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Major Rehabilitation of First Aqueduct Complete

The San Diego County Water Authority recently completed a major rehabilitation project on the historic First Aqueduct in North San Diego County. The project renovated and replaced dozens of structures on two large-diameter pipelines, including the historic Pipeline 1. Pipeline 1 delivered the first imported water to the San Diego region in 1947 and remains a vital part of the regional water delivery system. The construction contract for the project was worth approximately $30 million.

San Diego County Water Authority Completes First Aqueduct Project In North County

The San Diego County Water Authority has completed a major rehabilitation project on the historic First Aqueduct in North San Diego County, it was announced Thursday.

The project renovated and replaced dozens of structures on two large-diameter pipelines which delivered the first imported water to the San Diego region in 1947 and remains a part of the regional water delivery system. The construction contract for the project was worth approximately $30 million.

“The First Aqueduct delivered imported water to our region for the first time more than 70 years ago, and it remains critical to water supply reliability for our region to this day,” said Gary Croucher, chair of the authority’s board of directors. “Coordination across water authority departments and collaboration with our member agencies allowed us to complete this extraordinarily complex project and ensure these pipelines operate for generations to come.”

Crews work on First Aqueduct Rehabilitation.

Major Rehabilitation of First Aqueduct Complete

The San Diego County Water Authority recently completed a major rehabilitation project on the historic First Aqueduct in North San Diego County. The project renovated and replaced dozens of structures on two large-diameter pipelines, including the historic Pipeline 1. Pipeline 1 delivered the first imported water to the San Diego region in 1947 and remains a vital part of the regional water delivery system. The construction contract for the project was worth approximately $30 million.

Coordination with member agencies key to success

Over the past two years, four coordinated shutdowns in collaboration with member agencies and communities in North San Diego County ensured minimum impact to nearby neighborhoods and water users.

“The First Aqueduct delivered imported water to our region for the first time more than 70 years ago, and it remains critical to water supply reliability for our region to this day,” said Gary Croucher, chair of the Water Authority Board of Directors. “Through coordination throughout the Water Authority and collaboration with our member agencies, we completed this extraordinarily complex project to ensure these pipelines operate for generations to come.”

The project was completed on January 12 and will be presented to the Water Authority’s Board of Directors at their March meeting.

Proactive asset management program maintains reliable water supplies

The timely rehabilitation of the First Aqueduct is part of the Water Authority’s proactive asset management program. A key element of providing safe and reliable water supplies is continually assessing the agency’s 310 miles of large-diameter pipeline and making the upgrades necessary to continue serving the region. That work is funded through water bills paid by residents and businesses across the county to sustain the region’s $245 billion economy and quality of life.

The First Aqueduct project began in early 2019 and was one of the most complicated pipeline retrofits in the Water Authority’s history. The upgrades included replacing 14,500 linear feet of lining on the steel pipe sections of Pipeline 1, removing 16 associated structures and retrofitting 46 structures. All this work was accomplished while ensuring regional water service remained safe and reliable. In addition, redundant connections to six flow control facilities were added between the two pipelines to improve the aqueduct’s operational flexibility.

Collaboration between departments increased efficiency

The Water Authority’s Engineering Department provided construction management and inspection for the retrofit. Before the pipeline was returned to service, secondary tie-in connections to flow control facilities were added and crews removed bulkheads that were used to isolate pipeline sections during the rehabilitation work. Once the work was completed, staff inspected all work areas in the pipeline to ensure they were clear of construction debris.

After the bulkheads were removed, the Operations and Maintenance team disinfected the highly impacted work areas and then refilled the aqueduct to prepare for a second disinfection of both pipelines with chlorine. Water samples at locations throughout the aqueduct were collected and analyzed to ensure the system was safe to return to service. Once all the samples passed analysis, all flow control facilities were placed back in service and the aqueduct was returned to normal operations.

Technology-Asset Management-Pipelines

Pipelines Assessed in Record Time with Latest Technology

The San Diego County Water Authority’s asset management team recently celebrated the completion of a comprehensive condition assessment of more than 27 miles of the agency’s oldest pipelines. The assessment was performed in record time over just 16 months.

The work was part of a package of rehabilitative efforts on a portion of the First Aqueduct, which includes Pipelines 1 and 2 in North San Diego County. Built in 1947 and 1952, the two pipelines deliver treated water to the region and were constructed using various materials, including reinforced concrete and steel.

Proactive asset management team makes critical repairs

As the pipelines were inspected, areas that required immediate attention were identified and repaired, thereby minimizing future disruptions to water service and impacts to the surrounding environment. Sections of the pipelines requiring future repairs were added to a list of upcoming projects prioritized by the risks and associated costs.

“The asset management team took advantage of scheduled pipeline shutdowns, and with careful coordination, assessment work was performed concurrently with other major rehabilitation efforts in the region,” said Martin Coghill, operations and maintenance manager at the Water Authority. “This innovative approach saved time and avoided unnecessary disruptions in service to our member agencies.”

Throughout the condition assessment process, Water Authority staff worked closely with staff from member agencies to coordinate work being performed in their service areas and any potential impacts. Proactive repairs are crucial to ensuring the reliability of the regional water supply.

Collaboration with multiple contractors to perform complex work

In 2016, a search was conducted to find the best technologies to perform critical assessments to maintain the reliability of the pipelines. It resulted in a multi-technology, multi-contract approach.

The Water Authority partnered with multiple contractors to perform the complex work:

  • Diakont, based in Carlsbad, Calif., used its robotically-mounted technologies to inspect steel pipe sections. High-resolution LASER Profilometry and Electromagnetic Acoustic Transfer technology located internal and external corrosion defects that were then repaired by welding steel patches on the inside of the pipe. This method avoided costly excavations and environmental impacts.
  • Pipeline Inspection and Condition Analysis Corp., based in Edmonton, Alberta, brought its sophisticated Remote Field Technology to San Diego County to scan most of the reinforced concrete pipe using an innovative tool that moved through the pipe at a controlled speed. The technology had been previously used by the Water Authority and consistently demonstrated a high level of accuracy.
PICA, remote field technology, pipeline inspection

PICA uses cutting-edge Remote Field Technology to scan pipelines at a controlled speed with high accuracy. Photo: San Diego County Water Authority

  • Pure Technologies, a Xylem company with an office in San Diego, deployed its Near Field and Remote Field electromagnetic inspection tools to assess portions of the reinforced concrete pipe. With a focus on lightweight components, both tools were successfully conveyed through the pipelines using personnel with rope and pulley support.
technology, pipeline inspection, Pure Technologies

Pure Technologies’ innovative tool uses electromagnetic technology to assess reinforced concrete pipelines using personnel with rope and pulley support. Photo: San Diego County Water Authority

The focus on the Water Authority’s First Aqueduct is the latest chapter in the agency’s long-running strategy to assess critical pipelines and ensure the maximum lifespan is achieved with the most cost-effective methods. Proactive asset management efforts first began in the 1990s and were consolidated into the Asset Management Program in 2009. To date, more than 150 miles of the Water Authority’s total 310 miles of large-diameter pipelines have been assessed using cutting-edge technologies.

The asset management team collaborates with local, national and international organizations in the asset management and water infrastructure fields, focusing on knowledge sharing and asset life optimization.