About 10,000 central Michigan residents have been forced to evacuate their homes after a small hydroelectric dam beset by safety violations failed under heavy rainfall this week.
An earthen embankment at the 4.8-MW Edenville Dam in Midland County collapsed Tuesday, followed hours later by an overrun of the nearby Sanford Dam, flooding the surrounding area in up to 9 feet of water and prompting an emergency declaration by Gov. Gretchen Whitmer.
“If you have not evacuated the area, do so now and get somewhere safe,” Whitmer said Tuesday. “This is unlike anything we’ve seen in Midland County.”
Michigan had previously rated Edenville in unsatisfactory condition, while Sandford received a fair rating. Both dams are about 95 years old and in the process of being sold.
FERC in 2018 revoked owner Boyce Hydro’s hydropower license to operate Edenville, located between Wixom Lake and the Tittabawassee River, citing concerns about the dam not being able to handle floods.
Violations included failing to increase spillway capacity to address the increased likelihood of more frequent flooding; performing unauthorized dam repairs and excavation; neglecting to file a public safety plan or follow its own water monitoring plan; failing to acquire all property rights; and failing to construct required recreation facilities near the dam. The commission has spent about 15 years trying to get Boyce, which has owned the dam since 2004, to increase spillway capacity, the most serious of the safety violations.
Boyce has twice sought rehearing on FERC’s decision to no avail. (See Closed Michigan Dam Loses Rehearing Bid.)
The Office of Energy Projects’ Division of Dam Safety and Inspections “has determined that the failure of the project dam could result in the loss of human life and the destruction of property and infrastructure,” FERC warned in 2018.
FERC also said Boyce’s unexecuted plan to repair the spillways and use the temporary installation of a cofferdam for four to six months would “reduce the spillway capacity by approximately 50%, increasing the potential for overtopping of the dam.”
