WEB EXCLUSIVE: From brownfield to Pan Am athletes’ village: Reclaiming Toronto’s West Don Lands

Repurposing the former brownfield for mixed-use development involved one of the largest environmental risk assessments ever undertaken in Canada, a range of remediation techniques—all within a timeline that had been cut in half.

A history of neglect

From the 1830s to the mid-1900s, the West Don Lands operated as a thriving industrial port, crowded with pork packers, soap-makers, leather tanneries, a foundry, salvage and lumber yards and warehouses, as well as the tumble-down shacks that housed the (mostly Irish) labourers. Filler soil from the lake, construction sites and subway tunnels of Toronto had been dumped there to elevate the land and allow development.

But by the 1970s, de-industrialization had left the Don Lands largely deserted. Its industrial history meant the land was polluted by many different toxins. In 1988, the provincial government purchased the property, announcing a project called Ataratiri. The aim: to provide affordable housing for more than 10,000 people.

Three years later, the government had invested almost $300 million with little to show for it. And there was no end in sight to the bleeding; projections showed the plan would be $893 million over budget by 2001.

With environmental regulations then in their infancy, one of the factors contributing to the price tag was “the high cost of making the land suitable for residential use,” says Jesse Zuker, project manager of the Pan Am Athlete’s Village at Infrastructure Ontario (IO), the government entity developing the site in partnership with Waterfront Toronto.

Apart from the area’s industrial past, the imported fill used to build up the swampy land had come from all over Toronto. “There’s probably a million unknown sources for the material placed there,” adds Dave Hutchinson, an environmental specialist under secondment to IO, now with Mississauga, Ont.-based Conestoga-Rovers & Associates.

The result: a lot of low-level contaminants in varying concentrations across the site—specifically metals, petroleum hydrocarbons, poly-aromatic hyrdrocarbons, volatile organic compounds (VOCs) and PCBs.

According to the environmental regulations of the late 1980s, generic remediation was required; and that meant removing and transporting hundreds of thousands of tonnes of soil. But in 1992 Ataratiri was cancelled and the Don Lands were largely deserted. As of 2006, the census showed just five inhabitants on the entire 80-acre site.

“It was widely used for film shoots when they were looking for an industrial wasteland,” recalls Zuker. “They would digitally remove the CN Tower from the skyline so it could be any city.”

Risk assessment

Fast-forward to 2006. With Toronto in the midst of a building boom, the centrally-located Don Lands represented an opportunity for development. Ontario’s environmental regulations had evolved, allowing for a broader suite of ‘best practices’, according to Zuker. That made clean-up of the site a more affordable proposition.

Spearheaded by Waterfront Toronto, a new initiative was put forward to create a mixed use community with 6,000 housing units, retail and office space and 23 acres of public space.

The good news: Instead of treating the entire site as toxic—which meant digging and dumping 950,000 tonnes of soil—the team was able to use an environmental risk assessment to determine which contaminants were present and in what quantities.

It enabled them to remove only the soil with dangerous concentrations of toxins (about 16,000 tonnes), and then come up with strategies to incarcerate materials with lower levels of toxicity, removing them from contact with people or animals. The result: significant time and cost savings over generic remediation, says Hutchinson.

The West Don Lands risk assessments (RA) and record of site condition (RSC) were the first to be processed under the new regulations, says Krista Barfoot, a risk assessor for brownfield redevelopment at CH2M Hill, the company tasked with performing ESAs and RAs at the site. “We were charting unnavigated regulatory waters and a lot of care had to be taken to ensure we were meeting all the requirements.”

Investigators took more than 500 soil samples and almost 300 ground water samples, says Barfoot. Electromagnetic and ground penetrating radar helped locate buried metal objects (such as sumps, pits and underground tanks).

Barfoot admits the sheer size of the project made it a challenge. The situation became more complicated in 2009 when the government announced the West Don Lands would be home to the athlete’s village for the 2015 Pan American Games. All of a sudden, remediation deadlines were cut in half from 10 to 12 years, to just six.

CH2M Hill responded by parcelling out the assessment and risk management work to different teams and sub-teams, allowing “many aspects of the program to run concurrently,” says Barfoot. “A schedule was developed, stepping back from the critical end date so it was clear how much time was available for each interim task.”

The many stakeholders in the process—including Waterfront Toronto, Ontario Realty Corporation, the City of Toronto, Toronto & Region Conservation Authority, along with industry experts—committed to reviewing the work on an ongoing basis, rather than waiting until the process was over.

Working closely with the Ministry of the Environment (MOE), a team led by Infrastructure Ontario and CH2M Hill ultimately came up with “an approved site-specific list of suitable contaminant levels, as well as risk management measures to be implemented to ensure that humans and the environment are protected,” explains Zuker.

A suite of solutions

There was no single solution that could be counted on to deal with all of the West Don Land’s environmental issues, so the team deployed a number of different approaches. Among them:

A massive flood-protection barrier. Most Torontonians are blissfully unaware that the city’s financial district sits in the flood plain of the Don River, making it vulnerable to a catastrophic weather event such as 1954’s Hurricane Hazel. To make the West Don Lands project feasible, the team built a four-metre high berm along the Western bank of the Don River, capable of withstanding such a flood. They were able to use concrete rubble from the site, as well as excavated landfill and a top layer of clean soil to build the berm, which is now a park.

Dig and dump: About 16,000 tonnes of soil had to be dug up and removed from the site. Most was taken to area landfills.

Clean cap: Rather than dig up and remove all the contaminated soil, workers placed a clean layer on top at varying depths according to whether it was located below landscaping or asphalt. The clean cap is marked, says Zuker, “so that anyone who is digging in future knows that they may hit contaminated soil.” That soil is topped by either asphalt or grass to provide a further barrier.

Granular material barriers: Pipes and other underground structures are surrounded by a clean layer of granular materials so maintenance workers aren’t likely to encounter contaminated soil.

Vapour barriers: Workers will spray an impermeable membrane on building basements to control the environment and reduce the likelihood of gases penetrating from the soil.

A vapour collection system: Working on the same principal as weeping tiles, the piping system will vent soil g
ases to the open air, preventing them from migrating into the buildings.

Removal of buried oil tanks: About a dozen oil tanks had to be dug up and removed from the site – a fairly simple process.

The cost would be considerable; the work that was done before any buildings began to go up at the West Don Lands site set the government back about $304 million, including the risk assessment and remediation, as well as the flood protection barrier and a new storm water management system.

Still, it was far less than it would have been under the previous environmental rules, which would have required most of the soil to be dug up and dumped in landfills at tremendous cost.

Cranes now dot the once-deserted West Don Lands, and construction workers abound, galvanized around a schedule to build a neighbourhood that will house 10,000 athletes and officials for the Pan Am Games.

When it’s complete, the venue will feature its own transportation system, a dining hall to seat 5,000, welcome centre, medical clinic and temporary practice training facilities, including a running track and pool.

After the Games, the athlete’s village will be repurposed as a student residence for George Brown College and the athletic facility will be turned over to the lively, mixed-use community slated to rise around it.

But much of the work on the West Don Lands occurred long before the buildings began to rise, in the soupy, contaminated soil of the site.

“For most my lifetime I saw that land derelict,” says Toronto-bred Hutchinson. “That’s one of the reasons I got into this business: to make land like that usable again. It feels great to see the site being re-developed into a vibrant and well-planned community.”

Camilla Cornell is a Toronto-based environmental and business writer.

This article has been sponsored by ERIS, Canada’s trusted source of environmental land records for risk mitigation. For more information visit the ERIS web site