Análise da disponibilidade hídrica da bacia do rio Preto, Bahia, com base em estudo hidrológico e nas outorgas de uso da água

Abstract

In the last few years, there has been a considerable advance in the occupation of man in hydrographic basins in order to develop irrigation, industry, animal husbandry activities, among others. As a result, several jobs are generated, as well as the production of food and materials. On the other hand, the consumption and waste of water captured in rivers and aquifers increases, which leads to changes in the region's hydrological cycle. The present work aims to carry out a hydrological study in the Rio Preto basin, located in the western region of the state of Bahia. For such purposes, it was necessary to identify and delimit the basin, using the QGIS software, and later, observe the behavior of rainfall and streamflow over time through statistical tests, whose data were obtained on the Hidroweb platform by the National Water Agency (ANA). The tests proved that the flow has been showing a significant decrease regardless of precipitation. In this context, an attempt was made to assess the water availability of the basin by determining the reference flow Q90% as a criterion for water use permits issued by the Institute of the Environment and Water Resources of Bahia (INEMA). The results showed that irrigation is responsible for 99.34% of the flows captured superficially and for 97.67% of the flows captured underground. In addition, the granted flows accumulated over time showed an significant increase in the last 10 years, being able to reach, in 2029, the limit of 80% of the reference flow, compromising the water sustainability of the region.