Sediment Transport Relationships for Sand and Silt Loam Soils

ABSTRACT Sediment transport relationship is one of the most important components in soil erosion prediction models. A laboratory study was conducted using three size classes of uniform sand, a sandy soil, and a silt loam soil to investigate the transport and deposition of laboratory study were used to test various sediment transport relationships. Most of the reliable bed load equations tested, which consider critical shear stress, fit the tested, which consider critical shear stress, fit the uniform sand and sandy soil data reasonably well. This result implies that rolling, sliding, and hopping were the major modes of motion for the sandy soil particles under shallow flow conditions. For the silt loam soil, a power function of dimensionless shear stress with an exponent of about 1.5, gave good prediction of sediment transport capacity. For both the silt loam and sandy soils, the presence of low intensity rainfall, which ranged from 0 to 50 mm/h, on the depositional area, did not significantly change the dimensionless sediment transport relationship. A simplified deposition model, using the dimensionless sediment transport relationship developed in this study, simulated the evolution of bed profile for the sandy soil reasonably well.