水敏感性城市设计(WSUD)作为缓解洪水泛滥(也称为山洪)的可持续方法,引起了越来越多的关注。在气候变化和城市化的影响下,预计频率和强度会增加。然而,WSUD的空间规划不是一件容易的事,不仅由于复杂的城市环境,但事实上,并非集水区的所有位置都对防洪同样有效。在这项研究中,我们开发了一个新的WSUD空间优先级框架,该框架应用全球敏感性分析(GSA)来确定WSUD实施将最有效地缓解洪水的优先子集水区。第一次,可以评估WSUD位置对集水洪水量的复杂影响,水文建模中的GSA被用于WSUD空间规划中的应用。该框架使用空间WSUD规划模型,城市生物物理环境和技术模拟器(UrbanBEATS),生成基于网格的集水区空间表示,和城市排水模型,美国环保局雨水管理模型(SWMM),模拟集水区洪水。在GSA中,所有子集水区的有效不渗透性同时变化,以模仿WSUD实施和未来发展的效果。根据通过GSA计算的对集水区洪水的影响,确定了优先子集水区。该方法已在悉尼的城市化集水区进行了测试,澳大利亚。我们发现高优先级子集水区聚集在主要排水网络的上游和中游,有几个分布在集水区附近。降雨频率,子流域特征,和管网配置被认为是决定不同集水区变化对集水区洪水影响的重要因素。通过比较在四种WSUD空间分布情景下去除悉尼集水区6%的有效不透水面积的效果,验证了该框架在识别有影响的子集水区方面的有效性。我们的结果表明,在高优先级子集水区实施WSUD始终实现了最大的洪水量减少(1%AEP至50%AEP风暴为3.5-31.3%),在大多数设计风暴下,其次是中等优先分集水区(3.1-21.3%)和全集水区实施(2.9-22.1%)。总的来说,我们已经证明,所提出的方法可以通过识别和瞄准最有效的位置来最大化WSUD洪水缓解潜力。
Water Sensitive Urban Design (WSUD) has attracted growing attention as a sustainable approach for mitigating pluvial flooding (also known as flash flooding), which is expected to increase in frequency and intensity under the impacts of climate change and urbanisation. However, spatial planning of WSUD is not an easy task, not only due to the complex urban environment, but also the fact that not all locations in the catchment are equally effective for flood mitigation. In this study, we developed a new WSUD spatial prioritisation framework that applies global sensitivity analysis (GSA) to identify priority subcatchments where WSUD implementation will be most effective for flood mitigation. For the first time, the complex impact of WSUD locations on catchment flood volume can be assessed, and the GSA in hydrological modelling is adopted for applications in WSUD spatial planning. The framework uses a spatial WSUD planning model, the Urban Biophysical Environments and Technologies Simulator (UrbanBEATS), to generate a grid-based spatial representation of catchment, and an urban drainage model, the U.S. EPA Storm Water Management Model (SWMM), to simulate catchment flooding. The effective imperviousness of all subcatchments was varied simultaneously in the GSA to mimic the effect of WSUD implementation and future developments. Priority subcatchments were identified based on their influence on catchment flooding computed through the GSA. The method was tested for an urbanised catchment in Sydney, Australia. We found that high priority subcatchments were clustering in the upstream and midstream of the main drainage network, with a few distributed close to the catchment outlets. Rainfall frequency, subcatchment characteristics, and pipe network configuration were found to be important factors determining the influence of changes in different subcatchments on catchment flooding. The effectiveness of the framework in identifying influential subcatchments was validated by comparing the effect of removing 6% of the Sydney catchment\'s effective impervious area under four WSUD spatial distribution scenarios. Our results showed that WSUD implementation in high priority subcatchments consistently achieved the largest flood volume reduction (3.5-31.3% for 1% AEP to 50% AEP storms), followed by medium priority subcatchments (3.1-21.3%) and catchment-wide implementation (2.9-22.1%) under most design storms. Overall, we have demonstrated that the proposed method can be useful for maximising WSUD flood mitigation potential through identifying and targeting the most effective locations.