By John Ferguson South Plainfield Environmental Commission Storm Water Committee
Why is Ground Water Important? Ground water is the primary drinking water source for half of the state's population. Most of this water is obtained from individual domestic wells or public water supplies which tap into aquifers. New Jersey agriculture also depends on a steady supply of clean ground water for irrigation.
What is Ground Water? Where does the water that rains on your home go? After it leaves your lawn, street, or sidewalk, where is it headed? If it soaks into the ground, it becomes ground water. A sizable amount of rainwater runoff seeps into the ground to become ground water. Ground water moves into water-filled layers of porous geologic formations called aquifers. Depending on your location, aquifers containing ground water can range from a few feet below the surface to several hundred feet underground. Contrary to popular belief, aquifers are not flowing underground streams or lakes. Ground water moves at an irregular pace, seeping from more porous soils, from shallow to deeper areas and from places where it enters the Earth's surface to where it is discharged or withdrawn. More than 100 aquifers are scattered throughout New Jersey, covering 7,500 square miles. Aquifers are broken into 5 rankings based on the number of gallons they can provide to wells, highest being greater than 500 gpm (gallons per minute) to the low of only 25 gpm. These wells are used for water supply, irrigation, or industrial use.
Ground Water Complications Humans have an impact on ground water in several ways. One way people influence ground water is by changing where stormwater flows. By changing the contour of the land and adding impervious surfaces such as roads, parking lots and rooftops, people change how and where water goes. When it rains, the stormwater in a developed area is less able to soak into the ground because the land is now covered with roads, rooftops, and parking lots. Another way people affect ground water is by adding potential pollution sources. How the land above ground water is used by people, whether it is farms, houses or shopping centers, has a direct impact on ground water quality. As rain washes over a parking lot, it might pick up road salt and motor oil and carry pollutants. Theses pollutants can move through the soil or storm drains to enter either a stream or local the ground water. South Plainfield’s EPA Superfund Site is an example of pollutants getting into our ground water and the local tributaries. This EPA project continues to be mitigated. Note that a farm or suburban lawn, snow melt might soak fertilizers and pesticides into the ground and can be another source of pollutants.
Controlling Stormwater Flow Managing stormwater to reduce the impact of development on local watersheds and aquifers relies on minimizing the disruption in the natural flow. By designing with nature, the impact of urbanization can be greatly reduced. This can be accomplished by following these principles: • minimizing impervious surfaces. • maximizing natural areas of dense vegetation. • structural stormwater controls such as stormwater management basins • practicing pollution prevention by avoiding contact between stormwater and pollutants.