Sediment Transport, Part I: Bed Load Transport

TLDR

The study introduces a method to compute bedload transport as the product of saltation height, particle velocity, and bed‑load concentration, and proposes a simple expression for bed‑load concentration based on flow and sediment conditions. The method derives saltation height and velocity by numerically solving solitary‑particle motion equations, calibrating the model with gravel experiments using a free lift coefficient, and then uses the results to compute saltation characteristics and bed‑load concentration across various flow conditions. Verification against about 600 data points shows that roughly 77 % of the predicted bed‑load transport rates fall within a factor of 0.5 to 2 of the observed values.

Abstract

A method is presented which enables the computation of the bedload transport as the product of the saltation height, the particle velocity and the bed‐load concentration. The equations of motions for a solitary particle are solved numerically to determine the saltation height and particle velocity. Experiments with gravel particles (transported as bed load) are selected to calibrate the mathematical model using the lift coefficient as a free parameter. The model is used to compute the saltation heights and lengths for a range of flow conditions. The computational results are used to determine simple relationships for the saltation characteristics. Measured transport rates of the bed load are used to compute the sediment concentration in the bed‐load layer. A simple expression specifying the bed‐load concentration as a function of the flow and sediment conditions is proposed. A verification analysis using about 600 (alternative) data shows that about 77% of the predicted bed load‐transport rates are within 0.5 and 2 times the observed values.