This project improved the resiliency of the infrastructure, secured the water supply for millions of people, and provided a new approach to designing and upgrading other pipelines throughout the region. (2022 photo courtesy Metropolitan Water District of Southern California).
Project Overview
The Metropolitan Water District of Southern California has earned an Envision Silver award for its Casa Loma Siphon Barrel No. 1 Project to improve the resiliency of a major water supply pipeline vulnerable to earthquakes and damage from subsidence. The project replaces and upgrades a critical component of Metropolitan’s water distribution system, which supplies water to nearly 19 million people in six counties throughout Southern California.
The Casa Loma Siphon Barrel No. 1 pipeline segment — originally built in 1935 and extending 5 miles across the San Jacinto Valley — crosses the Casa Loma Fault and is vulnerable to earthquakes. Leaks have occurred since the 1960s resulting from displacement and settlement due to seismic activity and subsidence from groundwater pumping. Despite previous repair attempts over the years, including pipe replacement, installation of external flexible couplings, and installation of internal seals, a long-term solution had yet to be achieved.
The Casa Loma Siphon Barrel No. 1 Project replaced approximately 1,200 feet of 148-inch diameter steel and concrete pipe segments that cross the fault zone. The new siphon consists of two parallel barrels of 104-inch diameter Earthquake-Resistant Ductile Iron Pipe (ERDIP) designed to withstand up to 13 feet of horizontal displacement during an earthquake and ongoing ground settlement. The pipes were specially designed for Metropolitan and are among the largest earthquake-resistant pipes in the world. The success of the Casa Loma Siphon Barrel No. 1 Project introduces a new design for Metropolitan pipelines that will improve the resiliency of the infrastructure, secure the water supply for millions of people, and provide a new approach to designing and upgrading other pipelines throughout the region.
Quotes
“Metropolitan is honored to receive this recognition for our efforts to ensure Southern California’s water supply is resilient to earthquakes and climate-related risks and reliable for the communities we serve,” said Metropolitan Assistant General Manager John Bednarski.
“This project demonstrates that an innovative and successful project can be implemented in a manner that meets a number of objectives beyond those that may be narrowly related to increasing regional water supply reliability,” said Project Manager Cathy Chau. “And this was a truly creative and ingenious collaboration between Metropolitan staff, the contractor, pipe manufacturer and consultants.”
“The Casa Loma Siphon Barrel No. 1 was a critical project installing an innovatively designed pipeline using ERDIP. This project provides long-term resiliency for vital water infrastructure for millions of Southern Californians. This Envision award was a result of successful collaboration between the engineering, design, construction, environmental, and management teams to create a more sustainable project. A very impressive first Envision Award for the Metropolitan Water District of Southern California!” said Dr. Akima Cornell, PhD, ENV SP, SPEC, GPRO, Sustainability Expert and Principal, Akima Consulting, LLC.
“Congratulations to the Metropolitan Water District of Southern California and the entire project team on the success of this project,” said Kailey Eldredge, ISI Verification Director. “The owner and the project team demonstrated strong leadership in identifying, planning, designing and developing a more resilient and innovative solution for the underground pipeline, one that strengthens the Metropolitan water distribution system on which millions of residents rely.”
This is the first Metropolitan project to pursue Envision Verification. The Envision Silver award is based on an independent peer-review process conducted and overseen by ISI. The verification team evaluated the project’s performance across a set of 64 credits that collectively address sustainability and resilience, including quality of life, stakeholder engagement, project management, community planning, materials, energy, water, land use, ecological impacts, emissions, pollution, climate vulnerability, risk and systems integration. A short summary of the project’s verified achievements follows.
Left: The project’s earthquake-resistant pipe features a joint configuration that allows a pipeline to remain intact, even as individual segments move due to long-term subsidence or a seismic event. Right: pipe placement work in 2022.
Verified Sustainability Achievements
Leadership and Collaboration – The project fostered strong multi-disciplinary collaboration from design through construction. There were workshops early on, for example, that brought together Metropolitan engineering, construction, and operations teams. The collaboration ensured important considerations over the project life were understood and incorporated into the project. As an example, the project discussed how to successfully tie in to the existing water line within a three-week shutdown window, and what backfill to use with the ERDIP to ensure seismic resiliency.
Plan for Sustainable Communities – The project team set and evaluated social goals (minimize impacts on neighbors), economic goals (minimize costs from maintenance and maximize the ability for the pipeline to remain operational), and environmental goals (preventing flooding and water loss from leaks). The project team also ensured the project aligned with the owner’s Urban Water Management Plan and its Seismic Resilience Strategy.
Climate and Resilience – The primary threat to the project is its vulnerability to long-term ground subsidence and seismic activity. A significant portion of Metropolitan infrastructure, including the Colorado River Aqueduct (CRA) and several treated water pipelines, are located near or across active faults. The project developed resilience goals and strategies that were based on the findings from several detailed technical analyses. The resiliency achievements on this project improve the entire Metropolitan water distribution system by incorporating a survey monitoring plan to detect any movement or settlement in the pipeline.
Minimizing Construction Impacts – The project team developed a construction sequencing plan to ensure there were no impacts to water service. The project only scheduled work on the existing line to occur during the annual three-week shutdown of the pipeline — a critical component of the plan, given that the system supplies water to millions of residents throughout Southern California counties as well as the commercial and agricultural sectors. In addition, the project team had a site-specific safety plan that outlined mitigation strategies the contractor was undertaking to minimize construction impacts.
Innovation Credit – To mitigate long-term ground subsidence and seismic risks at the Casa Loma Siphon Barrel No. 1, Metropolitan decided to install an Earthquake-Resistant Ductile Iron Pipe (ERDIP). This type of pipe features a joint configuration that can absorb relatively large displacements. ERDIP joints allow a pipeline to remain intact, even as individual segments move due to long-term subsidence or a seismic event. ERDIP is a unique and proprietary technology developed by the Kubota Corporation. In 2019, there were no other ductile iron pipe manufacturers that offer a comparable product for large pipes that have a similar capability for flexibility and displacement at the pipe joint. The project study recommended replacing the existing 148-inch diameter pipeline with two 104-inch diameter pipelines at the Casa Loma Fault Crossing. Before selecting ERDIP, Metropolitan required a performance test of the 104‐inch diameter pipeline joints to confirm performance. These are among the largest diameter ERDIP pipelines ever designed and manufactured. The Casa Loma project was the first to install ERDIP of this magnitude outside of Japan.
PROJECT DETAILS AT-A-GLANCE
Title: Replacement of Casa Loma Siphon Barrel No. 1
Location: San Jacinto, California
Envision Rating: Silver
Envision Award Date: June 24, 2025
Envision Version: v3
Project Owner: The Metropolitan Water District of Southern California
Lead Envision Firm: Akima Consulting
Design & Engineering Firm: Carollo Engineers, Inc.
Pipeline Manufacturing: Kubota Corporation
Contractor: J.F. Shea Construction, Inc.
Construction Cost of Project: $27.6 M
Project Delivery Method: Design-Bid-Build
Project Status: Completed
Pipe sections are lowered into a trench in 2022.
