A few weeks ago, we told you about a trenchless construction method called horizontal directional drilling that can be used to minimize the environmental impact of installing pipelines across rivers. In this post, we want to take a broader look at the environmental considerations and best practices for watercourse crossings (PDF).
Greg Bryant is a senior environmental planner at TERA Environmental Consultants, a firm that works with pipeline companies to reduce the environmental impact of their projects. He provided us with a list of environmental concerns that need to be taken into account when a pipeline crosses water. Here are some of those considerations:
These are just a few of the factors companies need to think about when building watercourse crossings. Other considerations may include traditional land use by Aboriginal communities. For a comprehensive list of environmental considerations, check out page 71 of this publication: Pipelines Associated Watercourse Crossings, Third Edition (PDF).
Bryant explained that choosing a location best suited to maintaining the stability and the integrity of the pipeline is the “first and foremost consideration” when planning where a pipeline will cross water.
“The crossing needs to be geotechnically sound (i.e. stable slopes and banks),” said Bryant. “The preference is to cross at a straight stretch of the river as opposed to locating the crossing on a meander bend.”
There are many other factors that need to be considered as well, including the presence of fish habitat.
Generally, a crew who specializes in watercourse crossings is used during installation, Bryant explained. Here are some other construction-related best practices Bryant provided:
Crossings and approach slopes are monitored to make sure banks and slopes remain stable, said Bryant, especially after “high streamflow events” such as floods.
There are other special steps used to keep the pipeline operating safely (in addition to regular integrity monitoring). For example, thicker pipes, special coatings and block valves can all be used. Keep checking our blog, we’ll tell you about some of those measures in a couple of weeks.
Want more info? Check out these publications:
The Canadian Energy Pipeline Association represents Canada’s transmission pipeline companies who operate approximately 115,000 kilometres of pipelines in Canada. In 2012, these energy highways moved approximately 1.2 billion barrels of liquid petroleum products and 5.1 trillion cubic feet of natural gas. Our members transport 97 per cent of Canada’s daily natural gas and onshore crude oil from producing regions to markets throughout North America.