Environmental Engineering Reference
In-Depth Information
K
4
vB
ν
0
.
37
C
2
g
=
v
2
gDS
=
(4.11)
K
5
Q
0
.
87
A
=
(4.12)
where:
A
=
cross sectional area of the flow (m
2
)
B
=
mean canal width (m)
=
A/h
B
s
=
water surface width (m)
Chézy coefficient (m
1
/
2
/s)
C
=
h
=
mean flow depth (m)
K
i
=
coefficient (i
=
1 to 5) for different canal types
n
=
exponent
P
=
wetted perimeter (m)
flow rate (m
3
/s)
Q
=
R
=
hydraulic mean radius (m)
S
=
bed slope (m/m)
v
=
flow velocity (m/s)
kinematic viscosity (m
2
/s)
ν
=
Table 4.2. Value of coefficients in Simons and Albertson's equations for different canal
types (Simons and Albertson, 1963).
Coefficient
Canal type
K
1
K
2
K
3
K
4
K
5
n
1. Sand bed and banks
6.34
0.4-0.6
9.33
0.33
2.6
0.33
2. Sand bed and cohesive banks
4.71
0.48
10.80
0.53
2.25
0.33
3. Cohesive bed and banks
4.0-4.7
0.41-0.56
-
0.88
2.25
-
4. Coarse non-cohesive material
3.2-3.5
0.25
4.80
-
0.94
0.29
5. Sand bed, cohesive bank and
3.08
0.37
9.70
-
-
0.29
heavy sediment load*
*Sediment (mainly wash load) 2 000 to 3 000 ppm.
Regime theories are available in many areas where irrigation is prac-
ticed, but the fact that these methods are not being transformed to other
places is an indication that not all the physical parameters defining the
problems are correlated by the regime methods (Raudkivi, 1990 and
Bakker et al., 1989).
4.3.2
Tractive force method
The tractive force methods are used for the relationship between the
boundary shear stress and sediment transport. They use the concept of
static stability of a canal in which there is no movement of material (either
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