San Vicente Pipeline

About This Project

The San Vicente Pipeline project is part of the Emergency Storage Project, a system of reservoirs, interconnected pipelines, and pumping stations designed to make water available to the San Diego region in the event of an interruption in imported water deliveries.

ABOUT THIS PROJECT - DETAILS

Project Details
The 11-mile San Vicente Pipeline is a large-diameter pipeline connecting San Vicente Reservoir in Lakeside to the Water Authority's Second Aqueduct west of Interstate 15. The pipeline was built in a tunnel at a depth ranging from 50 to 550 feet underground. Tunneling, rather than cut-and-cover trenching, allowed the Water Authority to build the pipeline with fewer impacts to land surfaces and the surrounding communities. During emergencies, the San Vicente Pipeline will operate with other Water Authority facilities to deliver water from San Vicente Reservoir to water agencies in the central and southern areas of the county.

SCHEDULE

Project construction began	2005
Project construction completed	Late 2010

MAP

San Vicente Pipeline: Tunneling Complete

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Construction of the San Vicente Pipeline took place at four tunnel access points along the 11-mile length of the tunnel and pipeline. Three tunneling machines were used to excavate the tunnel. One machine used a rotating cutterhead to break the rock into smaller pieces. The other two used a digging arm equipped with a bucket or rotary cutter to break up the rock. The tunnel was completed in September 2009.

Pipe installation was the other major construction component necessary to complete the pipeline. Steel pipe sections 50 feet long and 8.5 feet in diameter were lowered into the tunnel by a crane at the Central Shaft and San Vicente Portal. A narrow sled hauled two pipe segments at a time inside the tunnel to their location for placement. After the pipe was installed, the contractor placed concrete around the exterior of the pipe to secure it in the tunnel and prevent corrosion. The pipe interior was then lined with a cement mortar lining to further prevent corrosion. The last of more than 1,145 pipe segments was installed in January 2010. Pipe lining was completed in fall 2010. The final testing of the completed pipe was completed in late 2010.

MULTIMEDIA

Photos

San Vicente Pipeline Photographic Tour

The following photographic tour is provided to illustrate construction for the San Vicente Pipeline. Construction activity was concentrated at four tunnel access points, though the majority of the work occured deep underground. The tunnel access points were used to excavate the San Vicente Pipeline tunnel and used to install the pipe segments (see tunnel route map above).

The Water Authority broke ground on the San Vicente Pipeline project in July 2005. The pipeline is a key component of the Emergency Storage Project, a system of reservoirs, interconnected pipelines, and pumping stations designed to make water available to the region in the event of an interruption in imported water deliveries.

Tunnel Excavation Work

The 11-mile-long pipeline was built in a tunnel that was excavated by three tunnel boring machines. Tunneling rather than cut-and-cover trenching meant fewer impacts to land surfaces and the surrounding communities.

Since the pipeline route covered a range of geology from soft to very hard rock material, the contactor used two types of tunneling machines to excavate the majority of the tunnel.

This hard rock tunnel boring machine excavated approximately two miles of the tunnel. The machine was 400 feet long, including trailing gear that supported the tunneling operation.

The boring machine entered the pipeline tunnel at the San Vicente Portal to start its work. An art contest for local school children celebrated the start of the tunneling effort.

The front of the machine was a rotating cutterhead that matched the diameter of the tunnel. As the cutterhead turned, hydraulic cylinders gripped the rock and a second pair of hydraulic cylinders pushed the cutters into the rock.

For other portions of the tunnel, a digger shield tunneling machine was used. Here, a crane lowered the digger shield machine into the Central Shaft.

The digger shield used a pick and paddle apparatus at the front of the machine to excavate approximately eight miles of the tunnel.

As the machines advanced underground, concrete segments were erected behind it to stabilize and secure the tunnel walls.

The rock and dirt material excavated by the tunneling machines was removed from the tunnel in haul trains.

Some short sections of the tunnel contained rocks too hard for the tunnel machines to excavate, so controlled blasting was needed.

This is the view inside a portion of the excavated tunnel from the Slaughterhouse Shaft. The tunnel was 12 feet in diameter.

After more than four years of tunnel excavation work, a significant milestone was achieved in September 2009 when crews completed all 11 miles of tunneling for the pipeline.

Pipe Installation Work

Pipe installation was the second major construction phase of the project. Steel pipe sections were 50 feet long, 8.5 feet in diameter and weighed 17 tons. More than 1,000 pipe segments were used to build the pipeline.

Some of the pipe segments used to build the pipeline were delivered and stored near the San Vicente Portal.

Pipe segments were moved into the tunnel by a crane at the Central Shaft and San Vicente Portal locations.

The pipe entered the tunnel from the bottom of the shaft. When each segment reached its destination inside the tunnel, crews precision-fit the pipe to the adjacent pipe segment while it was braced securely against the tunnel walls.

Once pipe was installed in the tunnel, crews pumped in grout to fill the space between the pipe exterior and the tunnel walls. This ensured the steel pipe stayed in place and was protected from corrosion.

A grout plant at the Central and West shafts produced grout on site. The system pumps grout into the tunnel through a pipe and hose system.

To protect the pipe during the grout work, eight-foot-tall aluminum beams were placed in a crossed position inside the pipe.

The final step for pipe installation was applying a cement mortar lining to the inside of the pipe to further protect it from corrosion. A wire brush tool at the end of this rotating device cleaned the pipe interior before the mortar lining was applied.

Water in the pipeline will be moved with assistance from the San Vicente Pump Station, located near the San Vicente Portal. In an emergency, the pump station will be able to move approximately 300 million gallons of water each day from San Vicente Reservoir.

From the pump station, water will be pumped up to the new surge control facility on a hilltop near San Vicente Dam. The surge control facility enables water to flow by gravity through the San Vicente Pipeline to the Water Authority’s Second Aqueduct, 11 miles away. It also protects the pipeline in case of a sudden pressure surge in the pipe.

Now complete, the pipeline will operate with the San Vicente Pump Station and Surge Control Facility to deliver water from San Vicente Reservoir to the southern portion of the county in an emergency.

Videos

Tunneling Breakthrough

The September 21, 2009, breakthrough completing the 11-mile-long tunnel for the pipeline was documented by TunnelTalk.com. Click here to view the video.

Other

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PUBLICATIONS

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