Dismantling of 50-year-old dam aims to open water for fishing, boating

A Linn County and Iowa Department of Natural Resources project has shaved nearly three feet off the top of Buffalo Creek Dam near Coggon.

As silt - which has backed up behind the dam over its roughly 50 years in operation - filters downstream, plans are in place to take as much as another seven feet off the Linn County dam over the next three to five years.

When the nearly $700,000 project is finished, the low-head dam is to be replaced by rock arch rapids, which aim to enhance public safety and open the waterway to kayakers and fish alike.

Ryan Schlader, community outreach with Linn County Conservation, said the first stage of the project, which took place over the course of two weeks in March, is one of several steps to eliminate the dam.

'It's a project that takes place over time,” he said. 'We're just waiting for the next high-water event, meaning some heavy rains or flooding in that area. Once the water passes, that will loosen up the silt and we're able to get the contractor back out there and do it once again.”

The Buffalo Creek Dam, which cannot regulate or control water flow, was built in 1965 to create a body of water to provide a place for recreational boating and fishing at the nearby Buffalo Creek County Park. However, 50 years of impounded silt behind the dam created an area inhospitable for most aquatic wildlife and an unappealing spot for recreation, Schlader said.

In 2014, Linn County Conservation began soliciting feedback from the public to find the appropriate course of action for the dam. Last fall, Reinbeck's Peterson Contractor Inc. was awarded the roughly $690,000 contract to mitigate the dam.

The entire project, including design, engineering, wetland mitigation and about $100,000 in contingency funds, could come in at around $970,000, according to Schlader. Project funding has come from the Iowa DNR's Dam Mitigation Program and Fish Habitat Program, U.S. Fish and Wildlife Service and local sources.

Nate Hoogeveen, director of river programs with the Iowa Department of Natural Resources, said dam mitigation projects can be costly, but the DNR works with communities to find the best option available.

'I think a unique thing we're doing from an Iowa Department of Natural Resources standpoint is, helping each of these communities and our partners get these projects the right size,” Hoogeveen said.

Iowa DNR has placed priority on eliminating the state's more than 150 low-head dams, which have been deemed unsafe, as their design creates a dangerous recirculating current of water, Hoogeveen said.

Hoogeveen said Iowa's low-head dams - often called roller dams - average one and a half fatalities a year.

'First and foremost it's safety, these structures are inherently dangerous,” he said.

In about the last three years, Iowa has reduced its stock of low-head dams by about 15 structures, but 162 still remain.

On top of safety, transforming the Buffalo Creek Dam into a stretch of rapids also is to filter the impounded silt out of the recreation area, revitalize mussel habitats downstream and open the waterway to aquatic life and boaters.

'We'll be able to tell a story about a recovery on this stream,” Hoogeveen said. 'How often to we get to say that in Iowa?”