中国城市LID技术设施的成本效益区域差异

Regional difference of cost effectiveness of low impact development(LID)technical facilities in Chinese cities

随着城市化进程不断加快,人口和城市规模不断扩张,对现代城市雨洪管理提出了新要求。本文运用情景分析法研究中国城市典型低影响开发(Low Impact Development,LID)技术设施的成本效益。分别以80%与95%降雨场次控制率对应的场次降雨为情景,以30年为服务期计算技术设施的雨水管理效益。研究发现:北方城市的建安成本与维护费用均值高于南方城市,同时受区域降雨量差异的影响,南方城市LID技术设施的雨水处理效益普遍高于北方。而北方城市之间效益差异亦较大,其中京津冀地区及西北地区的城市雨水处理效益尤低。不同技术设施之间差异表现为:原地入渗设施的雨水处理成本在6~188元/m3之间,显著高于具有汇流功能的设施。对降水较少的北方城市建议采用成本低、效果好的下沉式绿地结合雨水湿地的方式;对雨量大、雨强高的南方城市建议采用生物滞留设施结合调节塘的方式,可增大调蓄能力达到降雨场次控制率的要求,同时能够净化地面径流、增强雨水下渗。

With accelerating urbanization, population growth, and urban expansion, modern urban stormwater management faces new challenges. Based on the scenario analysis method, this study analyzed the costeffectiveness of China＇s urban low impact development（LID） technical facilities. We calculated the benefits of different facilities under 80% and 95% rainfall event control rate scenarios respectively in the 30-year service period. The results show that the cost of construction and maintenance in the northern cities are higher than those in the southern cities. Benefits of stormwater management in the southern cities are generally higher than those in the northern cities. In addition, within the northern cities, benefits of urban stormwater management are lower in Beijing, Tianjin, and northwest regions. For different facilities, the cost of stormwater management for in situ infiltration is between 6 and 188 yuan/m3, significantly higher than the technical facilities with confluence function. Due to their low cost and reasonable effectiveness, combined sunken green area and rainwater wetland are suggested for northern cities with low precipitation. In the southern cities with more rainfall and strong rainfall intensity, it is recommended to use biological retention facilities in combination with regulating ponds.These methods not only can increase the storage capacity to meet the requirements of rainfall control rate but also can increase the rainwater infiltration and help purifying rainwater on the ground.