A Collaborative and Innovative Approach
During the Alberta floods of 2013, erosion of the river banks encroached near private property and caused sections of the park trail to be washed away putting properties in Grayling Terrace adjacent to the Hangingstone River at risk. To address this challenge, WSP was retained by the Regional Municipality of Wood Buffalo (RMWB) as the prime consultant for the Erosion Control Works in the Hangingstone River adjacent to Grayling Terrace. The scope of this project was to complete detailed design, prepare tender documents, provide construction inspection and administer the contract. The work included rock protection of the outer banks, floodplain grading of the interior banks and offloading the steep slope of Beacon Hill. To stabilize Beaconhill slope and reduce risk of further river damage, over 50,000 cubic meters of material from the upper crest was off-loaded using four excavators in series to account for the steep slope.
Work was conducted during the winter months to ensure a rapid repair and reduce further erosion to the project area. This required careful planning for conduct construction activities on the ice surface, including the development of ice bridges. Winter construction has its challenges; especially with work within a water body. Techniques such as ice bridges, cofferdams, and fish salvages were used to perform the work. In a shared effort between the consultant, contractor and owner, construction was able to proceed in the environmentally sensitive area. Driven by environmental deadlines, the work within the river channel was successfully completed prior to ice breakup and spring runoff. The remainder of the remediation and landscaping work was completed in October, 2015.
The scope of work included:
- Topographic and river surveys
- Completion of required environmental and geotechnical assessments
- Detailed design of bank protection, floodplain relief zones, and slope stability
- Landscaping rehabilitation
- Constructability review
- Evaluating construction risk
- Coordination of sub-consultants
- Public relations
- Construction inspection and contract administration
The project was funded in part through a grant under the 2013 Flood Recovery and Erosion Control Program (FRECP) administered by Alberta Environment and Sustainable Resource Development (AESRD) and the 2013 Disaster Recovery Program (DRP).
