Fundamentals of Engineering Design
Table 5.9 Simons and Albertson (1963) Modified Regime Equations
Sand Bed and
Sand Bed and
Cohesive Bed and
Sand Banks
Cohesive Banks
Cohesive Banks
P = C1 Q0.512
3.3
2.51
2.12
R = C2 Q0.361
0.37
0.43
0.51
A = C3 Q0.873
1.22
1.08
1.08
V = C4 (R2 S)1/3
13.9
16.1
16.0
W/D = C5 Q0.151
6.5
4.3
3.0
Simons and Albertson (1963) explain the limitations of the Indian and their own regime equations.
Simons and Albertson (1963) also provide guidance for designing with their equations:
1.
Canals that are formed in coarse non-cohesive material of the type studied by the USBR
(sediment transport < 500 ppm).
2.
Canals that are formed in sandy material with sand beds and banks (sediment transport < 500
ppm).
3.
Canals that are formed in sand beds and slightly cohesive to cohesive banks (good results
when sediment transport < 500 ppm, qualitative results when sediment transport > 500 ppm).
4.
Canals having cohesive beds and banks (sediment transport < 500 ppm).
The USACE (1994) provides guidance on channel design. Their recommendation is to use locally
or regionally developed equations for channel design. However, when this is not possible, Figures 5.34,
5.35, and 5.36 can be used to provide rough estimates for top width, depth, and slope of a channel given
the channel-forming discharge and bed material. Limitations associated with the charts are provided in the
following paragraphs.
USACE Regime Chart Limitations
1.
Where possible, reach-averaged data for existing channels should be plotted and compared
with the indications of the charts, using bankfull discharge as the channel-forming. If bankfull
discharge is not determinable, a 2-year recurrence discharge can be used as the channel
forming. This comparison can indicate how compatible the stream system is with the
assumptions of the charts. The trends of the charts can then be used to estimate changes
appropriate for modifications due to increased in-channel flows.
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