FERC Part 12D Dam Safety Inspections
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A California utility company owns and operates numerous dams as part of several hydroelectric systems located throughout California.

In accordance with the requirements of the Federal Energy Regulatory Commission (FERC) and of Part 12D of Title 18 of the Code of Federal Regulations, the utility company must retain an Independent Consultant (IC) to conduct safety inspections for each dam every five years. The safety inspections also include potential failure mode analysis (PFMA) workshops.

Geosyntec's Scope of Services

Since 2018, Geosyntec has performed Part 12D safety inspections and conducted PFMA workshops for 11 dams owned and operated by the utility company. The inspected dams included large concrete-faced rockfill dams, embankment dams, concrete gravity dams, and masonry dams. Appurtenant structures and facilities associated with the dams included spillways (gated and ungated), penstocks, powerhouses, intake structures, low-level outlets, and dam surveillance and monitoring equipment and instrumentation. For each of the Part 12D safety inspections, Geosyntec managed a team that included the IC, PFMA facilitator, and PFMA recorder, with support from various subject matter experts. The team performed a review of existing safety reports and records such as site investigation records, surveillance and monitoring plans and records, geologic reports and records, hydrologic and hydraulic reports and assessments, structural assessments, seismic and slope stability analyses, seismic hazard assessments, and others. The team also performed field inspections of each dam and its appurtenant structures and facilities. Following the field inspections, Geosyntec led PFMA workshops that included reviewing and updating existing PFMs, development of new relevant PFMs, and preparation of a PFMA report addendum.

Based on the results of the field inspection and the PFMA workshop, Geosyntec prepared a Part 12D Safety Inspection Report for each dam in accordance with FERC requirements. Each report contained clear and concise recommendations for the utility company aimed at enhancing the overall safety of each project. Geosyntec and the IC also provided follow-on services to the utility company related to reviewing analyses, studies, and reports generated to address the recommendations contained in the Part 12D reports.

Geosyntec also supported the utility by updating the Supporting Technical Information Document (STID) for each dam.

Notable Accomplishments

Geosyntec leveraged existing data and information to efficiently facilitate several virtual PFMA workshops in 2020 and 2021 due to the COVID-19 pandemic. All P12D reports were submitted to FERC on time and to date none of the 11 P12D reports have required modification following FERC review.