基于土地利用变化的小江流域非点源污染特征

Effect of Land Use Change on Spatial-Temporal Characteristics of Non-Point Source Pollution in Xiaojiang Watershed

选取三峡库区典型支流——小江流域为研究对象,以GIS软件为分析工具,在L-THIA模型的基础上,分析小江流域非点源污染物负荷量随土地利用方式改变而产生的时空变化特征.结果表明:2007年小江流域非点源污染物TN和TP总负荷量分别为5563.11和1550.65t,其中旱地的污染物负荷量最大,TN和TP负荷量分别达到4633.43和1368.96t,占总负荷量的83.29%和88.29%;从空间分布上看,非点源污染主要集中在旱地较多的东河流域和南河流域;而从时间分布上看,随着旱地面积的大幅增加,1995—2007年小江流域污染物负荷量明显增加.

Based on the Long-term Hydrologic Impact Assessment （L-THIA） model and GIS technology, the effect of land use change on spatial-temporal characteristics of non-point source pollution load in Xiaojiang watershed, a typical tributary of the Three Gorges reservoir area, was analyzed. The results indicated that the annual non-point source pollution load of total nitrogen and total phosphorous in 2007 were 5563. 11 t and 1550. 65 t, respectively. Dry farm land was the largest pollution source with annual total nitrogen load and total phosphorous load of 4633.43 t and 1368.96 t, respectively, accounting for 83.29% and 88.29% of the total load. Furthermore, the East River watershed and South River watershed were the main output areas of pollution load, due to larger dry farm land. Additionally, the output of pollution load increased significantly with the growth of dry farm land area from 1995 to 2007.