Debris Flow Hazard Assessment for the Bailongjiang River, Southern Gansu
基于GIS和信息量法的甘肃南部白龙江流域泥石流灾害危险性评价

The Information Method is widely used in debris flow hazard assessment. In southern Gansu, the massive earthquake in Wenchuan provided a large amount of loose material and accelerated the occurrence of landsides and debris flow disasters. It is now necessary to investigate and analyze the factors that influence the debris flow in order to conduct a hazard assessment and prevention methods. Here, elevation, slope, lithology, land use, the density of landsides, cumulative distance from fault interface and normalized NDVI (normalized difference vegetation index) were selected for the Bailongjiang River as evaluation indexes for topography, geomorphology, geology and environmental conditions. We first classified influencing factors and then based on GIS and information methods generated evaluation factors information layers. The seven information layers were generated with Arcgis based on information values models and combined to arrive at a comprehensive information layer for debris flow hazards, and ultimately a debris flow hazard zoning map. The study area was divided into an extremely highly danger zone, high danger zone, moderate danger zone, mild danger zone and very mild danger zone. The results indicate that above moderate danger zone accounts for 88.9% of the total debris flow area;the moderate, high and extremely highly dangerous areas account for 29.48%, 34.33% and 25.10%, respectively. Our results show that information methods and GIS technology can be applied to debris flow disaster hazard assessment with higher accuracy and can contribute to disaster hazard prevention.