Sonoran Institute Calls for Binational Collaboration on International Outfall Interceptor Breach Impacting Santa Cruz River

TUCSON, Ariz. (August 2, 2017) — As the result of a leak discovered last week in the International Outfall Interceptor (IOI) near Nogales, Arizona, raw sewage is spilling into Potrero Creek. Water from Potrero Creek flows into the Santa Cruz River, one of Southern Arizona’s most important and threatened waterways. Arizona Gov. Doug Ducey declared a state of emergency, saying he was allocating state funds to help with repair management as the state’s congressional delegation urged the International Boundary and Water Commission (IBWC) to address the issue.

The contamination poses a public health risk, is a threat to Southern Arizona’s regional economy and drinking water, and could potentially roll back 10 years of progress the Sonoran Institute and partner organizations have made on restoring the environmental health of the Santa Cruz River.

The IOI, a cross-border pipeline, carries municipal and industrial wastewater to the Nogales International Wastewater Treatment Plant (NIWTP) in Nogales, Arizona, where wastewater from both sides of the border is treated. The pipeline has long needed repair, as this is not the first breach. If not properly repaired, this will not be the last breach given the serious drainage problems in Nogales, Sonora, that lead to erosion damage of border infrastructure.

In the short term, the flow of raw sewage into Potrero Creek must be stopped as quickly as possible to minimize any immediate impacts to public health and the health of the river. However, the overall health of the Santa Cruz River, a critical binational resource that serves as the backbone of this region’s economy, supplies water to communities in Mexico and the United States, and provides vital wildlife habitat, depends on a long-term solution. This long-term solution requires binational collaboration.

The Sonoran Institute calls on the IBWC, Comisión Internacional de Límites y Aguas (CILA), and state and local governments in both Arizona and Sonora to immediately engage in binational collaboration to holistically address watershed health. Addressing drainage problems and replacing the aging infrastructure of the IOI is a necessary first step.


Claire Zugmeyer, Sonoran Institute
(520) 290-0828 x 1143,