Discharge – Recharge
Eventually, groundwater comes to the surface. It may be pumped from a well that feeds it through a garden hose or faucet in your home. Or it may flow into streams, rivers, lakes, marshes or oceans as “discharge.”
Discharge from groundwater contributes to the flow of surface waters in rivers, streams and can fill lakes. In dry periods, the flow of streams may be supplied entirely by groundwater.
An obvious question is
Do aquifers ever run dry?
… or do they continue to get more water?”
The answers are “YES” and “YES.”
Groundwater supplies can actually run dry when the amount pumped to the surface by wells lowers the water table or when there is not enough recharge (thus making the zone of saturation smaller and lowering the water table). Groundwater supplies are replenished by rain and snowmelt that occur each year. We call this “recharge”. Water from melting snow and rainfall seeps into the soil and percolates down into the saturated zone. Places where this happens are called recharge areas. In the summer and fall months, recharge areas may appear as dry land. In the late winter and spring, the same areas are full of water that will eventually percolate down into the saturated zone of the aquifer below.