Officials broke ground Friday on a long-awaited project to repair a leaking sewage pipeline connecting Nogales, Sonora and Nogales, Arizona.

The international outfall interceptor carries millions of gallons of sewage daily from both sides of the border to a treatment plant in Rio Rico, Arizona.

But the pipeline, built more than half a century ago, has cracked and ruptured, leading at times to the release of raw sewage.

Dr. Maria-Elena Giner, U.S. Commissioner on the International Boundary and Water Commission, which co-owns the treatment facility with Nogales, Arizona, said the repairs will keep wastewater flowing and protect the surrounding area.

"That will avoid contamination of our environment, reduce the risk of human contact with potential spills," she said.

The treated effluent is discharged from the plant in Rio Rico into the Santa Cruz River.

"One of the things we often don't consider is the sheer value of the water the pipeline brings," said Misael Cabrera, director of the Arizona Department of Environmental Quality. "It starts as wastewater in Nogales, Sonora and then it comes nine miles and gets treated and once it's treated, it's an incredibly valuable resource for Arizona. It sustains two different endangered species and critical habitat along a corridor that's also an economic driver."

Repairs are planned through 2024 using about $38 million in funding, which mostly comes from the federal government as part of a settlement with the state of Arizona.

Crews plan on inserting a liner into the existing pipeline that will be cured to form a solid pipe inside the old one.

Officials say this method will cause less traffic disruption.

But this will leave the existing pipeline in its current route.

"It's definitely a medium-term solution that will be sufficient at least for the next 10 to 20 years," said Giner. "The reality is it will depend on what happens. Does Nogales, Arizona grow as anticipated? Does Nogales, Sonora grow as anticipated?"

The Buzz

Hear more about the long-running problems with the Nogales international outfall interceptor on this 2019 episode of The Buzz.