Hydraulic fluid leak contained at Clearwater, Dworshak hatcheries

OROFINO — A hydraulic fuel leak that threatened millions of steelhead and salmon smolts was quickly contained at two Idaho hatcheries.

In the early morning hours of Feb. 26, Idaho Department of Fish and Game staff at the Clearwater Fish Hatchery and Nez Perce Tribe Fisheries staff at the Dworshak National Fish Hatchery noticed an oily sheen in the fish-rearing raceways, a press release said.

Those raceways hold over 6 million young steelhead and salmon smolts that are the future for the Clearwater River Basin under the U.S. Fish and Wildlife Service’s Lower Snake River Compensation Plan. An additional 2 million juvenile steelhead were reared in a U.S. Army Corps of Engineers-funded mitigation program at the Dworshak NFH, the release said.

"Hatchery staff quickly identified that the fluid was leaking from the hydroelectric generator on the main water supply pipeline for both hatcheries," the release said. "The hydropower generation unit is owned and operated by the Idaho Water Resource Board. The fluid has been identified as a type of hydraulic oil that is not expected to be harmful to aquatic organisms."

The leak was quickly stopped; an estimated 4.6 gallons had left the facility.

The fluid involved in the spill was identified as Chevron Clarity Hydraulic Oil AW32l. The Safety Data Sheet for Chevron Clarity Hydraulic Oil AW32 states that skin contact is not expected to cause prolonged or significant irritation.

The SDS also states that ingestion and eye exposure aren’t expected to be harmful. The hydropower generation unit at the fish hatcheries produces significant amounts of power for Clearwater County by harnessing the power of 40,000 gallons per minute of water needed to grow fish at the hatcheries. 

After the leak was detected, staff notified the agencies involved and began deploying available spill containment at the hydroelectric plant, the fish hatcheries and in the North Fork of the Clearwater River. 

Additional resources and staff were deployed to contain and clean up the hydraulic fluid and diagnose the cause of the leak. In addition, water samples were taken and the young fish were put under constant observation.

"Due to quick responses, no immediate fish losses have been observed, officials said," the release said. 

Biologists are working to implement conservation measures for federally listed fish in the area.