The recession coefficient (α) indicates the production rate of the baseflow, that represents the part of the river flow which is predominately maintained by groundwater restitution. It can be obtained through hydrographic analysis. This coefficient allows the calculation of important parameters, such as aquifer transmissivity, renewable groundwater reserves, and low flow in drainage channels that usually are obtained through other hydrological indexes, such as the Q7,10, frequently used in the management of surfi cial hydrological resources. The studied basins are located in the Central-Southern region of the Minas Gerais State, in areas of granite-gneissic rocks, with similar vegetation, climate and landuse. The results were satisfactory, showing that the determination methods for the recession coefficients may be used to characterize groundwater production in the hydrographic basins of the crystalline basement. The groundwater discharged into the drainage systems is greater in areas with smoother relief, indicating that they constitute the best recharge areas.
Groundwater; recession; baseflow
