Posted on April 16, 2025
The weekend brought a series of beach closures to Coronado as Mexico works to repair a critical segment of its wastewater treatment infrastructure.
The city’s southern beaches – the Silver Strand Shoreline and Coronado Beach at Avenida Lunar – closed April 12, with the northernmost stretch of Coronado Beach closing on April 13. The closures were prompted by elevated bacteria in the water.
Mexico began diverting 3-5 million gallons per day (MGD) of untreated wastewater into the Tijuana River on April 8, according to the US Section of the International Water and Boundary Commission.
The temporary diversion comes as Mexico repairs its International Collector. Specifically, a junction box must be dried so it can be rebuilt with reinforced concrete.
To remove as much wastewater as possible from the river, Mexico activated one pump of its PBCILA lift station on Friday, according to Maria-Elena Giner, commissioner for the IBWC.
The station is usually turned off during the dry season, and the US loaned Mexico a front-end loader to clear sediment around the station’s intake valves, expediting the station’s activation.
However, Giner said, turning one pump on is not likely to address all of the 3-5 MGD of sewage being diverted into the river. That diversion is expected to end April 17, when Phase 1 of Mexico’s International Collector project is complete.
The International Collector is a pipeline that carries raw sewage from Tijuana to treatment plants, and it is aging and prone to leaks. Mexico is relining the existing pipeline and will connect a bypass line in the interim. (Read more about that project here.)
The project is one of many underway in both Mexico and San Diego to address the ongoing Tijuana sewage crisis, in which millions of gallons of untreated wastewater is dumped into the Pacific Ocean each day. An overview of other projects and their timelines is here.
During Phase 2 of Mexico’s International Collector project, the IBWC anticipates that the pipeline will not send wastewater to the South Bay International Wastewater Treatment Plant (SBIWTP) in San Diego for six days.
During that interruption, PBCILA will be turned off again, and another pump will send the wastewater to the Mexican coast, Giner said.
A start date has not yet been decided for Phase 2, though Giner said the IBWC and Veolia North America, which operates the SBIWTP, are planning for the disruption of wastewater flow.
Meanwhile, Coronado’s ocean-facing beaches are closed. Updated beach statuses are available on the San Diego County Beach and Bay Program website.
