[Effects of parameter spatial distribution on non-point pollution source model].

The SWAT model was used to simulate the effects of parameter spatial distribution on flow and nutrients loadings in the Daning river watershed. It was first calibrated and validated using the measured data for the period of 2000 - 2004. Then the model was used to simulate the effects of watershed delineation scenarios on flow and nutrients loadings, using six watershed delineations, each with a different number of sub-watersheds. The max relative error is 19.6% for the annual mean flow under different watershed delineation scenarios. The flow increase first and then decrease with the number of sub-watersheds. The efficiencies coefficient is 0.52 - 0.82 for annual mean flow and 0.80 - 0.83 for monthly mean flow under six delineation scenarios. Outlet nutrients simulations are slightly affected by changes in watershed delineation scenarios. The relative errors of organic nitrogen and organic phosphorous are 16.2% and 7.7% respectively and no explicit trend is observed.