Risk Appraisal Of Landslide Adjacent To The Dam Site Of Yansangshu Hydro-power Station Base On GIS

As clean and cheap resource, water resource attracts worldwide concern anduse.China is rich in water resource which ranks first in the world.Most of the waterresource distribute in the Southwest of our county. The Southwest locates on thetransition zone between the first step and the second step of our county’s terrainladder, where tectonic movement developed, terrain undulate serious, water systerdeveloped, weathering and erosion intensed, and the rainfall is abundant. Thence,there were so many disasters such as landslide happened frequently in this region,which not only had threaten the hydropower reservoir’s construction and operation,but also had brought serious losses to people’s lives and property. Therefore riskassessment and research on hydropower reservoir for supplying reliable basis fordisaster prevention and reduction to ensure the reservior’s construction and operationsmooth and safe and ensure the safety of people’s lives and property of the reserviorwhich was of great significance.This paper took Yansangshu reserior region as study region, based on GIStechnology and remote sensing images and konkret field survey, looked into thelandslide’s spatial distribute characteristics and genetic mechanism of reservior. Onthess bases used the methods such as AHP The information methodVulnerability composite index and so on to assess the reservior’s landslide risk. Themain research contents and the productions were listed as follows:1. Combined the landslide disaster dates collected by konkret field survey withthe remote sensing images, the development types, scales, grain composition, andgenetic mechanism of the study region were analyzed based on3S technologies,which lay the foundation for landslide hazard assesment of the study area.2. Based on the predecessors’ research results, this paper summarized and analyzed the evaluation models, evaluation units and the establishment of the indexsystem respectively. Then selected slope, aspect, topographic relief, slope structure,lithology, geological structure and river erosion as dominant factors,and selectedrainfall and human activity as induced factors to establish landslide hazard assessmentindex system. Choosed grid unit as evaluation unit to extract the information of eachindex, and discussed the advantage intervals of each factor based on GIS technology.Then combined AHP with the information method to assess the landslide hazard ofthe study region. Finally, used the landslide datas and the method of preditionaccuracy analysis to validate the assessment results.3. The paper summarized and anlyzed the factors affected the landslidevulnerability, and then choosed population density, road density, building density,density of arable land, forest density, GDP and distance from the dam site as sevenevaluation factors to establish the landslide disaster vulnerability assessment indexsystem of the study region. Finally, used the methods of analytic hierarchy processand vulnerability composite index to assess the landslide disaster vulnerability ofthe study region.4. The different definitions of risk defined by different researchers weresummarized and analyzed firstly. Then used the common risk assessment formula asassessment model and the method of risk rating matrix as classification criteria toassess the landslide disaster risk based on the results datas of hazard and vulnerabilityof the study region. The results showed that: the extreme high risk area and high riskarea of the study region were accounted for40.74%.