Prince Rupert Gas Transmission Pipeline Project Hydrotechnical Water Crossing Designs

CLIENT: Prince Rupert Gas Transmission Ltd. (Joint Venture led by TransCanada Corp.)

Prince Rupert Gas Transmission Ltd. is developing the Prince Rupert Gas Transmission Project, which proposes the construction of an approximately 800 km long natural gas pipeline across northern British Columbia. The 1220 mm pipeline will cross numerous watercourses, including 73 significant water crossings.  

NHC was retained to categorize water crossings and perform a hydrotechnical risk assessment and scour analysis at 45 crossings. Additionally, NHC provided minimum depth of cover and setback design recommendations for the pipeline water crossings.

Proposed pipeline water crossings identified by the prime consultant, BGC Engineering, were categorized into typical or non-typical. Typical crossings had no significant hydrotechnical hazards and a standard depth of cover was applied. Non-typical crossings had hydrotechnical hazards identified that could potentially create a risk of exposure in the stream and required design recommendations. A 200-year scour potential analysis was performed for all non-typical crossings to help recommend an appropriate depth of cover. Pipeline setbacks were also recommended, based on surveyed cross sections of the proposed crossings, data collected during NHC field visits, and hydrotechnical hazards at the crossing.