equation. The equation was intended for used in the arid environment of Pima County, Arizona. Due to

the infrequent opportunities to measure sediment transport rates under flood conditions, the equation was

theoretically derived. Meyer-Peter and Mller's equation was used for the bedload portion of the sediment

transport. For the suspended portion, Einstein's method of integrating suspended load was used.

Einstein's suspended load equation is written as:

30h

qs ' q b @ I1ln

% I2

(5.33)

Ds

Figure 5.46

Ratio of Suspended to Total Load Versus Ratio of Shear to Fall Velocities

(from Julien, 1995)

where qb is the sediment transported in the bed layer with a thickness of a = 2Ds. The terms I1 and I2 are

the Einstein integrals. Calculation of the integrals is a cumbersome task that can be performed numerically

or with the use of nomographs prepared by Einstein (1950). The bedload and suspended load were

calculated and combined under a variety of conditions. The range of particle size was 0.5 to 10 mm and

the bed slope ranged from 0.001 to 0.04. The data were then used to calibrate a simplified equation for

total load sediment transport. The equation, as presented in Zeller and Fullerton (1983), is:

n 1.77V 4.32Gr 0.45

qtv ' 0.0064 @

(5.34)

0.30 0.61

d

D50

185

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