For the suspended sediment discharge:
Calculate Z for each size fraction using Equation 4.41
Calculate E = 2Ds / yo for each fraction
Determine l1 and l2 for each fraction from Figures 4.9 and 4.10
Calculate PE using Equation 4.32
Compute the suspended discharge from IB qB (1 + PE I1 + I2) from Equation 4.31
Sum up all the qB and all the iB to obtain the total suspended discharge Qss
Thus, the total bed sediment discharge is computed as:
(12) Add the results of Step 5 and 11.
A sample problem showing the calculation of the total bed sediment discharge using
Einstein's procedure is presented in Section 4.13.
4.5.3 Comparison of Meyer-Peter and Mller and Einstein Contact Load Equations
Chien (1954) has shown that the Meyer-Peter and Mller, equation can be modified into the
Figure 4.12 shows the comparison of Equation 4.45 with Einstein's ψ* vs. φ* relation for
uniform bed sediment size and for sediment mixtures using D35 in the Einstein relation and
D50 in the Meyer-Peter and Mller relation. They show good agreement for coarse sands,
but diverge for fine sands. This supports the premise that the Meyer-Peter and Mller
equation is most applicable to coarse grain sizes with little or no suspended load.
Figure 4.12. Comparison of the Meyer-Peter and Mller and Einstein methods for
computing contact load (Chien 1954).