Caracterização potenciométrica e de capacidade específica dos poços da área urbana de Monte Carmelo - MG

Abstract

The municipality of Monte Carmelo, Minas Gerais, is in the hydrographic district of the Atributaries of Minas Gerais of the Upper Paranaíba, which, together with the district of the Araguari River, both in the Upper Paranaíba Hydrographic Basin, concentrates the largest number of underground and surface water concessions in the state of Minas Gerais. Half of the public water supply in Monte Carmelo comes from the exploitation of groundwater. The main objective of this study was to contribute to the management of the municipality's water resources by understanding some aspects of the local aquifer units. Data on flow, static level, dynamic level and hydraulic head of deep tubular wells in the municipality of Monte Carmelo were analyzed from the databases of the Department of Water and Sewage (DMAE) and the State System of Environment and Water Resources (IDE-SISEMA). Through the interpretation and modeling of these data using the SURFER software, the potentiometric map and the specific capacity map of the wells in the urban area were generated. All the wells analyzed were considered to belong to unconfined aquifers, called the Monte Carmelo granite aquifer and the Araxá metamorphic aquifer, both of the fractured type. However, it was not possible to differentiate the wells between the two aquifers due to insufficient data on the lithological profiles. The aquifers had an average depth of 11.84 m; the shallow water table in the urban area indicates high vulnerability to contamination, requiring further studies in this regard. The average flow rate of the wells analyzed is 9.70 m3/h and the average specific capacity is 0.43 m3/h/m. This specific capacity value is considered medium to low, even for fractured aquifers; its great variability is also expected for this type of aquifer. Some wells with specific capacity values greater than 1 m3/h/m are located in recharge areas, identified near the sources of the Mumbuca, Pirapitinga and Lambari streams. The main discharge area of aquifers in the urban area of Monte Carmelo is along the Mumbuca stream. During dry seasons, the underground dynamics can be altered, therefore, there is no possibility of managing the municipality's water resources without studies on the integration of surface and underground flows.