Shown: Virginia Ranch Dam spillway during recent inspection
Kleinschmidt’s Focused High-Priority Spillway Inspections
Following the February 2017 spillway failures at Oroville Dam in California, the Federal Energy Regulatory Commission (FERC) directed focused spillway inspections and assessments for all U.S. dams with high- and significant-hazard potential and similar spillways. FERC advised these inspections to occur by year-end to reduce risk of similar incidents.
When FERC requested Browns Valley Irrigation District (BVID) to quickly review documents and inspect their Virginia Ranch Dam, BVID turned to Kleinschmidt Associates in Portland, Oregon, for support. Constructed four years before the Oroville Dam and 17 miles away, the Virginia Ranch Dam has several chute spillway characteristics like Oroville’s service spillway that merited additional investigation. FERC gave BVID 30 days to submit a detailed inspection plan for review and then complete a focused Potential Failure Modes Analysis (PFMA) assessment during their annual dam safety inspection before the end of 2017.
Kleinschmidt senior civil engineer Jeff Coffin, P.E., is performing a comprehensive document review, and he has developed a detailed field inspection plan and led the joint field inspection team that consisted of members from FERC, BVID, and other consultants in June. The non-destructive site inspection included a visual inspection of the 920-foot long spillway and assisted in determining the appropriate sounding technique to identify potential voids underneath the concrete spillway slab. While at the site, Jeff also facilitated a focused PFMA assessment with the inspection team to identify potential failure modes that may not have been fully considered in the past but have been recently highlighted due to the Oroville Dam incident. Kleinschmidt is preparing a final report that summarizes the inspection and PFMA session and identifies follow-up steps and potential risk reduction measures for BVID.
Due to Kleinschmidt’s responsiveness in addressing emerging needs in dam safety, FERC accepted BVID’s detailed spillway assessment plan and focused PFMA requirements. The result of the spillway assessment will provide BVID with a better understanding of the current spillway condition as well as potential failure modes that may have not been previously identified.
For more information, contact senior manager Russ Sanford (Russ.Sanford@KleinschmidtGroup.com; 803-462-5621). Kleinschmidt Associates works primarily with energy companies in North America to protect and enhance the environment without compromising performance. We work at the intersection of regulatory requirements, environmental science, and engineering solutions. For half a century, Kleinschmidt has been bringing new ideas to the table, offering practical solutions to tough problems and sensitive issues. Our goal is to bring energy, water, and the environment into balance.