Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 11/15/2009
Publication Date: 8/15/2010
Citation: Fisher, T.R., Jordan, T.E., Staver, K.W., Gustafson, A.B., Koskelo, A.I., Fox, R.J., Sutton, A.J., Kana, T., Beckert, K.A., Stone, J.P., McCarty, G.W., Lang, M.W. 2010. The Choptank Basin in transition: Intensifying agriculture, slow urbanization, and estuarine eutrophication. In: Kennish, M.J. and Paerl, H.W., editors. Coastal Lagoons: Critical Habitats of Environmental Change. New York, NY: Taylor and Francis Group. p. 135-165. Interpretive Summary:
Technical Abstract: The Choptank basin and estuary are located on the Mid-Atlantic coastal plain on the Delmarva Peninsula. The regional hydrology is characterized by nearly uniform rainfall, but large seasonal variations in temperature and evapotranspiration (maximum in summer) drive large seasonal changes in groundwater and stream discharge (minimum in fall). Storm flows and groundwater recharge occur primarily from fall through spring, and average annual stormflows are determined by watershed slope. Water quality in non-tidal streams is largely determined by agricultural landuse and animal feeding operations, and N and P concentrations have been increasing for decades. Inputs from non-tidal streams, together with increasing human populations and wastewater discharges, have resulted in degrading estuarine water quality, including increases in chlorophyll a in surface waters and declining oxygen in bottom waters. Attempts to reduce losses of N and P from agricultural areas have met with limited success. One targeted watershed in the Choptank basin (German Branch) showed stabilized concentrations of baseflow N a decade after extensive application of some BMPs, along with small decreases in baseflow P, in contrast to the nearby Greensboro watershed which was not targeted for BMPs and exibited increases in baseflow N and P. Another attempt to show an improvement in water quality due to increased stream buffers under the CREP program was unsuccessful, probably because new stream buffers represented only an additional 11% of protected stream sides. Despite management efforts to improve water quality in the region, little progress has been made. We explore the reasons for the lack of progress and make recommendations to improve water quality in the Choptank basin and the Mid-Atlantic region. Anthropogenically impacted systems such as the Choptank and Delmarva Coastal Bays require a more regulated approach at the watershed scale with long-term monitoring to improve water quality.