The impact of land use and land cover changes on surface and baseflow dynamics in a Brazilian savanna basin: a case study of the Corrente River Basin

The Cerrado biome, known as the Brazilian Savanna, plays a critical role in sustaining major Brazilian aquifers and river basins; however, it has undergone substantial land use and land cover changes driven mainly by agricultural expansion, particularly in western Bahia. This study assesses the impacts of land use and land cover changes on surface and baseflow dynamics in the Corrente River Basin, an important tributary of the São Francisco River. Precipitation, streamflow (surface runoff and baseflow), and land use data from 1985 to 2023 were evaluated using open-access dataset and statistical methods. Results indicate a decreasing trend in precipitation and streamflow, although only the reduction in streamflow was statistically significant. Baseflow represented approximately 93.75% of total streamflow but exhibited a significant decline over the study period, accompanied by a reduction in surface runoff. A statistically significant change point was identified in 2007, marking an abrupt decrease in both total streamflow and baseflow. Correlation analysis revealed a strong positive relationship between baseflow and native vegetation cover (correlation coefficients of 0.885 for Forest cover, and 0.870 for Herbaceous and Shrubby Vegetation), whereas anthropogenic land uses, such as temporary crops (-0.884) and non-vegetated areas (-0.806), showed negative correlations. Between 1985 and 2023, temporary crop areas increased by 3523%, while forest formations and herbaceous vegetation declined substantially. These findings demonstrate that intensification on water demand due to agricultural, has significantly altered hydrological processes in the basin, highlighting the importance of integrated and sustainable water resource management strategies in the Brazilian Savanna.