RCMP Carcross Detachment—Remediation of Petroleum Hydrocarbon Contamination
The regional detachment of the Royal Canadian Mounted Police is located in Carcross, Yukon, in the south Klondike region. Following the release of approximately 4,000 litres of heating oil from a fuel line connecting the detachment furnace to two above ground storage tanks in 2002, Hemmera was called in to firstly investigate the extent of the soil and groundwater impacts, and subsequently manage the remediation.
For many reasons, this was a challenging project requiring innovative solutions. Previous investigations for soil and groundwater found that contamination had migrated from the RCMP site to the neighbouring Yukon Territorial Government property. Prior to remediation, approximately 1,600 cubic metres of soil was estimated to be impacted to a depth of five metres, with the highest concentrations located directly beneath the detachment building. The aerial groundwater plume was measured, and light non-aqueous-phase liquids (LNAPL) estimated to cover an area of approximately 200 square metres.
To resolve the situation, Hemmera evaluated various remedial options, and provided a detailed remedial design for the chosen option. Essentially, the contaminated soils were removed via supporting the detachment building and excavating beneath with the detachment remaining operational. Hemmera provided technical specifications for the tendering process, and once the contract was awarded, acted owner’s representative on-site as well as the environmental consultant and lead for the geotechnical and structural design engineers.
As a result of the thorough remedial plan, the project was successful. Approximately 3,000 tonnes of unusable overburden and 1,500 tonnes of waste soil was excavated and transported off-site for disposal during the remedial program. Confirmatory soil sampling results indicated that the remaining soils met the PWGSC and RCMP remedial objectives for the project.