The Sonoma County Water Agency manages the water supply storage within Lake Mendocino and Lake Sonoma. Lake Mendocino relies on year-to-year rainfall to fill and water diverted from the Potter Valley Project, which has been reduced by more than half. Lake Mendocino is a key drinking water source for the cities of Ukiah, Healdsburg, Cloverdale and Hopland, and also provides water to the Water Agency’s Russian River water supply system. Water releases from Lake Mendocino support flows in the Russian River for the threatened Chinook salmon and steelhead trout during the fall and winter seasons. Lake Sonoma is about four times larger than Lake Mendocino and can provide multiple years of water supply under the current drought. Lake Sonoma provides a majority of the Water Agency’s service area with drinking water.