The Importance of Grouting and Its Impact on the FERC Dam Safety Program-Paper

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The Federal Energy Regulatory Commission (FERC) oversees the safety of approximately 2,500 non-federal hydropower dams and related structures. Through its Division of Dam Safety and Inspections, FERC reviews designs, construction plans, monitoring programs, emergency plans, and inspection findings to help protect life, property, and the environment. Dam owners remain responsible for project safety, while FERC provides regulatory oversight under federal regulations and engineering guidelines.<br /><br />Potential failure modes vary by project and may involve seepage, internal erosion, piping, unstable foundations, concrete-joint movement, spillway erosion, or problems in tunnels and conduits. Risk assessments and Potential Failure Mode Analyses help identify vulnerabilities and determine priorities for investigation and corrective work.<br /><br />Grouting is an important tool for addressing these risks in both new construction and remediation. Applications include seepage-control curtains, foundation and consolidation grouting, cavity filling, soil stabilization, tunnel and conduit repairs, and treatment of karst foundations. Methods may include rock-fissure grouting, high- or low-mobility grout, jet grouting, soil mixing, and contact or compensation grouting. The appropriate method depends on site conditions and the failure mechanism being addressed.<br /><br />Grouting itself can threaten dam safety if poorly planned or controlled. Drilling may damage a dam’s core, drains, instrumentation, or embedded features; excessive pressure can hydrofracture soil or rock, create seepage paths, or destabilize foundation blocks. These risks are especially significant in embankment dams. FERC therefore requires careful planning, qualified on-site oversight, and evaluation of foreseeable risks before work proceeds.<br /><br />Case studies illustrate the range of applications, including grout-curtain installation during the Gross Dam expansion, ongoing treatment of the karst foundation at Logan Martin Dam, and grouting and soil-stabilization work to support an intake structure excavation. Overall, effective grouting—combined with sound risk assessment, engineering review, and regulatory oversight—is central to maintaining dam integrity and reducing public risk.
Keywords
FERC
dam safety
hydropower dams
grouting
seepage control
foundation grouting
risk assessment
potential failure modes
embankment dams
regulatory oversight