FLINT, Mich. — A 2015 inspection report warned that the Thread Lake Dam in Flint was in poor condition years before it breached during flooding last month.
The Flint River Watershed Coalition announced last week that the dam’s western side failed due to melting snow and heavy rain.
A field inspection from April 2015 identified maintenance issues at the dam’s embankments, spillways and control structures, the Flint Journal reported . The report recommended the city address the issues, according to records from the Michigan Department of Environmental Quality.
The inspection revealed that one of the dam’s two large gates isn’t operable. The left gate was burdened with the work, but had issues opening and closing. That gate had trouble opening during the February flooding, which forced water to move over the dam instead of through it.
The water eroded a portion of the embankment when going over the dam.
“This is called partial dam failure,” said Byron Lane, supervisor of hydrologic studies and dam safety for the DEQ.
The coalition has monitored water quality and conditions at the lake and at Thread Creek after the breach. The group noted that sediment from Thread Lake could be contaminated due to historic industrial activity in the area. Coalition members have urged the city to investigate possible sediment issues.
The breach has been temporarily filled with sandbags. Water levels at Thread Lake remain low while the city figures out possible repairs.
“That is just a temporary solution, it’s not reliable,” Lane said. “They need to work on a permanent solution before another flood occurs.”
Flint is working with an engineering firm and the DEQ to determine a solution to repair the dam, said Kristin Moore, city spokeswoman.
A timeline for the repairs remains unclear.
Information from: The Flint Journal, http://www.mlive.com/flint