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HomeMy WebLinkAboutChenaga Hydro-Electric Feasibility Study 1992CHENEGA HYDRO-ELECTRIC FEASIBILITY STUDY PREPARED FOR ALASKA ENERGY AUTHORITY P.O. BOX 190869 ANCHORAGE, AK 99519 BY PHUKAN CONSULTING ENGINEERS, INC. 203 W. 15th AVE., SUITE 104 ANCHORAGE, AK 99501 OCTOBER 20, 1992 (H92466) CHENEGA BAY HYDRO-ELECTRIC STUDY Prepared for ALASKA ENERGY AUTHORITY P.O. Box 190869 Anchorage, AK 99519 PHUKAN CONSULTING ENGINEERS AND ASSOCIATES, INC. 203 W. 15th Avenue, Suite 104 Anchorage, Alaska 99501 October, 1992 (W .0. 92466) PHUKAN CONSULTING ENGINEERS AND ASSOCIATES, INC. CHENEGA BAY HYDRO-ELECTRIC STUDY TABLE OF CONTENTS Page 1.0 INTRODUCTION 1 2.0 BACKGROUND INFORMATION OF CRAB BAY DAM #4 2 2.1 Location 2.2 Geology, Seismicity and Topography 2.3 Climate and Hydrology 2.4 Water System Construction History and Details 2.5 Electrical System Construction History and Details 3.0 FIELD INSPECTION 5 POWER GENERATION POTENTIAL 5.0 CONCLUSIONS AND RECOMMENDATIONS 8 6.0 REFERENCES 9 Figure #1 Location and Key Map Figure #2 Topography of the Site Figure #3 Dam Plan and Evaluation (from U.S. Department of Health and Human Resources Photo Plate Numbers 1 -19 4.0 EVALUATION FOR GENERATION OF HYDRO-ELECTRIC 6 PHUKAN CONSULTING ENGINEERS AND ASSOCIATES, INC. CHENEGA BAY HYDRO-ELECTRIC STUDY Phukan Consulting Engineers and Associates, Inc. (pC A) was hired by the Alaska Energy Authority (AEA) to perform a hydro-electric feasibility study at the water supply dam (known as Crab Bay Dam #4) located at the village of Chenega. The scope of the work consists of: a) A meeting with the project manager, ABA to gather all pertinent information and to finalize the data for the field investigation. b) A field inspection of the existing water supply dam (Crab Bay Dam #4) and other potential sites and record all pertinent information. c) A technical report incorporating all field findings and conclusions regarding the potential source for a hydro-electric project. PIIUKAN CONSULTING ENGINEERS AND ASSOCIATES, INC. 2.1 Location -- CHENEGA BAY HYDRO-ELECTRIC STUDY The dam is located on the east side of Evans Island in Prince William Sound, approximately 2,500 feet north of the new Chenega village and 2,500 feet west of Crab Bay (Figure 1). The coordinates of the dam are approximately 6004' N latitude and 14801' W longitude. 2.2 Geology, Seismicity and Topography Evans Island is located within the Kenai Mountains Fore Arc Ridge, which is typified by folded, faulted and uplifted sedimentary and basaltic rock exposures (ref. Leet et. al., 1978). Bedrock in the vicinity of the dam consists of thinly bedded slate on shale. The shale is typically gray, moderately hard, brittle, and dips at 50 degrees or more to the east with bedding planes parallel to the creek. Surface soils are primarily peat (up to four feet deep) overlying bedrock. At least one source of granular soils has been identified in the area of the village. Evans Island is located in Seismic Zone 4 and along with most of the south coast of Alaska, is one of the most seismically active regions in the world (ref. Beikman, 1974, and Espino, 1984). The drainage basin is about 0.37 square miles, has a southeast exposure, and rises from elevation 244 at the dam to a maximum peak elevation of 1700 feet. The existing reservoir lies in a narrow rock gorge and has a surface area of about 600 square feet at elevation 250 (photo plate numbers 3 to 12). A topographic description of the