The Study on Assessment of Mountain Torrent Susceptibility and its Factors in Dashagou Basin

• 1、School of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China

Abstract：In recent years, extreme heavy rains have often occurred in the flood season on the Loess Plateau, and mountain torrent caused by heavy rainfall conditions often cause severe urban flooding and seriously threaten local life and property safety. Therefore, it is particularly important to carry out related mountain torrent susceptibility research. This paper takes the Dashagou Basin of Lanzhou City as the research object, based on the DEM with a resolution of 20m, based on the Flow-R mountain torrent susceptibility simulation software to quantitatively calculate the probability of mountain torrent susceptibility in the study area, and to carry out zoning of susceptibility. Throughout the study area, there were 4.05% of high-prone areas, 6.24% of medium-prone areas, and 6.04% of low-prone areas. Finally, through analysis of the five major factors of elevation, slope, plane curvature, lithology, and buildings in the susceptible area, It is found that the near-flat loose accumulation channel area with elevation between 1700~1800m and plane curvature between -1~1 with slope<10° is the most heavily affected by mountain torrent. In addition to the original topographical conditions such as slope and plane curvature, the destruction of topographical landforms and vegetation coverage by human engineering activities in the study area is an important factor causing high incidence of mountain torrent. The results show that the mountain torrent susceptible areas calculated by the Flow-R model can be used as an important basis for formulating relevant flood control plans.

Keywords： Geological Resources and Geological Engineering Mountain Torrent Assessment of Susceptibility Flow-R Model Inducing Factors