Sediment transport modeling with HEC-RAS was already complex and highly parameterized before bank failure. Bank failure makes it more complex. Complex models that account for more processes explicitly make careful, strategic, sequential modeling practice more important.
Model processes from simple to complex. Add complexity one step at a time. A stepwise modeling process, that adds complexity incrementally, carefully calibrating and evaluating results of each modeling step, will produce more accurate models and sane modelers.
Create an HEC-RAS/BSTEM model in the following incremental steps, carefully completing, evaluating, and calibrating each step before adding the complexity of the next step.
Calibrate Hydraulics: Create the geometry and calibrate model hydraulics in the steady flow module over the range of expected flows.
Model/Calibrate Sediment Transport: Isolate the sediment transport mechanics by carefully modeling bed sediment without bank processes first. Build a robust (Thomas and Chang, 2012) calibrated model, or at least, evaluate results to understand the sensitive parameters.
Model/Calibrate Bank Erosion and Bank Failure: By setting the cross sections as Pass Through Nodes (under the Options menu in the Sediment Data Editor), users can isolate bank processes and refine bank methods and parameters without the complexity bed process feedbacks.
Integrate Bank Erosion and Failure plus Mobile Bed Sediment Transport Model: After the hydraulics are calibrated and the bed and bank sediment models have been refined independently, then combine all the components, and calibrate the coupled model to bed and bank change.