Oak Ridge Finishes First Groundwater Monitoring Phase for New Disposal Facility

An aerial view of the Environmental Management Disposal Facility project footprint. Crews installed a 1.3 million-square-foot geomembrane layer that simulates the effect of lined disposal cells on groundwater elevations, creating an impermeable barrier over the site. The turf, much like grass, slows the flow of stormwater, providing improved stormwater controls. The final layer, sand infill, weighs down the turf and prevents damage from strong winds.

OAK RIDGE, Tenn. – The Oak Ridge Office of Environmental Management (OREM) and contractor UCOR completed an essential step to prepare for construction of a new onsite disposal facility: groundwater monitoring during the first of two wet seasons.

The Environmental Management Disposal Facility (EMDF) will provide the waste disposal capacity needed to continue OREM’s large scale cleanup projects at the Y-12 National Security Complex and Oak Ridge National Laboratory.

Monitoring groundwater levels is part of a groundwater field demonstration study. This work allows OREM and UCOR to gather information about how groundwater elevations change, providing valuable information for the landfill’s final design.

Gathering data during the wet seasons is important because that's when groundwater levels are highest. There is more rain, and plants without foliage absorb less water. In east Tennessee, the wet season typically runs from December through March.

Worker installed more than 1,800 feet of waterline to the Environmental Management Disposal Facility site. These utilities will support future construction activities and operations for the disposal facility.

Prior to the start of monitoring, workers installed an impermeable geomembrane over an approximately 1.3 million square-foot area, simulating the effect the disposal facility liner system will have on groundwater elevations.

Results from the first wet season showed groundwater elevations steadily declined over this first wet season by preventing precipitation from infiltrating the future EMDF disposal cell area.

“This first groundwater monitoring season successfully demonstrated that groundwater elevations will be lower under the EMDF disposal cells following construction,” UCOR EMDF Project Manager Mary Magleby said. “We’ll use what we learned from wet season monitoring to inform the design and ensure the disposal cell liner system meets requirements.”

Groundwater elevation monitoring is a requirement listed in the project’s record of decision approved by the U.S. Department of Energy, U.S. Environmental Protection Agency and Tennessee Department of Environment and Conservation.

The team, which includes subcontractor CTI, also finished installing utilities at the site to support future EMDF construction activities and operations.

The utility extensions will provide the EMDF site with water and power. Workers installed more than 1,800 feet of waterline and more than 1,300 feet of electrical power line, and they removed roughly 2 miles of previously abandoned power line from the project footprint.

Groundwater elevation monitoring will continue for a second wet season from this December through March next year to provide the data necessary to finalize the facility’s design before construction begins.

-Contributor: Ella Stewart