Water Quality Issues and Nutrient Management in the Nanticoke Watershed

Abstract

Listen

Translate article

Water quality trends were monitored in eight subwatersheds in the Broad Creek watershed over a four-year period as best management practices (BMP's) were implemented. The BMP's consisted of nutrient management plans and construction of manure storage sheds. There were a total of 227 poultry houses in the subwatersheds. Nitrate concentrations were related to the percentage of cropland. The highest average seasonal nitrate concentration was 19.1 mg/L. There was no general decrease in nitrate concentrations over the four-year period. Average seasonal ortho phosphorus concentrations ranged from <0.010 to 0.19 mg/L. Introduction The Nanticoke River Basin of Delaware is located in the southwestern part of the State, with the major part of the watershed in Sussex County. The upper end of the Nanticoke Basin is located in Kent County. There are many small tributaries and ponds in the basin that drain into either the Nanticoke River or its major tributary Broad Creek. The river begins as freshwater, but eventually ends up as brackish water subject to tidal influence making them important estuary and spawning ground for fish. The centers of population in this basin include Seaford, Blades, Bridgeville, Greenwood, Laurel and parts of Georgetown. These towns have a combined population of 13,000 residences; with the rural population included, the basin has an estimated population of approximately 32,000. The State of Delaware owns several tracts of land in this basin (Nanticoke Wildlife Area, Owens State Forest, Ellendale and Redden Forest). Craigs and Portsville Ponds and the Nanticoke Wildlife area have direct and easy access for water based recreation. The Ellendale Swamp is located in this basin. The designated stream uses in this basin include ERES (Waters of Exceptional Recreational or Ecological Significance) use, primary contact recreation lakes and ponds, secondary contact recreation, and propagation of fish, aquatic life and wildlife. The drainage basin consists of 102,800 ha, with 51% of the total land area in agriculture. Other land use includes forestland 39%, brush land 5% and urban areas 2.4%. Geologically, the basin lies within the Atlantic Coastal Plain that consists of