Short-term morphodynamic changes in a fetch limited beach at the Ebro delta (Spain), under low wave-energy conditions

C.MÖSSO, J.SIERRA, V.GRACIA, M.MESTRES ; A RODRIGUEZ

JOURNAL OF COASTAL RESEARCH

COASTAL EDUCATION & RESEARCH FOUNDATION

Lugar: Florida; Año: 2011 vol. SI64 p. 185 - 189

0749-0208

Sandy beaches in fetch-limited environments are protected from large ocean-generated swell waves, and fetchcharacteristics allow local wind-generated waves and currents to develop and drive the main morphodynamicprocesses. The morphodynamics of these low-energy beaches present a peculiar behaviour since there is not adominant forcing mechanism inducing the beach changes. The main objective of this work is to describe andquantify the observed morphodynamic changes at the barred, quasi longshore-uniform beach of the TrabucadorBar at the Ebro Delta (Spain) under low-energy conditions. A nine-day field campaign was carried out within theframework of the European project FANS (Fluxes Across Narrow Shelves. The Ebro Delta Case) supported bythe EC MAST-III Research Programme, (Contract No. MAS3-CT95-0037, DG12 ? ESCY) and themeasurements included a detailed topo-bathymetric surveying at the beginning and at the end of the campaign,video recordings covering the whole domain of the study area, surf zone waves and currents time series obtainedat different positions and depths, nearshore pressure and horizontal velocities time series outside the surf zone.The results show that the beach underwent important longshore and cross-shore (the breaching of the submergedbar) morphodynamic changes under low-energy conditions. The observations suggest that the low-energy wavefield and the beach profile played a key role in the generation of low frequency oscillations and rip currents thatreshaped the whole study zone.