While oil spills and pipeline leaks grab headlines, their notoriety is generally a sign of the rarity of accidents. The accidents that do occur can be devastating, even when in relatively small quantities – that cannot be ignored. Still, pipelines carry enormous quantities of hazardous materials and do so more effectively than any other method of transportation currently available.

In determining whether pipelines are safe, one unit of analysis is water crossings. These are likely to be environmentally vulnerable areas, and if pipeline incidents regularly occur there, it is a severe concern and a significant mark against the safety record of pipelines.

The data from the Pipeline and Hazardous Materials Safety Administration (PHMSA) indicates that for inland areas, fewer than one percent of incidents occur at or even near bodies of water. In 2013, PHMSA recorded 18,136 inland pipeline water crossings. At those crossings, across the entire country in a 21-year period, PHMSA recorded only 20 incidents.

Three years later, another report from PHMSA put the water crossing statistic at one percent of all incidents. This higher percentage of incidents included those issues happening near water, not just at the water itself.

Importantly – and keen observers will note – these studies were across all pipelines in the U.S. regardless of size. Recording incidents for the whole country also means different climates and environments. This raises several questions worth considering, and areas of analysis for how we might achieve safer pipelines to prevent harm to the environment and vulnerable ecological areas.

It is generally bad analysis to take general or aggregate data and apply it to a particular subject. In a room with an average income of $100,000, simply pointing to a person and asserting they surely earn exactly $100,000 is not likely to be accurate. Likewise, many would say that pointing out that across the entire country and across two decades, very few pipeline incidents occurred at water crossings, and further saying that at some particular or proposed pipeline we should not worry about a water crossing incident, this is the same and is bad analysis.

I would agree, except for unlike the income earnings in a room example, one variable is changing over time: innovations in pipeline safety.

The figures of less than one percent of incidents occurring at water crossings are old data. In the meantime, materials, technology, techniques, and regulations have improved such that pipeline incident rates have fallen significantly. When pointing to a specific pipeline now, there is a better chance it will be safe because of both background statistics on pipeline safety and the arsenal of technology that is added to the industry every year. Yes, a general rule still does not perfectly speak to a particular circumstance.

In 2016, industry experts identified “river crossing/river behavior sensor to detect erosion” as a potential industry gap in need of addressing. In fact, it is a decades-long problem well acknowledged in existing research. While extensive standards, guidelines, and best practices exist for properly planning, building, and completing projects, ultimate pipeline safety includes operation and monitoring, where technology plays an outsized role.

Among potential solutions are constant monitoring through in-ground fiber sensing networks as well as leveraging sensing and remote and autonomous methodologies. In fact, numerous sensors and techniques are commercially available, even while new technology is developed and tested regularly. Adding in satellite and drone imagery further strengthens the monitoring capabilities, and with the right technology can see through the water. Finally, additional barriers and levees can be constructed to reduce erosion as well as encasing pipelines. Is this still considered a gap by the industry? While “river crossings–river behavior, sensors to detect erosion and slides that may cause damage” was mentioned as recently as 2018 by the Common Ground Alliance (CGA) in its Technology Advancements and Gaps in Underground Safety (Technology Report), the issue has not appeared in any subsequent annual CGA Technology Reports. Similarly, while the National Transportation Safety Board (NTSB) has included “improve pipeline leak detection and mitigation” and “enhance pipeline safety” in its “Most Wanted” list three times since 1990, the safety organization does not contemplate water crossings or identify them as a gap. NTSB has instead pointed to industry construction standards or federal rules already in place.

But what about non-natural threats? While erosion is bound to happen if the right precautions are not put into place, monitoring can provide advanced notice before this becomes an issue that threatens the pipeline’s integrity. Direct threats from third parties remain highly relevant for the underwater pipeline sector. Sensors and monitoring can notify immediately of a pipeline strike, but they are unlikely to prevent the strike or provide the advanced notice needed to stop a third-party from interacting with the pipeline.

A 20-year timespan incorporating U.S. Coast Guard, National Transportation Safety Board (NTSB), and PHMSA data indicates 118 pipeline strikes in marine environments from ship interactions. This is more expansive than the inland figure above, because it includes coastal environments.

This is where marine locating within the damage prevention industry is critical. Subaqueous pipelines in marine environments may include inland rivers, streams, or lakes, as well as coastal and oceanic contexts. Across this spectrum, risks are imposed by scrapes with the bottom of marine vessels from private to commercial boats and ships, anchor dragging, dredging, pile-driving, and more.

The marine locate and excavation process is designed to avoid these damages and helps keep pipelines safe. It requires high awareness and use of the 811 system, including reliance on virtual processes like electronic white-lining to pre-mark and notify about intent to excavate in an aquatic environment and it requires precise and up-to-date mapping by pipeline operators shared with other relevant stakeholders.

As we look at pipeline water crossings, we can have confidence that they are already safe because of high engineering standards, regulatory requirements, innovative technologies, and sensors to collect and process data. Remaining threats like erosion and third-party damage can be effectively mitigated or prevented. More can and should be done to promote safety in this sector, including more research.

Written by Benjamin Dierker, Executive Director


The Alliance for Innovation and Infrastructure (Aii) is an independent, national research and educational organization. An innovative think tank, Aii explores the intersection of economics, law, and public policy in the areas of climate, damage prevention, energy, infrastructure, innovation, technology, and transportation.