Waterlogging is one of the main problems besetting agriculture in Pakistan. The paper presents a modification and evaluation of Chieng's model for Rechna Doab area of the Punjab, Pakistan, for existing tile drainage system. The model in its original form considers only rainfall as inflow, whereas the study area inflow comprises rainfall, irrigation supplies and seepage from canal. Thus the need for modification was evident. This modified model analyzed the response of ground water to various recharge and discharge parameters. Daily data of twenty-nine months were used for the identification of the model parameters and for verification of the model applicability by making coincidence between computed and observed water table depth. The results showed a good a reernent between the com arison of com uted and observed water table de ths.
