Summary: The demand for water in many areas of the Nation is being met by overdrafting ground water, extracting more ground water than will be replenished over a long period of time. Overdrafting is not necessarily bad; however, if it is continued indefinitely, the resulting problems may ultimately affect the Nation's ability to meet ever-increasing demands for food and other agricultural products. Therefore, GAO undertook a review of the numerous problems associated with ground water overdrafting to determine the seriousness of the overdrafting problems in States and communities that have not implemented ground water controls.
In its review, GAO found that overdrafting is most serious in the arid and semiarid Western States where irrigation of crops accounts for over half of all ground water use. GAO found that several problems can result from overdrafting, such as: (1) land subsidence; (2) saltwater intrusion into freshwater aquifers; (3) reduced surface water flows; (4) increased energy consumption; and (5) disruption of social and economic activities. Some States, such as Colorado, New Mexico, and Florida, have generally succeeded in controlling overdraft of their underground aquifers. However, other States, such as California and Arizona, currently impose little if any control on the use of ground water; and both States suffer serious overdraft problems. Although the Federal Government only manages water resources on Federal lands, it has assisted States with overdraft problems by constructing multipurpose water development projects to replace or supplement ground water.
