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(1) The water table is the altitude (below ground) where the water level in a well will rise to when the well taps a confined aquifer. |
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(2) If you ate canned corn last night, there is a good chance that it was irrigated with
ground water. |
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(3) Land subsidence occurs in areas underlain by highly-fractured granite, which is readily dissolved by moving ground water, especially when the water is slightly acidic. |
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(4) Water can flow in streams even during periods of drought due to ground water seeping into the streambanks. |
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(5) Artificial recharge to an aquifer can occur when people inject water down into a well to force it back into an aquifer so they can withdraw it later. |
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(6) Big cities drill deep wells to tap naturally heated water because the heat kills bacteria and the water needs less treatment. |
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(7) Bottled water often is advertised as "artesian well water." Artesian water is ground water that is naturally filtered by an aquifer composed of fine, porous material—this artesian water can be put directly into bottles. |
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(8) The heaviest users of ground water for drinking water and other public uses are the Southwest desert States, where surface water is scarce. |
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(9) The porosity and permeability of an aquifer define its ability to yield water to wells in productive amounts. |
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(10) For some wells along the coastline that are drilled into porous aquifers, pumps are turned off twice a day (during periods of high tides), since tides temporarily raise saline ground-water levels, causing saltwater intrusion into freshwater aquifers. |
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(11) Cities prefer to use ground water for drinking-water supplies because surface water is in constant contact with streambeds and, thus, contains a higher concentration of dissolved minerals and other substances that must be removed. |
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(12) Excessive pumping of a well can reverse the natural flow of ground water into a river, causing the water level in the river to fall. |
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(13) Most wells are shallow because a significant amount of water cannot be obtained from wells deeper than about 1,000 feet. This is because it is difficult for pumps to overcome the force of gravity and push water up to the land surface. |
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(14) The most productive wells tap large open areas in subsurface rocks, including horizontal fissures, caverns, and lava tubes, which have connections to the land surface, thus allowing the aquifer to be quickly recharged by precipitation. |
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(15) A cone of depression occurs when you drop your scoop of ice cream (made with ground water) on the ground on a hot summer day. |
U.S. Department of the Interior | U.S. Geological Survey
