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Research aids Northwest salmon

BY GRACE SAVIDES | APRIL 27, 2010 7:30 AM

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Three scale models of hydroelectric dams designed by University of Iowa researchers are good news for salmon — and those who enjoy eating them.

A team of researchers from the Iowa Institute of Hydraulic Research-Hydroscience & Engineering are trying to solve problems posed by hydroelectric dams to salmon. The dams can hinder the fish when they try to travel upstream to mate and lay eggs where they were born.

The UI has been on the forefront of fish-passage technology for the last three decades. The hydroscience and engineering department recently renewed its contract with Public Utility District No. 2 of Grant County, Wash., which will provide $15 million to continue research into improvements to hydroelectric dams in the Pacific Northwest.

In the Coralville-based James Street Laboratory on Monday morning, Larry Weber, director of the UI’s hydroscience labs, noted the UI and the Washington public-works company have been collaborating since 1983.

“Because of our long history, we created a lot of specialized knowledge no one else had,” he said.

Though the building where Weber and his colleagues work resembles a warehouse from the outside, the interior looks more like a cross between an aquarium and a waterpark — full of rushing water and complex machinery.



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Scientists originally thought salmon could swim through the dams’ turbines, but later discovered those mechanisms could leave fish disoriented, easy targets for predators, Weber said.

The water from the dams can also trap nitrogen from the air in the water. Though this only happens occasionally, the excess nitrogen can cause gas-bubble disease, sickening or killing the salmon.

According to a report by the Pacific States Marine Fisheries Commission and the Oregon Fisheries Congress, dams in the Upper Columbia River Basin are responsible for 70 to 96 percent of the downstream migrating young fish deaths and approximately 40 percent of deaths in upstream migrating adults.

Past UI research has aided salmon during a different part of their life cycle — when they travel upstream. Now, they’re looking to help juvenile salmon swim downstream through the dams to the sea.

Their solution? The Juvenile Fish Bypass.

The bypasses, designed by UI officials, are built into pre-existing structures of dams and can be opened to allow salmon an easy exit that doesn’t leave them dazed. The bypasses also keep them at the surface as they exit, lessening the effect of any excess nitrogen.

“The whole purpose of this is to increase the survival of the fish,” said Troy Lyons, a staff engineer for hydraulic institute.

Officials only open the Juvenile Fish Bypasses during the time of the year when the salmon, who are often tracked by radio tags, are near the dam.

The survival rate for salmon tracked through a bypass has been 100 percent.

Andy Craig, a staff engineer for the institute, said engineers weren’t sure how the dams would affect fish when they were constructed, and they are now looking to alter them to be ecologically responsible.

The institute’s contract with the Washington public-utility district, which was renewed in January, will extend for the next five years. Since 1983, the fish-passage program has generated more than $40 million in research funding.


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