Calgary Downtown Flood Barrier and Public Realm Improvements

In 2013, Calgary faced a significant natural disaster with downtown and nearby areas affected by extensive flooding, marking the largest such incident in Canadian history at the time. Over a two-year period, Graham successfully executed the Flood Barrier project, a continuous 1.39 km long structure comprising steel sheet piles, earthen berms, concrete walls, and demountable stop log openings designed to withstand a 1:200-year flood event. Simultaneously, the Eau Claire Promenade underwent rebuilding and revitalization, a crucial component of Calgary’s extensive riverside pathway system.

Scope of Work

Stretching from the new Jaipur Bridge to the 4th Avenue flyover, the Downtown Flood Barrier Project includes a sheet pile flood wall with demountable flood barriers, upgrades to the Centre Street Bridge ramps, a new lagoon dock, utility installations, hardscaping, and landscaping. The Centre Street precast wall included the installation of a cofferdam, along with in-water piling and earthworks. This project involved numerous stakeholders and unique architectural elements, including a feature dock, signage, and benches. Working in the downtown core required extensive pathway and road detours, as well as interfacing with the public.

Environmental Management

Environmental management was crucial on this project, which included in-stream works in the Bow River and management of existing contaminated materials. Construction of the MSE wall for Centre Street required the installation of a turbidity curtain, construction of a berm and working platform within the river, drilled piles in the wet, and re-establishment of the armored bank. A water treatment system was implemented to ensure that all water discharged from the isolation complied with the Water Act Approval.

Most areas of the project were considered contaminated, and Graham worked with the City of Calgary and the environmental consultant to carry out a detailed testing program to characterize the soil across 1.3 km of riverfront. Materials were segregated, and over 10,000m³ of soil was exported and replaced as contaminated waste. Graham was also responsible for the development, implementation, and maintenance of Erosion and Sediment Control and Tree Protection plans across many different work fronts over three years.

Project Completion

The project opened six months ahead of schedule.