PART V: FIELD EFFICIENCY TESTS 



110. The streamer trap has performed successfully in two major field 

 data collection projects as well as in smaller scale field experiments. In 

 particular, longshore sand transport rate measurements were made at DUCK85 

 (Mason, Birkemeier, and Howd 1987) and SUPERDUCK projects. These projects 

 were named for the village of Duck, North Carolina, located near the Field 

 Research Facility (FRF) of the Coastal Engineering Research Center. Use of 

 the streamer trap in data collection to be conducted on Lake Michigan during 

 September 1988 (Great Lakes '88 (GL88)) is also planned. 



111. Two types of longshore sand transport data have been collected 

 with the streamer trap: the distribution of longshore transport across the 

 surf zone using a spatial sampling method (SSM) (Kraus and Dean 1987), and the 

 variation of longshore transport through time at a point using a temporal 

 sampling method (TSM) (Kraus, Gingerich, and Rosati 1988). SSM runs involved 

 simultaneous deployment of traps on a line through the surf zone, resulting in 

 the measurement of vertical and cross -shore distributions of longshore sand 

 transport. During the data collection projects performed at the FRF, 

 typically 7 to 10 traps were placed on a line crossing the surf zone for a 5- 

 to 10-min data collection period. TSM runs resulted in vertical distributions 

 of sand transport at a point over an extended period (typically 30 min to 



1 hr). A single streamer trap typically collected transport data for a 5- to 

 10-min period at a particular point in the surf zone, then it was replaced 

 with another trap positioned at the same general location for a similar time 

 interval . 



112. During the DUCK85 and SUPERDUCK data collection projects, tests 

 were conducted to evaluate the behavior of the streamer trap in the prototype. 

 An indication of trap reliability was assessed by comparing sand transport 

 rates collected with two closely-spaced traps. These so-called "consistency" 

 tests involved measuring sand transport with two traps positioned approximate- 

 ly 1 m apart both in the cross -shore and longshore directions. In addition, 

 qualitative characteristics of nozzle behavior in the surf zone were noted 

 during the consistency tests and the TSM and SSM runs. 



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