Historically, both summer steelhead and spring Chinook salmon migrated to their spawning grounds in the upper Deschutes, Metolius and Crooked Rivers. Although Pelton Round Butte was constructed with fish-passage facilities, the downstream system failed.
Fish passage system completed
PGE and the Confederated Tribes of Warm Springs have completed a new fish passage system that allows salmon and steelhead to migrate past three Deschutes River three dams for the first time since 1968.
The downstream fish passage problem was created in large part by the currents in Lake Billy Chinook (PDF) that confused juvenile salmon and steelhead seeking downstream migration. To address the problem, PGE and the Tribes built a 273-foot underwater tower that rises from the lake bottom. The tower alters the current (PDF), attracting migrating fish.
Juvenile fish are screened at the intake and trucked downstream of the dams for release on their journey to the Pacific. The facility also allows PGE to manage water temperatures at project outflow in the Deschutes River to approximate temperatures that would be expected at that point in the river if the dams weren’t there. Returning adults are captured at the Pelton trap, trucked and released upstream at a new adult release facility into Lake Billy Chinook. View a map of the trucking process (PDF).
These improvements have reopened a new fish passage area of 226 stream miles (PDF) to salmon and steelhead migration.
Re-establishing runs of steelhead and Chinook salmon to the Upper Deschutes, Metolius and Crooked Rivers is a historic undertaking. PGE and the Confederated Tribes of Warm Springs are dedicated to the success of this project in the long term.
Reducing handling of fish
As the runs of steelhead and salmon become more firmly established, PGE and the Tribes plan to add facilities that will allow the fish to migrate past the dams with less human interaction:
- A fish ladder, built when Pelton Dam was constructed, runs from the base of the re-regulating dam (most downstream dam) to the top of Pelton (middle dam). This ladder could be reactivated for upstream passage with some modernization.
- To allow fish to pass upstream from Lake Simtustus to the top of Round Butte (dam farthest upstream), a new facility will need to be constructed. The Round Butte tramway, which carries fish in a 500-gallon bucket above the dam, was removed to make way for construction of the underwater tower. Rebuilding this tramway is one option that will be evaluated.
- An existing trap at the top of Pelton Dam will be reactivated to capture downstream-migrating smolts from Lake Simtustus and transport the juvenile fish below the re-regulating dam during spring.
PGE and the Tribes are working on ongoing supporting projects that will enhance the river both upstream and downstream:
- Large trees that fall naturally into Lake Billy Chinook are being transported below the dams so they can continue their way down the river and provide streamside habitat as they did before the dams were built. Their movement down the Deschutes River is being monitored annually.
- Nearly two miles of stream bed on Trout Creek, a steelhead spawning stream, have been restored. Trout Creek is located 11 miles downstream of the re-regulating dam.
- Gravel beds below the dams are being studied and more gravel has been deposited for fish habitat.
In addition to these projects, PGE and the Tribes have established the Pelton Round Butte Fund to assist the efforts of local watershed and conservation groups and public agencies. This fund of more than $20 million supports various fish passage and habitat improvement measures in the Deschutes Basin. PGE and the Tribes will continue to monitor the whole fish passage project to determine how well the salmon and steelhead are doing and what is needed to support their return to the upper reaches of the rivers.