area is presented in Figure 2. The creek below the dam flows through a steeply cut rock gorge, then over a ten feet high log crib dam, through the village, and into Sawmill Bay 0.6 miles from the dam. 2 PHUKAN CONSULTING ENGINEERS AND ASSOCIATES, INC. 2.3 Climate and Hydrology CHENEGA BAY HYDRO-ELECTRIC STUDY The mean annual precipitation for the area is 160 inches per year. The mean annual temperature is 40 degrees Fahrenheit (ref. U.S. Department of Comm~rce, Weather Bureau, 1963). The mean annual flow rate is estimated at 3.2 CFS. The mean minimum and maximum month flow rates are estimated at 1.0 and 6.2 CFS. For estimating purposes, the following monthly stream flows are assumed: • 2 months @ 0.9 CFS • 8 months @ 3.1 CFS • 2 months @ 5.9 CFS 2.4 Water System Construction History and Details The existing dam is part of a system that was constructed in 1984 by the U.S. Public Health Service to provide potable water to the new Chenega village. The dam is constructed of reinforced concrete and has a spillway crest of elevation 248. The dam was inspected in 1986 and found to be in excellent condition (ref. Shannon and Wilson, 1986). A 4" xl, 150 lineal foot HDPE insulated transmission line extends from the dam to a water treatment plant (photo plates numbers 12 to 16). At the treatment plant, the water passes through a 48" diameter pressure filter, and is treated with chlorine and fluoride. The water then enters a 6" transmission main that ties a 50,000 gallon wood stave storage tank (photo plate no. 17) to the village distribution system. The water surface elevation in the tank varies from elevation 150 to 165. 2.S Electrical System Construction History and Details The existing electrical grid was constructed in 1984. The generating system presently includes two 480 V three phase diesel generators with 65 KW and 85 KW rated outputs, respectively. According to our discussion with Mr. Tom Brown of Tab Electric, the original construction contractor, the primary 3 PHUKAN CONSULTING ENGINEERS AND ASSOCIATES, INC. CHENEGA BAY HYDRO-ELECTRIC STUDY distribution grid is in a 12,47017,200 volt three phase underground system. 120/240 volt single phase service to homes and the water treatment plant is supplied by several pad mounted 7,200 volt transformers located throughout the village. 120/208 volt three phase service is supplied to the school. 4 PHUKAN CONSULTING ENGINEERS AND ASSOCIATES, INC. CHENEGA BAY HYDRO-ELECTRIC STUDY A meeting was held between Don Ruef of AEA and Arvind Phukan of PCA before the field inspection. Mr. Ruef provided the necessary background information on the project, which was useful to accomplish the field observations .-- A field inspection of the water supply dam site was performed by Dr. Arvind Phukan, P.E., of Phukan Consulting Engineers and Associates on July 9, 1992. Photo plate numbers 1 to 19 illustrate the site conditions near the dam, the dam structure, the intake water pipeline system, water storage tank and the water treatment building. During the site visit, water was flowing over the dam through the spillway (photo plates numbers 7 to 9). The existing concrete dam (described earlier) is found to be in good condition. At the downstream area away from the dam, some surface slope erosions were observed near the water pipeline which was tied with wire ropes (photo plate no. 16). It appears that some of the existing water pipeline sections near bends need repair. During the field inspections, discussions were held with