Lake Sonoma at 84 Percent of Capacity

The Russian River water supply condition changed from “normal” to “dry” this week  under the Sonoma County Water Agency’s water rights permits and State Water Resource Control Board Decision 1610.

According to Decision 1610, which was issued in 1986, a water year is declared normal, dry, or critical on the first of each month between January and June based on cumulative inflow into Lake Pillsbury, located in Lake County on the Eel River.

This “dry” designation means the water agency can reduce flows in the Russian River to preserve water storage in Lake Mendocino so there is enough for all water users and for release in the fall to support the migration of Russian River Chinook Salmon, listed as threatened on the Federal Endangered Species List. 

Flows may be reduced as shown below due to the dry year designation: 

• Upper Russian River, between Lake Mendocino and the confluence of Dry Creek and the Russian River near Healdsburg.
• Lower Russian River, between the confluence of Dry Creek and the Russian River to the Pacific Ocean.
• Dry Creek, between Lake Sonoma and the confluence of Dry Creek and the Russian River.

The Water Agency’s two water supply reservoirs, Lake Sonoma and Lake Mendocino, continue to provide a reliable, secure source of drinking water for more than 600,000 residents in portions of Sonoma and Marin counties despite this year’s dry weather, officials said. 

Reservoir water supply levels as of Feb. 1 at Lake Sonoma was 84 percent of water supply capacity. Lake Mendocino was at 89 percent of water supply capacity.

“The reduced in-stream flow requirements set the floor for how low the Russian River may be allowed to flow in order to ensure there is enough water stored in Lake Sonoma and Lake Mendocino for multiple uses, including the release of water for the fall migration of Chinook salmon,” said Assistant General Manager of Operations Pam Jeane. 

“Fortunately, despite the dry weather and the dry year designation, water storage in Lake Sonoma and Lake Mendocino remains in fair condition," Jeane said. "Rain or shine, we ask that our community continue to use water efficiently -- there is never enough water to waste.”