It all began with the appearance of a tar-like substance in a prized Sarnia, Ont. waterfront park that was once home to Bayfest, a popular summer music festival that drew people from across southwestern Ontario and Michigan.
This summer, after five years of planning and implementing remediation and reconstruction, Centennial Park reopens in full.
The saga began in June 2012 when the material seeped from the ground throughout the 30-acre park. Located south of the Blue Water Bridge international crossing on Sarnia Bay near the mouth of the St. Clair River, Centennial Park opened in 1967, established on land that had at one time been home to two sawmills and a salt mine and was created largely from industrial fill.
At first, the city covered the affected areas and fenced them off until the strange goo could be identified. Bayfest went ahead. It would be the festival’s last event in the park for reasons unrelated to the contamination.
By September 2013 the city had its answer when engineering consultant Golder Associates handed in a report that documented contaminants at different concentrations and depths, including the topsoil.
Tina Marano, Golder’s director of marketing declined an interview, noting the company’s terms of agreement with its client do not permit comment to the media.
"The big one that caught us right off the hop was the asbestos that was found in the topsoil," says Andre Morin, a City of Sarnia engineer. Also found were materials such as lead and hydrocarbons.
The asbestos was worrisome. Sarnia has had high rates of asbestos-related disease compared to other communities in Canada.
City of Sarnia
Knowing the issue was explosive, city staff didn’t relish having to explain to council a plan to handle the contaminated soil within the site, Morin says. Removal of affected soils would have cost $30 to $40 million.
The park had been shut down in 2013 to conduct environmental assessments and develop a strategy to manage remediation. The cancellation of a legacy project in the park generated more community disappointment.
In June 2014, the city forged ahead with a three-year $6-million remediation action plan, hiring London-based Bre-Ex Construction Inc. to work on the first of three phases. The company was subsequently hired to conduct the final phases of remediation and reconstruction.
A Bre-Ex spokesperson did not respond to a request for an interview.
The first phase involved remediating green space to provide public access as soon as possible. To do so, Bre-Ex stripped topsoil and moved it into berms or added to existing berms to make them higher.
Next came a geotextile fabric and, on top of that, a half-metre barrier application of sand and clay. About six inches of clean topsoil formed the final layer and was seeded.
Morin says the geotextile barrier’s main purpose is to alert future generations to the contaminated materials below.
"We’re going to have O&M (operations and maintenance) manuals in place and our parks and recreation staff will be well aware that there are certain measures if they are doing any work in that park," he says.
Joe Boothe, city superintendent of environmental services, says perimeter air monitoring took place during remediation. If the wind picked up beyond a certain point work stopped and the crew wetted the material to ensure nothing became airborne.
In 2015, after another environmental assessment was completed, the city combined the second and third phases.
One of the main projects during the final phases has been moving the park’s two-bay boat launch next to the nearby city-owned marina.
Morin says creating space to store the contaminated materials onsite is one of the reasons why they must move the launch. They needed an area to locate material that was out of the way of sections of the park that had already been cleared.
They had also found contamination in sediment under water near the existing boat launch. Any dredging to clear that part of the bay would have presented more contamination issues.
The final phases, begun in 2016, involved a lengthy to-do list. Contaminated soil needed to be removed and contained. Much of this ended up in a new, shaped berm on the former boat launch parking lot.
As well, they needed to build a seawall to contain the site, upgrade a service building to meet new accessibility standards, add a new fully accessible playground as well as a healing garden, double the outdoor stage area and add a new promenade and lighting.
Moving a major watermain that ran through the middle of the park to a clean area beyond the park’s northern boundary became another priority to ensure if a leak ever occurred it wouldn’t result in a new contamination event, Boothe says.
The fall of 2016 had been the target date for completion but as work progressed it became evident problems with building the new boat ramp would create a major delay.
Sediment instability was foiling attempts to erect cofferdams to drain the new boat launch area of water so construction could take place.
The areas of less stable soil had appeared between areas sampled during the initial geotechnical investigation of the area. The survey samples hadn’t revealed any issues.
Bre-Ex "tried three different times with the cofferdams, different technologies, and they’ve encountered problems with the sediment, the type and the quality that were totally unexpected," Morin says.
Consultants are engineering a solution. In the meantime, however, city staff pushed project deadlines to late spring.
Even those dates could be subject to change depending on weather, Morin says.
The delays and challenges have drawn criticism from some corners of the handling and expense of the $11 million project. The studies cost $3 million and the remaining amount covers remediation and reconstruction of the park’s facilities.
The city engineer and environmental services superintendent defend the project’s handling.
"We’ve basically done all the environmental studies, all the engineering work and completed all the construction within five years," says Boothe.
Normally, just obtaining the environmental studies and approval to proceed with a brownfield development can take three to five years, he notes. Big capital projects always face unknowns, says Morin.
"You end up finding things in the ground that you didn’t realize or you find a problem that you didn’t think you’d actually encounter, and that’s unfortunately what we’ve had on this project," he adds.
Communication has helped, they say, as has a good collaborative process with the provincial and federal government departments involved.
Gary Wheeler, a spokesperson for the Ontario Ministry of the Environment and Climate Change, says by email the city and Golder worked with the Ministry of Labour to develop site-specific standard operating procedures to deal with asbestos contaminated soil.
"The procedures were developed to protect workers at the site and the public," he says.
The environment ministry acted as a resource to the city during remediation and is "supportive and satisfied with the city’s remediation of the park."
Morin and Boothe say they may face similar challenges in other city parks in the future. They’ve learned many lessons from Centennial Park, including the importance in a long-term project of compiling detailed documents to keep people up to date and maintain continuity.
"We as staff see it (the Centennial Park project) as a huge positive," says Morin. "It’s actually a really successful story" that will be "a pretty stellar park when we’re all said and done."