CS16C - Concurrent Session 16C: Idaho Dam Safety Portfolio Risk Assessment - 7 High Hazard Dams

In September 2021, Idaho Department of Water Resources (IDWR) issued a Request for Qualifications to develop a Failure Mode/Effects Analysis for seven high hazard dams located throughout Idaho. The IDWR Dam Safety Program had previously identified this group of non-federal dams due to perceived existing structural, mechanical or operational deficiencies; or because the design or construction methods do not meet currently established safety standards for high hazard potential dams (HHPD) with respect to potential downstream failure consequence(s).

McMillen Inc. (formerly McMillen Jacobs) reviewed available documentation, conducted site inspections, and performed a semi-quantitative risk analysis (SQRA) to accomplish the stated objectives listed in the IDWR Scope of Work. The SQRA captures key information and provides the rationale that supports a summary report with recommendation(s) for reducing or otherwise mitigating risks. Other outcomes include a better understanding of the project and the primary risk-drivers, better prioritization of studies, and more focused inspections and surveillance and monitoring. The SQRA focused on credible potential failure modes (PFMs) to determine which scenarios are considered the most significant at each dam.