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Planned dam bypass to aid salmon, trout

Tim Omarzu

A hydroelectric generator at Englebright Dam has had a nasty habit of shutting down this time of year, causing the Yuba River to suddenly drop a few feet.

That can potentially harm the Yuba’s chinook salmon and steelhead trout – both listed as threatened on the endangered species list – by stranding them or leaving their redds, or nests, high and dry.

It’s been two years since the generator abruptly shut down. But the problem should be solved permanently because the Yuba County Water Agency plans in 2004 to install a $6 million “bypass valve” which would keep water flowing below the dam when the hydroelectric generator fails.

“We’re real excited,” said Steve Onken, YCWA power systems manager. The bypass valve that the agency plans to install is “actually a very simple system and it’s foolproof.”

Currently, when something goes wrong with a power transmission line, the turbine-powered generator must be shut down. Otherwise, it would burn up.

Curt Aikens, the agency’s administrator engineer, compared it to flooring a car’s accelerator and then having someone lift up the rear bumper so the wheels aren’t touching the ground.

“Your engine would blow. The same thing happens with the turbine,” Aikens explained.

The bypass will allow water to be routed around the turbine when there’s a problem, keeping the flow constant in the Yuba River.

The YCWA will fund the bypass with $1.5 million of its own money and a $4.3 million grant from Calfed, the Bay Delta restoration effort. The grant was awarded earlier this year.

Nevada County fly fisherman Rick Aeschliman was on the river two years ago when a shutdown suddenly caused the river to drop 4 to 6 feet, he said.

“I’m glad they’re going to fix up the dam … if they can keep the water from dropping suddenly, that’s wonderful,” he said.

A string of past shutdowns prompted the South Yuba River Citizens League and the Sacramento-based Friends of the River to file a complaint in 1998 with federal regulators, charging that sudden drops in the river’s level could hurt spawning salmon and steelhead trout.

Now, Janet Cohen, SYRCL’s executive director said, “We’re delighted, this will really help the fish.”

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