What is “Groundwater?”

Question: In my area, water is supplied by a well and the water comes from underground. What is “groundwater”? Where does it come from, and how can I protect it?
 
Answer:
Fresh water is an increasingly precious resource around the world. As global leaders work to ensure that humans have safe and sufficient water to drink, to promote agriculture, and for other vital activities, the importance of understanding ground water grows.
 
Ground water is the water that soaks into the soil from rain or other precipitation and moves downward to fill cracks and other openings in beds of rocks and sand. Of all the fresh water in the world (excluding polar ice caps), 90 percent is ground water. Surface water (lakes and rivers) only make up three percent of our fresh water. Scientists estimate U.S. ground water reserves to be at least 33,000 trillion gallons – equal to the amount discharged into the Gulf of Mexico by the Mississippi River in the past 200 years.
 
Almost half of the U.S. population depends on ground water for its drinking water supply – be it from either a public source or private well. In rural areas, the number is about 96 percent. The United States uses 83.2 billion gallons per day of fresh ground water for public supply, private supply, irrigation, livestock, manufacturing, mining, thermoelectric power, and other purposes.
 
Groundwater is a renewable resource, although renewal rates vary greatly according to environmental conditions. In most parts of the United States, water removed from the ground is constantly replaced, although in some parts of the country such as arid and semiarid regions, a low rate of replenishment is far exceeded by the rate of ground water pumping, resulting in serious problems of ground water mining. Adequate time is needed to allow replenishment of underlying ground water reservoirs (aquifers); also such areas must be properly managed in order to prevent water-soluble waste products stored in these areas from infiltrating and polluting the underground supply.
 
As ground water moves through the ground, it dissolves some of the minerals that it comes in contact with. Those dissolved minerals give ground water its chemical character or quality. In many cultures throughout the world, that specific character is appreciated by thirsty consumers as much as the taste and character of a favorite cola, beer, or wine. Many bottled waters come from ground water reserves.
 
Ground water is naturally filtered by the earth that holds it. It can, however, be contaminated by pollutants that come into contact with the earth’s surface. Care should be taken at the household, local, national, and global levels to protect ground water from pollutants. To help protect ground water and the wells systems that distribute it:
 
– Always use licensed or certified water well drillers and pump installers when a well is constructed or serviced, or when the pump is installed or serviced.

– Keep hazardous materials away from any well. Never dump such materials, motor oil, or anything else that could impact water quality onto the land surface, into a hole or pit, or into a surface water supply.
 

Source: Fact Sheets, World Water Monitoring Day. Compiled and reprinted with permission of the National Ground Water Association, Copyright 2006.

 
Originally posted in “On Eagles’ Wings” November 8th 2006

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