Mr. Steve Ward, the maintenance operator at Chenega village. He provided useful information regarding the water supply system at the village. No other sites near the village of Chenega are viable sources for the generation of hydro-electric power. PHUKAN CONSULTING ENGINEERS AND ASSOCIATES, INC. CHENEGA BAY HYDRO-ELECTRIC STUDY Two separate alternatives were considered for adding hydro-electric generating capacity at Chenega Bay. Both included using the existing dam with minimal modifications. -- Alternative #1 consisted of adding a turbine/generator set-up near the existing water treatment plant; see Figures 4 and 6. A 10" HDPE penstock would be added in parallel to the approximately 2,000 feet long existing 4" transmission main. The turbine would be a Pelton wheel-type, and discharge from the turbine would flow via an open channel to an existing drainage ditch in the area. The turbine would be installed at about elevation 70, and the generator would have a peak: capacity of 38 KW. Alternative #2 consisted of adding a turbine/generator set-up near tidewater. A 12" HDPE penstock would be added in parallel to the existing 4 II transmission main from the dam to the water treatment plant, and as required thereafter; see Figures 5 and 6. The total length of the new penstock would be about 4,000 feet. The turbine would be a Pelton wheel-type, and discharge would flow via open channel to an existing creek or directly to tidewater. The turbine would be at about elevation 21, and the generator would have a peak: capacity of 50 KW. For both alternatives, hydro-electric power generation was estimated for present conditions, and for design conditions, at which time potable water demand would substantially reduce hydro-electric generating potential. Tables 4-1 and 4-2 summarize present design conditions for Alternatives #1 and #2. Based on the results of Table 4-1, Alternative # 1 has a calculated annual power production of 176,000 KW -HR/year under present conditions (assuming 20 % down time), and 127,000 KW-HR/year under design conditions (assuming 30% down time). Assuming a design period of 20 years and a linear reduction of power output over the design period, total power generation is estimated at 3,030,000 KW-HR. Costs for Alternative #1 are summarized in Table 4-3. These costs are based on PHUKAN CONSULTING ENGINEERS AND ASSOCIATES, INC. CHENEGA BAY HYDRO-ELECTRIC STUDY the assumption that a cleared site with existing access is available near the water treatment plant at a "zero" acquisition cost. Power would be generated at 480 volt three phase and "stepped up" to 12,470 volt three phase for compatibility with the existing grid. Based on the results of Table 4-2 and similar assumptions to those described above, Alternative #2 has the following calculated power productions: Present Conditions: 229,000 KW-HR/year Design Conditions: 167,000 KW-HR/year Total Production: 3,960,000 KW-HR Costs for Alternative #2 are summarized in Table 4-4. These costs are based on the following assumptions: a suitable site is available near tidewater, and with 1,000 feet at the existing Chenega Bay 12,47017,200 volt three phase power grid, at a "zero" acquisition cost. As with Alternative #1, power would be generated at 480 volt three phase and "stepped up" to 12,470 volt three phase. Consideration was given to analyzing an alternative for raising the dam crest to expand hydro-electric potential by increasing reservoir size and increasing available head. However, because of the steep-side configuration of reservoir, reservoir capacity would not be increased significantly without a large increase in dam height. Correspondingly, a large increase in dam height would require a large capital investment, which in our engineering judgement would be prohibitively expensive given the limited scope of the project. 