甘肃省陇南市白龙江流域泥石流灾害事件与降水特征的关系

Relationship between debris flow activities and precipitation characteristics in Bailong River Basin of Longnan Region,Gansu Province

甘肃省陇南市白龙江流域泥石流灾害事件高发区与暴雨中心、高发期与暴雨集中期均有很好的对应关系.短时间强降水是激发该区域泥石流的主要降水类型,10 min雨强可以作为该区域泥石流预报因子,灾害事件当次降水量和10 min雨强的函数关系可以用于估算研究区不同区域泥石流临界降水量.沟谷沿岸中、低植被覆盖下的砂岩、粉砂岩、泥岩、千枚岩等软弱岩层区,在强降水条件下较短时间内就会发生泥石流灾害,应在该区域加大防灾减灾力度.

It was showed that a high occurrence area of debris flow events was consistent with a rainstorm center, and the activities of events also changed monthly with the variations in precipitation in the Bailong River Basin of Longnan Region, Gansu Province. Concentrated rainfall in a short time was the main rainfall pattern which triggered debris flows in the study area, and precipitation in 10 minutes could be considered as a factor for regional debris flows prediction, which can be used to estimate the critical precipitation of debris flows. A region with a dense population and sandstone/siltstone/phyllite/loess, etc, which are of weak and fragile lithology, is much more prone to debris flows. Effective measures should be taken for disaster reduction in this region.