Modification to the hardisty equation, regarding the relationship between sediment transport rate and particle size

Bagnold-type bed-load equations are widely used for the determination of sediment transport rate in marine environments. The accuracy of these equations depends upon the definition of the coefficient k₁ in the equations, which is a function of particle size. Hardisty (1983) has attempted to establish the relationship between A-, and particle size, but there is an error in his analytical result. Our reanalysis of the original flume data results in new formulae for the coefficient. Furthermore, we found that the k₁ values should be derived using ul and u_1cr data; the use of the vertical mean velocity in flumes to replace u₁ will lead to considerably higher k₁ values and overestimation of sediment transport rates.