Dam construction is one of the methods for storing surface water. Estimating the service life and economic efficiency of dam is one of the most important cases in estimating the design of it. The most important problem that threatens the useful life of the dam is input sediment to reservoir. Life expectancy of a dam reservoir is measured with respect to the incoming sediments. Estimation of suspended sediment in rivers plays an important role in estimating the useful life of dams. Many methods such as statistical methods USBR (United States Bureau of Reclamation) and FAO (Food and Agriculture Organization) and moderate categories method are used to measure suspended. In this research the mentioned statistical and some other methods are used in Mahabad dam. By using sediment volume and the estimated flow rate Sediment loads is measured at different times in this method and its accuracy is estimated by correlation coefficient. The gained results show that the sedimentation estimates by using USBR and FAO with two correlation curves methods are useful and have more correlation coefficient.