Stories from our 2015 Enbridge Safety Report to the Community (Part 1)
Mike Hill and his team submerged themselves in a challenge—and came up with a state-of-the-art solution.
We build our pipelines at Enbridge to keep watercourse crossings to a minimum, but safely crossing rivers, streams and other bodies of water, from the smallest creek to the largest river in North America, is a fact of life in the pipeline business. It’s the same with building highways and railroads. You can’t travel a significant distance in any given direction without encountering a watercourse that will need to be crossed, one way or another.
Of course, rivers and streams can flood, and when they do the rushing water can expose or undermine our pipelines. When there’s a risk of that happening, we want to take steps beforehand to shut down and isolate the affected line.
That’s the challenge Hill and his team addressed in early 2015 when they developed a new flood monitoring system to add another layer of protection where Enbridge pipelines cross waterways.
Working alongside an engineering firm, they tapped into the flood forecast and streamflow data collected by the United States Geological Survey (USGS) and Environment Canada, and modeled the impact of flooding on riverbeds at thousands of watercourse crossings. Then, they established monitoring for times when flooding was likely—and procedures to shut down and isolate affected pipelines when high streamflow exceeded a pre-set level.
“We’ve always treated watercourse crossings with care—from thicker pipeline steel to strategically placed isolation valves,” says Hill, a manager of integrity planning with Enbridge. “In recent decades, we’ve used horizontal directional drilling to tunnel the pipeline well below the riverbed so that it is not affected by streamflow.”
“One of the crossings that we were looking at was where our Ozark Pipeline crosses the Mississippi River,” says Hill. “It’s a crossing where we see flooding pretty regularly, and where the riverbed can change quite a bit when the Mississippi is running high.”
The team launched the new flood monitoring system in April—and, just two months later, got a chance to put it to the test when the Mississippi began to flood.
“On June 28, the flood waters rose,” says Hill, “and (Enbridge’s operations control center in Edmonton) and our operations folks in the region took quick action to shut down the line and close the isolation valves.”
Five days later, after flood waters receded, an on-site survey showed the pipeline was safe to restart. However, Enbridge’s operations and engineering staff took a conservative approach—completing a second survey, reviewing other potential threats to the health of the line, and undertaking an engineering assessment before giving the go-ahead to begin safely moving crude oil through the line again.
“Creating the flood monitoring system gave us another tool to keep an eye on our pipelines so that we can be even more proactive in controlling hazards that could contribute to an incident,” says Hill. “We’re always trying to improve all of our monitoring programs and systems to be ready for whatever comes our way.”
(TOP PHOTO: Enbridge's flood monitoring system is based on warning and high streamflow thresholds, with procedures to shut down and isolate affected pipelines during flood conditions.)
