MULTI-TEMPORAL ANALYSIS OF LAND USE AND VEGETATION COVER IN SÃO FRANCISCO DO SUL AND ITAPOÁ, SANTA CATARINA STATE - BRAZIL: IMPLICATIONS TO GROUNDWATER CONTAMINATION

Abstract

By means of the multitemporal approach, we analyze the changes in land use and vegetation cover in the São Francisco do Sul and Itapoá municipalities, located in the northern coast of the State of Santa Catarina, Brazil. LANDSAT satellite images from 1991 to 2019 were analyzed and classified into four classes of soil use and occupation (vegetated area, bare soil, urbanized area, and water body) by the GEOBIA method. Weighted sum analysis was applied to the ‘urbanized area’ class and the data available on geologic units, so as to identify areas vulnerable to groundwater contamination. The vegetated areas of São Francisco do Sul and Itapoá have diminished along the 2000’s, but recovery measures, such as reforesting and restraint of soil exposure, have been adopted, with 89.61% success. The urban zone has increased 3.36% in the last 28 years. The achieved overall accuracy for the classification was of 79.33% and the Kappa coefficient was 0.69. The analysis of groundwater vulnerability to contamination helped identify regions more susceptible to pollution, which coincide almost entirely with those where urbanization was more intense in areas where unconsolidated sediments predominate.