The Arizona Department of Environmental Quality (ADEQ) and local officials confirmed an intermittent sanitary sewer overflow (SSO) in a tunnel under the international border, which transports stormwater from Nogales, Sonora to Nogales, Arizona. A SSO is a release of untreated wastewater and contains raw sewage.
When flowing, the SSO originates from Nogales, Sonora and is exiting the tunnel into the Nogales Wash about one mile north of the international border. Depending on volume of flow and frequency, the SSO could reach the Santa Cruz River.
Work continues on the International Outfall Interceptor (IOI) to fix a partial breach. The breach was discovered last week near the intersection of Old Tucson Road and the Nogales Wash.
Bank stabilization and other preparatory work is proceeding on schedule.
In the meantime, Public Health officials from Santa Cruz County and the State of Arizona advise people to stay out of the Nogales Wash and Santa Cruz River. Even in the absence of untreated wastewater, storm flows are typically high in pollutants that can be harmful.
In cooperation with Santa Cruz County and the Arizona Department of Health Services, Pinal County Officials have issued a warning to those individuals living near the Santa Cruz River to beware of E. coli bacteria that could be in the water. Arizona Department of Environmental Quality have found that samples taken near the partial breach of an untreated sewage line in Nogales, Arizona, contain levels of E. coli bacteria that exceed recommended levels. The partial breach was detected on July 25, 2017 and the flow runs into the Santa Cruz River.
The U.S. Army Corps of Engineers Los Angeles District is seeking approval and funding to provide technical and direct flood fight assistance to Nogales, Arizona, under the Flood Control and Coastal Emergency Act.
The proposed work would fill and armor approximately 280 feet of the exposed International Outfall Interceptor (IOI) in the Nogales Wash between Calle Sonora and Old Tucson Road that eroded from monsoon rains July 23-24.
Santa Cruz County has received the test results from the Arizona Department of Environmental Quality. Initial ADEQ samples found levels of E. coli bacteria that exceeded recommended levels, both below and above the partial breach. Further sampling is being conducted with results still pending.