President Joe Biden’s infrastructure plan is undergoing work to bring more members of Congress on board. If passed, it could mean significant help for Iowa, with funding for areas that need more work like the high number of structurally deficient bridges. One other potential benefit could address Iowa’s efforts on local dams.
The state’s dam mitigation project started in 2010 and its goal is to make Iowa’s navigable rivers safer by removing or lessening the effect of existing low-head dams.
Nate Hoogeveen, the rivers programs coordinator at the Department of Natural Resources, explained that the dams can create dangerous currents that can catch and trap people in a recirculating current that’s hard to escape. Low-head dams have led to death for anglers, boaters, tubers, swimmers and would-be rescuers.
Safer recreation, necessary updates
“A lot of dams were created without public safety really in mind, and they can be very hazardous for just the recreational public nearby,” Hoogeveen said. “These rivers of the size that we’re talking about, they’re all navigable. The public have the right to be there, to be on them.”
That’s why the department works closely with communities to handle these dams. When the project started, the DNR did outreach so communities knew to contact them about any projects they want done. Hoogeveen said it keeps them busy.
The DNR mostly deals with rivers that are large enough to create the recirculating current, and works with towns, counties and sometimes even individuals.
“Some of that is financial assistance, some of that is technical assistance,” Hoogeveen said. “Assisting them through permitting and just understanding what the responsibilities are to sensibly decommission a dam.”
He said the department also does this maintenance because most of Iowa’s dams are past their service life.
“There’s a number of dams that would come under the heading of aging infrastructure,” he said. “Many of them would have been designed for a 50-year life cycle and many of them are over 100 years old.”
In 2010, the Delhi Dam in eastern Iowa collapsed and flooded what was mostly nearby farmland, but it showed the possible dangers of old dams. It had been built in the 1920s.
Hoogeveen said Iowa has more than 170 dams on major rivers the DNR been involved with mitigating more than 30 of them at this point. According to its website, the DNR has 12 active mitigation projects with more marked for potential projects.
He said they often build rapids instead, because it breaks up the current and takes stress off the dam. It might also be safer or more cost-effective.
“In fact the rapids replace the function,” he said. “Sometimes we might take out a dam to build a rapids in its place to restore the pool and it’s just a different way of looking at the infrastructure in a more natural way.”
Freeing the flow of rivers also benefits the environment; it improves the movement of fish and other aquatic life necessary for healthy rivers. Removing dams can also keep nutrients from farm runoff, the pollutants that plague a lot of Iowa’s waterways, from settling.
A big part of Biden’s original infrastructure framework was funding for updating and improving or replacing existing infrastructure. Hoogeveen said the state has used federal funds in the past, mostly through the U.S. Fish and Wildlife Service and the Department of Transportation.
He said he would have to wait for a final appropriation before he could say how Iowa might use federal money for managing dams.
“As your watershed gets larger, the river is supposed to be a river. It’s not really supposed to be something between a lake and a river,” Hoogeveen said. “It’s just not usually a very healthy place on the river. With the dams, it becomes this kind of slow, stagnant area where algae blooms become common.”
“When you get on to a much larger river, the net benefit for water quality is not to have a river dammed up.”
by Nikoel Hytrek