Anderson Dam Outlet Tunnel
Client:
Santa Clara Valley Water District (Valley Water)
Location:
Morgan Hill, CA
As part of the Anderson Dam Seismic Retrofit Project a new tunnel is being constructed to allow Valley Water to reliably and quickly drawdown the reservoir and provide a greater ability to maintain water levels.
The new outlet system will consist of a 1,700-foot-long underground tunnel up to 25 feet in diameter, 8-foot-diameter lake tap, outlet structure, and discharge channel. It also includes the reopening of the original Coyote Creek channel (northern channel) downstream of the existing dam, improvements to the reservoir rim, and stabilization of the bank and existing intake structures. Additional project components include concrete weirs, road work, utility relocation, revegetation, traffic controls/detours, and community outreach coordination.
After the tunnel and a full reservoir drawdown is complete, the outlet system will be converted into a larger diversion system to bypass flows during the removal and reconstruction of the existing dam. Valley Water plans to begin construction on the new dam in 2025 and anticipates returning the reservoir to its original storage capacity by 2030.
