Mysterious Sewage Spill Baffles Officials

By MacKenzie Elmer, the Voice of San Diego

January 14, 2022

Federal officials are investigating why millions of gallons of sewage-laden water isn’t making its way from Tijuana to the international wastewater treatment plant in the U.S. Instead, that untreated wastewater is flowing into San Diego through a border drain, which indicates there’s probably a broken pipe or a clog somewhere in Tijuana.

The runaway flow began Jan. 7 around 1:30 p.m. when almost a million gallons of sewage escaped from Tijuana through Stewart’s Drain, which sits just east of the International Wastewater Treatment plant operated by the International Boundary Water Commission.

The plant can handle up to 25 million gallons of wastewater per day, and usually does. But around that same time, the plant started receiving just over half the wastewater it normally should from Tijuana — about 12 to 13 million gallons, Lori Kuczmanski, a spokeswoman for the commission, said Thursday. That basically means wastewater is escaping the sewage system somewhere up the pipeline in Tijuana and finding its way into the Tijuana River on the San Diego side elsewhere by gravity.

“It was a little alarming,” Kuczmanski said. “We don’t know right now if there’s a break in the system or a broken pump. We’re exploring everything.”

IBWC recorded another over half-million gallon sewage spill on Jan. 8 beginning around the same time in the afternoon. Similarly, on Jan. 9, the recorded spill was over 13 million gallons of wastewater. On Jan. 10 came another 17 million gallons.

Kuczmanski said the commission believes these spills are happening in the afternoon because that’s when Tijuanans are getting home from work and using sinks and plumbing.

“The frequency and upward trend is very concerning,” wrote Morgan Rogers, a field officer for IBWC, in a Jan. 11 spill report. Rogers wrote he’s working directly with Mexican officials to determine the cause of the spill.

Another over 8 million gallon spill on Jan. 11 started around 2:45 p.m. and ended at 6 a.m. That was apparently due to a backup within the International Collector, a pipeline that carries wastewater to the International Wastewater Treatment Plant, according to an IBWC report. That pipeline is old and needs to be rehabilitated. A 2019 report on the Tijuana River sewage issue by the North American Development bank had about less than three years of useful life.

Chris Helmer, director of environment and natural resources for Imperial Beach, the San Diego city closest to the border, said despite the spills he’s seen an improved response from IBWC to investigate these unexpected sewage spills.

“Before it was local agencies ringing the alarm and calling folks in Mexico, then calling the IBWC who would be non-responsive, following up with the EPA and they’d point us back to IBWC,” Helmer said.

The actual beaches of Imperial Beach, just north of the mouth of the Tijuana River, have been closed since Dec. 8 due to unhealthy coastal water conditions.

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