The combination of vertical bed change in the classical HEC-RAS mobile bed computations and the bank failure algorithms can model the interaction of model incision and bank failure. As a channel incises the potential failure plane through the new exposed toe, the bank steepens and the FS drops. Therefore, incision can induce bank failure (or conversely deposition can stabilize banks). However, there is a third that neither the HEC-RAS sediment model nor the bank failure model covered above capture, which is important in modeling bank erosion and loads - toe scour.

Toe scour is a fluvial, hydraulic process driven by the flow (versus bank failure which is primarily a gravity driven geotechnical process). The classical mobile bed algorithms in HEC-RAS only compute vertical movement of the bed, but hydraulic forces can undermine the toe of a bank, which can reduce the length of the failure plane (and the frictional resistance) and decrease the factor of safety of the critical failure plane faster than incision.