Uncertainty Evaluation of Best Management Practice Effectiveness Based on the AnnAGNPS Model

Uncertainty of best management practice (BMP) effectiveness is an important factor in the development watershed plans. This study explored uncertainty BMP reducing total nitrogen (TN) load owing to hydrological parameters, thereby improving their reliability. A model, annualized agricultural non-point source pollution (AnnAGNPS), was employed evaluate four potentially feasible BMPs (i.e., riparian buffer, fertilization reduction, no-tillage, and parallel terraces) Shanmei Reservoir watershed, located southeastern coastal region China. Annual seasonal variations were evaluated based on ten parameter sets selected from 1000 groups using Latin hypercube sampling. The results showed that TN larger than simulation at annual time scales. tended be higher summer other seasons. varied seasonally, it always lower for most BMPs. indicated impact more effective, with a reduction rate summer. Among BMPs, terrace effective measure since had highest relatively low uncertainty. Although this case study, can provide scientific reference decision-making uncertain situations when AnnAGNPS applied water quality simulations.