“…Groundwater pollution caused by non‐point source contaminants from return flow, such as salts and nitrate, is a major concern in irrigated agricultural basins (e.g., Ayub et al., 2016; Fogg & LaBolle, 2006; Fogg et al., 1999; Han et al., 2016; Harter et al., 1998, 2002; He & Croley, 2008; Laitos & Ruckriegle, 2013; Pauloo, Fogg, et al., 2020; Scanlon et al., 2010; Weissmann et al., 2002; Xu, 2014). Contaminants leach through the root zone to the water table at greater concentration than in the irrigation water, as a large portion of pumped groundwater is evapo‐concentrated due to crop evapotranspiration.…”