Located in the North Coast region of British Columbia in Kitimat, Sumgas Creek was modified in the 1950s. Eight large weirs and two culverted road crossings were constructed as part of the stormwater drainage system for the District of Kitimat. Unfortunately, they blocked upstream salmon migration and isolated a population of cutthroat trout in the creek headwaters. When LNG Canada (LNGC) was looking for a fish habitat restoration opportunity near their LNG Export Facility, Sumgas Creek was an obvious choice that met stewardship objectives as well as regulatory needs.

Stantec’s collaborative, multidisciplinary team was engaged by LNGC to help remove the barriers and re-naturalize the creek. Our engineers, geomorphologists, and biologists worked together throughout design and construction to make this project a success. Starting with a feasibility assessment in 2019, our team drove engineering, environmental, and regulatory aspects of the project simultaneously at each phase of design advancement. We collaborated closely with LNGC throughout the process, tailoring our studies and design criteria based on requests and requirements from the District of Kitimat, regulators, and the public.
The team continued our collaborative work all through construction. Through LNGC’s proactive engagement of the construction contractor, Bird, Stantec was able to develop the issued for construction design and the final detailed permit applications with great certainty. Our on-site engineers and qualified environmental professionals supported Bird with last-minute challenges, working together on design adjustments to meet fish and hydraulic needs and developing innovative solutions, including a first-of-its-kind cutthroat trout egg salvage. Water was re-introduced into the newly constructed creek on September 25, 2023, and we observed coho salmon spawning upstream in October!

Our design approach was rooted in two key goals: (1) make all slopes and jumps passable for adult and juvenile trout and salmon, and (2) improve public safety.

As the culverts had become perched over time and the weirs created artificial drops and low-gradient channel segments, fish passage upstream and sediment transport downstream were both disrupted. We used natural channel design principles to develop a stable, natural space that meets the needs of fish, wildlife, neighbours, and the District of Kitimat. The new channel’s gradient follows a river continuum concept curve to enable fish passage and sediment conveyance between the headwaters and the floodplain. We knew that the drop height would have to be limited to 15 cm for passage of juveniles fish. Abundant cover, deep pools, and native riparian vegetation rounded out the fish habitat portions of the design.

Originally, the weirs were topped with fencing to protect the community from accidental falls into shallow water. While fencing is a mitigation measure, Stantec wanted to remove the fall hazard completely. We achieved this by re-grading the banks and creating a floodplain and benched riparian slopes. LNGC planted native vegetation along the creek and rebuilt the walking path, benches, and lighting for the neighbours’ enjoyment of the new park space. The District of Kitimat is responsible for water management, so we incorporated a dredge pocket into the design to meet their needs as well.

Gaining 15 m of elevation in steps of 15 cm or less is no easy feat! We did it—by removing long-standing barriers and re-naturalizing the creek. 15,800 m2 of habitat is again accessible to salmon, who found the new habitat in less than a month. The re-graded riparian slopes are safer, and the District of Kitimat can complete maintenance at the custom-designed dredge pocket access point. Best of all: children at Kildala Elementary students will be able to see migrating salmon from their school.