Foredunes and blowouts: initiation, geomorphology and dynamics

This paper reviews the initiation, dynamics, geomorphology and evolution of incipient foredunes, established foredunes, and blowouts. Incipient foredunes may be initiated in a variety of ways leading to the fort-nation of ramps, terraces or ridges depending on progradation rates, vegetation type and cover, sediment transport rates and scale of erosional processes. Vegetation cover, morphology, growth rates, and types combine with aerodynamic processes to determine dune and swale morphology. Established foredunes are classified into five morpho-ecological types, and the flow behaviour over two types is detailed. A new model of foredune evolutionary paths at various possible time scales is presented. Blowout initiation, dynamics and sediment transport, and evolution is examined. Throughout the review, the gaps in present understanding of dune processes and a range of ideas for new research possibilities are provided. (C) 2002 Elsevier Science B.V. All rights reserved.