Click on “Download PDF” for the PDF version or on the title for the HTML version.
If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.
Agricultural BMPs, Nutrient Load Reductions, and Watershed Restoration –The Octoraro Creek Watershed and the Chesapeake Bay
Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.orgCitation: Watershed Management to Meet Water Quality Standards and Emerging TMDL (Total Maximum Daily Load) Proceedings of the Third Conference 5-9 March 2005 (Atlanta, Georgia USA) Publication Date 5 March 2005 701P0105.(doi:10.13031/2013.18101)
Authors: John R. Shuman
The Octoraro Creek drains 208 square miles in Lancaster and Chester counties in Pennsylvania
and Cecil County in Maryland, and enters the Susquehanna River at the head of the Chesapeake
Bay. Land use is 75 percent agricultural, largely with Old Order Amish and English dairy
farming and swine farming. Streamflow data over the last 9 years shows no change in nitrate
concentrations in either branch of Octoraro Creek, with median nitrate concentrations in the 7.4
to 8.4 mg/L range. About 95 percent of the nitrates in Octoraro Creek are estimated to originate
from nonpoint sources. Streamflow nitrates are highest during baseflow periods in winter, when
biological uptake and denitrification rates are reduced. Nitrate concentrations in groundwater are
also elevated, with the watershed being the epicenter in Pennsylvania for high groundwater
nitrates. These high nitrate concentrations pose public health, herd health, and economic issues
in the watershed.