Resumo:
The identification of recharge areas is not so simple to obtain, factors such as rainfall intensity and duration, evapotranspiration, surface runoff, soil use and occupation, aquifer and soil properties, present variations over time. In addition, given the uncertainties of the method used and the variations in the importance of each criterion by the decision maker, they may cause different results. However, it is important to point out that given the need to integrate several variables, the use of remote sensing and the application of geoprocessing techniques from the use of a Geographic Information System (GIS) become increasingly essential in decision making. The underground water recharge areas are responsible for the maintenance, quality and quantity of water that reaches the aquifers through the infiltration process. The objective of this study was to identify probable areas of underground water recharge in the municipality of João Monlevade-MG, applying the Analytic Hierarchy Process (or Analytic Hierarchy Process – AHP) proposed by Saaty in the 70s, a multicriteria analysis method widely used in the support for decision-making involving complexity and subjectivity, on a grading scale ranging from 1 to 9. Seven criteria called thematic factors were established and a weight was assigned to each of these factors, referring to their contribution to the potential for groundwater recharge. It is observed that the hydrogeology criterion resulted in 30.2% of importance, followed by geology 21.4%, soil classes 18.1%, rainfall 12.3%, slope 8.0%, land use and occupation 6.5% and hypsometry 3.6%. Then, the thematic maps were integrated into a GIS environment, generating the groundwater potential map of the municipality divided into three potential classes: low, moderate and high. As a result, 28.38% of the territory has a low potential, 64.32% has a moderate potential and 7.30% has a high potential for groundwater recharge. The results obtained can be used as a tool for the management of water resources, protection of areas with greater potential for underground water recharge, mainly the preservation zones of the municipality.
