Wave reworking of abandoned deltas

Authors

  • Jaap H. Nienhuis,

    Corresponding author
    1. Geology and Geophysics Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
    2. Water Engineering and Management Department, University of Twente, Enschede, Netherlands
    • Corresponding author: J. H. Nienhuis, Geology and Geophysics Department, Woods Hole Oceanographic Institution, 266 Woods Hole Rd., MS #22, Woods Hole, MA 02543, USA. (jnienhuis@whoi.edu)

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  • Andrew D. Ashton,

    1. Geology and Geophysics Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
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  • Pieter C. Roos,

    1. Water Engineering and Management Department, University of Twente, Enschede, Netherlands
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  • Suzanne J. M. H. Hulscher,

    1. Water Engineering and Management Department, University of Twente, Enschede, Netherlands
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  • Liviu Giosan

    1. Geology and Geophysics Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
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Abstract

[1] River deltas and individual delta lobes frequently face reduction of sediment supply, either from the geologic process of river avulsion or, more recently, due to human activities such as river damming. Using a process-based shoreline evolution model, we investigate wave reworking of delta shorelines after fluvial input elimination. Model results suggest that littoral sediment transport can result in four characteristic modes of delta abandonment, ranging from diffusional smoothing of the delta (or delta lobe) to the development of recurved spits. A straightforward analysis of delta shape and wave characteristics provides a framework for predicting the mode of delta abandonment. The observed morphologies of historically abandoned delta lobes, including those of the Nile, Ebro, and Rhone rivers, fit within this framework. Our results provide quantitative insight into the potential evolution of active delta environments in light of future extreme reduction of fluvial sediment input.

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