Modeling particle transport distances as a function of slope and surface roughness.

摘要

Significant effort has been put into modeling the evolution of hillslope profiles through time. The models use a continuum approach and are commonly deterministic. Early models assumed a linear relationship between hillslope angle and sediment flux. This relationship produces hillslope profiles that increase in steepness from crest to base. However, hillslopes observed in the field are commonly planar downslope of their convex crests. Recently, non-linear sediment transport equations have been developed that produce hillslope profiles closer to those which are observed in nature, yet the mid-slope sections are not entirely planar. Currently, there is interest in using a non-deterministic approach where transport distances follow probability distributions that depend on hillslope angle. In order to qualitatively and quantitatively characterize this probabilistic relationship, the transport distances of individual particles released into a dry ravel flume with a rough surface were measured as a function of flume angle. Using the inputs of flume angle and surface roughness, the results of the experiments were replicated with a discrete element model in which the motion of the particles was modeled with the momentum equation. The implication of this study is that this method can be used with inputs measured from the field to model the evolution of entire hillslopes.