Numerous violations and longstanding concerns that the Edenville Dam could not withstand a significant flood led the Federal Energy Regulatory Commission to revoke its license for power generation in September 2018.
The Edenville dam, located on the border of Midland and Gladwin counties, failed late Tuesday afternoon, leading to the failure of a downstream dam on the Tittabawassee River and forcing evacuations in Midland County.
The extent of the damage is not yet determined.
The energy commission (FERC), which regulates U.S. power generation, notified the dam’s previous owner as far back as 1999 that it needed to increase capacity of the Edenville dam’s spillways to prevent a significant flood from overcoming the structure.
FERC subsequently notified the dam’s new owner, Boyce Hydro Power LLC, when the license transferred in 2004.
By June 2017, the commission cracked down, citing the owner’s “longstanding failure to address the project’s inadequate spillway capacity at this high hazard dam.”
“Thirteen years after acquiring the license for the project, the licensee has still not
increased spillway capacity, leaving the project in danger,” wrote Jennifer Hill, director
division of Hydropower Administration and Compliance. “The spillway capacity deficiencies must be remedied in order to protect life, limb and property.”
Notable by FERC was Edenville’s classification as a high hazard dam, meaning its failure could present significant risk to life and property, especially in the downstream village of Sanford, city of Midland and Northwood University.
Boyce Hydro had argued to FERC that it had ongoing litigation with the Michigan Department of Environmental Quality over gaining permits to construct more spillway capacity.
A spillway is essentially an overflow valve, allowing excess water to safely flow around the dam without damaging the structure.
Boyce Hydro owns four dams on the Tittabawassee River, which runs southeasterly through mid-Michigan, emptying into the Saginaw River at Saginaw. The three other dams were still creating hydropower at the time of Tuesday’s breach. They create Wixom, Sanford, Secord and Smallwood lakes.
The Sanford Lake dam subsequently failed on Tuesday.
In January 2019, FERC sent a two-page letter to Boyce Hydro, noting that it had canceled its scheduled October 2018 “functional exercise” at the Sanford, Second and Smallwood dams. Functional exercises simulate an emergency to test preparedness.
The FERC letter reminded Boyce of its duty to conduct the exercise, setting a Feb. 28, 2019, deadline.
FERC did not immediately respond to a request for information on whether that exercise was ever rescheduled.
In January, a two-county authority called the Four Lakes Task Force agreed to purchase the four dams and lakes for $9.4 million from Boyce Trusts, using money from a special tax district to help rehabilitate the structures. The cost of improving the dams was expected to be $100 million and the sale was expected to be complete by early 2022.
That action came after years of citations issued by FERC against the owners of the Edenville dam. They included violations for making unauthorized repairs, unauthorized earth moving, failure to file proper safety plans, failure to provide recreational areas and public access, failure to secure necessary property rights and failure to comply with water quality orders.
But the government’s most significant concern, by far, was the failure to increase the capacity of spillways that would allow the dam to survive a “probable maximum flood” event.
FERC argued that the Edenville structure, constructed in 1925, could not handle 50% of a probable maximum flood for the region and that even Boyce’s insufficient and incomplete plans would increase capacity only to 66% of a probable maximum flood.
In an effort to retain its license, Boyce Hydro and the Sanford Lake Association argued that revocation of the license would not improve public safety, because revoking the license would make the dam less attractive to potential buyers and because ceasing power generation would kill the only other source of revenue that could be used to expand its spillway capacity.
In its 2018 request, Boyce Hydro LLC also argued that the “odds of a ‘probable maximum flood’ event occurring in the next 5 to 10 years is 5 to 10 in one million,” according to federal records.
FERC denied the request for a rehearing, finding that revocation of the license would not endanger the public.
“Michigan DEQ has extensive dam safety regulations, including enforcement mechanisms such as the ability to commence a civil action for appropriate relief for violations,” commissioners found. “For over 14 years, the commission has gone to great lengths to compel compliance with the license requirements and Boyce Hydro has delayed, disregarded its responsibility, and claimed that it was not financially capable of meeting such requirements. Meanwhile, Boyce Hydro continued to benefit from the revenues generated by the project.”
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