The most Appropriate Statistical Method for Suspended Sediment Estimation of Rivers (Case Study: Roodak Station of the Jajrood Basin)

The sediment load that is transported by rivers can create numerous problems such as sedimentation in the reservoir and storage capacity reduction, developed load in the rivers, destruction of structures along the river and transfer of pollution. Therefore, an accurate estimate of the sediment load in rivers is absolutely essential for river engineering, reservoir design, sediment transportation, measuresof environmental damage caused by deposition. Due to the fact sediment load is measured at different times in addition to the lack of reliable observational data in the watershed, empirical equations are used to estimate the sediment load. In this study,to determine the most suitable method for estimating the suspended sediment in Roodak Hydrological Station, we have collected and analyzed data from flow and sediment discharge during the years1972-2008. By the correlation between flow and sediment discharge onthis station of six statistical methods, we chose the best method to estimate suspended load. In a comparison of the accuracy of these methods, we used the statistical indices, RME, MAE and standard deviation. The resultsshowed that the multi-linear (two curves) method wasthe mostaccurate method. Therefore it was selected as the most appropriate method for estimating suspended load in Roodak Station.