Articles | Volume 20, issue 11
Hydrol. Earth Syst. Sci., 20, 4673–4688, 2016
Hydrol. Earth Syst. Sci., 20, 4673–4688, 2016

Research article 24 Nov 2016

Research article | 24 Nov 2016

Reservoir storage and hydrologic responses to droughts in the Paraná River basin, south-eastern Brazil

Davi de C. D. Melo1,2, Bridget R. Scanlon2, Zizhan Zhang2, Edson Wendland1, and Lei Yin3 Davi de C. D. Melo et al.
  • 1Department of Hydraulic and Sanitary Engineering, University of São Paulo, Avenida Trabalhador São-carlense, 400, Parque Arnold Schimidt, São Carlos, SP, 13566-590, Brazil
  • 2Bureau of Economic Geology, University of Texas at Austin, 10100 Burnet Rd, Austin, TX 78758, USA
  • 3Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, 23 San Jacinto Blvd & E 23rd St, Austin, TX 78712, USA

Abstract. Droughts are particularly critical for Brazil because of impacts on water supply and because most (70 %) of its electricity is derived from hydroelectric generation. The Paraná basin (PB), a major hydroelectric producing region with 32 % (60 million people) of Brazil's population, recently experienced the most severe drought since the 1960s, compromising the water supply for 11 million people in São Paulo. The objective of this study is to quantify linkages between meteorological and hydrological droughts based on remote sensing, modelling, and monitoring data using the Paraná River basin in south-eastern Brazil as a case study. Two major meteorological droughts were identified in the early 2000s and 2014, with precipitation 20–50 % below the long-term mean. Total water storage change estimated from the Gravity Recovery and Climate Experiment (GRACE) satellites declined by 150 km3 between April 2011 and April 2015. Simulated soil moisture storage declined during the droughts, resulting in decreased runoff into reservoirs. As a result, reservoir storage decreased by 30 % relative to the system's maximum capacity, with negative trends ranging from 17 (May 1997–April 2001) to 25 km3 yr−1 (May 2011–April 2015). Storage in upstream reservoirs is mostly controlled by natural climate forcing, whereas storage in downstream reservoirs also reflects dam operations. This study emphasizes the importance of integrating remote sensing, modelling, and monitoring data to evaluate droughts and to establish a preliminary understanding of the linkages between a meteorological and hydrological drought for future management.

Short summary
Drought propagation from rainfall deficits to reservoir depletion was studied based on remote sensing, monitoring and modelling data. Regional droughts were shown by widespread depletion in total water storage that reduced soil moisture storage and runoff, greatly reducing reservoir storage. The multidisciplinary approach to drought assessment shows the linkages between meteorological and hydrological droughts that are essential for managing water resources subjected to climate extremes.