Title
Receive an Update on the San Antonio Dam Spillway Replacement Project.
Report
SUMMARY/DISCUSSION:
Following the Oroville Dam Spillway failure in 2017, the California Department of Water Resources, Division of Safety of Dams (DSOD) required the Agency perform a condition assessment of the San Antonio Dam Spillway. Ultimately, DSOD mandated the spillway be replaced. The Agency has until December 2031 to complete that replacement project.
The Agency contracted with McMillen Inc. in October 2024 to provide engineering design services for the San Antonio Dam Spillway Replacement Project. The initial tasks included the
Probable Maximum Flood Study and Alternatives Analysis Report to inform the design. Those reports were approved by DSOD in May 2026. McMillen then prepared the 30% Design Drawings and Documentation Report. These were submitted to DSOD in September 2026 with an anticipated 90-day review period.
The Agency contracted with GEI Consultants in September 2026 to perform environmental consulting services. The project kickoff meeting will be held in early October and the activities will closely align with the design work.
The Spillway Replacement Project is on schedule. Key milestones include:
• Fall 2026: Begin CEQA process
• Winter 2027: Construct and test a physical model of the spillway
• Winter 2027: Complete 60% Design Documentation
• Spring 2027: DSOD Review
• Summer 2027: Draft CEQA documentation for public review
• Summer 2027: Complete 90% Design Documentation
• Fall 2027: DSOD Review
• Fall 2027: Final CEQA documentation
• Fall 2027: 100% Design Documentation
• TBD: Final Permitting
• TBD: Construction
OTHER AGENCY INVOLVEMENT:
California Department of Water Resources
FINANCING:
May of 2024, the Agency secured approximately $16.15 million in funds under SB104 for use toward dam safety projects through a funding agreement with the California Department of Water Resources. An estimated three (3) million dollars has been allocated toward the final design of the San Antonio Spillway Replacement Project. This a reimbursable funding agreement and so Agency funds will be utilized to support the project until the reimbursements are received.
Prepared by: Shaunna Murray, Deputy General Manager, (831) 755-4860
Approved by: Ara Azhderian, General Manager, (831) 755-4860