Report of the Secretary of the Army
on Civil Works Activities for Fiscal Year 1996
Department of the Army Corps of Engineers
Extract Report of the Walla Walla District

Columbia River Fish Mitigation Program (Walla Walla Projects), Oregon, Washington, and Idaho

Existing project. The eight Corps hydroelectric projects on the Columbia and Snake Rivers have been identified as a major contributing factor in causing mortality to downstream migrating juvenile salmon and steelhead. Without adequate bypass facilities to guide these juvenile fish away from the power turbines at the dams, mortalities incurred through project passage severely impact the commercial, recreational, and Indian fisheries. The Corps has recognized the need to reduce juvenile mortality and has undertaken bypass measures that include mechanized fish bypass systems with barge and truck transportation. Spill, as an additional bypass route over the spillways, has been used to divert fish from entering turbine units; but it is a significant adverse economic factor due to lost power revenues. Congress passed and the President signed the fiscal year 1989 Energy and Water Development Appropriation Act (PL 100-371), which mandated the expenditure of funds for the design, testing, and construction of new or improved fish bypass facilities for the Columbia River Fish Mitigation projects. Completion of bypass and transportation facilities will significantly increase the survival of migrating downstream juvenile fish. The mitigation study will determine the overall scope of the fish mitigation facilities for these Columbia and Snake River dams. The mitigation study project was added to the President's Fiscal Year 1991 budget.

The plan of improvement includes the following facilities: 1) Ice Harbor: screens, new gantry crane, collection bypass facility, intake gate raise, spillway deflectors, surface bypass, fish ladder temperature control; 2) Little Goose: screens, gantry crane modification, collection bypass facility, outfall pipe, remaining double-length submerged traveling screen/submerged bar screen, prototype vertical barrier screens, remaining vertical barrier screens, fish ladder temperature control, fallout fences, gate raise, deck screen modifications, and surface bypass; 3) Lower Granite: juvenile fish facility, gantry crane, gate raise, outfall pipe, fish barges, screens, remaining double-length submerged traveling screens/submerged bar screens, additional moorage facility, fish slot closures, juvenile facility improvements, barge exit modifications, deck screen modifications, fish ladder temperature control, surface bypass, fallout fences; 4) Lower Monumental: hold/load and collection bypass facility, screens, pit-tag facility, barge load facility modifications, barges, gate-raise modifications, gantry crane, screen repair pit, fish ladder temperature control, surface bypass; 5) McNary: gantry crane, screens, hold/load facility, gate-raise modifications, submerged vertical barrier screens remaining, submerged double-length screens remaining, debris/screens, tilted weirs fish ladder, maintenance facility, fish ladder exits, hold/load facility, gantry crane modifications; and 6) a mitigation study that analyzes long-term alternatives to mitigation for fish losses at Corps dams on the Columbia and Snake Rivers.

The fully-funded Federal project cost is estimated at $819,800,000 for Walla Walla projects.

Local cooperation. None required.

Operations during fiscal year. At Ice Harbor Dam, a contract was completed for submerged bar screens and submerged traveling screens. At Little Goose dam, a contract was completed for the gantry crane. At Lower Monumental Dam, contracts for the screen repair pit, fish holding/loading facilities, collection/bypass facility, submerged traveling fish screens, and a pit-tag facility were all completed. At Lower Granite dam, contracts were completed for the barge moorage facility expansion, slot closure/Wagner Horn, gate-raise modifications, and the juvenile fish support facility.

A prototype surface bypass collector was constructed and tested at Lower Granite dam. The construction cost was $8,700,000, and the cost of the test was $3,000,000. Plans for a second test in 1997 are proceeding. Phase II of the Gas Abatement Study was initiated. This is a joint study between Portland District and Walla Walla District, which will make recommendations on solutions to high levels of dissolved gas in the reservoirs resulting from high spill at Snake and Columbia River projects. A draft of the Interim Status Report on the Snake River Feasibility Study was submitted to National Marine Fisheries Service in September. This report selects the permanent natural river alternative for continued evaluation in the feasibility study.

Fiscal year costs were $53,665,872. Total project costs are $228,032,511.