Simulation of Non-point Source Pollution Based on SWAT model - A Case Study of Ashi River Basin

摘要

The Soil and Water Assessment Tool (SWAT) model was examined for its applicability in modeling stream-flow and nutrients (total nitrogen, TN and total phosphorus, TP) in Ashi River Basin, China covering an area of 3545 km~2. This model was calibrated by using the observed data of monthly flow during 1996-2005 and nutrients (TN and TP) during 2006-2008, and validated by using the observed data of monthly flow during 2006-2010 and water quality during 2009-2010. For stream-flow, the monthly results of RE, R~2 and Ens values reached 6.42%, 0.61 and 0.59 respectively for calibration period, whereas these were -12.83%, 0.69 and 0.67, respectively for validation period; for TN calibration, values of RE, R~2 and E_(NS) were -18.33%, 0.64 and 0.55 respectively, and for validation period they were -17.34%, 0.68 and 0.57 respectively; for TP calibration, values of RE, R~2 and Ens were -4.32%, 0.61 and 0.56 respectively, and for validation period they were -18.02%, 0.67 and 0.58 respectively. Results show that SWAT has applicability in modeling stream-flow and nutrients (TN and TP) in cold and flat area.