Phase 1: Spawning Gravel Placement (2025)

 

Phase 1 construction took place between August 18 and September 11, 2025, marking a major implementation milestone for Gold River restoration planning that began in 2021. Far North Contracting Ltd. completed all earthworks, while Ecofish Research Ltd. led construction direction, and environmental monitoring with monitoring support from Mowachaht/Muchalaht First Nation (MMFN). Design and modelling efforts were completed by Ecofish with support from a University of Waterloo Master's student. The spawning gravel size was selected by a team of biologists to provide greatest benefit to Chinook and Sockeye, while a two-dimensional hydrodynamic and sediment-transport model was used to guide gravel placement location.

Outcomes from phase one include the return of adult Chinook, Sockeye, and Coho Salmon to newly enhanced spawning areas, as well as promising observations of Rainbow and Dolly Varden trout and Steelhead. Early indicators suggest conditions will provide increased egg survival rates and improved juvenile fish recruitment, marking a positive start to long-term restoration.

Key project documents informing Phase 1 include the preliminary gravel placement design (before integrating the constriction feature into the design), the University of Waterloo thesis outlining modelling and sediment transport predictions, design drawings, a Construction Environmental Management Plan (CEMP) detailing site isolation methods using a silt curtain to protect water quality, and a construction summary report that includes ortho-imagery and environmental monitoring summary. These documents will help serve as a guide for others planning similar projects.

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Phase 2: Nature-based Infrastructure Constriction Feature (scheduled for 2026)

Phase 2 of the Muchalat Lake Restoration Project will build on the successful Phase 1 gravel placement by installing a nature-based infrastructure rock constriction feature at the lake outlet and placement of additional spawning gravel upstream of the feature. This process-based restoration approach provides a climate change adaptation mechanism by passively slowing the release of water to increase flows during critical low flow periods.

The constriction is designed as several rows of large boulders extending from both banks, approximately 1.5 m high with a 2.0 m wide notch. Hydraulic and sediment transport modeling, flow routing analyses, and shoreline habitat assessments guided the design to maximize ecological benefits while complying with Provincial Dam Safety regulations. By smoothing hydrographs and maintaining higher summer base flows, the feature improves rearing conditions for Steelhead, Rainbow Trout, Cutthroat Trout, and Coho Salmon, and migration conditions for Chinook and Sockeye across 28 km of the Muchalat and Gold River system.

The Project is a novel, low-maintenance restoration approach that does not require mechanical infrastructure or active operation, aligning with Fisheries and Oceans Canada priorities for sustainable habitat restoration. Risk assessments indicate no adverse impacts to shoreline habitat, downstream water users, or human safety. By raising the minimum lake level, the project is also expected to benefit lake recreational users, shoreline vegetation community, and lake margin fish habitat.

Pre-construction planning, permitting, and detailed design were funded by the Pacific Salmon Foundation and Pacific Salmon Commission in 2025. Construction is scheduled to begin August 2026, within the approved fish window, pending final permits. Work is also underway on grant applications to secure funding for the 2026 construction phase. Project documents provided below include design information that can guide the application of this approach to other lakes where downstream fish communities are affected by summer low flows and drought conditions.