Predicting Sediment Transport Dynamics in Ephemeral Channels: A Review of Literature

PURPOSE: The goal of this Coastal and Hydraulics Engineering Technical Note (CHETN) is to evaluate state-of-the-art research efforts concerning predicting sediment transport in desert ephemeral channels. The present day methods used to predict sediment transport were primarily formulated for application to perennial flow channels. Additionally, in the development of sediment transport relationships it is assumed that the sediment and water mixture is Newtonian, i.e., a linear relationship exists between the shear stress and the shear rate. Hyperconcentrated sediment flows containing fractions of fine, cohesive sediments may be non-Newtonian in nature. These flows are characterized by a nonlinear relationship between shear rate and shear stress with mixture viscosity a function of shear rate. The transport capacity of a hyperconcentrated non-Newtonian mixture can be much higher than a Newtonian mixture, as well as the capacity of the mixture to transport coarse sediments such as gravels and cobbles. Therefore, the sediment transport processes of erosion, entrainment, transport, and deposition may be quite different for arid region ephemeral channels.