Mapeamento de áreas de preservação permanente dos mananciais com fins de abastecimento público de Alagoas

Abstract

Natural environments are sources of ecosystem goods and services essential to life, and are becoming increasingly degraded due to environmental impacts. Aiming at the conservation of these areas, the Brazilian Forest Code (Law nº 12.651/2012) establishes and defines Permanent Preservation Areas (APPs) with the purpose of protecting water resources, guaranteeing the protection of marginal strips of water courses and areas in the around lakes, springs and reservoirs, biodiversity, ensuring the well-being of human populations, among others. However, the absence of correct mapping of the areas to be protected makes inspection difficult and compromises their conservation. In this sense, the use of geoprocessing through satellite images has been recognized as an important tool. The objective of this study was to identify and map the Permanent Preservation Areas of surface water sources for public supply in the State of Alagoas. The method consisted of four main steps: i) identification of surface water sources through the geographic coordinates and hydrography of Alagoas (shape); ii) manual delimitation of artificial reservoirs and rivers/streams; iii) application of distance limits (buffers), with distances between 15 and 200 meters; iv) production of maps with the delimitation of protection areas. The QGIS software was used to produce the maps. Of the 67 springs identified by geographic coordinates, 42 had their Permanent Preservation Area mapped, with 6 springs, 6 artificial reservoirs, 18 rivers/streams and 12 points on the São Francisco River. The other surface springs were not mapped due to limiting conditions. It was noted that there are varying degrees of protection, with regions completely protected by native vegetation or not, others partially and/or with no vegetation in their APP, with overlapping urban areas or soils used for agriculture and pasture. These springs are located in regions with diversified environmental characteristics. Therefore, it is recommended that APPs that are in accordance with the Forest Code (2012) remain protected and those that are overlapped by urban areas or for agricultural activity, need inspection actions by the competent state and municipal bodies, in order to mitigate impacts on water.