[1] Wave-current interactions play a major role in the dynamics of shallow tidal inlets. This study investigates these interactions at a natural inlet, with a strong focus on current-induced changes on wave propagation. The analysis of hydrodynamic data collected at the Albufeira lagoon, Portugal, revealed spatiotemporal variations of water levels and wave heights along the inlet, attributed to wave-current interaction processes. We compared the simulations of a coupled wave-circulation modeling system, computed with and without waves, and propagated with and without current feedback. The wave-induced setup inside the lagoon represented 7%-15% of the offshore significant wave height. The accuracy of the wave's predictions improved when current feedback was included. During ebb, the currents increased the wave height at the mouth of the inlet (up to 20%) and decreased the wave height in the inlet (up to 40%), due to current-induced refraction, steepness dissipation, and partial blocking. During flood, the currents decreased the wave height in the inlet (up to 10%) and increased the wave height at the exterior parts of the ebb shoal (up to 10%), due to current-induced refraction. These effects significantly attenuate seaward sediment fluxes during ebb and contribute to the sediment accretion in the inlet.Citation: Dodet, G., X. Bertin, N. Bruneau, A. B. Fortunato, A. Nahon, and A. Roland (2013), Wave-current interactions in a wave-dominated tidal inlet,

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The effects of tidal flats on the hydrodynamics of the Tagus estuary are analysed using an accurate highresolution shallow water model, supported by field data. Tidal flats act mainly as energy filters, rather than sinks, transferring energy from astronomic to non-linear frequencies. They also play a major role in determining the strong resonance mode that amplifies semi-diurnal constituents. We show that the upper estuary, with extensive tidal flats, has an increasing accretion rate. This "filling-up" results from a positive feedback between sediment deposition and the hydrodynamics: accretion in the upper estuary lengthens the duration of ebbs, decreasing sediment flushing and further increasing accretion. 0 Elsevier, Paris / Ifremer / Cnrs / Ird tidal flats / tidal propagation / numerical model / Tagus estuary RCsumC-Sur l'effet des estrans sur l'hydrodynamique de l'estuaire du Tage. Les effets des estrans sur l'hydrodynamique de l'estuaire du Tage sont analysCs B travers un modtile d'Ccoulement de haute r&olution, et des donnCes de terrain. Les estrans fonctionnent surtout comme des filtres d'Cnergie, et non pas comme des dissipateurs, transfkrant 1'Cnergie des frkquences astronomiques 5 des frkquences non-lintaires. Les estrans ont aussi un rale t&s important dans la ddtermination du mode de rCsonance qui amplifie les constituantes semi-diumes. Nous montrons que la partie sup&ieure de l'estuaire, dominCe par des estrans, a un taux de stdimentation croissant. Ceci est d0 B une r&o-action positive entre le dtp6t de stdiments et l'hydrodynamique : le dkp& dans la partie supt%ieure de l'estuaire augmente la dun% des reflux de marCe, rkduisant le transport de sCdiments vers l'extkrieur, et contribuant ainsi ti leur accumulation dans l'estuaire.