Redeveloping a former landfill site with park amenities has meant extra digging for solid foundations.
At Harbourview Park, crews have been installing water services for the future water play infrastructure, and the soft ground covering a former landfill has added some costs.
The potential for those added costs was anticipated as extensive testing of the site confirmed the ground as-is couldn’t offer structural support.
The town’s director of parks, recreation, and culture, Dean Collver, said there was excavated material taken away to the landfill on Tenth Line at a total cost of about $3,000 (including trucking).
The material taken away included soil, peat, and former non-hazardous landfill waste such as glass and strips of tarpaulin.
Removing the materials was part of the excavation work necessary to bring water and wastewater services to the site. Crews determined it would be more structurally sound to add clean fill instead of refilling the hole with the excavated material.
The makeup of the soil at the water play site was no surprise to Collver.
Harbourview Park is the site of a closed landfill. The site was cleaned when it was closed and materials that would be considered hazardous and/or create off-gasses like methane were removed.
Inorganic materials such as hose, carpet and glass remain buried at the site and covered with topsoil.
“The whole space was a landfill at one point. We knew it before discussing the gathering place as an option in the waterfront master plan,” said Collver. “We were aware it needed to be addressed properly from day one.”
Part of ‘addressing it properly’ included obtaining a certificate issued by the Ministry of the Environment confirming there’s zero potential for leaching or off-gassing from what waste remains buried at the site.
The certificate condones park use including the existing soccer fields, the Awen Gathering Circle, and the future water play facility.
The town had a D-4 study done on the site and on adjacent lands, which is a comprehensive review used for former landfills and adjacent lands to determine the impact of development on the land and identify potential hazards. The D-4 done on Harbourview Park did not identify hazards, and cleared it for development.
The certificate and D-4 study, according to Collver, provides a basis for the town to understand how it can repurpose the land.
Geo testing and extra soil analysis done prior to the water play park project confirmed pile foundations would be required as was the case for the Awen Gathering Circle.
When the town was building the Awen feature, David Wood, an engineer from Envision Tatham, explained the former landfill site means the ground has no “structural bearing capacity.”
“The structural engineers could not give it a value … it might as well have been popcorn,” said Wood during a council meeting in Nov. 2019.
Piles driven into the bedrock under the landfill materials served as a foundation for the Awen circle, and the same approach will be taken for the water play area currently in the works.
The Awen circle was three per cent over budget (about $21,000).
“We fully expected pile foundations would be required [for the water park],” said Collver. “Even regardless of any waste material still remaining there, the ground contains a large amount of peat.”
In addition to the $3,000 to truck away excavated material, the project has also required about $11,500 worth of upgrades to the existing water service pipes to increase the size from 100 mm to 150 mm.
Though that amounts to about $15,000 in previously unbudgeted costs, it’s about one per cent of the $1.5 million budget for the water play park.
Collver said there are many components to the water park, and opportunities to find efficiencies.
“Relative to the overall budget, I’m feeling comfortable at this time with lots of work and lots of tendering left to do,” said Collver. “We will move cautiously to do everything we can to stay inside our budget cap.”
With servicing now installed, the town is working to finalize tender documents for the technical design of the water supply and recycling system. A separate contract for the parking area will be awarded soon.
