Hydrogeology of the Port of Baltimore Confined Aquatic Disposal Pilot Project Area, Masonville, Maryland
2014, Andreasen, D.C., Keeney, L., and Bolton, D.W.
Open File Report 14-02-01
The Maryland Port Administration has proposed to install a Confined Aquatic Disposal (CAD) cell at the Masonville vessel berth for the containment of dredge materials from Baltimore Harbor. Construction of the CAD cell requires excavation of predominantly sandy sediment from the Patapsco Formation (Lower Patapsco aquifer) to a depth of approximately 75 feet below sea level. The CAD cell lies within the outcrop area of the Lower Patapsco aquifer system which overlies the Patuxent aquifer system. Both aquifers are important water sources in northern Anne Arundel County. Since the CAD cell may receive contaminated dredge material, a hydrogeologic investigation was undertaken to determine the possibility of migration of potential contaminants towards Anne Arundel County’s well fields. Results of the investigation indicate that groundwater in the Lower Patapsco aquifer system in the vicinity of the CAD cell flows from high to low topographic elevations and discharges to the Patapsco River. The direction of flow in the vicinity of the CAD cell is south to north, opposite the direction of Anne Arundel County’s well fields. Since the CAD cell is located within the Patapsco River, which is locally an area of groundwater discharge, potential contaminants contained in the fill could not migrate landward. Aquifer testing indicates that the Arundel Clay confining unit, which separates the Lower Patapsco aquifer system from the underlying Patuxent aquifer system, forms a hydraulic barrier which would preclude downward migration of potential contaminants contained in the fill.