Stetson Creek can be utilized, the project installation "B-2" is recommended --two units of 7,500 KW eacho Without Stetson Creek, the favored project is shown as "A-2", (two 6,000 KW units at 40% plant factor). L-7 PORT~ANO • OREGON N 0 RT H PAC IF' ( ( 0 H S U L TA NT S ANCHORAG~ ALASKA u o I' o o o {> w o u u u I~ ~ u u Q o o u- w APPENDIX "N" PROJECT DRAWINGS Plate I -Project Map II II -Climatic & Hydraulic Data II III -Hydrograph & Spillway Design Flood II IV -Cooper Creek Dam Topography II II II II II v -Cooper Creek Dam Geology VI -Cooper Creek Dam -Logs of Subsurface Exploration VII -Tunnel, Conduit & Powerhouse Area Geology VIII -Cooper Creek Dam IX -Tunnel and Penstock Profile Intake Structure " X -Surge. Tank and Pipe Details II " XI -Powerhouse Design Layout XII -Electrical One Line Diagram PORTLAND. OREGON NOR T H PA ( I F I ( (0 N S U L TAN T S ANCHORAGE. AUSKA ~' • DRAINAGe: BASIN PLAN , . ---------------_ .. -.----------_ . PROJECT YAP IG .. L ....... . . ••• lel' ----------_ 11' . .-.' --?c;;..r£~""" TYPICAL SECTION PROJECT ROAD "C:"LtFi··r~o- ~. ,,',' _.,foJH 4on/h/1«1r ;:':":Y" /'taM pi«~ ,Jrornt til I'JPf! ~nlr#I"JC~ i l .. "I' kit ! t LA VOUT AT PowER HOUS£ .CA"'"1"0 3100' VICINITY NAP 10All:*, .. -UU'l .CA". "' .. u. •• • •• n -M. DRt;.198·2 PL A T t: I . . -.... -.-.... ------.-.-------.--------___ -----___ -_---..-....,_!-"fI.,.....II!IIIIMI ...... ~-............... - , 0 CJ CJ --r ) 't=J 't=; 'c c~"--c= r::= c:: 1,"'----~~--=====-=-==~---" ! " J ! 1 .. Ii rrr ! II tiH r;:E: "., I .$zWAR" .. /'hcord I'or 46 ye.;r.$ J.t Ih!cord Incomplt!/t! lor fhas~ YlUr!J I COON.R LANDIN6' Rt:c:.ord fOr 1 ye4rs ~ ~ .... it ,. .. ..,. -' ... n o .... WAT'.q Yt'AR I!N"JN(I S,,~r8MIJIIf ~o PAlcIPfrATION.AT S/!WARDAN/) COOPER lANDINO 1~40 'no ..J 11.00 "i ~ ~ 11&0 0 II) 't ~ IlGO 0 ;: ~ ... .;; 1120 COOPER LAKE RESERVOIR ARI!A IN ACRZS .-.-1000 osao ., I:l ~ .q; "I :, 0 ~ ~ ~ 0 . :t ~ C .... veA -F_"'Coo~rC..t,fJl"';.r ~ mouII>.u1u dlvtrrtin9.N/J"h.t. fftJm C~r ~ Hvv ~r;'oun CuRve !1~rbw;,CDoperCk~ Qlmilfom I'n(}t)lhdl'lq divlfrf,"'9 0111 f~llil:':!2;:ct!Jc~ up 10 ~c fs 100 ,., C""V~ C . 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L~ - .. ~- .------.. -----~---.. -.--.-------'--------------..... -----__:---------______ --__ ......,.,J -1 -----------------------~-------------------------------c=----c .JECTION :4-A' PLAN tJF IJAMSIT§ killS: I inch. /OO.I"HT S~JJ.. IN 'Nr A:)() 0 A:IO'otJJOO.oiItDSDO I t;#oI.O(;IC (}tOSS S«TION "" AXIS OJ'OAM -------------------.