Digital Geodata Series
DGS02-3 Ground-Water Recharge for New Jersey

Abstract

Ground-water recharge (GWR) is defined as the water that infiltrates the ground and reaches the water table regardless of the underlying geology. It supports aquifer recharge, stream baseflow and wetlands. It is estimated in New Jersey using the methodology outlined in NJ Geological Survey Report GSR-32 "A Method of Evaluating Ground-Water-Recharge Areas in New Jersey" by E. G. Charles and others (1993). Application of this method using the Arc/Info geographic information system (GIS) produced 19* county and 20* watershed management area (WMA) ground-water recharge, GIS coverages. The county recharge coverages were created by overlaying three coverages; 1) soils, 2) land use and land cover (LULC); and 3) municipalities. These three coverages provided the following attributes: soil series names, land-use and land-cover categories, and climate factors; respectively. These data were then used to calculate ground-water recharge values using the following equation for each area in the coverage:

ground-water recharge = (recharge factor x climate factor) - recharge constant

The recharge factor and constant are determined by the cross tabulation of LULC and soil series. The climate factor is determined using zonal statistics and is a ratio of precipitation over potential evapotranspiration.

The WMA coverages were created by combining all the county coverages of each WMA and then "clipping" the result with the WMA boundary. Calculated ground-water recharge values from each area in the coverages were rounded to the nearest inch and ranked into 5 categories based upon the natural breaks in the percentage of total volume, as shown in this table for Mercer Co. or this table for Watershed Management Area 8 (Upper Raritan).

Other attributes included in the coverages are soil symbols, hydrologic soil group, hydric soil indication, soil descriptions (where found); LULC category codes, climate factor, municipality and the statewide GWR rankings which were generated by combining all of the county GWR coverages and ranking the result. 

The coverages were converted to shapefiles which were compressed into individual zip files**. Downloads of the 19 county and 20 watershed management areas are available along with metadata and ten by seventeen inch county and  WMA PDF** maps were also produced.

* Recharge for Essex County has not been calculated at this time, and Hudson County's was not calculated due to the lack of current soil survey and soils coverage, therefore only parts of WMAs 4, 5, 6 , and 7 have recharge calculated.

** Zip files may require additional software to decompress them such as WinZip™. PDF  (portable document format) files also require additional software capable of accessing them such as Adobe Reader™ . The mention of  third party software products does not constitute an endorsement of these products by the NJGS. The NJGS does not support these products nor is the NJGS liable for any problems or damages arising from their download, use and/or misuse.

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Index Maps
New Jersey Counties	NJ Watershed Management Areas

County Ground-Water Recharge Downloads	Watershed-Management Area Ground-Water Recharge Downloads
Atlantic Co. (5 mb),  Metadata,  PDF map (5 mb)	WMA 1: Upper Delaware (6 MB),  Metadata,  PDF map(8 MB)
Bergen Co. (2 mb),  Metadata,  PDF map (6 mb)	WMA 2: Wallkill (3 MB),  Metadata,  PDF map (6 mb)
Burlington Co. (7 mb),  Metadata,  PDF map (5mb)	WMA 3: Pompton, Wanaque, Ramapo (2 mb),  Metadata,  PDF map (7 mb)
Camden Co. (2 mb),  Metadata,  PDF map (5 mb)	WMA 4: Lower Passaic, Saddle (1 mb),  Metadata,  PDF map (6 mb)
Cape May Co. (2 mb),  Metadata,  PDF map (4 mb)	WMA 5: Hackensack, Pascack (1 mb),  Metadata,  PDF map (6 mb)
Cumberland Co. (7 mb),  Metadata,  PDF map (6 mb)	WMA 6: U. Passaic, Whippany, Rockaway (3 mb),  Metadata,  PDF map (7 mb)
Gloucester  Co. (3 mb),  Metadata,  PDF map (5 mb)	WMA 7: Arthur Kill (1 mb),  Metadata,  PDF map (6 mb)
Hunterdon Co. (3 mb),  Metadata,  PDF map (6 mb)	WMA 8: North & South Branch Raritan (4 mb),  Metadata,  PDF map (6 mb)
Mercer  Co. (2 mb),  Metadata,  PDF map (3 mb)	WMA 9: Lower Raritan, South, Lawrence (3 mb),  Metadata,  PDF map (7 mb)
Middlesex  Co. (3 mb),  Metadata,  PDF map (5 mb)	WMA 10: Millstone (3 mb),  Metadata,  PDF map (6 mb)
Monmouth  Co. (4 mb),  Metadata,  PDF map (5 mb)	WMA 11: Central Delaware (2 mb),  Metadata,  PDF map (6 mb)
Morris Co. (5 mb),  Metadata,  PDF map (6 mb)	WMA 12: Monmouth (3 mb),  Metatdata,  PDF map (7 mb)
Ocean Co. (5 mb),  Metadata,  PDF map (7 mb)	WMA 13: Barnegat Bay (5 mb),  Metadata,  PDF map (8 mb)
Passaic Co. (2 mb),  Metadata,  PDF map (5 mb)	WMA 14: Mullica (5 mb),  Metadata, PDF map (8 mb)
Salem Co. (4 mb),  Metadata,  PDF map (5 mb)	WMA 15: Great Egg Harbor  (5 mb),  Metadata,  PDF map (8 mb)
Somerset Co. (3 mb),  Metadata,  PDF map (5 mb)	WMA 16: Cape May (2 mb),  Metadata,  PDF map (6 mb)
Sussex  Co. (5 mb),  Metadata,  PDF map (5 mb)	WMA 17: Maurice, Salem, Cohansey (9 mb),  Metadata,  PDF map (8 mb)
Union Co. (1 mb),  Metadata,  PDF map (5 mb)	WMA 18: Lower Delaware (4 mb),  Metadata,  PDF map (7 mb)
Warren Co. (3 mb),  Metadata,  PDF map (6 mb)	WMA 19: Rancocas (3 mb),  Metadata,  PDF map (7 mb)
All Counties (108 mb)	WMA 20: Assiscunk, Crosswicks, Doctors (3 mb),  Metadata,  PDF Map (5 mb)
* Recharge for Essex County has not been calculated at this time, and Hudson County's was not calculated due to the lack of current soil survey and soils coverage, therefore only parts of WMAs 4, 5, 6 , and 7 have recharge calculated.