In this study, it is aimed to investigate the changes in water storage capacity and the changes in bottom topography by additional data and developments in addition to GIS supported analyzes based on hydrographic measurements of Seyhan Dam Reservoir, and to provide the current results with respect to reservoir management in Seyhan Dam Reservoir by evaluating the current state of sediment accumulation. In this study, GIS technology is used to evaluate spatial and temporal changes of sediment accumulation in the period of hydrographic measurements in Seyhan Dam Reservoir. Sediment observation data of Cakit and Korkun streams, which are the sediment source of Seyhan Reservoir in present, are used to determine the current state of sedimentation in the reservoir. Calculations made by researches with various techniques in previous years and GIS results to examine the change in storage volume in Seyhan Dam Reservoir between measurement years are presented. Since Catalan Dam was taken into operation, the transport of sediment from main line of Seyhan River has been prevented, and technical measures developed in cakit branch are considered to be important in terms of sustainable management. It is determined that the maximum reservoir volume in Seyhan Dam Reservoir is reduced by 0.30% from 2005 to 2017 by evaluating the sediment observation data of E18A028 Cakit Stream-Salbas sediment observation station and E18A020 Korkun Stream-Hacili Bridge sediment observation station. As a result, current results on the effects of sediment accumulation on the reservoir operation in Seyhan Dam Reservoir are obtained.