Quantitative Analysis and Optimization of Flood Disaster Prevention in Nanhai District Under Extreme Weather Scenarios

Abstract

In the context of extreme climate change, the risk of severe rainstorms and flood disasters is continually increasing, causing significant casualties and economic losses. Therefore, it is crucial to implement a series of measures and mechanisms to prevent and mitigate these disasters. This study focuses on the Nanhai District of Foshan City, starting with an analysis of the key disaster-inducing factors for floods. It combines multi-source data such as historical floods, topography, and meteorological hydrology to construct a risk assessment index system. Subsequently, a flood disaster risk assessment model is established using the GBDT algorithm, which determines the risk levels of flood disasters. The study then quantitatively analyzes disaster prevention, disaster response, and recovery measures, by optimizing the threshold ranges of key disaster-inducing factors to determine the risk levels. Finally, by analyzing the changes in risk levels before and after the intervention, the effectiveness of the flood disaster blocking measures is evaluated under different rainstorm scenarios. The results indicate that: (1) In the risk assessment model, the very high risk areas are mainly concentrated in the eastern region; (2) After implementing blocking measures, the key disaster-causing factors that need to have their thresholds optimized are flood depth, submerge duration, population density, and GDP density. (3) The constructed disaster blocking framework demonstrates an effective blocking effect. In the scenarios of 20-year, 50-year, and 100-year rainstorm, the very high-risk areas decreased by 1.01%, 1.68%, and 2.07% respectively. This research provides valuable theoretical reference for enhancing the overall disaster prevention and reduction capacity of the Nanhai District.

Keywords: rainstorm and flooding, Flood disaster prevention, disaster-causing factors, Nanhai district