Our Current Proposed Route
To reach Lelu Island off the coast of Port Edward, Prince Rupert Gas Transmission (PRGT) plans to construct approximately 120 kilometres of pipeline in the ocean. The pipeline would enter the water at Nass Bay, travel through Iceberg Bay and Nasoga Gulf, and continue southwest along the Portland Inlet.
PRGT has been working closely with Aboriginal groups and stakeholders and has used their feedback along with environmental and engineering studies to determine the proposed route that we have today (see purple line on the map).
On land and is Nass and Iceberg bays, we would construct a single 48-inch diameter pipeline. As it then enters the ocean again at Nasoga Gulf, there would be two 36-inch pipes, which would be positioned along the ocean floor. While laying pipe in a marine environment is relatively new in Canada, it is a widely used practice done safely around the world. We would use practiced and effective marine pipeline construction techniques that minimize potential environmental effects and comply with all federal and provincial permitting regulations. We are working with Canadian and international marine design firms to determine the best construction methodology for the pipeline and the best route for the pipeline to follow.
How a Pipeline is Placed on the Ocean Floor
A specially designed vessel outfitted for the installation of marine pipelines would be used to lay the pipeline on the ocean floor. After the pipe segments are welded, they would be slowly fed into the water at an angle that avoids straining the pipe. The completed pipeline would typically rest on the seabed, but some sections may be buried in a trench to avoid obstruction and to protect that section. The pipe can be coated in concrete or covered for further protection.
Protecting the Sensitive Ecosystem
Minimizing effects on the marine environment has been a key consideration in the identification of the proposed route. Undersea construction methods will also be optimized to minimize effects to sensitive areas for fish and other marine life wherever possible. Habitat surveys and mapping are being used to support this process.
Due to its weight, the pipe would naturally partially bury itself in softer sediments on the seabed so that only a portion of the pipe may remain above the level of the sea bed. In areas with harder sediments, a trench could be dug to bury the pipeline, or the pipe could simply rest on the seabed. The pipeline itself, and any rock used to protect or support the pipeline, may provide additional fish habitat.
Valuable fish habitat typically exists in shallow waters close to shore, however most of our marine pipeline route is in water as deep as 600 metres. Where the pipeline is in shallow water, we want to ensure that the environment would not be adversely affected. We are planning the route to avoid sensitive habitats where possible, or minimize potential effects on fish and other aquatic life.
Keeping Safety Top of Mind
Natural gas – the same natural gas used in homes around British Columbia – poses few environmental risks to ocean habitat in the unlikely event of a leak from a pipeline on the seabed. The natural gas would form bubbles and quickly rise to the surface with no direct effect on water quality. Natural gas is lighter than air and will quickly disperse upon reaching the surface.
PRGT’s pipeline control system monitors all pipelines 24 hours a day and would immediately warn of a leak in any section of the pipeline and determine where the leak has occurred. Valves located on land at each end of the offshore pipeline would allow the release to be isolated. Crews would be dispatched to assist with the isolation and to establish an Incident Command Post. Detailed Emergency Response Plans are being developed to deal with any such incidents. These plans include cooperation with local emergency service groups, regulatory agencies, landowners, community officials and the media throughout any incident.
A Question of Timing
Once regulatory approval and a final investment decision is received, construction work on the pipeline route will begin. Placing the marine portion of the pipeline is tentatively scheduled to begin in 2018 and continue into 2019. Throughout the construction schedule, we will keep Aboriginal groups and stakeholders informed of our progress, and ensure that questions and concerns are promptly addressed.