Lake Waccamaw Hydrilla Management Project


Lake Waccamaw is one of the largest, roughly 9,000 acres, Carolina Bays in the Southeast. Carolina Bays contain unique ecosystems due to wetland isolation, which largely are fed by rain and shallow groundwater. Due to isolation, wildlife and other aquatic organisms have found that Carolina Bays provide optimal habitat for reproduction and survival. A change in ecosystem dynamics, such as an infestation of aquatic weeds, could disturb vital habitat for many species. The Aquatic Weed Control Program is protecting this vital ecosystem by continually monitoring and applying aquatic herbicides in the affected area.

History of the Lake Waccamaw Project

This project began due to citizen comments made to the N.C. Division of Water Resources (DWR) and State Park office about excessive growth of aquatic vegetation around the docks. During 2012, the DWR Aquatic Weed Control Program (AWCP) inspected and detected the presence of Hydrilla. Later, N.C. State University aquatic weed researchers conducted a lake-wide submerged aquatic vegetation (SAV) survey to determine the scope and magnitude of the Hydrilla infestation. The survey concluded that roughly 960 acres out of the 9,000 acres were infested with Hydrilla

During the Winter of 2012-2013, a technical advisory committee was created to make management recommendations based on the results of the lake-wide survey. They concluded that no triploid grass carp, a biocontrol, would be used. They also concluded that aquatic herbicide treatment should begin the following year. During the growing season of 2013, DWR contracted with SePro Corporation to design and implement an herbicide treatment. A treatment of slow-release fluridone pellets would be applied during the growing season to control the growth of Hydrilla.  After the growing season, another lake-wide SAV survey was conducted to assess the success of the treatment. This management strategy was used between 2013-2017. 

Current News

Due to the success of the herbicide treatment, the committee decided to reduce the amount of treatment area from 960 acres to 455 acres in 2018. This resulted in roughly 500 acres not included in the 2018 treatment area. During 2018, 455 acres were treated with slow-release fluridone pellets, while the 500 untreated acres were being monitored by the DWR AWCP. After the growing season, the AWCP found that no Hydrilla was detected within the untreated area. This management strategy was continued into 2019.