Vegetation coverage in hydrographic basins in the central region of the State of São Paulo, Brazil

Vegetation coverage can be inappropriately used, especially in the absence of proper planning, and can result in a reduction of the occupied area. Demographic and economic alterations are factors that contribute to the degradation of vegetation coverage in landscape units. In addition, because vegetation is essential for protection of recharge areas in aquifers, the fragmentation of habitats in hydrographic basins causes changes in climate temperature, soil erosion, eutrophication, and siltation of watercourses. This study analyzed the vegetation coverage from the municipality of São Carlos, State of São Paulo (SP) to assess the environmental quality of water resources in the hydrographic basins and sub-basins, in the Guarani Aquifer System. The vegetation coverage was analyzed in three scales: municipality, Hydric Resource Management Units (UGRHIs), and hydrographic sub-basins based on map overlapping from the LAPA/UFSCar Digital Cartographic Collection and visual interpretation of LANDSAT 5, TM sensor, Path 220, row 075 on satellite images. The municipality of São Carlos has vegetation coverage of 31,776.4 hectares, in which 57% is classified as preserved vegetation typology, and 58% is over the Guarani aquifer recharge area. The vegetation coverage with savannas, riparian forests, and mesophyll forests represented 28% of the total studied area and is located over 28.3% of the Guarani aquifer recharge area extension. The Permanent preservation areas (PPAs) represent 21.6% of the total vegetation coverage with 51% of it being vegetated. The municipality has a total of 686 springs (Topographic maps of IBGE, escale 1:50,000) distributed on an average of 60 springs per km2; 40% of these are protected by vegetation.