In the context of ongoing climate change and extreme rainfall events, urban flooding has become a global challenge. The layout of urban buildings is recognized as a crucial factor influencing flooding. The ability of a city to respond promptly and recover quickly from floods is referred as ’urban flood resilience’. To deepen our understanding of this issue, urban flooding simulation and resilience assessment have emerged as key methods for studying its impacts. This study establishes a hydrodynamic model of urban flooding under extreme rainfall conditions to investigate the runoff characteristics influenced by building layouts. It also explores the mechanisms of water flow resistance in complex terrains. Within a resilience assessment framework, incorporating real-time simulation data and indices characterizing complex terrain, the study employs factor analysis to optimize the framework. It derives a formula for calculating flooding resilience and conducts resilience assessments in the study area. The research reveals that flooded areas predominantly occur in regions with irregular building layouts and high building densities. The impact of extreme rainfall is magnified in areas with irregular buildings. As the irregularity coefficient deviates further from 1, the water resistance effect of buildings becomes more pronounced, with maximum ponding depth increases reaching up to 20 %. An increase in slope results in a 10 % to 30 % rise in maximum ponding depth but reduces the overall flooded area. Maps depicting urban flooding resilience and severity present varying results, offering proactive planning recommendations for urban flooding prevention and control.

中文翻译：

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极端降雨事件下复杂地形对城市抗洪能力的影响


在持续的气候变化和极端降雨事件的背景下，城市洪涝已成为一项全球性挑战。城市建筑的布局被认为是影响洪水的关键因素。城市迅速响应并从洪水中快速恢复的能力被称为“城市防洪能力”。为了加深我们对这个问题的理解，城市洪水模拟和韧性评估已成为研究其影响的关键方法。本研究建立了极端降雨条件下城市洪涝的水动力学模型，以研究受建筑物布局影响的径流特征。它还探讨了复杂地形中水流阻力的机制。在弹性评估框架内，结合实时模拟数据和表征复杂地形的指数，该研究采用因子分析来优化框架。它推导出了用于计算洪水弹性的公式，并在研究区域中进行了弹性评估。研究表明，洪水泛滥区域主要发生在建筑布局不规则和建筑密度高的地区。极端降雨的影响在建筑物不规则的区域被放大。随着不规则系数进一步偏离 1，建筑物的防水效果变得更加明显，最大积水深度增加高达 20 %。坡度的增加会导致最大积水深度增加 10 % 到 30%，但会减少总淹没面积。描绘城市洪水弹性和严重程度的地图呈现不同的结果，为城市洪水预防和控制提供了主动规划建议。