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Brown’s Lake Remediation

Fort Eustis, Virginia



United States Army


Malcolm Pirnie




September 2008

Technical Description:

Vortechs Hydrodynamic Separator

Occupying approximately 8,300 acres in southeastern Virginia, Fort Eustis, owned and operated by the United States Army, began operations as a training center (known as Camp Abraham Eustis) in 1918. Over the years, it has served both military and nonmilitary functions, and today is a U.S. Army Transportation Training Center with approximately 17,500 military personnel, their dependents, and civilians living or working there.

In 1988, the U.S. Army Toxic and Hazardous Materials Agency identified multiple potential waste sources at Fort Eustis, and the site was formally added to the National Priorities List (NPL) as part of the Superfund program in 1994. One of the sites identified within Fort Eustis was Brown’s Lake, a man-made lake that receives runoff from helicopter and locomotive maintenance areas.

Once a popular fishing spot, Brown’s Lake was closed in the late 1970s by the Fort Eustis Preventive Medicine Group because of contamination. Throughout the 80’s and 90’s, water quality tests continued to show high levels of pollutants, including polychlorinated biphenyls (PCBs), pesticides and polycyclic aromatic hydrocarbons (PAHs) in the lake as well as downstream tributaries. In the late 90’s, action was taken to both remove contamination as well as to prevent future releases from the surrounding industrial area, but the lake remained off-limits to fishing.

Remediation was taken a step further in 2007, when a clean-up effort began on the upper drainage ditch leading to Brown’s Lake. During storms, stormwater runoff from the 50 acre drainage area would collect in the ditch and then discharge into Brown’s Lake. Project engineers were tasked with removing pollutants, especially PAHs, from the stormwater prior to entering into the lake.

Working with Contech, project engineers designed a way to dam the ditch and treat stormwater before it reached the lake. A 20-ft concrete weir wall was installed across the ditch to route storm flows up to 70 cfs into a 20-ft x 30-ft Vortechs system. The system was castin- place on-site. The Vortechs system, from Contech, is a hydrodynamic separator designed to maximize the settling properties of particulate pollutants. In addition to trapping coarse solids, the multi-chamber design also traps free oil and grease and floatables such as trash and debris. The system is most effective at removing particulate pollutants and contaminants bound to particulates, so the PAHs removed would be bound to sediment 50 microns and larger.

Maintenance of the system is easily done with unobstructed access to sequestered pollutants in the system’s swirl chamber. Periodic removal of pollutants will ensure that the Vortechs system will continue to perform as designed and help protect water quality.

In the Spring of 2017, in conjunction with the Virginia Department of Environmental Quality and Environmental Protection Agency, the installation had successfully reached a point where the lake could be reopened for catch and release fishing.

Technical Description:

Vortechs Hydrodynamic Separator


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