Available Sediment Supply Reworked as Megaripples by Tidal Currents in Sheltered Flats; Gulf of Gabes, Tunisia

The sheltered tidal flat of El Gala coast in the Gulf of Gabes has experienced profound morphologic change illustrated by the genesis of a wide marsh domain at the upper limit of the foreshore. This flat is marked by a sufficient sediment supply leading to a regular expansion of the marsh domain. Sediment availability is illustrated by the development of the high regime sedimentary structure like the megaripples. Hydro-sedimentary processes are governed occasionally by violent energy tied to tidal currents. During spring tide, velocity of the ebb tidal current outpaces 40 cm/s, and such energy is needed to perform megaripples like car wheel features. These structures with 20–55 cm in radius invoke that the hydrodynamic conditions are marked by an increased velocity during the ebb tide period. This current is accelerated by the substrate slope angle.