Twelve predictive bedload sediment transport equations are rated against 14 sets of gravel-
bed river field data collected by handheld bedload sampler in Narmab River, northeastern
Iran. To evaluate these formulas two types of grain size namely bedload and bed material
were used. The results show that the equations of Engelund and Hansen, Van Rijn and
Einstein perform well with bed material grain size, while Shocklitsch, Meyer-Peter and
Mueller, and Frijlink yield the best results using the bedload grain size.