Bridging urban and catchment scales in urban pluvial flooding: a multi-resolution simulation tool

Abstract Urban pluvial flooding is a critical challenge as its consequences are worsened by climate change, urbanization, and inadequate infrastructure. Traditional assessment methods often fail to predict detailed surface runoff in complex urban areas. These methods either rely on general hydrological estimations, which lack high precision, or conduct detailed hydrodynamic analyses that focus on the urban area, neglecting runoff contributions from the entire catchment. This research introduces a new methodology and system, designed to support flood management in urban areas by generating high-resolution flood maps through the integration of GIS analysis and satellite sensing–derived datasets. The system is especially useful in data-sparse environments integrating accuracy, computational efficiency, and dynamic modeling through a multi-resolution single simulation approach. The main objective is to develop a model that bridges the gap between hydrological flood assessment tools for hydrological basins and hydrodynamic urban flood simulation systems in densely built environments. The model is assessed at the urban area of Mandra Attiki, Greece, considering the whole catchment runoff. Proposed system produced high-resolution (2 × 2 m) flood depth maps by simulating the historic November 2017 Mandra flood event, achieving approximately the real flood with 80% accuracy, 20% overestimation, and 17% underestimation. Testing results indicate the system capability to simulate floods in multi-resolution scenarios with complex geomorphological and hydrological conditions in a joint simulation process.