Environmental Engineering Reference
In-Depth Information
The total sediment transport can be expressed in ppm by mass as a
function of the unit stream power by:
J
log
VS
−
V
cr
S
w
s
log
c
t
=
I
+
(A.36)
Yangs coefficients are:
0
.
286 log
w
s
d
50
ν
0
.
457 log
u
w
s
I
=
5
.
435
−
−
(A.37)
0
.
409 log
w
s
d
50
ν
0
.
314 log
u
w
s
J
=
1
.
799
−
−
(A.38)
- critical velocity for initiation of motion
V
cr
:
V
cr
=
2
.
05
w
s
(A.39)
The total load transport is calculated by:
q
s
=
0
.
001
c
t
Vh
(A.40)
where:
q
s
=
total load transport (kg/s.m)
c
t
=
total sediment transport expressed in ppm by mass
=
V
mean velocity (m/s)
V
cr
=
velocity for initiation of motion (m/s)
h
=
water depth (m)
S
=
bottom slope
I
,
J
=
coefficients in Yang's function for the total sediment transport
w
s
=
fall velocity (m/s)
d
50
=
median diameter (m)
u
∗
=
shear velocity (m/s)
kinematic viscosity (m
2
/s)
ν
=
Equations A.36 and A.40 have been verified with laboratory and field data
from tests within the following ranges:
- sediment size
=
0.15-1.71 mm
=
- mean velocity
0.23-1.97 m/s
=
- water depth
0.01-15.2 m
- concentration
=
10-585,000 ppm
10
−
3
-27.9
10
−
3
- bottom slope
=
0.043
∗
∗
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