| ID |
2040 |
| Citation |
Green, K., Brardinoni, F. and Y. Alila, 2014. Patterns of bedload entrainment and transport in forested headwater streams of the Columbia Mountains, Canada. Earth Surface Processes and Landforms Special Issue: Morphodynamics of steep mountain streams, 40 (4):427-446. DOI: 10.1002/esp.3642 |
| Organization |
University of British Columbia; University of Milano-Bicocca |
| URL |
http://onlinelibrary.wiley.com/doi/10.1002/esp.3642/full |
| Abstract/Description or Keywords |
We monitor bedload transport and water discharge at six stations in two forested headwater streams of the Columbia Mountains, Canada. The nested monitoring network is designed to examine the effects of channel bed texture, and the influence of alluvial (i.e._step pools and riffle pools) and semialluvial morphologies (i.e._boulder cascades and forced step pools) on bedload entrainment and transport. Results indicate that dynamics of bedload entrainment are influenced by differences in flow resistance attributable to morphology. Scaled fractional analysis shows that in reaches with high form resistance most bedload transport occurs in partial mobility fashion relative to the available bed material, while calibers finer than 16_mm attain full mobility during bankfull flows. Equal mobility transport for a wider range of grain sizes is achieved in reaches exhibiting reduced form resistance. Our findings confirm that the Shields value for mobilization of the median surface grain size depends on channel gradient and relative submergence; however, we also find that these relations vary considerably for cobble and gravel bed channels due to proportionality between dimensionless shear stress and grain size. Exponents of bedload rating curves across sites correlate most with the D90s of the mobile bed, however, where grain effects are controlled (i.e._along individual streams), differences in form resistance across morphologies exert a primary control on bedload transport dynamics. Application of empirical formulae developed for use in steep alpine channels present variable success in predicting transport rates in forested snowmelt streams. Formulae that explicitly account for reductions in mobile bed area and high morphological resistance associated with woody debris provide the best approximation to observed empirical data. bedload entrainment; bedload transport; resistance to flow; rating curves; transport formulae |
| Information Type |
Article |
| Regional Watershed |
Columbia River |
| Sub-watershed if known |
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| Aquifer # |
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| Comments |
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| Project status |
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| Contact Name |
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