Idaho Power Company will spill billions of gallons of water from Brownlee Reservoir over the next several weeks to give juvenile chinook salmon a leg up as they migrate down the Snake and Columbia rivers to the Pacific Ocean.

Perhaps andquot;a fin upandquot; is the proper term, seeing as how salmon lack legs.

The water is supposed to help propel the little salmon through the gantlet of sluggish reservoirs behind four federal dams on the lower Snake River: Lower Granite, Lower Monument, Little Goose and Ice Harbor.

Although Brownlee will shrink during the so-called andquot;fish flush,andquot; the reservoir's major boat ramps should remain usable at least through early August, said Roger Fuhrman, Idaho Power's director of water management.

Brownlee will stay at its current level, about five feet below full, through July 6.

andquot;Not quite a full pool on the Fourth of July, but we'll be pretty close,andquot; Fuhrman said.

Idaho Power will dump water from Brownlee throughout July. As summer progresses and less water flows into the reservoir from the Snake River and its tributaries, the reservoir level will continue to recede.

Fuhrman projects Brownlee will drop to 18 feet below full by Aug. 7. Boat ramps in Baker County remain useable at that elevation.

The fish flush will be finished by then, but the reservoir could drop even more later in the summer depending on the weather.

During heat waves, Idaho Power has to divert more water through Brownlee Dam's power-producing turbines to feed tens of thousands of air-conditioners.

History of andquot;fish flushesandquot;

For several years after 1992, when the federal government listed runs of Snake River salmon and steelhead as threatened or endangered, Idaho Power agreed to release water from Brownlee to help the fish.

Biologists say that the faster salmon and steelhead can swim through the series of reservoirs the more likely they are to survive the journey. Reservoirs are less than ideal places for ocean-going fish because the water's often warmer than the fish prefer, and predators such as the northern pikeminnow congregate in the reservoirs.

In some years during the 1990s, Idaho Power started the andquot;fish flushandquot; as early as June.

The flushes, combined with deep snowpacks that forced Idaho Power to dramatically lower Brownlee in spring to make room for runoff, left many of Brownlee's boat ramps stranded above the water for months.

Those severe fluctuations in the water level also pared the reservoir's populations of crappie, bass and other fish that had previously lured thousands of anglers to Brownlee.

The reservoir's reputation as a hot fishing hole had cooled by the mid 1990s, and businesses in towns near the reservoir, including Richland and Huntington, suffered as anglers hauled their boats to other bodies of water.

The Bonneville Power Administration compensated Idaho Power for fish flushes in the 1990s by giving the company electricity in amounts equal to the power the company could have produced had it run the water past Brownlee Dam's turbines rather than passing it through the spillways.

That compensation deal expired about the turn of the century, though, and when it did Idaho Power stopped dumping water for salmon.

In 2003, however, two conservation groups, American Rivers and Idaho Rivers United, sued the Federal Energy Regulatory Commission, which oversees the federal license that governs how Idaho Power operates Brownlee, Oxbow and Hells Canyon dams.

The groups alleged FERC had failed to protect salmon and steelhead because the agency didn't require Idaho Power to participate in fish flushes.

In 2004 Idaho Power, which has applied to FERC for a new license (the current license expired in 2005; the company is operating under the terms of its former license), agreed to resume fish flushes as part of an andquot;interim operating agreementandquot; with FERC, Native American tribes and the two groups that sued FERC.

Idaho Power agreed to release 237,000 acre-feet of water from Brownlee.

To put that figure into perspective, it's slightly more than three times as much water as Phillips Reservoir, near Baker City, holds when it's full.