They are looking for funds for a solution that would reduce the effects of the Tijuana River pollution

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Communities suffering from one of California’s worst pollution problems could see immediate relief if San Diego leaders can get a key project on the Tijuana River off the ground.

While millions of gallons of raw sewage regularly reach the river, a freeway junction known as the Saturn Boulevard hotspot is the source of most of the air pollution coming from the river.

While the US and Mexico are investing a total of $800 million in modernization of waste water treatment facilities On both sides of the border, local authorities are working on a smaller solution to the hot spot that could improve conditions as early as next year, officials said.

San Diego leaders are trying to find about $25 million to repair the freeway interchange at Saturn Boulevard, where contaminated wastewater flows through aging sewers that are spewing hydrogen sulfide gas and other toxins into South San Diego.

“Fixing the hot spot problem could moderate the turbulence in that area, which in turn would reduce the emissions that basically throw aerosols into the air,” said San Diego County Supervisor Paloma Aguirre, who led efforts to clean up the river.

But they are still trying to find a source of funding for the project.

Sewage pollution from the transboundary river has plagued Imperial Beach, Coronado and other areas of south San Diego for decades. The threat has become more acute as Tijuana’s population has grown and treatment plants on both sides of the border have failed, dumping hundreds of millions of gallons of untreated sewage into the ocean in recent years.

San Diegans have long known that raw sewage in the ocean poses a danger to swimmers and surfers, and local beaches have been closed for years. In 2024, researchers at the Scripps Institution of Oceanography at the University of California, San Diego discovered that pollution not only pollutes the water, but also pollutes the air.

The river emits chemicals into the air, including hydrogen sulfide, which cause respiratory problems and other illnesses among residents of neighboring communities.

Residents suffer from asthma, stomach problems, rashes and headaches even without entering the water. Parents are worried about letting their children play outdoors because they fear it will harm their health. Local schools implement special schedules for rainy days, forcing students to stay inside when air quality deteriorates.

The researchers traced the air pollution to the Saturn Boulevard hot spot. This is a sewer located along a country road near the Tijuana River. The structure, which includes several large concrete pipes, was built decades ago to divert flooding from neighboring agricultural fields. When it rains, water drips onto the road and runs down the pipes, creating piles of foam and dispersing pollutants into the air.

San Diego County officials are trying to find funding to fix the problem. They estimate it will cost about $25 million to redesign the site to control flood flow and prevent toxic gases and particulates from being released into the air.

There are several parallel ways to finance the project, but none of them are certain.

One is a budget line from Proposition 4, the $10 billion climate bond measure that California voters approved in 2024. It includes about $50 million for border projects along the Tijuana River in San Diego and the Nova River in Imperial County.

Although it was approved two years ago, the funds have not been released due to administrative procedures that have delayed their release. this year, State Senator David Alvarez D-San Diego, introduced a bill to streamline red tape and speed up funding through a bond issue.

With funding already in place, the State Water Resources Board will accept grant applications this summer, between June and August, and evaluate and award them early next year, said Jennifer Toney, senior engineer for the State Water Resources Control Board. Local authorities and non-profit organizations working on these rivers can apply.

According to Conti, the board could award up to $20 million for construction projects like Saturn Boulevard. However, Tony noted that this project faces competition from other initiatives on the Tijuana River, such as sediment removal and trash collection, among others, as well as proposed projects on the Nuevo River.

Separately, state lawmakers filed a request in this year’s state budget for $23 million to cover most of the Saturn Boulevard construction. If approved, it could free up bond funds for other border river projects.

A third possible source of funding is a half-cent county sales tax proposed under the title of the San Diego County Health and Safety Protection Act, which will be voted on in November. It could generate $360 million a year, of which about $80 million will go toward improvements to the Tijuana River.

The measure calls for up to 22.5 percent of tax revenue to be allocated to environmental mitigation to address the “toxic wastewater crisis in the Tijuana Valley.” However, it does not specify specific projects such as Saturno Boulevard, as reported by KPBS.

Meanwhile, an even faster temporary solution, costing about $2.5 million, could be ready by this time next year. This temporary solution will widen existing pipes and divert flowing water downstream through a closed system, county Public Works Director Marissa Barry said in an email to CalMatters. This will reduce the turbulence that causes aerosolization of pollutants.

“The team evaluated infrastructure mitigation options at the Saturn Boulevard hotspot and agreed to move forward with a short-term solution that would provide immediate tangible benefits,” Barry said.

Design, environmental analysis and permitting for the project are already underway, according to Barry. Construction is expected to take about three months, and county officials hope to complete it by March 2027, ahead of the area’s bird nesting season.

Aguirre warned that the sewer reconstruction would not clean up the river but would reduce its impact on neighboring communities. “This is not the final solution to the entire crisis. This is something that is within our power to address by working with the state, city and county of San Diego, and which, based on empirical evidence, we know will provide some relief to residents in the affected areas.”