基于历史灾害情景再现的小流域山洪风险研究

Risk of Flash Flood Disaster in Small Basin Based on Historical Scene Representation

山洪灾害威胁着山丘区人民的生命财产安全。随着我国城镇化进程的加快,山区土地类型和环境状况都在发生变化,也影响了山洪灾害风险。以粤西马贵河流域为例,基于HEC-HMS水文模型与Flo-2d水动力模型耦合的数值模拟结果进行了危险性评估,以土地利用类型等级划分表示承灾体易损性,完成了历史灾害再现下流域内三个不同区块2009年和2019年下垫面情景的山洪灾害风险评估,探究不同垫面情景风险差异及其原因。结果表明:流域不同流段,灾害风险水平有明显差异;在经历特大山洪灾害十年后,马贵河流域总体风险水平仍然有增加趋势;城镇化进程中建设用地向山洪危险区扩张,是风险增加的主要原因。

Flash flood disaster threatens the life and property safety of people in mountainous areas.With the acceleration of urbanization in China,land types and environmental conditions in mountainous areas are changing,which also affect the risk of flash flood.Maguihe basin in west of Guangdong province is studied as an example.The hazard assessment is based on the numerical simulation results of HEC-HMS hydrological model coupled with Flo-2d hydrodynamic model,and the vulnerability of disaster-bearing body is indicated by the classification of land use type.Flash flood disaster risk assessment was completed with historical disaster reconstruction for three different blocks in the basin under the scenario of underlying surface of 2009 and 2019,to explore the risk differences and causes in the research area under the two underlying surface scenarios.The results showed that the regional risk level was significantly different in different flow segments.After ten years of flash flood disaster,the overall risk level of the study area still increased.The main reason for the increased risk is the expansion of construction land to flash flood danger areas in the process of urbanization.