Water-Saving at Dams May Hurt Northwest Salmon Run

SAN FRANCISCO —  Federal agencies, citing a severe drought in the Northwest and concerns over power supplies, have dropped plans to spill water at major dams in the region, a move that will hamper the downstream migration of young salmon to the Pacific Ocean.

The Bonneville Power Administration, the federal agency that markets electricity from huge dams along the Columbia and Snake rivers, said the move was necessary to maintain the reliability of the electric system serving the West.

“This was a very painful, difficult decision, but the drought has so depleted water supplies that the reliability of the region’s electricity system is in peril,” acting administrator Steve Wright said late Tuesday.

The power agency, based in Portland, Ore., said the hydroelectric system will not spill water at the dams for at least two weeks under emergency provisions that override biologists’ recommended programs for increasing endangered salmon stocks.

Running water through the spillways helps young salmon swim over the top of the dams and avoid a far riskier run downstream through the spinning blades of the dams’ turbines.

But using spillways releases water that could be needed this summer for power generation.

The agency said the water saved by not spilling is enough to generate 1,000 megawatts.

The National Marine Fisheries Service estimated that dropping the spill program will decrease survival rates by up to 15% on the Columbia River but only up to 2% on the Snake, depending on the availability of trucks and barges to safely carry young fish around the dams’ turbines.

Officials said the drought, after one of the driest winters in 70 years, is expected to cut the flow of water through the lower Columbia River by half this summer.