Over the years, there has been a decline in renewable natural resources, including water. Therefore, it is necessary to control such use, promoting the management, protection and management of water bodies, in face of their multiple uses. The study area is the catchment area of the Santa Cruz do Apodi-RN dam, located in the Potiguar Meso-region of the state of Rio Grande do Norte, involving most of the municipalities of the Alto Oeste Potiguar. This work has as objective the automatic delimitation of the basin, from a Digital Elevation Model (MDE), of the TOPODATA project, obtained from the Institute of Space Research (INPE) and using the free GIS and open language QGIS with the help of the SAGA, GRASS and TauDEM plugins, evaluating their performance. After the delimitation, perform the morphometric characterization of the basin, based on the calculation of some physical parameters. Concluding that the plugin that obtained better performance was the TauDEM, performing the delimitation and tracing the drainage network, in a satisfactory way. It is worth pointing out that the others also attended to what was requested. In relation to the morphometry of the basin, it can be observed that it presents a good drainage area, with little tendency to great floods, presenting an elongated shape and a well distributed drainage network along the area of the basin.