Evaluation of climate change scenarios in water resources planning of rio de janeiro metropolitan region and paraíba do sul lower course water systems

Abstract

This study aims to analyze the water system embracing the Metropolitan Region of Rio de Janeiro and the Lower Paraíba do Sul river Region, which acquired deeper importance since the 2014-2015 water crisis. Such calamity highlighted the multifaceted issue of transposing water from the Paraíba do Sul river to the Guandu river during drought periods. In addition, the study aims to incorporate exploratory analysis of climate projection scenarios into long-term water resources planning. The study proposes the analysis of flows from climate projection scenarios of the hydrological model MHD-INPE (Distributed Hydrological Model -National Space Research Institute). Such model was entered with simulated data from regional and global atmospheric models, for three stations located in the Paraíba do Sul river basin: Santa Cecília, Sobragi and Simplício. Demands for human supply and economic activities in the transposition to the Guandu river and the low course of the Paraíba do Sul river were estimated. The relationship between supply projections and water demand was assessed in order to identify the system vulnerability. The climate change scenarios analyzed in this study indicate that the system, both in the Metropolitan Region of Rio de Janeiro and in the Lower Paraíba do Sul, presents a possibility of deficit, especially in situations of scarcity, which means, when the minimum flows are analyzed. The analysis of future water supply projection scenarios is concluded to be fundamental for enabling policy-makers to incorporate proposals that address main system uncertainties and potential climate change impacts.