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HomeMy WebLinkAboutFive Mile Creek Hydroelectric Project Fish Habitat Impact Anaylsis Memo - May 2020 - REF Grant 7040012polarconsult alaska, inc. 1503 West 33rd Avenue, Suite 310 Anchorage, Alaska 99503-3638 Phone: (907) 258-2420 FAX: (907) 258-2419 M E M O R A N D U M DATE: May 22, 2020 TO: Martin Finnesand, CEO, Chitina Electric, Inc. FROM: Joel Groves, PE Polarconsult Project Manager SUBJECT: Five Mile Creek Hydro Project - Fish Habitat Impact Analysis Memo CC: Mark Somerville, ADFG Area Biologist 1.0 BACKGROUND AND INTRODUCTION Chitina Electric, Inc. (CEI) is developing a 250-kW run -of -river hydroelectric project on Five Mile Creek to provide electricity to the community of Chitina (Figure 1). CEI currently relies on diesel-electric generators to provide 100% of the community's electricity. As proposed, the hydro project will reduce diesel fuel use for electricity generation by approximately 36,000 gallons annually. Usage would decrease from existing 37,400 gallons annually to 1,400 gallons annually with the project. Excess energy generated by the project can also be used to heat community buildings, achieving a further reduction in heating fuel usage in the community by approximately 7,000 gallons per year, for a total annual fuel savings with this project of 43,000 gallons annually. Direct environmental benefits from this project include: - Reduced risk of fuel spills into the Copper River, its tributaries, and other area waters by eliminating routine fuel haul along the Richardson and Edgerton Highways by approximately 10 to 12 truck trips per year. - Elimination of approximately 480 tons of CO2 emissions annually. - Proportionate reduction in other diesel power plant stack emissions such as NOX, SOX, soot and hydrocarbon residuals, carbon monoxide, and other trace pollutants. This memo: 1. Summarizes project and resource information pertinent to fisheries habitat in Five Mile Creek, 2. Reviews expected project impacts on fish habitat, and 3. Recommends mitigation measures appropriate to protect fish habitat. Figure 1: Project Location Map FAIRBANKS i FIVE BASIN THIS MILE CREEK, PROJECT THIS PROJECT EpERTp J _ JUNEAL}� �� H�`HWAY CHITIN -A 'l RIVER CHITIN - ANCHORAGE 4 COPPER 0 5 J„K� RIVER LOCATION MAP PROJECT VICINITY MAP Based on analysis of available information, no flow -related mitigation measures are warranted to project fish habitat. 200522M-5MIFISHHABIT ATM EMO.DOC Five Mile Creek Hydro Project — Chitina, Alaska Chitina Electric, Inc. Fish Habitat Impact Analysis Memo Polarconsult Alaska, Inc. 2.0 PROPOSED PROJECT The project description that follows is based on 35-percent design and current information on permitting and regulatory matters. All project details are subject to change as design and permitting processes are completed. The proposed hydro project will include the following major components, shown on Figure 2: - New access roads, trails, and work pads for the project consisting of approximately 8,200 linear feet and 4 acres of total development footprint. The project would also utilize portions of the existing jeep trail that parallels the north side of Five Mile Creek for access and portions of the penstock route. This trail is an ANCSA 17b route (# EIN7). Public access along this trail may be subject to temporary closures during construction and infrequent maintenance events for public safety reasons, but would otherwise not be restricted by this project. The project penstock would cross the Edgerton Highway %- mile north of Five Mile Creek. - Approximately 350 feet of overhead primary electric distribution extension from existing CEI pole #3N to the new hydro powerhouse and approximately 900 feet of new control cable underbuild on the existing/new utility poles between the hydro and diesel powerhouses. - A concrete diversion structure located at river mile (RM) 2.22 of Five Mile Creek. This structure will screen and admit up to —4.1 cubic feet per second (cfs) of water into the project penstock. The maximum impoundment depth will be approximately 10 feet, providing a project headwater elevation of 1,548 feet above sea level. - An 8,650 foot long penstock