Ground-water supplies for industrial and urban development in Anne Arundel County
1962, Mack, F.K. and Richardson, C.A.
This report is an appraisal of ground-water resources in a rapidly growing area in the Maryland coastal plain. It was prepared to guide County and State planners in effectively locating new water-using industries, commercial establishments, and public water supplies.
Bounded on the north by Baltimore City, on the east by the Chesapeake Bay, and on the west by the Patuxent River, Anne Arundel County includes an area of 417 square miles of land surface and is situated on a part of the Atlantic Coastal Plain which is adjacent to the Piedmont province. About half of the land surface is less than 100 feet above sea level and less than one square mile is more than 300 feet above sea level. Estuaries of the Chesapeake Bay extend inland to the center of the County. The climate is humid and temperate with a mean annual temperature of 56° F and an average precipitation of about 44 inches.
The County is underlain by a wedge-shaped mass of unconsolidated coastal plain sediments of Cretaceous, Tertiary, and Quaternary age which overlie much older consolidated crystalline rocks. The wedge of sediments is less than 50 feet thick in the northwestern part of the County but thickens to about 2,000 feet in the southeastern part of the County. The five major aquifers of the County—the Patuxent, the Patapsco, the Raritan, the Magothy, and the Aquia Formations—dip gently toward the southeast.
An average of 20 mgd (million gallons per day) of water were used in Anne Arundel County in 1960. About 70 per cent of that quantity was from groundwater sources within the County and 30 per cent was from surface-water sources.
The investigation shows that approximately 80 mgd is available from the artesian aquifers, and that an additional 50 mgd may be available from water table aquifers. Thus, the limit of water available is on the order of 130 mgd.
A systematic appraisal of the ground water available from each of ten localities in the County shows that details of ground-water conditions vary from place to place. The thinness of the unconsolidated sediments in the northwestern part of the County limits the amount of drawdown available and thus the amount of water available from individual wells. Geologic conditions will permit the removal of large quantities of water from the eastern part of the County, but overexploitation of the ground water there would lower hydraulic heads in the aquifers and eventually induce contamination by brackish water from the Chesapeake Bay or its estuaries.