Study Of Non-point Source Pollution Of The Small Watershed

With the growth of people’s environmental awareness and the increasing attentionof government to environment protection, the point source pollution of the water has beeneffectively prevented. The non-point source pollution turns to be the key problem of thewater pollution. In particular, because of the lack of information and the limit of theappropriate scope of the existing models, the non-point source pollution of manysmall watershed can’t be counted out and guided scientifically. This paper summarizescalculation methods of the non-point source pollution of small watershed in China; themethod based on the SCS distributed hydrological model is emphasized. The methed candivide the watershed, reflect the impact of land use, soil and antecedent precipitation, andreveal the spatial and temporal characteristics of the pollution. The export coefficientmodel of Yujia lake watershed is built and the method based on the SCS distributedhydrological model is also applied. Both results are compared and analyzed, indicating themethod based on the SCS distributed hydrological model is reasonable and practical. Thenon-point source pollution results based on the SCS distributed hydrological model areused to analyse the non-point source pollution load of Yujia lake watershed. The primarycoverage is as follows:The export coefficient model approach is used to count the amount of the non-pointsource pollution. And the SCS distributed hydrological model of Yujia lake watershed isbuilt and calculates the amount of the non-point source pollution withthe measured concentration data. Both results are reasonable and meet the accuracyrequirements.The spatial and temporal characteristics of the non-point source pollution load isanalyzed. Most of the non-point source pollution occurrs between April to July and thesouth of Yujia lake watershed is the key zone to the non-point source pollution.Several typical rainfall trends of Yujia lake watershed are summed up and theuncertainty of the non-point source pollution is analyzed. The worst rainfall trend isobtained.