By Kathleen Wong
Cold water, essential for the life cycle of Chinook salmon, is all too often in short supply along the Sacramento River. A primary cause: California’s massive water conveyance system, using reservoirs, dams, and hydroelectric plants to divert water and deliver power to farms and cities. “When we started releasing water in spring, we let cold water out too early. None was left by fall, when salmon really needed it,” says USBR hydraulic engineer Tracy Vermeyen. Two clever innovations have been implemented to conserve cold water into the autumn. First: A 300 foot tall, 250 foot wide “adjustable straw” possessing a series of intake gates enables power plant operators to draw water from behind the dam at three different depths. Second: A 40 foot tall rubber sheet. The curtain blocks all but the deep, cold water from traveling past. “It’s a clever idea and it’s been fun to work on all these years,” says Vermeyen.