Assessment of climate change impacts on streamflow and hydropower potential in the headwater region of the Grande river basin, Southeastern Brazil

Abstract

Maintaining water availability and electric energy production are the major concerns for the future in countries which are extremely dependent on their water resources like Brazil. The objective of this study was to assess the impacts of climate change on streamflow and therefore on hydropower potential of the Grande river basin headwater region, Southeast Brazil. For this purpose, the SWAT model was used to simulate the hydrological behaviour of the headwaters under the Representative Concentration Pathways 4.5 and 8.5 scenarios, obtained from the Regional Climate Models Eta-HadGEM-ES and Eta-MIROC5 between the years 2007 and 2099. Through power duration curves we estimated the hypothetical average annual energy production at three hydropower plants installed in cascade in the region, being, from upstream to downstream, Camargos, Itutinga and Funil. These plants account for a potential of 277 MW. SWAT was able to simulate the streamflow of the Grande river basin headwaters and, therefore, to reproduce the observed monthly streamflow from the baseline period reasonably well for all three hydropower plants. In general, the results indicated a significant streamflow reduction and therefore reductions in runoff during all the simulated periods and all radiative forcing analysed, when compared to the baseline period. Thus, these results led to reductions in hydropower potential and hence decreases of the annual energy production varying from 6.1 to 58.6% throughout the 21st Century.

Climate change impacts under representative concentration pathway scenarios on streamflow and droughts of basins in the Brazilian Cerrado biome

“…According to Oliveira et al . (), the hydropower potential is calculated as a linear function of streamflow. Therefore, percentage changes between the future periods in comparison against the baseline in hydropower potential are the same as in streamflow.…”

“…In general, our results indicated a strong decrease in the annual runoff in future, mainly at the end of the 21st century, which may significantly alter the water availability in the three basins in the Cerrado Region. According to Oliveira et al (2017), the hydropower potential is calculated as a linear function of streamflow. Therefore, percentage changes between the future periods in comparison against the baseline in hydropower potential are the same as in streamflow.…”

“…These predictions aim at supporting future adaptation at different environmental conditions (Poff et al ., ). In this way, the Soil and Water Assessment Tool (SWAT) has been widely applied in the assessment of the impacts of climate change on the hydrological regime of basins under future different greenhouse gas emission scenarios (Devkota and Gyawali, ; Kumar et al ., ; Oliveira et al ., ; Tan et al ., ). Cousino et al .…”

“…These predictions aim at supporting future adaptation at different environmental conditions (Poff et al, 2016). In this way, the Soil and Water Assessment Tool (SWAT) has been widely applied in the assessment of the impacts of climate change on the hydrological regime of basins under future different greenhouse gas emission scenarios (Devkota and Gyawali, 2015;Kumar et al, 2017;Oliveira et al, 2017;Tan et al, 2017). Cousino et al (2015) evaluated the effect of climate change on runoff and water quality using the SWAT model driven by four GCMs under the four representative concentration pathway (RCPs) scenarios in Maumee River watershed in the United States.…”

“…Zhang et al (2016) assessed the impacts of climate change on the streamflow of the Xin River basin, China, considering three GCMs under three RCPs scenarios with SWAT model. Oliveira et al (2017) used simulations from the downscaling of the HadGEM-ES and MIROC5 under the RCP4.5 and RCP8.5 scenarios by the Eta model (Chou et al, 2014b) coupled with the SWAT model to assess the climate change impacts on streamflow and hydropower potential of the Upper Grande River basin, southeast Brazil. Saharia and Sarma (2018) analysed the effect of future climate on hydrologic processes in the Bharalu and Basistha basins, India, using the projections from GFDL-ESM2M RCP2.6 and RCP8.5 scenarios in combination with the SWAT model.…”