Decision Supporting System Of Debris Flow Mitigation For Mountain Towns

Along with the economy developing in mountains area, the scales of mountain towns extend quickly, the population increase rapidly, problems of debris flow stand out increasingly, and the conceivable economic loss and personnel casualties is becoming more and more. Debris flow mitigation has become one of the important parts of disasters mitigation in mountain towns. Setting up debris flow control works is the important measure for debris flow disasters mitigation. However, the works can't resist the debris flow which is over the designing standard of the works. So that it's another important measure for debris flow disasters mitigation to set up a decision supporting system of debris flow disasters mitigation for mountain towns, especially for extraordinary debris flow disasters mitigation.The decision supporting system of debris flow disasters mitigation for mountain towns is a compositive system which includes debris flow monitoring, prediction, forecast, warning, risk zoning, assessment of the situation of a disaster and counterplan for a disaster. It's a new task in debris flow disasters mitigation. Based on the former research on debris flow monitoring, prediction, forecast, warning, assessment of the situation of a disaster and counterplan for a disaster, debris flow forecast, risk zoning, counterplan for a disaster and integration of the system were researched emphatically. The compositive system which supplies the basis and methods of debris flow disaster mitigation for mountain towns was integrate with the technology of data acquisition, data routing, data receiving, computer and GIS. As a case study, Dongchuan, one of prefecture of Kunming, which is harmed and threatened by debris flow more serious, was selected to be researched. And the decision supporting system of debris flow disasters mitigation was set up to illustrate the application of the system.The originality innovations of this paper are as following:1. Because the debris flow forecast mode based on debns flow formation mechanism is being on theory exploring, the debris flow forecast mode based on rainfall statistics is the main method, although the accuracy of this mode is lower. So that how to improve the accuracy and decrease the losses for the lower accuracy is the focal point of the research at present. Considered the different losses from the fail report and misdecaration, the method of debris flow forecast under different losses is set up. This method makes the general average loss of the losses for fail report and misdeclaration to be minimum, and make up for the lower degree of accuracy of debris flow forecast in a certain extent.2. The debris flow movement on the alluvial fan is simulated with the technology of numerical simulation and GIS. A new method of debris flow risk zoning is made out.3. Considering the movements of debris flow on the alluvial fan and in the channel are different, different movement models are used to simulate debris flow movement on the alluvial fan and in the channel. This method of debris flow simulation can not only display debris flow movement course and make debris flow risk zoning, but also can check the debris flow channel.4. A momentum model of debris flow risk zoning is set up according to the distribution of debris flow velocity and depth from the numerical simulation. This model's index of zoning is the distribution of maximum debris flow momentum, so the result of the zoning reflects the maximal force of destruction. On the other hand, this model based on the numerical simulation can supply the extent of debris flow inunation and risk zoning under different debris flow scales and frequencies for the counterplan of debris flow mitigation.5. The concept of debris flow counterplan is taken out for the first time, and the content and principle of the counterplan are made out according to the characteristics of debris flow disasters in mountain towns. A complete method of setting up debris flow counterplan is made out with the basic database of the town as the basement, the e...