Hydrological Impacts of Climate Change in the Semi-Arid Region: Modeling the Regulated Flow of the Armando Ribeiro Gonçalves Reservoir
water security, water resources management, climate change
This study aims to assess the impacts of climate change on the maintenance of flow regulation at the Armando Ribeiro Gonçalves reservoir (ARG), located in the Brazilian semi-arid region, through the integrated application of hydrological modeling and water balance analysis. The SMAP hydrological model was selected for this modeling effort, calibrated and validated using observational data from two gauging stations: a conventional one and another located immediately upstream of the ARG reservoir. The latter proved to be more representative of the upstream hydrological conditions, highlighting the importance of considering the influence of anthropogenic interventions and regional specificities when selecting stations for calibration. The SMAP was forced with climate projections from the MIROC6 model under the recent/historical climate scenario (1990–2019). The results indicated that, although the MIROC6 model adequately reproduces the seasonality of climatic variables, it tends to overestimate precipitation and underestimate evapotranspiration, which, without corrections, leads to an overestimation of simulated flows. The application of a bias correction method is expected to mitigate these discrepancies, allowing for a better adjustment of climate data to the hydrological model and, subsequently, to the water balance modeling. This will enable the projection of regulated flows under the SSP2-4.5 and SSP5-8.5 scenarios for the period 2023–2042. The proposed methodology provides a solid foundation for evaluating future scenarios of water availability in hydrological systems and for guiding the integrated management of water resources in the Piancó-Piranhas-Açu river basin.