The Tijuana River has been in the news lately as pollution pours into the US from Mexico. To help us understand what’s happening, we spoke with former PPIC Water Policy Center advisory council chair Celeste Cantú, who currently sits on the San Diego Regional Water Quality Control Board.

What are people who live and work along the Tijuana River experiencing?

First, I’m not representing any organization. I’m only speaking for myself and my almost seven decades of living near the border and working on border issues.

The Tijuana River watershed begins in the US, drains into Baja California, turns back into San Diego County, and then empties into the ocean. People ask why Tijuana allows pollution to flow into the US, but hydrology makes it happen—gravity is something we just can’t defy.

First, all wastewater treatment plants shut down at times. When this happens in Tijuana, spills flow downhill into the river, which crosses the US/Mexico border into the US. In some cases, partially treated or untreated sewage flows directly from wastewater treatment plants into the ocean, and ocean currents bring that sewage northwards to San Diego.

These pollutants have a profound impact on residents’ health, tourism, and businesses in Coronado and San Diego. Some beaches have been closed for more than two years; Imperial Beach suffers the greatest impact on a daily basis. The caustic air quality causes noxious smells and lung infections. The smell is worse at night, when large wastewater plants often shut down to do repairs.

Decades ago, the US International Boundary and Water Commission (IBWC) built a plant just north of the border to capture and treat Tijuana River flows. It worked well, but unfortunately the federal government didn’t maintain or expand the plant, and it failed.

The good news is that improvements have been made, and more are planned. The San Diego Regional Water Quality Control Board has recently adopted a plan to increase the plant’s capacity to 35 million gallons a day. It’s not enough—large storm events can bring more than 75 million gallons a day—but it’s better.

What’s causing these higher flows?

We are seeing much larger, flashier rain events. We’ve always had some flashy rain events in this region, but we have a lot more of them now. We’re now seeing a major storm event almost every year.

Tijuana is also one of the fastest-growing municipalities in Mexico, so sewage generation is higher than it used to be. Industrial development has grown a lot with the maquiladoras (factories) in the region. Manufacturing there is discharging heavy metals and other contaminants into the US.

What could fix these issues?

We really need a multilateral approach. We share this watershed; water and trash don’t recognize international boundaries. We need closer coordination and communication with Tijuana, with early warning notification when there’s a problem.

Tijuana is at the end of the drought-prone and dwindling Colorado River system. All of us will need to thrive with less water from the Colorado River. I would love for Tijuana to augment its water supply with indirect or direct potable reuse, with US support to build a plant for that.

It’s to our benefit to invest in the southern part of the watershed—a dollar buys more in Mexico than in the US, and the IBWC is historically underfunded. Well-established organizations such as NADBank can oversee and manage these kinds of investments. And nonprofits on both sides of the border can provide enduring, nature-based, green solutions.

This ongoing crisis is affecting our communities in southern San Diego County. We’ve been piping and treating water to improve water quality and health for hundreds of years in the US. We need a plant on the US side that will capture and treat what flows across the border and dispose of it responsibly.

Final thoughts?

This is an environmental justice issue. The people confronting this live on the border in San Diego County at Imperial Beach and Chula Vista. There’s no escape, except to the hospital. They have been suffering for years on end, and it’s unconscionable. The federal government must do better.

On the California side, support is looking up, with funding from Proposition 4 projects and other sources to hire staff to monitor, permit, and take enforcement actions to regulate the US treatment plant.