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Article: Groundwater
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- Water:Science and Issues
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CopyrightCOPYRIGHT 2003 The Gale Group Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Groundwater
Water that occurs below the ground and is brought to the land surface by wells or
springs
is referred to as groundwater. Groundwater is a significant part of the hydrologic cycle, containing 21 percent of Earth's freshwater. Groundwater comprises 97 percent of fresh water not tied up as ice and snow in polar ice sheets,
glaciers
, and snowfields. This greatly exceeds the amount of water in streams, rivers, and lakes.
Groundwater is critically important in supplying water to streams and wetlands, and in providing water for
irrigation
, manufacturing, and other uses. In the United States, 80 to 90 percent of available fresh water comes from groundwater. Dependence on this ...