Evaluation of meteorological and hydrological droughts in the juturnaíba dam drainage basin, Rio de Janeiro state, Brazil

Abstract

The study aimed to classify the climate and investigate possible meteorological and hydrological droughts in the drainage basin of the Juturnaíba dam, whose reservoir has the largest water volume in the state of Rio de Janeiro to meet a demand of 630,000 people. Rainfall stations located in the basin were considered and the results allowed to classify the climate as mesothermal, ranging from super humid to humid, with little or no water deficit. Regarding the drought quantifier indices, the results did not identify extremes. The extreme weather indicators suggest that rainfall is occurring in a concentrated manner with increasing numbers of consecutive dry days. Finally, a hydrological drought was identified between August and November 2014, resulting in a drawdown of 0.41 m. However, without evidence of drought, in October 2007, the reservoir suffered a reduction of 0.94 m in its level, the largest in the historical data. The study concludes the necessity to investigate the reasons for this depletion and the resumption of the hydrological monitoring.