Sand dune definition

There are many definitions of what constitutes a sand dune, those given below are principally derived from considering their geomorphological development. The definitions given below are intended to cover the types most frequently encountered in coastal locations in northwest Europe.

Definition from the UK Biodiversity Action Plan

"Coastal sand dunes develop where there is an adequate supply of sand (sediment within the size range 0.2 to 2.0 mm) in the inter tidal zone and where onshore winds are prevalent. The critical factor is the presence of a sufficiently large beach plain whose surface dries out between high tides. The dry sand is then blown landwards and deposited above high water mark, where it is trapped by specialised dune-building grasses which grow up through successive layers of deposited sand."

Definition from coastal conservation handbook

"Sand dunes develop wherever there is a suitable supply of sediment within the size range 0.2 to 2.0 mm. The form of the dune depends on the amount of available sediment and the ease with which it can be moved by the wind. Wet sand usually remains in situ. Thus sand dunes may be defined as: areas where wind blown sand is deposited inland from a wide beach which dries out periodically between high tides" (Doody 2001).

References

Doody, J.P. 2001. Coastal Conservation and Management: an Ecological Perspective. Kluwer, Academic Publishers, Boston, USA, 306 pp. Conservation Biology Series, 13