Sediment Yield Analysis in Tahtaköprü Dam Basin

Abstract

The determination of the volume of water to be stored is one of the most important criteria for dam and pond planning and operation. This amount is calculated locally prior to planning studies, and a bathymetric map is created following water storage in the reservoir. Because of sedimentation during the operation period, the volume of the reservoir decreases over time, and this situation appears as a problem in the operation of the water structure. In this study, the reservoir storage volume changes and reservoir sediment accumulation rates between the locally produced map before the construction of Tahtaköprü Dam and the hydrographic survey maps prepared during operation period were investigated by using GIS modules. It was determined that the decrease in the storage volume of the dam reservoir at the maximum water level by 9.15% and at the minimum water level by 51.90% was due to sediment accumulation. The effect of the changes in the land cover and forest area in the basin on reservoir sedimentation was examined and it was found that land cover and forest area in the basin have reduced sediment accumulation in the reservoir. Furthermore, sediment thickness change was mapped to compare the decrease in the storage volume capacity of the reservoir at the maximum water level and at the minimum water level by comparing the digital elevation models of 1962, 1980 and 2014 to support the decision-makers on determining reservoir operation rules in order to benefit water resources effectively within the scope of sustainable management of water resources.