Dam Safety Reviews and Potential Failure Mode Analysis
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The Santa Clara Valley Water District’s (Valley Water) Dam Safety Review Project (DSRP) provided an independent safety review and evaluation of four Valley Water dams: Anderson, Almaden, Calero, and Guadalupe.

Anderson Dam, in particular, is a FERC-regulated project and as such, Valley Water is required to commission an independent Part 12D dam safety review every five years, and the performance of a Potential Failure Mode Analysis (PFMA) workshop with updates as appropriate thereafter.

Geosyntec's Scope of Services

For Anderson Dam, in 2012 Geosyntec updated the existing PFMA report, and the Supporting Technical Information (STI) documents based on review and incorporation of numerous studies and other programs (e.g., dam instrumentation data, seismic stability evaluations, changes in operation and maintenance) that were in process during or begun after, the previous Part 12D inspection in 2007. Geosyntec used these updated documents in tandem with a field inspection of the dam (including participation by Valley Water and FERC staff) to develop the FERC Part 12D Safety Inspection Report. Geosyntec performed the subsequent Part 12D safety inspections and reports in 2016 and 2021, including PFMA workshops focusing on interim conditions until completion of a planned seismic retrofit project.

For Almaden, Calero, and Guadalupe dams, which are not regulated by FERC, Geosyntec conducted document reviews, field visits, and PFMA workshops. Valley Water, California Division of Safety of Dams (DSOD), and Subject Matter Expert (SME) input were incorporated in development of new PFMA reports and STI documents for each dam.

Geosyntec is also leading the team conducting the Owner’s Dam Safety Program (ODSP) external audit for Valley Water. The Dam Safety Program (DSP) external audit is a FERC requirement, separate from the Part 12D safety review, to be conducted by an independent reviewer at least every five years for owners of one or more high hazard dam.

Notable Accomplishments

The Part 12D safety reviews for Anderson Dam are helping Valley Water plan a dam retrofit project estimated to cost $648 million to address seismic stability concerns. The PFMA workshops and STI compilation documents prepared for Almaden, Calero, and Guadalupe dams have helped Valley Water to formalize and prioritize the dam safety program for these dams, as well as to document key aspects of dam history and performance that will serve for future planning efforts and safety reviews. The ODSP external audit will help Valley Water to discern how well their DSP is working and help identify areas of improvement. Geosyntec continues to provide FERC Part 12D services for Anderson Dam.