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District releases water from Anderson Reservoir

February 05, 2019
Anderson Dam and Reservoir

Media contact: 408-681-9265

With the recent and expected inflows of water to both Coyote and Anderson reservoirs, the Santa Clara Valley Water District began making controlled releases from Anderson Reservoir at approximately 1 p.m. today, to reduce the chance of the reservoir reaching its restricted storage limit.

Anderson Reservoir is currently operated to reduce the chance of the reservoir level exceeding its storage limit of 58 percent, set by the California Division of Safety of Dams. This restriction is a safety measure that is in effect because of the dam’s seismic deficiencies. Today, the reservoir’s storage is nearly 35 percent of capacity.

District staff assess the likelihood that the reservoir’s storage will reach the storage limit. With the recent storms, the chance that the reservoir could reach that storage limit has increased. Therefore, staff began releasing water through the dam’s outlet at the bottom of the reservoir into Coyote Creek.

The reservoir’s outlet pipe runs through the bottom of the dam and releases water to Coyote Creek. In contrast, the reservoir’s spillway starts near the top of the dam, and only receives water when the reservoir is at or above 100 percent capacity. That last happened in February 2017.

Release flows from Anderson Reservoir can be observed by monitoring the district’s stream gauge on Coyote Creek at Madrone.

On Feb. 5, both Uvas and Almaden reservoirs were at capacity and water was spilling over their spillways, just as they are designed. Some news outlets have reported on an RV park in Morgan Hill, downstream of Uvas Reservoir. The access road to this park is located within the banks of Uvas Creek, and therefore, it is known and expected that this bridge access must be closed when Uvas Reservoir is spilling. As is our standard practice, the district informed the RV park last Thursday that Uvas Reservoir may spill, rendering their access road inaccessible.

The water district is in communication with partner agencies as we make operational changes that affect their jurisdictions.


Valley Water manages an integrated water resources system that includes the supply of clean, safe water, flood protection and stewardship of streams on behalf of Santa Clara County's 2 million residents. The district effectively manages 10 dams and surface water reservoirs, three water treatment plants, an advanced recycled water purification center, a state-of-the-art water quality laboratory, nearly 400 acres of groundwater recharge ponds and more than 275 miles of streams. We provide wholesale water and groundwater management services to local municipalities and private water retailers who deliver drinking water directly to homes and businesses in Santa Clara County.