Report of the Secretary of the Army
on Civil Works Activities for Fiscal Year 1994
Department of the Army Corps of Engineers
Extract Report of the Walla Walla District

Dworshak Dam and Reservoir, Idaho

Existing project. The project includes a dam, powerplant, and appurtenant facilities. Project provides for flood control, navigation, hydroelectric power generation, recreation, and area redevelopment. The reservoir has a normal operating range between the elevations of 1,600 and 1,445 mean sea level (msl). The reservoir has a gross storage capacity of 3,468,000 acre-feet (2 million acre-feet of which are effective for both local and regional flood control and for at-site and downstream power generation). In addition, the reservoir, extending 53 miles into rugged and relatively inaccessible timberland, provides important transportation savings in connection with movements of marketable logs. The reservoir is habitat for elk, deer, and other wildlife. The dam structure is about 3,300 feet long and about 717 feet above the streambed. Fish passage is not feasible due to the height of the dam. A hatchery has been built below the dam to assure continuance of anadromous fish runs. The Powerhouse has two 90,000 kilowatts (kw) and one 220,000 kw generating units in operation, for a capacity of 400,000 kw. Provisions had been made for three additional 220,000 kw generating units, for an ultimate installed capacity of 1,060,000 kw, and a reconnaissance report justifying the feasibility and cost benefits for the addition of a 200,000 kw fourth generating unit was completed in Fiscal Year 1978. However, environmental and economic studies on additional generating units have been curtailed due to public opposition. Unit 4 is undeveloped. Units 5 and 6 were deauthorized in Fiscal Year 1990. Unit 4 was deauthorized in Fiscal Year 1995. Principal project data are set forth in table 39-J.

Construction of the project started in July 1966, was placed in operation in 1972, and was completed in 1986. Since the project became operational in June 1972, it has prevented about $737,000 (adjusted to October 1994 price index) in potential flood damages. Power generation through September 1994 was 35.13 billion kilowatt hours.

Eighty mini-recreation sites have been established along the reservoir shoreline. Each site includes at least a picnic table, U.S. Forest Service-type fireplace, and chemical toilet. Some of the sites have several picnic tables. Dent Acres and Freeman Creek recreation sites are open to the public. Facilities consist of a boat-launching ramp, boat docks, car-trailer parking, comfort stations, and fully-developed overnight camping.

Local cooperation. None required.

Operations during fiscal year. Operation and Maintenance: Development of wildlife habitat browse continued on project lands to provide winter browse for elk and deer. Work initiated and partially completed on Big Eddy boat ramp extension. During the fiscal year, 960 million kilowatt hours of electrical power were generated by the three generating units.

Dworshak National Fish Hatchery (DNFH) operations were again free of IHNV disease in egg incubation and early rearing stages since completion of the hatchery water supply line from Dworshak Reservoir. The 6,500 gpm received from the Clearwater Fish Hatchery line is sufficient to allow eggs and fry to be raised in reservoir water. However, a loss of fish to IHNV, followed by Ich disease occurred after fish were removed from the "clean" reservoir supply to the outside ponds on pumped river water. This loss reduced the number of smolts released to 1,823,877 or nearly 500,000 fish below the migration goal of 2,300,000 steelhead. Fish size was on target, although lower numbers reduced production to 280,377 pounds as compared to 323,305 in 1993. For 1994, approximately 7.2 million eggs were collected from a return of 3,757 adult steelhead. A total of 2.45 million eyed eggs were shipped to Magic Valley and Clearwater fish hatcheries. The DNFH also released 1,302,687 spring chinook weighing 75,386 pounds, or nearly three times the production of the previous year. Spring chinook returns to Dworshak for 1994 were only 67 fish, as compared to 1993's total of 823. It is anticipated that this year's low return will fill only 10 percent of the hatchery's chinook production capacity. The steelhead return to the Columbia River this year was down significantly from 1993. Only 160,000 were counted in 1994 compared to over 189,000 in 1993. These lower numbers carried over into the Snake River, where 45,000 steelhead were counted compared to last year's record run of 73,000 steelhead.