岷江流域土地利用结构对地表水水质的影响

当点源污染得到有效控制时，非点源污染，尤其是农业非点源污染将成为影响地表水水质的主要因素。利用遥感和地理信息系统技术获取岷江流域土地利用类型，并在分析该流域内地表水水质监测数据的基础上，研究了不同土地利用结构与地表水水质的相关关系。结果表明，在以单一土地利用类型为主控制的区域中，林地和草地控制的小流域的地表水水质明显优于耕地；在不同土地利用类型的组合结构中，地表水水质的优劣状况介于林地、草地和耕地为主控制的小流域之间；在其他条件相似时，随着小流域内林地和草地比例的增加，非点源污染降低，而随着耕地比例的增加，非点源污染有增大的趋势。此外，土地利用结构对地表水水质的影响不仅表现在数量结构上，同时表现在空间分布上.

EFFECTS OF LAND USE STRUCTURE ON SURFACE WATER QUALITY IN MINJIANG RIVER BASIN

As point source pollution has been effectively controlled,non-point source pollution,especially which of agriculture,will become the main factor affecting the surface water quality.This paper investigated the relationship between the land use structure and the surface water quality of Minjiang River Basin by using remote sensing and geographical information system to retrieve the land use type and on the bases of analyzing the monitoring of surface water quality in the basin.The results of this study indicate that a) In the watersheds which are controlled mainly by a single land use type,the surface water quality of woodland and grassland-controlled watersheds is distinctly better than that of watersheds controlled by farmland;b) In the combined structure of different land use types i.e.woodland,grassland and farmland,the concentration of pollutants is in the middle of the watersheds which are controlled primarily by woodland or grassland and those controlled by farmland;c) When other conditions are similar,the concentration of non-point source pollution decreases according to the increase of the area of woodland and grassland,while increases with the increase of the area of farmland in the watersheds;d) Effects of land use structure on non-point source pollution are also reflected on the spatial distribution of the pollutants besides amount structure.