State Requirements force Sonoma County to Waste Water

Even though water storage in Lake Mendocino is only at 59% of capacity, on March 12 the Sonoma County Water Agency began releasing more water – an additional 25 cubic feet per second - from Lake Mendocino in order to comply with state-mandated Russian River instream flow requirements. Drying tributaries are sending upper Russian River flows plummeting to near state-mandated levels – 150 cfs in the upper Russian River and 125 cfs in the lower Russian River.

“We are mandated to release water we don’t have from Lake Mendocino,” said Paul Kelley, chair, SCWA Board of Directors and Sonoma County Board of Supervisors. “We are facing both a natural and regulatory drought.”

The concern about Lake Mendocino revolves around the need to have adequate water in storage for the summer and fall for all water uses in the system. These uses include municipal water supply for portions of Mendocino and Sonoma counties, water for protected coho salmon, Chinook salmon and steelhead under federal and state endangered species laws, water for recreation at Lake Mendocino and along the Russian River, and agricultural water supply. Additionally, SCWA is concerned about having to release additional water to satisfy agricultural frost protection needs in March and April. Without additional releases, frost protection diversions could harm juvenile salmonids.

Water flows into Lake Mendocino from PG&E’s Potter Valley Project have been reduced by thirty-three percent due to a 2004 decision by the Federal Energy Regulatory Commission. The Potter Valley Project diverts Eel River water through a Mendocino County powerhouse owned and operated by PG&E into the upper Russian River Basin, and is the source of most of the summer flow in the East Branch Russian River to Lake Mendocino. This 2004 FERC decision limited the amount of water PG&E can divert from the Eel River for power production. Historically, flows through the Potter Valley Project into the East Branch Russian River would have been in excess of 300 cfs this time of year, but are currently less than 50 cfs.

Despite the continued lack of water in Lake Mendocino, the current water year became “normal” based on the requirements in SCWA’s water rights permits and State Water Resources Control Board Decision 1610. The determination of a normal, dry or critically dry year is defined by Decision 1610. Dry year conditions were in effect for the period from February 1 to February 28 and minimum flow requirements were reduced to 75 cfs and 85 cfs in the upper and lower Russian River, respectively.

SCWA is preparing a Temporary Urgency Change Petition for submittal to the State Water Resources Control Board to reduce Russian River instream flow requirements this summer. The details of the petition will not be determined until April 1, the next time the water year type (normal, dry, or critically dry) is declared. There will likely be a hearing by the State Water Board to consider the petition within a few months of its submittal.

As of March 12 Lake Mendocino’s water storage level still remains low – only 59 percent of capacity – compared to 95 percent last year.

Sonoma County Water Agency provides water supply, flood protection and sanitation services for portions of Sonoma and Marin counties. Visit us on the Web at www.sonomacountywater.org.