The frequency and intensity of catastrophic flooding in the wake of hurricanes and other natural disasters are increasing, and the impacts on cities and their inhabitants can be devastating. Rising waters in Prairie cities like Calgary and Winnipeg, and record-breaking rains in Eastern Canada’s largest cities like Toronto and Montreal, have led to declared states of emergency, mass evacuations and billions of dollars in damages.

Such frequent and destructive weather events, combined with an aging infrastructure network, are straining water infrastructure in major cities across North America. According to Catastrophe Risk Evaluation and Standardizing Target Accumulations (CRESTA), flooding across the US accounted for 78% of the total industry losses in 2024, making it "the year of the floods." A 2022 report from Canada’s Core Public Infrastructure Survey, which measures the stock, condition and performance of public infrastructure across Canada every two years, found nearly one in five kilometers of water, sewer and stormwater pipes were reaching the end of their useful life.

For years, PCL has partnered with local governments to build, repair or replace more than 50 water control and flood mitigation infrastructure systems that can withstand the increased anticipated burden on the system. Since PCL has honed an expertise in building water management infrastructure over decades, it has become a trusted partner to take on the complex task of increasing municipality flood prevention efforts through pipeline infrastructure upgrades and flood mitigation infrastructure improvements.

PCL was recently selected by Waterfront Toronto to deliver the third and final phase of flood protection efforts relating to the Don River: The Broadview and Eastern Flood Protection (BEFP) project, which is funded by three levels of government. Waterfront Toronto contracted PCL to build a flood protection landform (FPL) — essentially a large berm — along the Don River south of Eastern Avenue. This FPL protects land immediately north of the railway corridor on the east side of the Don River, and parts of South Riverdale south and east of the rail corridor.

Engaged early in the design process as construction manager, PCL Toronto’s civil team worked alongside the client and designer in the critical preconstruction stage of the project, exploring ways to optimize the design and constructability of a significant FPL through the solution-provider lens PCL brings to every project. Sharing sequencing plans, virtual modeling and real-time budget updates through PCL’s proprietary technology provided the client with a clear, up-to-the-minute vision of the schedule, potential risks and project costs.

PCL Superintendent Lawrence D’Andrea playfully describes the project in its simplest terms as, “Digging a hole, filling it with clay, and then covering it with grass.” However, the related complexities are not for the faint of heart, involving extensive utility relocation and expansion, including storm and sanitary sewers, building demolition, road reconstruction and removing a decommissioned bridge. Further, the team must contend with adjacent construction projects, land expropriation sensitivities, schedule impacts and non-negotiable deadlines from the upcoming FIFA World Cup 26TM, and a highly constrained work area that ties into a commuter train line and the DVP.

“Our team has demonstrated a solution-provider mentality throughout this project,” adds D’Andrea. “We’ve found ways to overcome complex obstacles with meaningful solutions that also provide value to our client.”

PCL’s ingenuity was on display with the demolition of the old Eastern Avenue bridge. The low-lying truss bridge, which hadn’t been used in 60 years, was an impediment to flood waters and at risk of full collapse. Bordered by the DVP to the east and an active rail line to the west, staging demolition from either shore was not an option. Solution? Demolition work on a floating barge.

PCL and its demolition partner positioned a barge in the Don River. That water work necessitated coordination with the Toronto and Region Conservation Authority and integration with environmental protection plans and flood protection emergency response plans to ensure everyone’s safety. One factor the team could not control was the weather. D’Andrea kept an eye on the forecasts to ensure the barge wasn’t at risk of being swept downstream in a flash flood. The team worked in shifts for 22 hours a day to expedite the demolition work.  

PCL Toronto’s civil team sought continuous value engineering opportunities to deliver added value to the project. Working with Waterfront Toronto and its design team, they identified a cost-saving measure related to the main sanitary feed out of the city. The 1.6-meter-diameter pipe, buried deep underground, runs along the same stretch where PCL crews are doing flood mitigation work. Crews will insert an epoxy lining to create a new protective barrier inside the pipe, avoiding expensive digging or replacing, and giving the pipe a 100-year lease on life.

The project’s early successes are rooted in the collaborative approach of the parties involved. “The client is very knowledgeable when it comes to construction practices,” says D’Andrea. “They understand what we are trying to accomplish and are supportive when we propose alternatives. It has been a pleasure working with them to transform Toronto’s waterfront.”

Flood protection work east of the Don River is expected to continue until 2027.

PCL is also putting its expertise in climate-resilient infrastructure to work in Calgary, where the city continues its efforts to mitigate the extreme impacts from the 2013 floods that led to more than $6 billion in damages and 100,000 evacuations. Since that time, with the support of the Government of Alberta, more than $150 million has been invested in flood mitigation and resilience projects throughout Calgary.

One such project, completed in 2018, involved the Wilder Institute/Calgary Zoo, which sits on St. George’s Island in the middle of the Bow River. The flood inundated the zoo grounds with devastating consequences that captured media attention when two hippos, named Sparky and Lobi, swam into a public viewing area and nearly escaped through a broken window.

PCL played a crucial role in future-proofing the zoo by installing a watertight seal around the island. The flood mitigation work was completed within an extremely small footprint to ensure minimal disruptions to zoo visitors and neighbors.

In 2023, the City of Calgary brought PCL on as construction manager for the Sunnyside Flood Barrier project. The multiyear project has undergone early design changes as planners aim to find the balance between protecting low-lying communities along the Bow River while preserving and creating spaces that connect the community to the water.

One of the challenges for designers was creating a flood wall that helps control seepage during a flood event but also maintains the normal groundwater outflow to the river from the subsurface aquifers. 

As part of the first stage of construction work, PCL’s civil team undertook a deep excavation to install a pressure relief system along Memorial Drive. PCL Project Manager David Ediger describes it as “640 lineal meters of giant weeping tile that will help mitigate groundwater pressure impacts during a flood event on the future flood barrier.” 

Seizing the opportunity to get ahead of the 2025 construction season, the PCL Calgary team also worked on small sections of the flood barrier itself, installing 100 cast-in-place concrete piles and sections of sheet pile flood wall along Memorial Drive, which runs adjacent to the river. The permanent metal wall, embedded meters underground, is designed to hold back flood water while minimizing disturbances to the natural environment.

Mitigating the noise and vibration impacts from construction is another challenge, as is limiting public access to nearby paths and roadways. “The impacts are felt by pedestrians, commuters and residents,” says Ediger. “Our team goes to great lengths sequencing the work to keep public spaces accessible for as long as possible and minimize road closures where possible.”

Coordination with The City of Calgary is a key component of the project. “It’s a priority for The City to minimize impacts as well, but also to communicate those impacts as soon as they can to provide Calgarians with the information they need.”

Whether it’s future-proofing critical infrastructure for climate resilience work or preventing the escape of curious hippos, PCL remains at the forefront of transformative infrastructure projects to support and safeguard our communities.

Photo (top) source: Reuters.