北京市房山区县域山洪灾害风险评价研究

Risk Assessment of Mountain Torrent Disaster Based on County Territories of Fangshan District in Beijing

评估县域山洪灾害风险对小流域山洪风险预警及分区管控具有重要意义。为此,结合山洪灾害的发生条件、承灾体受损能力及抗灾能力,构建了山洪灾害风险评价指标体系,并以北京市房山区作为典型案例计算山洪灾害风险指数,分析了其在栅格、乡镇、流域分区上的空间分布特性。结果表明,山洪灾害风险评价体系具较高精度;随降雨重现期增加,研究区山洪风险指数增大,灾害风险由东向西扩散;在不同降雨重现期条件下,城乡工矿居民用地均为受灾影响面积最大的土地类型;乡镇区划有利于落实防灾减灾措施,而流域分区可结合山洪灾害发生机制进行防治。

Mountain flood disaster risk assessment at county level is of great significance to mountain flood risk warning and zoning control in small watershed. Combined with the occurrence conditions of mountain flood disaster, the damage capacity of the disaster bearing body and the disaster resistance capacity, the mountain flood disaster risk evaluation index system was established. Taking Fangshan District of Beijing as a typical case, mountain flood risk index was calculated, and its distribution characteristics in grid, township and watershed were analyzed. The results show that the mountain flood disaster risk assessment system has high precision. With the increase of rainfall return period, mountain flood risk index increased and disaster risk spread from east to west. Under different rainfall return periods, industrial and mining residential land was the most affected land type. Township zoning is beneficial to implement disaster prevention and mitigation measures, while watershed zoning can be combined with mountain flood disaster prevention mechanism.