Effects of climate and land cover changes on water availability in a Brazilian Cerrado basin

Abstract

The effects of riparian restoration and soil and water conservation practices on catchment hydrology are still unclear. Here, we assess whether a positive change in soil and water conservation practices and riparian reforestation will affect the water availability and boost resilience in a Brazilian Cerrado basin under climate change scenarios. This study was developed in the Três Marias basin (50.600 km²) located in southeastern Brazil. First, we calibrated (1992–2005) and evaluated (2006–2012) the Soil and Water Assessment Tool (SWAT) model. Then, we created a land cover and land use change (LCLUC) scenario that considers improving soil and water conservation practices and the reforestation of riparian zones, following the recommendations of the Brazilian Payment for Ecosystem Services (PES). We also used the trend SSP2-4.5 and the fossil-based economy SSP5-8.5 (Shared Socioeconomic Pathways) climate scenarios data from the Coupled Model Intercomparison Project Phase 6 (CMIP6) project for the period of 2015–2100. Along with a decrease of 5 %–15 % in precipitation in the projected period, an increase of 7 %–15 % in forest areas due to the LCLUC scenarios generated an increase in evapotranspiration values up to 38 %, resulting in a decrease of surface runoff and baseflow. Riparian reforestation and soil and water conservation practices did not necessarily enhance water availability on the simulations performed, as expected by many PES.