ABSTRACT
Groundwater may not necessarily age as well as some wines, but some veiy good aquifers in the world host groundwaters many thousands of years old. The “age” of a groundwater has important implications for water resource management. Using groundwaters that are not actively recharged is mining. On the other hand, groundwater that is part of the modem hydrological cycle is continuously renewed. Its exploitation is potentially sustainable. Deep and/or regional groundwaters can be mixtures of modem and older inputs. However, the presence of even a minor component of modem recharge is important because it indicates a hydraulic connection with an active flow system. Increased pumping may then increase the proportion of the modem contribution.
