Caracterização do fluxo subterrâneo das águas na porção sudoeste da Bacia Representativa de Juatuba

Abstract

The study of underground water movement is of fundamental importance in the integrated management of water resources and nowadays, the inclusion of this kind of water resources inany water managements systems represents a considerable challenge. The characterization of groundwater resources in the southwestern segment of the Juatuba Representative basin is presented in this dissertation in terms of distribution, occurrence, hydrodynamics, reservesand interaction with surface water and soil use. It begins with the identification of geology, climate, morphology, types of soils and vegetation of the basin. Hydrodynamic parameters of the main rock types present in the study area, as well as the establishment of the conceptualmodel were also determinate. The Mato Frio basin is located west of the Iron Quadrangle, included in the granite-gneiss Belo Horizonte complex, where soil types are the most frequent are Oxisol soil and Ultisol soil. The major fracture lineaments that enable the contribution ofdeeper water to runoff are present in the stream of Caboclos (N-S) and in Mato Frio river (NW-SE). Recharge rates in the basin vary around 18% of the precipitation, descending to the ground water by unsaturated parts ranging from 5 m and 20 m in the higher areas of the basin,contributing to the reserves of unconfined and following fractures of bedrock. The average thickness of the free aquifers present in the pore space varies between 30 and 40 m. In the transitional section of the package fractured and porous rocks, where space for storage andmovement of groundwater are increased, flows occur in mixed form and hydrogeological potential is considerable. The basin was separated into six sub-basins from the location of monitoring stations. The specific flow in the basin is 15,03 L/s/km ², which varies in the subbasinswith strong relation to land use. The recession coefficients found for the sub-basins 1, 2, 3 and 4 are close to 0,01 1/day, around 0,005 1/day for sub-basin 5, and reached a value close to 0,02 1/day for sub-basin 6. Variations rates of recharge and recovering from aquifers to baseflow, according to years 2007 and 2008, are between 2,62 million and 5,58 million cubic meters in the basin of river Mato Frio - preliminary evaluation to renewable ground water reserve. The hydrogeologic monitoring net was based this results achieved in study and composed for wells to porous medium and piezometers in fractured medium. The data of netmust be obtained to qualitative and quantitative methods. The tracking network proposal should be implemented gradually, after analyze the data, both conceptual model and the monitoring can be improved.