As floods are a major and growing source of risk in urban areas, there is a necessity to improve flood risk management frameworks and civil protection through planning interventions that modify surface flow pathways and introduce storage. Despite the complexity of densely urbanised areas, modern flood models can represent urban features and flow characteristics to help researchers, local authorities, and insurance companies to develop and improve efficient flood risk frameworks to achieve resilience in cities. A cost-benefit driven source-receptor flood risk framework is developed in this study to identify (1) locations contributing to surface flooding (sources), (2) buildings and locations at high flood risk (receptors), (3) the cost-benefit nexus between the source and the receptor, and finally (4) ways to mitigate flooding at the receptor by adding Blue-Green Infrastructure (BGI) in critical locations. The analysis is based on five steps to identify the source and the receptor in a study area based on the flood exposure of buildings, damages arising from flooding and available green spaces with the best potential to add sustainable and resilient solutions to reduce flooding. The framework was developed using the detailed hydrodynamic model CityCAT in a case study of the city centre of Newcastle upon Tyne, UK. The novelty of this analysis is that firstly, multiple storm magnitudes (i.e. small and large floods) are used combined with a method to locate the areas and the buildings at flood risk and a prioritized set of best places to add interventions upstream and downstream. Secondly, planning decisions are informed by considering the benefit from reduced damages to properties and the cost to construct resilient BGI options rather than a restricted hydraulic analysis considering only flood depths and storages in isolation from real-world economics.

翻译：洪水是城市区域主要且日益增长的风险源，因此有必要通过规划干预措施来改进洪水风险管理框架和民事保护，这些措施需改变地表径流路径并引入蓄滞设施。尽管高密度城市化区域具有复杂性，现代洪水模型已能表征城市特征与水流特性，帮助研究者、地方当局和保险公司开发并完善高效的城市洪水风险框架以实现城市韧性。本研究构建了成本效益驱动的源-受体洪水风险框架，用于识别：（1）导致地表洪水的源头区域（源），（2）高洪水风险建筑与位置（受体），（3）源与受体之间的成本效益关联，以及（4）通过在关键位置增设蓝绿基础设施（BGI）来减轻受体处洪水的策略。分析基于五个步骤，依据建筑物洪水暴露度、洪水造成的损害以及具有最佳可持续与韧性减排潜力的可用绿地，确定研究区域内的源与受体。该框架利用高精度水动力学模型CityCAT在英国纽卡斯尔市中心案例中开发。本研究的创新点在于：首先，结合多种降雨强度（即小洪水与大洪水）与识别洪灾风险区域及建筑物的方法，制定上游与下游干预措施的最佳优先布置方案；其次，规划决策不仅基于孤立的洪水深度与蓄滞量等水力学分析，更通过考量减少财产损失带来的效益与建设韧性BGI选项的成本，而非脱离现实经济因素。