to convey project water from the diversion down to the powerhouse. The nominal 12- to 18-inch pipe would be buried for its full length. It would cross Five Mile Creek at about RM 0.35. This crossing would be either underground or via a pipe bridge. - An approximately 24-foot by 24-foot powerhouse located between the existing Wrangell View RV park and Alaska Department of Transportation and Public Facilities (ADOT&PF) airport property between Airport Road and Five Mile Creek. The powerhouse site would include a new approximately 200-foot long driveway off Airport Road and an approximately 100-foot by 100-foot building pad. The powerhouse will house a Pelton turbine, 250 kW 480-volt three-phase synchronous generator, generator switchgear, controls, hydraulic power unit for turbine inlet nozzle regulation, electric load bank for frequency control, station service transformer, and associated appurtenances typical of a hydro plant. The plant will be capable of stand-alone black - start operation and parallel operation with the diesel plant depending on utility load, water availability, and operator direction. - Water would be discharged via an approximately 200 foot long buried pipe from the turbine tailrace beneath the powerhouse back to Five Mile Creek. The discharge location would be approximately RM 0.29. Key project parameters are summarized in Table 1. May 22, 2020 Page 2 of 18 Five Mile Creek Hydro Project - Chitina, Alaska Fish Habitat Impact Analysis Memo Chitina Electric, Inc. Polarconsult Alaska, Inc. Table 1: Five Mile Creek Hydro Project Parameters Parameter Value Intake Location River mile 2.22 Design Flow -4.1 cubic feet per second Normal Headwater Elevation 1548 feet ASL Penstock Length 8,650 feet Penstock Losses at Design Flow - 46 feet (5%) Powerhouse Finish Floor Elevation 615 feet ASL Project Gross Head 933 feet Project Net Head at Design Flow -887 feet Turbine Generator Efficiency -82.5% Installed Capacity / Rated Output 250 kW Tailwater Elevation -610 feet ASL Tailrace 200 feet of pipe Tailrace Discharge Location River mile 0.29 Figure 2: Five Mile Creek Hydro Project Layout NOTES' RM Q.29 1. CONTOURS ARE 25—FT INTERVAL, TAILRACE BASED ON LIDAR SURVEY. HYDRO TRIBUTARY `L10 OLD HIGHWAY BED EDGERTON HIGHWAY (TO GLENALLEN) PENSTOCK ROUTE EXISTING JEEP TRAIL (ANCSA 17b EASEMENT EIN7)RM q HYDRO INTAKE May 22, 2020 Five Mile Creek Hydro Project — Chitina, Alaska Fish Habitat Impact Analysis Memo Chitina Electric, Inc. Polarconsult Alaska, Inc. 3.0 LOCAL ENVIRONMENT 3.1 Hydrology Five Mile Creek is a minor creek that drains a north-west facing mountainous basin located in the northerly periphery of the Chugach Mountains north of the Gulf of Alaska. The total basin measures 15.38 square miles in area (Figures 1 and 4). The basin's westerly divide consists of several mountain summits and interconnecting saddles and ridges at 4,500 to 5,500 foot elevation. The upper —1/3rd of the basin is alpine tundra, and the lower—2/3rds are vegetated by mature spruce/alder forest. The creek exits the mountains onto the Copper River valley floor, traverses its roughly -half -mile long alluvial fan and discharges to the Copper River at 500 foot elevation. Table 2 summarizes Five Mile Creek subbasins significant to this project. These subbasins are shown on Figure 4. Two stream gauges were installed on Five Mile Creek from 2009 to 2010, one near the proposed intake site at RM 2.27 and a second at the outlet of the highway culvert at RM 0.52. These gauges collected nearly a full year of hydrology data for the creek. Review against regional concurrent and long-term hydrology and precipitation records indicate that the 2009 — 2010 Five Mile Creek hydrology period of record (Figure 3) represents an average year.' Table 2: Significant Five Mile Creek Subbasins Subbasin Upstream End of Reach Downstream End of Reach Subbasin Area (square miles) Cumulative Basin Area (square miles) Above Project Intake Headwaters RM 2.22 12.12 12.12 Bypass Reach RM 2.22 RM 0.38 1.66 13.78 Tributary "L1" RM 0.27 RM 0.27 1.54 15.32 Downstream Reach RM 0.27 RM 0.00 0.06 15.38 TOTAL 15.38 Figure 3: Five Mile Creek Hydrograph 100 R 3 ni 90 Average Daily Flow v a U_ 80 —21-Day