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Pipeline relining is an efficient technique that extends the lifespan of pipes while minimizing costs and impacts to nearby communities. Photo: Water Authority

Innovative Pipeline 5 Relining Completed

San Diego County Water Authority crews completed relining a segment of Pipeline 5 in Fallbrook and San Marcos in late July, reaching a milestone in a strategic, multi-decade pipeline relining program. The 2.3-mile segment of Pipeline 5 was relined with new steel liners that are planned to last for more than 75 years.

The proactive pipeline relining program is a crucial part of asset management efforts that improve the reliability of San Diego County’s water supplies.

30-year pipeline relining program

Since the relining program began in 1991, nearly 47 miles of pre-stressed concrete cylinder pipe have been rehabilitated. This constitutes more than half of the total PCCP in the Water Authority system. The remaining 35 miles are expected to be rehabilitated by 2027.

The Pipeline 5 project was conducted in eight segments to minimize impacts to the nearby communities of Fallbrook and San Marcos.

Proactive measures to protect infrastructure

Pipeline relining is an efficient technique used on long stretches of pipelines. It involves inserting new steel liners into the existing pipes. The new liners can extend the lifespan of the pipe by several decades.

“Relining our existing pipes is quicker and more cost-effective than excavating, removing and replacing an entire pipeline,” said Gary Olvera, senior construction manager at the Water Authority. “In partnership with our member agencies, the Water Authority has developed an efficient and proactive plan to ensure continued water supply reliability for the entire region.”

New steel liners can extend the lifespan of a pipe by several decades. Photo: Water Authority

New steel liners can extend the lifespan of a pipe by several decades. Photo: Water Authority

Innovative technique to minimize impacts

To access Pipeline 5, crews excavated dirt to create eight 25-foot by 60-foot access portals spaced roughly 525 to 2,500 feet apart. During construction, crews eliminated two of the originally planned portals, helping save more than $217,000. Most of the work was then performed underground, inside the pipe.

Once the new liner was installed, the joints were welded together. Then, each new steel liner was coated with a cement mortar lining. Finally, the portals were backfilled, the pipeline was disinfected, and the pipe was put back into service.

A welder works inside the pipe to connect the new joints. Photo: Water Authority

A welder works inside the pipe to connect the new joints. Photo: Water Authority

Maintaining regional water supply reliability

Large-diameter pipelines operated by the Water Authority and its 24 member agencies extend approximately 310 miles to convey water throughout San Diego County.

Approximately 82 miles of the pipelines are pre-stressed concrete cylinder pipes. These types of pipes were installed between the early 1960s and late 1980s and some are nearing the end of their service life.

By relining the pipes ahead of time or conducting timely repairs with the latest technology, the Water Authority and its member agencies avoid pipeline failures and improve the reliability of future water supplies.

The $24 million Pipeline 5 Relining Project in Fallbrook is expected to conclude in summer 2019. Photo: San Diego County Water Authority

Pipeline 5 Upgrades Begin in Fallbrook

A $25.3 million Pipeline 5 relining project is under way in North County to improve the reliability of the San Diego region’s water delivery system. The project involves rehabilitating approximately 2.3 miles of one of the San Diego County Water Authority’s regional wholesale water pipelines in eight segments along a 9.5-mile stretch through the community of Fallbrook.

Construction work will be done in phases and completed in summer 2019. When finished, the Pipeline 5 Relining Project will help extend the service life of this vital piece of infrastructure for more than 75 years. Generally, relining construction rehabilitates segments of pipelines based on their age and the need for improvements.

Relining process advances in well-planned stages

Construction activities in Fallbrook began September 19 with the installation of protecting fencing, establishing an entrance to the construction area, and clearing the site of all vegetation and debris for safety. The relining itself will begin in November.

In broad terms, the relining process begins with dirt being excavated to create an access portal or work area. The construction crews will conduct most of the work underground, inside the pipe. They will access the pipe by excavating, establishing, and entering the pipeline through nine access sites, or portals. The portals will be 25-foot by 60-foot excavated pits, spaced approximately 525 to 2,500 feet apart. At each portal site, 40 feet of existing pipe is removed to permit access inside the pipe to install relining materials.

