Brown and Caldwell begins rehabilitation work on Allen-McColloch pipeline

Environmental engineering and construction firm Brown and Caldwell announced last month that it was selected by Metropolitan Water District of Southern California (Metropolitan) to provide engineering design services for rehabilitation of the prestressed concrete cylinder pipe (PCCP) portion of the Allen-McColloch Pipeline.

Metropolitan is a regional wholesaler that provides water to 26 member public agencies that, along with their retail providers, serve 19 million people in Los Angeles, Orange, Riverside, San Bernardino, San Diego and Ventura counties.

Metropolitan’s mission is to provide its service area with adequate and reliable supplies of high-quality water to meet present and future needs in an environmentally and economically responsible way. Through its mission, in 2011 Metropolitan authorized the initiation of a $2.5 billion PCCP Rehabilitation and Replacement Program, to develop a comprehensive, long-term effort to manage Metropolitan’s PCCP feeders to maintain reliable water deliveries to its member agencies.

The Allen-McColloch Pipeline (AMP) delivers treated water from the Diemer Water Treatment Plant in Yorba Linda to El Toro Reservoir in south Orange County. The length of the feeder is 26 miles. The southern 9-mile portion consists of PCCP, which varies in diameter from 54 to 78 inches, and is the focus of this effort.

As the design consultant, Brown and Caldwell will perform preliminary design and prepare conceptual drawings for the rehabilitation of the pipeline. The work will include relining the pipeline with a seismically resilient liner; replacing existing valves, flow meters, and structures; and other appurtenant work necessary for rehabilitation.

“We are honored to be chosen for this important project,” said Brown and Caldwell Program Director Dave May. “Our committed team looks forward to collaborating with Metropolitan to minimize community and environmental impacts while maximizing the life of existing infrastructure in the most cost-effective and sustainable manner.”

Brown and Caldwell specializes in large-diameter pipeline rehabilitation, replacement and design. The firm’s resume includes working with the City of Phoenix to investigate, prioritize, and rehabilitate PCCP segments of the 150-mile aging Val Vista Water Transmission main, the city’s most critical pipeline that supplies 220 million gallons of potable water daily to approximately 60 percent of the city’s population.

The Allen-McColloch Pipeline design phase activities are expected to be completed by July 2023. Upon completion, rehabilitation and construction will be sequenced to minimize impacts to member agency service connections.

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