Delimitação de áreas potenciais de recarga de aquíferos, no município de São Sepé-RS

Abstract

The work "Delimitation of Potential Aquifer Recharge Areas in the Municipality of São Sepé-RS" aimed to identify and map priority regions for water recharge, contributing to the sustainable management of groundwater resources. The research is justified by the importance of groundwater in public supply and agricultural activities, especially in a region that faces frequent droughts and suffers from improper land use. The adopted methodology combined Remote Sensing (RS) and Geographic Information Systems (GIS) techniques, integrated with the Analytic Hierarchy Process (AHP) method, which enabled the analysis and prioritization of essential environmental variables for water recharge, such as slope, soil types, land use and occupation, rainfall, and drainage network. From this information, thematic maps were generated, allowing the identification of areas most favorable to water infiltration and, consequently, aquifer recharge. The results revealed that areas with high and very high recharge potential are concentrated in the northwest, south, and central regions of the municipality. These areas have more permeable soils, low drainage density, and gentle relief, which favor the infiltration process. In contrast, areas classified with moderate to low potential are predominantly located in the eastern part of the municipality, where less permeable soils, steeper slopes, and intensive land use limit recharge and increase surface runoff. The average annual precipitation in the region ranges between 1650 and 1750 mm, reinforcing the importance of rainfall in the recharge process. However, the effectiveness of this recharge directly depends on the soil's retention capacity and the topographic conditions of each area. The comparative analysis between the recharge maps and the hydrogeological domains indicated that sedimentary formations have a greater infiltration capacity, while areas formed by crystalline rocks have natural limitations due to lower permeability. In the final considerations, the study highlights the need to preserve recharge areas as a fundamental strategy to ensure the maintenance of groundwater quantity and quality. The results provide technical support for the formulation of public policies focused on soil conservation and management, in addition to serving as a basis for future research in water resource management. The applied methodology, which integrated the AHP method and geoprocessing, proved to be effective and replicable, allowing its adaptation to other regions with similar characteristics. The work reinforces the relevance of integrating environmental variables and the use of technologies for water resource management, significantly contributing to water security and the sustainable development of the municipality of São Sepé and its surroundings.