This page contains information on the Debris Retention Structure and will be updated on a regular basis during construction - keeping you up to date on impacts in the area.
Online Project Update - June 3, 2021
Please join us on Thursday, June 3 from 2 - 3 p.m. to get an update on the Cougar Creek Debris Retention Structure project and ask any project related questions you have. The event will be hosted on Zoom, please use the following link to access: https://us02web.zoom.us/j/89528214345?pwd=UTVkRS9QWG5UanlvYXJOZDZ0SUs4UT09#success
Construction Impacts - Updated May 13, 2021
- Construction of the Low-Level Outlet and the double emergency bypass pipes is 95% complete and will be operational soon.
- Construction of the embankment foundation is now starting.
- The spillway construction has re-started after a winter shut-down.
- The Lady MacDonald hiking trail will remain closed through to the completion of all blasting activities, expected late summer 2021. The trail closure has been in place to protect workers from rockfall and trail users from blasting hazards. We thank you for your understanding and patience.
- Cougar Creek Canyon remains closed for the duration of construction (tentatively end of 2021).
- The following closures are currently in place:
Long-Term Mitigation: Debris Flood Retention Structure
What will it look like?
- 34m high rock-filled embankment dam (not constructed out of concrete)
- Upstream and downstream faces covered by soil and seeded
- 20m wide rock-cut spillway on the east abutment that includes wildlife egress areas
What will it do?
- Existing channel and downstream culverts can accommodate 50-60 m3/s, but a natural event on the creek could easily reach 80 m3/s peak flow with 20% debris (fine sediment to large boulders, including gravel and woody debris)
- The Structure reduces peak flow to 45 m3/s. It further reduces the quantity of debris and removes the larger debris
- The risk to downstream private and commercial properties, as well as infrastructure, is therefore reduced to an acceptable level
- There is no water retention during regular operation (dry dam) – water flows freely through a low-level outlet
- A high capacity spillway is required to ensure flows can bypass the structure during an extreme flood event
Frequently Asked Questions
Alberta Parks and the Town of Canmore considered constructing an alternative route around the closure to access Cougar Creek Canyon. Due to the challenging steep terrain on Lady MacDonald and Grotto Mountain, Alberta Parks determined that closing access is the best alternative for ensuring public safety.
RIDGE Environmental Planning will serve as a third-party Environmental Monitor during the construction of the Cougar Creek Structure. The contract was awarded at a value of $159,000.
Water Act Approval
Alberta Parks Disposition (land within the Bow Valley Wildland Provincial Park that is being leased to the Town of Canmore for the construction, operation, and maintenance of the Debris Flood Retention Structure).
1. The Construction Environmental Management Plan, that describes principles, best practices and specific requirements during the construction of the project; and
2. The Water Quality Management and Monitoring Environmental Protection Plan, that describes the water monitoring requirements during construction of the project.
Moreover, the contractor is required to submit to the Town and its consultants several work plans and environmental protection plans (EPPs) that need to follow the requirements of the guiding documents described above. Examples of plans required for the project: Care of Water work plan, Erosion and Sediment Control EPP, Wildlife and Human Conflict EPP, Invasive Species Control EPP, etc.