A Tucson construction company is doing emergency repairs on the International Outfall Interceptor. (Curt Prendergast photo)

NOGALES, Ariz. (AP) A Tucson construction company is being paid $300,000 to do emergency repairs on an international sewage line that carries untreated sewage from Mexico into Arizona.

The flow of untreated wastewater has been pouring into a southern Arizona wash from a partial break in the international sewage line.

The partial breach was detected July 25 in a sparsely populated area north of Rio Rico, Ariz.

Authorities believe the break occurred because of excessive rainwater that put too much pressure on the pipe.

The pipeline, also known as the International Outfall Interceptor, carries wastewater from Nogales, Ariz., and Nogales, Sonora, Mexico, to a treatment plant in Rio Rico.

The wastewater has tested positive for excessive levels of E. coli., Santa Cruz County officials said.

Arizona Gov. Doug Ducey declared a state of emergency and allocated $200,000 to help with repair management.

The city of Nogales, which also declared a state of emergency, said the estimated cost of repairs is $5 million.

The first repairs will include building a cofferdam, which is a watertight enclosure pumped dry to permit construction below the waterline, officials with the U.S. Section of International Boundary and Water Commission said.

An inspection of the sewer pipe will follow to determine what repairs are needed.

The U.S. Army Corps of Engineers will assist with the rebuilding an eroded bank in an unlined portion of the Nogales Wash.

Meanwhile, authorities in nearby Pinal County are warning ranchers and farmers not to use water from the Santa Cruz River for their crops and cattle until the E. coli situation is resolved.

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