ABSTRACT: Modelling the response of sandy coasts to sea-level rise.

CGRG Bibliography of Canadian Geomorphology
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Consideration of the potential impact of sea-level rise on sandy coasts has been dominated by the conceptual model proposed by Bruun (1962) and the associated Bruun Rule which is used to predict the horizontal translation of the shoreline associated with a given rise in sea-level. Bruun's original model is based primarily on an assumption that a rise in sea level on a sandy coast leads to erosion of the beach, net sand transfer to the nearshore profile and deposition of a thickness of sediment equal to the rise in sea level. This assumption may not be justifiable and if it is not then there is no basis for the model itself. A key limitation of the initial assumption, and thus of the model, is that there is no consideration of the dune sediment budget, and the processes associated with beach/dune interaction. An alternative conceptual model is presented which is based on a two-dimensional equilibrium profile similar to that which forms the basis for the Bruun Model. The proposed model incorporates consideration of the dune sediment budget and foredune dynamics. It predicts no net transfer of sediment to the nearshore profile as well as preservation of the foredune through landward migration. The proposed model offers a better starting point for developing more realistic models of shoreline response to sea-level rise and is likely to offer a better explanation of the true behaviour of sandy beach systems. Testing of the validity of the model and its potential use for integrated coastal zone management will require consideration of the volume changes associated with sea level rise on a decadal scale.

Bibliography of Canadian Geomorphology