From Whiskeytown Lake to Sacramento River: New curtain will keep water cool
Project prevents warmer flow, protects salmon habitat
Dylan Darling
Redding.com
05/09/2011
There's a massive new curtain being installed at Whiskeytown Lake to cool water released into the Sacramento River for the sake of salmon eggs.
Construction workers on contract with the Bureau of Reclamation are busy setting up the curtain, which is nearly a half-mile long and drops into the lake's water as much as 110 feet, said Bob Gee, a mechanical engineer for the bureau. He said the $3-million project should be completed by the end of the month.
The old $2-million rubber curtain, installed in 1993, already is gone, Gee said.
"It had a lot of holes in it," he said.
The holes were caused by the curtain rubbing against chains linking buoys holding the top of the curtain to anchors on the lake bottom, Gee said.
"It just had deteriorated," said Brian Person, manager for the bureau's Northern California Area Office at Shasta Dam. "So it was time for a replacement."
Bureau engineers redesigned this curtain and are using a different material to try to avoid the problem. The old curtain was made out of Hypalon, a synthetic rubber also used in rafts and roofing. The new curtain is made of reinforced polypropylene, a thick fabric also used as a liner for landfills, waste ponds and fish hatcheries.
The new 2,400-foot-long curtain should last at least 15 years, Gee said. The curtain blocks warm water from the lake's surface from going into a tunnel leading to the Sacramento River. There will be about a 30-foot gap between the bottom of the curtain and the bottom of the lake, allowing cold water to flow into the tunnel.
The replacement began in November, when workers from Erick Ammon Inc. of Anderson started pulling up the old curtain, he said. Along with replacing the curtain the workers repaired and repainted the string of 120 buoys that holds it up. They are set to attach 120 weights, weighing 1,000 pounds each, as they unfurl the new curtain this month.
Known to most people in the north state as a place to swim or boat, Whiskeytown Lake is part of a half-century-old system of dams and tunnels that carries water diverted from the Trinity River to the Sacramento River.
