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Dams Spill More Water to Aid Fish

by Mike Lee
Tri-City Herald, April 15, 2000

Hydrosystem operators planned to spill more water Friday over Columbia-Snake dams - the first full day of stepped-up efforts to keep fish out of turbines.

"We believe the tests will show the benefits ... more than outweigh the costs," said Perry Gruber, spokesman for the Bonneville Power Administration.

Now, river managers must be extra vigilant that the amount of "spill" doesn't harm fish by mixing too many dissolved gases into the rivers.

And they still must figure out how this week's relatively minor tweak of the system fits into the larger question of dam removal and salmon survival.

The BPA is tinkering with its spill program in response to direction from the National Marine Fisheries Service, which directs recovery efforts for federally protected salmon and steelhead in the river.

Spill is designed to propel fish over the dams instead of letting them navigate the deadly turbines. Some of the measures announced this week are experimental. Others are expected to be longer term.

Costs of the increased spill in terms of foregone power revenue are expected to be negligible because there's so much water in the rivers this time of year and power demands are relatively low compared with the peak of winter and summer, Gruber said.

Hopes are the coordinated spill plan increases fish passage by a little at each dam. It's directed toward dams where young fish traveling downstream fare the worst.

"This is one more small step to improve salmon survival," said Brian Brown, hydro operations director for NMFS.

Another major component of the effort to get juvenile fish downstream - barging them from the Snake River to the mouth of the Columbia - did not appear to be altered by this week's move.

Juvenile fish journeys to the ocean started this week, but when those fish return to the mouth of the Columbia in a few years, the landscape could be about to undergo a major transformation.

The Army Corps of Engineers is reviewing the benefits of taking out the four lower Snake River dams to boost fish passage and improve habitat.

Darryll Olsen, a Kennewick water policy analyst, said the spill program bodes well for the four Snake dams because it leaves three of them alone.

"They are going to keep the same program ... which means that NMFS does not have any plans to do dam breaching in the near-term," he said. "Otherwise, they would be monkeying around with this."

NMFS' Brown said those big-picture decisions still are being made as part of the Biological Opinion that is due in the next few months.

"The more difficult issues of potential dam breaching, increased spring and summer flows, improving water quality and the definition of the performance standards to recover threatened and endangered salmon are still ahead," he said.

At Bonneville Dam, the plan is to essentially double the standard daytime spill for about half the time. That will allow river managers to compare which spill level suits fish best.

At Lower Monumental Dam, full spill has been increased from 12 hours a day to 24 hours a day.

But at The Dalles Dam, the new plan calls for a substantial spill reduction because previous levels appear to have killed a disproportionate number of fish.

Olsen predicted the biggest benefits of the new spill regime would be at The Dalles. And he warned the federal plans may not work as hoped because of the delicate balance between spill and dissolved gases.

When spilled water crashes into the pools below dams, it captures atmospheric gases, which can harm fish if they reach too high of concentrations. Reaching the maximum gas level allowed would force a spill reduction.

"That's a lot of water they are putting over," Olsen said. "I wouldn't be surprised to see them run into gas problems."

Mike Lee
Dams Spill More Water to Aid Fish
Tri-City Herald, April 15, 2000

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