基于AHP和ArcGIS的罗平县板桥小流域山洪灾害风险评价

Risk Assessment of Mountain Flood Disaster in Banqiao Small Watershed of Luoping County Based on AHP and ArcGIS

摘要: 为进一步明确滇东山区小流域山洪灾害高风险区分布情况，有效防治境内小流域山洪灾害，本文以滇东地区罗平县板桥河典型山区小流域为例，选取年平均降雨量、最大3 h降雨、高程、坡度、土壤类型、植被覆盖度、河网密度、人口密度、土地利用类型、人均GDP、路网密度11个指标，应用层次分析法构建风险评价指标体系，基于ArcGIS对板桥小流域山洪危险性和易损性进行评价，并制作了板桥小流域风险区划图。由风险评价结果可知，罗平县板桥小流域山洪灾害高风险区主要集中在流域西北角的河流下游降水多、地势低、河网密度大、人口及耕地较多的区域，即板桥镇政府及其周边区域，包括板桥居委会、东胜居委会以及牛补歹村委会大部区域，且呈现自东南向西北风险度等级逐渐递增的趋势。该评价结果与流域历史山洪情况较为相符。通过对罗平县典型的板桥小流域进行实证研究，为山区小流域洪水灾害风险区划提供了直接的论证方法。

Abstract: In order to further confirm the distribution of high-risk areas of small water flowing areas in eastern Yunnan mountain and effectively prevent mountain torrents in the areas, this paper takes a typical small water flowing area in Banqiao River in Luoping County of Eastern Yunnan as an example and selects 11 indicators of the annual average rainfall, maximum 3-hour rainfall, elevation, slope, soil type, vegetation coverage, river network density, population density, land use type, per capita GDP, to evaluate the risk and vulnerability of mountain torrents in Banqiao based on ArcGIS and produce the risk distributing map of Banqiao small rivers. The results of risk assessment show that the high-risk areas of mountain torrent disasters in Banqiao small water flowing areas of Luoping County are mainly located in the downstream areas of the river in the northwest corner of the basin, where there are more rainfall, low terrain, high density of river network, more population and arable land. The high-risk areas include Banqiao town government building and nearby areas covering Banqiao neighborhood committee, Dongsheng neighborhood committee and Niubudai village committee and present gradually increasing trend from southeast to northwest. The evaluation results are also in good agreement with the local historical mountain torrents records. The study results in the paper provide a direct verified method for determination of the flooding risk parts of mountainous small water flowing areas.