The Influence of Spatially Varying Supply on Coastal Aeolian Transport: A Field Experiment

Abstract

Abstract:The development of dunes is characterized by the alternating effects of erosion during storm events and growth during milder conditions. The quantification of dune growth due to aeolian processes has received some attention but uncertainty remains on where the dune sand, which accommodates growing dunes, originates from in the coastal profile. In this paper we hypothesize that sediment eroded from the upper beach is the main sediment supply for aeolian sediment transport governing dune growth. To test this hypothesis we have analyzed morphological profiles collected monthly at three different field sites (Noordwijk, Vlugtenburg and Narrabeen) during several years. No significant erosive trend due to aeolian processes was found at the upper beach at this temporal resolution. We conclude that it is highly unlikely that the main supply for aeolian sediment transport governing dune growth was located at the upper beach. The intertidal zone might be a relevant alternative source of sediment in the cross shore profile.

Longshore Transport Variability of Beach Face Grain Size: Implications for Dune Evolution

“…The reference point is located within the area where sediment is supplied to the beach under accreting conditions and can thereby signify whether the beach is supplied with sediment in the appropriate grain-size range for aeolian transport and dune formation (de Vries et al, 2014;Hoonhout, de Vries, and Cohn, 2015). The range of dune-building grain sizes depends on several site-specific factors (e.g., wind climate, surface moisture, vegetation, and topography) (Bauer et al, 2009;Wiggs, Baird, and Atherton, 2004).…”