Mallin, M.A.; Turner, M.I.H.; McIver, M.R.; Toothman, B.R., and Freeman, H.C., 2016. Significant reduction of fecal bacteria and suspended solids loading by coastal best management practices.
The Town of Wrightsville Beach, North Carolina, is a resort island that has periodic stormwater runoff problems, affecting local swimming and shellfishing waters from excessive fecal bacteria loading. In 2013–15, the planning, installation, and before-and-after monitoring of several types of best management practices (BMPs) designed to reduce pollutant loading to estuarine waters occurred. A straight pipe carrying runoff directly into estuarine Banks Channel was replaced by a buried infiltration chamber. The infiltration chamber did not reduce fecal bacteria concentrations but caused 93% stormwater discharge reduction, 96% fecal bacteria, 90% Enterococcus load reductions, and a 99% total suspended solids (TSS) load reduction to Banks Channel. Near the town's municipal area a number of curb cuts, reversed stormwater inlets, and regraded grassed swales were constructed to encourage infiltration of stormwater into the sandy soils of the island. Also in that area a large rain garden was constructed to collect and infiltrate stormwater that formerly drained directly into estuarine Lee's Cut. The set of stormwater volume reduction and treatment BMPs in the municipal area caused fecal coliform bacteria and Enterococcus concentration reductions of 57% and 71%, respectively, 50% stormwater discharge reduction, 28–55% fecal bacteria load reductions, and 99% TSS load reduction. The pollutant concentration and load decreases in the municipal area of Wrightsville Beach are particularly striking because the BMPs only capture about 50% of the runoff from the drainage area that enters the outfall into Lee's Cut. The BMPs installed and tested would be applicable to developed coastal areas in numerous locations.