- Published: Tuesday, 14 August 2012 15:34
How Does Groundwater Move?
Groundwater is not a static entity as it flows from a high hydraulic potential to low high hydraulic potential under the influence of gravity. Simply put, the water that falls on an upland area and does not directly run off the landscape will recharge the subsurface and move from that topographic high to the adjacent lower lying areas typically frequented by stream, rivers, lakes and wetlands.
The diagram provides an example of how this works. As well, the amount of time that it takes for water to move through the subsurface is highly variable and dependant on the nature of the sediments it is flowing through and the magnitude of the hydraulic potential.
In some cases, groundwater can move from an upland area, to a receiving water body in a matter of days. In other instances, it can take years, decades or even thousands to millions of years to move large distances. As such, the water that is coming out of one’s well can be older than you may think.
Because the groundwater system is dynamic and replenished annually by recharge, one can consider groundwater as a renewable resource. This does not mean that it can be exploited without having good knowledge of how much is going in, how much is coming out, and what the cumulative effects of withdrawal may be having on dependant ecosystems. Managing groundwater in a sustainable manner comes down to understanding the role it plays in the hydrologic cycle.