ABSTRACT
The presence of underlying bedrock strata covered by erodible sediment layers of finite depth is ubiquitous in rivers and estuaries. Recently, the development of models based on the non-capacity sediment transport assumption has offered a new background to deal with these complex partially non-movable bed configurations. Bedload non-capacity models consider that the actual solid transport discharge can be different from the equilibrium value and is governed by the temporal evolution of the flow. The treatment of finite-depth erodible layers in numerical bedload models based on the capacity approach has usually been made using numerical fixes, which correct the unphysical results obtained in some cases. Nevertheless, this common natural bed configuration has not been previously considered in the development of numerical models. In this work, a 2D finite volume model for bedload transport based on non-capacity approach and dealing with finite-depth erodible layers is proposed. New expressions for the actual bedload transport rate and the net exchange flux through the static-moving bed layers interface are used to develop a 2D x-split numerical scheme which solves the shallow water and non-capacity bedload transport system of equations.
