Constructed in the early 1960s, the North Metro Interceptor (NMI) and South Metro Interceptor (SMI) are critical pipelines within the City of San Diego’s wastewater infrastructure. The NMI serves the northern and eastern portions of the city, conveying up to 73 million gallons per day (MGD) of raw sewage, while the SMI supports the South Bay community, handling up to 63 MGD.

Scope of Rehabilitation 

Over decades of service, the NMI and SMI have experienced wear and degradation, with portions lacking redundancy and backup capacity. A 2018 condition assessment revealed the need for extensive rehabilitation to maintain reliability and prevent service disruptions. The rehabilitation project scope includes repairing over 26,000 linear feet of large-diameter sewer pipelines and rehabilitating 66 access structures, including critical diversion structures. Coordinating work across densely populated urban corridors and minimizing disruptions to wastewater service added complexity to the effort.

Working Collaboratively

Kleinfelder’s approach to rehabilitating the North and South Metro Interceptors centers on restoring over 26,000 linear feet of large-diameter sewer pipelines and improving 66 access structures, including critical diversion structures. The strategy includes structural liner repairs for 84-, 96-, 102-, 108-, and 114-inch diameter pipes, targeted spot repairs, and modernization of access points to enhance operational resilience. Kleinfelder worked closely with City staff to align technical solutions with long-term service goals, helping to minimize disruption to wastewater service during construction. The design emphasizes risk mitigation, cost efficiency, and operational flexibility, supporting the City’s broader infrastructure modernization efforts.

Project Results

This rehabilitation is expected to significantly enhance the reliability and capacity of the Metro Interceptors, reducing the risk of system failures and improving flow efficiency. With over $4.4 million allocated for design and support services, the project aims to extend the service life of these vital assets and support the City’s broader wastewater modernization initiatives, including the Pure Water San Diego Program.

Project Details

Location:
San Diego, CA
Owner:
City of San Diego