Estudos hidro-climatológicos da bacia do Rio Curuá–Una: aplicação do modelo de grandes bacias (MGB–IPH)

Abstract

The Hydraulic Concepts Model Distributed from Large Basins of the Hydraulic Research Institute (MGB-IPH) is a rainfall-type model validated in several basins in South America, including several rivers in the Amazon Basin. The inputs of the model are climatological, pluviometric, relief and soil cover data. This study intends to test the sensitivity of the model in extreme scenarios of soil use and occupation, changes in precipitation and mean air temperature; Characterize aspects related to geohydrology, morphology and morphometry of the Curuá-Una river basin, located to the southeast of Santarém-Pará, concomitantly, to evaluate the influence of changes in land use and occupation occurring in the basin between 1985 and 2015 in the regime Water. In preprocessing the software was used MapWindow-GIS and plug-in IPH-Hydro Tools, and in the MGB-IPH plugin processing. In the sensitivity test of soil use and occupation the results showed that low vegetation and anthropization increase the maximum peaks of flow; In periods of low Amazon rainfall, the low vegetation scenario has a higher flow rate and the medium and high vegetation scenario prevents intense flooding. In the tests of changes in the precipitation regime, a reduction of 50% of rainfall reduced the flow by 32%, and the increase of 50% of rainfall increased the flow by 218.6%. However, in the tests of increase of the mean air temperature the results did not show significant responses in the flow regime, however, this scenario, added with the increase and/or decrease of the precipitation regime, was presented as attenuator for both floods and droughts. The characterization of the Curuá-Una basin allowed the generation of base data capable of describing the hydrological behavior of the region and important metric data for space demarcation in decision-making, and the estimated drainage area design had a value of 17, 351.34 Km2 and maximum width = 125.78 km; The classifications of land use and occupation showed that the middle and high vegetation class suffered a reduction of 10.76%, and the anthropogenic and soil class increased by 8.52% between 1985 and 2015; The type of yellow latosol soil covers an area of 833.64 km2. The results for the evaluation of the influence of changes in land use and occupation between 1985 and 2015 in the water regime showed that the influence is not significant in the basin scale.