Publication: International Journal on Hydropower & Dams
Issue: Issue Four, August 2017

The 16 MW Box Canyon hydroelectric project ranks among the most hydraulically complex of any run-of-river hydro project in North America, if not the world. The project, which is located in the McNab Creek watershed, 40 km northwest of Vancouver, British Columbia, has nine intake structures on different creeks and tributaries. All nine feed into a single, high-pressure penstock that directs water to the powerhouse containing a single six-jet vertical axis Pelton generating unit.

The owner, Box Canyon Hydro Corp (a subsidiary of Elemental Energy Inc.) retained Knight Piésold Ltd to assist with:

• concept development, optimization, environmental assessment, and permitting;
• detailed design; and,
• operational monitoring of the facility.

Initial investigations began in 2004, at which time the project concept was a 7 MW facility with a single intake on Box Canyon creek. Through optimization studies, which included site investigations and detailed hydrological studies, Knight Piésold revised the design to the current 16 MW arrangement. The design required addressing hydraulic, waterhammer and environmental flow release complexities, which are not typical for a single intake, run-of-river hydro project.

The project is within the traditional territory of the Squamish Nation, a valued partner on the project, and includes intake structures on three main tributaries to McNab Creek (Box Canyon, Marty, and Cascara Creeks) as well as six minor tributary diversions. Each intake is designed to meet unique water licence conditions that are intended to address the various hydrology, river morphology, and fish species distributions along the creeks and tributaries. The general arrangement and a schematic of the project are shown in Figs. 1 and 2. Key components of the project are highlighted in the photographs, and details for the major components of the project are summarized in the Table.

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