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DWR director discusses efforts to safeguard California water systems from Quagga mussels

State water officials are taking actions to protect California’s State Water Project (SWP) — and other water resources – from an invasive species, the Quagga mussel. The mussel can clog water systems, alter food webs in ecosystems and damage boat engines. Thus far, Quagga mussels have not been found in the SWP, though two major Southern California water systems have tested positive for them.

“To combat the spread of Quagga mussels in California water systems, we urge boaters to wash their boats and drain all water upon leaving a reservoir and before trailering to launch in another lake,” said California Department of Water Resources (DWR) Director Lester Snow.

Monitoring of the SWP for the mussel is being expanded, as is outreach to boaters whose trailered vessels can spread the mollusks from lake to lake.

DWR has monitored for Quagga mussels since the invasive freshwater mollusks were first detected in California in January 2007 in Lake Havasu on the Colorado River. Subsequently, they were found in two Southern California water systems that use Colorado River water – the Metropolitan Water District of Southern California (MWD) and the San Diego County Water Authority.

MWD documented the mussels in March and again in July in its 242-mile Colorado River aqueduct, and also at Lake Mathews near Riverside and at Lake Skinner in Winchester, east of Temecula. On Aug. 21, the mussels were discovered in San Diego County, at San Vicente Reservoir near Lakeside.

Thus far, the mussels have not been found in the SWP, which draws its water from northern California watersheds. Environmental scientists are monitoring the system, one of the largest water and power systems in the United States.

Monitoring is done by state science professionals and also by a team of mussel experts from Portland State University, under contract to the state.

DWR is working with concerned water agencies to promote public awareness and is studying patterns of Quagga infestation in other water systems. DWR will sponsor an informational panel on Quagga mussels at the November 27-30 convention of the Association of California Water Agencies (ACWA) in Indian Wells. ACWA represents more than 450 water agencies that deliver more than 90 percent of California’s water.

Quagga boat warning cards were distributed at several major reservoirs during the Labor Day holiday weekend, including Diamond Valley Reservoir, Lake Skinner and San Vicente Reservoir in Southern California and at Lake Oroville in Butte County in Northern California.

Native to the Ukraine, Quagga mussels have become an expensive nuisance in the Great Lakes states of the Midwest. The mussels are thought to have reached the Great Lakes in ballast water from transoceanic vessels. They are believed to have entered the Colorado River system in boats trailered there from infested waters in the Midwest. Once the mussels establish themselves in a water body, they are difficult to eradicate.

All boaters and anyone who accesses freshwater aquatic environments should inspect all exposed surfaces to inhibit the spread of Quagga mussels, which feel like sandpaper to the touch. Boaters should thoroughly wash boat hulls, drain any water through the vessel’s hull plug and clean and dry any live-wells on the vessel. It is advised to keep boats dry and out of water for five days between different reservoir outings.

State agencies including DWR, the Department of Fish and Game, the Department of Boating and Waterways and the Department of Parks and Recreation are responding to the mussel challenge. More information about Quagga mussels is available at the Department of Fish and Game (DFG) Web site

A public toll-free number, 1-866-440-9530, has been established for boaters and anyone involved with activities on lakes and rivers seeking information on the invasive and destructive Quagga mussels. The toll-free number is available Monday through Friday, 8 a.m. to 5 p.m.

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