where a and b are empirically determined coefficients with dimensions 

 consistent with variables in the equation. The coefficients and resulting 

 squared correlation coefficient for each data set are presented in Table 12. 



122. As presented in Table 12, the vertical distribution of sand flux 

 has the highest squared correlation coefficient for either an exponential or 

 power -law relationship. Out of the 20 DUCK85 vertical distributions examined, 

 11 are best described with an exponential fit, and 9 are best described with a 

 power-law fit. Of the 14 SUPERDUCK vertical distributions of sand flux, 10 

 have the highest squared correlation coefficient with a power-law fit, 3 best 

 fit an exponential relationship, and 1 is best described linearly. The 

 majority (14 out of 17) of the shoreward and seaward consistency test data 

 sets have similar coefficients and are described by the same type of equation. 

 This favorable comparison between the form of the vertical flux data measured 

 with closely spaced traps indicates that the streamer trap and nozzles are 

 indeed consistent and provide reproducible measurements of the transport rate. 



Future Study 



123. Consistency tests between streamer traps with C, SUPERDUCK, and 

 DUCK85 nozzles (and the H-S sampler) will be conducted at the GL88 field data 

 collection project. A C trap and another nozzle trap will be deployed in 

 either the longshore current, if it is sufficiently strong, or next to a 

 shore-perpendicular structure where the longshore current is expected to be 

 concentrated and deflected offshore. Many tests will be conducted to give an 

 indication of the test variability and ultimately a measure of relative nozzle 

 efficiency for a field condition. In addition, the development of scour 

 through time at each bottom nozzle will be quantified. 



124. Tests with a streamer trap (C, SUPERDUCK, and DUCK85 nozzles) near 

 an Optical Backscatter Sensor (OBS) (see Appendix A) in the surf zone are also 

 planned for GL88. Comparisons between trap-measured and OBS sediment trans- 

 port fluxes will give a quantitative indication of consistency between the 

 streamer trap (for nozzles collecting suspended material) and electronic 

 instrumentation. 



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