DELIMITAÇÃO DE ÁREA DE PRESERVAÇÃO PERMANENTE EM TOPO DE MORRO NA BACIA HIDROGRÁFICA DO RIO JAMARI

Abstract

Permanent Preservation Areas (APPs) on hilltops regulate runoff and reduce erosion, which are essential for the environmental sustainability of river basins. However, the presence of human activities in some APP areas points to challenges in the full protection of these spaces. Brazilian environmental legislation seeks to balance environmental protection requirements with the country's socioeconomic development, particularly pressures from the agricultural sector, which have raised questions about the effectiveness of legal enforcement in sensitive areas, such as river basins. In this regard, we sought to analyze the compliance between hilltop APPs and the forest vegetation still present in these areas, in accordance with the Brazilian Forest Code, in the Jamari River Basin (BHRJ). The methodology involved the acquisition of satellite images and the processing of Digital Elevation Models (DEM) to generate slope and hypsometry maps and to delimit the hilltop APPs using the free software QGIS, combined with the GRASS, SAGA and GDAL resources. The analysis of the hilltops revealed altitudes ranging from 100 to 566 meters and slopes reaching up to 89. The total area delimited as hilltop APP was 693.0 km², of which 433.42 km² (62.54%) still have forest vegetation, 29.11% are composed of pastures, while the remainder (8.34%) is represented by the classes of non-forest natural formation, non-vegetated areas, water bodies and agriculture. The distribution of APPs showed that the largest concentration is located in the southern portion of the basin.