Page - 478 - in Book of Full Papers - Symposium Hydro Engineering

which has been constructed on Ghermi chai river in the northwest of Iran. Sediment distribution in various reservoir levels is computed and Area-Volume-Height curves for period of 80 years through previously mentioned methods are computed, drawn and compared. 2. DISCUSSION AND CONCLUSION GSTARS3 sediment transport model was used in this study to predict sediment load from the watershed discharged to reservoir. In order to study the problem and calibrate the models, the results are compared with the experimental method of reducing the level. The results of the experimental method of Area Reduction can be reliable, especially at high reservoir levels. The comparison graphs of Volume-Elevation and Area-Elevation before and after simulation (after a 80-year sedimentation period) are shown in Fig.1 to 2. According to the research, the Area Reduction Method to estimate the sedimentation in the reservoir of Garmi Chay dam is a priority. Considering that this method can not predict the exact model of sedimentation in the reservoir of the dam such as longitudinal profile, bottom line of reservoir and sedimentation in different sections of the dam reservoir, this is done using the GSTARS3.0 Model. Comparison of the results of the software in the single-dimensional model and the experimental method of Area Reduction in the low levels of the dam reservoir indicates that the GSTARS 3.0 model is inaccurate near the dam body and transfers a significant amount of sediment input to the outside of the study area. Fig. 1 Volume-Elevation graphs before and after simulation (after a 80-year sedimentation) period Fig. 2 Area-Elevation graphs before and after simulation (after a 80-year sedimentation) period 478