An experimental study of sediment transport in channel confluences

Confluences are common features of natural and man-made channel systems where convergence of joining flows creates a complex flow and sediment transport pattern producing strong flow circulations and rapid changing in bed morphology. By the means of laboratory experiments on several mobile-bed channel confluences, this study (1) investigates and formulates the (not well-understood) flow and geometrical conditions leading to the incipient motion of sediments in channel confluences, and (2) characterizes the effect of flow and geometrical conditions on the main morphological features (e.g. scouring and deposition areas) in confluences. Of prime importance factors that are considered in this study are the flow Froude number, angle of confluence, discharge and width ratios and the bed martial properties. This experimental study provides an insight for better understanding mechanisms involved in sediment transport and bed morphology in channel confluences and also quantifies the influence of various flow and geometrical factors on sediment transport, which are great importance in river engineering designs and fluvial studies.