"The transport of sediments, meaning granular material such as silt, sand and gravel, plays an important, if not the most important role in all problems of fluvial hydraulics. This science deals with the interrelationship between flowing water and sediment particles. Sediment transpoti processes have a dominant influence on morphology and stability as well as on water and habitat quality in channels, on coastlines and in estuaries. Therefore, nearly every major project in hydraulic engineering is affected by sediment transport. This phenomenon is very complex, and for that reason a theoretical study can only be carried out in simple or simplified cases. The existing formulae, developed for the quantitative determination of the transport of sediments, are mostly based on limited experimental results, and thus should be used with caution. On the other hand such formulae are of great value but must be applied within the conditions under which they have been derived."--introduction.