Abstract: In this paper application of a finite element model to the unconfined aquifer of the Erzin plain is discussed and the algoritm of the com puter program known as GRWM is described. Thesensitivity analyses include the mesh size, hydraulic conductivity, storage coefficient, boundary conditions, and recharge-discharge rates. Model calibration is achieved for the irrigation season of 1978. Verification of the model is accomplished for the period 1978 thru 1982. The proposed model simulates the behaviour of the aquifer successfully.