--~ ------------ -...:=,.- ."("."D .. COO "OE~f. LAIC. 'IIOller GTTECREEH DAM OLOGY ---... _-- -"'_J..~ '0 __ -- 0"", 198-6 PL ATE V. CJ ____________ :_ .... 4""' ___ .:... _______ ~-.----------I .• ___________ _ -'a=:= ... t=J - c Cl (--J Pl.AN FROM INTAKE TO POWERHOUSE SeAL,!': !tAl. -1000,r. SCAL~ IN rr,r _ fH1tOD.iQIoo I4(JtQ "-'''-'-~~-~'' -,..-----,.------- Tot81 .,1 Hole liIlHl)q>Ih JU' Holt! 414P..s. 74'W. Loc"t: ""'*t ..... Sb..'J>,o.l4I.1.OZ. L"" .. t_,7U.'ne(LH>!SIdO'l7.121SZ. HmtJ Slarf:4'!2~:U FiniS.hIJ-14~'.S4 rlirN! SI/rl:!f.,.u /i""o$": '~/J·:U £f('JII"lions: Grottnd~"EL,u24 llev.l/on~" &-ound Svr/Jett Ellf}l!l' R«tSurrJlce ~I.IITS7 -~- DRGI98-8 PLATE 1lll . ---------------~--.... --........ ~ .. ---.----------------~------------------~----------------------------~~----. ----_._----- .; -. :~ . f f ,. & ~~ .~ re l $"( . ,.-----------.. -.. " • II • t • • I 7 • , I l " J ;: ~ " Jt#It"Jd4t#,t ,sIUAA" _ DOO "Ii 4' • .., '.1M •• .. ~ , • ~~~_-_~_~_~_-_+_-__ ~ __ ~_t_~-h~ ~ ~ • ~ • ~ U ~ 4 ~ ,,» ~ ,s1f:JlU(;l' 1M JQ)Q.lS I .5RUIVAY /)GSICN .ct.()()I) .Q:vhM:; ClIRV~S , "~d~~.1 . J .q.w"",; 'flU.." E~.))JI2 ~I't fts-pnnood N~ , ~~tl---~-- I ."-+-H-HI-+- $ :'HH-I-++-f- , :'HH-++-+-v-t- ~: , 'I"" § , " II , ... . ~ 1194 I 4 ~ , I ~ 110. ~ " ., • R .. , 'Ii • I • , • l ~ 104tlJtIOiJOAJtfJ,/Jt) TIME .~ ttoUR.3 !/OUIM£ "" SPILlVAY b£.JItW ,&to(}() -----I " CINtaAL ALAS .. " ,own "$:SOC,ATtON fG(,TION ~-A' TIIIlOUt;ll bAM • :,~.". ,)i;,. ... ~.,. t-_____ ._N.,.C_HO_R_._G..:f:.., _ • ..: .. ...:':.. • ...:. ____ -1 -4ii...f.~ COO," tAICI ,1/011eT kal,: ~ .. * zo ,.,~ ~ d __ "_H • OM) II(J .. ,,,'~ COOPER CR££K DAM ~::: !:;: "" :,<[.1== '0 __ -- DRG.198-!J PLATE m ~, ---------------'"-~~--- '. ,lIen"" A-A .c ..... :.· ... 4 TUNNEL & PENSTOCK PROfiLE V"A"fCAL OCALa.-".100" ..oaU:ONTAL SCALa' 1-. lC'IO' '. e steTtON 6·6 .eALc,.·.r~ I!ImKJ 7'/'N1.d H(III"" • .IhH ~ ~I,IIJ$ ., SI!CTION 0'" ~ PLAN & DETAIL OF INTAKE STRUCTURE 6C A" £ -,". to'-o-- .---- - ~~-~--+--~----I---- i -~-'I CJ • 5[CTIOH &-8 TYPICAL ANCHOR A • SECTION ON "'- fO. STEEL PIPE r-d'iU Ci,.,,,lk i ,<,-..... A.i!!.. /.int!Jd 7un/')f!/ TYPICAL TUNNEL PORTAL .. sn, PIP~ CONNECTION _co'II"-I'- TANK COVER OETAIL &C"Le.:I··r~O· SECTION A-A SURGE TANK DETAILS ~cALl ,-.. 1'-0" . ,. r---------------l -S~,./o", tL -"Pa7Wri-;;;;¥~~ ------- secTlo .. C-C PTARMIGAN r : CREEK CROSSING" CLEAN-OUT SCAL"I ,-. 