Guardians of the Underground: Coastal Sewer Tunnel Maintenance

Presentation Description: Guardians of the Underground: Coastal Sewer Tunnel Maintenance

Presented by: Daniel Guerra, Collection System Supervisor, South Coast Water District, and Raymond Zarate, Collection System Operator II, South Coast Water District.

South Coast Water District (SCWD) provides water and wastewater collection services to approximately 40,000 people in Dana Point, South Laguna Beach, and portions of San Clemente and San Juan Capistrano. One of the District’s most critical infrastructure assets is its coastal sewer tunnel, which primarily serves the South Laguna Beach and northern Dana Point areas. Originally constructed in the 1950s, the tunnel was recently upgraded and sewer line replaced through the multi-phase Tunnel Stabilization and Sewer Pipeline Replacement Project.

In this presentation, the SCWD Collection System team (Daniel & Raymond) will offer a comprehensive overview of the tunnel project with a special focus on how operations and maintenance were prioritized during design and construction. The Collection System team played a hands-on role during construction, helping ensure the system would be functional, serviceable, and safe to maintain for decades to come.

The session will begin with an introduction to SCWD’s service area and mission, followed by a look at the tunnel’s purpose, history, and the need for stabilization. Attendees will learn about the tunnel’s location along the coastal bluffs, and how it connects to SCWD’s broader wastewater collection system.

Daniel will detail the main tunnel assets, including pipe materials, structures, and access features. He’ll share how his team’s input influenced design/construction improvements that directly support maintenance efficiency. Raymond will highlight the development of a new maintenance schedule, inspection routines, and monitoring methods tailored to the upgraded system.

Additional topics will include entry procedures: covering safety protocols, equipment needs, and authorization processes and cleaning procedures such as hydro jetting and debris removal. Daniel will also touch on emergency response planning and coordination, showcasing how the new program helps ensure reliability under all conditions.

This session demonstrates the value of integrating operator experience into project design/construction, and how doing so can lead to smarter, more maintainable infrastructure from day one.