Animal Waste Bmp Impacts on Sediment and Nutrient Losses in Runoff from the Owl Run Watershed

The results of the 10-year study conducted in the Owl Run watershed clearly indicate the beneficial impacts of the best management practices (BMPs) on the surface water quality. The main objective of the study was to determine the effectiveness of a system of animal waste BMPs for improving surface water quality. Precipitation, streamflow, total suspended solids, nitrogen (N), and phosphorus (P) water quality parameters were measured at the main outlet and in three subwatersheds. A preand post-BMP comparisons of annual water quality parameters were performed. Reductions in all forms of N and most forms of P were observed due to the implementation of BMPs. For the average annual values at the main watershed outlet, BMPs were effective in reducing both loads and concentrations of all forms of N with the largest reductions in soluble organic N (62%) and the smallest reduction for nitrate-N (35%). Furthermore, BMPs were effective in reducing both loads and concentrations of most forms of P with the largest reductions in particulate-P (78%) and the smallest reduction for soluble P (39%). However, BMPs were not effective in reducing orthophosphorus-P. The system of BMPs implemented in the Owl Run watershed was effective in reducing nutrient loadings, especially N loadings. However, when P is the main water quality concern, implementation of P-based nutrient management plans should be considered.