基于GIS的清远市瑶安小流域山洪灾害风险评价

Risk Assessment of Mountain Torrent Disaster at Yaoan Small Watershed in Qingyuan City Based on GIS Technique

为有效地整治瑶安小流域山洪灾害,以降雨、高程、坡度、土壤类型、人口密度和土地利用类型等作为瑶安小流域山洪灾害风险评价指标,基于GIS技术和层次分析法建立山洪灾害风险评价模型,制作山洪灾害危险性、易损性和风险区划图,对该流域山洪灾害进行风险评价。结果表明,瑶安小流域高风险区主要集中在地势较为平缓、人口较多、经济较为发达的下游区域,较高风险区集中在山洪灾害危险性较高、居民点分布相对较多的中上游地区,风险度较低区域主要集中在流域东部地区,评价结果与该流域山洪灾害实际情况较为吻合。

In order to renovate effectively mountain torrent disaster at Yaoan small watershed, taking rainfall, eleva- tion, slope, soil type, density of population and land use types as risk assessment index, the risk assessment model is es- tablish based on the GIS technology and AHP method. The zoning maps of danger, vulnerability and risk of mountain torrent disaster are made, and the risk of the watershed is deeply estimated. The resu[ts show that the high risk area of the basin is mainly concentrated in the downstream area of gentle terrain, the larger population, economy of the devel- oped, the higher risk area is concentrated in the area of the middle and upper watershed in which the mountain torrent dis- aster risk is higher, the settlements distribution is relatively more, the lower risk area is mainly concentrated in the eastern area of the basin. The evaluation result is basically consistent with the actual situation of mountain torrent disaster of the basin.