NOGALES, AZ – The U.S. Section of the U.S.-Mexico International Boundary and Water Commission (USIBWC) announced that it has completed the rehabilitation of a half-century-old wastewater pipeline known as the International Outfall Interceptor (IOI) in Nogales, Arizona.
The pipeline, installed between 1970 and 1971, conveys wastewater from Nogales and Rio Rico in Arizona, and Nogales, Sonora, along 9.9 miles from the U.S.-Mexico border to the Nogales International Wastewater Treatment Plant (NWTP) in Rio Rico.
Due to funding constraints, the USIBWC divided the project into five phases that prioritized the most deteriorated pipeline segments. The first contract, awarded on July 13, 2021 to SAK Construction (SAK) for phases 1 through 3 for $13.8 million, was completed on August 14, 2023. The second contract was awarded on September 30, 2022 to SAK for phases 4 and 5 for $15.3 million. In April 2024, SAK completed the rehabilitation of the pipeline and manholes.
USIBWC noted that only the restoration of areas disturbed during construction remains to complete the project.
“This project will reduce the risk of wastewater spills that Nogales has historically suffered from the collapse of portions of the IOI,” said Maria-Elena Giner, USIBWC Commissioner.
SAK used CIPP (Cured-in-Place-Pipe) technology, in which a liner was inserted into the existing pipe and then cured to form a solid pipe within the old structure. Because this technology did not require excavation of the pipeline, traffic disturbance was minimized, construction costs were reduced, and project duration was shortened.
The project was undertaken because the pipeline had reached the end of its useful life. Long-standing structural integrity problems caused periodic discharges of raw sewage along the IOI in the communities of Nogales and Rio Rico for years.
