快速城市化地区土地利用变化及其对水质的影响——以上海市奉贤区为例

Land Use Change and Its Impact on Water Quality in the Rapidly Urbanized Area

对奉贤区位于城市化发展缓慢发展期、增长期和快速增长期3个时期的2000、2003和2008年土地利用数据分析发现,2008年城镇住宅用地、绿地和工业用地较2000年增长明显,分别上升至2.23%、4.82%和10.08%;农村生产用地和农村住宅用地占全区比例共下降了19.46%,说明奉贤区城市化对土地利用格局影响明显,城镇化建设使农村用地面积大大减少。主要水质指标CODmn、NH3-N和TP与不同半径缓冲区土地利用类型的相关性结果显示,其他建设用地、工业用地等与水质正相关关系显著,而绿地、农村生产用地与水质显著负相关。主要相关性在500 m以下比较明显,随着缓冲半径的增大水质与土地利用/覆盖变化相关性逐渐减弱,说明城市化带来土地利用巨大变化是影响区域河道水环境质量的重要原因。

According to the land use data of three urbanization stages of slow development,growth and rapid growth in 2000,2003 and 2008 in Fengxian District,the urban residential land,green space and industrial land in 2008 increased obviously respectively by 2.23%,4.82% and 10.08% in 2000;the proportion of rural production land and rural residential area decreased by 19.46%,indicating that the urbanization of Fengxian District had significant impact on its land use pattern and urbanization construction led to the large decrease of rural land area.As indicated by the correlation between the main water indexes of CODmn,NH3-N and TP and the land use type in the buffer area with different radius,other construction land and industrial land were positively correlated with water quality,while the green space and rural production area were negatively correlated with water quality.The radius of 500 m showed the most significant correlation.As the radius increased,the correlation between water quality and land use/coverage change gradually decreased.All these analysis told us that the land use pattern transition brought by urbanization was the main reason to the water pollution of rivers in the urban area.