Abstract for: Impact of agriculture on nutrient pollution of the Potomac river: A case of animal farming in three counties

The Chesapeake Bay is the largest estuary and a critical natural resource in the United States, encompassing parts of six states and the District of Columbia. This critical natural resource is threatened by excessive nutrient loadings from non-point sources. Studies show that 78% of the annual nitrogen loads and 74% the phosphorus loads to the Chesapeake Bay is contributed from agriculture and urban non-point sources. Furthermore, 18% of the nitro¬gen and 27% of the phosphorus that enter the Chesapeake Bay annually comes from animal manure. In our current research, we assess the impact of agriculture on the nutrient pollution of the Potomac River, which is the second largest river that flows to the Bay. In particular, we study the impact of animal farming on the nutrient pollution that stem from three pilot counties (Frederick, St. Mary’s, and Shenandoah) of the Potomac watershed. Using CAST (Chesapeake Assessment Scenario Tool) as a source of data, we develop a system dynamics model that monitors the amount of manure generated from 12 different animals reared in the watershed, and how the manure generated in the watershed serves as both resource and liability in the watershed. We discuss potential policy options that could enhance the usability of animal manure and reduce its potential liability in the watershed.