Construction of Gas Pipeline Relied Heavily on HDD to Minimize Environmental Impacts

Minimal Impact, Maximum Outcome
By Ron Walker | November 2009 Vol. 64 No. 11
Successful hammerjack bore connecting to area previously trenched. Photo: Travis King.

In addition to the regulatory agencies involved with the permitting, the following organizations also contributed to the development of the project: the County of Sacramento, the city of Elk Grove, and the conservation organization the Nature Conservancy.

Final element
The final element of the Line 108 Replacement Project involves removing a suspension bridge constructed by PG&E in the 1930s to support the original pipeline where it crossed the Cosumnes River. PG&E, which owns the bridge, was asked by the Nature Conservancy, which owns part of the Cosumnes River Preserve, to remove the span to help prevent trespassers from reaching an island with sensitive habitat.

The approximately 630 foot long structure is supported by two piers and two anchor blocks, one of each of which is located on either side of the river. Along with the bridge, PG&E is removing the north anchor block and north pier to 1 foot below the natural grade and backfilling the area. Because the bridge originally had been painted with lead based paint, special measures must be taken during its demolition to prevent the introduction of contaminants into the environment. Work on the bridge removal began in June 2009 and is scheduled to be completed by the end of July 2009.

Approximately three years were spent completing the environmental reviews and obtaining the various permits required for the project. Overall, the project team negotiated approvals on 19 local, state and federal permits and 98 land owner/purchase agreements. Given the number of environmental hurdles, this project succeeded in large part because of the cooperation of the Bureau of Land Management, the U.S. Fish & Wildlife Service, the California Department of Fish & Game, and the Nature Conservancy. Within PG&E, Michael Gunby, the principal land planner for the utility, led the efforts related to the environmental aspects of the project.

Pipeline construction, meanwhile, required only three months. With more than 82,000 man hours of construction, the workers achieved triple zero safety performance.