Southern California communities affected by the long-running Tijuana River sewage crisis could get some relief from a relatively small infrastructure project, even as larger and more expensive border wastewater upgrades remain years in the making.
San Diego County officials are seeking funding to repair a road crossing at Saturn Boulevard, a site identified by researchers and local leaders as a major source of airborne pollution from the river. The crossing, located along a rural stretch near the Tijuana River, has aging culverts that force sewage-contaminated water through concrete pipes, creating turbulence that can release hydrogen sulfide gas and other pollutants into the air.
The proposed repair is estimated to cost about $25 million. County leaders say the work would not solve the broader sewage crisis, but it could reduce the foul odors and harmful emissions that have affected residents in Imperial Beach, Coronado and other South Bay communities.
San Diego County Supervisor Paloma Aguirre, who has been a leading voice on the issue, said improving the Saturn Boulevard crossing could reduce the churning water that sends contaminated aerosols into nearby neighborhoods.
The project is being pursued while the United States and Mexico work toward roughly $800 million in wastewater improvements on both sides of the border. Those larger efforts are aimed at reducing the untreated sewage that regularly flows through the Tijuana River and into the Pacific Ocean.
For decades, cross-border pollution has closed beaches and threatened public health in southern San Diego County. The problem has worsened as Tijuana’s population has grown and wastewater systems on both sides of the border have struggled or failed, allowing huge volumes of raw sewage to reach the river and ocean.
For years, the focus was largely on contaminated water and the risks to swimmers and surfers. But in 2024, researchers at UC San Diego’s Scripps Institution of Oceanography found that the pollution was also affecting the air. The river was emitting airborne chemicals, including hydrogen sulfide, which can cause respiratory problems and other health concerns.
Residents in nearby communities have reported asthma symptoms, headaches, skin rashes, stomach problems and other ailments, even when they do not enter the water. Families have expressed concerns about children playing outdoors, and some schools have kept students inside during periods of poor air quality.
Researchers traced much of the airborne pollution to the Saturn Boulevard site. The culvert system was originally built decades ago to move floodwater away from nearby farm fields. During flows, water crosses the road and rushes through the pipes, producing foam and spray that can carry contaminants into the air.
County officials say reengineering the site would help control floodwater and reduce the release of toxic gases and particles. But the project still needs a dedicated funding source.
One possible source is Proposition 4, the $10 billion climate bond approved by California voters in 2024. The measure includes about $50 million for border river projects, including work on the Tijuana River in San Diego County and the New River in Imperial County.
The money has been delayed by administrative procedures. This year, state Sen. David Alvarez, a San Diego Democrat, introduced legislation intended to remove some of the bureaucratic hurdles and speed up the release of the bond funds.
Jennifer Toney, a senior engineer with the State Water Resources Control Board, said the agency plans to accept grant applications for the funding from June through August, with awards expected by early next year. Local governments and nonprofit groups working on eligible river projects can apply.
The board could award as much as $20 million for construction projects such as the Saturn Boulevard repair, Toney said. However, the funding is expected to be competitive. Other possible projects include sediment removal, trash capture and additional work along the Tijuana River, as well as proposals for the New River in Imperial County.
A separate request in this year’s state budget seeks $23 million for most of the Saturn Boulevard construction. If approved, that allocation could allow the climate bond money to be used for other border water projects.
Another option is a proposed half-cent sales tax in San Diego County, called the Protect San Diego County Health and Safety Act, which is scheduled to go before voters in November. The tax could raise an estimated $360 million annually, with about $80 million identified for Tijuana River improvements.
The measure would allow up to 22.5% of revenue to be used for environmental mitigation tied to the Tijuana Valley sewage crisis, though it does not specify individual projects such as the Saturn Boulevard site.
While officials work to secure money for the larger repair, San Diego County is also moving ahead with a temporary fix that could be completed sooner. That short-term project is expected to cost about $2.5 million and could be in place by this time next year.
County Public Works Director Marisa Barrie said the temporary work would extend the existing pipes and move water downstream through an enclosed system. The goal is to reduce the turbulence that causes pollutants to become airborne.
Barrie said design work, environmental review and permitting are underway. Construction is expected to take about three months, and county officials hope to finish the project by March 2027, before bird nesting season begins in the area.
Aguirre said the culvert work should be viewed as one piece of a much larger response. It will not stop sewage from entering the river, she said, but it is a practical step that local and state officials can take now to reduce the burden on residents who have endured years of pollution.
Original source: CalMatters
