Nitrogen TMDL development in the Neuse River Watershed: An imperative for adaptive management

Abstract

The Neuse River estuary in North Carolina (Figure 1) is a typical example of a stressed coastal system. The estuary has been experiencing characteristic symptoms of nutrient overload including excessive algal blooms, low levels of dissolved oxygen, large fish kills, and outbreaks of toxic microorganisms (Burkholder et al., 1995; Paerl et al., 1998). These problems have been attributed to the high nutrient loading that generally results from the kinds of changes that have occurred in the watershed over the past several decades (NC Senate Select Committee on River Water Quality and Fish Kills, 1996; McMahon & Woodside, 1997) . The upper portion of the Neuse River drainage basin includes much of North Carolina’s Research Triangle (defined by the cities of Raleigh, Durham, and Chapel Hill), an area that has experienced economic prosperity and rapid population growth since the 1970s. Population expansion and development are also occurring in lower portions of the basin with an increasing coastal population and a growing commercial hog-farming industry. Municipal wastewater treatment plants, urban runoff, and confined animal feeding operations, together with agricultural fertilizers, are considered to be major sources of nutrients in the Neuse watershed.