Reports
Hydrogeologic data from the Heritage Green test site, La Plata, Maryland
1999, Mack, F.K.
Open File Report 99-02-11
Key Findings
Testing preliminary to the expansion of the water supply of the Town of La Plata provided an opportunity to study the 1,770-foot thickness of Coastal Plain sediments overlying Triassic (?) "basement" rocks in the Heritage Green area. Drill cuttings, drillers' logs, and geophysical logs from a probe hole 1,871 feet deep (CH Ce 57) show that most of the sediments are fine-grained with some thin layers of medium to coarse-grained sand in the Patuxent and lower Patapsco Formations.
Data from an aquifer test of the deepest sands in the Coastal Plain section showed that the transmissivity of the Patuxent aquifer is about 100 feet squared per day. Chemical analyses indicated that water from the Patuxent aquifer is a sodium bicarbonate type with 602 milligrams per liter dissolved solids, 96 milligrams per liter dissolved chloride, 1.2 milligrams per liter dissolved fluoride, and 450 micrograms per liter dissolved iron.
Transmissivity values derived from a test of several sands in the lower Patapsco aquifer ranged between 830 and 1,100 feet squared per day. Chemical analyses indicated that water from the lower Patapsco aquifer is also a sodium bicarbonate type with 302 milligrams per liter dissolved solids, 1.86 milligrams per liter dissolved chloride, 1.14 milligrams per liter dissolved fluoride, and 249 micrograms per liter dissolved iron.
