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Press Release
Water Quality

The International Boundary and Water Commission, United States and Mexico (IBWC) conducted a groundbreaking ceremony on January 28, 2022 to rehabilitate a sewage pipeline in Santa Cruz County, Arizona known as the international Trunkline and International Outfall Interceptor (IOI). The pipeline conveys wastewater from the cities of Nogales and Rio Rico, Arizona and Nogales, Sonora to the Nogales International Wastewater Treatment Plant (NIWTP) in Rio Rico.

“This project benefits residents of Arizona and Sonora with state-of-the art implementation technology and will ensure the IOI’s performance for another 50+ years, reducing the risk of wastewater discharges in our community,” said Dr. Maria-Elena Giner, U.S. Commissioner.

Mexican Commissioner Adriana Resendez said, “This work to rehabilitate infrastructure that for many years has served to convey wastewater from Nogales, Sonora is very important in order to prevent wastewater spills that negatively impact the health of residents in both Nogales.”

"This rehabilitation project will ensure continued safe reuse of this valuable water resource that supports critical habitat for two endangered species, aquifer recharge, recreation, and tourism," said Arizona Department of Environmental Quality Director Misael Cabrera, P.E.

The work is being performed by SAK Construction under a $13.8 million contract with the U.S. Section of the IBWC (USIBWC). SAK will use Cured-in-Place-Pipe (CIPP) technology where a liner is inserted in the existing pipeline then cured to form a solid pipeline inside the old pipeline. Because this technology doesn’t require excavation of the pipeline, construction will cause less traffic disruption.

Rehabilitation of the half-century old Trunkline and IOI is being undertaken with funding participation from the USIBWC, and supplemental funds from the Mexican Section of the IBWC, the State of Arizona, and Freeport McMoRan Foundation.

The rehabilitation of the 9.9-mile-long (16 km) pipeline was divided into five phases. The work under this contract is limited to Phases 1, 2, and 3 and includes rehabilitation of 56 manholes and over 5 miles (8 km) of the sewage pipeline. Construction is expected to be completed in 2023. Phase 1 nearest the NIWTP covers 1.6 miles (2.6 km) of the most deteriorated part of the pipeline. Phase 2 covers the first 2.1 miles (3.4 km) from the international boundary, and Phase 3 starts at the terminus of Phase 2 and extends another 1.6 miles (2.6 km) north to near West Produce Row.

The USIBWC expects to award a construction contract for the final two phases of the IOI rehabilitation in 2022 subject to the availability of appropriations.

The International Boundary and Water Commission, United States and Mexico, is responsible for applying the boundary and water treaties between the two countries. The USIBWC operates and maintains the Nogales International Wastewater Treatment Plant.


Lori Kuczmanski
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ADEQ Public Information Officer
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