Abstracts

and remediation performance in smear zones containing trapped air that are made using
existing two-phase correlation models could be misleading.
156 - Nature, Nurture and Sustainable Remediation: Case Study
From a Major Hydrocarbon Release in a Sensitive Urban Riverine
Environment
K.J. O’Shea, Tiana Robinson, Nathaniel Novosad, Karen Wright, Tereza Dan &
Ulysses Klee
Stantec Consulting Limited, Stoney Creek, Ontario, Canada
Long-term, sustainable remedial solutions are often overlooked following a high-profile
spill. Instead, there is a drive to fix the issue immediately, and remedial plans are often put
into place without a sufficient understanding of subsurface conditions or consideration
of other natural features. The rush to a solution can cause significant additional harm to
the environment during implementation. This talk presents a case study of a hydrocarbon
spill in a sensitive riverine environment, and describes how nurturing naturally occurring
processes utilizing the physical characteristics of the site can result in an elegant and sustainable
solution to a complex remedial problem.
In 2010 a pipeline release of approximately 90,000 litres of petroleum hydrocarbons (PHC)
occurred in a creek valley outside a major urban center in Ontario. The affected area was
nearly 3.5 acres. The site is classified as an area of natural and scientific interest, is part of
provincially significant wetland complex, is considered environmentally sensitive, and has a
well-developed tree canopy. The site is home to wildlife such as by wild turkey, deer, beaver,
and snapping turtles, and the creek is a popular recreational fishing area.
From the time of the release, there was significant pressure from various interested parties to
implement a full scale “dig and dump” strategy to manage the impacts at the site. If implemented,
this would have resulted in complete removal of the vegetation at the site, as well as
all overburden materials and shallow bedrock in the excavated area. The complete devastation
of the biota, plus the slow recovery of the sensitive environment to current conditions would
takes years. During the yearlong excavation program, significant construction traffic to local
neighborhoods, and considerable costs, would be incurred. All stakeholders eventually recognized
that while the dig and dump approach was viscerally satisfying, it was not practical or
appropriate, given the relative health of the vegetation and wildlife in the affected area. Stantec
completed additional site investigation and characterization activities, and developed a more
sustainable remedial strategy for the site that was still protective of human health and the environment
that also considered the social, economic, and environmental benefits of the approach.
Stantec’s proposed solution to address remaining impacts at the site is currently being
implemented, and was developed in consultation with the regulators and stakeholders. In
the end, a multi-prong approach was selected that included risk assessment, phytoremediation,
enhanced bioremediation and groundwater recovery. This solution will ultimately
minimize the impacts to neighbourhood residents, recreational site users, and vegetative
and wildlife communities.
60 IAH-CNC 2015 WATERLOO CONFERENCE