The U.S. Army Corps of Engineers (USACE) Louisville District spent three weeks working at the Raco Army Airfield and Missile site, conducting sampling and installing new monitoring wells in an effort to delineate a 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 (DoD)-related contamination on properties that were owned, leased, possessed or used by the Defense Department.
Louisville District environmental engineers Josh Van Bogaert and Brittney Hyde were present to oversee the fieldwork with contractor Geo Consultants, LLC. From Aug. 18 to Sept. 9, the project team installed 12 borings and five new monitoring wells up to 276 feet deep. More than 200 Volatile Organic Compound (VOC) samples were analyzed at an onsite mobile laboratory.
"The team executed a dynamic work plan extremely well," said Van Bogaert. "Working in very difficult hydrogeological conditions with heaving sands, we learned that the TCE plume is over 100 feet deeper and twice as long as previously known."
The first round of groundwater sampling from the new wells was completed on Oct. 2 with the next round to occur in spring 2015.
"Adverse winter weather prevents additional investigation this year. We are in the process of analyzing the data from this phase, so we can plan the next phase of investigation to take place in spring 2015," said Van Bogaert.
After all sampling is complete a remedial investigation report will be prepared to summarize the results of all the field efforts, describe the extent of the TCE plume and determine if there is any potential risk to human health and the environment. The report will be completed after all field work is finished.