Impacts of Land Use Change and Climate Variability on Streamflow in the Piracicaba Basin, Brazil

Abstract

Abstract Climate variability and land use change are two conditioning that affect hydrological processes in watersheds. Based on these findings, it is necessary to understand the processes involved in climate and land use and its impact on water systems. In this context, this study aimed to simulate climate scenarios combined with the change of land use and to analyze the impacts on streamflow in the Piracicaba basin with the SWAT model. Two periods were selected based on the preliminary result of detection of the abrupt change point of the annual streamflow series, using Petitt’s non-parameter test. The first period selected prior to the occurrence of the point of change ranged from 1985 to 2000. The other period after the point of change ranged from 2001 to 2015. Land use maps of the years 1990 and 2010 were used to represent the two periods. The results showed a good performance of the SWAT model. The NS (Nash-Sutcliffe coefficient) was 0.88 in calibration for both periods. In the validation, the NS was 0.92 and 0.94 for the first and second periods respectively. Then, we simulate climate and land use scenarios and compare them to the current scenario (baseline). The simulation results showed that the streamflow in the Piracicaba basin in the period 1985–2015, had more intense responses to land use change than climate variability.