Nine months after the June 2013 flood The City of Calgary along with the Government of Alberta are continuing work to stabilize and repair riverbank erosion sites.
The City has assessed more than 30 km of damaged riverbank on the Bow River and more than 5 km of damaged riverbank on the Elbow River. Sites were then prioritized based on a triple bottom line policy. This approach considers the economic, social and environmental costs and benefits for each project.
Erosion sites were categorized as critical, high, medium and low priority. Six erosion sites were identified as critical meaning work was required prior to the next high flow event as there was an immediate risk to public safety and critical infrastructure. Riverbank stabilization is complete on critical sites at 8 Avenue at 22 Street SE in Inglewood, Home Road and 52 Street NW and Memorial Drive at 3 Street NW. The City will be returning to these sites to complete final landscaping and plantings which will add to the ability to withstand future high water events Work has begun on critical sites at Memorial Drive at 3 Street NW and will begin at Diamond Cove SE in Douglasdale in the next few weeks. Riverbank stabilization on critical sites will be complete by the end of June 2014.
27 sites were categorized as high priority. These are sites that if not addressed would be at risk for further damage to the bank. In addition the riverbank repair was necessare to facilitate repair to adjacent damaged infrastructure. In April The City will begin work on three sites at Lindsay Park, Langevin Bridge and Sandy Beach. The remaining sites will be completed by the end of June 2014.
“Damage to the riverbanks was extensive,” says Frank Frigo, Senior Planning Engineer with The City. “About 35 km of riverbank have been severely eroded along the Bow and Elbow Rivers. Nearly 100,000 tonnes of rock will be used in riverbank work at the six critical sites.”
Bank restoration design and delivery are very complex and require consideration of a number of elements. In addition there are challenges posed by the location of the work.
“Riverbank work is complex” said Frigo. “We conduct hydraulic modeling to ensure we understand the impacts our project will have on the river and nearby infrastructure, utilities and properties.”
The City is working closely with the provincial and federal governments to ensure river navigation, public lands and environmental regulations are addressed.
For more information on flood recovery projects including riverbank stabilization and erosion sites visit Calgary.ca/floodrecovery.