The scheme, in Oregon, will see construction of the 84m high underwater “Selective Water Withdrawal Tower” and collector to function as both a mechanism for fish collection and water flow for power generation. PGE said is it the only known tower of its type and is scheduled to be operational by about the second quarter of 2009.

By designing the tower to draw water from both the surface and bottom of Lake Billy Chinook, the tower will alter the currents to attract fish into the collection facility. It will also lower temperatures in the lake and the lower Deschutes river to be closer to pre-damming conditions.

Construction work is being undertaken by Barnard Construction Co, Dix Corp, and Thomson Metal Fab. Design of the tower and collector system was done by CH2M Hill, EES Consulting, and ENSR/Aecom Technology Corp in collaboration with PGE Engineering.

Associated projects in the fisheries protection plan include releasing salmon and steelhead fry into upstream creeks and streams, improving habitats throughout the catchment and monitoring fish behaviour.

Pelton Round Butte is the only US hydro plant that is co-owned by a utility and a Native American tribe – Portland General Electric (PGE) and the Confederated Tribes of the Warm Springs Reservation. The plant has an installed capacity of 465MW and generates approximately 1,500GWh annually, which PGE said it about 9% of its power generation mix.

The Pelton Round Butte scheme – consisting of the Pelton and Round Butte dams – has been certified by the Low Impact Hydropower Institute (LIHI) following the fish restoration plans. PGE said the facility provides about 50MW of its renewable energy portfolio.