|Morphodynamics of a swash bar in the context of the evolution of a swash platform associated to an ebb delta|
Balouin, Y.; Howa, H. (2000). Morphodynamics of a swash bar in the context of the evolution of a swash platform associated to an ebb delta, in: Trentesaux, A. et al. (Ed.) Marine Sandwave Dynamics, International Workshop, March 23-24 2000, University of Lille 1, France. Proceedings.
In: Trentesaux, A.; Garlan, T. (Ed.) (2000). Marine Sandwave Dynamics, International Workshop, March 23-24 2000, University of Lille 1, France. Proceedings. Université de Lille 1: Lille. ISBN 2-11-088263-8. 240 pp., more
|Authors|| || Top |
Within the European MAST III - INDIA Project, the westerly tidal inlet cutting through the barrier island system of the Ria Formosa (South Portugal) was studied during an important fieldwork from January to March 1999. Morphodynamics of the updrift swash platform associated to the ebb delta was described (Balouin et al., in press) and revealed a rapid migration toward the inlet under waves and tidal current action. Moreover evidences for sedimentary exchanges were described, and the longshore drift supply was quantified. The present study focuses on the main swash bar of this system which dynamics was investigated by a multidisciplinary approach: hydrodynamics, sediment fluxes (fluorescent tracers experiments), grain size trend analysis. Combination of these methods permits to quantify morphodynamics of this part of the swash platform. Hydrodynamics over this bar is dominated by the flood current which is longer and stronger. This flood current combined with waves meanly from West yields a sediment transport toward the inlet. The grain size trend analysis shows that the transport in this area is important and homogenous over the bar. This sediment transport is quantified by a fluorescent tracer experiment which gives a sediment displacement of 14 m in one tide toward the inlet. The grain size trend analysis allows the estimation of the width of the area concerned by this direction of transport, and permits to calculate the sediment flux toward the inlet. This study permitted to validate a theoretical formulation of sediment transport over the swash bars of this swash platform.