Trihydro was initially contracted by Wyoming Department of Environmental Quality (WDEQ) to perform site inspection (SI) activities at three areas of concern (AOCs) at the Former Casper Army Air Field (FCAAF) site in Casper, Natrona County, Wyoming. When WDEQ received additional grant funding from the United States Environmental Protection Agency (USEPA), the contract was amended to provide additional investigation work. Trihydro performed investigative activities at 12 AOCs that include former landfills, firing berms, weapon storage, fuel distribution systems, flight line operations, facility operations, and fire practice areas.
Investigative activities included geophysical surveys, subsurface soil sampling, surface soil sampling, groundwater sampling, well installation and groundwater sampling, unexploded ordnance (UXO) surveys, and surface water and sediment sampling. Investigations of multiple AOCs were conducted during a single field effort when funding was available to minimize mobilization costs. Multiple field investigation efforts were undertaken as the result of additional funding on a yearly basis. Innovative use of field screening saved money and maximized investigative activities with available funding.
Investigations required constant coordination with airport personnel so as not to disrupt airport operations and to make sure that airport utility personnel were aware of work efforts. Work was coordinated with multiple subcontractors, including drilling and laboratory subcontractors, as well as additional state and federal agencies.
Trihydro prepared multiple work plans for the investigations and compiled the investigative results from the AOCs into an SI report for WDEQ. The report focused on the presence or absence of contamination, identifying Chemicals of Potential Concern (COPCs), identifying potential exposure pathways and receptors by developing a conceptual site model (CSM), and making recommendations for additional work phases based on SI data results.