Abstract:

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.〖

Key words: land use structure, surface water quality, nonpoint source pollution, GIS, Minjiang River〖