Impact of climate change on groundwater recharge in a Brazilian Savannah watershed

Abstract

There is little information about the availability of water in the Cerrado biome, the main agricultural frontier in Brazil, especially about groundwater, and this has compromised the region’s economic and social development, as well as environmental sustainability. The reduction of rainfall in this region, indicated by numerous climate models, may reduce aquifer recharge and, consequently, groundwater availability and sustainable development of the Cerrado biome. This study aimed to evaluate the impact of global climate change on groundwater recharge in a Brazilian Savannah watershed. Rainfall and water table depth data were recorded between 2007 and 2015. Based on these data, equations were developed relating the average monthly depth of the water table with the accumulated average monthly rainfall. From these equations, monthly average recharges considering the future climate estimates made by climate models (Eta-HadGEM2-ES and Eta-MIROC5) and Representative Concentration Pathway (RCP) scenarios (4.5 and 8.5) were calculated. In a pessimistic scenario (RCP 8.5), the average monthly groundwater recharge is decreasing in the beginning and in the end of the rainy season, indicating that there may be an increase in the dry season and, consequently, a reduction in water availability in the Cerrado biome region.