English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

River floods are usually featured by a downstreamflattening discharge peak whereas a downstream increasing discharge peak isobserved at a rate exceeding the tributary discharge during highlysilt-laden floods (hyperconcentrated floods) in China's Yellow River. Itentails a great challenge in the downstream flood defence and the underlyingmechanisms need to be unravelled. Previous study on this issue only focuseson one possible mechanism, while the present work aims to reveal therelative importance of bed roughness change and bed erosion in thehyperconcentrated flood. Using a newly developed fully coupled morphodynamicmodel, we have conducted a numerical study for the 2004 hyperconcentratedflood in the Xiaolangdi-Jiahetan reach of the Lower Yellow River. In orderto focus on the physical mechanism and to reduce uncertainty fromlow-resolution topography data, the numerical modeling was carried out in aschematized 1-D channel of constant width. The basic understanding that bedroughness decreases with concentration at moderate concentrations (e.g.several 10 s to 100 s g L<sup>−1</sup>) was incorporated by a simple power-law relationbetween Manning roughness coefficient and sediment concentration. Thefeedback between the bed deformation and the turbid flow, however, was fullyaccounted for, in the constituting equations as well as in the numericalsolutions. The model successfully reproduced the downstream flood peakincrease for the 2004 flood when considering the hyperconcentration-inducedbed roughness reduction. As the hyperconcentration lags shortly behind theflood peak, later parts of the flood wave may experience less friction andovertake the wave front, leading to the discharge increase. In comparison,bed erosion is much less important to the discharge increase, at least forhyperconcentrated flood of moderate sediment concentration

Relative role of bed roughness change and bed erosion on peak discharge increase in hyperconcentrated floods