Relining of pipelines crossing Hwy. 76 in 2016-17 Aqueduct Operating Plan

The San Diego County Water Authority (CWA) annually develops an Aqueduct Operating Plan which was presented to the CWA's Engineering and Operations Committee during the committee's June 25 meeting, and the CWA plans to shut down its three Second Aqueduct pipelines which cross State Route 76 for inspection of the new relining.

The presentation, which was a non-voting item for the committee and full CWA board, covered the Aqueduct Operating Plan (AOP) for the fiscal year beginning July 1, 2016, and ending June 30, 2017. The AOP is used as a planning element to optimize the delivery, treatment, and storage of water in the CWA's service area by facilitating coordination and communication among the CWA, its member agencies, and the Metropolitan Water District of Southern California (MWD).

The AOP includes a summary of scheduled shutdowns or outages which impact delivery of treated or untreated water, pump station operating schedules, member agency major maintenance information, and the production and consumption of energy for CWA hydroelectric facilities, pump stations, and the CWA's treatment plant.

The plan utilizes information obtained from member agencies, historical delivery data, aqueduct constraints, and shutdown plans. A shutdown is defined as a temporary closure of a large portion with regional effects while an outage is defined as a more localized portion closure and impact.

Currently five CWA pipelines carry water along the San Diego Aqueduct from MWD's Lake Skinner facility in Temecula. The First Aqueduct consists of Pipelines 1 and 2 and the Second Aqueduct has Pipelines 3, 4, and 5. Pipelines 1, 2, and 4 convey treated water while Pipelines 3 and 5 deliver untreated supply. The aqueduct system has a treated water capacity of 650 cubic feet per second (cfs) and an untreated water capacity of 780 cfs.

The alignment for the widening of State Route 76 between Mission Road and Interstate 15 crosses the CWA's Second Aqueduct about half a mile west of I-15. The pre-construction work for the road included relining segments of the three pipelines impacted by the new bridge, and an additional portion of Pipeline 4 which was scheduled for near-term rehabilitation was also relined.

The shutdown for the inspection of Pipeline 3 at the San Luis Rey siphon is scheduled to take place Nov. 6 to 15, the shutdown for the Pipeline 5 inspection is slated for Jan. 8 to 17, and the shutdown for the Pipeline 4 inspection is targeted for Feb. 17 to 26. Because Pipeline 4 is the Second Aqueduct's only treated water pipeline, the February shutdown will place four Rainbow Municipal Water District and three Fallbrook Public Utility District connections out of service during that time.

The Weese Water Treatment Plant is owned by the City of Oceanside but physically located in Bonsall. Upgrades to the Weese treatment plant will take place in January and February.