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Tijuana sewage blasted San Diego beaches at record pace last year. What will this summer bring?

Sewage that overflows the Tijuana border has plagued South Bay coastlines for decades. Ominous yellow and red signs warning of “contaminated water” are often posted in the sand from Imperial Beach to Coronado.

Concerns reached a fever pitch last year after public health officials rolled out a sensitive new DNA-based protocol for testing water quality. a tidal wave of swimming restrictions and warnings followed, stretching through the tourist season.

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As Tijuana’s plumbing continued to crumble, the number of beach closures across the South Bay rose last year to the highest number in more than a decade, according to data from the San Diego County Department of Environmental Health and Quality.

Often cited as one of the country’s top beach destinations, Coronado was plagued by sewage for 51 days, more than double its previous high in 2019.

Heavy rain and repeated mechanical failures in Mexico kept coastlines closed early this year. San Diego leaders are now bracing for what could be another brutal summer.

“I am absolutely appalled by the crisis of sewage contaminating our oceans, poisoning our environment and threatening beachgoers,” said county supervisor Terra Lawson-Remer, whose district includes Coronado.

A beach closure sign warns of sewage contamination in Imperial Beach on Feb. 15.

(Nelvin C. Cepeda/The San Diego Union-Tribune)

Beaches will only be closed if bacteria counts exceed state public safety thresholds and there is a “known sewer leak,” county health officials said. More common in Southern California are the standard yellow-and-white “advice signs” that are placed 72 hours after a heavy rain.

What changed last year was the addition of “warning signs,” which are posted when bacteria counts rise and ocean currents move north from Mexico, but sewage cannot be clearly seen or smelled. The blue and red signs read: “Warning! Beach water can contain sewage and can cause illness.”

The new warning protocolwhich gives beachgoers discretion over whether or not to go in the water was instituted by the county over Fourth of July weekend after city officials complained about repeated closures.

In total, signage was placed along Silver Strand for 133 days and 249 days in Imperial Beach last year to warn people of sewage pollution. In Coronado, 44 ​​of the 51 days the city’s shoreline was lined with sewer signs were during the spring and summer months.

The Tijuana Sloughs, once a coveted surfing spot at the mouth of the river, has not been open since December 2021.

Boom summer

Local officials are shocked by the sheer number of closure and warning days that accompanied sunny skies and clear weather as people flocked from all over the world to places like the Hotel del Coronado.

The iconic establishment, where rooms can cost more than $1,000 a night, declined to comment on this article, other than to say the business “has not been significantly impacted by the closures.”

Still, numerous tourists who visited the area last summer told the Union-Tribune they would think twice about booking another trip to the otherwise posh city.

Youth programs were also negatively affected. The Cal State Games Jr. Lifeguard competition in Coronado was cancelled because of the warning signs, as is the city’s annual Fourth of July Rough Water Swim.

YMCA Camp Surf just north of Imperial Beach was hit particularly hard. Enrollment was reportedly down as parents raised concerns about the lack of access to the ocean. While individual swimmers decide whether to enter the water, many companies are unwilling to risk liability when signs are posted.

This year, YMCA’s popular summer program is hoping for the best but preparing for the worst, said Jamie Cosson, executive director of overnight camps.

“We are now drawing up a plan to take children to beaches further north when we have the closures,” he said. “We have a great facility, a great team. Now we just need to get kids to the ocean.”

The broken wastewater treatment plant

The main culprit behind the summertime pollution is believed to be a defunct wastewater supply along the coast in Mexico at a place called Punta Bandera. Federal officials estimate that the San Antonio de los Buenos treatment plant, about six miles south of the border, spews as much as 35 million gallons of raw sewage per day into the Pacific Ocean.

“This whole conversation wouldn’t be happening if we didn’t have Punta Bandera’s ongoing wastewater,” Imperial Beach Mayor Paloma Aguirre said.

“Coronado is now going to experience what we have unfortunately been experiencing for a long time,” she added. “I feel for both of our communities.”

Waste water ends up in the ocean.

Wastewater from the San Antonio de los Buenos Wastewater Treatment Plant, about six miles south of the border in Mexico, ends up in the ocean.

(The San Diego Union Grandstand)

The closures and warnings are necessary to protect beachgoers from dangerously high levels of bacteria and viruses, provincial public health officials said. Swimmers who ignore the restrictions are at risk of diarrhea, fever, respiratory disease, meningitis and even paralysis.

Water contaminated with sewage carries a much higher risk of dangerous pathogens, such as E. coli, norovirus and salmonella, compared to typical urban runoff that follows rainfall events, officials said.

Not everyone is concerned. Many people surf and swim on South Bay beaches even as closure signs are posted.

Coronado Mayor Richard Bailey has questioned whether his city’s beaches are even more polluted than in recent years or whether the threshold for a bacterial overrun under the new DNA tests has been set unnecessarily low.

“Our biggest concern in Coronado is the simple question, ‘Is the water safe or not?'” he said. “Coronado’s goal is to ensure that the applicable warning and closure policies are directly in line with the actual water quality.”

He has repeatedly pointed out that beaches were closed last year, even when the traditional culture method — in which scientists examine water samples for bacterial growth in a lab — met state health standards for bacteria.

Falk Feddersen, a professor of oceanography at UC San Diego’s Scripps Institution of Oceanography who has worked with the county on identifying sources of sewage from Mexico, agrees the test could use a little more focus.

So far, public health officials have been unwilling to entertain that idea. San Diego is the first coastal county in the nation to institute a federally approved water quality test using the DNA technology. The process was one decade in the makingincluding state and federal approvals and a peer-reviewed study.

However, there is some hope for the future. Significant upgrades to wastewater plants in Mexico are expected to start this year. More than $470 million is slated for such work under a deal signed last year between Mexico and the United States.

That includes repairs to major pipelines, pumps and other facilities in Tijuana. Construction of a new wastewater treatment plant in Punta Bandera is expected by 2025. The US has also agreed to double the capacity of their South Bay International Wastewater Treatment Plant, which serves Mexico, by 2027.

Reports of sewage leakage across the border into the San Diego area date back at least to the 1930s. Significant improvements were made in the 1990s, but Tijuana’s wastewater supplies have not kept up with growth, while many poorer communities are still not connected to the city’s sewage system.

Real-time beach conditions are posted at sdbeachinfo.com.