Simulating urban flooding/waterlogging by cellular automata technique: case of downtown Jinan

Dual influences of global climate change and human activities has led to increasingly prominent urban flooding/waterlogging problems．Jinan is more vulnerable to urban flooding/waterlogging due to high terrain in the south and low terrain in the north．A meta-automata CAflood model was constructed in this work to analyze data from six historical rainstorm processes, to simulate flooding under six different return periods．The average error between measured and simulated values was found to be 0.044 m, indicating very good model performance．With increased return period, area of low risk with maximum submerged depth h of ≤ 0.5 m was found to account for a significant proportion of 70%．Area of other affected states was found to increase, and growth trend was fast at first and then became slower．Moderately affected area with 1 m < h ≤ 2 m showed the highest growth rate, increasing from 0.97 km² at the 1-year return period to 6.15 km² at the 100-year return period, an increase of 5.3 times．Flood risk zoning based on inundation depth provided some reference for urban disaster prevention and mitigation．Significant difference between heavy disaster area in the zoning map and historical flood disaster location was found．If only flood simulation is considered in flood risk assessment, without considering social factors, the gained results would have limitations．