On Jan. 23, the City of Wilmington re-stocked Greenfield Lake with 800 sterile grass carp to continue managing water quality in the lake. For the last several years, the city has used sterile carp fish to help control growth of underwater vegetation, which in turn helps reduce unsightly algae.
Algae is constantly growing at Greenfield Lake because of stormwater runoff that flows into the lake. The polluted runoff comes from the densely populated, 2,500-acre Greenfield Lake Watershed that includes a lot of paved surfaces such as parking lots and roads where rainwater can’t be absorbed into the ground. Most of the polluted runoff comes from the waste of pets and wildlife, fertilizers and yard waste such as leaves and grass clippings.
The city has worked to address the algae problems at Greenfield Lake in several ways, including installing aeration systems to help increase water circulation and using the sterile fish to eat underwater weeds and algae. The carp re-stocking has been permitted by the NC Division of Wildlife.