7 PHUKAN CONSULTING ENGINEERS AND ASSOCIATES, INC. CHENEGA BAY HYDRO-ELECTRIC STUDY i) Beikman, H.M., 1974, "Preliminary Geologic Map of the Southeast Quadrant of Alaska". U.S.G.S. Misc. Field Studies, Map MF 616, scale 1: I,OOO,OQO ii) Beikman, H.M., Holloway, C.D., and MacKevett, E.M., Jr., 1977, "Generalized Geologic Map of the Eastern Part of Southern Alaska", U. S. G . S . Open-File Report 77-169, scale 1: 1 ,000,000 iii) Espinosa, A.F., 1984, "Seismicity of Alaska and the Aleutian Islands", 1960-83: U.S.G.S. Open-File Report 84-376, scale 1: 12,500,000 iv) Leet, D.L., Judson, S., and Kauffman, M.E., 1978, "Seismicity of Alaska and Aleutian Islands: in Physical Geology": Prentice-Hall, Inc., pp. 147-153 v) Moffit, F .H., 1954, "Geology of the Prince William Sound Region, Alaska", U.S.G.S. Bulletin 989-E vi) Shannon and Wilson, 1986, "Crab Bay Dam #4, Evans Island, Alaska" , Periodic Safety Inspection Report, Alaska Dam Safety Program vii) U.S. Department of Commerce, Weather Bureau, 1963, "Probable Maximum Precipitation and Rainfall Frequency Data for Alaska": TP #47 9 Present Conditions " II " II Design Conditions " II " " Table 4-1 HYDRO-ELECTRIC GENERATION ALTERNATIVE 1 STREAM FLOW 2 mo. @ 0.9 CFS 8 mo. @ 3.1 CFS 2 mo. @ 6.1 CFS 2 mo. @ 0.9 CFS 8 mo. @ 3.1 CFS 2 mo. @ 6.1 CFS POTABLE WATER CONS. 0.5 CFS 0.5 CFS 0.5 CFS 1.1 CFS 1.1 CFS 1.1 CFS NET FLOW & HEAD FOR HYDRO 2 mo. @ 0.4 CFS & 177 FT. 8 mo. @ 2.6 CFS & 158 FT. 2 mo. @ 5.6 CFS & 95 FT. None Available : 8 mo. @ 2.0 CFS & 166 FT. 2 mo. @ 5.0 CFS & 111 FT. KW OUTPUT 5 28 36 o 22 38 Present Conditions " " " " Design Conditions " " " " Table 4-2 HYDRO-ELECTRIC GENERATION ALTERNATIVE 2 STREAM FLOW 2 mo. @ 0.9 CFS 8 mo. @ 3.1 CFS 2 mo. @ 6.1 CFS 2 mo. @ 0.9 CFS 8 mo. @ 3.1 CFS 2 mo. @ 6.1 CFS POTABLE WATER CONS. 0.5 CFS 0.5 CFS 0.5 CFS 1.1 CFS 1.1 CFS 1.1 CFS NET FLOW & HEAD FOR HYDRO 2 mo. @ 0.4 CFS & 226 FT. 8 mo. @ 2.6 CFS & 203 FT. 2 mo. @ 5.6 CFS & 128 FT. None Available 8 mo. @ 2.0 CFS & 212 FT. 2 mo. @ 5.0 CFS & 147 FT. KW OUTPUT 6 36 49 o 29 50 A. CAPITAL COSTS Table 4-3 COST ESTIMATE. ALTERNATIVE 1 (1992 Dollars) COST 1. Dam Modifications $ 18,250 2. New Penstock 163,000 3. Power House and Equipment • Site Work 17,000 • Building, Furnish and Install 20,000 • Turbine, Furnish and Install 18,100 • Misc. Piping, Furnish and Install 4,600 4. Electrical • Generator and Switchgear, Furnish and Install 31,350 • Step-Up Transformer and Intertie, Furnish and Install 26,200 TOTAL DIRECT CONSTRUCTION COST $298,500 TOTAL INDIRECT CONST. COST (20%) 59,700 TOTAL CONSTRUCTION COST $358,200 CONTINGENCY (25%) 89,550 Subtotal $447,750 ENGINEERING AND ADMINISTRATIVE (15%) 67,160 Subtotal $514,910 INTEREST DURING CONSTRUCTION (12%/YR) 3,000 TOTAL PROJECT COST $517,910 B. C. ANNUAL COSTS • Annuity @ 7% • Labor • Misc: @ 2% TOTAL ANNUAL COST UNIT COSTS COST/KW-HR COST/KW INSTALLED CAPACITY $ 48,890 32,760 10,360 $92,010 $0.61 $ 13,600 A. .. 