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Aquifer Recharge Mapping






recipitation, Runoff, Infiltration, Evaporation, Transpiration, Aquifer Recharge

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 aquifer recharge?

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 areas?

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 recharge maps

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.

Please refer to Geological Survey Report publication GSR 32 "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 TM99-1 Basin Factor Calibration for Ground-Water Recharge Estimation (in Adobe PDF). DGS99-2 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 contact us.

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Department of Environmental Protection
Geological and Water Survey
P. O. Box 420
Mail Code:29-01
Trenton, NJ 08625-0420

Phone: (609) 292-1185
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