Aquifer Recharge Mapping
What is an aquifer?
An aquifer is a body of geologic material that can supply useful quantities
of ground water to natural springs and water wells.
What is aquifer recharge?
Aquifer recharge is the process by which rainwater seeps down through
the soil into an underlying aquifer. There are many natural processes that
determine how much rainwater actually reaches and replenishes an aquifer instead
of being evaporated, consumed by plants and animals, or simply running off
the ground surface into streams, rivers, lakes, and oceans.
Why is it important to map
The protection of our water resources is important for everyone in
the State concerned with the quality and availability of clean drinking water.
Previous water conservation and supply programs have proven to be insufficient
for adequately protecting our drinking-water supplies. About half of the
water used by humans for daily living is extracted from the ground. Therefore
it is important to identify those parts of the State where our ground water
is most likely to be replenished so that we can attempt to protect these
vital resources from pollution and any land-use practices that will decrease
the quality and availability of clean water.
How do we map aquifer recharge
The New Jersey Geological Survey (NJGS) has recently developed a method
for mapping aquifer recharge areas. The method uses rainfall data from climate-monitoring
stations, maps showing how the land surface is currently used (residential,
agricultural, commercial, wooded, pavement, etc.), what kind of soils occur
at the earth's surface, and the extent of wetlands (streams, rivers, lakes,
marshes, and bogs). These data are combined using scientific methods to determine
how much ground water is available in any particular area for recharge to
the local aquifer. How much of this water will actually make it into the aquifer
is also predicted based on how much water can usually be pumped from water
wells drilled into the aquifer. This method has been recently used to show
the location of aquifer recharge areas for Middlesex and Cape May counties.
The NJGS is also currently involved in mapping aquifer recharge areas for
the State's priority watershed areas.
Illustration summarizing the methods used by the NJGS for preparing aquifer
This image uses information from the Middlesex County aquifer recharge
map (Open File Map OFM-21 Ground-Water Recharge and Aquifer-Recharge
Potential for Middlesex County, New Jersey). Ground-water
recharge values range from 0 inches/year in the white areas to 26 inches/year
in the darker colored areas.
refer to Geological Survey Report publication
"A method for evaluating ground-water-recharge areas in New Jersey"
for more detailed information. GSR 32 is available for purchase at the
Maps and Publications Sales Office.
For a recent supplement to this methodology download
Basin Factor Calibration for Ground-Water Recharge Estimation (in Adobe
is an Excel Workbook implementing the ground-water-recharge methodology
based on GSR-32.
For more information about the Surveys Aquifer Recharge Project you can