Dismantling of low-head dam near Coggon nearly complete

COGGON - The 50-year-old Buffalo Creek Dam near Coggon in northern Linn County is no more and, in its place, rock arch rapids are taking shape.

Contractors working with Linn County Conservation earlier this year completed the three-phase project that included shaving 7 feet off the once 10-foot-tall, low-head dam, which faced safety and environmental concerns.

In the final weeks of December, crews have been laying rock in the Wapsipinicon River to create rapids.

Dennis Goemaat, deputy director of Linn County Conservation, said the 'stair-stepped” rock rapids provide many benefits over the old dam.

'It allows the water to more calmly go down the creek,” he said. 'The two primary reasons for undertaking the project were environmental and safety.”

Ryan Schlader, spokesman for Linn County Conservation, said the project is expected to be finished by the end of the year.

The project's construction costs are around $700,000, with engineering adding another $140,000.

With five-year monitoring after the project's completion, to make sure wetlands aren't negatively impacted, the entire effort will likely cost less than $1 million total, Goemaat said.

Buffalo Creek Dam was one of about 190 low-head dams remaining in Iowa, according to the Iowa Department of Natural Resources. Linn County had five of those dams in 2010, according to a river dam inventory done that year.

Low-head dams were originally built for a variety of purposes, including running mills, generating electricity or for recreational purposes by creating reservoirs.

The dams have come under fire in recent years for their negative effects on the environment, water quality and wildlife.

Also called rolling dams, for the recirculating current created when water flows over the dam, the structures also create safety concerns.

The Iowa Whitewater Coalition reports that more than 160 people have died in dam-related incidents in Iowa since 1900.

One of those accidents happened in 2014, when Andrea Zimmermann, 29, of Cedar Rapids, drowned after she went over Linn County's Troy Mills Dam on the Wapsipinicon while tubing with friends.

That low-head dam also is slated to eventually be replaced with rock arch rapids.

Also, the 50-year-old Pinicon Ridge Park Dam in Central City has reached the end of its life span.

A public meeting was held earlier this year to begin discussing what to do with the low-head dam, which also sits on the Wapsipinicon, with some suggesting the development of a white water park such as the one Manchester recently developed on the Maquoketa River in Delaware County.

'It's probably many years out before we get real serious about it,” Goematt said. 'But we want to have an ongoing discussion about it.”

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