Summary:
- The Ogallala aquifer lies beneath parts of eight U.S. states.
- The water in the aquifer is mostly from the last ice age.
- It is heavily used to irrigate Midwestern farms.
- The use rate is several times faster than the recharge rate.
- When water is pumped from an aquifer, the water table goes down.
- Wells must be drilled deeper to get water.
- Pollutants can seep down through porous rock in recharge water.
- The San Joaquin Valley of California is one of the world’s major agricultural areas.
- The subsidence is due to groundwater depletion.