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A. Bayram et al. / Coastal Engineering 44 (2001) 7999

Fig. 13 shows calculated and measured transport

rate distributions for the run on February 4, 1998,

which is representative for large transport on a barred

profile during a storm. The peak in the transport rate

was observed some distance shoreward of the bar

crest, whereas the formulas predicted the peak to

occur more seaward (i.e., close to the bar crest). In

this respect, the BI, EH, and W formulas yield

locations of the peak transport that are more seaward

than predicted by AW, B, and VR. In contrast to Run

98/02/04, Fig. 14 shows a comparison for Run 98/02/

05 representative of the transport during a moderate

storm. Most of the formulas underpredict the transport

rate, however, the AW and B formulas are yielding

Fig. 14. Comparison between calculated and measured cross-shore

satisfactory agreement. The general features of the

distribution of longshore sediment transport rate for Run 98/02/05

cross-shore distribution are well reproduced by all

from the SANDYDUCK experiment.

formulas, indicating that tuning of the coefficients in

the formulas would considerably improve the predic-

tions.

except B displayed satisfactory agreement with the

Comparisons between the SANDYDUCK meas-

measured rates.

urements and the formulas allowed for an evaluation

of their predictive capability during storm conditions.

Overall, the AW and B formulas predicted higher

transport rates than the other formulas as well as the

5. Discussion of results

measurements. Also, the VR and W formulas yielded

Comparisons between field measurements and cal-

slightly better predictions than the BI and EH for-

culations indicated that several of the formulas yield

mulas. The formulas often failed to accurately predict

predictions that might be considered acceptable in

the location of the peak in the transport rate in the surf

many coastal engineering applications. However, to

zone. However, seaward of this peak, all formulas

objectively quantify the predictive capability of the

formulas, an overall comparison based on individual

point measurements was carried out for each formula.

Fig. 15 summarizes this comparison for the six

selected formulas and all measurements from the three

data sets. In the figure, the circles denote data points

from the DUCK85 and SUPERDUCK experiments,

representative of transport under low-energy condi-

tions, and the squares denote points from the SAN-

DYDUCK experiment, indicative of the transport

during storm conditions. Viewing Fig. 15, the BI

and VR formulas show best agreement regarding the

DUCK85 and SUPERDUCK data, displaying least

scatter around the line of perfect agreement (i.e., the

ratio between predicted and measured transports, qp/

qm, respectively, is one). Most of the computed values

are within a factor 5 of the measured values (see

Fig. 13. Comparison between calculated and measured cross-shore

dashed lines in Fig. 15) for these two formulas. The B

distribution of longshore sediment transport rate for Run 98/02/04

and W formulas have a tendency to overpredict the

from the SANDYDUCK experiment.