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Warm River Temperatures Pose Grave Threat to Salmon, Steelhead

by Jonathan Brinckman
The Oregonian, August 11, 2000

Scientists fear "a loss of epic proportions" in the Columbia and Snake rivers

Hot, dry summer weather has heated the Columbia and Snake rivers to temperatures unrecorded since 1992, raising fears of disaster for salmon and steelhead.

"Things look very bad this year," said Steve Pettit, a fisheries biologist with the Idaho Department of Fish and Game. "The conditions are pointing to a loss of epic proportions, unless we get a real break from Mother Nature."

No large fish kills have yet occurred. But biologists say that unless river temperatures cool, lots of the many adults returning this year could die before spawning. At the same time, the scientists warn, high temperatures may raise death rates of young, ocean-bound salmon now in the Columbia Basin.

The Snake and Columbia rivers, required by Oregon and Washington law to be kept at 68 degrees or below, have hovered at 70 degrees to 72 degrees for nearly a month. That's devastating for salmon and steelhead, which require clear, cold water.

The temperature at McNary Dam, for example, has not dropped below 68 degrees since July 14. Hourly temperature averages ranged from 72 degrees to 76 degrees on Tuesday, the last day complete records were available.

Relief is not in sight, said Kyle Martin, a hydrologist with the Columbia River Inter-Tribal Fish Commission, which represents four tribes with treaty rights to salmon. The jet stream is expected to stay in the Yukon and Alaska, shunting cool storms north of the Pacific Northwest.

The forecast, Martin said, is for temperatures in the mid-80s through September. "These reservoirs have become warm pools of death," he said.

For fish, short water temperature spikes are not harmful, biologists say. Salmon and steelhead can tolerate brief warm spells or can take measures -- such as ducking into cool tributary mouths -- to avoid hot water.

But long bouts of warmth can hurt fish by subjecting juveniles to long-term stress and raising their vulnerability to disease. Warm temperatures hurt adults by raising their metabolic rate, causing them to burn through energy reserves before they spawn. It can also cause them to hole up in cool areas, delaying their migration until too late in the year.

"It's the cumulative effect," said Bob Heinith, hydrosystem manager for the tribal fish commission. "In our minds the worst thing is how long this is lasting." Heinith said rivers have not been so hot for so long since 1992.

Biologists with the tribes and the states of Idaho, Montana and Oregon say that the federal government, which owns and operates dams on the Columbia and Snake rivers, is not doing enough to help cool waters.

Those biologists, for example, asked the National Marine Fisheries Service and the U.S. Army Corps of Engineers to hold water behind Dworshak Reservoir in Idaho so cooling water could be meted out in September. The agencies refused, calling it more important to release water in the summer to help young fall chinook reach the ocean.

Corps officials say they are doing what they can.

"It's really baking out there," said Doug Arndt, chief of the corps Northwest Division fish management office. "I don't like the fact that it's so darn hot, but given that it is, I think we're doing all we can to help out."

For example, said Arndt, the corps is releasing 47-degree water from Dworshak, which is cooling water from the upper Snake River that enters Eastern Washington at 73 degrees to 75 degrees.

Conservationists, state and federal biologists and biologists with the U.S. Environmental Protection Agency, however, say corps dams on the main Snake and Columbia rivers raise water temperatures by holding water while it is being warmed by the sun.

"To date, very little in the way of substantive measures to attain water quality standards for temperature has been brought," the EPA told the corps in a letter released last week.

"We've got to solve this problem," Mary Lou Soscia, the EPA's Columbia River Coordinator, said Thursday. "We've focused on developing ways to get fish past the dams. We need to spend time and effort on temperature and other water quality issues."

Jonathan Brinckman
Warm River Temperatures Pose Grave Threat to Salmon, Steelhead
The Oregonian, August 11, 2000

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