1 J B. C. Table 4-4 COST ESTIMATE, ALTERNATIVE 2 (1992 Dollars) CAPITAL COSTS ITEM 1. Dam Modifications 2. New Penstock 3. Power House and Equipment • Site Work • Building, Furnish and Install • Turbine, Furnish and Install • Misc. Piping, Furnish and Install 4. Electrical • Generator and Switchgear, Furnish and Install COST $ 29,000 369,000 18,000 20,000 18,100 4,600 32,800 • Step-Up Transformer and Intertie, Furnish and Install 26.200 TOTAL DIRECT CONSTRUCTION COST $508,700 TOTAL INDIRECT CONST. COST (20%) 1Q1.74Q TOTAL CONSTRUCTION COST $610,440 CONTINGENCY (25%) 152.210 Subtotal $763,050 ENGINEERING AND ADMINISTRATIVE (15%) 114.46Q Subtotal $877,510 INTEREST DURING CONSTRUCTION (12%/YR) 5,000 TOTAL PROJECT COST ANNUAL COSTS • Annuity@ 7% $ 83,310 • Labor 32,760 • Mise: @ 2% 17.650 TOTAL ANNUAL COST UNIT COSTS COST/KW-HR COST/KW INSTALLED CAPACITY $882,510 $133,720 $0.68 $ 17,650 II IL-- • --- ALASKA FIGURE 1: FAIRBANKS • PACIFiC OCEAN TERkn'ORY KEY MAP CHENEGA BAY I OJ", --.--~------------,---------. - : .. ;. . , J . . ..- " N..:.v Y..:Jtl bl .. lllej:.. • • L . .. " , ' ... , .. : .... :f .. -: i'~ ,": " .~: :'.' ...... ~ ~l r-----------------------______________________ ~ _________ ·V~_·_J_ FIGURE 2: TOPOGRAPHIC }.tIAP i CHENEGA BAY w':;'~;J.------,--,--.... C'-:-,.--T (I)' , HI2;!Julti~l1n~}~~N '. , 203 W 15th., Suite 104, Anchornge, Ak .• 99501 . .. Tete: 907 272-7111 Ftlx~7J ~77-J J 77 .1 L ___ .. _______ _ I .. ,,... '·t"I".ee I"r .. m "01" _ce",,.. <"""CO '''_ •• ".r-InATC" Q ·;,..,-;:;::;l-;:~~~::_A , ... v. n::J",.,.I.IU I \.ov .•• '·. " ...... .,uu VI"--I .. h.,,"",-L. I -t IVIIL..C J ..... " , .... u-~ I -::..··~L~4_' -~_'~'_'.'-_J 1 1 ; 'J i j SAWMILL BAY 1\ I~ )r /) \~ \ \ I ( \ \ I \ \ \, , ' \ I ( \ '( ~ " l \' \\ \ \ \ \ I I I I I I / ; /) / ! // (~ , , I I NOTES POSSIBLE LOCATION 16'x24' POWERHOUSE SEE FIGURE 6 AND NOTE 2. POSSIBLE ROUTE, ____ 1O"¢ PENSTOCK 1. ROAD SYSTEM SHOWN. BUILDINGS NOT SHOWN. 2. TURBINE DISCHARGE TO EXISTING DRAINAGE DITCH. EXISTING CRAB BAY DAM #4 J PHUKAN CONSULTING ENGINEERS & ASSOCIATES, INC. CHENEGA BAY HYDROELECTRIC FEASIBILITY STUDY ALTERNATIVE 1 Civil Geotechnical • Surveying • Environmental Telephone: (907)272-7111 Fax: (907)272-3177 203 West 15th Avenue Suite 104 Anchorage, AK 99501 DRAWN MBP GRID SCALE 1"=300' DATE 1-7-93 F.B. PG. W.O. H92466 COMP FILE NO. 466SITE FILE DRAWER NO. FIGURE 4 I I I 'II I~ I! · .. SA WAlILL BA Y ( \ '( I i. \. ~\\ I I I I I I / / ) // I I // /(; I I r-, );/) I; /; II II II II -:::.-~ ---~-:::-~ r "-~~'--...-.~ EXISTING 20' x 20' WATER PLANT ----'/ / PHUKAN CONSULTING ENGINEERS & ASSOCIATES, INC. Civil Geotechnical. Surveying • Environmental Telephone: (907)272-7111 Fax: (907)272-3177 203 West 15th Avenue Suite 104 Anchorage, AK 99501 / POSSIBLE ROUTE i 2"0 PENSTOCK NOTE r EXISTING CRAB BAY DAM #4 -"',.,.....'--- 1. ROAD SYSTEM SHOWN. BUILDINGS NOT SHOWN. CHENEGA BAY HYDROELECTRIC FEASIBILITY STUDY ALTERNATIVE 2 DRAWN MBP GRID SCALE 1"=300' DATE 1-"7-93 F.B. PG. W.O. H92466 COMP FILE NO. 466SITE2 FILE DRAWER NO. FIGURE 5 I :· i " " j II 1 24' · . 16' --~ .. -~--.------~ ~ PREFAB METAL BUILDING ~ ON CONCRETE SLAB --~----------~-------~ MISC. ELECTRICAL ELECTRICAL ROOM SWITCHGEAR, TRANSFORMERS, ETC. 8' OVERHEAD DOOR PELTON WHEEL TURBINE GENERA TOR (OVER SUMP) MECHANICAL ROOM u ~-10" OR 12" PENSTOCK (HOPE ARCTIC PIPE) FIGURE 6 BURIED 24"¢ CMP TURBINE DISCHARGE TURBINE DISCHARGE DRAINAGE DITCH CHENEGA BAY HYDROELECTRIC FEASIBILTY STUDY PROPOSED POWERHOUSE PHUKAN CONSULTING ENGINEERS & ASSOCIATES, INC. _ Civil • Geotechnical • Surveying. Environmental 203 W 15th., Suite 104, Anchorage, Ak., 99501 Tete: (907) 272-7111 Fax: (907) 277-3177 1"'0 9'JA.-::.;--rr:OUP 1'1'" A'-::'-::OTL "'('A'" "'Teo rlATE1!7/g"'l Ay M8D t ~.