applied steady-state ebb flows with a parallel jetty system. A comparison of

Runs 4 and 9 (26-min tide period) in a similar manner shows that the larger sedi-

ment size develops a larger equilibrium area. This difference was possibly related

to the difference in initial conditions, because with Run 4, a wider, shallower

channel existed at the start. Also the different hydraulic characteristics that exist

for the two tidal periods may be a factor.

Substituting the current and area data from Table 2 in Equation 2 produces a

calculated versus measured minimum-inlet-area plot shown in Figure 12. The run

numbers are printed next to the data points, with a "w" next to a run number indi-

cating the equilibrium area after tide plus waves. Despite the differences dis-

cussed in the previous paragraph, all the data points fall in reasonable proximity to

the line of agreement. The average percentage difference between the measured

and predicted areas is 14 percent. The standard error from the predicted value

was 0.016 sq m (0.17 sq ft). The percentage difference for the finer sediment was

12 percent and for the coarser sediment was 18 percent. The correlation coeffi-

cient *r*2 was 0.82.

Figure 12. Comparison of measured and calculated equilibrium areas (to convert

areas to square meters, multiply by 0.0929)

21

Chapter 4 Experiments and Results

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