Effects of sugarcane expansion on runoff and evapotranspiration in the Rio Grande basin, Brazil / Effekter av sockerrörsplantagers utbredning på avrinning och avdunstning i Rio Grandes avrinningsområde i Brasilien
The demand for biofuel has increased in recent years as more countries desire to reduce their dependence on fossil fuels. Therefore, the amount of sugarcane plantations has rapidly increased in Brazil, one of the largest producers of ethanol from sugarcane in the world. This increase raises concerns of what effects this replacement of native vegetation and traditional crops to sugarcane plantations may have on local hydrology and climate. In order to fill up this gap, this study aims to evaluate the effects of sugarcane expansion on surface runoff and evapotranspiration in the Rio Grande basin, Brazil. For the numerical experiments carried out in this study, scenarios of sugarcane were generated based on topographic features and mapping of suitable areas for sugarcane plantation made by the Brazilian Institute for Agricultural Research (EMBRAPA). These land use scenarios were provided as input to a distributed hydrological model, which estimated surface runoff and evapotranspiration rates for the river basin. Results from simulations showed that sugarcane expansion implied to a reduction of up to 10.8 % of surface runoff and an increase of evapotranspiration rate by 9.0 %.