Network response to disturbances in large sand-bed braided rivers
The reach-scale effects of human-induced disturbances on the channel network in large braided rivers are a challenge to understand and to predict. In this study, we simulated different types of disturbances in a large braided river to get insight into the propagation of disturbances through a braid...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-01-01
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| Series: | Earth Surface Dynamics |
| Online Access: | http://www.earth-surf-dynam.net/4/25/2016/esurf-4-25-2016.pdf |
| Summary: | The reach-scale effects of human-induced disturbances on the
channel network in large braided rivers are a challenge to understand
and to predict. In this study, we simulated different types of disturbances in a large braided river to get insight into the propagation of disturbances through a braided
channel network. The results showed that the disturbances initiate
an instability that propagates in the downstream direction by means of
alteration of water and sediment division at bifurcations. These
adjustments of the bifurcations change the migration and shape of bars,
with a feedback to the upstream bifurcation and alteration
of the approaching flow to the downstream bifurcation. This way, the
morphological effect of a disturbance amplifies in the downstream
direction. Thus, the interplay of bifurcation instability and
asymmetrical reshaping of bars was found to be essential for
propagation of the effects of a disturbance. The study also
demonstrated that the large-scale bar statistics are hardly
affected. |
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| ISSN: | 2196-6311 2196-632X |