Freshwater aquifers are one of the most important natural resources in the world today but we are pumping the groundwater out so fast nature can’t keep up. Some places we’re literally mining the water - once the water is pumped out its gone forever, it isn’t coming back anymore than the gold in a mined out deposit.

 

Think of pumping most underground water to the surface as mining water. When it's gone - like when a gold, copper or rare earth mine runs out of ore - it's gone.

 

http://aheadoftheherd.com/Newsletter/2013/Mining-the-Ogallala.htm