Analysis of hydrological impacts caused by climatic and anthropogenic changes in Upper Grande River Basin, Brazil

Abstract

This study quantified hydrological impacts caused by climate and anthropogenic changes in nine basins in the Upper Grande River Basin (URGB) region and estimated potential future impacts on runoff based on climate model projections. The Budyko framework was used as a conceptual approach to estimate the causes of runoff variation by the decomposition method. Assuming that land use will not change in future, the runoff was estimated for 2006–2040, 2041–2070, and 2071–2099 time-slices using regionalized projections from four different climate models. The decomposition method indicated a strong influence of both climate and land-use changes in the hydrological regime in the URGB, with the expansion of the agricultural areas being the most important driver of anthropogenic impacts. Future climate projection multi-model ensembles indicated a reduction in average runoff. The Budyko framework performance on future projections presented similar trends to hydrological modeling estimations from previous studies in the same region, indicating the suitability of the method as an additional tool for assessing future climate change impacts on water availability.