Centered Moving Average a o 70 to 60 a ca 50 a°1i °r° 40 L •— U ao a� 30 QJ 20 1, a D 10 1 o 8/15/09 9/26/09 11/7/09 12/19/09 1/30/10 3/13/10 4/24/10 6/5/10 7/17/10 8/28/10 1 Clifton 2011, Brailey 2020. May 22, 2020 Page 4 of 18 Five Mile Creek Hydro Project - Chitina, Alaska Fish Habitat Impact Analysis Memo Chitina Electric, Inc. Polarconsult Alaska, Inc. Figure 4: Five Mile Creek Subbasins n0. .TRIBUTARY 01-1' SUBBASIN DOWNSTREAM SUBBASIN (1.54 SQ.MI.) (0.08 SQ.AiII.) 0 FIVE MILE CREEL( RM 0.5 DRAINAGE BASIN - PERCHED HIGHWAY CULVEi�� PROBABLE LIMIT OF FISH �] (15.38 SQ.MI.) _ - HABITAT F - PROJECT SUBBASIN (12.12 SQ.MI.) RM 2.22 PROPOSED HYDRO DIVERSION/ INTAKE sr E RM 0.38 TAILRACE :J)ISCHARGE } . " BYPASS REACH F SUBBASIN _ (1.66 SQ.MI.) 2 Y �- fJ Imo. L� cww- - r CHmNA 0 SCALE IN IIRES _ May 22, 2020 Page 5 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Fish Habitat Impact Analysis Memo Chitina Electric, Inc. Polarconsult Alaska, Inc. 3.2 Fisheries Resources The lower 0.52 miles of Five Mile Creek from its mouth on the Copper River up to the Edgerton Highway culvert (the 'habitat reach') traverses the full alluvial fan of Five Mile Creek, and is accessible to resident and anadromous fish that are present in the Copper River. The highway culvert is a 160 foot long, 10-foot diameter single corrugated metal pipe culvert set at a slope of 5.4%.2 The outlet of the highway culvert is perched above the stream bed, resulting in an approximately four to six-foot tall waterfall at the culvert outlet. The waterfall and culvert are significant and potentially complete barriers to all upstream fish passage .3 Above RM 0.52, Five Mile Creek flows within a steeply incised canyon upstream to about RM 2.1. This reach is characterized by steep gradients, numerous bedrock exposures, and coarse bed aggregate (boulders and megaboulders).4 Several waterfalls and bedrock chutes occurs upstream of RM 0.52, which are likely also fish passage barriers. The creek thalweg profile is shown on Figure 5. While anadromous fish are documented in the Copper River below Five Mile Creek and the habitat reach of Five Mile is accessible to anadromous fish, the creek is not included in ADFG's Anadromous Fish Atlas.s Fisheries surveys conducted for this project in 2011 concluded that the habitat reach could support some small degree of salmon spawning and rearing habitat at low flows. Viability of redds during natural winter low flow conditions is unknown, and rearing habitat would probably be marginal due to seasonally high flows.6 Minnow trapping in the Copper River at the creek mouth (RM 0.0), at the highway culvert plunge pool (RM 0.5), and at the upper gauging station (RM 2.27) in June 2011 found a single 110 mm long Dolly Varden at the creek mouth. No fish were documented in Five Mile Creek upstream of the mouth by trapping or visual observations.' Polarconsult's field observations in June 2019 concluded that the marginal habitat reach of Five Mile Creek is relatively better in the lower half of the habitat reach due to less coarse substrate and a lower gradient on the creek's lower alluvial fan. The mouth of a significant left -lateral tributary (Table 2, Figure 4) also appeared to be a more favorable low -gradient habitat area that is more sheltered by local topography from the main channel's frequent flood events. ems: Figure 5: Five Mile Creek Thalweg Profile 1. SEVERAL WATERFALLS AND ROCK CHUTES 15 TO 25 FEET TALL EXIST IN RM 0.6 TO 2.0 REACH) 2. GRID SCALE IS 0.1 MILE HORIZONTAL AND 100 FT VERTICAL. RM: RIVER MILE WF: 15+ FT HIGH WATERFALL / BEDROCK CHUTE RM 2.22 RM 0.00 - MOUTH ON COPPER RIVER HYDRO INTAKE RM 0.27 - MOUTH OF LEFT -LATERAL TRIBUTARY 'L1' RM 0.29 - TAILRACE DISCHARGE RM 0.52 - EDGERTON HIGHWAY 1500 gym• z ADOTPF 1970 at sheet 13. 3 ABR 2020a at page 3. See Photographs 9 and 10 show the culvert outlet condition. 4 See Photographs 11 through 18 for creek conditions above RM 0.52. 5 ADFG 2020. 