In November 2021, record rainfall occurred in southwest BC, resulting in historic flooding on the Nicola River. The impacts to infrastructure and in-stream habitat were immense. At the Shackan 11 reserve, approximately 40 km northwest of Merritt, BC, high flows resulted in extensive erosion and loss of reserve land, impacts to cultural sites, and loss of fish passage along Skuhun Creek, a tributary of the Nicola River that provides critical habitat for salmonids, especially threatened Thompson River Steelhead.

Led by Scw’exmx Tribal Council (STC) and Shackan Indian Band (Shackan), and facilitated by the Department of Fisheries and Oceans Canada (DFO), a project team of engineers, geoscientists, and fisheries habitat specialists from BGC Engineering Inc. (BGC) and Kerr Wood Leidal Associates (KWL) collaborated to design and implement long-term restoration efforts. Starting from conceptual stages, design of the project was undertaken as a complete multi-disciplinary collaboration and included significant input from Rock Solid Industries Inc. (RSI), the project construction contractor, on aspects relating to overall constructability and construction staging. The result was a restoration effort that blended hard armouring approaches and aspects of nature-based design to a degree that is presently uncommon for such projects.

Key environmental aspects of the project design included the re-establishment of fish passage along Skuhun Creek, the creation of a riprap groyne and large wood reef at the mouth of Skuhun Creek to provide a thermal refuge for fish, and an elevated floodplain area to increase riparian habitat within the project area. The entire project area was revegetated with native plant species including willows, cottonwoods, lodgepole pine, saskatoon berries, and a mix of other shrubs. The project team developed and implemented a novel approach to improve the water retention capacity of the riprap armouring to support the planting of live stakes.

Collaboration was integral to project success from the beginning. Early meetings brought together voices from the project team, DFO and Shackan, integrating engineering design concepts with indigenous traditional knowledge to develop a design to restore fish passage in Skuhun Creek and stabilize the eroding high bank on the Nicola River. All parties agreed that the mitigation works should not only satisfy hydraulic stability criteria but also improve the quality of aquatic and terrestrial habitat throughout the project area.

Constrained by tight timelines, it was imperative that the in-stream work be completed prior to mid-April 2024 to prevent further erosion and to avoid construction interfering with the Steelhead migration period. BGC completed a hydrotechnical assessment including a flood frequency analysis and hydrodynamic modelling to iteratively assess design configurations with all parties involved. The project rapidly advanced from a preliminary design in November 2023 to construction in February 2024. Due to the urgent nature of the project, field-fitting during construction was essential. BGC and RSI worked closely during construction, making design modifications on a near daily basis, with RSI efficiently capturing design changes by dynamically updating 3D design surfaces for their GPS machine-controlled excavators. The project reached completion on time with project costs on budget, totaling approximately $7M.

The project is expected to have lasting environmental benefits. Stabilization of the high bank eliminates a large source of fine sediments, improving downstream salmonid habitat quality. The restoration of Skuhun Creek reconnects access to several kilometres of high-quality mountain stream fish habitat, while construction of a groyne and reef at the mouth of Skuhun Creek creates a vital and durable thermal refuge; habitat that is critical for survival of salmonids in a changing climate.