Highway 40 South of Kananaskis Lakes - Epicentre of the Storm

The 2013 floods brought enormous changes to the natural and man-made landscapes in many parts of southern Alberta. Associated Engineering was hired by Alberta Transportation to coordinate, prioritize and determine site specific strategies for repairing a 55 km stretch of Highway 40 south of Kananaskis Lakes, southwest of Calgary, Alberta. This section of highway traverses the Highwood Pass, the highest paved road in Canada, and is located adjacent to the headwaters of the Highwood River. This was the epicentre of the June 19 to 22, 2013 rainfall event, where over 325 mm fell, and was the origin for the flood damage and devastation that travelled downstream through numerous communities, including High River.

A total of 117 distinct sites with flood damage were identified, including debris flows across the highway, washouts, culvert blockages, erosional scours, and hydrological changes that carved new channels where they had never existed prior to June 2013. Each site was triaged into one of four categories, which were defined as follows: Stage 1 – required to provide access for construction operations; Stage 2 – required to open the highway to the public; Stage 3 – work off the road surface required to fully restore the highway cross-section; and Stage 4 – major works requiring substantial engineering design effort.

The Stage 1 work was initiated immediately, using Alberta Transportation’s local highway maintenance Contractor. A combined Tender was then issued, with an interim completion date in the fall of 2013 for the Stage 2 work and a final completion date in the summer of 2014 for the Stage 3 work. Some Stage 4 work continues to be worked on as separate Tenders or integrated into the existing contract in 2014.

One of the greatest challenges of the project was the environmental component, as over 50 of the sites required some form of regulatory approval under the Provincial and Federal legislation. Several sites required channel reconstruction, including over 250 metres of a watercourse classified as highly sensitive due to its important bull trout spawning habitat. In order to improve the local stream hydraulics, reestablish connectivity of the channel to maintain fish passage, and protect the highway from future flooding events, the watercourse was re-aligned with its historical channel. Fisheries mitigation measures, engineering plans, as well as hydrotechnical and fluvial geomorphologic assessments were required for these submissions.

This paper will review the effects of the flood, and discuss numerous challenges faced throughout the assessment, design and construction phases of the project.

Author

Kemahan, D.
Rooney, E.

Session title

Emergency Repair and Reconstruction of Transportation Infrastructure

Organizers

Soils and Materials Standing Committee

Year

2014

Format

Paper

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