Irrigating with saline water can significantly increase soil salinity due to crop uptake of fresh water while leaving most salts in soil solution, increasing the soil's osmotic potential. Higher osmotic potential in turn decreases the movement of water toward crop roots (Ayers & Westcot, 1985), requiring crops to expend more energy to extract useable water instead of maturing, and thus decreasing crop yields and profits (Allen, 2000). Salts accumulate in soils or in shallow groundwater in arid and semi-arid areas with every cycle of pumping-and-recharge over the irrigation season (Medellín-Azuara et al., 2008;Schoups et al., 2005). Higher evapotranspiration rates and lower precipitation leave salts in the soil, requiring more surface water (also containing salts) to leach soil salinity to groundwater or drainage systems.When most basin groundwater discharge is pumping for overlying irrigation, with little drainage of salt from the basin, salts imported with surface water and leaching in the basin increase groundwater salinity (Pauloo et al., 2021). This transforms conjunctive use of surface water and groundwater for irrigated agriculture as groundwater becomes saline enough to reduce crop yields. Such groundwater salination is common in the southern and western parts of California's San Joaquin Valley. Nearly two million tons of salt accumulate annually in the San Joaquin Valley, where 250,000 acres of irrigated land have been fallowed and 1.5 million acres are potentially salt-impaired (CV-SALTS, 2017), and lost economic value from salinity could reach $1.2-$2.2 billion/ year by 2030 (Howitt et al., 2009). Globally, many irrigated, semi-arid, and arid agricultural regions have similar conditions (Singh, 2014).Conjunctive use allows some use of more saline groundwater for irrigation (Coe, 1990;Rhoades, 1984). Mandare et al. (2008) studied conjunctive water operations for wheat in a saline groundwater area with scarce surface water supply. Malash et al. (2008) evaluated the effect of saline irrigation on tomato yields and reported that efficient use of low-quality water can leave groundwater salinity unaffected. Other conjunctive water use studies of mixed water qualities of waters for crops such as wheat, maize, and cowpea crops were conducted by