Edenville Dam
Edenville Dam was an earthen embankment dam at the confluence of the Tittabawassee River and the Tobacco River in Mid Michigan, United States, forming Wixom Lake. The dam was about north of Edenville, mostly in the southeast corner of Tobacco Township in Gladwin County, with its southeastern end reaching into Edenville Township in Midland County. Its height was, the length was at its crest.
The dam was built in 1924 for hydroelectric power and flood control. The dam was equipped with two 2.4 MW turbines capable of generating 4.8 MW of electricity in total.
In May 2020, following heavy rains, the Edenville Dam breached and the Sanford Dam downstream overflowed, which caused major flooding in Midland County, including the city of Midland.
History
The dam was built in 1924 by Frank Isaac Wixom, after whom the reservoir formed by the dam is named. Wixom used to own a circus before he built the dam.The dam is privately owned and operated by Boyce Hydro Power, a company based in Edenville, which also owned three other hydroelectric facilities on the Tittabawassee: the Secord, Smallwood, and Sanford Dams.
Safety and lake level disputes
In an exercise of a rarely used legal authority, the Federal Energy Regulatory Commission terminated Boyce Hydro Power's license in 2018, because of its "inability to pass the Probable Maximum Flood ", as well as seven other failures. The Commission was concerned that "the dam may not have the ability to pass enough water, if a severe flood were to hit, among other issues and violations."Following the Commission's 2018 license revocation, the Michigan Department of Environment, Great Lakes, and Energy took oversight of the dam. EGLE determined that the dam was structurally sound. Edenville and the other former Boyce dams were taken over in 2019 by the Four Lakes Task Force, a county delegated authority, with title to transfer in early 2022. The State of Michigan appropriated $5 million for the purchase. The Four Lakes Task Force operates under the Four Lakes Assessment District in the State of Michigan, created in May 2019 by Judge Stephen Carras. In 2019, Michigan's 42nd Circuit Court was involved in determining if only the lakefront owners or all area residents would pay tax to the Four Lakes Assessment District.
In October 2018, and again in mid-November 2019, the dam's operator lowered the water level, in what it called a safety move. It said it had requested a permit to lower the level from Michigan's EGLE, a permit that was not issued. The operator said it acted “due to concern for the safety of its operators and the downstream community,” and went on to sue EGLE in federal court, alleging "its safety concerns were paramount."
In December 2019, the Federal Energy Regulatory Commission issued a permit to investigate expanding the hydropower plant with a second powerhouse containing one 1.2 MW turbine-generator unit for a total of 6 MW.
The dam's operator said it began to raise the lake's water level in April 2020, under threat of being sued by Michigan's EGLE, and that it reached "normal pond level" in the first week of May 2020. Michigan's Attorney General Dana Nessel confirmed EGLE had directed the operator to raise the water level, stating: "Michigan EGLE directed Boyce to follow the court-ordered lake level requirements," but challenged that the operator had lowered it for safety reasons.
In April 2020, EGLE sued Boyce, alleging it had lowered the water level without permission in 2018 and 2019, killing thousands of freshwater mussels.
In October 2022, however, a federal judge accepted as basic facts that Boyce had conducted what the Michigan Attorney General called a "propaganda" campaign trying to blame the State of Michigan for keeping water levels high, when in fact, Boyce had continually touted the structural safety of the Edenville Dam.
Dam failure
On 19 May 2020 at 17:46 EDT heavy rainfall pushed inflows far beyond design capacity and the east embankment of Edenville Dam gave way. Immediate, mandatory evacuations were ordered for residents of Edenville and nearby Sanford. Roughly downstream the impounded water overtopped – but did not breach – the Sanford Dam, forcing the evacuation of much of Midland another downstream.Governor Gretchen Whitmer declared a state of emergency that evening and directed state regulators to open an investigation into Boyce Hydro, the dam’s private owner. More than 10 000 people eventually fled their homes; officials also urged evacuees to observe social‑distancing rules because the failure occurred during the COVID‑19 pandemic.
The Tittabawassee River crested at during the night of 20 May, inundating eastern Midland and severely damaging the village of Sanford. Satellite imagery released two days later showed a new river channel carved around the failed spillway. Although floodwater surrounded parts of the Dow Chemical complex in Midland, the company reported no serious damage to critical infrastructure. No fatalities or serious injuries were recorded.