16 MW Box Canyon Hydroelectric Project

Client

Box Canyon Hydro Corp. (a subsidiary of Elemental Energy Inc.)

Location

British Columbia, Canada

Highlights

Three main intakes and six tributary intakes are connected to a single, high-pressure penstock
Over 8 km of interconnected low- and high-pressure penstock was constructed in steep and remote terrain
The facility operates while maintaining unique minimum instream flow, maximum diversion rate, and ramping criteria at each of the three main intakes
A backflow valve prevents flow from Marty Creek to Box Canyon Creek
An alliance contracting model was adopted where owner, contractor, project manager, and engineer all worked together to achieve on time and on budget construction delivery

Project Overview

The 16 MW Box Canyon Hydroelectric Project, which is located in the McNab Creek watershed on the north side of Howe Sound, BC, may have the most hydraulically complex design of any run-of-river hydroelectric project in North America, if not the world. There are multiple intake structures on different creeks and tributaries, all feeding into a single, high-pressure penstock that directs water to the powerhouse containing a 6-jet vertical axis Pelton turbine generating unit.

The project has three main intakes and six tributary intakes that address the unique hydrology, river morphology, and fish species distribution along McNab Creek and its tributaries. It has an 8.6-km-long water conveyance system of interconnecting pipelines and high-pressure penstocks that handles varying intake elevations and flow contributions, requiring the addition and design of surge facilities and check valves. The project design also took into account the complex hydraulic transient pressures (water hammer) and provided unique environmental flow releases at each of the diversion weirs.

Project Role

Knight Piésold assisted the owner, Box Canyon Hydro Corp. (a subsidiary of Elemental Energy Inc.), with concept development, optimization studies, environmental assessment, and permitting, that continued through to detailed design and operational monitoring.

The original project concept was a 7 MW facility with a single intake on Box Canyon Creek. Knight Piésold optimized the design to the current 16 MW facility with multiple intakes, addressing complexities not typical in a single intake, run-of- river hydroelectric project.

Services provided include:

Intake hydraulics, structural, and civil design
Powerhouse structural and civil design
Penstock transient analysis
Geotechnical and site investigations
Bridge, foundation, and riprap design
Electrical and mechanical analysis
Terrain hazard assessments
Project management

Knight Piésold has been involved with the project since initial investigations began in 2004 until its commissioning in early 2016. The project generates approximately 46 GWh/year of renewable energy, enough to power approximately 4,500 homes.

Awards

Tree for Life Award, 2017 Canadian Consulting Engineering Awards
Award of Excellence, Natural Resources, Mining, Industry & Energy Category, 2017 Canadian Consulting Engineering Awards
Award of Merit, Energy & Industry Category, 2017 ACEC-BC Awards for Engineering Excellence