Submarine Pipelines

Gas Pipeline Crossing Survey Program

Location: Sacramento/San Joaquin Delta, California

Project Description
The owner required surveys of each of its buried submarine pipeline river crossings in the Delta that required extensive electronic location of the buried submarine pipelines and depth of burial measurements to obtain precise plan and profiles of each crossing from onshore landing to onshore landing. 

L123 worked with an underground utility tracking company to pair an underwater utility tracking antenna with a high wattage toner to locate these pipeline crossings and measure depth of burial at distances in excess of one mile from the toner signal point. This system not only identified the horizontal locations of the pipeline crossings but also provided depth of burial measurements up to 21 feet deep.

Gas Pipeline Crossing Decommissioning

Location: San Joaquin River, California

Project Description
Investigate, plan, permit and perform the decommissioning of three submarine pipeline crossings on the San Joaquin River. The scope of work included provision of all environmental permitting on a turnkey basis, all shore landing terminations, and all underwater terminations and removals.

L123 is capable of planning, permitting and managing major projects on a turnkey basis.

Submarine Pipeline Construction

Location: Long Beach, California

Project Description
THUMS was a consortium comprised of Texaco, Humble, Unocal and Mobil Oil to operate the four islands in Long Beach Harbor for the City of Long Beach and the State of California (now owned by California Resources Corporation). L123 owner, Mark Steffy, contracted to construct a new 12-inch submarine pipeline between Island White and Island Grissom. The 12-inch diameter, 1-mile-long pipeline was to be buried 12-feet below the harbor floor to minimize risks of anchor strikes. The pipeline right-of-way included two 90-degree turns. The project was successfully completed. Mark Steffy designed, built and operated the jetting sled that buried the pipeline in five days.

This project demonstrates L123 ability to perform submarine pipeline construction to perform precise underwater excavation and pipeline burial.