The HAND (Height Above the Nearest Drainage), a quantitative topographic descriptor, is used to classify terrain in a manner that is related to local soil water conditions, providing hydrological meaning to the SRTM DEM. In this paper, we compare performance of using the HAND grid instead of the SRTM DEM for classifying, at regional scale (19 000 000 km2), drainage conditions of terra firme environment (plateau, slope, ecotone and waterlogged) in the Eastern Amazon, Brazil. Additionally, we emphasize the need to attenuate the canopy effects of the SRTM DEM for the boundary between forested and deforested areas, in order to produce coherent data for hydrological modeling.