Metodologia para estimativa de vazões impactadas pelas mudanças climáticas em uma bacia hidrográfica de usos múltiplos

Abstract

Climate change is a reflection of changing one or more of its representative variables. Precipitation and evaporation are some of these variables and are also the input data from the flow prediction models, which is the primary information for managing a watershed. In this context, the present work aims to develop a methodology for forecasting the monthly average flow in a multi-purpose watershed, influenced by climate change. The specific study site was the Ribeirão do Cipó River Basin, Poços de Caldas-MG. Precipitation and evapotranspiration data designed by the Eta-CPTEC Regional Climate Model (RCM) nested with the Global Climate Models (GCM's): CanESM2, HadGEM2-ES and MIROC5 were used. Projections were made in scenarios RCP 4.5 and 8.5, both for the periods 2010-2039, 2040-2069 and 2070-2099. These data fed the rain-flow hydrological model called SMAP, which after calibrated, generated the flow projections. The methodology presented results similar to the methods used as reference. The main aspects are the high resolution of climate variable forecasts (5 km and 20 km wide grids) and the good response of the methodology for a small basin. As all climate modeling brings uncertainties, the need to calibrate the SMAP model with data from another watershed due to the lack of data proved to be the main limitation of the method. However, precisely for locations with low data availability, a recurring situation in the Brazilian reality when it comes to smaller basins, the methodology presents itself as a good alternative in obtaining initial flow estimates, helping in the management of water resources.