Award of Excellence: Flood Mitigation, City of Calgary 2013 Flood

The 2013 City of Calgary flood event was unprecedented, impacting much of Southern Alberta, and displacing thousands of people from their homes and businesses. Sadly, four people lost their lives in what was to become the worst flooding in southern Alberta for decades.

Following the event, teams of environmental scientists and structural flood engineers worked tirelessly with the City and Municipalities across the region to understand the cause and affect of the flood, and what could be learned to mitigate flood risk in the future. The City issued a series of RFPs inviting experienced proponents to bring their International and local expertise to solve the long-term (incl. 200-year events) threat from major flood events. 

Some of the Worlds leading flood risk management consultants, contractors and technologists responded. They brought predictive multi-criteria modelling technology to compile, assimilate and interpret all the available data of the event. The hi-tech was used to identify and map the flood zone and flood impact conditions at the confluence of and along the Bow and Elbow Rivers. This multi criteria approach and risk assessment enabled the city to forecast the size and scale of potential future events and plan accordingly, taking into account 1/200 year major events.

One of the consulting firms that played a leading role in the planning and risk management of the project, was multi-award-winning consulting firm, Golder Associates. Golder was highly instrumental in helping the city in its forecasting and planning. The scope of the Golder led project involved conducting detailed surveys of the rivers and tributaries in Calgary to produce hydraulic modelling needed to revise the City’s flood maps. The data from the extensive surveys revealed the flood impact was severe enough to change the contours of the riverbeds and the river geomorphology. Essentially, the power behind the flood had resulted in large amounts riverbed level gravel materials being carried downstream, with woody debris and large rock, boulder size materials scouring of the river embankments and shorelines in the process. In some places, the river alignment had changed dramatically. Other benefits from the work performed by Golder included fish habitat protection and bank stabilization.

Senior members of the BLP team were directly involved in planning and building the appropriate technical resources for the project. The project has contributed to the development of a more sophisticated flood map which help the city to predict which areas will be affected by floodwaters at a given amount of rain and snowmelt. Today, thanks to this project, the City of Calgary can better plan long-term flood mitigation strategies and tactics, and put additional emergency response measures into place.