Wynoochee Dam and Lake, Wynoochee River, Washington
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WYNOOCHEE DAM AND LAKE, WYNOOCHEE RIVER, WASHINGTON ( ) Draft ( X ) Final Environmental Statement Responsible Office: U.S. Army Engineer District, Seattle, Washington 1. Name of Action: (X) Administrative ( ) Legislative 2. Description of Action: The Wynoochee Project in Grays Harbor County of southwestern Washington involves construction of a multipurpose con crete gravity dam 663 feet long and 175 feet high* A lake A.A miles long with a surface area of 1,1A0 acres will be created. 3. a. Environmental Impacts: Wynoochee Lake will provide 35,000 acre- feet of water storage for flood control and assure a 385 c.f.s. flow dur ing the low flow period for fishery enhancement and irrigation and for diversion by the city of Aberdeen for industrial and domestic use. Rec reational opportunities will be enhanced with development of 551 acres for picnicking, camping, hiking and other outdoor activities. Adult anadromous fish will be collected below the dam and transported to spawn ing areas above the lake and downstream migrants will be passed through a multilevel low flow outlet works which will also maintain downstream water quality. b. Adverse Environmental Effects: Adverse effects include loss of 5.A miles of resident stream fish habitat and anadromous trout spawning and rearing area, inundation of 1,1A0 acres of big game habitat, loss of timber, other vegetation and habitat for wildlife other than big game and the appearance of buildings in a former wild valley. Compensatory meas ures include management of Wynoochee Lake for a kokanee fishery, hatchery facilities and acquisition of 1,000 acres for intensive big game manage- -ment. A. Alternatives: a. A 295-foot high dam with power generating facilities and a 50-foot high reregulating dam at river miles A2.5 and 37.5, respectively. b. Identical to alternative a, but to be constructed in two stages. c. A two dam project in two stages at river miles A2.5 and 51.8. d. A dam without power generation at river mile A2.5. e. Development of Humptulips River for water supply. f. Development of Satsop River for water supply. 5. Written Comments Received; State of Washington Department State of Washington Department of Game of Fisheries Bureau of Sport Fisheries and State of Washington Department Wildlife of Natural Resources 5. Written Comments Received (cont'd): Bureau of Outdoor Recreation Environmental Protection Agency Bureau of Reclamation Grays Harbor County National Oceanic and Interagency Committee on Outdoor Atmospheric Administration Recreation A public announcement and news release was made to declare the availability of the draft statement to the Public for review and comment. 6. Draft statement submitted to CEQ on: 1 July 1971 Final statement submitted to CEQ on: 1 8 FEB 1372 15 September 1971 Environmental Statement Wynoochee Dam and Lake Wynoochee River, Washington Prepared By U.S. Army Corps of Engineers District Seattle, Washington 1. Project Description The Wynoochee Project i; /Vrays Harbor County of southwestern Washington is 51.8 miles upstream from the Wynoochee River*s confluence with the Chehalis River. The damsite is about 35 miles northerly by road from U.S. Highway 410 near Montesano, Washington. The project is within the boundaries of the Olympic National Forest and requires the acquisition of land owned by Simpson Timber Company. The project site is shown on plate 1. Construction of the Wynoochee Project was originally authorized at river mile 42.5 by the Flood Control Act of 1962 (Public Law 87-874, 87th Congress, 2d Session) for the purposes of water supply, irrigation, hydroelectric power, flood control, recreation and fisheries enhancement. While deletion of hydroelectric power from the project plan resulted in many changes, including selection of a new site, the other basic concepts as authorized by Congress are unchanged. The current benefit-cost-ratio is 1.4 to 1. The main portion of the project is construction of a concrete gravity structure 663 feet long at the top with gravel and rockfill embankments at both abutments, a chute—type spillway on the east bank and two outlet sluices. The dam will be 175 feet high at the center and will form a lake 4.4 miles long and 0.5 mile wide at normal full pool elevation of 800 feet. The lake will have a surface area of 1,140 acres. Additionally, relocation of approximately 6 miles of Forest Development roads and re placement of three bridges will be required. Fish passage facilities include a barrier dam and collection and transport facilities 2 miles below the main structure for adult upstream salmon and trout migrants. A prototype multilevel low flow outlet works is being incorporated into the dam to pass downstream migrants and control the quality of water released downstream. A system of check dams will be installed to maintain adequate transportation water levels for adult up stream migrants