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Water levels, chloride concentrations, and pumpage in the coastal aquifers of Delaware and Maryland

Water-Resources Investigations Report 87-4229

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Abstract

The Manokin, Ocean City, Pocomoke, and unconfined aquifers of coastal Delaware and Maryland are susceptible to saltwater intrusion from inland movement of offshore water, and from vertical leakage from the bays and deeper aquifer. Comparison of data for water levels, chloride, and pumpage affected during 1974-86 shows that, with the exception of the 44th Street area in Ocean City, Maryland, increased pumpage and lower water levels have not yet caused corresponding increases in chloride concentrations in the confined aquifers. Pumpage from shallow wells near the inland bays has caused localized saltwater intrusion into the unconfined aquifer. Chloride concentrations in the Ocean City aquifer at 44th Street increased from 50 to 200mg/L from 1976 to 1986. Chloride concentrations in water from wells in the Manokin aquifer ranged from 6 to 460 mg/L, whereas those in the Ocean City aquifer ranged from 6 to 260 mg/L. Chloride concentrations in water from the Pocomoke aquifer ranged from 5 to 46 mg/L, and from 11.5 to 46 mg/L in the unconfined aquifer. Seasonal high water levels are affected more by total annual rainfall than by pumpage. Seasonal low water levels generally have declined during most years in areas of heavy pumpage along the coast. Inland, water levels have remained about the same of year to year. (USGS)

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Water levels, chloride concentrations, and pumpage in the coastal aquifers of Delaware and Maryland
Series title:
Water-Resources Investigations Report
Series number:
87-4229
Edition:
-
Year Published:
1987
Language:
ENGLISH
Publisher:
U.S. Geological Survey,
Description:
xii, 106 p. :ill., maps ;28 cm.