Ground water is water which lies in an aquifer below ground surface. Major aquifers are generally contained in deposits of gravel or other highly porous alluvial material. Aquifers are recharged by seepage from bodies of water and by precipitation. Some aquifers, such as the Ogallala Aquifer beneath the Great Plains of North America, contain water from earlier wetter periods. Intensive withdrawal from such aquifers may exceed the rate of recharge, water mining.

External links and further readingEdit

• USGS Ground Water Information Pages
  • Ground Water Atlas of the United States (online)
  • James A Miller, U.S.G.S, Ground Water Atlas of the United States, U.S. Dept. of the Interior, U.S. Geological Survey (2000) ISBN 0607941790 ISBN 9780607941791 This large expensive hardbound book is generally not available used or at bookstores. To find at a library try WorldCat, to purchase try Order. There you may order softbound maps covering specific regions at a nominal cost.
• National Ground Water Association The National Ground Water Association is a membership organization for ground water professionals and interested parties. In 2008 basic membership was $105 a year. There is considerable public information on the site, but premium information is members' only.
  • Virtual Museum of Ground Water History