, and a field soil profile was modelled in a test tank with an open side. The results revealed that the occurrence of the collapse of overhanging layers could be attributed to the development of a scour hole in the open side; the greater the flow rate, the lower
the proportion of on-wall runoff. On-wall runoff played a more important role in the development of scour holes than off-wall runoff. The shape of scour holes formed under different flow conditions was similar. Also, the scour hole is not apparently related