6 ABR 2020a at page 3. ABR 2020a at page 6 (Table 1) and page 7 (Figure 1). May 22, 2020 Page 6 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Fish Habitat Impact Analysis Memo Chitina Electric, Inc. Polarconsult Alaska, Inc. 4.0 PROJECT IMPACTS The principal impact of the hydro project with regard to fisheries resources would be the diversion of up to —4.1 cfs from the creek at RM 2.22 and return of this water back to the creek at RM 0.29. This would reduce flows in the bypassed reach of the creek (RM 2.22 to 0.29) relative to natural conditions, including in the upper 0.23 miles of the habitat reach from RM 0.52 down to RM 0.29. Flows from RM 0.29 down to the mouth would not be altered by the project. Water quality would also not be significantly altered by the project. Figure 6 shows the natural and modified hydrograph at the top of the habitat reach (RM 0.52). Flow at the top of the habitat reach would be maintained by incremental inflows from the bypass reach, subsurface flow beneath the diversion structure, and flows spilled at the diversion in excess of project capacity and/or demand. 75 N Ln 0 50 V CO f11 25 0 0 a 9 ra m 3 0 '1 0 Figure 6: Five Mile Creek Hydrograph at Top of Habitat Reach with Project 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec Flow requirements for the habitat reach have not been quantitatively defined. The qualitative effects of reduced water quantity in the upper habitat reach (RM 0.52 to RM 0.29) were assessed using the 'Montana Method'.$ The Montana Method rubric of coupling quantitative flow ranges to qualitative habitat conditions is commonly used for analysis of habitat needs and mitigation options. Table 3 presents Montana Method criteria applied to Five Mile Creek. 8 Tennant 1976. May 22, 2020 Page 7 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Chitina Electric, Inc. Fish Habitat Impact Analysis Memo Polarconsult Alaska, Inc. Table 3. Montana Method Flow Regimens Applied to Five Mile Creek Habitat Reach Narrative Description of Flows Recommended Base Flow Regimens percent of Average Flow 1 Five Mile Creek Flow (cfs) Winter 1 Summer 1 Winter 1 Summer 1 Flushing or Maximum 200% - 53 cfs Optimum Range 60 — 100% 1.7 — 2.8 16 — 27 cfs Outstanding 40 — 60% 60+% 1.1-1.7 16+ cfs Excellent 30 — 40% 50 — 60% 0.8 —1.1 13 —16 cfs Good 20 — 30% 40 — 50% 0.6 — 0.8 11-13 cfs Fair or Degrading 10 — 20% 30 — 40% 0.3 — 0.6 8 —11 cfs Poor or Minimum 10 — 20% 10 — 30% 0.3 — 0.6 3 — 8 cfs Severe Degradation 0 —10% 0.0 — 0.3 0 — 3 cfs Notes: 1. Based on Five Mile Creek hydrology at top of habitat reach. Annual average flow is 14.8 cfs. 'Winter' is November 1 to April 30, with average flow of 2.8 cfs. 'Summer' is May 1 to October 31, with average flow of 26.7 cfs. The transition from winter to summer is reasonably abrupt as seen on Figure 3. The transition from summer to winter is not as clearly delineated, with a series of recession curves with 'winter' characteristics interrupted by periodic rain events that return the creek briefly to 'summer' characteristics. As a result, the October 31 seasonal transition is more subjective. With the proposed project, average winter flow at the top of the habitat reach (RM 0.52) will meet or exceed Montana Method "good" criteria, and average summer flow at the top of the habitat reach will meet or exceed Montana Method "outstanding" criteria. Instantaneous flow conditions may result in episodes of "fair" habitat quality during both winter and summer seasons. Below the tailrace at RM 0.29, the flow regime would be unchanged from natural conditions. 5.0 CONCLUSIONS AND RECOMMENDATIONS Given that the upper habitat reach (RM 0.52 to RM 0.29) is marginal fish habitat under natural conditions, meeting or exceeding "good" criteria with excursions into "fair" criteria adequately protects the integrity of the stream and no mitigation for impacts to fisheries habitat is recommended for this project. Fish passage in the project's bypass reach will be provided by common high flow events. May 22, 2020 Page 8 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Chitina Electric, Inc. Fish Habitat Impact Analysis Memo Polarconsult Alaska, Inc. PHOTOGRAPHS To the extent practical, photographs have been organized starting at the creek mouth on the Copper River (RM 0.0) and proceeding upstream to the 2014 intake site (RM 2.27). Photograph 1. Overview of Fivemile Creek and existing improvements looking downstream from terrain above