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SED2D-WES Version 4.3 Beta
For clay transport, deposition rates of clay beds are calculated with the equations of Krone (1962).
2V
s C1 - τ for C < C
-
D τd
c
S=
(14) and (15)
2Vk 5 3
1 - τ for C > C
- D C τ
c
d
where
τ = bed shear stress,
τd = critical shear stress for deposition,
Cc = critical concentration = 300 mg/l.
Erosion rates are computed by a simplification of Partheniades (1962) results for particle by particle erosion. The
source term is computed by
P τ
S=
- 1
(16)
D τe
where
P = erosion rate constant,
τ e = critical shear stress for particle erosion.
When bed shear stress is high enough to cause mass failure of a bed layer, the erosion source term is
TL ρL
S=
τ > τs
for
(17)
D∆t
where
TL = thickness of the failed layer,
ρ L = density of the failed layer,
∆ t = time interval over which failure occurs,
13
WORKING DRAFT
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