of a rip current. The purpose of the tests was to quantify the reliability 

 and reproducibility of results from the streamer trap. Both DUCK85 and 

 SUPERDUCK nozzles were used in the consistency tests. Traps were positioned 

 with one located approximately 1 m offshore and 1 m downflow (seaward trap) of 

 the other (shoreward trap), such that collection of trap-induced transport 

 would be minimal (Figure 40). 



c 



SAND TRAPS 



1m ^ LONGSHHRF CURRENT 



Figure 40. Consistency test arrangement 



117. Kraus (1987) presented two example consistency tests of ten tests 

 conducted during the DUCK85 field data collection program, one showing nearly 

 equal vertical distributions of transport and the other showing greatly 

 differing distributions. Based on the ten consistency tests conducted during 

 DUCK85, Kraus tentatively concluded that the different transport rates 

 measured by closely spaced traps is most likely an accurate representation of 

 the transport rate and that the transport rates actually differed by the 

 margins measured with the traps. 



118. Figures 41 through 50 and Figures 51 through 57 present vertical 

 flux profiles measured with the DUCK85 and SUPERDUCK nozzles, respectively. 

 Agreement between the DUCK85 shoreward and seaward traps is generally good, 

 with the greatest difference occurring at the bottom nozzle. The discrepancy 

 between the two bottom nozzle fluxes may be due to a difference in scour at 

 the bed between the two traps . However , the bottom nozzle flux for the 

 shoreward trap is less than that of the seaward trap for 7 out of 10 cases, 

 indicating that the difference observed at the bottom nozzle may also have 



82 



