Degradational response of engineered channels to changes in the upstream controls and channel width

Simplified 1D numerical simulations

Journal Article (2018)
Author(s)

Meles Siele (TU Delft - Rivers, Ports, Waterways and Dredging Engineering)

A Blom (TU Delft - Rivers, Ports, Waterways and Dredging Engineering)

E. Viparelli (University of South Carolina)

Research Group
Rivers, Ports, Waterways and Dredging Engineering
Copyright
© 2018 Meles Siele, A. Blom, Enrica Viparelli
DOI related publication
https://doi.org/10.1051/e3sconf/20184003035
More Info
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Publication Year
2018
Language
English
Copyright
© 2018 Meles Siele, A. Blom, Enrica Viparelli
Research Group
Rivers, Ports, Waterways and Dredging Engineering
Volume number
40
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Abstract

In response to changes in the upstream controls (i.e., the water discharge, the sediment supply rate, and the calibre of the load), engineered alluvial channels adjust their bed slope and bed surface texture to establish a new equilibrium state. Here we present and discuss various causes of degradational response of engineered channels to changes in the upstream controls and channel width. For that purpose, we apply a simplified 1D numerical research code to a schematic river reach of constant width consisting of mixed-size sediment, and assess its equilibrium state and transient response. We illustrate that the following perturbation to an initially equilibrium state lead to a degradational response: an increase of the water discharge, a decrease of the sediment supply rate, an increase of the sand content of the sediment supply, an increase of the gravel content of the sediment supply, and a decrease of the channel width. Degradational response under all conditions is associated with surface coarsening. The equilibrium states of the numerical simulations agree with analytical solutions. The results provide insight into the current degradational response of engineered rivers, such as the Rhine River, the Elbe River and the Danube River.