太湖流域土地利用变化对非点源污染负荷量的影响

以水环境问题严重的太湖流域为研究区,通过选取1985年和2000年的TM/ETM土地利用解译数据,分析其土地利用变化的模式,应用L-THIA（Long-Term Hydrologic Impact Assessment）水文模型,模拟不同时期土地利用条件下径流量与营养盐负荷的变化.结果显示,2000年与1985年比较,土地利用变化表现为城镇用地向耕地扩张,由此导致年平均径流量增加2.79%;城镇用地的TN和TP分别增加467.952 t和30.587 t,耕地的TN、TP的减少量分别为384.885 t和30.112 t;林地的TN、TP有少量增加,分别增加了3.437 t和0.093 t;整个太湖流域的TN、TP分别增加了86.503 t,0.568 t.受土地利用变化分布特征的影响,苏锡常区、湖西区和浦东浦西区TN、TP负荷量变化最为显著,其城镇用地TN、TP分别增加了37.10%、34.81%和24.3%.

The Impact of Non-point Pollutant Load of Land-use Changes in Taihu Basin

This paper selects Taihu basin as a study area, with serious water pollution. Historical land-use scenarios for 1985, 2000 are analyzed to track the changes of land-use by interpreting TM/ETM image. The changes of runoff volume and non-point nutrient load are simulated due to land use change by using L-THIA (Long-Term Hydrologic Impact Assessment) model. The results express that there is a significant increase in urban and residential area by occupying farm land between 1985 and 2000, which leads to about 2.79% increase of the surface runoff volume in the whole watershed. The loads of total N and total P increase 467.952 t and 30.587 t respectively under urban and residential land use, decrease 384.885 t, 30.112 t for farm land, and increase 3.437 t, 0.093 t for forest land. For the whole study area, the loads of total N and total P increase 86.503 t, 0.568 t respectively. Non-point pollutant load response varies with the extent of land use changes in different parts of the basin, and in Suxichang, Huxi and PudongPuxi sub-regions, where the urban area increases more largely, the loads of total N and total P of urban and residential land use increase about 37.10%, 34.81% and 24.34% respectively.