In June 2013, over three days, approximately 10 inches of rain fell on the Town of Canmore, Alberta, situated on the eastern slope of the Canadian Rockies. Combined with the melting spring snowpack, the sudden surge of water rushing down Cougar Creek led to catastrophic flooding. The event caused significant damage, forced the evacuation of 1,200 residents, and exposed the need for robust flood mitigation measures to protect the community and critical infrastructure from similar disasters.

In response, planning for the Cougar Creek Debris Flood Retention Structure began shortly after the flood, culminating in an ambitious project that would take nearly a decade to realize. Construction of the structure began in 2020, designed to withstand 300 to 1,000-year flood events.

The Cougar Creek Embankment Dam is a 34-meter-high rock-filled structure strategically located where Cougar Creek exits the mountains. In normal conditions, water flows freely through an outlet at the base. During flood conditions, the structure controls the flow of water, capturing up to 650,000 cubic meters of sediment, boulders, and debris, preventing downstream devastation to homes, businesses, and transportation infrastructure. Built for durability and longevity, the dam's construction involved excavating the creek-bed alluvium to bedrock, installing a concrete plinth foundation, and erecting interlocking steel sheet piles embedded in concrete. The abutment piles on either side of the canyon were placed in 1.5-meter-deep trenches and sealed with SWELLSEAL®, a hydrophilic polyurethane, and Polyguard 610, a rubberized coating system. Finally, the structure was backfilled with rockfill to complete the embankment.

A key component of the project’s success and longevity is the use of hot-dip galvanizing (HDG) to protect the steel components which provide the primary structural support of the dam. Exposed to harsh conditions, including moisture, sediment, and dramatic seasonal temperature fluctuations, the steel sheet piles and critical structural elements required a solution that would withstand corrosion and ensure long-term performance. Hot-dip galvanizing provided an ideal protective coating, offering exceptional durability, low maintenance, and a life expectancy of over 100 years in similar environments. The zinc coating from HDG forms a metallurgical bond with the steel, creating a tough barrier resistant to abrasion and chemical wear—critical for a structure that will endure significant debris loads and water pressure during extreme flood events.

Felix Camire, project manager for the Town of Canmore, emphasized the importance of material durability, saying, “Galvanizing of the steel sheet-piling was chosen to significantly increase the lifespan of the sheet-piles. Rehabilitation of such a large embankment structure is very complicated and expensive; therefore, ensuring that our seal wall lifespan is as long as possible is critical.”

In 2024, the Cougar Creek Debris Flood Retention Structure reached completion, marking a significant milestone for the Town of Canmore. According to Andy Esarte, the Town of Canmore’s manager of engineering, the structure has a service life of approximately 200 years, with only periodic maintenance required to ensure its long-term performance.