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Presentation details plans for removal of two low-head dams

Presentation details plans for removal of two low-head dams
Presentation details plans for removal of two low-head dams
Dr. Jerry Sweeten discusses the removal of two low-head dams on Indian Creek east of Corydon during a presentation Monday evening at the Corydon Town Hall. Jo Ann Spieth-Saylor

Nearly two dozen people turned out Monday evening to hear a presentation and ask questions pertaining to the planned removal of two low-head dams on Big Indian Creek east of Corydon.
Dr. Jerry Sweeten, a professor at Manchester College, who is with Ecosystems Connections Institute LLC, compared the project to a similar one ‘ about 100 miles of Eel River ‘ he was involved with in northern Indiana.
At one time, he said, there were about 1,100 low-head dams in streams throughout Indiana, with most of them put in as a way to grind grain.
Harrison County historian Dan Bays, who attended the presentation, said the dams set to be removed here were built as a back-up water source.
Most of the dams statewide are now privately owned. Less than 10 of them have been removed, Sweeten said.
It was learned through research that these dams disrupt the natural flow of streams and increase fragmentation of the streams’ habitats.
But, that’s not all.
‘These dams are incredibly dangerous,’ Sweeten said, especially the ones set to be removed, due to their height, about 12 feet, which is four times taller than most known dams throughout the state.
Drownings have occurred at least one of the two dams scheduled for removal near Corydon.
Many of the dams in the state, most of which are three feet tall, were initially built out of wood, but, as they rotted, concrete was used to hold the structures together.
To complete the dam removals in Eel River, Sweeten said it took about two years to obtain all of the necessary permits then only about a day to remove each dam.
One dam was determined to have historical value, so about a three-foot-wide portion was left in place.
Neither of the dams here was found to have historical value, so only the foundations will remain.
The Indian Creek watershed, which encompasses 256 square miles, has about 18 dams. The two dams set to be removed are about 2-1/2 miles apart, with one located east of the YMCA of Harrison County and the other farther upstream. (The low-head dam that can be seen from Corydon’s north bridge will not be removed as it is privately owned.)
Sweeten said a fish survey completed at the two dams last summer by Bellarmine University showed the largest population of fish located just below the dams, with the lowest numbers in the pools of water just above the dams.
Ecosystem Connections Institute is just one of several partners working to remove the two dams. Other partners include The Nature Conservancy, U.S. Fish and Wildlife Service, Indiana Dept. of Natural Resources, Purdue University and the Town of Corydon.
Sweeten said they have permits in hand from the Indiana Dept. of Environmental Management with the ones from the DNR to arrive ‘any day.’
Next, the project will be put out for bids, and then a contract for the work will be awarded.
‘We’re on track to remove the dams in October or late September,’ Sweeten said.
To concerns voiced by some in the audience about potential flooding, Sweeten said the dams’ removal will have no affect on flooding.
‘We’re not changing the volume of water nor the speed of the water,’ he said. ‘This will change nothing downstream.’
Rand Heazlitt, Corydon’s town manager, added that the removal of the dams would likely lessen the chance of flooding.
A woman who traps and hunts near Indian Creek, who said she neither favors nor opposes the project, expressed concern about the impact the project could have on other habitat, such as otters and beavers.
‘The only thing we looked at without scales was mussels,’ Sweeten said.
However, he added, from knowledge shared by others about the Eel River project, there was no negative impact on wildlife in the area.
When asked about the possibility of erosion along the newly-created portion of the Indian Creek Trail just west of downtown Corydon increasing, Cassie Hauswald, a freshwater ecologist at The Nature Conservancy, said they would watch for erosion but they are not expecting any to occur. She suggested several species of trees that could be planted to assist with further erosion.
Sweeten said a post-removal survey would be completed.
‘If there’s questions, we will not abandon you,’ he reassured the attendees.
‘The benefits of removing these dams far outweigh’ keeping them in place, Sweeten added. ‘No more young people should die because they got caught in these.’