Designing and Permitting an Oil Pipeline Through Complex Terrain
When oil companies needed to provide safe, economical, over-land transport to bring crude oil from offshore platforms along California’s central coast to Los Angeles refineries, they called on Tetra Tech Rooney.
Tetra Tech designed the 130-mile Pacific Pipeline System, coordinated a permitting process, and provided construction management services. Tetra Tech's design approach and state-of-the-art leak detection system helped the project pass rigorous reviews and obtain approvals.
The pipeline fell under the jurisdiction of both state and federal agencies. It passed through 13 municipalities and crossed diverse terrain.
Tetra Tech's approach was determined to be environmentally superior to 15 alternatives studied by the California Public Utilities Commission and U.S. Forest Service, according to the joint state/federal Environmental Impact Report/Environmental Impact Study (EIR/EIS).
Mitigation measures from the EIR/EIS that Tetra Tech addressed during construction included erosion control, stormwater pollution prevention, landowner communication and outreach, cultural resources protection, fire prevention, and utility protection. Project managers also took advantage of the system’s integrated, high-speed fiber optic communication capabilities to offer up to 35 computer centers in disadvantaged communities along the pipeline route.
To meet the project’s safety requirements, Tetra Tech established multiple redundancies in the monitoring and emergency shutoff systems. Materials selection provided additional security.
- Nitrogen-actuated block valves provide emergency isolation capabilities and will function even if an earthquake disrupts the system’s electrical power
- An additional 20 check valves limit backflow in case of a line break
- A 20-inch pipeline is designed to flex in an earthquake
- The system checks the line four times per second, relaying information to a control center staffed around the clock
To address challenges posed by the varied terrain, the project was divided into segments based on land type and construction challenges. Tetra Tech used GIS mapping and GPS systems to keep the pipeline true to its proposed route.
The project employed horizontal directional drilling at 10 crossings that passed under active landslides and busy urban highways, making construction possible in areas where traditional methods could not be implemented.
- System leak detection capabilities higher than industry norm
- Complex multiyear, multiagency permitting process completed
- Horizontal directional drilling allow project to proceed through dense urban areas
- Established 35 computer centers for communities along project route