Waterfront Toronto River Channel Risk Management Design and Construction Support
« All Projects

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 that has a budget of over $1.25 billion.

This project is an excellent example of collaboration 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 opportunities for improvement in the existing design related to reduced environmental and constructability risks.

Geosyntec’s Scope of Services

Based on our excellence in a peer review role, we were transitioned into the role of lead Design Engineer for the river channel environmental barriers installed as an RMM. 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 testing 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 and park features 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's role in this massive project and innovative thinking resulted in numerous benefits to our client including:

• We were able of step into the lead designer role for the river valley work part way through the project and under intense time pressures rethink the design to prepare design documents allowing the environmental RMM design to stay on schedule.
• Our understanding of the holistic design concept allowed us to limit soil disposal by using impacted materials from multiple areas of the Site as fill in other areas, such as in the surrounding river valley parks, roadways, or embankments of the future river valley.
• We continuously incorporated value engineering practices into the geotechnical design that have contributed to over $10 million in construction cost optimizations.
• We developed a dewatering tracking tool that was vital in managing all of the construction dewatering volumes to remain within the capacity limits of the on-site water treatment plant.
• Through a collaborative approach to the river channel design, we have facilitated a seamless working relationship with MVVA, Waterfront Toronto, the site construction manager, and other design team consultants, allowing for the continued early identification of cost effective design alternative optimizations and potential challenges and an expanding role on the project.

Geosyntec’s management team continues to support meetings 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 assist with the permitting and design review process, to yield value engineering opportunities from the approved design and reduction of construction costs and schedule.