基于沟道形态学变迁理论的泥石流形成影响研究——以纸坊沟流域为例

Study on Influence of Mudflow Formation Based on Channel Morphology Change Theory:A Case Study of Zhifanggou Watershed

地表形态是泥石流物源启动和运动的力学基础,流域内的地形地貌特征对泥石流的发生具有重要意义.该文基于ArcGIS的水文分析法,采用2009年和2015年分辨率30×30 m的纸坊沟ASTER GDEM数据,结合野外勘察,从沟道形态变化的方向研究沟道形态变迁对泥石流形成的影响.从2009年至2015年,纸坊沟流域泥石流流域面积减小0.1 km^2 ,高差减小26 m,而平均坡度增大1.43°,平均纵坡比从 38.2‰增大至39.2‰.结果表明,泥石流的爆发和远程运移受到流域形态、沟道形态和坡面形态的共同作用和影响.目前,纸坊沟处于较为稳定的发育时期,大型泥石流的暴发概率较低.

The surface morphology is the source and mechanics basis of the initiation and movement of debris flow source. The topography and geomorphology in the drainage basin is of great significance to the occurrence of debris flow. Based on the hydro-logical analysis method of ArcGIS, this study uses the ASTER GDEM data of 30×30 m resolution in 2009 and 2015, combined with the field survey to study the influence of channel shape change on the formation of debris flow. From 2009 to 2015, the area of the debris flow basin in the Zhifanggou ditch watershed decreased by 0.1 km ^2 , the elevation gap decreased by 26 m, the average slope increased by 1.43°, and the average longitudinal slope increased from 38.2‰ to 39.2‰. The results show that the outbreak and long-distance migration of debris flow are affected by the combination of watershed morphology, channel morphology and slope morphology. At present, the Zhifanggou is in a relatively stable development period, and the probability of large-scale debris flow is low.