Efeitos de alterações de uso e ocupação do solo e de mudanças climáticas sobre o escoamento superficial na bacia experimental de Santana do Ipanema – Alagoas

Abstract

The semiarid region of Alagoas presents a serious panorama concernig water availability, due to an irregular distribution of rainfall, shallow soils and high evaporation rates. However, this region is deprived of information that helps analyzing and understanding the hydrological processes and their variables, through the application of methods that aim to optimize and better manage their water resources. The aim of this study was to predict the runoff for three settings of land use and occupation in the Experimental Basin Santana do Ipanema (BESI). The first setting considered the current use of the soil, the second setting considered the current use of land together with the conservation of Permanent Preservation Areas, as defined by Law nº. 4.771/65 and CONAMA Resolution 303/2002, and setting 3 considered climate change reports referenced by the Intergovernmental Panel on Climate Change - IPCC. The BESI is composed of three units of study: sub-basin 1 (0,127 km2), subbasin 2 (3.90 km2) and the watershed of 0,005 km2. In the model rainfall-runoff applied the model Kineros2 for ten precipitation events that occurred between the years 2007 and 2008, at the two sub-basins of BESI. The results for setting 1 always stood between the results for settings 2 and 3; setting 2 had the lowest volumes disposed and the highest volumes intercepted and infiltrated, while in setting 3 the relationship is inverted. It was noted that the two sub-basins the effect studied of deforestation of the land, scenario 3, leads to a considerable increase in the volume disposed, further contributing to water scarcity in the region, since there is a decrease in infiltration, and therefore in the recharge of the underground aquifer, which is responsible for maintaining the base flow in the months without rain.