After White Clay Creek in Delaware was designated as one of the United States’ National Wild and Scenic Rivers in the 1990s, the National Park Service established a restoration committee with the goal of bringing the river back to life. One recommendation the committee made was to remove the seven dams along the river.
Fast forward to December 2014 and the first dam along the waterway, Byrnes Mill Dam, was breached. Construction workers operating with supervision of hydrologists at the University of Delaware took out the middle 40 feet of the dam, opening up a valuable stretch of White Clay Creek to anadromous fish spawning that will help improve game fish populations as well as ecosystem health overall.
The project is Delaware’s first dam removal for fish passage.
“The main reason was to restore fish passage,” said Jerry Kauffman, principal investigator on the project and director of the Water Resources Agency, housed in the University of Delaware’s School of Public Policy and Administration. “There’s just an amazing amount of fish that spool in that stream. But there are water quality benefits as well by allowing waters to fluctuate naturally.” There are also some slight flood control benefits, says Kauffman, as the removal lets water in the stretch of river return to more natural levels.
Some of the fish species that will benefit from the dam breach include the American shad, hickory shad, river herring and striped bass. Those are some of the biggest targets that researchers will look at to assess the success of the project later on, says Kauffman. Fishermen, meanwhile, may be looking at the abundance of just a few species in particular.
“We hope that the American Shad comes back. It’s really the fish that most people identify with,” said Kauffman. “If we can get them available for recreational sport fishermen and get the shad going here, we can get an eco-tourism economy going here.” Stripers, of course, are an amazing sport fish, says Kauffman. And they’re probably the best tasting of the fish that will most benefit from the Byrnes Mill Dam breach.
Scientists at the school are looking to tag those and other fish with acoustic transmitters in the near future to judge how successful the dam project has been. The abundance counts that they collect will be compared to those before the dam was breached and show in no uncertain terms whether all the work was worth it.
“Our fish abundance surveys (before the dam breach) found thousands of anadromous fish downstream, but none upstream,” said Kauffman. “Based on our data so far, none have made it past the dam until now.”
The new passage will help those fish to make it upstream for spawning, while also improving parts of the river’s ecosystem overall. Threatened American eel will also benefit from the opened dam, as will predators who eat spawning fish like black bears and bald eagles. There are still six dams to go, says Kauffman, but the intent is to open up the waterway so that fish can make it all the way from the White Clay to Delaware Bay.
There were more than two dozen University of Delaware students who participated in some way, says Kauffman. Civil engineering students sampled and surveyed. Historical preservation students surveyed the dam’s construction and discovered that it was built during the American Revolution. And a few students have even gotten jobs working in dam removal after graduation.
“It wasn’t the objective to do it that way, but our funders mentioned that they really appreciate the educational and research benefits we provide,” said Kauffman. Those include the National Oceanic and Atmospheric Administration and American Rivers, a nonprofit conservation organization.