Analysis of Dam Failure and Incident Investigations in the United States from 1960 through 2022: Framework for Improving Future Investigations

Abstract

There are multiple dam failures and dam safety incidents every year in the United States. There are currently no standard policy requirements for when or how to conduct failure or incident investigations. In order to understand the state of the industry, this study reviewed 58 different dam failure or incident investigation reports based on incidents that occurred in the United States from 1960 through 2022. The investigations ranged from well-known failures/incidents of large dams such as Oroville Dam and Teton Dam, to little known structures such as Hawkins Dam, a small dam in the state of Washington that had a spillway failure in 2014. The investigations were analyzed and evaluated for characteristics such as the length of time for the investigation team to get on-site, the amount of time to complete the full investigation, what organization funded the investigation, independence of the investigation team, scope of the investigation, and several other parameters. Based on the analysis, investigations after the year 2000 have seen more time pass before the investigation team can visit the site and investigations have taken longer to complete. Investigations are often not fully independent, are most commonly funded by federal agencies, and often do not investigate human, programmatic factors, or consequences. This paper makes 10 recommendations for improving investigations in the future, including recommended definitions for incidents and failures. In this paper, the authors recommend that (1) a dam safety incident be defined as a potential failure mode has initiated and progressed but has not led to an uncontrolled release from the reservoir; (2) a high flow release be defined as: An incident when there are consequences downstream of a dam due to controlled flows passed by the dam, not due to the failure of a dam or dam component; and (3) that dam failures be separated into three types based on the severity of downstream consequences.