Figure 7 . Schematic of the streamer trap rack 



flexible filter cloth called a "streamer" was attached. Typically, seven to 

 nine streamers were mounted vertically on stainless steel racks and pointed in 

 the direction of flow. The polyester monofilament cloth allowed water to pass 

 through but retained sediment of nominal diameter greater than the 0.105 -mm 

 mesh, which encompasses sand in the fine grain size region and greater. 

 Orifices of the nozzles were located upcurrent of the racks and any sediment 

 clouds due to scour produced by the rack and trap operator. Observation 

 during operation indicated that scoured sediment at the rack did not move 

 upstream and into the streamers. Data collection was always performed in a 

 unidirectional current so that the streamer never reversed direction, a 

 situation which might cause collected sand to be lost. The concept of the 

 streamer- type trapping device for use in the nearshore was introduced by 



18 



