What is ground water?
Ground water is water that flows or seeps downward and saturates soil or rock, supplying springs and wells. Ground water often begins as precipitation and soaks into the ground where it is stored underground in rock crevices and in the pores of geologic materials (these are aquifers), the same way as water fills a sponge. The upper surface of the saturated zone is called the water table. More information on ground water may be found at http://water.usgs.gov/public/pubs/FS/OFR93-643/.
When rainwater soaks into the ground, it becomes ground water. Ground water moves into water-filled layers of porous geologic formations called aquifers. If the aquifer is close to the surface, its ground water can flow into nearby waterways or wetlands, providing a base flow. Depending on your location, aquifers containing ground water can range from a few feet below the surface to several hundred feet underground. Aquifer recharge areas are locations where rainwater and other precipitation seeps into the earth’s surface to enter an aquifer. Contrary to popular belief, aquifers are not flowing underground streams or lakes.
