Mobile bank conditions for laminar microrivers

The present study aims to establish a simple mechanistic model for river bank erosion. Recent experiments demonstrate that small-scale laminar flumes can develop erosion structures similar to those encountered in Nature. From the Saint-Venant Equations, a classical sediment transport law and a simple avalanche model, it is shown that bank failure caused by flow erosion can be represented through simple boundary conditions. These conditions are able to deal with the water level adjustment imposed by a constant water outflow condition. Finally, they are implemented to approach numerically the widening of a laminar river.