• Effluent recharge to the Upper Santa Cruz River floodplain aquifer, Santa Cruz county, Arizona

      Scott, Paul S.; Mac Nish, Robert D.; Maddock, Thomas, III; Department of Hydrology & Water Resources, The University of Arizona; Arizona Research Laboratory for Riparian Studies (Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ), 1997)
      The City of Nogales, Arizona, is in the Santa Cruz Active Management Area and is subject to the assured water supply and conservation mandates of the 1980, Groundwater Management Act (State of Arizona, 1980). The primary water supply for both Nogales Arizona, and Nogales, Sonora, (commonly referred to as Ambos Nogales) is groundwater pumped from the shallow alluvial aquifers which underlie the Upper Santa Cruz River in Arizona and Mexico, and its tributaries (principally Nogales Wash and Potrero Creek). Nogales, Sonora also obtains water from the Los Alisos Basin, which is south of the Santa Cruz Basin in Mexico (Carruth, 1995). The NIWTP provides wastewater treatment for Ambos Nogales, and discharges treated wastewater to the Upper Santa Cruz River near the confluence with Nogales Wash and Sonoita Creek. The discharge of effluent creates an intermittent stream from the NIWTP outfall for approximately 13 river miles to Tubac, Arizona. The conservation mandates of the 1980, Groundwater Management Act (State of Arizona, 1980) require the City of Nogales, Arizona to prove the existence of a 100-year water supply as a condition for future growth. The Act also allows Nogales, Arizona to receive recharge credits for the portion of effluent that recharges the aquifer underlying the Santa Cruz River. The recharge credits will be used by the City of Nogales as partial proof of a 100-year water supply (Carruth, 1995).