NOGALES, AZ – The City of Nogales, Arizona, has agreed to transfer its ownership of the International Outfall Interceptor (IOI) to the U.S. Section of the International Boundary and Water Commission (USIBWC).
This agreement, which the City Council approved last April 10, will go into effect once the USIBWC receives $12.5 million for operation and maintenance of the nine-mile pipeline through congressional appropriation or other funding.
“We and other federal, state and local agencies have been working for years to identify the resources and staffing necessary to ensure effective maintenance of the IOI,” said Maria-Elena Giner, USIBWC Commissioner.
Giner noted that in the face of the particular international challenges involved with the IOI, and the $34 million federal investment in its rehabilitation, the USIBWC is eager to assume responsibility for pipeline maintenance.
“Prioritizing preventive maintenance will help prevent breaks and leaks in the pipeline, ensuring more cost-effective repairs and allowing us to better fulfill our mission of treating U.S. and Mexican wastewater,” the commissioner commented.
The transfer of ownership was made possible by the Nogales Wastewater Improvement Act of 2023. The Act was spearheaded by Arizona U.S. Senators Kyrsten Sinema and Mark Kelly and Representatives Raul Grijalva and Juan Ciscomani.
“This agreement underscores the importance of collaboration and investment in our infrastructure. The International Outfall Interceptor plays a crucial role in safeguarding our water resources, and I applaud the City of Nogales, the International Boundary and Water Commission, and all of the partners involved for their dedication to its maintenance and operation,” said Karen Peters, Executive Director of the Arizona Department of Environmental Quality (ADEQ) Cabinet.
“After years of intense negotiations and with the new leadership of Commissioner Maria-Elena Giner, the City of Nogales, Arizona, has agreed to transfer its ownership of the International Outfall Interceptor to the U.S. Section of the International Boundary and Water Commission,” said Nogales Mayor Jorge Maldonado.
The IOI conveys transboundary wastewater flows from Nogales (Sonora, Mexico) and Nogales and Rio Rico (Arizona) to the Nogales International Wastewater Treatment Plant (NIWTP).
Installed between 1970 and 1971, it consists of reinforced and unreinforced concrete pipes ranging from 24 to 42 inches in diameter. Much of the pipe is located under the Nogales Wash and Potrero Creek Canal.
The City of Nogales contracted a study to assess the condition of the pipeline in 2005 and identified significant deterioration of the pipeline.
Rehabilitation of the IOI is being undertaken with financial participation from the USIBWC and matching funds from the Mexican Section of the International Boundary and Water Commission, the State of Arizona, and the Freeport-McMoRan Foundation.
Under two contracts awarded in 2021 and 2022, SAK Construction used Cured-in-Place-Pipe (CIPP) technology, in which a liner is inserted into the existing pipe and then cured to form a solid pipe inside the old pipe. Because this technology does not require excavation of the pipe, construction will disturb less traffic.
The rehabilitation is expected to be completed within the next two weeks.
The approximately 12 million gallons per day of treated water from the NIWTP is an important contribution to the Santa Cruz River watershed, which provides drinking water, for livestock, agriculture and other activities critical to Arizona’s economy. The river also supports critical habitat for migratory species.
