Posted on February 28, 2013

PG&E Begins High-Tech Survey of EntireTransmission Pipeline System

Over the next few months, PG&E and contract crews will be doing a high-tech mapping survey of all of its 6,750-mile gas transmission pipeline system.

PG&E's Parker Geisinger locates the above-ground marker and maps the location of the natural gas transmission pipeline using high-precision Global Positioning System (GPS) mapping technology

Using highly precise GPS mapping tools, the crews will survey areas above transmission pipelines, called utility rights-of-way, which are located along residential, commercial, industrial and agricultural properties. This “centerline” survey activity will locate, mark and map the center of the pipeline, and check the area above the pipeline for any structures or vegetation that could interfere with PG&E’s ability to maintain, inspect and safely operate the pipeline.

The effort is part of PG&E’s ongoing work to improve the safety of its gas operations.

“This survey work provides another example of our emphasis on public safety,” said Joe Medina, director of PG&E’s Transmission Process and MAOP Validation department within Gas Operations. “Better tools, better information and better access to our pipelines benefits everyone.”

The end result:

  • A more precise pipeline map that will allow PG&E to better serve customers, enhance its ongoing pipeline safety programs and work more efficiently with first responders.
  • Recording the exact GPS location of the center of a pipeline will ultimately enable PG&E to use-state-of-the-art software tools to better maintain the pipeline system.
  • This will be important whether someone is checking on a pipeline in a computer system or doing a leak survey, or patrolling in the field, either on foot or in the air using a helicopter or airplane.

More than a dozen crews started the work in December of 2012. The goal is to get the entire system surveyed this year.

PG&E's Parker Geisinger and Nguyen Chau transmit the GPS data to the central computer

Much like its electric transmission towers and lines, PG&E’s natural gas transmission pipelines are often found on rights-of-ways or easements on private property. Those rights-of-way assure that PG&E has ready access to its pipelines for safety reasons, including maintenance, testing and monitoring the pipelines. Keeping these rights-of-way accessible is a shared responsibility between PG&E and landowners.

An estimated 15,000 PG&E customers or tenants will have their properties surveyed.

Here’s how it works: About two weeks before the survey crews arrive, a property owner or tenant will get a letter in the mail from PG&E that explains the work. Then, when the crews arrive they knock on doors to let people know they’re about to start their work.

Survey crews typically include two or three workers. The first crew locates and marks the pipeline using yellow chalk paint, small yellow flags or temporary yellow markers. Then, other workers follow the trail, using devices to record pinpoint GPS data on the pipeline location every 50 feet or so. At the end of the day that information is downloaded and put into a computerized map.

For both PG&E and its customers, safety is paramount. As it moves to rigorously survey rights-of-way for its transmission lines in Northern and Central California, PG&E has pledged to work closely with individual property owners.

If something is found that prevents access to the pipeline, PG&E will work individually with those customers to alleviate the issue.

During the survey, crews will make brief property visits to locations where the pipeline runs underground. The process will include contacting owners in advance.

That’s what happened in San Leandro after Tom Griffin learned that a large tree, two concrete pads and a garden shed were obstructing the pipeline right-of-way in his yard.

Expecting the worst, as he later explained in an email, he was taken by surprise during a meeting with PG&E representatives.

“The conversation had a very cordial and helpful tone,” he wrote. “They were discussing where they could move the shed, how they could build concrete pads in other parts of the yard, how they could re-do the pathways, and how they could replace the tree.”

His surprise turned to realization.

“I understood what was happening. PG&E was stepping up to the plate and doing what was needed to restore the easement. Despite the fact that we were the ones in the wrong, PG&E was the one taking the initiative to make it right. And they did make it right, in a big way.”

It is a sentiment shared by Griffin’s neighbor. Her experience prompted a hand-written letter: “I say thank you to you and your crew every time I walk out in my back and side yard.”


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"PG&E" refers to Pacific Gas and Electric Company, a subsidiary of PG&E Corporation.
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