the best methodology is often academic. Specific equations are based upon limited data and
they may not fit the whole spectrum of data from flumes, canals and rivers (Yang and Wan
1991). Therefore, engineering judgment must be used when selecting and applying the
available methods. This Appendix provides additional guidance on the applicability of
selected sediment transport equations based on a comparison of predicted transport rates
with a large data set.
B.2 EVALUATION OF SELECTED SEDIMENT TRANSPORT EQUATIONS
A large compilation of field data was used to test ten widely used sediment transport (bed
material load) equations (Kodoatie 1999, Kodoatie et al. 1999). The data encompass a wide
range of bed materials, from silts to gravels, and a wide range of river sizes, from less than 1
m width to several thousand meters in width.
The ten sediment transport equations that were evaluated are: Einstein (1950), Laursen
(1958), Bagnold (1966), Toffaletti (1969), Shen and Hung (1972), Ackers and White (1973),
Yang (1973) and (1984) for gravel-bed rivers, Brownlie (1981), Karim and Kennedy (1981),
and Karim (1998). Field data include a total of 2,946 sets from 33 alluvial systems.
Additionally, 919 sets of laboratory data from 19 sources were selected to verify the
proposed methods. Tables B.1a and B.1b identify the field data and laboratory data used in
the Kodoatie (1999) study.
B.2.2 Scope of Study
Because no single equation can encompass all alluvial channel conditions, four subdivisions
of river data were analyzed based upon bed material size. These included: gravel-bed,
medium to very coarse sand-bed, very fine to fine sand-bed and silt-bed rivers. Also, the
data were subdivided based upon size of river, i.e.,
Small rivers with widths equal to or less than 10 m (33 ft) and depths equal to or less than
1 m (3.3 ft),
Intermediate rivers with widths greater than 10 m (33 ft) and equal to or less than 50 m
(164 ft) and depths greater than 1 m (3.3 ft) and equal to or less than 3 m (9.8 ft),
Large rivers with widths greater than 50 m (164 ft) and depths of greater than 3 m (9.8 ft).
The range of field and laboratory data are identified in Table B.2. The sediment transport
relations tested are summarized in Table B.3.