In this paper combine the knowledge of erosion and accretion zones along of 630-km long shorernof the Rio Grande do Sul state (Brazil) and data from mathematical estimation of the regional longshorerntransport potential. The erosion zones were defined comparing shorelines mapped using DGPS. Thernsediment transport estimation, based on the CERC formula, predicts a substantial variation of the energyrnflux into the surf zone due to little changes in the shoreline orientation. Erosion was observed along coastalrnstretches areas correspond to the stretches coast where there is an increase on the longshore flux energy.rnDette (2001), suggests that a reduction in the flux due to changes in the shoreline alignment implies a jam inrnthe longshore transport. It means that part of the sediment arriving the upstream stretch must be depositedrnor diverted in offshore direction. Satellite images and bathymetric maps clearly show, in such area, therncombination of two process: a strong alongshlef jet and the shoreface accretion up to 2 km offshore, near tornthe 10 m isobath.
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