杂谷脑河流域暴雨型泥石流沟地貌特征分析

沟谷的地貌特征是泥石流灾变过程中的一个重要的缓变因子。它决定泥石流形成的动力条件,制约水源条件中的地表径流汇流过程,影响固体物质补给的方式。因此,可以通过研究流域地貌特征来分析泥石流灾害发育特征。以杂谷脑河中游的暴雨型泥石流沟为研究对象,分析了定量描述沟谷发育阶段的流域地貌信息熵,流域面积以及沟床纵比降与泥石流灾害特征之间的关系。结果发现,泥石流沟流域地貌信息熵值处于为0.12～0.20之间时,沟谷属于中高频的泥石流沟,熵值位于区间之外的沟谷则属于低频泥石流沟;沟谷流域面积大于15km2,沟床纵比降小于300‰时,发育稀性泥石流,反之则发育黏性泥石流。

Geomorphic Features of Rainstorm-induced Debris Flow Gullies in Zagunao River Basin

Geomorphic features of a gully is an important slowly varying factor in the processes of debris flow,which determine the driving forces of debris flow,restrict the surface runoff converge among water source conditions and influence the ways of solid material supply.Therefore,debris flow occurrence can be analyzed by the geomorphic features of a drainage basin.By taking a rainstorm-induced debris flow gullies in the middle of Zagunao River basin as the research object,the relationships among geomorphic information entropy in gully development stages,basin area,longitudinal channel bed gradient and debris flow disaster characteristics are analyzed.Geomorphic information entropy of the high frequency debris flow gullies is found to be 0.12~0.20 and the low frequency debris flow gully,0~0.12 and 0.20~0.30,respectively.When gully area is >15 km2 and longitudinal channel bed gradient is <300‰,debris flow is watery,and on the contrary,is viscous.