ABSTRACT
Our ability to predict bedload transport has been
investigated for several decades and this topic con-
tinues to challenge the research community. One
essential problem is that most measurements and
observations were made in flume experiments with
uniform sediments, whereas field sediments are not
uniform. Consequently, bedload transport evaluati-
ons with field data led to the following conclusions:
(i) models are essentially valid under conditions sim-
ilar to those for which they were developed and no
formula is capable of generally predicting bedload
transport in gravel bed rivers ([Gomez and Church,
1989]); (ii) formulas containing a transport threshold
exhibit the poorest performance ([Barry et al., 2004]);
and (iii) equations can underpredict or overpredict
observed bedload transport rates by several orders of
magnitude ([Barry et al., 2004], [Almedeij and Diplas,
2003], [Bathurst, 2007]).
