Municipal and industrial wastewater have created local problems, including eutrophication, plant nutrient loss, discharge-induced die-off of algal flora, and changes in chemical and biological character. Among methods used to solve these problems is that of overland runoff, and the project is an attempt to incorporate this method into an estuarine environment. A site in the subtropical coastal marsh at Dulac, Louisiana, home port facility for a menhaden processor, was selected: an artificially enclosed freshwater marsh, totaling about two and one-half square miles.