AN OVERVIEW OF THE BRITISH BEACH AND NEARSHORE DYNAMICS (B-BAND) PROGRAMME

M.A. Davidson, P.E. Russell, D.A. Huntley, J. Hardisty, A. Cramp

Abstract


The British Beach And Nearshore Dynamics (B-BAND) programme is a three year collaborative research project aimed at improving understanding of surf zone sediment transport processes. Field studies were carried out on dissipative, intermediate and reflective beaches during both neap and spring tides (tidal range up to 9m), and during storm wave (Hb > 3m) conditions. The field research system comprises up to 7 pressure transducers (PT's), 11 electromagnetic current meters (EMCM's) and 12 optical backscatter sensors (OBS's). The focal point of the instrument array was a 1600m2 box which was instrumented at each corner and designed to allow the calculation of alongshore and cross-shore suspended sediment fluxes through the box. The largest sediment transport rates (up to 0.6 kgm"V) occurred in the inner surf zone of the dissipative beach during storm conditions and showed strong offshore-directed sand transport at infragravity frequencies. The extent to which infragravity oscillations developed was seen to vary inversely with the degree of beach reflectivity, and directly with the incident breaker height. Sediment transport patterns often exhibited strong tidal asymmetry, attributed to the effects of beach dewatering and to a lag between hydrodynamics and bedform alteration.

Keywords


nearshore dynamics; B-BAND; United Kingdom

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