Experimental Investigation of Bedload Sediment Transport and Bed Evolution in Double-Peaked Hydrograph

Le Wang, Alan Cuthbertson, Deyu Zhong, Gareth Pender, Zhixian Cao

Research output: Contribution to conferencePaperpeer-review

Abstract

In natural rivers, significant bedload transport and variability in sediment bed geomorphology is generally observed to occur under unsteady flows, especially during flood events. In this study, a double-peaked hydrograph event, consisting of two identical and consecutive flood waves (i.e. sub-hydrographs), was performed in a large titling flume to investigate the behavior of bedload transport and response of sediment bed change within both uniform and fine-graded sediment beds, respectively. The results indicate that the total bedload transport rates for both uniform and fine-grained sediment beds tend to be reduced during the second sub-hydrograph, in comparison to the first sub-hydrograph, with more significant reductions observed to occur during the rising limb compared to the falling limb. In terms of fractional transport rates for the fine-graded sediment, the results also show that the bedload transport rates for the coarsest fraction are most significantly reduced in the second sub-hydrograph, compared to the first, during the rising limb. A similar overall trend is also shown for the corresponding fine and medium sediment fractions. In terms of the bed evolution over the duration of the double-peaked hydrograph, detailed measurement of bed surface elevation within both uniform and graded sediment beds runs reveal that the well-defined alternate bars are generated in uniform sediment bed, while only slight variations in elevation are found to occur in the fine-graded sediment bed with no indication of the generation of bed forms.
Original languageEnglish
Pages1-10
Number of pages10
Publication statusPublished - Aug 2017
Event37th IAHR World Congress - Putra World Trade Centre, Kuala Lumpur, Malaysia
Duration: 13 Aug 201718 Aug 2017
http://www.iahrworldcongress.org/index.php

Conference

Conference37th IAHR World Congress
CountryMalaysia
CityKuala Lumpur
Period13/08/1718/08/17
Internet address

Keywords

  • Bedload transport
  • Double-peaked hydrograph
  • Bed elevation
  • Uniform and graded sediments
  • Flume experiments

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