New 26-Mile Pipeline Installation Project

GTS provided engineering & design for 26 miles of new pipeline installation in two phases over a two-year period; Phase I (2017) was approximately 12-miles in length with one mainline valve station and one pressure limiting station (PLS). Phase II (2016) was approximately 14-miles of 30-inch with one mainline valve station. Several construction methods were utilized for construction, including direct bury, six guided auger bores and 17 horizontal directional drills (HDDs).

A project of this magnitude and complexity encounters many engineering and construction challenges. The project team had to work through planning, land acquisition, engineering, high ground water levels, environmental, permitting and construction impacts. Within its 26 miles, the pipeline route crossed; through three county jurisdictions, the Sacramento River, the Yolo Bypass, California State Highway 70/99, numerous irrigation canals, several nature conservancies, designated wetland areas, agricultural areas and areas designated for commercial and residential development.

The engineering design of the pipeline was constantly evolving to address the permit requirements as land settlement agreement conditions were negotiated. Engineering design accounted for planned developments adjacent to the proposed route. Phase I is currently located in a Class 1 location, but was designed for Class 3 to account for 35,000 homes and several large commercial centers planned to be built in the coming years. The design also needed to mitigate the potential for flooding and address a significant volume of ground water to be handled, treated and discharged.

Communication and document control for a project this size is crucial. With multiple prime contractor spreads, four HDD rigs and one auger crew all working concurrently, RFI’s were consistently being submitted and evaluated. Engineering and construction worked closely to ensure the latest drawing revisions incorporating approved changes were in the field to construct the line and ensure quality control practices were rigorously followed. As a result of the increased capacity and flexibility afforded by the new pipeline, the client was able to cancel several planned capacity and uprate projects.