云蒙湖流域非点源磷污染时空变化研究

Spatio-temporal Change of Non-point Source Phosphorous Pollution in Yunmeng Lake Watershed

运用输出系数模型,在GIS&RS支持下,对云蒙湖流域非点源磷污染进行了时空动态模拟。结果表明,1986—2010年,云蒙湖流域非点源磷污染负荷量明显增加,1986、1995与2010年TP负荷量分别为100.98,123.57,144.36t;从空间分布来看,TP高负荷区主要分布于流域的河谷低平地带,主要是由于该区集中了大部分农业耕作区,化肥施用量高;从土地利用类型来看,耕地非点源污染TP逐年增加,其贡献率也逐年增加,由1986年的89.5%,1995年91.35%上升至2010年92.02%,林地、草地TP变化较小,贡献率呈减小趋势,居民用地TP增加幅度大,但由于面积较小,其贡献率较小;对于子流域而言,耕地面积比例高的子流域,TP负荷强度增加程度较大,TP负荷强度较大的子流域逐渐由中东部地区向全流域扩展。

Export coefficient mode was used to analyze the spatio-temporal changes of the non-point source（NPS）phosphorous pollution based on GISRS.The result indicates that the TP load caused by land use increased from 100.98tin 1986,to 123.57tin 1995,to 144.36tin 2010;as far as spatial distribution of the TP load is concerned,the high phosphorous load mainly distributes in the flat River Valley,because there are many farm lands distributed in that region.As for land-use type,different land uses have different contributions to the total non point source pollution load,the TP from farm-land increased year by year,the contribution rate,is 89.5%in 1986,91.35%in 1995and 92.02%in 2010,the load of the forest-land and the grass-land had a little change,but the contribution rate decreases gradually,the residential load increases by a large margin,however,the contribution rate is very little.In the term of the sub-basin,the higher the proportion of the farm-land is,the more the TP load increases,the high TP load of the sub-basin expands from the eastern and central region to the whole watershed.