Groundwater Age, Trends and Yield

Groundwater can be either very young, representing recent recharge to the subsurface, or it can exist as very old water that has been interacting with the rock and sediments that host it. The age of groundwater can span anywhere from two weeks for very local flow systems to millions of years for deep, regional flow systems. For example, a shallow flow system would constitute recharge in a small upland area followed by discharge to an immediately adjacent low-lying area. The distance of groundwater travel may be on the order of 100s of metres. In contrast, groundwater flow in deeper regional flow systems can travel several 100s to 1000s of kilometres. A classic example of a deep regional flow system in Alberta is the general flow of groundwater from the recharge area in the western part of the province near the Rocky Mountains cordillera and foothills region eastward across the plains areas towards the province of Saskatchewan. The time that it can take for recharged groundwater to travel this distance is in the order of several million years.