APPLICATION OF GAST-SWMM COUPLED NUMERICAL MODEL IN LARGE-SCALE URBAN INUNDATION RISK ASSESSMENT
It is very important to carry out the risk assessment of rainstorm-induced inundation in urban areas for inundation regulation and urban security development.This study took the 310 km2 main urban area of Yinchuan as an example,to establish an efficient and high-resolution coupled GAST-SWMM model of urban surface inundation and drainage process of underground pipe network based on GPU acceleration technology.The model was verified by the measured information of inundation points.The inundation location and risk level before and after the planning of the study area were simulated respectively under the condition of 24-hour rainstorms with a return period of 20 years and 30 years.The inundation reduction was analyzed and the inundation risk map was drawn.The results showed that compared with the measured values,the simulation error of the model was less than 6%,and the simulation accuracy was higher.After planning,compared with the situation before planning,the average value of the peak water area reduction rate and peak water depth reduction rate reached 41.6%and 45.03%,respectively,and the average value of the peak water depth reduction rate reached 51.74%and 56.05%,respectively,and the high-risk water points were all reduced to medium risk and low risk.The coupled numerical model has a good application effect in the large-scale urban rainstorm-induced inundation risk assessment,and the research results have important reference value for the prevention and elimination of rainstorm-prone inundation points in Yinchuan.