In October 2018, Nichols Environmental responded to an 18,000-L spill of asphalt flux (roofing tar) after two trailers detached from a haul truck along the off-ramp of Anthony Henday Drive onto Calgary Trail south. The hot tar flowed down the embankment, over a concrete retaining wall, and into a storm sewer catch basin that serviced the interchange.
Challenges for this project included a busy roadway and time restrictions, the presence of engineered fill, a retaining wall, and 275 m of affected storm line (1,000 mm in diameter). Approximately 80 m3 of impacted surface soils were removed mechanically and by hand from the embankment, and tar was removed via steam units and manually. Water samples collected at the downgradient stormwater pond indicated that no surface water had been impacted. The only remaining work to be completed in the spring of 2019 is removal of the tar from the retaining wall and hydroseeding of the remediated area.