The U.S. Army Corps of Engineers Louisville District is back on site for the summer at the Raco Army Airfield and Missile Site conducting aquifer profiling and installing monitoring wells in an effort to delineate a half-mile long trichloroethene (TCE) groundwater plume.
The site, just southwest of Sault Ste. Marie, Michigan, in the Hiawatha National Forest was used as an airfield for 21 years and a missile base for 13 years, ending in 1972. Under the Formerly Used Defense Sites (FUDS) program, USACE cleans up Department of Defense-related contamination on properties that were owned, leased, possessed or used by the Defense Department.
Louisville District environmental engineers Josh Van Bogaert, Craig Coombs, Brittney Hyde and Quyet La and geologist Mark Nichter have been alternating 10-day shifts onsite to direct the fieldwork with the contractor, GEO Consultants. Since April 21, the project team has drilled over 3,600 feet, installed seven new monitoring wells up to 330 feet deep, and analyzed more than 259 Volatile Organic Compound (VOC) samples at an onsite mobile laboratory. Clarissa Murray and Steve England, from the Regional Center of Expertise for Groundwater Modeling in Philadelphia District, have been assisting with real-time 3D plume modeling.
“The exceptional coordination between the contractor, USACE field staff, USACE office staff, and state regulators has allowed us to deliver an efficient project for the FUDS program,” said Van Bogaert. “Through several field staff transitions, and despite working in a remote location in conditions ranging from snow to hot weather with biting black flies, the field work has continued to go smoothly.”
The first round of groundwater sampling from the new wells will take place mid-July with the next round to occur in late fall 2015. In addition to the on-site sampling, four nearby residential drinking water wells were sampled to ensure there were no detects of VOCs in the water. All of the residential well samples were clean.
“Sampling the residents’ wells was an extra precaution,” said Van Bogaert. “Ensuring their safety is our top priority, and it helps ease the minds of residents.”
After all field work is complete, a remedial investigation report will be prepared to summarize the results of all the field efforts, define the nature and extent of the TCE plume, describe contaminant fate and transport processes, and determine if there is any potential risk to human health and the environment.