Project Specifics

Geosyntec serves a power utility company that provides electricity to a large population covering a territory of tens of thousands of square miles. The company has a large inventory of hydroelectric plants and dams. The utility is continually striving to implement dam safety best practices and is under regulation by the Federal Energy Regulatory Commission (FERC).

Geosyntec Scope of Services

Geosyntec is providing support services as part of an on call dam safety contract. Some of the tasks completed include:

• Geotechnical engineering and Risk Informed Decision Making (RIDM) subject matter expert during the Semi Quantitative Risk Assessment (SQRA) and Quantitative Risk Assessment (QRA) and related Potential Failure Mode Analysis (PFMA) of a concrete faced rock fill dam subject to potential overtopping under the newly promulgated FERC Risk-Informed Decision-Making Guidelines.
• Geotechnical, seismic, and structural stability evaluations for a series of three concrete gravity dams and related earthen embankments retaining a reservoir with a height of over 200 feet.
• Seismic structural evaluation of a steel drum gate on a concrete multiple-arch dam. Developed a 3D finite element model of the drum gates and conducted evaluations considering hydrostatic, hydrodynamic, and seismic loading.
• Geotechnical stability evaluations for an embankment dam retaining a water supply reservoir with a height of over 200 feet, originally constructed using hydraulic fill. Evaluations included an assessment of liquefaction potential and resulting static and seismic stability using residual strengths.
• Condition/functionality evaluations of 29 standpipe-type piezometer installations with vibrating wire transducers, associated electrical components, and an automated datalogging system for a large embankment dam site.
• Field Investigation Work Plans to address potential dam safety concerns at a variety of facilities, including embankment dams (both compacted and placed using sluicing) with heights up to 165 ft.
• Implementation of significant updates to the Supporting Technical Information documents (STIs) for numerous dams in support of the FERC Part 12D process and annual reviews.

Notable Accomplishments

Geosyntec has successfully integrated with the utilitiy’s staff to complete tasks previously completed by the client such as preparation of FERC-required STI reports, stability assessments, and investigation work plans. Geosyntec also supported the client in the first QRA conducted under FERC’s interim RIDM guidance.

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