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Snake River Dam Operation

National Wildlife Federation et al. v. United States Army Corps of Engineers, 99-442-FR (D. Or.)

The Snake River is the largest tributary of the Columbia River. Up to 45% of all Columbia Basin chinook salmon once hatched in the Snake River's tributaries. Millions of juvenile fish are carried by annual spring floods 600 miles to the Pacific Ocean; these same fish swim upstream as adults a year or two later to spawn and die, starting the cycle anew.

The U.S. Army Corps of Engineers operates the four lower Snake River dams as part of the Federal Columbia River Power System. From the confluence of the Columbia and Snake River looking upstream, the four lower Snake dams are Ice Harbor, completed in 1961, Lower Monumental, completed in 1969, Little Goose, completed in 1970, and Lower Granite, completed in 1975.

In general, the reservoirs behind dams slow water velocity and increase the river's cross section, exposing more water to heating by the sun for longer periods -- increasing water temperatures and keeping those temperatures higher for longer periods of time. Releasing water from reservoirs behind dams causes increases in the level of dissolved gas in river water instantaneously (higher spikes in dissolved gas levels) and cumulatively (longer duration of high dissolved gas levels). Both of these effects can be reduced or eliminated by changes to dam operations or structures.

Because both high temperatures and elevated levels of dissolved gas are harmful or lethal to salmon and steelhead, the State of Washington has enacted protective water quality standards.

In 1997, the Environmental Protection Agency and the States of Washington and Oregon put the Army Corps on notice that its operations of the four lower Snake River dams were violating water quality standards for temperature and dissolved gas.

Modeling done by EPA shows that the four lower Snake River dams cause temperatures in the river to exceed the 20 degree Celsius water quality standard set by the State of Washington.

The Army Corps admits that its operations of the dams violate the water quality standard for dissolved gas of 110% of saturation; at times, its actions also violate even higher dissolved gas limits granted by the State of Washington as waivers of the 110% standard.

National Wildlife Federation, Sierra Club, Idaho Rivers United, American Rivers, Pacific Coast Federation of Fishermen's Associations, Institute for Fisheries Resources, Washington Wildlife Federation, and Idaho Wildlife Federation filed a lawsuit challenging the Army Corps' violations of the Clean Water Act. The Nez Perce Tribe joined the conservation and fishing groups as a plaintiff-intervenor, and the State of Oregon supported the lawsuit's claims as amicus curiae.

On March 24, 2000, the federal district court ruled that the Army Corps' operation of the four lower Snake River dams must comply with water quality standards pursuant to the Clean Water Act, noting that "[t]here is evidence in these documents that the agency actions regarding the operation of the dams directly affect the alleged violations of water quality standards with regard to temperature and total dissolved gas on the Lower Snake River." The court ordered both sides to review the written record underlying the agency actions and present that and other evidence to the court at a hearing held February 7, 2001. On February 16th the court ruled that the federal government's operation of four dams on the lower Snake River violates the Clean Water Act, and the Court ordered the U.S. Army Corps of Engineers to produce a decision that complies with the Clean Water Act to protect threatened and endangered salmon and steelhead within 60 days.