Hydrologic response to large-scale land use and cover changes in the Upper Paraná River Basin between 1985 and 2015

The Upper Paraná River Basin (UPRB) has undergone remarkable land use and cover changes (LUCC) in recent decades. This paper analyses the hydrologic response to LUCC in the UPRB between 1985 and 2015, using the Soil and Water Assessment Tool (SWAT) model. The impacts of LUCC were examined for annual, wet, and dry season (both during calibrated and validated periods) between 1984 and 2015. The most substantial LUCC were the extensive reduction of the cerrado and the expansion of agriculture areas. The simulations demonstrated that the LUCC caused important changes in basin hydrology. For instance, an increase (decrease) of surface runoff in the wet (dry) season at most UPRB subbasins was observed. In addition, the simulation results revealed a reduction in actual evapotranspiration and an increase in soil moisture in the annual and wet season. Consequently, most of the major rivers of the basin presented an increase (decrease) in their discharge in the wet (dry) period. The major changes in the hydrologic components were observed in the central-western and southern parts of the UPRB. At the river mouth of the UPRB, the LUCC led to an increase in long-term mean discharge values of 4.2% and 1.1% in the annual and wet season and a decrease of about 2.2% in the dry period. This study provides a large-scale modeling and valuable information that could be used to improve planning and sustainable management of future water resources within the basin