Independent Forensic Team FInal Report: Investigation of Failures of Edenville and Sandord Dams

On Tuesday, May 19, 2020, the Edenville and Sanford Dams, located in central Michigan, failed. In August 2020, the Federal Energy Regulatory Commission (FERC) engaged a five-member independent forensic team (IFT) to investigate the failures and the physical and human factors that contributed to them. This report presents the results of the IFT’s work. The Edenville and Sanford Dams were two of four dams in Michigan owned at the time of the failures by Boyce Hydro, and located in series along the Tittabawassee River. The other two Boyce Hydro dams were Secord Dam and Smallwood Dam. All four dams were built in the 1920s. Secord is the most upstream of the four dams, followed further downstream by Smallwood, Edenville, and, finally, Sanford. All four of the dams included earthfill embankments, gated concrete spillways, and powerhouses. Sanford Dam also included a fuse plug auxiliary spillway, and Smallwood Dam included an earth-lined auxiliary spillway. At the time of the failures, Secord, Smallwood, and Sanford Dams were active hydroelectric facilities, and Edenville Dam’s powerhouse was inactive because its FERC license had been revoked in September 2018.