More putrid-smelling brown water is emptying into Imperial Beach from the Tijuana River - and

South Bay residents fear that it's another sewage spill.

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The city of Imperial Beach reported a massive brown plume in the ocean and a foul smell of sewage, according to a spokeswoman for the International Boundary and Water Commission, a joint U.S.-Mexico agency that oversees the river.

The IBWC spokeswoman told 10News they asked Mexico to investigate the new plume on Thursday afternoon, but as of Thursday night, Mexico has not responded.

Friday, San Diego County issued a water contact closure for all of Imperial Beach due to sewage-contaminated runoff from the Tijuana River. Sample results showed "contamination of ocean water is occurring in Imperial Beach."

The county said flows from the Tijuana River Mouth could be moving north.

South Bay residents are still reeling from the 230-million gallon raw sewage spill in February from a broken sewer line in Tijuana which poured raw sewage into the river for 17 days.

“Why would we be smelling it if it wasn't raw sewage, this far north of the river?” said South Bay resident Baron Partlow.

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No one from Mexico told the U.S. about the spill. It was discovered after Imperial Beach residents complained of the horrible smell.

We are still waiting for the IBWC report on how and why that sewage spill happened.