Site 3 - Supplyside Landfill
The Supplyside Landfill began operations in 1969 and was used until 1983. The landfill boundaries are roughly 450 feet wide by 1,400 feet long, covering about 15 acres. There are conflicting reports of the number of cubic yards of refuse that were disposed at the landfill, which was constructed of four parallel trenches. Historical documents indicate that wastes were not burned, and no hazardous wastes were disposed at the landfill. Site 3 was used to dispose of primarily office and other solid wastes.
According to the Round 9 (June 2014) Groundwater Monitoring Report, the groundwater beneath Site 3 flows towards the north. The installation of groundwater wells (other than environmental monitoring wells) in this area is prohibited to prevent the consumption of groundwater.
Site 3 is currently covered by grass and other vegetation, and the site is fenced to limit access. Activities at the property are limited to those actions that are conducted to make sure that the remedy is functioning properly, such as groundwater monitoring and inspecting cover materials and methane gas vents. The Navy recently placed solar panels across the site; and plans to maintain the landfill cover, gas vents, and fence.
Investigations were conducted at Site 3 in 2001 to determine the presence and extent of methane and VOCs. Additional investigations were conducted in 2002 and 2003 to determine the thickness and other properties of the existing clay cap, and to collect groundwater samples from beneath the wastes.
A clay cap was placed on the landfill in 1985. The construction of the cover was completed by the Navy Construction Battalion 401, which was stationed at the NSGL at the time. Between 1999 and 2001, the Navy removed the railroad tracks, filled areas between the trenches, and placed additional clay on top of the landfill.
A new cover was constructed on the Supplyside Landfill in 2004. The landfill was re-graded to create a flat surface with a gradual slope across the top of the landfill. A three percent slope was created on the top surface for drainage and erosion control, and a 3-to-1 slope was created around the perimeter of the landfill. The final cover construction included of 18 inches of low permeability clay with 6 inches of topsoil to support vegetative growth. A passive vent system was installed that consisted of shallow trenches excavated in the waste material, with horizontal collector pipes and vertical vent pipes. Asbestos-containing material was identified in the topsoil cover in 2004. Material for the clay and topsoil were generated from site grading activities at a construction site located at the Recruit Training Center. Geotextile fabric and additional clay were installed in 2005 over a 330-foot by 550-foot area at the north end of the landfill to cover about 12,000 cubic yards of soil with asbestos-containing material (non-friable transite).
A perimeter fence around the landfill limits access to the site. LUCs are in place for the site to prohibit groundwater use, maintain the engineered landfill cover, and prohibit the disturbance of soil on the site. The remedy in place continues to be protective of human health and the environment.
Six groundwater monitoring wells were installed in their current configuration around the perimeter of the landfill. Groundwater beneath the landfill is impacted by semi-volatile organic compounds (SVOCs), herbicides, and several metals and inorganics at concentrations exceeding regulatory criteria. Annual groundwater monitoring is being conducted at the site.
These are the previous investigations that have been conducted: IAS; and other miscellaneous Investigations.
LUCs have been implemented, and Long-term Groundwater Monitoring is being conducted.