Résumé
The watershed of Lago Grande do Curuai is a floodplain region subject to the floods of the Amazon River, located in the state of Pará, near the cities of Óbidos and Santarém. For the purpose to understand the space-time dynamics of the land use and coverage of the region, images of orbital sensors from the Landsat 5 and 7 satellites were classified for the years 1985, 1997 and 2014. Classes of use and coverage were determined: forest mainland, secondary vegetation (capoeira), pasture, " roça " , urban area, natural field (savanna), floodplain forest, natural pasture and hydrography. Information collected in three field studies, performed at different times (full and dry), was used to validate the classification, using Kappa index. The result of the classification shows a certain stability of the classes of use coverage in the basin. In the 30 years of analysis, there is a decrease in the areas of forest mainland, and the class in which there is greater increment is the one of secondary vegetation / capoeira, with the grasses and " roças " being stable. The flood and dry dynamics of the basin allows the use of the lowland for pasture and agricultural cultivation, reducing the need to open new areas on mainland, which would lead to the suppression of forest.