EFFECTS ON STREAMFLOW CAUSED BY REFORESTATION AND DEFORESTATION IN A BRAZILIAN SOUTHEAST BASIN: EVALUATION BY MULTICRITERIA ANALYSIS AND SWAT MODEL

Abstract. Deforestation is a global concern due to its problematic consequences, which intensify natural phenomena such as floods. In the past century, Brazil lost large areas of forests due to agricultural and livestock development, mining activities, the construction of hydroelectric plants and the expansion of the urban-industrial sector. The recovery of forests is an alternative to mitigate impacts caused by floods, although it is not known for sure the extent of such mitigation. The objective of this study was to assess the flow behavior of the Velhas River, Southeast Brazil, under different reforestation and deforestation scenarios, through multicriteria analysis and hydrological modeling. The combination of these methods allowed for interesting results, showing that a reforestation in 34.3% of the watershed area would have effects on river flow behavior similar to a reforestation of 9.2%. A scenario of deforestation in 100% of the forest area showed that there would be an increase in flow peaks in the rainiest months.