太湖流域土地利用变化及洪涝灾害响应

Flood response to land use change in Taihu Lake Basin

根据1986年和1996年土地资源调查和土地详查资料,分析了太湖流域土地利用的数量变化和空间变化,揭示了该区土地利用变化的幅度、速度、区域差异,以及土地利用变化的驱动力。根据1991年汛期(5～9月)降雨,分别计算了1986、1996年下垫面状况下的产水量,比较了二期产水数量和空间分布的差异,分析了20世纪90年代以来流域水位连续偏高的原因,进而分析洪涝是如何对土地利用的变化作出响应的。太湖流域土地利用变化的特征是耕地面积快速减少和建设用地迅速增加,土地利用变化的驱动力是政策因素、经济发展和人口增长。太湖流域10年间土地利用变化使流域产水量增加,洪涝过程缩短,增加的产水分布在流域的上游,加重了流域的洪涝灾害。

The Taihu Lake Basin is one of the most populous regions with fastest economic growth and most intensive land use in China.Based on detailed investigations of land use data and land use information in1986and1996,this paper analyzes the quantitative and spatial changes of the basin's land use as well as reveals its change range,speed,regional difference and driving force.Based on flood season precipitation(from May to September)of1991,this paper identifies the reasons for frequent high flood water level in Taihu Lake Basin by compar-ing different runoff-yields of1986,1996under various underlying surface conditions.The char-acteristics of land use change are reflected in the increase of construction area and the decrease of arable land area.The main drive forces of the land use change are aspects of policy,economic growth and increasing population pressure.Land use characters in Taihu Lake Basin are high in-tensive land exploitation,quickly land use changes and inadequate reserve land resources.The change of underlying surface not only increased runoff-yield but also affected the process of runoff-yield,merge and flow.The increase of land use for construction purpose made peak flood come more quickly and higher,and flood water trend to concentrate,which result in serious damage.In addition,the change of underlying surface will completely or partly change the rela-tionship between river and river,river and lake,lake and pond,and eventually affect the process of draining.