A modern upgrade for Coyote Percolation Pond

July 30, 2026

A view of the new inflatable dam at the Coyote Percolation Pond.

Valley Water recently reached an important milestone at Coyote Percolation Pond in San José by successfully testing its new inflatable dam. The dam inflated in about 30 minutes after crews completed the system's power connection earlier this summer. The dam is expected to be fully operational this fall.

The newly installed inflatable dam replaces an aging steel flashboard dam that took crews several days to remove. Unlike the previous system, the inflatable dam gives Valley Water greater flexibility to respond to changing creek conditions while continuing to support groundwater recharge. During dry weather, the dam can be raised to hold water in the Coyote Percolation Pond. This allows it to soak into the ground and replenish local groundwater supplies. During storms or periods of higher creek flows, the dam can be lowered to safely release water downstream.

This improved flexibility is especially important as Valley Water continues work on the Anderson Dam Seismic Retrofit Project. The new dam allows for larger releases from Anderson Reservoir when needed and helps maintain groundwater recharge at the percolation pond. This protects local groundwater basins, nearby communities, and aquatic habitat by better managing creek flows.

Watch our 35-second time-lapse to see the inflatable dam go from fully deflated to fully inflated over the course of 30 minutes.

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. Valley Water 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 280 acres of groundwater recharge ponds and 350 miles of waterways. 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.