1'-0· 1- -""::::"-, CU"UAl ALASK" POWUl A\SOCIATIOH ANCHOIAG" Al,AUA ... _-- lQf<'t_t_ -~--= 0140.198'" PLATE X -------------------------------------------------------- y " " :1 :! " ii Ii " :: I' .. " " I: " " :1 II " ji i! ii n I' 'I " II 11 I, 'I :1 I' I' ii i! :: I: II p Ii II q :1 q :: :: 01 n " II I: Ii H II 'I II " i: II I' II I' n Jj II d' "" II " II ~AOO' 't~nl ;.l !I Ii .. I ROOF PLAN ~CAL.I"·r·o" '-0' TOIL"" IIIII I I I O"ICIl 5wnCH&oARD ROOM .' MEZZANINE FLOOR PLAN ScALI:\".r-o· G~'-O' cO ,-","\, , , 1'''' c A GENERATOR ROOM -fLOOR PLAN ~C"'LI'\''''''O' SECTION A-A ScALI't;-1'·0"' SECTION &.& ~CAU·'··I·-o" SECTION C-C 'S.cALI,\-.I"o· --- KENAI , .... ;;;1- LAKE POWER HOUSE SITE r cun .... l ALASkA POW(A ASSOCIATION "'NCHO.ACt:, Al·ASk ... DRG.198-12 PLA TE 1lI ·1 EJ n4l~1 ~MChU' Mt; :J#IIoIiNnwlo· ~hcslrr'l Ni7fn1I6nd -.".~ - ------------------------------------~, ---------------------------------, TELEMErERIN6 rlJNCTION.!I S~RY''''oRY ... h...WTS <<<Il Gcn",.6for .. .Jl:: ~ LOI:kO<J1 Rrlay. MiG:J G41t: Limil ! GJ)If: Pos';,fo,r. it;;;:, I·t:~ Gftne,..larA.8C "'f\t?unci .. lor fJ./:l~';:;/j/op ~fU<!nctJ F~V"f". Mf5C(LL .... N(Otl!J Lir'/(! Volls ; 8v-s Voll. IIsKvaC/J·, G9KVoca: Locl",.,1 R"I8y,IIliT Ff:(fd~r AC~s- 51" s"rv. 81r,; C.,.rlittr "~ilurt! A~"'t:~~~ I 8GG2 ! LeGEND 2 ~ n.. IMloy A"lqy '" Malllttl" (Cwb-oI' Alii"), II Otftt,.~d -S.Jilch IJ ~##'" Swilr:/t. Opow Ii' 'S.II .,... 'I"Hd I., lJndil"slHilti .... ik..+ ~ ~.til'l 20 41'111'. C"",I'f"oI '1 "''''''~NQnit1/ lJiJhv/« /mp~"~ .. .." 2$ Au~/ic ~~IV JC)~""I.IbI-""'I"'II :: ~:::;:;t"r~rol"'" Jlll/ay 4~ O/l'flf"IfIOII~ .II./~ ~6 PhtI.iI ~o/Ql!lCtt /'III/O'y ~~ ~:.~= ~:",.o~ Ihtl,. 'I <;IIIN,.,."n". Air ('iFnHl'lfrf'ohr 111111 D;""_/~ R.rA!J- :. r.~~'~.2'~" ~ lilY !/I,.av",. 11>,,-~fo\1lmy,......,. .... .. II,-",Ial· 114VI<i i1;HI'YI'H " 11,101 ....... , Alrl..,.. A>r linw , ... 1; ""'Y 46 lockoul .Q,..4rY tI7I; ~ OiHlt"",Ntd Alrltlil 477 TnwuI"_,. DlI'~rvr;i4'II#"'" : ~1az(l~~~r., ITN ,U __ • lid,!!' _I.JU~ ~: ~: 4. ~at.:d4Y: ~: ~_y. 4- 211 ~r. Utd<t""",. Kc"!r' 1"",'YfV'Oi! -'<jDP;' IN Yt>,"'vtt ntl..,.,lop"""~ nt,/(>",", tptrtdion on de#lld linft (M~ SIX. 4f<X. 'iI'S. Ann. Sl-:. .1/1. S2-N2. I-:-:..r":, t~_ CMr~r";"Jb\_ ! .11-1. L_ cil p,.,,,,,,ure • A Am",.l.,. If YoIl'ln«trf"" 2. L..: .. I Conko/ .lM<kh. I 6'6T I Qluilled ~: ~: 81TX. I!iHdlSl-2. .1/9. A~ Supuv'-'''''.Y S2rS;-1 ! lI' 11'#11",."",. nil yq,.",.Itr". llYN ltI'anhotJ!l'",./W,.. r~ T"+~rm41 ~....".w AS AM"""lttr .Jr.N"1c"A ~~Nw<.,.... ..