Ongoing pipeline rehabilitation and maintenance is essential to protecting oil and gas assets, and the environment surrounding this vital energy infrastructure. To mitigate pipeline exposures, McClure Engineering Company (MEC) has partnered with Blackstone Environmental to provide environmentally focused solutions built on a strong topographic survey foundation.
Pipeline exposure before (above) and after (below). MEC and Blackstone Environmental collaborated on a exposure mitigation project along a tributary to the Big Sioux River in Iowa.
MEC is experienced with all phases of pipeline survey as well as topographic survey, close interval survey and terrestrial LiDAR. Blackstone Environmental specializes in stream bank stabilization and erosion control engineering to address exposed pipeline or at-risk foundations for cable-suspended pipelines.
“Usually the areas we work on are stream crossings or flood plain areas that have been impacted by erosion from high precipitation and flow,” said Rowley Tedlock, senior project manager with Blackstone Environmental. “After the pipeline company identifies the exposure, we assess the risk level, stream hydraulics and hydrology, soil types, vegetation and any sensitive biology in the area, such as endangered species or wildlife habitats.”
After the initial assessment, concept design and preliminary construction estimate, topographic survey data is needed to inform the final design. For this, Tedlock often turns to MEC’s field services department to collect topographic data on the area up and downstream from the exposure as well as the pipeline elevation and data on any other utilities in the area.
“The topographic information is critical for our design work,” said Tedlock. “By pairing this information with historic data from the Division of Water Resources and the United States Geological Survey on how flood prone the area is, we are able to create a well-informed, long-term solution for the pipeline company, so the problem does not recur.”
During the design phase, Blackstone works with the Army Corps of Engineers on the needed permitting. Then, after the design phase is complete and a construction contractor selected, the crew returns to the field to complete construction staking and as-built drawings.
“Not only is accurate data collection essential to an effective and efficient solution to mitigate the pipeline exposure, it is also critical that pipeline companies have accurate records to meet regulatory requirements and inform future pipeline maintenance and modification,” said Lloyd.
Based on the site conditions and environmental considerations, Blackstone’s wetland designers and water resource engineers work to ensure the design accounts for any flora or fauna in the area, and when possible, improve the channel and its capacity.
“We employ Rosgen and APWA natural channel design techniques to stabilize the stream bank, and when possible, improve the habitat,” said Tedlock. “Far and away the worst environmental impact would be a pipeline rupture as a result of the exposure, so we work hard to help pipeline companies prioritize these projects and pre-empt a big environmental issue.”
MEC and Blackstone work on an array of pipeline exposure projects across an eight-state region of the Midwest, an area with a significant number of pipeline transmission lines and large amounts of precipitation.
“No matter what the cost of the barrel of oil is, companies must do the pipeline maintenance and rehabilitation work to preserve their transmission lines and ultimately protect the surrounding area against environmental disaster,” said Lloyd. “The partnership with Blackstone allows each of us to provide services in an area we specialize in and excel at, so pipeline owners and operators receive an efficient, long-lasting solution that protects their assets and protects the environment.”
Little Cedar Creek, Kansas, pictured after a pipeline exposure was corrected.
