土地利用结构变化对非点源污染的影响研究

目前,应用模型对非点源污染进行时空模拟是非点源污染研究的重要方向,而输出系数模型在我国中、大尺度流域的非点源污染负荷研究时表现出独特的优越性。文章通过洪湖地区为例,利用输出系数模型,结合GIS技术,模拟洪湖地区污染物负荷空间分布及估算污染物总负荷。结果表明:(1)非点源污染高负荷区占洪湖市大部分面积,主要是农业耕作区带来的面源污染;沿路以及沿湖一带林地、草地为非点源污染低负荷区,这部分面积占洪湖总面积较少。(2)1995-2000年5年中耕地对TN的贡献率下降0.19个百分点,对TP的贡献率下降0.15个百分点,城镇用地对TN的贡献率上升0.18个百分点,对TP的贡献率上升0.13个百分点,林地和草地的贡献率略有上升,这与耕地面积减少,建设用地的不断扩张有关。(3)耕地对TN、TP贡献率在各种土地利用类型中占主导地位,贡献率其次为城镇用地、未利用地、林地、草地。

Impact of Land Use Change on Non-point Source Pollution in Honghu Area Based on Export Coefficient Model

Currently,temporal-spatial simulation of non-point source pollution by models is the mainstream of researches on non-point source pollution,and export coefficient model fully demonstrates the superiority of researches on estimating polluting load of non-point source pollution in the watersheds of medium-scale and large-scale in Chinese.Utilizing export coefficient model and adopting GIS techniques,the authors estimated the non-point source pollution load of Honghu area.and simulated its spatial distribution.The results indicated as follows.The high load area of non-point source pollution accounts for most of the area of Honghu,which is caused by agriculture.From year 1995 to 2000,farmland's contribution ratio to TN decreased by 0.19%,and that to TP decreased by 0.15%;urban land's contribution ratio to TN increased by 0.18%,and that to TP increased by 0.13%.Different land uses has various contributions to the total non-point source pollution load,the farmland's contribution ratio is dominant,and the gradation of contribution ratio to TN/TP is from farmland and urban land to forest and grassland.