Waterfront Toronto River Channel Risk Management Design and Construction Support
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A clear example of our capabilities in transforming highly contaminated former industrial waterfront properties into a livable community with improved uses is our experience with the over 700-acre Waterfront Toronto redevelopment project.

This project is an excellent example of being collaborative with the client and with the landscape architect, Michael Van Valkenburg Associates (MVVA). Geosyntec's initial scope of work was with MVVA’s client, Waterfront Toronto, to provide a third party technical review of the long-term environmental risk management measures (RMMs) associated with the river channel and designed to address potential mobile non-aqueous phase liquid (NAPL), residual NAPL, and dissolved phase NAPL. Our critical technical and strategic review identified many shortcomings in the existing design including continued environmental and constructability risks.

Geosyntec’s Scope of Services

Based on our excellent in a peer review role, we were transitioned into the role of lead Design Engineer for the risk management measures (RMMs) river channel. Our integrated approach to RMMs design and our geotechnical design experience identified methods for re-use and containment of contaminated materials on site, efficiencies in construction, and design optimizations that resulted in substantial cost savings. This demonstration of our capabilities resulted in us becoming a fully integrated member of the project team. Our design and RMMs have been discussed, challenged and ultimately accepted by the applicable regulatory agencies.

The project includes the excavation of a new outlet river channel connecting the Don River to Lake Ontario, to alleviate upstream flooding and provide new wetlands and park assets for the City of Toronto. A key objective of the project has been to develop a design that can be integrated with other aspects of the Port Lands redevelopment including, but not limited to, civil construction, utilities, earthworks and soil reuse, river finishes, and parks.

As Design Engineer for the RMMs, consisting of a vertical secant and slurry cutoff wall and horizontal barrier along the base of the new river channel, Geosyntec has i) developed 100% construction drawings, specifications, and bid forms; ii) constructed a groundwater flow model to assess the potential impact of pre- and post-construction groundwater flow conditions; iii) performed site-specific NAPL sorption and isotherm tes ting to optimize design parameters and barrier material selection, iv) conducted seepage analysis to estimate dewatering rates and optimize cutoff wall depths; v) conducted geotechnical analysis to assess global and internal stability of the RMMs during and post construction, as well as shallow and deep foundation designs for supporting bridges; vi) developed an online information management system for the automated tracking and reporting of the RMM construction process; and vii) filled the role of resident site inspector for the installation of the cutoff wall.

Geosyntec's continued collaborative approach to the river channel design has facilitated a solid working relationship with MVVA, their client Waterfront Toronto, the site construction manager, and other design team consultants, allowing the continued early identification of design alternative optimizations and potential challenges, while meeting strict design deliverable deadlines for this game-changing project.

Notable Accomplishments

Geosyntec role in this massive project and innovative thinking resulted in numerous benefits to our client including:

  • Our understanding of development plans early in the process allowed us to limit soil disposal by using impacted materials from multiple areas of the Site as fill in consolidation areas, such as underneath buildings, paved areas/roadways, or embankments of a future marina.
  • We created a data management system for disposal records which integrated hazardous waste tracking information/records from multiple vendors, areas of the site and tasks. This managed documents better which limited our Client’s exposure to waste handling violations.
  • We led the pre-construction/permitting environmental investigation for soil and groundwater which was incorporated into environmental planning documents. This allows these to serve as pre-approvals for waste disposition and aided in developing subareas of targeted impacts to maximize trucking efficiency.
  • We maintain a critical communication stream between the project owner, general contractor, on-site subcontractors, and owner’s waste management vendor and other consultants. This facilitates smoother construction with minimal delay especially those caused by waste handling or management.
  • Through existing relationships with regulators and waste disposal facility operators in the region and engaging in a competitive bidding process, we identified a cost-effective reuse/recycling and disposal alternative for materials such as cinder ballast, railroad ties and petroleum-impacted soil.

Geosyntec’s management team continues to meet regularly with project stakeholders including the City of Toronto, Toronto Region Conservation Authority (TRCA), Ministry of the Environment, Conservation and Parks (MECP), Environment Canada, Construction Manager (EllisDon) and other design consultants to gain consensus on key design assumptions and project decisions, reduce design iterations, and assisted with the permitting and design review process, which resulted in value engineering opportunities from the approved design and reduction of construction costs and schedule.

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Project Summary

  • Location: Ontario, Canada
  • Client: Michael Van Valkenburgh Associates Inc.
  • Project Practice Areas: Environmental Management, Geotechnical
  • Type of Facility: Park
  • Services Provided: Design basis for river channel environmental risk management measures, Design-build specifications, calculation packages, and issue for construction drawings for river channel construction RFP, Technical resident site inspector support for river channel risk management measure construction
  • Type of Work: Design
  • Governing Regulation: State and Local