This paper deals with the sedimentation and erosion dynamics of a sand-ridge on the Maçaguaçu River mouth on the São Paulo coastal plain, north of Caraguatatuba Bay. Sedimentological, climatic and hydrodynamic data were analysed from an integrative point of view, considering relationships between continental and marine antagonic forces. Even if incomplete these preliminary observation show that erosion only occurs when more intense rains and higher tidal cycles coincide and that even the intense occurrence of one of these phenomena is not enough to trigger the destructive processes.
Maçaguaçu river; fluvial morphology; coastal erosion; sediments; tides; rainfall; winds