the Edgerton Highway. Creek reach from RM 0.0 up to 0.5 is visible in this photograph. June 6, 2019. RM 0.0 Mouth of Fivemile Creek Airport RV Park Clinic Diesel Power Plant RM 0.5 Edgerton Culvert Outlet Highway Copper F' May 22, 2020 Page 9 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Fish Habitat Impact Analysis Memo Chitina Electric, Inc. Polarconsult Alaska, Inc. Photograph 4. Upstream view of Fivemile Creek substrate at RM 0.30. - Small cobbles dominate with significant fractions of large cobble and gravel also present. June 6, 2019. .1e IX L May 22, 2020 Page 10 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Fish Habitat Impact Analysis Memo Chitina Electric, Inc. Polarconsult Alaska, Inc. Photograph 6. Upstream view of Fivemile Creek at RM 0.40. Note cobble bar and active cut bank beyond. June 6, 2019. RM IL ikk mot. . fir-, `-L• ... ; .' . { --� _ _ , a, , � _ ,' _ May 22, 2020 Page 11 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Fish Habitat Impact Analysis Memo Chitina Electric, Inc. Polarconsult Alaska, Inc. Photograph 8. Downstream view of Fivemile Creek at RM 0.50, Riffle below highway ?� culvert plunge pool. June 4, 2019. May 22, 2020 Page 12 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Fish Habitat Impact Analysis Memo Chitina Electric, Inc. Polarconsult Alaska, Inc. Photograph 9. Upstream view of Fivemile Creek at RM 0.50, highway culvert outlet. June 4, 2019. t . May 22, 2020 Page 13 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Chitina Electric, Inc. l Photograph 11. View of Fivemile Creek at RM 0.55, highway culvert inlet. June 4, 2019. e`f 0 Fish Habitat Impact Analysis Memo Polarconsult Alaska, Inc. 01- May 22, 2020 Page 14 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Chitina Electric, Inc. Fish Habitat Impact Analysis Memo Polarconsult Alaska, Inc. Photograph 14. Upstream view of Fivemile Creek from RM 0.58. Reach immediately upstream of alternate powerhouse site W. June 4, 2019. May 22, 2020 Page 15 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Chitina Electric, Inc. Photograph 15. Upstream view of Fivemile Creek and lower canyon viewed from north rim. Reach from approximately RM 0.65 to RM 0.75 is visible. June 5, 2019. k- Fish Habitat Impact Analysis Memo Polarconsult Alaska, Inc. May 22, 2020 Page 16 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Fish Habitat Impact Analysis Memo Chitina Electric, Inc. Polarconsult Alaska, Inc. Ile Photograph 18. Upstream view of p Fivemile Creek from RM 2.27, upper'.:;.:;:; stream gauging station and 2014 " intake site. June 5, 2019. - J ' �`.-:�%���� : v �.._ !,• Sz. :fir vxZwl . ='I.U. RIC-.��'iS•.....�H ��V:•�. l i' mod' fig. W, leit fr-.'. H'. May 22, 2020 Page 17 of 18 Five Mile Creek Hydro Project — Chitina, Alaska Fish Habitat Impact Analysis Memo Chitina Electric, Inc. Polarconsult Alaska, Inc. REFERENCES ABR 2012a. ABR, Inc. Five Mile Creek Hydro Project: Fish and Habitat Studies, June Site Visit Report. June 2011. Anchorage, AK. ABR 2012b. ABR, Inc. Environmental Research and Services. Five Mile Creek Hydro Project: Aquatic Resources Data Gap Analysis. July 2011. Anchorage, AK. ADFG 2020. Alaska Department of Fish and Game. Catalog of Waters Important for the Spawning, Rearing, or Migration of Anadromous Fishes. Accessed May 15, 2020. https://www.adfg.alaska.gov/sf/SARR/AWC/ Anchorage, AK. ADOTPF 1970. Alaska Department of Transportation and Public Facilities. Chitina North Grading, Drainage & Experimental Insulation Installation, S-0851(26), As - Built Plans. Completion Date August 31, 1970. Brailey 2020. Brailey Hydrologic. Five Mile Creek streamflow record extension and flood frequency analysis. March 2020. Anchorage, AK. Clifton 2011. Clifton Labs, Ltd. Chitina Hydroelectric Project Energy Production. April 11, 2011. Seattle, WA. Polarconsult 2020. Polarconsult Alaska, Inc. Hydrology Memo for Five Mile Creek Hydroelectric Project — Chitina, Alaska (Revision 1). February 28, 2020. Anchorage, AK. Tennant 1976. Tennant, Donald Leroy. In stream Flow Regimens for Fish, Wildlife, Recreation, and Related Environmental Resources. Fisheries, Vol 1, No. 4. July -August 1976. Pages 6 — 10. May 22, 2020 Page 18 of 18