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Water quality improvements lead to mussels’ return, Lime Creek off state impaired waters list

  • 1/17/2019 1:44:00 PM
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BUCHANAN COUNTY — For Lime Creek, it’s a tale of two lists; it’s a story that moves from the state’s impaired waters list to the distinction of landing on the Outstanding Iowa Waters list. The effort was also just recognized as a water quality success story by the U.S. Environmental Protection Agency.

The move took the work of the local Buchanan County community, and all hinged on the return of one valuable stream resident.

A survey of native freshwater mussel species in the creek in 1984 found nine different species. But by 1998 there were no live mussels found. With that, one segment of the stream was considered impaired for biological aquatic life.

Locals formed the Lime Creek Watershed Council and launched a watershed project in 2006, aiming to reduce the amount of silt and sediment washing off the land into the creek, as well as reducing the amount of phosphorus and nitrates reaching the water.

The project focused on helping farmers and landowners use practices on the land to better hold sediment and nutrients on the land and keep them out of the creek. With a number of partners and funding sources, including the Iowa Watershed Improvement Review Board (WIRB) and Iowa State University Extension and Outreach, the project helped locals reduce tillage, adjust crop rotations, change nutrient application and install grassed waterways.

More than half of residents in the Lime Creek watershed – the area of land that drains to the creek – participated in the project. After the project officially ended in 2009, locals kept it alive with voluntary practices and efforts.

"Year after year, we've seen interest growing in cover crops and in other practices that improve soil health and water quality," said farmer and conservation leader Dick Sloan of Rowley, who leads the Lime Creek Watershed Council.

As a result, 959 tons of sediment – that’s about 64 dump truck loads – no longer reach the creek each year. The work also reduced phosphorus levels in the creek by almost 1,500 pounds per year and nitrate-nitrogen levels in the creek dropped 19 percent.

Most importantly, because of the improved habitat, the mussels returned. A Statewide Mussel Survey in 2011, led by the DNR and funded by U.S. EPA Section 319, discovered six species of mussels where there were previously none. That includes three species considered threatened in Iowa.

“It’s especially impressive that the most common mussel we found in Lime Creek, the ellipse, is a threatened mussel,” said DNR biologist Jen Kurth, who led the survey. This led to Lime Creek coming off of the state’s impaired waters list in 2014.

Now, as one of Iowa’s Outstanding Waters, this scenic stretch of stream is well-known to visitors to Buchanan County Conservation’s Lime Creek Park and to smallmouth bass anglers in the area.

To learn more about Lime Creek and its success story, visit the U.S. EPA’s website: