Prepare for Severe Floods, Pipeline Operators Reminded

The Pipeline and Hazardous Materials Safety Administration's new advisory bulletin for owners and operators of gas and hazardous liquid pipelines says the Yellowstone River spill that began July 1 shows the risks.

The federal Pipeline and Hazardous Materials Safety Administration has issued another advisory bulletin urging owners and operators of gas and hazardous liquid pipelines to take nine actions to prepare their facilities for severe floods. The bulletin says the ExxonMobil Pipeline Co. spill in the Yellowstone River that began July 1 shows the risks of such floods, noting that the spill remains under investigation.

ExxonMobil's latest update says active cleanup activities are focused on 19 miles of the river, under the direction of EPA and the Montana Department of Environmental Quality, with reconnaissance and evaluation continuing for a stretch of 222 miles. Other agencies involved in the spill response are the U.S. Department of the Interior; PHMSA; the U.S. Coast Guard; Montana Fish, Wildlife and Parks; Yellowstone County Disaster and Emergency Services; and Yellowstone County commissioners.

Severe flooding can affect safe operation of a pipeline and require corrective action under section 192.613(a) of the Pipeline Safety Regulations (49 CFR parts 190-199), PHMSA points out, citing eight pipeline failures in October 1994 caused by major flooding on the San Jacinto River near Houston and also the Yellowstone spill. The advisory recommends that operators take these actions:

1. Evaluate the accessibility of pipeline facilities that may be in jeopardy, such as valve settings, which are needed to isolate water crossings or other sections of a pipeline.
2. Extend regulator vents and relief stacks above the level of anticipated flooding, as appropriate.
3. Coordinate with emergency and spill responders on pipeline location and condition. Provide maps and other relevant information to such responders.
4. Coordinate with other pipeline operators in the flood area and establish emergency response centers to act as a liaison for pipeline problems and solutions.
5. Deploy personnel so they will be in position to take emergency actions, such as shutdown, isolation, or containment.
6. Determine whether facilities that are normally above ground (e.g., valves, regulators, relief sets, etc.) have become submerged and are in danger of being struck by vessels or debris; if possible, such facilities should be marked with an appropriate buoy with Coast Guard approval.
7. Perform frequent patrols, including appropriate overflights, to evaluate right-of-way conditions at water crossings during flooding and after waters subside. Determine if flooding has exposed or undermined pipelines as a result of new river channels cut by the flooding or by erosion or scouring.
8. Perform surveys to determine the depth of cover over pipelines and the condition of any exposed pipelines, such as those crossing scour holes. Where appropriate, surveys of underwater pipe should include the use of visual inspection by divers or instrumented detection. Information gathered by these surveys should be shared with affected landowners. Agricultural agencies may help to inform farmers of the potential hazard from reduced cover over pipelines.
9. Ensure that line markers are still in place or replaced in a timely manner. Notify contractors, highway departments, and others involved in post-flood restoration activities of the presence of pipelines and the risks posed by reduced cover.

If a pipeline has been damaged, is shut in, or is being operated at reduced pressure as a precaution because of flooding, the operator should advise the appropriate PHMSA Regional Office or state pipeline safety authority before returning the line to service, increasing its operating pressure, or otherwise changing its operating status, PHMSA stated.

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