River on US-Mexico border carried 167B liter sewage in 2023
The Tijuana River, which straddles the US-Mexico border, carried a record-breaking 44 billion gallons of contaminated water into San Diego County, California in 2023. The US International Boundary and Water Commission (USIBWC) reports that this is the highest volume recorded in the past 25 years. The USIBWC also warns that this year's volumes might surpass all records if the region continues to experience damaging rainstorms.
Unprecedented rainstorms amplify river pollution levels
By June of this year, the USIBWC had already recorded 33.55 billion gallons of polluted water in the Tijuana River. This volume is equivalent to filling 50,800 Olympic-size swimming pools. The pollution consists of stormwater, groundwater, and raw sewage. Recent rainstorms have worsened the situation by bringing significant amounts of this polluted mixture into San Diego County, leading to flooding and extended beach closures.
Cleanup efforts and infrastructure updates
A storm on January 22 resulted in over 1,100 tons of debris filling a north levee near the South Bay International Wastewater Treatment Plant. The USIBWC completed its cleanup in late May. During a recent USIBWC Citizens Forum meeting, officials provided updates on wastewater infrastructure projects on both sides of the border, aimed at reducing untreated wastewater in the river. Commissioner Maria-Elena Giner stated that there are a lot of moving pieces are under monitoring to address the transboundary flows.
Repair and expansion efforts at South Bay wastewater plant
Efforts are underway to repair and expand the South Bay International Wastewater Treatment Plant, which has been noncompliant with its Clean Water Act discharge permit due to lack of proper maintenance. Officials expect the plant to reach compliance by next month, as several parts that have been inoperable for years are being repaired or replaced. The plant's area operations manager, Morgan Rogers, revealed that two of the plant's primary sedimentation tanks are now running after being down since March 2023.
Mexican military rebuilds defunct sewage treatment plant
On the Mexican side of the border, the military is remaking a defunct sewage treatment plant in Baja California that discharges 40 million gallons of wastewater per day into the ocean. Mexican officials expect this plant to be operational by late September or early October. Additionally, Mexico is working on rehabilitating an international collector pipeline which transports wastewater into the South Bay plant, despite its multiple fractures and leaks contributing to polluted flows in the Tijuana River.
