River width adjustment. II: modeling

Many existing numerical models of river channel morphology are limited in applicability because they neglect time-dependent changes in channel width. In this paper, the status of held-based and numerical modeling approaches for assessing river channel width adjustments is reviewed. This review complements the review of fluvial hydraulics and bank mechanics presented in the companion paper. In addition to describing a field-based approach for assessing channel width adjustments, the quantitative time-dependent models of width adjustment that are currently available are described. Relatively few numerical models of width adjustment have been developed to date, and many processes of width adjustment have never been successfully quantified. Existing models are research tools and are not yet ready to be adopted in widespread engineering practice. An interdisciplinary approach to the analysis and modeling of river width adjustments is presented. The hierarchical approach to analysis of width adjustment is based on field, analytical, and numerical modeling techniques. The principal limitations of existing field-based and numerical modeling approaches are listed. A List of recommendations for further research is provided.