Bearskin Lake - Flood Emergency, Road Assessment and Design - Mahan Bridge

In November 2019, Bearskin Lake First Nation (BLFN) experienced a rare flood emergency in the community.  Ice jamming at White Sands Rapids to the east of the community caused Michikan Lake levels to rise significantly resulting in damage to roads within the community. The damage restricted movements within the community and resulted in a state of emergency requiring evacuations that lasted approximately three weeks. The structural integrity of the roads and crossings were significantly impacted at several locations within the community.

The subject of this Project is the Mahan Bridge and causeway, which was damaged during the flood event. This crossing is the winter road connection to the community and provides access to the majority of its aggregate sources. The flood event stripped and undermined the bridge abutments and eroded the approaches to the bridge. As an emergency measure following the flood event the approach roads were temporarily built-up with poorly-graded, uncompacted aggregate. The total affected area is approximately 650 m long. Repairs will include the addition of rip rap along the causeway, installation of one new culvert, and raising the road surface elevation.

Approximately 0.6 m thickness of granite rip rap will be added on both sides of the full causeway length (approximately length of 130 m), including around the inlets and outlets of the two existing culverts and the new culvert to protect against erosion. A geotextile liner will be installed beneath the new rip rap.

The lake bed will be subcut at the culvert inlets and outlets locations with new rip rap to be placed within 3 m of the culverts. Rip rap will also be added around the bridge abutments and cribbing where previous material has eroded. To increase flow capacity, one new 2,000 mm diameter CSP culvert will be added adjacent to the existing culverts, with the exact location to be determined on site where advantageous for existing drainage. The road surface elevation will be raised to 226.5 m by placement of local gravel fill followed by appropriate granular material (granular A, granular M) for road topping.

Additional approvals are anticipated to be required from DFO and Transport Canada. Given that the project is likely to result in destruction (infilling) and alteration of fish habitat it is expected that Authorization will be required in accordance with the Fisheries Act. The project is also expected to require approval from Transport Canada as work on bridges and causeways is considered a "major works" under the Canadian Navigable Waters Act.  An Application for Approval will be submitted.

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Disclaimer

This map is for illustrative purposes. The markers represent the approximate locations based on available data. More than one marker may be identified for a given assessment.

 

Latest update

June 14, 2021 – Indigenous Services Canada issued its Notice of Determination for the Bearskin Lake - Flood Emergency, Road Assessment and Design - Mahan Bridge - Canada.ca (ceaa-acee.gc.ca) and determined that the project is not likely to cause significant adverse environmental effects.

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Key documents

Contacts

Indigenous Services Canada - Ontario
Julieta Werner, Sr. Environment Officer
100 Anemki Place, Suite 101
Fort William First Nation, Ontario P7J 1A5
Telephone: 807-355-1196
Email: julieta.werner@canada.ca


  • Location

    • Bearskin Lake First Nation (Ontario)

  • Nature of Activity

    • Bridges

  • Assessment Status

    Completed

  • Start Date

    2021-01-07

  • Proponent

    Bearskin Lake First Nation

  • Authorities

    • Indigenous Services Canada

  • Assessment Type

    Project on federal lands

  • Reference Number

    81270

Nearby assessments

...within 200 kilometres
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