The work involves removing 20-foot sections of old concrete pipe at each portals. Then, new steel liners are inserted into the existing pipe using a specialized pipe cart. Liners are installed into the entire pipe section. Once installed, the joints of the liner pipe are welded together. Each new steel liner is coated with a cement mortar lining. Finally, portals are backfilled and — after pipeline disinfection — the pipe is ready to be put back into service.

Community kept informed about project’s progress

Much of the construction work associated with the project is in Water Authority rights-of-way. Some portals within the unincorporated San Diego County portion of the alignment will be in undeveloped areas.

As people living and working in the area begin to see the activity, project team members will be available to address questions or concerns. Contact information including 24-hour phone numbers, email contacts, and website links are posted on nine informational signs along the construction route. Construction workers on site will also have contact information to pass out on request.

For more information, residents can call the 24-hour project information line at (877) 682-9283, ext. 7009 or email . A representative from the project team will respond within one business day.

Pipeline upgrades ensure safe, reliable water supplies

The Water Authority’s large-diameter pipelines extend approximately 310 miles to convey water throughout western San Diego County. Approximately 82 miles of these pipelines were installed between the early 1960s and late 1980s with pre-stressed concrete cylinder pipes, or PCCP, made from a combination of steel and concrete. First used during World War II to help minimize the use of precious steel, this pipeline type is used extensively around the world.

Numerous failures of similar pipes nationwide prompted the Water Authority to take proactive measures to reinforce its PCCP type pipelines with steel liners in an strategic, multi-decade program starting in 1991.

In addition, in 2003 the Water Authority started using an innovative carbon fiber technology to conduct urgent pipeline repairs, helping ensure a safe and reliable water supply to the region.

When the Fallbrook project is finished, the Water Authority will have rehabilitated approximately 47 miles of PCCP — more than half of the total in the Water Authority system.

L.H. Woods working on one of its first projects for the Water Authority in 1960. Photo: Courtesy L.H. Woods

L.H. Woods & Sons Honored for 60 Years of Enhancing Region’s Aqueducts

After 60 years of work upgrading the San Diego regional aqueduct system, Vista-based L.H. Woods & Sons, Inc. was honored by the San Diego County Water Authority’s Board of Directors upon completion of the company’s final project under local ownership for the Water Authority.

The Board formally marked the successful conclusion of the $28.6 million Lake Murray to Sweetwater Reservoir pipeline relining project at its September 27 meeting. L.H. Woods reinforced 4.3 miles of large-diameter pipeline to extend its service life by decades. At the meeting, the Board adopted a resolution honoring Woods for decades of unequaled service to the region’s 3.3 million residents and its $220 billion economy.

L.H. Woods works on the 2nd Aqueduct in 1972. Photo: Courtesy L.H. Woods

L.H. Woods works on the 2nd Aqueduct in 1972. Photo: Courtesy L.H. Woods

Since Woods’ first Water Authority project in 1959 to excavate the Second Aqueduct, three generations of Woods have worked on approximately 40 projects  for the agency. Work includes construction of several pipeline segments in the 1960s, 70s and 80s; construction of the North County Distribution Pipeline in the 1990s; emergency pipeline repairs near the San Diego River in 2008; and several pipeline relining projects in recent decades.

“Nothing is more important to our region’s economy and quality of life than ensuring our pipelines continue to deliver water without interruption – and no company has played a bigger role in that effort than Woods,” said Jim Madaffer, chair of the Water Authority’s Board. “Woods brings to each project an innovative spirit and an unwavering commitment to excellence that benefits every person in our region every single day.”

L.H. Woods played key role in Water Authority relining project

L.H. Woods working on its final project within the Water Authority's relining program in 2017. Photo: Courtesy L.H. Woods

L.H. Woods working on its final project within the Water Authority’s relining program in 2017. Photo: Courtesy L.H. Woods

In September 2017, Woods started construction on the La Mesa to Sweetwater relining project. Crews conducted most of the work underground and used 17 portals to access the 66-inch and 69-inch diameter prestressed concrete cylinder pipe. Woods deployed specialized installation equipment built specifically for the Water Authority’s aqueduct system to install steel pipeline liners.

