The Sensitivity Analysis of Parameters in the 1D–2D Coupled Model for Urban Flooding

The ongoing changes in climate and the rapid pace of urbanization are contributing to an alarming increase in the prevalence of urban flooding, which is having a profound impact on the quality of life for residents and the smooth functioning of urban areas. The 1D–2D coupled model is an effective tool for simulating the process of urban flooding, thereby providing a scientific basis for urban planning, flood prevention, and mitigation strategies. The values of numerous parameters within the model not only influence the computational efficiency but also influence the precision of the simulation outcomes. It is of particular significance to ascertain the sensitivity of model parameters. In this study, a 1D–2D coupled model of urban flooding was constructed, and a parameter sensitivity analysis was conducted using the modified Morris method and the Sobol method in two ways, with the amount of waterlogging as the target. The findings indicate that the minimum infiltration rate is the most sensitive parameter in the local sensitivity analysis, whereas the Manning coefficient of the permeable surface area is the most sensitive in the global sensitivity analysis. The research outcomes can facilitate the optimization of the model parameters and enhance the precision and dependability of the model predictions, thereby providing more accurate data support for urban flooding early warning and emergency response.