in low flow problem areas when Aberdeen's Industrial water needs leave inadequate transportation water downstream of the diversion at mile 8.1. This is estimated to occur approximately 30 years after project completion. Recreation and visitors facilities are included in the project. These facilities, except for the visitors center at the dam itself, will be administered by the Forest Service and will include parking, camping, picnicking and hiking areas. Sixty-eight percent of the construction and development of the project has been completed. The main dam construction was initiated in August 1969 and is scheduled for completion in November 1972. The reservoir area is cleared of timber and prepared for inundation and upstream fish passage facilities are in operation. Roads are being relocated and one of three bridges has been replaced. Specific recreation and camping areas have been tentatively planned. 2. Environmental Setting Without the Project The Wynoochee River originates as a precipitous stream on the southern slopes of the Olympic Mountains at an elevation of approximately 3,000 feet. It flows 67 miles in a southerly direction with gradually decreas ing gradient through a forested valley, a twisting canyon, gravel bars confined by steep valley slopes and finally lowland pastures and fields to its confluence with the Chehalis River near Montesano, Washington. The lower mile of the Wynoochee is within the tidal influence of the Pacific Ocean. The basin encompasses an area of 196 square miles and is bounded on the east by the Satsop, on the northwest by the Humptulips, and on the southwest by the Wishkah River Basins. The largest tributar ies of the Wynoochee are Black Creek, Schafer Creek and Big Creek which enter it at river miles 5.5, 24 and 49, respectively. The climate of the Wynoochee watershed is typical of the midlatitude west coast with cool and relatively dry summers and mild, wet and rather cloudy winters. Rainfall is abundant throughout the watershed but varies seasonally and locally. November, December and January are the wettest months, July and August the driest. Mean annual precipitation at Aberdeen is about 80 inches but increases to 145 inches at Wynoochee Dam site. Industry in the Wynoochee Valley above Schafer Creek is devoted solely to the production of timber. Below Schafer Creek the principal land use is production of hay and pasture for dairy and beef cattle. Montesano, near the confluence of the Wynoochee and Chehalis Rivers, is the nearest community. Aberdeen and Hoquiam are important, growing commercial and industrial centers. Principal human use of the Wynoochee Basin water is by the city of Aberdeen for industrial purposes. The diversion of about 100 c.f.s. causes critically low flows for adult salmonid upstream migration in the lower river during the early fall months 2 out of 7 years. There is presently a diversion of 3 c.f.s. for irrigation. Rivejrflows have varied from a low of 100 c.f.s. to a high of 33,000 c.f.s. (during the maximum flood of record in 1955). Average annual flow is 1,250 c.f.s. at the indus trial water diversion. Flood damage to agricultural lands, buildings, roads and utilities in the Wynoochee Valley averages $30,000 annually. Commercial development of the Wynoochee Valley is minor. There is a commercial gravel pit at mile 3.2 and the Aberdeen's industrial water diversion is at mile 8.1. The Simpson Timber Company operates a major logging facility at Camp Grisdale, near mile 48, and timber is harvested from most of the upper basin. The forest cover of the Wynoochee River drainage is characterized by dense stands of mature Douglas-fir interspersed with western red cedar, western hemlock and Sitka spruce. Logged over areas throughout the drainage contain second growth timber of various age classes. Understory growth is primarily vine maple, rhododendron, dogwood and willow. In the more open coniferous stands and newly logged areas salal, huckleberry, evergreen and himalaya blackberry, thimbleberry, salmonberry, swordfern, fireweed and Oregon grape form dense ground cover. There are occasional stands of deciduous trees in the bottomlands. Important migratory runs of Chinook, coho and chum salmon, steelhead and searun cutthroat trout and Dolly Varden use the Wynoochee River and tributaries for spawning and rearing purposes from its lower reaches to Wynoochee Falls 62 miles upstream. Offspring of parent salmon populations contribute to commercial ocean troll and Grays Harbor gillnet fisheries as well as sports fisheries in the Pacific Ocean, Grays Harbor, Chehalis River and Wynoochee River. The anadromous trout and steelhead populations contribute to the sport fishery of the Chehalis and Wynoochee Rivers. Resident fish in the Wynoochee drainage contribute to the sport fishery of the Wynoochee River and its tributaries. These fish include cutthroat and rainbow trout, whitefish and Dolly Varden. Suckers, squawfish and other non-game species are also present.