A task force of federal, state and local officials will hold a public information meeting in Hillsborough on Wednesday to describe a two-year project to use an herbicide to kill the invasive plant hydrilla in a section of the Eno River.
Hydrilla is a submerged spiny plant from Asia that grows in tight mats, becoming a nuisance for boaters, swimmers and recreational fishermen. It often suffocates native vegetation and animals such as mussels, snails and fish and can clog intake pipes for drinking water and irrigation.
The Eno River Hydrilla Management Task Force plans to begin using a federally approved herbicide within Eno River State Park this summer and to monitor its effectiveness against hydrilla. The plant was first discovered in the park in 2005, and the task force was formed to study and combat it two years later.
Removing the plants by hand doesn’t work well, because hydrilla grows so fast, Rob Emens, manager of the aquatic weed control program with the N.C. Department of Environment and Natural Resources, said last fall. Emens noted that Eno River State Park organized a volunteer project to weed out a section of the Eno in 2011 but that a month later the river was inundated again.
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Hydrilla was initially brought to the United States as an aquarium plant and was first discovered in the wild in North Carolina in Wake County’s Umstead State Park in 1980. It later appeared in Lake Orange and West Fork Eno Reservoir before moving downstream into the Eno River as far as U.S. 501.
The plant spreads from one body of water to another primarily when fragments get caught on boats and trailers and moved.
Researchers at N.C. State University and the N.C. Division of Parks and Recreation estimated last fall that the Eno hydrilla infestation is spreading downriver at a rate of up to one mile per year and that the plant could begin to hamper boating and other recreational activities in Falls Lake in about 12 years.
The city of Raleigh is watching hydrilla’s movement toward Falls Lake, which is Wake County’s largest source of drinking water. City officials say their intake pipes are 40 feet deep, below where the plant flourishes, and shouldn’t get clogged.
Before settling on herbicides, the task force has considered other remedies, including introducing grass carp, which have helped in West Fork Eno Reservoir. Herbicides have been used to control hydrilla in many lakes in the state but have not been used in a river like the Eno, according to an environmental assessment done for the task force.
The Eno River Hydrilla Management Task Force will hold an informal, open house-style meeting at 6 p.m. on Wednesday in Conference Room 230 in the Whitted Building at 300 West Tryon Street in Hillsborough.