Researchers and Eno River State Park staff are taking an initial step to combat the invasive aquatic weed hydrilla there, launching a two-year pilot project to introduce an herbicide into the river.
The Eno River Hydrilla Management Task Force, representing several state agencies, approved installation of a mechanism near the park’s western boundary that gradually introduces the herbicide fluridone in hopes that it will be effective along a 16-mile downriver section. A contractor is supplying the herbicide in a concentration that is EPA-approved as safe for swimmers and boaters and non-toxic to fish and wildlife.
This marks the first time the herbicide is being used in a North Carolina river, although it has been used successfully at Lake Waccamaw State Park and Lake Gaston, Lake Tillery and Tar River Reservoir. After months of study and monitoring the river, the task force decided that pulling the weed by hand or introducing grass carp to consume hydrilla are not practical.
Hydrilla is a submersed aquatic plant that can create nearly impenetrable mats of stems and leaves on the surface of lakes, rivers and other waterways. An invasive species from Asia, hydrilla impedes recreational use of waterways, crowds out native vegetation and can ultimately harm fish and other aquatic species. The plant can also clog intakes where rivers or reservoirs are used for drinking water supplies and irrigation.
“This is a very real threat to the Eno River, both in terms of recreation and the vulnerable species in the waterway,” said Keith Nealson, Eno River State Park superintendent. “The Eno is not only a natural and cultural treasure for people in this region, but a bellwether for the health of the river basin, including Falls Lake and other sources of drinking water.”
Research by the task force and North Carolina State University suggests the hydrilla is spreading downriver at a rate of up to one mile a year and could soon become a serious nuisance in Falls Lake.