The U.S. Section of the International Boundary and Water Commission (IBWC) operates the Nogales International Wastewater Treatment Plant (NIWTP) and the International Outfall Interceptor (IOI), which provide service to both Nogales, Arizona and Nogales, Sonora. The NIWTP has a total capacity of 17.2 million gallons a day (mgd) and currently treats approximately 15.2 mgd of wastewater—about 3.0 mgd from Nogales, AZ and 12.2 mgd from Nogales, SON.
The IOI was built 50 years ago using reinforced and unreinforced concrete pipe ranging in diameter from 24 to 42 inches. It extends approximately 8.5 miles from the border to the NIWTP located in Rio Rico, AZ, with much of the pipeline installed along the Nogales Wash and Potrero Creek. The IOI has exceeded its useful life and is showing signs of structural deterioration, including corrosion, cracks and wall penetrations. Because of this deterioration, it has been experiencing operational problems, such as groundwater inflow and infiltration and root intrusion, which has resulted in pipeline and manhole failures with untreated discharges to the Nogales Wash.
The project consists of the abandonment of five substandard lateral connections to the IOI, three of which will be relocated to the nearest manhole on the IOI, as well as erosion protection for vulnerable segments of the IOI within the Nogales Wash. The five laterals are:
Bank and erosion protection consisting of grouted rock riprap will be installed at critical areas along the east and west banks of the Wash near Produce Row Bridge, for a total length of approximately 2,000 feet.
The project will help reduce the risk of pipeline failures in the IOI, thereby preventing the potential discharge of up to 15.2 million gallons per day (mgd) of untreated or inadequately treated wastewater to the Nogales Wash, a tributary of the Santa Cruz River. It will also protect vulnerable segments of the IOI and other municipal infrastructure by providing bank and erosion protection in the Nogales Wash consistent with the 100-year flood standard.
|Total Project Cost||US 2.81M|
US 2.81M - NADBank Grant: BEIF