The Canadian city of Calgary is building a 2.4 km-long steel flood barrier to protect its infrastructure and population.
As climate change worsens, Canadians will experience a significant increase in the frequency and intensity of flood events, warned the Canadian Climate Institute in its September 2024 factsheet. It stated: “Increasingly frequent and severe short-duration rainfall events increase the likelihood of flash floods, especially in urban areas, by overwhelming storm sewers and drainage systems.”
Consequently, densely populated coastal and river areas across the country are reassessing their flood defences and Calgary is taking the threat of flooding particularly seriously.
In a bid to avoid a repeat of the damage caused by the 2013 flood, where one person died and there was C$6 billion worth of financial and property damage, the city, in the province of Alberta, is building a 2.4 km-long flood barrier.
Known as the Sunnyside Flood Barrier, it is constructed from a mix of permanent flood walls and temporary deployable systems, such as sandbags and water-filled tubes, and demountable flood walls.
Sheet pile flood walls are best suited to built-up areas
A steel sheet pile flood wall forms about half the length of the flood barrier. This is because sheet pile is particularly well-suited to tight spaces and requires minimal removal of surrounding construction or trees. This permanent, interlocking sheet metal wall, designed to hold back flood water, is embedded three to six metres below ground to provide structural stability.
Ground vibrations during the installing of sheet piling can cause damage to nearby infrastructure, such as buried utilities, bridges or homes. To avoid this, vibration monitoring is ongoing during the sheet pile installation.
As sheet pile can inhibit the flow of groundwater from the community subsurface aquifers to the river, it can’t be used across the entire flood barrier. Concrete flood walls are being built for areas that require free movement of groundwater beneath, as they will enable this.
The barrier is expected to be completed in Spring 2026.