Improper mining could kill the Kabul River and poison the aquifer for generations to come.
In west-central Kansas, up to a fifth of the irrigated farmland along a 100-mile swath of the aquifer has already gone dry.
Palestinians are only allowed to dig wells 150 meters deep, but Israelis dig to the aquifer.
An underground layer of permeable rock, sediment (usually sand or gravel), or soil that yields water. The pore spaces in aquifers are filled with water and are interconnected, so that water flows through them. Sandstones, unconsolidated gravels, and porous limestones make the best aquifers. They can range from a few square kilometers to thousands of square kilometers in size.