22. The collected sand can be weighed and its dry weight estimated on 

 the beach using a linear relationship between drip-free wet weight and dry 

 weight of cohesionless sand found by Kraus and Nakashima (1986): 



DW = C WW (1) 



where 



DW = dry weight of sand 



WW = wet weight of sand 

 C = empirical coefficient, typically ranging from 0.77 to 0.83 

 It is recommended that some samples from each test be retained for laboratory 

 calibration of C , because its value depends on the weighing procedure (the 

 balance operator's judgement of the drip-free condition) and the nature of the 

 sand. The clean streamers can then be secured onto the rack and the traps 

 prepared for another sampling sequence. Use of a vertical array of streamers 

 results in a sand flux and grain size distribution at each elevation. 



23. In field data collection projects conducted at Duck, North Carolina 

 (Kraus and Dean 1987; Kraus, Gingerich, and Rosati 1988, 1989), two to four 

 complete longshore testing sequences were conducted per day. Kraus (1987) 

 also describes the streamer trap and its use in the surf zone. 



Other field data collection 



24. Use of the streamer trap is not limited to longshore sand transport 

 collection experiments. Other types of surf zone sand transport experiments 

 in which streamer traps have been used include measurement of sand transport 

 rates in two longshore current feeders and the throat of a rip current (Kraus 

 and Nakashima 1987), comparison of sand collected with two closely spaced 

 traps (consistency tests) (Kraus 1987) (detailed in Part V), measurement of 

 cross-shore sand transport rates (Katori 1983), and point-measurements of sand 

 transport through time (Kraus, Gingerich, and Rosati 1988, 1989). 



Calculation of Sand Transport Rate 



25. Figure 6 defines the variables used in the sand transport rate 

 calculation. The weight of sand collected in streamer k is S(k). The 



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