The effect of flood intermittency on bifurcations in fluviodeltaic systems: Experiment and theory

Max S. Daniller-Varghese, Wonsuck Kim, David C. Mohrig

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


The dimensions and organization of deltaic islands and channels dictate delta morphology. This study presents experimental results modelling deposition at a river mouth and flow bifurcation around delta islands. Mouth bar formation and channel bifurcation is achieved in a laboratory setting by alternating input of suspended load transport and bedload transport. These two modes of transport produce two characteristic deposits with different advection lengths. Suspended load transport creates a steep deposit far from the inlet, while bedload creates a low angle, levéed deposit near the inlet. This study found that flow bifurcations occur where the proximal and distal deposits encroach on one another; and determined that there is a relationship between the frequency of suspended load transport and the length to channel bifurcation. Frequent flooding causes shorter length to bifurcations, whereas infrequent flooding causes greater length to bifurcations. This work overturns the hitherto understood mechanism of bifurcation location as a function of only high-transport conditions. Instead, the interactions between the sediment transport and deposition from normal flow and large-scale flooding events dictate delta island morphology.

Original languageEnglish
Pages (from-to)3055-3066
Number of pages12
Issue number6
Publication statusPublished - 2020 Oct 1

Bibliographical note

Funding Information:
The authors gratefully acknowledge Indre Altman, James Buttles and Brandon Minton their assistance in the lab and for fruitful discussions. The authors also wish to thank Anastasia Piliouras, John Shaw, Paola Passalacqua, and Doug Edmonds for lively conversation and continuous feedback. Additionally, the authors thank Katherine Ratliff, Brad Murray, Venkappayya Desai, anonymous reviewers, and the journal editors and staff whose thoughtful and thorough suggestions improved this paper. Support was provided by the National Science Foundation (EAR‐1324334, EAR‐1324760).

Publisher Copyright:
© 2020 The Authors. Sedimentology © 2020 International Association of Sedimentologists

All Science Journal Classification (ASJC) codes

  • Geology
  • Stratigraphy


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