Delaware Administrative Code
Title 7 - Natural Resources and Environmental Control
5000 - Division of Watershed Stewardship
7400 - Watershed Assessment Section
7406 - TMDLs for Nutrients for the Nanticoke River And Broad Creek
Section 7406-1.0 - Introduction and Background

1.1 Intensive water quality monitoring performed by the Department of Natural Resources and Environmental Control (DNREC) and studies performed by others have shown that the Nanticoke River and Broad Creek are highly enriched with the nutrients nitrogen and phosphorus. Although nutrients are essential elements for both plants and animals, their presence in excessive amounts cause undesirable conditions. Symptoms of nutrient enrichment in the Nanticoke River and Broad Creek have included frequent phytoplankton blooms and large daily swings in dissolved oxygen levels. These symptoms threaten the future of the Nanticoke River Subbasin - very significant natural, ecological, and recreational resources of the State.

1.2 A reduction in the amount of nitrogen and phosphorous reaching the Nanticoke River and Broad Creek is necessary to reverse the undesirable effects. These nutrients enter the rivers from point sources and nonpoint sources. Point sources of nutrients are end-of-pipe discharges coming from municipal and industrial wastewater treatment plants and other industrial uses. Nonpoint sources of nutrients include runoff from agricultural and urban areas, seepage from septic tanks, and ground water discharges.

1.3 Section 303(d) of the Federal Clean Water Act (CWA) requires States to develop a list (303(d) List) of waterbodies for which existing pollution control activities are not sufficient to attain applicable water quality criteria and to develop Total Maximum Daily Loads (TMDLs) for pollutants of concern. A TMDL sets a limit on the amount of a pollutant that can be discharged into a waterbody and still protect water quality. TMDLs are composed of three components, including Waste Load Allocations (WLAs) for point source discharges, Load Allocations (Las) for nonpoint sources, and a Margin of Safety (MOS).

1.4 DNREC listed the Nanticoke River and Broad Creek on the State's 1996 and 1998 303(d) Lists and proposes the following Total Maximum Daily Load regulation for nitrogen and phosphorous.