San Vicente dedication

The San Vicente Pipeline Tunnel has been completed and was dedicated on 19 January in San Diego County, California, USA.

Jacobs was prime design consultant for this part of the USD 1.5bn Emergency Storage Project, which was carried out by the San Diego County Water Authority (SDCWA).

The 17km long, 2.6m diameter pipeline drive stretched from Lakeside to Mira Mesa and connected the San Vicente Reservoir to the Water Authority’s Second Aqueduct. The intention was that this 757,000-litre per minute capacity pipe would help the county’s emergency water distribution in the event of a disaster.

Tunnelling began in 2005 and required three access shafts and one portal along the route. Three TBMs – one hard rock machine and two digger shields – were engaged around the clock on different sections of the drive. The last breakthrough occurred in September 2009.

Following excavation, the construction teams placed 1,145 of the 15m, 15.4-tonne steel pipe sections into the tunnel and encased them in cellular concrete on the outside for structural protection and lined the inside with cement mortar to resist corrosion.

Testing in December revealed the pipeline to be fit for service.

“One unique operational aspect of the pipeline is that it provides SDCWA with a bidirectional flow capability. When imported water is available, the pipeline can convey water from west to east to fill San Vicente Reservoir. It can also be used to convey water from the reservoir to the west when emergency conditions require the stored water,” said Jacobs.