OROFINO, ID – A hydraulic fluid leak from a small hydropower plant at Clearwater and Dworshak Fish Hatcheries was quickly contained after staff detected an oily sheen in the fish-rearing raceways early Wednesday, Feb. 26.
Personnel from the Idaho Department of Fish and Game and the Nez Perce Tribe Fisheries identified the source of the leak as the hydroelectric generator on the main water supply pipeline for both hatcheries. The leaked fluid was determined to be Chevron Clarity Hydraulic Oil AW32, a type of hydraulic oil not expected to be harmful to aquatic organisms. An estimated 4.6 gallons were released before the leak was stopped.
Officials advised fishers along the North Fork Clearwater River to exercise caution, as rocks along the shore may be slippery due to the spill. While the Safety Data Sheet for the hydraulic oil states that skin contact is not expected to cause significant irritation, fishers are encouraged to wash exposed skin with soap and water after potential contact.
The hydropower generation unit at the hatcheries is owned and operated by the Idaho Water Resource Board, providing electricity to Clearwater County. The U.S. Fish and Wildlife Service, Idaho Department of Fish and Game, and the Nez Perce Tribe coordinate efforts to balance hydropower production with fish-rearing needs.
Following detection of the leak, staff from multiple agencies initiated containment and cleanup efforts at the hydroelectric plant, hatcheries, and the North Fork Clearwater River. Water samples were collected, and the young fish, which include more than 8 million steelhead and salmon smolts, were placed under observation. No immediate fish losses have been reported.
Officials continue to assess the cause of the leak while implementing conservation measures for federally listed fish in the area. The Lower Snake River Compensation Plan, a federally authorized fisheries mitigation program, supports hatchery operations to offset fish losses caused by the construction and operation of the four lower Snake River dams.
