Sediment budget controls on foredune height: Comparing simulation model results with field data |
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| Authors: | Robin Davidson‐Arnott Patrick Hesp Jeff Ollerhead Ian Walker Bernard Bauer Irene Delgado‐Fernandez Thomas Smyth |
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| Institution: | 1. Department of Geography, University of Guelph, Guelph, ON, Canada;2. College of Science and Engineering, Flinders University, Bedford Park, South Australia, Australia;3. Department of Geography and Environment, Mount Allison University, Sackville, NB, Canada;4. School of Geographical Sciences and Urban Planning, School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA;5. Earth, Environmental and Geographic Sciences, University of British Columbia, Okanagan, Kelowna, BC, Canada;6. Department of Geography, Edge Hill University, Ormskirk, Lancashire, UK;7. Department of Geography and Environmental Science, Liverpool Hope University, Hope Park, Liverpool, UK |
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| Abstract: | The form, height and volume of coastal foredunes reflects the long‐term interaction of a suite of nearshore and aeolian processes that control the amount of sand delivered to the foredune from the beach versus the amount removed or carried inland. In this paper, the morphological evolution of more than six decades is used to inform the development of a simple computer model that simulates foredune growth. The suggestion by others that increased steepness of the seaward slope will retard sediment supply from the beach to the foredune due to development of a flow stagnation zone in front of the foredune, hence limiting foredune growth, was examined. Our long‐term data demonstrate that sediment can be transferred from the beach to the foredune, even with a steep foredune stoss slope, primarily because much of the sediment transfer takes place under oblique rather than onshore winds. During such conditions, the apparent aspect ratio of the dune to the oncoming flow is less steep and conditions are not as favourable for the formation of a stagnation zone. The model shows that the rate of growth in foredune height varies as a function of sediment input from the beach and erosion due to storm events, as expected, but it also demonstrates that the rate of growth in foredune height per unit volume increase will decrease over time, which gives the perception of an equilibrium height having been reached asymptotically. As the foredune grows in size, an increasing volume of sediment is needed to yield a unit increase in height, therefore the apparent growth rate appears to slow. Copyright © 2018 John Wiley & Sons, Ltd. |
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| Keywords: | foredune evolution beach– dune interaction computer simulation limits to foredune height |
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