~ . . L""rVV ....... ¥" ~ I \t...>.--rvv I ..... v '-'-,., l.,j .... I I # I '-' ..... II! PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] Chenega Hydro-Electric Feasibility Study October 12, 1992 PHOTO PLATE NO.1: Site of Chenega Bay water supply dam. PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] PHOTO PLATE NO.2: Stairways leading to the dam. Chenega Hydro-Electric Feasibility Study October 12, 1992 PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] PHOTO PLATE NO.3: Upstream view (looking from top). Chenega Hydro-Electric Feasibility Study October 12, 1992 PHUKAN Consulting Engineers &. Associates, Inc. [W.O. H92466) ~:.. .. ,' ... _ ~L_\',' ", ,. _"_.:_' PHOTO PLATE NO.4: View of upstream reservoir area. Chenega Hydro-Electric Feasibility Study October 12, 1992 PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] Chenega Hydro-Electric Feasibility Study October 12, 1992 PHOTO PLATE NO.5: View of left abutment (looking from top). PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] PHOTO PLATE NO.8: Upstream view of the dam. Chenega Hydro-Electric Feasibility Study October 12, 1992 PHUKAN Consulting Engineers & Associates, Inc . [W.O. H92466] PHOTO PLATE NO.7: View of the dam (loo.king from top). Chenega Hydro-Electric Feasibility Study October 12, 1992 PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] PHOTO PLATE NO.8: View of the spillway. Chenega Hydro-Electric Feasibility Study October 12, 1992 I I PHUKAN Consulting Engineers &. Associates, Inc. [W.O. H92466] PHOTO PLATE NO.9: View of the spillway. Chenega Hydro-Electric Feasibility Study October 12, 1992 PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] PHOTO PLATE NO. 10: View of the upper part of the dam. Chenega Hydro-Electric Feasibility Study October 12, 1992 PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] PHOTO PLATE NO . 11: Downstream view of the dam. Chenega Hydro-Electric Feasibility Study October 1 2, 1992 I PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] Chenega Hydro-Electric Feasibility Study October 12, 1992 PHOTO PLATE NO. 12: Downstream view of the dam with the intake pipe. PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] Chenega Hydro-Electric Feasibility Study October 12, 1992 PHOTO PLATE NO. 13: Downstream view of the dam with the cleanup pipe. PHUKAN eoR$.ulting Engineers & Associates, Inc. rw .0. H92466] Chenega Hydro-Electric Feasibility Study October 12, 1992 PHOTO PLATE NO. 14: View of the water intake pipe at the downstream side (away from the dam). PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] Chenega Hydro-Electric Feasibility Study October 12, 1992 PHOTO PLATE NO. 15: Downstream view (looking from top). I PHUKAN ConIulting Engineers" Associates, Inc. fW-O. H92466] Chenega HydFo.-Electric FeaaibiUty Study October 12, 1192 PHOTO PLATE NO. 16: View of the water pipeline away from the dam. -'.--:.' -' ~ .~ ~. ,'~';,' ~~-" PHUKAN ",: """~ Consulting Engineers & Associates, Inc. J~ [W.O. H92466] PHOTO PLATE NO. 17: Water storage tank. Chenega Hydro-Electric Feasibility Study October 12, 1992 I PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] Chenega Hydro-Electric Feasibility Study October 12, 1992 PHOTO PLATE NO. 18: View of the water treatment building (from top). PHUKAN Consulting Engineers & Associates, Inc. [W.O. H92466] Chenega Hydro-Electric Feasibility Study October 12, 1992 PHOTO PLATE NO. 19: View of the Chenega Village (from water storage tank area).