Posted: Sunday, January 16, 2011 2:59 PM
WENATCHEE, Wash. (AP) -- An innovative project at a Wenatchee fish hatchery is reusing water and raising healthier fish for release into the wild.
The project at the Eastbank Fish Hatchery also eases pressure on the aquifer system that is the regional water supply for about 67,800 people, according to officials with the Chelan County PUD.
The reuse system uses nearly 90 percent less water than traditional systems, said Joe Miller, the PUD's hatchery program. Most of the water used is filtered, reoxygenated, mixed with fresh water and then reintroduced into tanks.
Efforts to conserve water at the hatchery will prolong the region's right to draw from the aquifer and postpone the need to develop a costly new source of drinking water, the Wenatchee World reported.
The PUD-owned hatchery, near Lincoln Rock State Park in Douglas County, draws from the Eastbank Aquifer.
"The question is whether the aquifer can handle the draw for everyone," said Greg Brizendine, manager of the East Wenatchee Water District.
The most recent estimates show that the region's water right to draw from the aquifer could be depleted by 2025, based on an estimated population growth of 1 percent per year. The Chelan PUD, the city of Wenatchee and the East Wenatchee Water District jointly operate the metro area's regional water supply, fueled by the Eastbank Aquifer.
In 2008, the PUD launched an experiment to see if methods used by the aquaculture industry could be used for raising salmon for release into the wild.
At the Eastbank facility, which the state Department of Fish and Wildlife manages for the PUD, water constantly flows in a gentle, circular current in two circular fiberglass tanks. Fish droppings and uneaten food are collected over a central drain at the center of the tanks' concave bottoms and remove with a quick flush before they break down to dirty the water.
The system allows more fish to be raised in the same amount of water for overall water savings of nearly 90 percent, Miller said.
One surprising outcome has been that fish are "fitter" and more eager to migrate to the ocean, officials said.
The round tanks serve as "fish treadmills." Their circular flow keeps baby fish constantly swimming against the current in water that has a consistent temperature and oxygen levels.
Miller said the 25,000 steelhead smolts from the Chiwawa facility migrated nearly a week earlier than raceway-reared smolts. Their survival rate past McNary Dam, 200 miles and four dams downstream, increased from 51 percent to 80 percent.
Information from: The Wenatchee World, http://www.wenatcheeworld.com
Copyright 2011 The AP.