Blog: Morice River crossing to be finished — safely

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Coastal GasLink continues to safely advance the tunnel below the Morice River, through which CGL’s natural-gas pipeline will run.

CGL reports that the tunneling process is anticipated to be completed this winter, which will mark the completion of all 10 major watercourse crossings on the pipeline route.

And the project is showing up the fear-mongering nonsense being spouted by protester and media-star Molly Wickham.

She has declared: “The disturbance and the sediment alone from drilling underneath the river will destroy our ability to drink that water forever. The sediment alone could destroy the salmon spawning eggs. It could destroy the airflow underwater or underground water flow and oxygen that gets into the spawning grounds.”.

She offers no evidence as to why a tunnel 11 metres below the riverbed would do any of these things, nothing from a fisheries scientist, an engineer, a geologist, a hydrologist, or a soil scientist or any other expert; just her own activist assumptions.

She offers no recognition that the Morice River crossing is only one of many successful “trenchless crossings” of water on the Coastal GasLink route. They include the use of Direct Pipe Installation® under the Kitimat River (with a 270-metre tunnel) and horizontal directional drilling (HDD) under the Murray River in northeast BC in 2021 (with a drilled pipe-tunnel 1.3km long.)

And they were done with no environmental destruction — and no blockades or vicious axe-attacks on crews and equipment as has happened to Coastal GasLink in Morice River territory.

(The Independent Contractors and Businesses Association of BC has offered a reward of up to $100,000 for info leading to any arrest and charge in the Feb. 17 attack on Coastal GasLink workers and equipment.)

To date, nine of 10 major CGL watercourse crossings have been safely completed. Now comes the Morice River.

It is indeed a salmon river. It supports chinook, pink, coho and sockeye salmon, and steelhead and trout.

“There are fish of one species or another that are in that waterway at all times of the year,” says Michael Price, a fisheries biologist and researcher with Simon Fraser University.

But the advanced “micro-tunneling” technique used by Coastal GasLink is a proven method of using a remote-controlled tunnel-boring machine, and then hydraulic jacks to push concrete casing segments through the tunnel deep under water bodies. The pipeline is then safely pulled through the tunnel created by the concrete casing.

And in this case, the pipeline will be a full 11 metres beneath the riverbed.

As Coastal GasLink notes: “After completing environmental and technical assessments such as water flow, bank stability, wildlife, vegetation and the quantity and quality of fish habitats, it was determined that a trenchless micro-tunneling crossing would be the safest method for construction to cross the Morice River.

“Trenchless crossings are proven to allow pipe to be installed under the water body without ever affecting the flow of the river or stream. Currently there are thousands of trenchless crossings throughout BC, operating safely under rivers and streams of all sizes.

“This won’t be the first time that micro-tunneling is used. In fact, it’s regularly used in our communities for public works and infrastructure projects, such as hydro lines, sewer systems and other utilities in BC, and we have support from local and Indigenous communities to use this method at the Morice.”

The HDD technique has been safely used for more than 30 years to place pipelines under highways, railroads, rivers and streams, populated urban areas, and environmentally sensitive areas. Like micro-tunneling, it has also been used to install power cables, water lines, sewer lines, and fibre-optic telecom cables.

Following geotechnical and geophysical studies, feasibility studies, and engineering design, the drilling for a trenchless project starts at a staging site on one side of the river.

A small drilled tunnel is angled and directed to run well under the river bed (11 full metres in the case of the Morice), then angles upward to a staging site on the other side of the river. At no point does the tunnel impact the riverbed or the water.

This first tunnel is a small “pilot” tunnel, which is electronically checked to ensure it’s in the right place and is not in any way going to impact the river. The tunnel is then enlarged by “reaming”, in repeated passes, to the diameter needed for the pipeline itself to go through.

Or, in micro-tunneling, it is reamed until it is the right size for the segments of concrete pipe to be  pushed through by jacks to form a strong tunnel through which the pipeline will run.

For Coastal GasLink, the pipe will be 48 inches (just under 122 cm) in diameter, the same size as has been used in many trenchless crossings for major pipelines.

When the final tunnel is tested and checked and ready, a section of the main pipe is literally pulled through the tunnel from the starting point to the finishing point. The process is monitored throughout.

The pipe then is tested, and then can be connected to the main pipeline. The flow of natural gas through it can begin.

After the pipe is pulled through the its tunnel, the staging sites on both sides of the river are restored.

And, throughout, the process for Coastal GasLink is being monitored by First Nations people.

Here are two videos that show how the tunneling techniques work:

  • From Coastal GasLink, Water crossings – What is microtunneling?
  • From Trans Mountain, this video shows the technique and technology used to direct its TMX expansion oil pipeline under the Fraser River in Coquitlam: https://youtu.be/ArbzW29Qqmo

(The TMX project from Alberta to tidewater at Burnaby includes some 40 trenchless crossings, of up to 1,600 metres in length.)

(Posted here 14 December 2022)

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