Application of sediment transport models to a permanent river with non-uniform grain-size distribution

Bed-material load sampled under a wide range of hydraulic conditions in a perennial and poorly sorted sandy gravel-bed river (Arbucies, Catalan Coastal Ranges), is used to test the performance of four well-know bed-material formulae. The degree of agreement between observed and predicted values varies greatly. The best agreement with measured values was obtained using the ACKERS and WHITE (1973) and ENGELUND & HANSEN (1967) models, a reflection of its original design for poorly sorted sediment and streambed formed into dunes. Contrastingly, the wide range of hydraulic conditions from which the data was obtained and the poor sorting of the bed sediment affected the performance of the van Rijn (1984) and Brownlie (1981) equations and, thus, deserves further study.