Assessing Phosphorus BMP Effectiveness in the Cannonsville Watershed Using SWAT 2000

Assessing best management practice (BMP) effectiveness in large basins is complicated by hydrologic variability, ecosystem complexity, and issues of scaling. A traditional approach to assessing BMP effectiveness in large watersheds is to forecast several BMP scenarios and compare their performance relative to a baseline scenario. While this approach may provide insight into the effectiveness of future BMP scenarios, it does not quantify the impact of BMPs that have already been implemented. The authors propose that a continuous water quality model may be used as a pseudo-control watershed in order to determine BMP effectiveness in large catchments. Preliminary results using this approach suggest that agricultural BMPs have reduced dissolved phosphorus loads to the Cannonsville Reservoir in Upstate New York. Future work will involve the implementation of sophisticated analyses to confirm the statistical significance of reductions in dissolved phosphorus loads to the reservoir.