Western Water News

International Infrastructure Issues Threaten Arizona’s Santa Cruz River

Why fixing a nine-mile sewage pipe is crucial for people and birds.

(UPDATE 6/11/2019) Senator McSally (R) introduced the bipartisan, bicameral Nogales Wastewater Fairness Act, which would assist with the long-term maintenance issues related to the International Outfall Interceptor. In the Senator’s press release, Audubon Arizona Executive Director Sonia Perillo stated: “The Upper Santa Cruz River supports a thriving riverside corridor and is designated an Important Bird Area. The area is recognized for the diversity of birds it supports, thanks mainly to the flowing river sustained by purified wastewater from both Mexico and the United States. We are grateful to Senator McSally for introducing this important legislation, and for the support of Senator Sinema, Representative Grijalva, and Representative Kirkpatrick. Their leadership on this legislation is important for southern Arizona communities, as well as for birds and other wildlife that depend on a healthy and flowing Santa Cruz River.”

(UPDATE 5/28/19) Arizona's 2019-2020 budget included more than $2.5 million dollars for the International Outfall Interceptor Project.

Between southern Arizona in the United States and northern Sonora in Mexico, there is a shared piece of infrastructure failing to do its job. The International Outfall Interceptor (IOI) is a massive pipe that carries wastewater (sewage) from Nogales, Sonora in Mexico and Nogales, Arizona in the United States to a wastewater treatment plant in Rio Rico, Arizona. There, the water is treated, purified, and put back into the Upper Santa Cruz River, which then flows 17 miles in a stretch that would normally run dry without the treated wastewater to sustain it.

The problem is that the nine-mile IOI pipe carrying raw sewage into Arizona for treatment and purification has far exceeded its engineered life and suffers from a backlog of critical maintenance. Pipe breaks are an all-too-regular occurrence, causing raw sewage spills that contaminate the local waterways and threaten the health of the environment and the nearby communities and industries. One event alone during the 2017 monsoon season resulted in the release of approximately 27 million gallons of raw sewage.

Despite these challenges, the purified wastewater is critical for the river, the aquifer, and the habitat the water sustains. The Upper Santa Cruz River is an Important Bird Area. Thanks in large part to the river and its associated riparian habitat, Gray Hawk, Bell’s Vireo, and Yellow-billed Cuckoo thrive in this corridor. The flowing river is also a critical component to groundwater recharge in the Santa Cruz Active Management Area (an area whose groundwater use is regulated by the Arizona Department of Water Resources).

The city and surrounding area of Nogales in Sonora supplies more than 90 percent of the wastewater treated in Arizona. To ensure this water continues to flow into the United States and sustains the flow of the Santa Cruz River, the infrastructure must be fixed. Without repair, we will continue to experience contaminated flows or we may risk losing the flow of wastewater from Mexico altogether.

Thankfully, the Arizona Department of Environmental Quality, among other domestic and international stakeholders, are working to acquire funds to repair the IOI pipe. Repairs are estimated at $48 million in total, with $26 million needed to start the first few phases. Numerous public and private organizations have committed to contributing funds necessary to start the project; however, $2.5 million is still needed. The Arizona Legislature is currently considering House Bill 2448, sponsored by State Senator Frank Pratt, R-8. If enacted, it would appropriate the final $2.5 million to this project and allow the International Boundary and Water Commission—the binational organization tasked with maintenance of the infrastructure—to begin work immediately.

In order to maintain a healthy and flowing Upper Santa Cruz River, this issue must be addressed. It has plagued the nearby communities for far too long, putting public health and our environment at risk.

Additionally, Santa Cruz County’s waterways support a vibrant outdoor recreation economy: Audubon Arizona recently released a report that found outdoor recreation along water in Santa Cruz County, the smallest county in Arizona, generates $142 million dollars in economic output and support 1,600 jobs in the state. Birders, hikers, families, and the local community know that this is a gem in Arizona worth protecting.

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