A proposal to remove the Hamilton Dam prompts Flint River dredging project
A century-old legacy of Flint’s industrial past is the focus of a major cleanup project this summer.
The Flint River is the main artery flowing through Flint’s industrial heart. For decades, from the late 1800’s and into the 1920’s, a gasification plant located along the river turned coal into much-needed natural gas.
Over time, the coal tar waste produced by the plant ended up in the Flint River, just upstream from the Hamilton Dam. The dam helped contain the coal tar, which sunk deep into the river bed.
Watch the video below to see exclusive footage of the dredging site:
Consumers Energy bought the plant in the 1920s and eventually closed it in the 1950s.
The plant itself is long gone. But the coal tar remains. Though, according to project manager Andrew Santini, not for much longer.
“Right now, we’re near the upstream extent of our dredge cut," he says. "The excavator is removing sediment from the river bottom and placing it into a scow.”
The scow brings the muck to the river bank where it’s off-loaded and transferred to a large fabric-covered area. There the water is drained off, purified and discharged into Flint’s sanitary sewer system. The dried contaminated sediment will later be trucked to a nearby landfill.
Consumers spokesman Kevin Keane says discussions about removing the crumbling Hamilton Dam just downstream spurred the utility to act now to clean up the site, for which it's responsible.
“With the upcoming changes, proposed changes, to the Hamilton Street Dam, it’s important for us to correct the river bottom and improve the hydraulics of the river prior to the dam changes,” says Keane.
Before it’s all done, crews will excavate about a five-foot-deep trench from one end of the dredge site to the other, removing more than 80,000 cubic yards of coal tar-contaminated muck from the river bed.
As you might expect, the dredging project is under the watchful eye of state environmental officials, as well as those who have a special love for the Flint River.
Rebecca Fedewa is the executive director of the Flint River Watershed Coalition.
The coalition supports the dredging project, though Fedewa says they are concerned it could release contaminants that might get downstream.
“We definitely want to make sure that that’s minimized or negated completely,” says Fedewa. “So we’re going to be doing a little testing downstream to just make sure we’re not picking anything up.”
Before the dredging began, two screens were draped across the Flint River, separating the dredge site from the river flowing downstream. The screens are intended to trap particles freed up by the dredging and capture any oil sheen drifting down the river.
Jim Innes is an environmental quality analyst with the Michigan Department of Environmental Quality. He expects the curtains draped across the river will catch most of the contaminated materials.
“It’s not a direct health threat, and the concentrations that would escape from this process would not be anything that would endanger fish or any higher forms of wildlife," he says.
Innes says the contamination could affect some organisms at the bottom of the food chain, and that’s reason enough to keep it contained.
The dredging work is expected to take most of the summer. After that, crews will begin rebuilding the riverbed with sand, clay and rock. They will also take steps to make the riverbank look more natural.