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| Publications— Water-Resources Investigations Report |
By Richard L. Walker
View the report in Portable Document Format (PDF) WRIR 00-4012 (1.0 KB)
Since the 1970’s, hexavalent chromium
has been detected in concentrations as great as
1.0 milligram per liter in wells at the Puchack
well field operated by the Camden City Department of Utilities, Water Division (Water Department), forcing the Water Department to
progressively remove five of its six wells from service between 1975 and 1988. The wells in
the Puchack well field range in depth from 140 to 220 feet and are screened in the Lower
Potomac-Raritan-Magothy aquifer. The Water Department has continued to pump Puchack
Well 1 to maintain a hydraulic gradient toward the well field in an attempt to limit contaminant
migration. In late 1997, concerns about treating the water withdrawn from Puchack Well 1 led
water managers to consider temporarily discontinuing the pumping.
In the spring of 1998, the U.S. Geological Survey (USGS), in cooperation with the New
Jersey Department of Environmental Protection, began a preliminary assessment of the
potential effects of temporarily removing Puchack Well 1 from service. Water levels in
the Lower Potomac-Raritan-Magothy aquifer were measured during both pumping and nonpumping
conditions to determine the direction and velocity of ground-water flow and the
results were compared.
Data collected in late March and early April 1998 indicate the presence of a ground-water
divide between the Puchack well field and the Morris and Delair well fields when
Puchack Well 1 was being pumped. A similar divide also was present when the well was not
being pumped. The position and persistence of this divide limits the probability that contaminants
in the vicinity of the Puchack well field will reach the Delair and Morris well fields during
either pumping condition. Another divide southeast of Puchack Well 1 while the well was
being pumped was no longer evident when the pumping was stopped and water levels had
recovered. Under non-pumping conditions, ground water between Puchack Well 1 and this divide could begin to migrate toward other
large pumping centers to the southeast. The average linear ground-water velocity along an
arbitrarily selected southeast-trending flow path was estimated to be from 221 to 332 feet
per year. This estimate indicates that any contaminated ground water that may be present
within the area influenced by pumping at Puchack Well 1 may begin to move toward the
pumping centers less than 2 miles to the southeast
if Puchack Well 1 is either temporarily or permanently removed from service.
Abstract
Introduction
Hydrogeologic Setting
Study Methods
Effects of Pumping on Ground-Water Flow
Ground-Water Levels
Ground-Water Flow Direction
Estimated Average Linear Ground-Water Flow Velocity
Conclusions
References Cited
Suggested citation:
R.L. Walker, 2001, Effects of pumping on ground-water flow near water-supply wells in the Lower Potomac-Raritan-Magothy aquifer,
Pennsauken Township, Camden County, New Jersey: U.S. Geological Survey Water-Resources Investigations Report 00-4012, 12 p.
If you have Adobe® Acrobat® or Adobe® Acrobat®Reader® installed on your computer, you may view and print the PDF version of this report. Acrobat Reader, is a free download from Adobe Systems Incorporated.
View the report in Portable Document Format (PDF) WRIR 00-4012 (1.02 MB)
For more information about USGS activities in New Jersey contact:
Director
USGS New Jersey Water Science Center
810 Bear Tavern Road
West Trenton, NJ 08628
Telephone: (609) 771-3900
Fax: (609) 771-3915
or access the USGS Water Resources of New Jersey home page at:
http://nj.usgs.gov/.
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