Grant County PUD Inaugurates $35 Million
By Christine Pratt
wenatcheeworld.com staff writer
MATTAWA — Young salmon on their first journey to the ocean no longer have to negotiate through the turbines to pass Wanapum Dam.
They can just take the slide.
Some 60 Grant County PUD officials and regional dignitaries inaugurated Wednesday the Columbia River dam's $35 million "fish slide" bypass.
Currently, an estimated 95 percent of young fish that pass through the dam survive, PUD spokesman Sarah Morford said. The new slide should increase survival rates even more, she said.
From downriver, the slide looks something like an elevator shaft, open on its face, that surrounds a gently sloping wall under a cascade of water.
The slide reduces the churning motion that traps harmful dissolved gas in the waters of the dam's tailrace. The gas is harmful for fish.
Fish returning upstream to spawn get around the dam via two fish ladders.
PUD spokeswoman Sarah Morford said construction began in June 2005 and ended last month.
The 10-turbine dam was originally designed with enough space for 10 additional turbines. These additional turbines were never added, because riverflows were insufficient, Morford said.
The new fish slide occupies two of these vacant turbine slots. Crews cut an 18½-foot hole into the side of the dam, and built the slide around it using some 100,000 truckloads (3,000 tons) of concrete.
Morford said PUD officials worked with researchers at the University of Iowa's College of Engineering to design and perfect the bypass. The college has miniature, working models of both PUD-administered dams, Wanapum and Priest Rapids.
The PUD operates both dams under a single, recently renewed federal license.
Morford said the slide design provided the best option for fish survival.
"Every hydro project is different," she said. "This slide has the best results for the configuration of Wanapum Dam."
Guests at Wednesday's inauguration endured ferocious wind gusts that partially upstaked a tent set up for the event, Morford said.
"This bypass is a great example of how efficiencies can be gained in energy generation while doing the right thing for fish," PUD General Manager Tim Culbertson told the crowd Wednesday, according to a partial transcript of a PUD video taken at the event.
"The Wanapum have always and will always be here to address our concerns and issues and work side by side with those here to improve the efficiencies ... and also to enhance the resources," Rex Buck, leader of the Wanapum People, said in the same PUD-supplied transcript.
Wanapum Dam is near the town of Desert Aire, south of Mattawa. It was built in 1959 and can generate as much as 1,038 megawatts of electricity.
Christine Pratt: 665-1173