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Panel Favors Steady Dam Flow over High Volumes

by Erik Robinson, Staff Writer
The Columbian, February 20, 2003

PORTLAND -- A key scientific advisory panel is questioning the value of boosting the flow of the Columbia River to help migrating juvenile salmon, an article of faith among biologists for more than two decades.

The Independent Scientific Advisory Board, which advises river managers in the region, cited scientific uncertainty over the value of dumping water out of huge upstream reservoirs to "flush" juvenile salmon toward the ocean. The panel instead suggested a more sure-fire method of improving salmon survival leveling out the fluctuation of water pulsing through dams to meet daily peaks in demand for electricity.

Scientists Charles Coutant and Richard Whitney presented the ISAB's review Wednesday morning to members of the Northwest Power Planning Council in downtown Portland. Given that flow-augmentation has been a bedrock principle of managing the river since 1982, Whitney acknowledged the scientists' findings would create a stir. "It's an eye-blinker, definitely," he said after Wednesday's presentation.

Because salmon and steelhead have evolved to take advantage of the big burst of spring and summer snowmelt, federal dam managers have boosted flow to provide a modest simulation of the pre-dam environment.

Three months ago, the power planning council drew fire from conservation and tribal groups by suggesting federal dam managers curtail the amount of water dedicated to boosting springtime flow for salmon. In an effort to clarify the benefits of flow augmentation, the four-state council asked its scientific advisory board to review scientific literature and studies.

Conservation representatives said they're frustrated the panel suggested more studies.

"We continue to ask for more money and more science to inform us that fish need water," said Liz Hamilton, executive director of the Northwest Sportfishing Industry Association. "That's what's frustrating to us."

Costly water

Two years ago, water became more precious than ever.

Power prices spiked to unprecedented heights, and the region was in the throes of a drought. The Bonneville Power Administration seriously curtailed the amount of flow it was supposed to provide for fish so it could generate more electricity. In the end, it provided only about 15 percent of the minimum recommended by the National Marine Fisheries Service to help juvenile salmon migrate to the ocean.

The BPA estimated the value of that water to be a staggering $ 1.4 billion. That figure counts revenue that could have been generated selling surplus power to California and costs that could have been avoided by having to buy electricity in the hyperinflated wholesale market.

Conservation groups point out that argument could just as easily be attributed to water dedicated to flood control, irrigation or navigation.

Even so, the ISAB review adds to a rising chorus of industry voices that have long questioned the value of dedicating water for fish, especially during years when water is scarce.

"Faith isn't good enough any more," said Scott Corwin, vice president of the Pacific Northwest Generating Cooperative. "We ought to be able to show what the return is on our investments. If there's no correlation between incremental flow and juvenile survival, then maybe we should look at other ways of doing things."

Migratory benefits

But the scientists point out that evidence points to a clear increase in survival during years when migrating salmon ride out on a big natural flow of water during the spring and summer migration season. They also pointed to a statistical "breakpoint" in which the survival of yearling chinook and steelhead smolts in the lower Snake River clearly improves when the average daily flow out of Lower Granite Dam tops 100,000 cubic feet per second.

Given that finding, federal biologists say they are unlikely to back away from flow augmentation.

"You see benefits, so why change it?" said Paul Wagner, a biologist for the National Marine Fisheries Service in Portland.

The independent scientists, however, questioned whether there's any benefit at all from artificially boosting flows when the natural runoff is already well above the statistical breakpoint. At levels below or near the breakpoint, they suggest dam managers could do more to improve survival of migrating salmon by moderating daily pulses of high and low discharges.

"You could add enough water to get you over that hump, but that hump isn't all that clear," Coutant said. "Getting a stable flow is much more manageable."

But that might be easier said than done.

As people turn up their toasters in the morning, dam managers boost the flow coming through turbines.

Coutant, senior resource ecologist at the Oak Ridge National Laboratory in Tennessee, said hourly bursts in flow at the dams may be causing an effect in reservoirs similar to water sloshing back and forth in a bathtub. Sensing a temporary reverse current, migrating fish may be delayed by swimming in the wrong direction.

Coutant said this "sloshing effect" may overwhelm any perceived benefit releasing water from Dworshak or Brownlee reservoirs, the two major storage reservoirs in the Snake system.

"The net result looks like an increase in chaos and confusion, rather than helping them much," Coutant said.

Erik Robinson, Staff Writer
Panel Favors Steady Dam Flow over High Volumes
The Columbian, February 20, 2003

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