Endangered Fish Returns to 10-mile Reach of the Deep River after Dam Removal
Carbonton, NC – September 6, 2007– Restoration Systems, L.L.C., an environmental restoration and mitigation firm in Raleigh, North Carolina, has reported an extraordinary occurrence in Central North Carolina‘s lazy and historic Deep River. The Cape Fear shiner, a federally Endangered Species thought to be headed for extinction, has repopulated nearly ten miles of the restored river following the company’s 2005 removal of the Carbonton Dam.
Scientists from The Catena Group, an ecological consulting firm under contract to Restoration Systems to monitor progress in the restored river, discovered several groups of the sensitive fish distributed throughout a reach of the now free-flowing Deep River that was formerly impounded behind the dam. The former dam and more than ten miles of backwater served as a barrier, which isolated populations of the shiner known to occur below the dam and at locations well above the upstream limit of the former impoundment (more than ten miles upstream). Now it is reasonable to expect two-way genetic exchange among the several groups that presumably were isolated from each other for so many years.
The shiner has been in steady decline in recent decades, likely a result of the loss or reduction of suitable habitats in the region. Restoring appropriate habitat and encouraging the recolonization of the species was a central goal of the dam removal project.
Dr. Adam Riggsbee, an environmental scientist with Restoration Systems, and dam removal authority, says rivers can restore themselves when the appropriate dams are removed, bringing large-scale improvements to aquatic ecosystems, such as those now documented at Carbonton.
“The Carbonton Dam was selected from many candidates because it provided the hope of returning unequivocal ecological improvements when removed, which apparently it did,” says Riggsbee. “As far as we can determine, the documented recolonization of a federally Endangered Species following dam removal is unprecedented.”
The dam removal was paid for by the Ecosystem Enhancement Program, an initiative of the N.C. Department of Environment and Natural Resources. This innovative state program is responsible for the acquisition and implementation of mitigation projects resulting in environmental improvement “credits” from private providers to offset unavoidable public and commercial impacts to natural areas.
In order to generate environmental improvement credits, the project is required to produce demonstrable enhancements to water quality and in-stream habitat for common and endangered aquatic species. Project monitoring was initiated prior to dam removal to document baseline conditions. Monitoring activities documenting the progress of restoration are currently ongoing. In addition to fish, monitoring efforts are targeting freshwater mussels, aquatic insects, overall habitat and water quality. Fifty-eight “stations” along a 25-mile stretch of the Deep River and its tributaries were established to monitor the restoration over the course of five or more years.
Prior to the documented recolonization of the endangered shiner, the fish was known to inhabit only four locations elsewhere in North Carolina. Dam construction in the Cape Fear watershed, culminating in the Randleman Dam this decade (the fourteenth dam on the Deep River), had severely limited the available habitat.
“The Carbonton removal,” said project manger and company principle George Howard, “was intended as a demonstration project. We are hopeful the good news on the shiner will open some eyes to the importance of dam removal over traditional stream restoration methods, as some regulatory agencies are considering drastic reductions in the utility of this approach.”
Restoration Systems has built a multi-acre public park on the banks of the Deep River at Carbonton adjacent to the former dam site. The park and historic powerhouse are being transferred to the Deep River Parks Association this month along with funds for improvements and care as public facilities. Restoration Systems has also made a large contribution to the University of North Carolina-Chapel Hill, which was used to support graduate research on the Deep River resulting in peer-reviewed scientific publications.
The project team assembled by Restoration Systems consisted of engineers (Milone & MacBroom, an engineering firm based in Connecticut), general ecological expertise (EcoScience Corporation, multi-disciplinary environmental consultant in Raleigh, NC), aquatic biology specialists (The Catena Group in Hillsborough, NC) and an experienced ecological contractor to take down the dam (Backwater Environmental in Pittsboro, NC).
For more information on the Cape Fear shiner, visit the U.S. Fish and Wildlife Service’s website at www.fws.gov/nc-es/fish/cfshiner.html.
Kristen M. Poillon