TRAVERSE CITY — Tom Gardner keeps a watchful eye on the Boardman River and wants to know who to blame after a dam breach flooded his property and changed the river’s character.
The Brown Bridge Dam breach during a planned draw down in October 2012 damaged 66 downstream properties and filled the river with sediment. Since the breach, Gardner and other residents in the Boardman Plains neighborhood struggled through recurring floods.
“I’d certainly like to know how this was created and what mistake happened,” Gardner said.
Engineers with the Michigan Department of Environmental Quality Water Resources division on Monday released to the public a long-awaited analysis of the cause of the dam breach. But the report stops short of casting blame.
“We undertook this analysis to determine the cause,” said Bill Creal, chief of the Water Resources Division. “We did not point fingers.”
Engineers determined the control structure, a type of causeway through the earthen dam designed to lower the water impoundment behind it, was too short for the sandy soils upon which it sat. High water pressure created by the 170-acre pond pushed the sand out from underneath the short concrete slab that comprised the bottom of the control structure.
The flow increased quickly through the new channels, eroding the soils from underneath the foundation of the control structure, the report found. The water scoured out the adjoining earthen embankment from underneath until it collapsed and the dam completely failed, releasing the waters behind it.
The Brown Bridge Dam was the first of three dams slated for removal along the Boardman River. Creal said part of the impetus behind the DEQ’s analysis was to make sure a breach won’t happen again. He said the DEQ will require longer control structures on sandy soils in the future.
Completion of the report also allowed DEQ officials to begin negotiations with the city to resolve the outstanding violation of their dam removal permit, Creal said.
The breach resulted in multiple lawsuits from property owners such as Gardner against Traverse City, the Boardman River Dams Settlement Agreement Implementation Team and engineering and construction firms involved in the dam’s removal.
The plaintiffs contend the dam’s removal caused the flood that damaged their property and diminished the river’s natural qualities. They seek millions of dollars in damages.
Kristyn Houle represents three groups of property owners who filed lawsuits. She declined comment about how the report may affect the lawsuits.
“I can’t comment on that until our expert looks it over,” she said.
Attorney Scott Howard, who represents the dam removal implementation team, a committee of state and local government officials, said the report’s conclusions are clear.
“The soils underneath it washed away and it wasn’t built in a way to protect against that,” Howard said.
Howard said responsibility lies with the engineering firm AMEC, the lead contractor on the removal project.
“We hired professionals to serve in their professional capacity,” Howard said. “This wasn’t a negligent hire; we hired experts in their field.”
Amec representative Sandra Sroonian said she’d have to consult with an office manager before she could comment on a case under litigation.
Traverse City attorney Craig Elhart also represents plaintiffs in Brown Bridge dam-related litigation. He hadn’t read the DEQ report but he expects it will impact the case.
“It will be evidence and be used as evidence,” he said.
A 12-day civil trial is scheduled to begin Nov. 4 in 13th Circuit Court.