中文摘要：

利用1965-2006年共6个时相的遥感影像以及1918年地形图进行解译，获得了共7个时相的上海市中心城区水系分布数据．基于GIS和空间分析技术分析了近百年来上海市中心城区水系的演变过程及环境效应，研究结果表明：（1）1918～2006年，上海市中心城区河道数由1018条减少到184条，水系面积从37．68km^2减少到15．26km^2；（2）水系减少呈从中心向周边逐步发展的趋势，水系形态特征变化主要表现为河道裁弯取直、填堵等；（3）城市建设如开发区和住宅区的建设、修建道路和耕地整理等人为原因是造成水系演变的主要驱动力；（4）水系演变使上海市中心城区河网调蓄能力降低，减弱热岛效应能力变差．根据研究结果，对未来水系规划提出了建议．

英文摘要：

Using the topographic data of 1918 and 6 remote sensing images in different times from 1965 to 2006, 7 urban river distribution maps of downtown Shanghai were derived in this research. The spatio-temporal evolution of urban river system and its impacts on the environment were analyzed based on GIS and spatial analysis techniques. The main results include： （1） From 1918 to 2006, the quantity of rivers in downtown Shanghai has decreases from 1 018 to 184, correspondingly the areas of them have shrunk from 37.68 km2 to 15.26 km2. （2） The ＇meandercutoff and obstruction of river are two major manners of the river system reduction. And the trend of urban river system diminishment is from the center to the surrounding. （3） The primary driven force of urban river system evolution is human activity, such as constructions of buildings and roads, and cropland degradations. （4） The evolution of urban river system disrupts the system＇s water storage capacity, and weakens its urban heat island effect. Based on the analysis, several suggestions were proposed for the future planning.