Resumo. The new Forest Code (NCF) which substitutes the Law No. 4.771, Old Forestry Code (ACF), regulates the definition of Permanent Preservation Areas (APP’s) of waterway marginal ranges, considering that currently their delimitation must be done from the edge of the regular bed rail (LR), differently from the ACF, which indicated the APP range beginning from the larger hydrological river bed (LMH). The objective was to compare the application of the NCF in river ciliary range, opposite to the Old Code, as well as the difference between themselves, in a typically rural basin. The Arroio Grande study case was used, the extent of the LR was defined, as well as of LMH and its respective APP range, thus, forming the Permanent Protection Range (FPP). Within each protection strip, it was utilized the land use analysis and also its commonest difficulties that define the boundaries of the APP defining bed. Through the maps which were obtained, the APP of the Arroio Grande must be 50m from the LR rail, which is bounded through this river, and includes river shores and islands. The NCF brings as a contribution to permit the owners the adequacy of degraded areas using a minor range of preservation and facilitating the definition of LR by satellite images. Thus, one can compare the laws through the maps and conclude that the NCF has brought some progress such as the ease of in the demarcation of APP, but it is milder compared to the size of the protected area.