ANIMALWASTE BMP IMPACTS ON SEDIMENT AND NUTRIENT LOSSES IN RUNOFF FROM THE OWL RUN WATERSHED

Abstract

The results of the 10-year study conducted in the Owl Run watershed clearly indicate the beneficial impacts ofthe best management practices (BMPs) on the surface water quality. The main objective of the study was to determine theeffectiveness of a system of animal waste BMPs for improving surface water quality. Precipitation, streamflow, totalsuspended solids, nitrogen (N), and phosphorus (P) water quality parameters were measured at the main outlet and inthree subwatersheds. A pre- and post-BMP comparisons of annual water quality parameters were performed. Reductionsin all forms of N and most forms of P were observed due to the implementation of BMPs. For the average annual valuesat the main watershed outlet, BMPs were effective in reducing both loads and concentrations of all forms of N with thelargest reductions in soluble organic N (62%) and the smallest reduction for nitrate-N (35%). Furthermore, BMPs wereeffective 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. Thesystem of BMPs implemented in the Owl Run watershed was effective in reducing nutrient loadings, especially Nloadings. However, when P is the main water quality concern, implementation of P-based nutrient management plansshould be considered.