The present work aimed to evaluate the evolution degree ofthe relief in small hydrographical basins situated in the southwest area inSão Pedro do Sul-RS. Thirteen basins of third order of ramification wereanalyzed, being eight in the geomorphologic province area Depressão Periférica Sul-riograndense (Rio Grande do Sul Peripheral Depression) andfive in the area which is close to the edge of the plateau (Planalto) (transitionto plateaus and tablelands of Paraná basin). In order to prognosticate theonset of erosion processes, relief analysis techniques were used fromhypsometric and volumetric integrals, eroded matter ratio and relief rate.It was evidenced that basins close to the edge of the plateau showed higherrelief rate when compared to the basins in the peripheral depression area,reflecting the relation infiltration flowing and revealing higher pronenessto instability in these basins. However, it is to consider that some of theforms provided by the hypsometric curves in the peripheral depressionarea in Rio Grande do Sul are indicators of relief resulting from accumulationof sediment carried by the draining headwaters.
