栾川暴雨泥石流易发性实时动态区划

Real-time dynamic zoning of rainstorm debris flow-prone characteristics in Luanchuan County

河南省栾川县是暴雨型泥石流易发地区,历史记载该县曾数次发生区域性泥石流。2007年及2010年栾川县又暴发了两次大规模泥石流灾害,全县损失惨重。为了给栾川县泥石流防灾减灾提供有效途径,结合野外泥石流调查数据及GIS技术探讨,建立了栾川暴雨型泥石流易发性实时动态区划模型。该模型系由物源积聚、径流产能及土体强度弱化等三大条件11个因子构成,通过计算易发指数和净易发指数二值,实时判别栾川县泥石流高易发区域并进行预警;因子权重通过三标度层次分析法进行赋值;因子本身划分成不同级别并按1到0进行量化。同时,结合2010年"7·24"暴雨型泥石流灾害点对模型进行了验证,结论表明,模型同时适用于坡面型泥石流和沟谷型泥石流,具有实用价值。最后基于上述模型,认为易发指数>0.216且净易发指数>0.05可作为栾川县暴雨型泥石流暴发预警警戒值。

Luanchuan County is prone to rainstorm debris flow. Several regional debris flows had occurred as historical data recorded. In 2007 and 2010, two large scale debris flow hazards occurred again and the county suffered great losses. In order to provide an effective way for Luanchuan County debris disaster prevention and reduction, a real-time dynamic zoning model of debris flow-prone characteristics was established and discussed based on field investigation data and GIS. The model consists of three conditions of source accumulating, runoff productivity and soil strength reduction, and includes 11 factors. By calculating the occurrence prone index values and net occurrence prone index values, the model can distinguish debris flow-prone area and thus issue early warnings. Weights of the factors＇ were assigned using the TAHP method, and the factors are divided into different levels measuring by values from 0 to 1. The model was validated by the Luanchuan ＂7.24＂ rainstorm debris disaster points. Results show that the model is suitable both for slope type and gully type debris and is practical. Finally, based on the above model, debris warning values for Luanchuan rainstorm are given, i. e., the occurrence-prone index value is greater than 0.216 and the net occurrence-prone index value is greater than 0.05.