As ilhas "hidro-pedo-geológicas" no contexto da região Semiárida do Nordeste Brasileiro

Abstract

The semi-arid region of Northeast Brazil is a region marked by the scarcity of water resources, due to irregular rains, high rates of evapotranspiration and shallow soils with little water storage capacity in aquifers. In this context, understanding hydrology, soil, geology and pedology are essential to understanding the different areas of the Northeast. This region has different types of climate, ecological and geological diversity. The Northeast region is formed by two hydrogeological contexts: (a) crystalline basement (52.3%), with virtually impermeable rocks, and (b) sedimentary basin, such as sedimentary rocks (47.6%) where important aquifers occur. Thus, knowing the characteristics of geology is to demystify the effects of droughts that cover this region. In this sense, the objective of this study is to analyze the influence of hydro-pedo-geological islands on the availability of water in the semi-arid region of the Northeast with the application of hydrological modeling in the Salgado River Basin. In this work, the following methodological procedures were used: (a) on-site visits in the different hydrographic basins in Northeast Brazil, to analyze hydrological and geological differences, and (b) hydrological modeling techniques using the Soil and Water Assessment Tool mathematical model (SWAT), which uses physical parameters of the soil, precipitation, flow and other elements of the hydrological cycle to analyze the water balance in the soil in the crystalline and sedimentary portions. The results of the water balance were analyzed to understand the influence of infiltration and runoff in different geological formations in the semiarid region of Northeast Brazil. Based on the results obtained, the study confirmed that there are hydro-pedo-geological “islands” in several portions of the Semi-arid region of Northeast Brazil.