城市透水面集水效益评价研究——以大连市为例

Benefits of Rainwater Retained by Urban Permeable Surfaces——A Case Study of Dalian City

透水面是城市雨水利用的重要手段。以大连典型市区——西岗区和中山区为研究区域,根据2005年航摄采集的基础数据统计了当年各类透水面的面积,进而根据当年的降雨量、地表径流的截留系数和地下水的下渗补给系数计算得出研究区域透水面的集雨量,然后根据相应的经济、生态效益指标计算了透水面的集水效益。研究结果表明:(1)透水面的总面积为3663.30hm2,占研究区域总面积的51.5%;林地、草地和透水路面的面积比为6.5∶1.3∶1.0。(2)研究区域林地、草地、透水路面对降雨径流的截流量为1.69×107m3,其中补充到地下水层的雨水量为5.0×106m3;合计产生经济效益1.4×106元,生态效益5.52×107元。同时,由于大连市透水面的发展控制了城市水土流失,营造了良好的人居环境,促进了该市的和谐发展,因而产生了显著的社会效益。

The urban permeable surface is an effective practice to conserve rainwater. This study presents a method to calculate the areas of the urban permeable surfaces and assess the benefits of the rainwater retained by them. As a case study in the Xigang District and the Zhongshan District of Dalian City,the areas of the urban permeable surfaces in 2005 were calculated based on the data from aerial photographic survey. Then the volume of the collected water in the year was obtained according to the annual rainfall amount,retaining ratio of the runoff,and infiltrating ratio of ground water. At last,the benefits of the rainwater retained by urban permeable surfaces were estimated using the economic and ecological benefit indexes. The main results from the study can be summarized as follows：（1） The total area of the permeable surfaces was 3 663.30 hm^2,which was 51.5% of the total area of the study region. The area ratio of forestry land,grassland,and porous pavement was 6.5：1.3：1.0. （2） In virtue of the urban permeable surfaces,runoff was reduced by 1.69×10^7 m^3,of which 5.0×106 m^3 rainwater infiltrated into groundwater layer. Consequently,the total economic benefit of the retained rainwater was 1.4×10^6 RMB and the ecological benefit was 5.52×10^7 RMB. Moreover,great social benefit was generated due to controlled soil erosion and improved urban residential environment.