Pacific Gas & Electric Co. is on the lookout to clear any trees or structures sitting on top of its network of natural-gas pipelines in Fresno, and throughout California.
The utility company last year began a precision survey, using GPS technology, to map out about 6,750 miles of underground transmission lines and the easements above them.
At the same time, crews identified properties where trees or structures encroached on those easements, creating potential problems for workers to get to the pipeline in case of maintenance or emergency.
PG&E's easements extend 10 feet in each direction from the center of the pipeline, and there aren't supposed to be any structures or trees within that area above the pipeline.
Now, PG&E is getting ready to start work on removing any obstructions, whether on private property or in public rights of way, including under streets or roadway medians, said Ivan Altamura, director of the utility's Pipeline Pathways project.
The mapping and easement project is only for PG&E's transmission pipelines, which carry natural gas at pressures above 60 pounds per square inch. It does not include lower-pressure distribution lines or service lines that actually provide gas to individual customers.
The easement inventory represents one step that PG&E is taking to increase the safety of its natural-gas pipelines in the wake of a deadly 2010 pipeline explosion in San Bruno. Eight people died in the blast, which happened in a residential neighborhood and destroyed or damaged dozens of homes.
Safety is fueling the urgency in the pace of PG&E's easement-clearing efforts. In addition to the danger to homes or other structures above the line if an accident happens, a tree with roots that have grown around a pipeline could cause serious damage to the line if it topples or is uprooted in a storm or high winds.
"We don't want a situation where we have to get into a pipeline for maintenance or an emergency situation and there's a tree that has to be taken out before we can get to it," Altamura said.
PG&E crews have established three priority levels for encroachments within pipeline easements:
- Priority 1 encroachments include habitable structures sitting directly above a pipeline.
- Priority 2 issues include a nonhabitable structure or a tree directly above a pipe.
- Priority 3 encroachments include an uninhabited structure or a tree that sits within the easement but not directly above a pipe.
"You might have a hot tub or a storage shed or a tree that could be a Priority 2 or Priority 3 encroachment," Altamura said.
Fresno was one of the first cities where the pipeline survey has been finished, and Altamura said there were only a couple of Priority 1 problems that already have been resolved at the utility's expense.
One was a storage unit, and another was where a business was doing some of its operations above a pipeline, "and those were already remedied," Altamura said.
For Priority 2 and 3 problems, the utility is working with property owners to remove and replace trees or to relocate any structures that are in the way.
"If we have a situation where we can't move something, we'll work with that property owner to compensate them for that loss," Altamura said. "Every property is unique and different."
PG&E has identified more than two dozen structures that will need to be cleared from easements in Fresno and Clovis.
When individual property owners have an encroaching structure or tree, PG&E will directly contact them by mail and in person to work out a solution, Altamura said.
Along streets or other public areas, the utility will be sending notices to residents within a 500-foot area to let them know about the work to remove trees in the area. Where city-owned street or median trees are removed, PG&E is arranging to replace each with two new trees.
Altamura acknowledged that while property owners are responsible for knowing if there is a utility easement on their land, PG&E "has not adequately monitored its right of way, and then you have situations where encroachments have occurred over the top of the pipe."
"That," he added, "is why we are paying for the remedies to the situation."
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