摘要：Sediments collected from the nearshore, at the beach of the Gulf of Tunis, are used to understand the complex interactions between the grain-size pattern and the hydrodynamic process, under urban and natural effects. Generally, the nearshore sediment of the Gulf of Tunis has an average mean diameter of 0.35-0.085 mm while the coastline sediment is 0.25 mm, on an average. The grain size shows a coarsening trend at the beach slope, as a result of the action of the cross-shore current. On the other hand, the coarsening trend in the mean grain size is locally distorted at river mouths, sandy spits and harbor structures. Although the shoreline has been modified by human activity, the Gulf of Tunis has retained its natural configuration. The north-east and eastern longshore drift were interrupted by the sedimentary cell; which seems to be the factor for the bimodality of the grain population.
