SAN FRANCISCO – The U.S. Army Corps of Engineers San Francisco District has prepared a Draft Coyote Valley Dam-Lake Mendocino Water Control Manual Update Environmental Assessment (EA) Report. On July 17, 2025, the District released a letter announcing the availability of this Draft EA for public review and comment. The comment period is scheduled to end on Aug. 16, 2025. The report and appendices can be downloaded at: https://www.spn.usace.army.mil/Missions/Environmental/
Written comments may be emailed to: CESPN-CVD-WCM-Update@usace.army.mil
More about the report
Current operations of Coyote Valley Dam and Lake Mendocino are governed by the existing Water Control Manual (WCM) which was revised in 1986 and last updated in 2011 without the benefit of modern weather and streamflow forecasting information. The purpose of the proposed action is to update the CVD-Lake Mendocino WCM to allow discretionary encroachment into Flood Control Space based on the 5-day deterministic streamflow forecasts provided by the National Weather Service as per Lake Mendocino Forecast-Informed Reservoir Operations (FIRO) procedures that have been vetted and tried through a series of USACE-approved major deviations during Water Years 2019, 2020 and 2021-2026. The encroachment would provide water storage of up to 11,650 acre-feet into the flood control space, and USACE reservoir operators retain full operational control and authority.