Sediment heterogeneity and mobility in the morphodynamic modelling of gravel-bed braided rivers

Umesh Singh, Alessandra Crosato, Sanjay Giri, Murray Hicks

Research output: Contribution to journalArticleScientificpeer-review

14 Citations (Scopus)
25 Downloads (Pure)

Abstract

The effects of sediment heterogeneity and sediment mobility on the morphology of braided rivers are still poorly studied, especially when the partial sediment mobility occurs. Nevertheless, increasing the bed sediment heterogeneity by coarse sediment supply is becoming a common practice in river restoration projects and habitat improvement all over the world. This research provides a step forward in the identification of the effects of sediment sorting on the evolution of sediment bars and braiding geometry of gravel-bed rivers. A two-dimensional morphodynamic model was used to simulate the long-term developments of a hypothetical braided system with discharge regime and morphodynamic parameters derived from the Waimakariri River, New Zealand. Several scenarios, differing in bed sediment heterogeneity and sediment mobility, were considered. The results agree with the tendencies already identified in linear analyses and experimental studies, showing that a larger sediment heterogeneity increases the braiding indes and reduces the bars length and height. The analyses allowed identifying the applicability limits of uniform sediment and variable discharge modelling approaches.

Original languageEnglish
Pages (from-to)127-144
Number of pages18
JournalAdvances in Water Resources
Volume104
DOIs
Publication statusPublished - 1 Jun 2017

Keywords

  • Delft3D
  • Graded sediment
  • Gravel-bed braided rivers
  • Meyer Peter and Müller formula
  • Morphodynamic modelling
  • Variable discharge

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