Modelagem hidrológica na bacia do rio Capim – estado do Pará.

Abstract

The model Soil and Water Assessment Tool (SWAT) is used in order to estimate the hydrological cycle components of the Capim River basin, which is located in Brazilian states of Pará and Maranhão, from January 2000 up to December 2010. Data from an automatic meteorological station located at Paragominas city have been used, in addition to rainfall and stream flow data provided by the National Water Agency (ANA). The climate in the study area has well defined seasonality with rainy periods from January to May and dry periods from June to December. In general, the results of the SWAT model were satisfactory when compared with other studies ones regarding Brazilian river basins. Interestingly, this study is a pioneer in the application of the SWAT model for research of watersheds in Pará state. Given the importance of this basin’s water resources, this work can certainly contribute to a better management and planning of the environmental resources provided by the Capim River basin. Monthly flow data of the Capim River were used to validate the model SWAT, which has resulted in values of the coefficient of efficiency (COE) which ranged between 0.59 to 0 .65 (for the sub-basins 3 and 5) and 0.87 for the whole investigated period (2000-2010). It was also observed that , in percentage terms, the Capim River monthly runoff simulated by the SWAT model, after some adjustments, presented a reduction in its estimation error, which started from an overestimation of 210.75% until to reach an underestimation of 26% (in the sub-basin 3), and 219.18% to 18% (in the sub-basin 5), respectively. Overall, it was possible to spatialize the components of the Capim River basin hydrological cycle and to validate the model, what may be useful in further studies concerning this hydrological basin.