Avaliação das áreas potenciais para preservação ambiental e áreas de conflito na bacia hidrográfica do ribeirão São Lourenço Ituiutaba/MG

Abstract

The Permanent Preservation Areas (PPAs) help in the conservation of water resources, soil and water bodies protection, as they allow greater water percolation into the soil, offer protection against erosion, lixiviation and prevent that excessive amounts of sediment, or fertilizer residues, waterways' eutrophication. The planning of land s use and cover ensures the development of sustainable activities necessary to the system s balance which makes up the watershed, helping in the maintenance of water s quantity and quality. This study aimed evaluate the conflict areas of land use in PPAs, as well as identify areas with preservation potential at Ribeirão São Lourenço s watershed and with that generate a map of potential areas for preservation. Therefore, it was accomplished the mapping of land use and cover and elaborated thematic maps of land use, soils, declivity, hypsometry, capacity of use, PPA and areas for preservation. It was used a specific methodology to evaluate the land use capacity checking unsuitable areas for agriculture which would have potential for environmental preservation. Furthermore, from the crossing data, It was diagnosed conflicts such as current use in PPA areas. Of 29,429.10 ha of the watershed, 12.64% correspond to the PPAs. Of this amount, 34.84% present conflicts of use represented by human activities in PPA and 65.16% are occupied by native vegetation. Although a great part of the PPAs are covered by native vegetation, it is necessary the use adequacy in conflict areas for the environmental regularization and conservation of natural resources and ecosystems. Of the watershed total area, 88.82% are apt for agriculture and belong to classes of use capacity II and III. However, some conservation techniques must be accomplished to prevent the deterioration of the land. Despite being apt for agriculture, it must be noted in these classes the existence of permanent preservation areas. In class IV which corresponds to 2.11%, the agricultural use is more restricted due to more severe limitations, therefore it is indicated for perennial crop. The inapt areas for agriculture represent 6.27% of the watershed area. These places show a high-risk of erosion or poor soil drainage, so they were placed in the classes of capacity of use VII and VIII. The GIS techniques used in this study allowed efficiently data obtaining reffering to potential environmental preservation areas, besides the main conflicts in PPAs in the area. These results can help in the planning and management of territory occupation of the watershed, and minimizing the impacts of anthropic use in it.