BPA to Reduce Water it Spills to Help Salmonby Erik Robinson, Staff Writer
The Columbian, June 9, 2004
Federal dam managers will cut short the amount of water spilled away from Columbia River dam turbines this summer, instead using the water to generate electricity to be sold in California.
Conservation groups condemned Tuesday's announcement, while business groups said it doesn't go far enough.
Biologists generally consider the practice of dumping water over spillways safer than shooting fish through turbines, where they might clang off the turbine blades or suffer an effect similar to the bends in deep-sea divers.
But the practice saps the dams' ability to generate electricity.
Bonneville Power Administration chief Steve Wright expects the proposal to generate an extra $20 million to $31 million, enough to shave 1 or 2 percentage points from wholesale rates charged in the Northwest. Officials say they'll offset the harm to endangered Snake River fall chinook in August by paying Idaho Power Co. to drain 100,000 acre feet of water worth $4 million out of Hells Canyon in July.
Bush administration officials said they expect the water from Brownlee reservoir in Hells Canyon will improve fish survival in July, offsetting the loss of roughly 1,000 smolts in August.
"Those are very small numbers, and it's unlikely a change that small would have any effect on the genetic diversity of a run that starts with 1 million juveniles," said Bob Lohn, regional administrator of the National Marine Fisheries Service.
State and tribal biologists aren't so sure.
Bill Tweit, Columbia River policy director for the Washington Department of Fish and Wildlife, said those few late-emerging Snake River fall chinook smolts have survived at a better rate in some years than smolts in the peak of the run. State officials want to protect the genetic traits carried by late-emerging smolts.
"These fish are still clearly evolving to adapt to a new ecosystem, and the tails of your run are sometimes where the new adaptations come from," Tweit said.
The federally funded Fish Passage Center in Portland echoes the state's concern.
"Elimination of summer spill could be especially detrimental to fall chinook during low flow years, when the sub-yearling migration is shifted later into the summer," the center's director, Michele DeHart, wrote in an April 6 memo.
The total Columbia River flow for this year is projected to be only 78 percent of normal.
Although dam managers point out that 90 percent of migrating smolts are scooped up and barged below Bonneville Dam during August, DeHart's memo presented evidence that argued for spilling more water, not less. She pointed to evidence suggesting fall chinook smolts that migrated through the river on their own sliding over the spillway at McNary Dam returned as adults at a higher rate than those hauled aboard trucks and barges.
"This is a big flaw in their analysis," DeHart said.
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