ABSTRACT: Extensive groundwater exploitation over the last two decades has resulted in piezometric level decline and- water quality degradation in the fresh water aquifer in the AfyonPlain., Under these conditions, the prediction of the consequences of the overexploitationrequires the identification of the current head distribution. For this purpose, the spatialand temporal extent of the hydraulic head over the plain is simulated by MODFLOW(Modular -three-dimensional-finite-difference ground-water flow model). The hydraulic` head distribution declines from NW to SE over the plain. The.model shows that there isan increase in the decline of the piezomètric levels after the year 1976 when an intensivegroundwater exploitation is started, and after 1990 when the exploitation is considerablyincreased.. It is .simulated that the-hydraulic head is decreased 5 to 10 m in some parts ofthe plain front the year 1965 to 1998. Under these conditions, groundwater usage In the Plain should he regulated to* establish the natural hydraulic balance and, the terminationof ike uncontrolled gromidwater exploitation