Groveland, CA…The San Francisco Public Utilities Commission (SFPUC) will begin repair work on the valvehouse at Cherry Lake in the fall. Public access to the lake will be restricted from September 5th until the work has been completed. Last winter, one of the four high flow release valves experienced a mechanical failure. Additionally, another two valves are scheduled for replacement. Valve repair and replacement is essential for safe dam operations. Repair work will begin in early September and is anticipated to be completed within eight weeks.

Throughout the summer, releases will drop reservoir levels by 2 to 5 feet each day (this is called a draw down). Roughly 96% of the water in the lake will be emptied by the draw down. Recreational access at Cherry Reservoir will be impacted during both the draw down and the repair work. High-flow water releases during this time will also impact recreation downstream of the dam.

Visitors will be able to camp and fish without being impacted by the draw down through August. However, as the lake level drops, it will become more challenging to put a boat in the water. After September 5, motorized boats will not be allowed on the lake, although kayaks and non-motorized water craft will be permitted.

While the valvehouse is under repair, a pumping system will be installed to provide releases downstream of the dam to maintain aquatic habitat in Cherry Creek. A residual pool will also be maintained behind the dam to provide enough water for the fish and water for downstream releases. Once the work is complete, the reservoir will be refilled and will return to normal operations. Normal weather patterns should help to naturally restore water levels by summer 2018.

About the SFPUC and Cherry Valley Dam

The San Francisco Public Utilities Commission (SFPUC) owns and operates Cherry Valley Dam as part of the Hetch Hetchy Regional Water System (HHRWS). The HHRWS provides water to 2.7 million customers in the greater San Francisco Bay area as well as the town of Groveland.

The water stored in the reservoir:

is used to generate hydroelectric power at Holm Powerhouse;
serves as an approved standby water source for the HHRWS;
meets SFPUC obligations to senior water right holders; and,
provides recreation on the reservoir and in Cherry Creek and the Tuolumne River.