Treatment to Manage Invasive Plant Resumes in Eno River

Monday, May 13, 2024
Hydrilla covering much of the surface of the Eno River in 2017. Hydrilla blocks sunlight, killing native plants below the surface and decreasing oxygen in the water.

Updated at 10:12 a.m. on May 15, 2024: To note that the start of treatment has been delayed due to recent rainfall.

Herbicide treatment to reduce an invasive aquatic plant in the Eno River will begin Wednesday, May 15, and continue through August.

The herbicide fluridone is being applied in a concentration well below limits set by the Environmental Protection Agency and is safe for humans, fish and wildlife. Property owners adjacent to the treated section of the river should take caution regarding the use of river water for irrigation during treatment for the Asiatic plant hydrilla.

A study using the herbicide has shown a significant reduction of the plant without impacts to the rest of the ecosystem or to human health. Hydrilla grows rapidly, creating thick mats on the surfaces of lakes, rivers and other waterways. It negatively affects the health of fish and wildlife in the area. Hydrilla also can clog intakes for supplying drinking water and irrigation. 

Sixteen miles of the Eno River are treated annually, from below the Ben Johnston Lake dam in Orange County to Roxboro Road/U.S. 501 in Durham County.

Hydrilla was discovered in the Eno River watershed in the early 1990s in Lake Orange, which is upstream of Hillsborough. In 2009, biologists confirmed hydrilla in the town’s West Fork Eno Reservoir. The N.C. Division of Water Resources addresses the hydrilla threat in both reservoirs.

The town is helping to fund the treatment in the Eno River, and Stormwater and Environmental Services Manager Terry Hackett is a member of the Eno River Hydrilla Management Task Force.

For more information, contact Hillsborough’s stormwater and environmental services manager by email or by phone at 919-296-9621. 

Related documents

Document Hydrilla: An Invasive Plant Threatening Waterways