Much of the construction was in public rights-of-way in La Mesa on Baltimore Drive (south of the Laport Street-El Paso Street intersection), Nebo Drive (to University Avenue), and Spring Street. Work did not close any streets, through it temporarily reduced lanes for traffic. All construction equipment has been removed, and all streets have been restored.

L.H. Woods working on one of many projects within the Water Authority's relining program in 2000. Photo: Courtesy L.H. Woods

L.H. Woods working on one of many projects within the Water Authority’s relining program in 2000. Photo: Courtesy L.H. Woods

As a certified small business, Woods participated in the Water Authority’s Small Contractor Outreach and Opportunities Program, which is designed to maximize participation by small businesses in the agency’s procurements. In June, the company was purchased by J.F. Shea Co., Inc., one of the largest and oldest privately held construction companies in the nation. Shea’s storied history includes work on the Golden Gate Bridge, Hoover Dam and the pipeline connecting the Claude “Bud” Lewis Carlsbad Desalination Plant to the Water Authority’s regional water distribution system.

With the completion of the La Mesa to Sweetwater relining project, the Water Authority has relined 45 of the 82 miles of pre-stressed concrete cylinder pipe in its system.

An L.H. Woods crew works on emergency repairs for the Water Authority in 2008. Photo: Courtesy L.H. Woods

An L.H. Woods crew works on emergency repairs for the Water Authority in 2008. Photo: Courtesy L.H. Woods

Pre-stressed concrete cylinder pipes were commonly installed between the early 1960s and the late 1980s in water distribution systems throughout the world. This combination of concrete and steel initially appeared to provide unparalleled inner pipe strength and be highly resistant to corrosion. However, pre-stressed concrete cylinder pipes have not been as reliable as predicted, and the Water Authority is proactively relining sections of that pipe to extend their service life by at least 75 years.

The Water Authority’s relining program is an important part of its Asset Management Program, which helps avoid pipeline failures by identifying potential risks before they cause problems. To date, the Asset Management Program has saved water ratepayers more than $200 million by prioritizing repairs, avoiding unnecessary work and maximizing the service life of the region’s 310 miles of large-diameter pipelines.

 

 

 

Once the liners are installed, they are welded together, grout is injected to fill the space between the liners and the original pipe, and cement mortar is applied on the inside of the steel liner. Photo: SDCWA

Innovative Relining Program Reduces Cost, Extends Pipeline Service Life

When the San Diego County Water Authority installed major sections of 66- to 96-inch diameter pipelines in the 1960s, 70s and early 80s, the regional water wholesale agency used cost-saving pipeline material – a combination of steel wires, thin steel pipe, and concrete widely known as Pre-Stressed Concrete Cylinder Pipe (PCCP). Decades later, agencies around the globe realized that some pre-stressed concrete cylinder pipe didn’t last as long as advertised and could fail catastrophically.

The Water Authority deployed a multi-faceted response, using high-tech asset management tools to identify pipeline sections with the greatest risk of failure and a targeted pipeline relining strategy that minimizes community impacts during construction. The agency’s relining program started in the 1980s and ramped up in the early 2000s.  Today, it is on track to complete more than 45 miles of relined pipeline in the next few months.

The current project is taking place deep below the urban streets of La Mesa, California, where the Water Authority and its contractor, L.H. Woods & Sons, Inc., are on schedule to conclude by summer. The delicate, 4.3-mile operation started in September 2017 after years of cross-departmental preparation to ensure the work on the $28.6 million contract could be completed in a cost-efficient fashion without impacting water deliveries. Instead of trenching and removing the old pipe, crews excavate 13 entry portals at strategic points, then insert steel liners into the pipeline using a specially designed cart. When the pipe installation work is done, the portals are backfilled, the streets are repaved, and the pipeline is put back in service for at least another 75 years – at about half the cost of a conventional pipeline replacement project.

Looking for weak spots in system

To identify sections of its 310-mile large-diameter pipeline system that require relining, the Water Authority relies on a suite of high-tech monitoring tools that are part of its pioneering asset management strategy.

Weak spots are often first detected with a “PING!” indicating a snapped steel wire in the PCCP. That sound is relayed through acoustic fiber optic cables – installed as an early warning system inside pipelines – so that Water Authority staff can be alerted by email and cell phone. Each ping is matched with results from Remote Field Eddy Current assessments and visual inspection data, then mapped using Google Earth.

