Modeling the effects of climate change on streamflow and water quality of watersheds in the state of São Paulo

Climate change and its effects on water resources have been discussed by many researchers and public authorities. These effects will manifest in a very long time scale, affecting the streamflow and water quality for the population. Such effects can be predicted using hydrological models and global climate models (GCM) that provide estimates about climate in the future, based on climate scenarios. This study aims to evaluate the effects of climate changes on the streamflow and water quality and to zoning the hydrological response of watersheds in the state of São Paulo. A regional mapping of the watershed response was generated and critical areas were identified for the stability of water production in the watersheds. Some watersheds will be negatively impacted by the climate, presenting a reduction of the streamflow, and other watersheds will be less affected by the climate, because their physical characteristics constitute a more relevant factor to the water yield. Therefore, it is necessary to give importance to the watersheds of the State of São Paulo due to the urban and industrial concentration in that region. The results provide subsidies to guide public policy and propose ways to manage the land use in watersheds. (AU)