PART II: STREAMER TRAP 



16. The basic sand collection element of the streamer trap was develop- 

 ed in Japan to measure longshore sand transport rates in the surf zone (Katori 

 1982). The name of the apparatus derives from the mesh collection bags which 

 stream out with the current during operation. The device has been used in the 

 United States to measure cross -shore distributions of the longshore sand 

 transport rate (Kraus 1987; Kraus and Dean 1987; Kraus , Gingerich, and Rosati 

 1988, 1989), variations in longshore sand transport at a point (Kraus, 

 Gingerich, and Rosati 1989; Kraus, Gingerich, and Rosati in preparation), 

 sand transport rates in the offshore*; sand transport in a rip current (Kraus 

 and Nakashima 1987); and deposition of sand into a submarine canyon." In 

 Japan, modified versions of the streamer trap have been used to measure cross- 

 shore sand transport rates (Katori 1983) and the rate of wind-blown sand 

 transport in a large wind tunnel (Hotta 1988). In general, the streamer trap 

 can be used to measure sand- sized sediment transport in almost any quasi - 

 steady and unidirectional flow. 



Description of the Streamer Trap 



17 . The streamer trap consists of rectangular sand collection bags 

 vertically mounted on a rack (Figure 2). The collection bags (streamers) are 

 sewn of technical grade monofilament sieve cloth, and each streamer is 

 attached to a nozzle which functions to facilitate the flow of sand -laden 

 water into the streamer (Figure 3). Sand of nominal diameter greater than the 

 mesh is collected in the streamer while water flows through the bag. 

 Streamers are made approximately 1.5 m long to ensure that long-period 

 deployment and/or deployment in high- transport regimes will not cause the 

 streamer to fill and thereby reduce its sand-trapping efficiency. A long 

 streamer also prevents loss of collected material if the flow momentarily 



Personal Communication, 1986, Jim Clausner , Hydraulic Engineer, 

 US Army Engineer Waterways Experiment Station, Vicksburg, Mississippi. 



Personal Communication, 1987, Craig Everts, Moffatt and Nichol . 

 Engineers, Long Beach, California. 



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