Comparison of Discharge and Suspended Sediment Load Variations before and after Lar Dam Establishment

The problem of reservoirs dam sedimentation have been serious in the recent years and after other reservoir dam establishment will be more importance. On the other hand, the estimation of suspended sediment load that is main part of sediment input to reservoirs dam major amuse mind of sediment scientists. The precise estimation of sediment rate has been need in the problems such as reservoirs design, sediment transportation, lake pollutant estimation, channels design and digging sediment after floods, estimation of sedimentation hazards to environment and watershed management effects determination. In this research, the daily discharge data of Lar-Poloor station from 1968-1969 to 1999-2000 were used. Whereas Lar dam was constructed in 1980, maximum, mean and minimum discharge and sediment rate was compared for two period, before and after of dam construction. The results of this research showed that totally maximum, mean and minimum sediment in before construction of dam had been more than compare with after dam construction. These results show that the main portion of river sediment trapped in dam reservoir that will be caused dam reservoir utilize age decrease.