On June 19 to 21, 2013, an intense rainstorm, combined with snowmelt, resulted in a debris flood that damaged infrastructure and developments located within the Cougar Creek alluvial fan area of the town of Canmore. Homes and lives in the Alberta mountain town were threatened when flood water turned the usually docile Cougar Creek into a raging river. Debris, including felled trees and giant boulders, swept up in the flood that did most of the damage, carving out 130,000 square metres of the creek bed and banks. The damage was estimated at more than $50 million.
As part of a short term mitigation strategy against a similar-magnitude debris flood again potentially impacting the Cougar Creek fan area, the Town of Canmore considered installing a debris net barrier upstream of the fan apex. A RFP (Request For Proposal) was sent out and Geobrugg beat out two other European competitors to provide an engineered geohazard mitigation solution, tailored to the specific site conditions of Cougar Creek. Geobrugg’s extensive experience, full scale testing and unique solutions for this site helped win the contract.
The first line of defence is a ring net 40 metres wide by 6 metres tall. The ring net is made to catch large debris in Cougar Creek in the event of another major flood. Geobrugg Engineer Rico Braendle combined an existing 25 m wide UX barrier with a 15 m wide UX system to cover the 40 m wide section - a clever, practical solution. Other interesting features included a 2 x 3 m animal passage way through the barrier and an earth ramp up and over the barrier for future access. The net will trap debris. The less debris swept down the creek by floodwater, the less damaging the flood.
A year after massive flooding destroyed homes and washed out highways in Canmore, residents are bracing for the spring melt and hoping a $14 million project will protect the community from another disaster.
About the project:: CBC News