Modelagem do regime hidrológico das bacias do Rio Piracicaba e do Alto Rio São Francisco no clima futuro

Abstract

Quantifying the change in the hydrological regime and its vulnerability play a crucial role in defining and implementing sustainable management for water in a changing environment. Associated with the growing discrepancy between supply and demand of water resources, it is essential to know the changes in the flow regime modified by climate change. Thus, the objective of this study was to evaluate the effect of climate change on the flow regime of the Piracicaba river basin and Alto São Francisco river basin. For this, part of the uncertainties of hydroclimatic projections was considered, from hydrological simulations using two hydrological models, the SMAP (Soil Moisture Accounting Procedure) and the HYMOD (Conceptual Hydrological Model). These models were forced with regionalized climate data (~25 km) from the MIROC and CANESM models, which integrate Global Circulation Models of the Coupled Model Intercomparison Project Phase 5 (CMIP5), for two greenhouse gas emission scenarios (RCP). 4.5 and RCP 8.5) in the near future (2021-2046). Projections for the flow regime of both river basins in the future climate indicate, with a lower degree of uncertainty, a considerable increase in the long-term average flows, followed by an increase in the extreme maximum flows. Such a future hydroclimatic framework indicates the need for greater attention to the safety of the reservoirs in those basins, as well as actions to contain possible floods. Regarding water availability, for the Alto São Francisco River basin, the minimum flow (Q95%) followed the trend of increasing projections of the long-term average flow and maximum flows. For other hand, this projection was not confirmed in total for the Piracicaba river basin, where the projection of the minimum flow (Q95%) may be lower than the average minimum flow observed in recent climate.