Maquoketa River eroding Lake Delhi sediment - KWWL - Eastern Iowa Breaking News, Weather, Closings

Maquoketa River eroding Lake Delhi sediment

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DELAWARE COUNTY (KWWL) -- The Maquoketa River is cutting through 80 years of collected lake bed sediment, causing problems downstream.

Keith Krause is a conservationist with the Natural Resources Conservation Service in Delaware County. He said the Lake Delhi dam acted as a sediment trap.

"With the dam being gone, that stream is trying to get back to its original gradient, and it's taking the sediment out with it," Krause said. "This sediment is being allowed to freely move, and it's filling in the Maquoketa River, filling in fishing holes, impacting aquatic life in the stream."

Krause said erosion is deepening the channel at a rate of four to six feet per day. While the channel isn't widening at this point, Krause said future flooding could do that if left unfixed.

The lake bed silt is comprised largely of sediment that has washed off farmland. Krause said once it's off the land, it's difficult to deal with.

"It's kind of like a weed," Krause said, of silt. "It's out of place, so it would be worthless in the lake or the river, but on the fields it would be very beneficial."

Lou Christiansen lives on what was Lake Delhi and said he and his wife have watched over the past few weeks as the Maquoketa River channel has cut deeper and farther upstream.

"It's just amazing how far it's moved today," Christiansen said, looking out at the channel.

The couple lives about a mile upriver from the broken dam.

Experts have been talking about the possibility of the channel eventually hitting a barrier of rock rapids upriver, which could stop the erosion. No one can know what will happen, however, until the channel actually reaches that point.

Conservationists and officials, including the governor's Lake Delhi Task Force, are searching for a solution.

One option is to rebuild the dam, although FEMA last week denied federal dollars for that project.

"The main thing would be if the lake would never get rebuilt, to try to stabilize it with some cofferdams or rock chutes or some things like that," Krause said.

One short-term option officials have been discussing is seeding the lake bed with a cover crop to help stabilize it.

"I think it's going to take more time for the powers that be to get together and see what solutions are economically feasible and fit the problem at hand," Krause said.

The governor's task force has until Dec. 1 to come up with a proposed long-term solution for Lake Delhi.

Online Reporter Becca Habegger

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