Estimativas de produção de sedimentos por erosões lineares nas microbacias do Ribeirão da Rancharia e Ribeirão do Bugio-São Paulo

Abstract

The hydrographical basin located in urban areas in São Paulo State, next of water sheds of the Paranapanema and Peixe River basins, present many foci of large erosions. The greenbasin of Ribeirao da Rancharia has 3 urban erosions and 22 large rural erosions and the microbasin of the Bugio Stream, in Quata, has 26 rural erosions and an urban gully. From the areas of the previously mapped urban gullies and an average area of 500 m² for rural erosions, the volume and soil density of 1.55 g/cm³, soil losses were estimated in both watersheds. The estimated production of sediments in the basin in Rancharia was 17,350 t/year and in the watershed in Quata it was 144,340 t/year, and the urban gully of Quatá was responsible for 95% of the sediments produced in the microbasin of the Bugio River. In the case of Rancharia, the urban erosion control works and the distance from the watershed contributed to the stability of the urban gullies, and the estimates between the urban and rural areas were divided.