Erosion of Cohesive Sediments: Resuspension, Bed Load, and Erosion Patterns from Field Experiments

K. Debnath, Vladimir Ivanovich Nikora, J. Aberle, B. Westrich, M. Muste

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

New field data on cohesive sediment erosion is presented and discussed, with particular focus on partitioning the total erosion into resuspension and bed load. The data were obtained using a recently developed in situ flume of the National Institute of Water and Atmospheric Research, New Zealand. The erosion rate is estimated from direct measurements of bed surface elevations by acoustic sensors, whereas resuspension rate is obtained using data on sediment concentrations measured by optical backscatter sensors. The bed- load contribution to the total erosion rate is evaluated from the conservation equation for sediments. To test repeatability, the data from the in situ flume are compared with those from a previous version of the flume. The results show that comparative studies of in situ flumes and standardized deployment procedures enable direct comparison of experimental data on cohesive sediment erosion. Overall, the data show that a commonly used assumption that the erosion rate is equal to the resuspension rate is not always valid as bed load plays a significant role in cohesive sediment erosion. The data also highlight the importance of clay content and other sediment physical characteristics in the sediment mixture.
Original languageEnglish
Pages (from-to)508-520
Number of pages13
JournalJournal of Hydraulic Engineering
Volume133
Issue number5
DOIs
Publication statusPublished - May 2007

Keywords

  • in-situ measurements
  • shear-stress
  • intertidal sediments
  • mud/sand mixtures
  • fine sediment
  • annular fume
  • sea carousel
  • aggregation
  • instrument
  • transport

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