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：洪水是城市地区主要且日益增长的风险源，因此有必要通过规划干预措施（如改变地表水流路径和引入储水设施）来完善洪水风险管理框架和民防体系。尽管高密度城市化区域具有复杂性，现代洪水模型能够表征城市特征和水流特性，从而帮助研究人员、地方当局和保险公司开发并优化高效的洪水风险框架，以实现城市韧性。本研究开发了一种基于成本效益驱动的源-受体洪水风险框架，用于识别：(1) 导致地表洪水的区域（源），(2) 面临高洪水风险的建筑和区域（受体），(3) 源与受体之间的成本效益关联，以及最终 (4) 通过在关键位置增设蓝绿基础设施（BGI）来缓解受体洪水的途径。该分析基于五个步骤，在选定研究区域内根据建筑的洪水暴露程度、洪水造成的损失以及具有最佳潜力的可用绿地空间，识别源和受体，以增加可持续且具韧性的解决方案来减少洪水。该框架采用详细水动力模型CityCAT在英国纽卡斯尔市中心案例中开发。本分析的创新点在于：首先，结合多种暴雨强度（即小规模和大规模洪水），运用一种方法定位存在洪水风险的区域和建筑，并确定上下游优先干预的最佳位置集合。其次，规划决策的制定不仅局限于仅考虑洪水深度和储量的水力分析，而是基于减少财产损失带来的效益与建设韧性BGI方案的成本之间的权衡，从而与现实经济因素相结合。