Modelling of point and non-point source pollution of nitrate with SWAT in the river Dill, Germany

摘要

We used the Soil and Water Assessment Tool (SWAT) to simulate point andnon-point source pollution of nitrate in a mesoscale mountainous catchment.The results show that the model efficiency for daily discharge is 0.81 forthe calibration period (November 1990 to December 1993) and 0.56 for thevalidation period (April 2000 to January 2003). The model efficiency formonthly nitrate load is 0.66 and 0.77 for the calibration period (April 2000to March 2002) and validation period (April 2002 to January 2003),respectively. However, the model efficiency for daily loads is low (0.15),which cannot only be attributed to the quality of input data of point sourceeffluents. An analysis of the internal fluxes and cycles of nitrogen pointedout considerable weaknesses in the models conceptualisation of the nitrogenmodules which will be improved in future research.