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Where beach design is a key consideration, the use of BDMaT is a significant improvement on existing methods to ensure that the new beach-shape is in equilibrium with incident waves. Construction of beaches is a significant issue for design companies whose operations cover the Middle East, since there are major waterfront developments (such as Jumeirah Beach and Palm Island) that focus on beach frontages. There are also many applications around the UK – recently BDMaT has been used in the planning of Weymouth’s new marina beyond the existing ferry terminal.
Appropriate beach design helps avoid, or minimise, future maintenance needs by designing the initial beach plan-shape so that it remains in equilibrium under the incident wave climate. Stable beach plan-shapes, i.e. those with little movement of the beach contours over time, tend to evolve where a sandy beach is held between two erosion resistant headlands. These are called crenulate bays, or embayments.
The parabolic bay shape equation, out of several empirical equations, is the most widely used for evaluating beach stability and for predicting shoreline changes arising from structures built on a shoreline. Until now, its application has largely been a repetitive, labour-intensive manual process. With the use of BDMaT the design process can be quickly completed, and the output generated in ArcGIS.
Caption (above):
Folkestone, Kent:- the equilibrium beach plan shape has been plotted using BDMaT based on the incoming wave direction and diffraction due to coastal structure (both natural or man-made) such as headlands and groynes.
For further information, please contact Jonathan Kemp, Coasts & Estuaries Group, HR Wallingford
(01491 822412; E-mail jak@hrwallingford.co.uk).
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