The District of North Vancouver selected summit Earthworks Inc. to complete a bank Repair and Stabilization project within a confined section of Thames Creek between residential properties 1465 McNair and 4685 Ramsay Rd in 2019.
Due to increasingly frequent high stream flows over the past 5 years, erosion has occurred within this reach of Thames Creek between the McNair culverts and 4685 Ramsay Rd. This project’s intent was to remove a Large Cedar Tree adjacent to 1465 McNair, which was creating a pinch point where flows were concentrated, which caused overbank flooding and a large and deep scour hole that had undermined the existing timber retaining wall. In addition, this pinch point was directing flows towards the left bank resulting in significant downstream erosion.
Summit imported locally sourced rip rap to reconstruct the eroding banks and installed stabilizing weirs within the channel to calm the waters and avoid any further erosion. Temporary access to the channel was achieved via 4685 Ramsay Road by removing the homeowners shed and constructing a temporary access road and ramp so that equipment could traverse the creek bed to the upper reaches. The timber retaining wall was removed, and the jeopardized bank at the McNair property rebuild with a more robust geogrid stabilized rock stack wall using 1200-1500mm wall rock sourced from Squamish, BC. Several bank sections (Approx. 61m in Length) were reconstructed using Class 250kg Rip Rap, and 3″ Minus to achieve a 2:1 slope.
The general scope, outline and project activities include:
- Tree falling, chipping and disposal of 1 old growth Western Red cedar, 1 Alder, 1 Yew and 1 Vine Maple as directed by the District of North Vancouver & Dillion Consulting.
- Removal and retention of homeowners shed, construction of access road & ramp into the creek bed from Ramsey Rd.
- Clearing, Grubbing & Disposal.
- Creek flow isolation & implementation of heavy-duty bypass system during rain events.
Creek Bank & Channel Restoration 2:1 H:V Slope
- 60 Lin.m. of 600-750mm Rip Rap to achieve 2:1 H:V Slope.
- 78 Tons of 3” Minus.
- 20 Lin. m. of 1200-1500 mm Rip Rap at Wall Toe.
- 20 Lin.m. of GEO-Grid Stabilized Rock Stack Wall using 1200-1500mm Rip Rap.
- 50 Lin.m. of 600-750mm Rip Rap to rebuild Creek Slopes.
- 200mm PVC Storm Sewer Extension.
- 100mm PVC Drainage Service Extension.
- Removal of Access Ramp and Reinstatement of bank using 1200mm Rip Rap.
- 55 Yrd3 of Growing Medium.
- Restoration at Ramsay Rd included Sodding, Paving Stones, Planting of two 8cm Caliper Red Japanese Maples, supply and placement of Coco Matting.
- Restoration at McNair Rd included installation of Custom Timber Rail along creek edge, Repairing of concrete pad.
The City of North Vancouver