Reports
Selected geohydrologic characteristics of the Patapsco aquifers at Chalk Point, Prince Georges County, Maryland
1988, Mack, F.K.
Open File Report 88-02-4
Abstract
The Cretaceous Patapsco Formation at Chalk Point consists of thick beds of clay and silt that separate sandy intervals of varying lateral extent. Water-bearing characteristics of three sand ' layers, the tops of which are at depths of about 850 feet, 1,000 feet, and 1,500 feet, have been estimated by pumping tests. The estimated transmissivity of each was 570, 1,500, and 820 feet squared per day, respectively, at the sites tested.
Water levels in the "850-foot" sand declined from 10 feet above sea level to 17 feet below sea level from 1974 to 1986. Water levels in the "1,000-foot" sand, which has been pumped since 1975 at rates ranging from zero to 0.8 million gallons per day, have declined from 15 feet above sea level to 23 feet below sea level from 1973 to 1986. Water levels in the "1,500-foot" sand, which has not been pumped, have declined from 15 feet above sea level to 1 foot below sea level from 1973 through 1986.Chemical analyses of water samples show that except for the slightly high concentrations of dissolved iron in the "850-foot" and "1,000-foot" sands, all constituents tested met the drinking-water standards of the U.S. Environmental Protection Agency.
