There are some differences between the debris flows formed in valley areas and those formed onhilly plateau planes.The formation and characteristics of debris flows in the Zhusang scenic spot in YajiangCounty of Sichuan Proince were studied by field investigation

on-the-spot survey and sieving test.Resultsindicate that:(1)The special climate with intensive sunlight and large difference in temperature plays animportant role in the formation of gully-type debris flows on the hilly plateau planes by making physicalweathering processes intensive

solid deposits loose

slope stability low and supplied materials abundant.(2)Landslide and gully-bed erosion consist of two main material-supplying ways.(3)The dynamic conditions of debris flow are relatively weak.(4)In terms of drainage characteristics

the longitudinal curve takeson a poly-line configuration and the conflux zone and formation zone can be divided obviously.(5)Comparedwith the debris flows in the valley areas

the debris flow deposits on hilly plateau planes are more uniform ingrain size.