基于流域划分的汶川县潜在突发性泥石流危险性评价

Wenchuan Potential Sudden Debris Flow Hazard Assessment based on Watershed Divide

泥石流是我国西南山区常见的一种地质灾害。5·12地震构成了众多隐蔽的不稳定斜坡,在强降雨条件下,这些潜在的不稳定斜坡极易形成突发性泥石流。在流域划分的基础上,基于不同尺度将汶川县划分为不同的流域单元,选取评价因子,建立评价模型,最终实现整个汶川县潜在突发性泥石流危险性评价。结果表明:若按集水阈值20万、30万与40万划分流域单元,则潜在突发性泥石流高危险性及以上单元分别有58、59与30个,占流域单元总数的43.61%、67.05%与57.59%。

Debris flow is one of the serious geologic hazards in southwest of China. '5.12' Wenchuan earthquake constitute a large number of hidden unstable slopes.In heavy rain conditions,these potentially unstable slopes are very easy to form sudden mudslides.For this purpose,on the basis of the watershed division,the Wenchuan County is divided into different watershed unit using different scales,select the evaluation factor,evaluation model,and achieve the potential sudden whole Wenchuan County Debris Flow Hazard Assessment.The assessment results can provide reference and basis for Wenchuan debris flow disaster prevention and mitigation planning.Meanwhile,the results show that if the watershed scale was 200 000,300 000,400 000,the high and above risk of potential sudden debris flow were 58,59,30,accounting for43.61%,67.05%,57.59% percent of the total watershed unit.