Elaborating rating curves for implementation of the MGB hydrological model in a river basin, Amazon region, Brazil

The main objective of this study was to implement and execute the MGB hydrological model for the Itacaiúnas River basin (IRB) using flow data calculated using rating curves from 8 streamflow gauges. To evaluate the performance of the model, the Nash–Sutcliffe coefficient of daily flows (NSE), Nash–Sutcliffe coefficient of daily flow logarithms (NSELog), relative long-term error (BIAS%) and correlation coefficient ( r ) between flows were used. The results showed that the model better simulated the minimum flows and the periods of recession but did not reach the peak flows at some stations, which might have been related to the extrapolation of the rating curves. In addition, the flow duration curves had a good adjustment in the low flows. Finally, limitations of the model and monitoring were observed, in addition to regional characteristics that may have interfered with the performance of some points. In general, it was concluded that the results were very promising and satisfactory. Thus, the MGB hydrological model managed to reproduce the basin’s seasonality and can be used as a tool to support the management of water resources in the basin.