【摘要】 在分析洮儿河流域上中游地区1970—2000年土地利用变化的基础上,利用长期水文影响模型估算研究区内非点源污染物的输出负荷,分析其空间分布特征,并引入单位贡献指数分析不同土地利用类型对不同污染物的影响程度。结果表明:(1)在这30a间,研究区的土地利用以草地、林地和农业用地为主,土地利用结构变化特征显著,生态用地面积大幅度减少,非生态用地面积迅速增加,研究区内人类活动增强并有加剧生态退化的趋势;(2)在这30a间,研究区内非点源污染负荷总量从3 400t上升到6 200t,总氮(TN)、总磷(TP)的高负荷分布区域主要集中在中游,并有向上游扩张的明显趋势;(3)采用贡献率和单位贡献指数(UCI)2个指标分析不同土地利用类型对非点源污染物TN,TP的影响,UCI能更好地反映土地利用对非点源污染的影响,其中农业用地对非点源污染的影响程度最大,住宅用地和工业用地次之,林地和草地影响最小。更多还原

【Abstract】 Land use patterns from 1970 to 2000 were analyzed to determine the changes in the study area.On this basis,long-term hydrologic impact assessment(L-THIA) model was used to evaluate the long-term average non-point source(NPS) pollution loads and to simulate their spatial distributions.Unit contribution index(UCI) was introduced to assess the impacts of various land-use categories to annual average NPS pollutant production.The results are as followed.(1) From 1970 to 2000,farmland,forest and grassland were the primary land use types in this area;ecological land area decreased dramatically with rapidly increased non-ecological lands,implying intensified human activities and the tendency of ecological recession.(2) During the past 30 years,NPS pollution loads rose from 0.34 million tons to 0.62 million tons;the areas of high TN and TP loads distributed mainly in the middle reach but has expanded to the upper reach considerably.(3) Contribution rate(CR) and UCI were calculated to analyze the relationship between land use types and NPS pollution,with UCI reflecting more closely the impacts of land use change to NPS pollution.Farmlands had the most significant impact on NPS pollutants and were identified as the main source,followed by residential and industrial lands,and forest and grasslands.更多还原