[Effect of land use/cover change on pollution load of non-point source in upper reach of Yangtze River Basin].

ABSTRACT

On the basis of other scholars' researches, utilizes export coefficient model, adopts RS and GIS techniques, estimates the non-point source (NPS) pollution load of upper reach of Yangtze River Basin, and simulates its special distribution. The results indicates that the total nitrogen load caused by land use drop from 1.23 x 10(6) tons in 1970s' to 1.16 x 10(6) tons in 2000 on the premise of taking no account of basin loss. It reduced year by year basically in the past several decades and so did TP load which decreased from 3.7 x 10(4) tons in 1970s' to 3.5 x 10(4) tons in 2000. As far as province, land use and water system are considered, Sichuan province, crop land grass, Jinsha river and Jialing river are important contributories of NPS pollution load in study area. Intensity analysis shows the region of Chongqing municipality and the watershed of Jialing River are two highest NPS pollution load areas, and these areas should be gained more attention in the future. Using the method put forward in this paper, NPS pollution space simulation is carried out in large scale basin such as upper reach of Yangtze River Basin precisely basically.