IMPORTATION LOADS OF NON-POINT SOURCE NITROGEN AND PHOSPHORUS IN THE THREE GORGES RESERVOIR

To understand the formation and change of non-point source pollution is the first important step to controll and manage non-point source pollution.There is a wide range of non-point source pollutants in the Three Gorges Reservoir.Every year,non-point source pollutants discharged into rivers from the upper reaches contribute the major part of non-point source pollutants in the Three Gorges Reservoir.In order to study the pattern of change in non-point source pollutants in the Three Gorges Reservoir,the model of non-point source pollution load from the upper basin of Chongqing Cuntan section of the Yangtze River was established on the basis of the SLURP model and the Export Coefficient Approach.At last,using the established model,non-point source TN and TP annual load from upper basin of Cuntan section were calculated and simulated for the period from 1996 to 2002.Except the more than 50% calculation error for non-point source TP load in 1998,all other calculation errors were less than 30%.It is considered that the model can provide a good fit to the observed data,and that the established model for non-point source pollution and its application in the Yangtze Basin will be valuable for the management and control of non-point source pollution,and may form a base for making policies on pollution control.