How are pipelines installed across rivers?

In order for pipelines to transport the energy we need across the country, pipelines must sometimes cross rivers.

The environmental protection of these rivers is definitely on the minds of Canadians, and it’s on the minds of pipeline companies as well. That’s why the industry has started using technically advanced construction methods such ashorizontal directional drilling to build pipelines that cross sensitive areas.

What is horizontal directional drilling (HDD)?

HDD construction in action (photo courtesy of CCI)

HDD is a trenchless construction method that, in the simplest terms, involves drilling a path underneath a river or other obstacle (like a road) and basically threading the pipeline underneath.

CCI is a Canadian company that specializes in using HDD to construct pipelines that cross bodies of water. Dave Dupuis, the company’s chief operating officer, explained that HDD eliminates the need for equipment to enter the water, like in the open-cut method of installation.

“There is absolutely zero impact in regards to the environment because we are going underneath (the water), so there is no surface disturbance whatsoever for the construction and installation,” said Dupuis, who added that disturbances only occur where the machinery is located and at the exit point where the pipe is joined.

If you want more info on how HDD works, CCI was featured on the TV series “Frontiers of Construction,” and you can download the video on CCI’s site (just scroll to the bottom of the page for the link).

How does HDD protect the environment?

“It’s really the most environmentally friendly method of installation across a water body,” Dupuis explained.

He pointed out that because there is no physical activity inside the water, “fish habitats are not disturbed.”

Riverbank stability is another benefit associated with the HDD construction method.

“There is no disturbance, so there’s no possibility of (the bank) sloping in or eroding into the water body,” Dupuis pointed out.

Construction techniques are continuously improving with technology

Because the pipeline industry wants to continually improve its performance, it is constantly exploring new technologies and advancements to existing technologies.

“Not wanting to effect the environment and having a good social license has really been a key component for pushing this technology forward over the last 15 to 20 years,” explained Dupuis about the use of HDD in river-crossing construction (PDF), but he also added that HDD is not the only trenchless construction method.

Dupuis explained that his company, a member of the new CEPA Foundation, chooses the best technique based on the river’s local geology. And those techniques are always improving. For example, last August, CCI completed the very first mircotunnel installation for a pipeline in Canada.

source : http://www.cepa.com/how-are-pipelines-installed-across-rivers