Ground-water flow and the possible effects of remedial actions at J-Field, Aberdeen Proving Ground, Maryland
Year: 1995
Type: report
Abstract: J-Field is located in the Edgewood Area of Aberdeen Proving Ground, Md., and ha" been used since World War II to dispose of munitions, explosives, chemical-warfare agents, and industrial chemicals.Ground-water, surface-water, and soil contamination has resulted from these past activities.The U. S. Geological Survey finite-difference model was used at J-Field to better understand ground-water flow at the site and to simulate the effects of remedial actions.Two layers were used in the model to simulate a surficial aquifer and a confined aquifer.A confining unit separates these two units and is represented in the model by the leakance between the two layers.The area modeled is 3.65 square miles; the model was constructed with ?variably spaced 40 X 38 grid.The horizontal boundaries and the bottom boundary of the model are all noflow boundaries.All the simulations were conducted under steady-state conditions.Tidal wetlands and estuaries were simulated as fixed heads and nontidal wetlands were simula*?d using either the river subroutine or the drain subroutine.Ground water at all three of the solid-waste-management units under investigation flows from disposal pit areas toward discharge areas in the estuaries or in wetlands.Remedial actions were not simulated at the white-phosphorus disposal area, because rapid flow through tte system has allowed much of the contamination at that site to discharge offshore.Simulations si ow that capping the riot-control-agent and toxic-materials disposal areas with an impermeable cover is effective at slowing advective ground-water flow by about 0.7 and 0.5 times, respectively.Barriers to horizontal ground-water flow were simulated and effectively prevented the rrovement of contaminated ground water toward discharge areas, such as wetlands.A horizontal hydraulic conductivity less than 0.005 feet per day was required for the simulated 10-foot-wide barriers to be effective.Extraction wells were simulated as a way to contain ground-water contamination ard as a way to extract contaminated ground water for treatment.Simulations indicated that twc wells pumping 5 gal/min (gallons per minute) each at the toxic-materials disposal area and a single well pumping 2.5 gal/min at the riot-control-agent disposal area would be effective for containing contaminated ground-water at these sites.A combination of barriers to horizontal flow both north and south of the toxic-materials disposal area and a single extraction well pumping at 5 gal/min can be used at the toxic-materials disposal area to extract contaminated ground water an-1 to prevent pumpage of wetland water.In the pumpage scenarios at the toxic-materials disposal area, ground-water discharge to the wetland is captured by the wells and could result in a redrction in the wetland area. Ground-water flow at J-field, Aberdeen Proving Ground, Maryland
DOI: 10.3133/wri954075
Author: W.B. Hughes
Language: English
Subfield: Environmental Engineering
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
OpenAlex ID: W132254486