The Calgary Zoo was severely impacted by the historical June 2013 floods in southern Alberta. Located primarily on St. George’s Island, a 32 acre body of land in the middle of the Bow River, the Zoo was inundated with 1 to 2 m of water. Total damages approximated $50 million. The flood mitigation consists of bank armouring, earth berms, a sheet pile installed below and above ground around St. George’s Island, and a dewatering system to manage stormwater and groundwater. These measures will protect the zoo against water levels up to 1 m above the 2013 flood, and 0.5 m above the 1:100-year flood elevation.
Matrix acted as the prime consultant immediately after the flood – we were responsible for design, regulatory approvals, construction specifications, contractor selection, and directing construction of the bank repairs. For the conceptual flood mitigation options we brought additional engineering consultants onto the design team, and for the detailed flood mitigation component, we were responsible for river engineering design of the sheet pile wall and berms, regulatory approvals, environmental assessments, and directing instream construction.
Bank repairs were designed, permitted, and constructed within 3 months. In several locations, due to space constraints, it was necessary to construct the flood protection wall within the floodway. We assessed river hydraulics and demonstrated that these encroachments had no negative impact on flood levels.
The zoo was able to partially reopen within 3 months. Bank repairs and flood protection designs integrated fish habitat features, allowing for timely regulatory approval of instream works without the need for a separate and costly project.