Pacific Gas & Electric
When an excavation project to recover a gas line inspection tool endangered a historic redwood tree, Davey Resource Group helped ensure the recovery and compliance with relevant ordinances all while preserving the future health of the tree.
The Challenge
When a pipeline inspection gauge (PIG) became stuck in a pipeline in Ukiah, California, it became Pacific Gas and Electric’s (PG&E) mission to recover the tool, which required excavation of the area around the pipe and extraction of the section where they suspected the PIG was trapped. The PIG had to be removed for safety reasons, as the high pressure it could cause in the transmission line had the potential to cause an explosion.
A redwood tree in the planter above the pipeline was a designated landmark tree, meaning excavation could not be performed within a certain distance of the tree’s dripline without an emergency exemption. Excessive damage to the roots could also lead to the failure of the redwood. Davey Senior Consulting Utility Forester Jillian Keller’s oversight was vital to ensure project success with minimal compromise to the tree’s health.
The Solution
Jillian stayed on-sight for the excavation, ready to make the call for emergency exemption should the tree be affected by the dig. Unfortunately, when the dripline and excavation parameters were marked, there was significant overlap. An emergency exemption was obtained and the project could proceed with caution.
Jillian instructed the crew to trim the roots that were damaged in the excavation in a way that facilitated healing. As a result, the project continued without hitting any structural roots and was back-filled as soon as possible so as to not disrupt the soil hydrology.
The Results
The section of pipe that was removed was shipped to a processing plant in Texas to extract the PIG, and Jillian’s attention to detail and initiative safeguarded the redwood tree against unnecessary damage. Ultimately, the client was satisfied with the outcome of the project.
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