极端暴雨下绿-灰-蓝基础设施防洪排涝效果评估——以东沙湖流域为例

Assessment of Flood Control Effectiveness of Green-Grey-Blue Infrastructure During Extreme Rainstorms:A Case Study of East-sha Lake Watershed

针对当前城市洪涝研究主要集中在单一的绿色、灰色基础设施或绿-灰色基础设施的不足,基于水文水动力耦合模型对武汉市东沙湖流域进行建模,采用武汉市暴雨经验式并移植郑州“7·20”暴雨生成重现期1~1000a的极端暴雨情景,分析极端暴雨下绿-灰-蓝色基础设施的雨洪控制能力.研究结果表明:绿色基础设施主要应对5a一遇以内的降雨,且有一定的削峰和峰值延缓效果;灰色基础设施排水能力的提高有助于城市应对极端暴雨,且雨强越大其发挥效果越明显,但存在增大峰值和提前峰现时刻的负面作用;蓝色基础设施具有极大的雨洪调蓄潜力,可为应对极端暴雨提供保障,但需考虑其综合效益并制定多级水位调控方案;绿-灰-蓝色基础设施应综合起来优化评估,蓝色基础设施的顶托效应反映了其水力联系和耦合关系.以期该研究为城市内涝灾害治理和海绵城市建设规划提供科学依据.

To address the limitations of urban flooding studies,which mainly focus on a single green or grey infrastructure or green-grey infrastructure,we modeled the East-sha lake watershed in Wuhan based on a coupled hydrological-hydrodynamic model.We generated extreme rainfall scenarios with return periods of 1~1000 years by using the Wuhan rainstorm formula and transplanting the Zhengzhou“7·20”rainstorm event.We analyzed the stormwater control capacity of green-grey-blue infrastructure under extreme rainstorms.The results show that the green infrastructure is efficient for rainfall of 1~5 years,and provides peak shaving and peak delaying effects.The optimization of grey infrastructure helps the city to cope with extreme rainstorms,and its effect is more obvious the higher the rainfall intensity,but it has the negative effect of increasing the peak value and advancing the peak time.Blue infrastructure has great potential for stormwater storage and can provide protection against extreme rainstorms,but its comprehensive benefits need to be considered in the development of multi-level water level control plan.It is necessary to integrate the green-grey-blue infrastructure to optimize the assessment,which is because the backwater effect reflects their hydraulic connection and coupling relationship.This study can provide scientific basis for urban flood disaster management and sponge city construction planning.