| The suitable export coefficients of NH+4-N, TP and COD for Fenghe River watershed in Shaanxi Province were determined by comparing the load given by improved export coefficient model with that calculated by the mean concentration method based on measured data at Qinduzhen section from 2001 to 2009. The results showed that the export coefficient model considering the transport lose in watershed had low relative error, less than 15% for COD load, 13% for TP and 14% for NH+4-N load. That was to say, the given values of the export coefficients and transport lose parameter were suitable for this watershed. The sources of the non-point pollution in Fenghe River watershed were analyzed with export coefficient model considering the transport lose, and it could be concluded that the domestic pollution of local people and cultivated land has great contribution to non-point pollution, and there was an roughly increasing trend in the last ten years. In detail, the cultivated land accounted for 37.87%, 37.74% and 15.56% of non-point TN, NH+4-N and TP load in this watershed respectively, and domestic pollution contributed 40.73%, 41.06%, 61.19% and 21.98% to non-point TN, NH+4-N, TP and COD load respectively. In addition, Livestock breeding produced the non-point load for COD as high as 73.49%. Therefore, the control and management of pollution from cultivated land, domestic sewage and livestock breeding could effectively reduce the output of non-point source load in this watershed. |
