SLR River pipeline work now complete

The San Diego County Water Authority has deemed work on the relining of three SDCWA pipelines along the San Luis Rey River as complete. The work, which has been visible over the past few months, was to be done early in the SR76 East widening project.

A unanimous CWA board vote May 28 approved the Notice of Completion for the project while authorizing the release of funds to contractor L.H. Woods and Sons, Inc., which had been held in retention.

The CWA's Second Aqueduct includes Pipelines 3, 4, and 5. Pipelines 3 and 5 currently convey untreated water along the San Diego Aqueduct. Pipeline 4 conveys treated water. (The master plan update adopted by the CWA in March 2014 includes switching Pipeline 3 to treated water and Pipeline 4 to untreated water, which would increase the CWA's untreated water conveyance capacity, during the 2020-25 timeframe.)

Pipeline 3 is a welded steel pipe 72 inches in diameter, Pipeline 4 is a prestressed concrete cylinder pipe with a 90-inch diameter, and Pipeline 5 is a prestressed concrete cylinder pipe 96 inches in diameter.

Several pipeline failures in the early 1990s resulted in the CWA's 1992 creation of the Aqueduct Protection Program for pipeline constructed prior to 1984. The program included an initial assessment which determined the estimated remaining service life of pipeline portions and the frequency of internal inspections which are used to adjust the replacement and relining schedules.

Pipeline 4 was scheduled to be rehabilitated during fiscal year 2017. However, the widening of State Route 76 between South Mission Road and Interstate 15 includes an alignment which will cross over the CWA's Second Aqueduct approximately half a mile west of Interstate 15.

The planned bridge over the Second Aqueduct will provide approximately eight feet of vertical clearance between the bottom of the bridge and the ground. The new bridge crossing will hinder the CWA's ability to maintain, repair, or replace the pipelines under the bridge, so an agreement to reline the pipelines was negotiated by the CWA, the California Department of Transportation, and the San Diego Association of Governments (which has been delegated funding discretion for state highways). The relining is expected to extend the service life of the pipelines by approximately 75 years and the expected service life of the new Caltrans bridge is 75 years, so the pipeline relining will likely eliminate the need for future work during that time.

Combining the longer portion of the Pipeline 4 relining with the portion necessitated by the new Caltrans bridge provided an economy of scale with the relining while also reducing the frequency and number of pipeline shutdowns and completing the rehabilitation of that part of Pipeline 4 ahead of schedule. The CWA issued the contract with Caltrans providing reimbursement of up to $6.1 million for the portion of the pipeline impacted by the new bridge crossing and the CWA paying for the remaining costs. The CWA is working with Caltrans on the final reimbursement payment. Caltrans and the CWA also agreed to exchange mitigation land currently owned by Caltrans as compensation for the CWA property required for the Highway 76 project.

In July 2014, the CWA board authorized general manager Maureen Stapleton to enter into a $9,750,000 construction contract with L.H. Woods and Sons, Inc., of Vista and authorized Stapleton to enter into a professional services contract with Pure Technologies, Inc., for up to $385,000 for acoustic fiber optic modification along the segments which will be relined. Six administrative change orders, three design modifications, and four change orders due to actual site conditions created a final contract amount with L.H. Woods and Sons of $9,464,674. The change orders did not affect the completion date.

The CWA aqueduct easement precedes the Caltrans highway easement, making it necessary for the CWA to grant Caltrans a right of entry permit to construct the bridge crossing, but Caltrans was not given that access until the pipeline relining work was completed. The work needed to be complete by May 1 to avoid delaying the Caltrans schedule; the pipeline rehabilitation began in September 2014.

The work relined 3,372 lineal feet of Pipeline 4, 316 lineal feet of Pipeline 3, and 288 lineal feet of Pipeline 5. The relining of Pipelines 3 and 5 is within the new Caltrans easement limits while the Pipeline 4 relining began north of the existing State Route 76 and ended south of the San Luis Rey River.

The CWA uses an acoustic fiber optic system to monitor pipeline conditions; the acoustic fiber optic system also calculates the rate of decay in pipeline segments and allows CWA staff to determine the remaining service life. Pure Technologies removed and re-installed approximately 12,000 feet of the fiber optic system in conjunction with the relining.

L.H. Woods and Sons has no open claims. During construction five percent of the total contract amount was retained in accordance with the contract terms to be released 60 days after the notice of completion. L.H. Woods and Sons provided a performance bond which will remain in effect for a two-year warranty period.