Abstract: Waterlogging disasters have occurred frequently in Ordos in recent years, but few previous studies conducted a high-resolution simulation of the waterlogging process in its urban area. Usually, traditional hydrodynamic models struggle to meet such real-time forecasting needs due to large computational demands. This study develops a numerical simulation approach for urban waterlogging that balances simulation accuracy and computational efficiency, aimed at a practical tool efficient and reliable for urban flood prevention and disaster mitigation. We construct a high-performance hydrodynamic model of urban waterlogging in the study area－the central urban area of Kangbashi District, Ordos City－and generate a meter level elevation mesh through multi-source data fusion; Then we simulate and examine its waterlogging process under the design rainstorms of different return periods. The parallel computing performance of this model is tested on the national supercomputing platform. Results show that it achieves waterlogging simulations with a satisfactory accuracy, identifies the waterlogging prone points, and reconstructs the surface runoff process. Its thousand-CPU core calculations are a thousand times faster than serial calculation, so that simulating a waterlogging process of several hours long takes just a few minutes of wall clock time. The findings would help implement the real-time warning and emergency management of urban waterlogging and promote parallel computing of large CPU-cost hydrodynamic models.

Key words: waterlogging simulation, hydrodynamic model, high-performance computing, parallel performance, Ordos