Abstract: Climate change and rapid urbanization in recent years have resulted in a significant increase in urban flood risk, posing a considerable threat to sustainable and healthy development of the cities. Refined modelling of urban flood and waterlogging is often crucial to efficient flood management and requires better reliability and fineness of the flood model outputs. The sponge city pilot area of Jinan City was selected as a study case, where the special terrain and landform is conducive to urban flooding. Data of the refined urban land surface were collected using UAV-based oblique photography; and using these data, we have developed a hydro-hydrodynamic coupling model for interaction of various processes and applied it to analysis of the effect of terrain resolution on flood modeling. The results show that fine data resolution of the urban terrains is vital to accurate flood modeling, and using Digital Surface Model (DSM) or neglecting the walls in modeling will lead to overestimation or underestimation of the flood, which is really adverse. This study provides reliable, fine flood data to refined urban flood risk management in Jinan City.

Key words: urban flood simulation, UAV, hydro-hydrodynamic modeling, terrain resolution, Jinan City