Study of Sedimentation in the SefidRoud Dam in Depth Evaluation and Comparing the Results with the Methods By Usbr and Fao

One of the fundamental issues with the operation of surface water resources is erosion, and sediment transport. Reducing the reservoir’s useful life and declining the reservoir storage are subsequences of erosion and sediment transport. These natural events occur in different geographical circumstances. Since the major part of the watershed sedimentation consists of suspended sediments, the amount of suspended loads, has a special priority. (Kişi 2007) Determining the amount of erosion or sediment transportation is practically very difficult. So far different methods have been proposed and among are methods for estimating the suspended load of rivers, hydrometer station sediment survey, sediment rating curve approach, depth evaluation and extrapolation are common. In order to determine the density of sediments, rating curve methods are the most popular. The rating curve method uses power relations fitted curve water discharge and sediment discharge. Hydrologists use rating curve methods in the case that there is no real suspended load, or if the sedimentation data is not accurate enough and remarkable differences in results are observed between measurement data and outcome, or when there are no long term measurements. It should be noted that measuring and monitoring the amount of suspended load by using depth evaluation method is costly. In this study, the FAO and USBR approaches are used to estimate the performance of sediment rating curve methods, and the results are compared with the results of the depth evaluation of Sefidroud watershed. The results of this study indicate that USBR method can be introduced as an optimization method in the Sefidroud watershed by using classified statistics.

Rating curve method, FAO, USBR, sedimentation, depth evaluation