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United States Department of Agriculture

Agricultural Research Service

Title: Modelling Width Adjustment in Straight Alluvial Channels

Author
item Darby, Stephen

Submitted to: Hydrological Processes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 11, 1996
Publication Date: N/A

Interpretive Summary: Many existing numerical alluvial channel models are limited because they are unable to account for adjustments of channel width through time. In this paper, the basis for modeling width adjustment in straight river channels is reviewed. Features and capabilities of selected models are discussed in terms of advances made in representing the physical processes and mechanisms involved in width adjustment, and in terms of approaches used to characterize initial and boundary conditions accurately. Each aspect of modeling width adjustment is discussed separately. These aspects include description of the flow field, modeling sediment transport, modeling bank erosion and mass failure, and simulating changes through time of bed material particle size. Validation and verification studies of existing width adjustment models are also considered. Existing models have for the most part not yet been subjected to rigorous evaluation of their numerical robustness, accuracy in replicating analytical solutions, accuracy in replicating laboratory data, or their ability to simulate field situations. In part, these limitations reflect the lack of available detailed laboratory and field data sets required to evaluate complex models. The paper concludes with a critical examination of available models and recommendations for future research. 

Technical Abstract: Many existing numerical alluvial channel models are limited because they are unable to account for adjustments of channel width through time. In this paper, the basis for modelling width adjustment in straight river channels is reviewed. Features and capabilities of selected models are discussed in terms of advances made in representing the physical processes and mechanisms involved in width adjustment, and in terms of approaches used to characterize initial and boundary conditions accurately. Validation and verification studies of existing width adjustment models are also considered. Existing models have for the most part not yet been subjected to rigorous evaluation of their numerical robustness, accuracy in replicating analytical solutions, accuracy in replicating laboratory data, or their ability to simulate field situations. In part, these limitations reflect the lack of available detailed laboratory and field data sets required to evaluate complex models. The potential of width adjustment models for use as tools for investigation of river channel dynamics is briefly described using two examples. 

Last Modified: 10/22/2014
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