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Evaluation of bankfull stage from plotted channel geometries

Citation

Keast, D and Ellison, JC, Evaluation of bankfull stage from plotted channel geometries, Journal of Hydrology: Regional Studies, 41 Article 101052. ISSN 2214-5818 (2022) [Refereed Article]


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Copyright Statement

2022 Published by Elsevier B.V. This is an open access article under the Creative Commons Attribution 4.0 International (CC BY-NC-ND 4.0) license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

DOI: doi:10.1016/j.ejrh.2022.101052

Abstract

Study region

North-eastern Tasmania, Australia.

Study focus

Two quantitative methods for determining the bankfull stage of alluvial rivers from plotted channel cross-sections were assessed. Bankfull stage estimates determined using the minimum width-to-depth ratio and the first maximum of the bench-index were compared, and then evaluated against qualitative estimates of bankfull stage, using data from 89 cross-sectional surveys along nine alluvial river reaches in north-eastern Tasmania.

New hydrological insights for the region

The minimum width-to-depth ratio was found to provide lower estimates of bankfull stage than the bench-index, with an overall mean ratio between the two methods of 0.84. Qualitative estimates of bankfull stage generally fell between those provided by the two models, with the minimum width-to-depth ratio performing better when assessed against qualitative estimates. These results show that while neither method provides a suitable stand-alone means for estimating bankfull stage, in combination they provide an effective means to approximate the range of bankfull stage. The high variability in bankfull stage found along a reach in this study indicates that where possible bankfull stage is best determined at the reach rather than single cross-sectional scale. Bankfull stage should be presented as a range of values with associated confidence intervals rather than as a finite result, with definition of bankfull stage estimates and sample number also reported.

Item Details

Item Type:Refereed Article
Keywords:river channel, cross-section, river reach, bankfull stage, Tasmania, Australia
Research Division:Earth Sciences
Research Group:Physical geography and environmental geoscience
Research Field:Geomorphology and earth surface processes
Objective Division:Environmental Management
Objective Group:Fresh, ground and surface water systems and management
Objective Field:Assessment and management of freshwater ecosystems
UTAS Author:Keast, D (Mr David Keast)
UTAS Author:Ellison, JC (Associate Professor Joanna Ellison)
ID Code:149805
Year Published:2022
Deposited By:Geography and Spatial Science
Deposited On:2022-04-14
Last Modified:2022-05-23
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