Seawater intrusion especially in sea front areas may have negative impacts on either water table level and groundwater quality or soil salinity. For example, in some places at South basin of Acisu Creek, groundwater electrical conductivity (ECw) reaches to ECw value of the seawater. In this study, possible seawater intrusion into inland throughout Acisu Creek, variability and existence of trends in ECw, pH and nitrate (NO3) were investigated. For this purpose, two water samplings in June and July 2010 were realized from center line of Acisu Creek throughout 10 km longitudinal-section from creek mouth to spring with an average of each 200 m. Water samples were taken at 50 cm depth in both sampling and at 100, 150 and 200 cm depths after 8.6 km away from the creek mouth in the second sampling only. Average ECw value of 4.70 dS/m was obtained for 10 km longitudinalsection of Acisu Creek. Throughout the Creek, strong decreased trends were obtained for ECw values either in June or July. Electrical conductivity values were less than 3 dS/m after about 6.5 km away from the creek mouth while it was 44.20 dS/m at the point that Acisu Creek flows into Mediterranean Sea. In addition to these, it was found that even at the farthermost point of the study area from the creek mouth, salinities of the water at 200 cm depths from water surface were same as ECw of the seawater. There were weakly increased trends for pH and NO3 values in June but no statistically significant increasing or decreasing behaviors in July. Obtained evidences show that there is high level of seawater intrusion into the inland throughout Acisu Creek
