The field data were divided into two categories: Group 1 for analysis of the selected

sediment transport relations and proposed equations, and Group 2 for verification and

validation of the proposed methods. The river data sets were divided into two parts in

random order.

A comparison between computed results and field data was conducted and examined.

Statistical approaches were used including the mean discrepancy ratio RD (Bechteler and

Vetter 1989; Wu 1999; Nakato 1990; Yang and Wan 1991; and Hydrau-Tech, Inc. 1998), and

the correlation coefficient CC (Hydrau-Tech, Inc. 1998). The equations for each parameter

follow:

Ri

X

RD =

, Ri = i

(B.1)

N

Yi

(Xi - X)(Yi - Y )

Cc =

(B.2)

(Xi - X) (Yi - Y )

2

2

For perfect fit, the values in Equations B.1 and B.2 are RD = 1 and Cc = 1.

The sediment relations were used to calculate the transport of sediment using data from

Group 1. The sediment load was calculated using mean diameter of riverbed material

(uniform sediment size). The results of comparing computed sediment concentration (Cppm)

and measured sediment concentration measured for four ranges of particle sizes and for

three sizes of rivers are shown in Figure B.1a through d, and Figure B.2a through c.

The applicability of these relationships as reported by Kodoatie et al. (1999) is illustrated in

Table B.4. While certain equations appear to be more applicable to particular bed

characteristics or river size, each equation could, potentially, be applied with reasonable

results for a specific river, if the river characteristics are compatible with those used in the

equation's development. For any specific river, it is recommended that the results be

compared with actual measurements. The following conclusions can be drawn from the

results of this analysis:

Compared to the measured values, none of the selected sediment relations can accurately

predict the sediment discharge. The closest values based upon the discrepancy ratio are

Ackers and White with RD = 0.33 and Brownlie with RD = 4.25. However, based upon the

Pearson correlation coefficient for comparison of computed to measured Cppm, the best

equations are Bagnold and Shen and Hung, both with Cc of 0.70. Considering gravel-bed

rivers, Brownlie's equations, although developed for sand-bed rivers, are the most

acceptable of the ten equations.

B.6

Integrated Publishing, Inc. |