With that information, pipeline segments are plotted on a risk matrix showing the condition and impact of failure. The sections with high risk and high consequence of failure are prioritized for upgrades. On occasion, emergency repairs are required where failure is imminent and the risks are significant. Other, less risky sections continue to be monitored and managed to maximize their service life. This risk-based approach has allowed the Water Authority to avoid more than $200 million in infrastructure spending.

Planning for success requires coordination

Planning for the current project started in 2011. The long lead time was necessary, in part, to coordinate with two of the Water Authority’s retail member agencies that would not be able to take water deliveries from the pipeline when it was down for upgrades. Local or stored supplies in surface water reservoirs could be used in case they were needed during the project.

Critical planning elements also included accounting for other utility assets, property lines and easement rights, environmental impacts, traffic flow and construction noise. Coordination with the local power utility, the regional transit agency and local city officials helped align schedules of concurrent projects, timely address unforeseen conditions and establish relationships to endure potential mid-course project revisions.

During the design phase, Water Authority staff also identified environmental resources requiring protection and mitigation measures. For instance, noise impacts need to be addressed during construction with the installation of large wooden sound walls around work sites. In addition, the plan included with silt fences, fiber rolls and street sweeping to protect nearby waterways from storm water runoff. In addition, an environmental monitor routinely assesses the contractor’s compliance with environmental commitments.

Pipeline relining program extends use 75 years

Relining is often an elegant solution to pipeline deterioration, but it’s not a simple one. The Water Authority’s solution is to use multiple portals, or entry points, to access sections of the pipeline at strategic spots. The footprint of each of the 13 portals for the current project is approximately 25 feet by 60 feet. Photo: SDCWA

Relining is often an elegant solution to pipeline deterioration, but it’s not a simple one. The Water Authority’s solution is to use multiple portals, or entry points, to access sections of the pipeline at strategic spots. The footprint of each of the 13 portals for the current project is approximately 25 feet by 60 feet. Photo: SDCWA

Relining is often an elegant solution to pipeline deterioration, but it’s not a simple one. Crews can’t just insert a single 4.3-mile-long steel liner, partly due to curves and changes in elevation along the route. The Water Authority’s solution is to use multiple portals, or entry points, to access sections of the pipeline at strategic spots. The footprint of each of the 13 portals for the current project is approximately 25 feet by 60 feet. When accounting for laydown, staging and other related work areas, the project encompasses 12.5 acres.

Each portal serves as ground zero for construction, including site excavation and removal of two 20-foot sections of existing pipe to make room for work crews operating the specially designed liner carts. The initial project design identified portals located roughly 2,000 feet apart. However, the contractor adapted its liner carts to better navigate curves and elevation changes. This innovative approach meant the project required fewer portals, saving money and significantly reducing impacts to nearby neighborhoods.

Once the liners are installed, they are welded together, grout is injected to fill the space between the liners and the original pipe, and cement mortar is applied on the inside of the steel liner. To complete the work, new 20-foot sections of the pipe are installed – reconnecting the pipeline through each portal. Then, the portal areas are backfilled, and the portals are returned to like-new condition.

While construction crews carry out that work, the asset management team stays on mission by using removed pipe to perform destructive load testing of pipe sections. On the current project, testing showed steel relining can withstand advanced deterioration of the outside pipe – helping to confirm that steel liners can last at least 75 years.

Reducing neighborhood impacts during construction activities

While the number of portals in the current project was reduced, construction activities remained significant for several months in the highly urbanized area. Four portals were in a four-lane road, temporarily reducing traffic to one lane in each direction. Additionally, two portals were adjacent to major retail parking lots, and six others were less than 100 feet from homes.

From design through construction, the Water Authority conducted significant public outreach, including open house events for neighbors to meet agency staff; distribution of postcards and doorhangers to thousands of neighbors; and the development of “Open During Construction” signs for retail centers. This proactive outreach kept stakeholders engaged with project activities, helping to reduce complaints and resolve issues quickly.

When the current relining project wraps up this summer, the Water Authority will have relined more than half of its pre-stressed concrete cylinder pipelines – a critical part of the agency’s commitment to ensure a safe and reliable water supply that sustains a $220 billion regional economy and the quality of life for 3.3 million residents.