Contact: sourcetostream@trca.ca

2024 Track 2 Day 1: Dion Stuart

TRACK 2, DAY 1

Naturalization of the Don River Mouth: A Component of the Port Lands Flood Protection Project, Toronto, ON

Tuesday March 26, 2024 | 9:00 to 10:00 a.m. | Hall F

ABSTRACT

Between 1912 and the early 1920s, the Toronto Harbour Commissioners (now Ports Toronto) undertook a major land reclamation project to infill the Ashbridge’s Bay Coastal wetland to create a large, low-lying ports industrial area.

As part of the project, a new navigation channel (Keating Channel) was constructed to divert flows from the Don River, westward into the Toronto Inner Harbour. Upon completion, annual dredging of the Channel was required to prevent it from filling with sediment from the Don River upstream.

During the intervening years, a wide-range of industrial activities followed on these constructed flood vulnerable lands, creating contaminated soils and groundwater, which further contribute to the near absence of functioning aquatic and terrestrial habitats.

Waterfront Toronto, with our partners from the City of Toronto and Toronto and Region Conservation Authority (TRCA), are currently constructing two new naturalized river outlets for the Don River, in addition to retaining the existing Keating Channel, as part of the broader-scoped Port Lands Flood Protection Project.

The river design will provide flood protection to 250ha of land in the broader Port Lands area (beyond a Hurricane Hazel-sized flood event), create or enhance up to 30ha of aquatic and terrestrial habitat, while addressing underlying contaminated soils and groundwater.

The form of the naturalized river mouth design is based on similar natural coastal wetlands in the Greater Toronto Area, while details of the channel and valley dimensions, and the spatial distribution of bed, bank and valley erosion protection are informed by the MIKE-21 2D hydraulic model.

A series of vertical and horizontal Risk Management Measures were developed to isolate the future naturalized river mouth from remaining soil and groundwater contaminants below and adjacent to the river. Dredging, previously undertaken in the Keating Channel will now be focused further upstream in the Lower Don, to ensure continued function of naturalized habitats and the requisite flood protection standards.

Our presentation will provide: a brief overview of the existing conditions observed in the Keating Channel and adjacent port industrial lands; outline the data collection, modeling and analysis used to develop the design for the naturalized river; present the resulting channel and valley form, features and ecological elements tied to our understanding the local estuarine hydraulics; summarize the techniques to isolate, treat and protect the resulting river mouth from remaining contaminants; and outline refinements to the existing dredging operations underway at the mouth of the Don River.

This project consolidates modern-day knowledge, tools and construction techniques from a wide-range of sciences, engineering and landscape design disciplines to create a large-scale transformation of the Don River Mouth.

This transformation will benefit the public and natural biological systems, address urban public health and safety issues (related to flood risk and exposures to contaminants), and provide the fiscal stimulus for intensified, sustainable revitalization in the broader Port Lands.

ABOUT THE PRESENTERS

Ken Dion

Ken Dion, Waterfront Toronto

Kenneth Dion is the Project Director for Port Lands Integration at Waterfront Toronto. He has worked on southern Ontario rivers, wetlands and shorelines for over 20 years, with Ontario Streams, Toronto and Region Conservation Authority (TRCA), and Waterfront Toronto.

Ken has participated in the Port Lands Flood Protection (PLFP) project since 2002 – first leading the initial Environmental Assessments with TRCA, and participating in the Due Diligence, and subsequent design and construction.

Ken joined Waterfront Toronto in 2018, and provides technical and planning support, facilitates collaboration and engagement, and more recently, oversees Project asset and real estate hand-overs at Waterfront Toronto.

Netami Stuart

Netami Stuart, Waterfront Toronto

Netami Stuart is Senior Project Manager, Parks for the Port Lands Flood Protection Project at Waterfront Toronto.

Both professionally and as a volunteer, Netami has made urban ecology and Toronto’s public parks her passion for over 20 years. As a landscape architect and arborist, Netami weaves living systems, design thinking, and delight into her work in Toronto’s public sector.

Previous to Waterfront Toronto, Netami worked for City of Toronto, PMA Landscape Architects, Ecoplans, Evergreen, and Urban Forest Associates. Supporting the integration of design and stewardship, Netami represents the Ontario Association of Landscape Architects on the Board of the Ontario Parks Association.