“…According to the principles of hydraulic flow units, the distribution of the logarithm of the flow zone index in each hydraulic flow unit is the normal distribution. This method applies this principle and determines the number of hydraulic flow units (Al-Rbeawi and Kadhim, 2017;Alhashmi et al, 2016;Bhattacharya et al, 2016;El-Sayed et al, 2021;El Sharawy and Gaafar, 2016;Ismail et al, 2021;Kazemzadeh et al, 2013;Kianoush et al, 2022a;Kianoush et al, 2023a;Mirkamali et al, 2016;Roslin and Esterle, 2016;Salehi et al, 2015;Shakiba et al, 2015).…”