Laursen (Copeland) (Copeland and Thomas, 1989) is a modification to
Laursen's (1958) multiple grain size function, extending its range
to larger gravel sizes.
Laursen (Madden) (Madden, 1993) is a multiple grain size function modified
by Madden for sand bed transport. It has been used for mixtures
of sand and gravel. There is a 1963 modification in HEC-6 that
is not available in SAM.
MPM Meyer-Peter and Muller (1948) is a multiple grain size function for
gravel bed rivers. It is not valid when appreciable suspended
load is present.
MPM, D50 -- Meyer-Peter and Muller (1948), D50 is a version of the multiple
grain size function MPM which has been modified, at WES,
using a single grain size function.
Parker (1990)
is a version of Parker's multiple grain size function. It can be
applied to poorly sorted gravel bed streams. Finer sizes, less
than 2 mm, must be excluded from the specified surface size
distribution and the gradation must be 100% defined, i.e., there
must be a size for which 0% of the material is finer. The bed
material sizes used must be representative of the coarse upper
layer of the bed.
Profitt (Sutherland) (1983) is a multiple grain size function modification of the
Ackers-White formula. It can be used on sand and/or gravel bed
streams.
Schoklitsch (1930) is a version of the Schoklitsch single grain size function
that has been modified at WES for multiple grain size
calculations. It is applicable to sand and gravel bed streams
which do not have considerable amounts of suspended sediment
transport.
Toffaleti (1968) is a multiple grain size function for sand bed rivers. It is not
valid for gravel transport.
Toffaleti-MPM is a combined function for sand and gravel bed streams.
Sediment transport is calculated using both functions by size
class. Calculated bed load from the Toffaleti function is
compared to the total calculated by MPM and the larger is used
for bed load. Suspended load is then calculated using Toffaleti.
Toffaleti-Schoklitsch is a combined function for sand and gravel bed streams.
Sediment transport is calculated using both functions by size
class. Calculated bed load from the Toffaleti function is
compared to the total calculated by Schoklitsch and the larger is
used for bed load. Suspended load is then calculated using
Toffaleti.
49
Chapter 3
Theoretical Basis for SAM.sed Calculations
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