The short estuaries located on the English Channel and Atlantic coasts are distinguished by short-lived flood peaks and a very small average water discharge. Affected by large tide ranges during spring tides, they exhibit very different hydrosedimentological characteristics with low fluvial sediment input compared to marine sediment input. The formulation of a mathematical model for cohesive suspended matter transport and bottom evolution has necessitated a comparative study of bathymetric data and the recording of seasonal sediment movement in the Morlaix estuary.