Regionalization Of Flood Disasters Risk In Beijing GIS

Flash flood occurs in our country frequently. It makes a serious threat to people’s life and property. It is the most important problem in disaster prevention and mitigation currently. According to official statistics, the losses of the country and people due to flash flood disasters accounts for about40%of the total losses by natural disasters in China.The overall characteristics of flash flood in China are influencing widespread, frequently occur, huge harm and significant regional differences.Risk zoning of flash flood is an effective non-engineering measure for flood control and disaster prevention which can change from passive position to active position. As an important component of the flood control and disaster prevention system, risk zoning of flash flood helps Flood Control Department make science decision, avoid disaster effectively, it also helps Water Department insure the flood control standards and plan flood control engineering construction. It can provide technical guidance and serves about flood control and disaster prevention and avoiding-danger for the urban construction, land planning, the production and operation in all industries, people’s living and so on.This paper is based on the analysis of natural environment and human environment background of Beijing Mountains, according to the system theory of natural disaster, selects the evaluations from disaster factors, natural disaster index and body for disaster. This paper considers rainfall, topography, water, arable land and population factors to build the index system of the zoning of Beijing flash. Then selects surface elevation, slope, drainage density, the average monthly rainfall, maximum rainfall in24hours and6hours, geological environment as risk factors, population density, the percentage of arable land, road network as vulnerability factors, and uses AHP method to give weight to each factor, then use GIS spatial analysis technology to obtain the flash flood hazard map of Beijing Mountains and flash flood vulnerability map. Through the overlay analysis of ArcGIS software for the flash flood hazard map of Beijing Mountains and flash flood vulnerability map, and in accordance with the principles of risk zoning, the level of risk in the study area will be divided into low-risk, low-medium risk, medium risk and high-risk four levels, and finally to town as a unit for risk zoning, the n get the zoning map. According to zoning result, the relevant departments in Beijing can be undertaken according to the actual situation of the township the size of the risk level of each township more scientific, more effective and more targeted flood control work, and according to the different towns of the specific local conditions to develop township flood control measures.