“After all, water from underground meets 20 percent of U.S. water demand for drinking, crop irrigation and everything else. It also provides the base flows that keep many rivers and streams from drying up during the summer months.
So groundwater is crucial to our economies and ecosystems, yet it’s out of sight – and usually out of mind, as well.
Which is why a most-endangered aquifers list might help.
On such a list I would name the Ogallala Aquifer beneath the Great Plains, which supplies 27 percent of the nation’s irrigated farmland and has undergone decades of depletion. I would include California’s Central Valley aquifers, which are greatly over-pumped to grow the nation’s fruits and vegetables.
I would add coastal aquifers in Florida and the Carolinas, which are threatened by the intrusion of seawater. In some areas, heavy pumping from those aquifers has reversed the hydraulic gradient: instead of groundwater flowing out to sea, ocean water moves in, polluting fresh drinking water with salt.”
Read more: National Geographic