{i£c /ltlitcOtf"dttr tuns AIr_III €'on;,.,IM<1' SIt'""" ..... :..-" PIUi _/~f t;tt"""",.,. ~~ ~;::;~k;:;;nlhl IMwt. fA. rran.millrr 14 ~«.i",r :II' ..JUr9" P,..,led; ... E9u{Dm#nl I... l.i9Alnir'l .Irnt.tv C'« ('ross ~I 1'bm,......,1or TRr T,.",,.IOrm,,,, IJrop a..,...- <"(' ('-,in.f ~iibr NOTES l All ""IwmIitII ~"3 IV .. '" -" unA!s. orn.rW'lMf "ACHi+"7, ~C=I'Z.t%::f;::1: aI' tA>,~ Atll .oj, Ao .-.. .1 M!lul,. .. , ",,,,,,iIY .oj, &t p"_i_ ,T uro ""- ~tl"Ctl reiICl.nctt at" m8clt1n6 purch8S(k/ 9'WJs :'::'~~~:t;~tltlr 11>...., ~tI $t!ner 4lor -------------_._-----_._--_._--. .-. __ .--. ----..-' • ----------- L • C" ... ,,. ......... 1' ................. , .. I C I I" I I L D --t=] G U.t., 0' ALASItA CHUGACH IU;CTAIC AS50C."TIQt.41\1C. .MeNO_AGI. ALA'." COOPER lAKE PROJECT SfRYICE AREA C. TRANSMISSION LINU ...... -.. ~................ .. ... -................. .----. .... -----"----------------"-----"""--"------~-----""--" ""-------" --£-1 • L .••• &I ---------------------------- STETSON CREEK . ~~-------,-------------___ /~- ·---------Jt c 1$0 -' -' SECTION 8-8 PLAN . 4'1.' C#II """ 5h.1ko Gilt. ",Ib_ttling_ SECTION C-C SECTION A-A _.tliH"_ «JtItp«,.d imP'YiQn Ilft'INnai NQ $..ot. TYPICAL CANAL SECTION IN EARrH NOrE$.-",' __ pI an "'oinlt,-I1'rIIDmI tI/ttng """" __ ,,,,. I. tI,I.,," Prorin J #Pill."", "I, •• ,.d ItIctllitNr, Ir:I mll'-ue."i"tI 1I11W' . ",lIlIin, l'tIm tllu"i"(1 rf/lt .. tt/I 01 itII"n~H dnilNl,. . . TYPICAL ROAD SECTION fMtJI_ roed IJdpUn! III ttl"'" ,.".", , .. ,iIM. NOTES. .::51 J. F"Id illn6liglllitJntl lihlilMlIrI '"DltltfJi"(J/JC# IJ, 01, and"" ltJol. I.r_"""" "'ton ''''''' "'" Us. Gottlo9itltI5.,,0, $.11_. ,.".,""'" tV IhiJ "N()IfI /HId Dnd ,,6., " 'J'pkal ut.pf lor I/fH'JU I«tII "'tlfI' ."'''' 1110,. DT In, utISir1II. . J.rM pimmit" _,1, '''' 1M tItIm ItJltl i:ttnttl tin _/)lima,. MIT- Et_it ""tI, '" "'" dtlM1, ";0110 mttdtl ttlIo, '"1d ..,,..,, anti ,.1l/o9k in •• lligaliDnI IIttn Molt clJJtlpNllH. «r. #1# /lUll' ". tltonftld /(I II 1m"" a,dI (If' ma'M" ,lTilClII,. ftJ ,NfIt. nt. ~t,..l. ttIIJIlItIlllHl Clift f 10 10 Stal. in 'till .0 C"UGACH fUCTAIC AUOCIATtON.IHC. ANCHORACE. ALASKA coo, .. uli. nOl.er STETSON CREEK DAM AND CANAL (PRELIMINARY) tIOfl't. ~'II$ ¢OQVl,'un ... N. .. ltIII..... '0..,1001 SECTION E-E TYPICAL CANAL ${'CrlON IN ROCK DRa.19IH5PLATE m