Maryland Coastal Plain Aquifer Information: Hydrogeologic Framework
2013, Andreasen, D.C., Staley, A.W., and Achmad, G.J
Open-File Report 12-02-20
A comprehensive, regionally consistent hydrogeologic framework of Maryland’s Coastal Plain was compiled as part of a long-term multi-phase assessment of the Maryland Coastal Plain aquifer system. The assessment was conducted by the Maryland Geological Survey and the U.S. Geological Survey, with funding support from the Maryland Department of the Environment. It was initiated in response to recommendations of the 2004 Maryland Advisory Committee on the Management and Protection of the State’s Water Resources. Geophysical logs, published reports, and file data from 901 boreholes were used to define the surface altitudes of the tops of 16 aquifers (or aquifer systems) and 14 confining units, ranging in age from Lower Cretaceous to Holocene. The altitude of the top of pre-Cretaceous basement rock was also mapped. Gridded arrays of the surface altitudes, aquifer extents, and outcrop/subcrop areas were created for input into a geographic- information-system-based aquifer information system. In addition, hydraulic properties (transmissivity, hydraulic conductivity, and storage coefficient) were compiled from the literature for 328 wells, and properties for 310 wells were analyzed from file aquifer-test data. All data were compiled and are collectively available as the Maryland Coastal Plain Aquifer Information System and in the MGS Open-File Report No. 12-02-20.
Location of Study Area and Hydrogeologic Setting
The study area covers the entire portion of Maryland's Coastal Plain Province, approximately 8,000 square miles (mi2), extending from the Fall Line on the western side of Chesapeake Bay to the Atlantic Ocean. To adequately develop the hydrogeologic framework along the state boundaries, the study area extends into Delaware, the Northern Neck of Virginia, and Washington D.C.; however, those areas are not the focus of this investigation.
Maryland Coastal Plain Aquifer Information System
The Maryland Coastal Plain Aquifer Information System (MCPAIS) is a GIS-based tool that stores and accesses information about Maryland Coastal Plain ground-water resources for use in water-resource management, ground-water-flow modeling, and other hydrogeological analyses. The MCPAIS is a long-term project conducted by the Maryland Geological Survey (MGS) and U.S. Geological Survey (USGS), with funding and planning support from Maryland Department of the Environment (MDE). The aquifer information system incorporates geographical and tabular ground-water-related databases from the U.S. Geological Survey (USGS), Maryland Geological Survey (MGS), and Maryland Department of the Environment (MDE). The system, which is currently in use by MDE for evaluating ground-water appropriation permits, contains layers that display the hydrogeologic unit surfaces, extents, hydraulic properties, water-level data, and selected well records. The system also includes prototype layers of groundwater and surface withdrawal data (in Anne Arundel, Baltimore, Cecil, Harford, Howard, Montgomery, and Prince George’s Counties, and Baltimore City) and selected water-quality data (arsenic) from the Aquia and Piney Point aquifers. In this study the hydrogeologic framework and hydraulic properties were compiled for the aquifer information system.