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Biologist challenges Klamath models

Researchers don wet suits to measure temperatures

Tam Moore
Capital Press Staff Writer

YREKA - The National Research Council scientific committee studying data underpinning government-dictated flows for the Klamath River could take the role of myth-busters - if they act on expert testimony given here last week.

In almost one-two order, a fisheries biologist and a consulting engineer challenged basic assumptions in the Hardy Phase II flow study finally delivered to the U.S. Department of Interior two months ago. It's unclear how challenges to basic assumptions might influence future management of water shared by irrigators, fish and recreational water users.

Mike Belchik, senior biologist for the downriver Yurok Tribe and leader of a massive sampling of summer temperatures below the dam that blocks salmon migration, said the only significant downstream cold-water refuges for young fish are where tributary streams enter the main Klamath. Tributary flow, he said, is strong enough to preserve those pockets of cold water.

Belchik's team put on wet suits and swam the 60 miles below Iron Gate Dam, carrying sensitive temperature probes with them.

"Do you think greater flows will wipe out refugia?" a committee member asked.

"We think not," Belchik said.

Mike Deas, a veteran watershed consulting engineer, told the committee that water quality - from the nutrient-rich Upper Klamath Lake - is a far greater danger to fish survival than elevated summer stream temperatures.

"What that means is a lot of algae" below the lake, Deas said, in concentrations that make reaches of the river near Keno, Ore., "dead zones" with no oxygen for fish.

The NRC committee is charged by Interior with giving peer review to both the Hardy report and a U.S. Bureau of Reclamation study reconstructing natural flows that existed before the 1905 project shifting over 200,000 acres from lakes and wetlands to croplands and pasture.

Will Graf, the University of South Carolina geography professor who heads the 13-member panel, said one more physical committee meeting - to get facts on how Reclamation hydrologists built their natural flow model - will be held in Klamath Falls, Ore., in January. Graf hopes the draft report will be out by early summer 2007.

Utah State University hydrologist Thomas Hardy, who has been modeling flows needed for salmon, told the review committee he limited summertime downstream discharge. The theory is that lesser flows avoid breaking up downstream patches of cold water sought by juvenile salmon making their way to the ocean.

Klamath coho salmon are under Endangered Species Act protection. The native run of Klamath chinook dropped so low that commercial ocean fishing was all but banned this year off 700 miles of California and Oregon coastline.

Water quality is "an under appreciated" Klamath problem, Deas said. He pointed out that total output of the 10 million acre watershed shared by California and Oregon varies widely from year to year. In 2000, about 12 million acre feet flowed into the Pacific Ocean, but in droughty 2001, discharge dropped to 6.2 MAF.

Despite that wide fluctuation in runoff from winter precipitation, the system has low runoff every summer, dropping flows and making them warmer as sun-heated water from hydroelectric dam reservoirs makes its way downstream. Present summer flows are dictated by a court order aimed at aiding coho. Coho juveniles remain in the river for one year before heading to sea. Prolonged water temperatures over 68 degrees F are fatal.

Hardy said he didn't put water quality in his study because both California and Oregon are setting total maximum daily loads of pollutants for the Klamath and its major tributaries.

Water temperature, he said, appears a limiting factor to the various life stages of migrating fish. He built changes in base flow of the river around when fish are in various reaches of the river.

The issue over summer cold-water refuges is more complex. Over the years some fish biologists have argued that greater summer flows help move fish downstream faster - through those long stretches of warm water. Others point out that disease and pests attack fish, sometimes resulting in massive kills such as the much-publicized lower river die-off in late August 2002. Flows were so low at the time that observers said migrating chinook were trapped about 18 miles from the river's mouth.

The U.S. Geologic Survey, Interior's science think tank, launched a detailed study of available fish habitat. Under contract to California Department of Fish and Game, the scientists are looking in detail at the 47 miles immediately downstream from Iron Gate Dam. Tim Hardin, the USGS team leader, told the committee his work will be translated into computer models that help scientists understand traits of habitat favored by different fish.

Tam Moore is based in Medford, Ore. His e-mail address is tmoore@capitalpress.com.


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