Avaliação prospectiva dos cenários futuros das mudanças climáticas e do uso e ocupação do solo no volume do reservatório Epitácio Pessoa

Abstract

The semi-arid region of Brazil is one of the most affected by water scarcity, mainly due to high evapotranspiration rates and several drought events. Therefore, studies related to changes in the behavior of water volume in reservoirs are extremely important. In this context, the objective of this study was to evaluate the behavior of the water volume of the Epitácio Pessoa reservoir considering future climate scenarios, changes in land use and coverage, and population growth. The study consisted of the following methodological steps: (a) estimation of water consumption for future human supply from 2030 to 2060, (b) analysis of changes in land use and land cover for the years 1987, 2001 and 2018 in the basin, (c) prediction of land use and land cover for 2060 in the Epitácio Pessoa reservoir basin using the MLP neural network-based model, (d) calibrating and validating the SWAT hydrological model for the periods 1997−2010 (calibration) and 2011−2017 (validation), (e) analyzing the variability of temperature and precipitation between 2030 and 2060, based on the climate change scenarios and models projected by the IPCC, (f) simulating the inflows of the Epitácio Pessoa reservoir from 2030 to 2060 with the SWAT hydrological model, and (g) estimating the water volume of the reservoir. Epitácio Pessoa from 2030 to 2060. The results obtained showed a predisposition for an increase in the agriculture and pasture class, and a significant reduction in the open shrubby caatinga class by the year 2060. Climate change projections showed that for the driest periods, the MCA predicts even drier months in the basin, with the months from September to November being the most critical. The high emissions scenario (SSP5-8.5) estimates higher temperatures for all models analyzed, with a maximum temperature around 34ºC, with December being the hottest month. In most months, the GFDL-ESM4 model presented higher values for maximum temperature in the basin. The hydrological modeling showed results considered satisfactory, with R² and Nash above 0.5, especially in the calibration and validation stage of the Caraúbas station. Considering the increased average flow of the PISF, the population growth of 26.37% and water consumption of 214,735.98 m³/day for 2060, the study showed critical periods between the years 2042 to 2049, with water quantity below the dead volume. In addition, the SSP5-8.5 scenario still predicts a critical situation for the year 2059.