Abstract: In order to investigate the influence of various recharge and discharge conditions on the behaviourof the aquifer and also to evaluate present groundwater management practices in Erzin and Dörtyol plains the hydrographs of seven observation wells were studied.The well hydrographs show excellent correlation with the dry and wet periods. In spite of excessive irrigationpumpage since 1974, the groundwater reserves of Erzin plain have not been affected significantly. Starting from 1976,which also corresponds to the beginning of the wet years, the groundwater levels have risen steadily in both plains.During the period 1974 -1978 the groundwater levels in Erzin plain show an average rise of 10 m and in Dörtyol ?lainabout 4 m.The present groundwater management practice seems to be quite adequate for Erzin plains. However, in the longterm, with the present groundwater management policy, the groundwater levels in Dörtyol plain may show a general decline and also produce an undesirable salt water intrusion problems.