Groundwater and Aquifers


Groundwater and Aquifers

Beneath the Pine Barrens there are a few sandy layers that contain enough water to be exploited for human use. These water bearing zones are known as aquifers.

Water Cycle GW Large
Aquifer recharge.  Credit: USGS

These aquifers are separated by less porous silt and clay layers that act as semi-confining barriers, and prevent flow between aquifers. There are only a few aquifers beneath the Pine Barrens that can be used for domestic water use. From the oldest to youngest they are the Potomac-Raritan-Magothy (also referred to as the Lower, Middle and Upper aquifers), Englishtown, Wenonah/Mount Laurel, Piney Point and Kirkwood-Cohansey aquifer system. From an ecological perspective, the most important aquifer is the Kirkwood-Cohansey aquifer, since it is the shallowest, and provides water to streams, rivers and wetlands.

It is from these aquifers that most people living in the Pine Barrens get their water for everyday use. Some people have their own wells, others rely on the local water company to provide them with water, either way, most if not all of that water is derived from groundwater sources. Some towns in the western part of the Pine Barrens now supplement their groundwater needs with treated water from the Delaware River.

Kirkwood-Cohansey Aquifer

All of the aquifers beneath the Pinelands are important since they provide drinking water for residents of the area and because they are limited in number. From an ecological perspective, however, the shallow Kirkwood-Cohansey aquifer systemhas special significance.

The Kirkwood-Cohansey is the life blood of the Pine Barrens. Ninety percent of the water in streams, rivers and wetlands is supplied by this aquifer system in the form of baseflow. In addition, since water in this aquifer often occurs less than a few feet beneath ground surface, it directly supplies water to the roots of Pine Barrens trees, shrubs and plants. Some of which are rare, threatened or endangered. It is for this reason that the aquifer is referred to as the shallow water table aquifer.

On average the Pinelands receives about 44 inches of precipitation annually. About half of this water is transpired by vegetation or evaporates. A small amount enters streams as storm runoff. Only about 17 to 20 inches annually actually enters the ground. Some of this water works its way through the soil and eventually reaches the water table. From here a portion flows into nearby streams and wetlands providing the necessary water to sustain these ecosystems.

Interactive Aquifer and Watershed: Explore the interactive aquifer at the South Jersey Water Savers website.

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Essential Facts about the Aquifer
  • It contains more than 17 trillion gallons of fresh water and lies beneath most of southern New Jersey.
  • Water flowing out of the ground from the aquifer represents about 90 percent of all water flowing in the streams and rivers in the Pinelands and southern New Jersey.
  • It supplies clean, fresh water to the Delaware River and Bay.
  • It is a “surficial” aquifer meaning it is exposed at the land surface in our wetlands, lakes and streams.
  • The aquifer is comprised mostly of water-saturated layers of sand and fine gravel and some clay-like material and extends from the land’s surface just beneath our feet to depths of up to about 1000 feet near the shore.
  • The aquifer is the groundwater supply for about one million residents and visitors in southern New Jersey, including shore communities.
  • Water pumped from the aquifer helps irrigate about 200,000 acres of farmlands.
  • Fresh water flowing from the aquifer into Barnegat Bay, Delaware Bay, Great Bay and Great Egg Harbor Bay and is critical to the health of fisheries and shellfish beds.
Upper Batsto River
The Kirkwood-Cohansey aquifer is the source of water for all Pinelands rivers like the Batsto River pictured here. © Albert Horner

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