This paper fits within the CAD program (Contaminants, Siltation and Dredging in the estuary of Paranaguá/PR) purposing the application of GIS (Geographic Information System) in delimitation of Mandatory Preservation Areas (APP's) in the hydrographic basin of Sagrado River (Morretes/PR). As a preliminary stage, it was effectuated the study of the current Brazilian legislation (Forest Code and CONAMA resolutions) concerning to the delimitation of Mandatory Preservation Areas (APP's). Then, using the software ArcGis 9.2, it was delimitated the following classes of APP: 1) water spring, 2) riparian forest, 3) around tanks, 4) top of hills 5) top of mountains, 6) ridge lines, 7) slopes above 45 degrees and 8) mangroves. The application of GIS proved to be an efficient tool for the Mandatory Preservation Areas' delimitation, from the results it was verified the existence of two APP's groups: the first one represented by the set of categories 1, 2, 3 and 8 with 51,9% of the whole mapping, and a second group witch is represented by the set of categories 4, 5, 6 and 7, with 48,1% total of the basin's APP's. The riparian forest APP has the biggest representation, with 28,9km² having as the main environmental functionality the preservation of water resources.
Sagrado drainage basin; Mandatory Preservation Areas; Geographic Information System
