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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #103638
Title: RIVER WIDTH ADJUSTMENT. II: MODELING

Author
item DARBY, STEPHEN - UNIV SOUTHAMPTON, UK
item THORNE, COLIN - UNIV NOTTINGHAM, UK
item Alonso, Carlos
item BORAH, DEVA - IL STATE WATER SURVEY
item DIPLAS, PANO - VA POLYTH UNIVERSITY
item JULIEN, PIERRE - CO STATE UNIVERSITY
item KNIGHT, DONALD - UNIV BIRMINGHAM, UK
item PIZZUTO, JIM - UNIV DELAWARE
item QUICK, MICHAEL - UNIV BRITISH COLUMBIA
item Simon, Andrew

Submitted to: American Society of Civil Engineers Journal of Hydraulic Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Erosion of unstable stream channels is a principle means of land loss in agricultural watersheds. Sediment from eroding streambanks contributes at least 75% of the material emanating from unstable alluvial channels and poses a significant threat to flood plain resources and agricultural activities through land loss, long-term availability of water resources through reservoir sedimentation, and to downstream habitat and water quality. Stream bank erosion is usually associated with channel deepening and stream meandering. This paper presents an indepth review conducted by an ASCE Task Committee established to evaluate the status of numerical modeling approaches for assessing stream channel deepening and width adjustments. Reliable models are needed to predict the conditions and timing of bank failure because it provides a much more accurate and precise means of analyzing bank stability and stable-bank conditions. The principal limitations of existing modeling approaches are listed, and a list of recommendations for further research is provided. The insight provided by this state-of-art-review will benefit future efforts to enhance bank erosion models based on improved deterministic definitions of process-form relations.

Technical Abstract: 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 field-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.