will discuss types of coastal measurement apparatus and studies associated 

 with each. 



Suspended load apparatus 



13. Devices developed to measure suspended load in the nearshore zone, 



similar to riverine suspended sediment samplers, can be classified as either 



instantaneous, integrating, or indirect-measuring. 



a. Instantaneous . Instantaneous bulk (in situ) samplers are 

 similar to the riverine Eakin multiple samplers (Figure A3) 

 consisting of a vertical array of cylinders that collect a bulk 

 water-sediment sample when triggered. An in situ sampler 

 developed by Kana (1976, 1977; Kana, Ward, and Johnson 1980) 

 for use in the surf zone consists of five 2-liter acrylic tubes 

 with hinged doors mounted vertically on a 2-m-long pole (Figure 

 A13). When the sampler is thrust into the bed, a foot-pad 

 assembly triggers hinged doors that close the acrylic tubes, and 

 samples are collected in approximately 0.5 sec. Surf zone 

 studies have been conducted at Price Inlet, South Carolina, and 

 Duck, North Carolina, with a line of samplers spaced across the 

 width of the surf zone. Trap operators hold the device above 

 the water level until the passage of the wave crest, at which 

 time the sampler is thrust into the bed. The bulk samples can 

 then be carried in the sampler back to the beach. Tests are 

 conducted to determine the degree to which sampler operation 

 suspends additional sediment. Samples are taken by gently 

 placing the sampler on the bed and compared with violently "pole 

 vaulting" the device to collect samples. The size distributions 

 and quantities of suspended sediment were not significantly 

 different, indicating that operation of the sampler does not 

 place sediment in suspension. Tests with two samplers in close 

 proximity also gave results in close agreement, indicating that 

 the samplers are consistent (Kana 1976). Suspended sediment 

 transport measured with the samplers at Price Inlet, South 

 Carolina, was 95 percent of that predicted by the Coastal 

 Engineering Research Center (CERC) formula ( Shore Protection 

 Manual 1984) (Kana 1977); storm measurements at Duck, North 

 Carolina, agreed with the CERC formula, whereas post- storm 

 transport rates were 30 percent of the predicted quantities 

 (Kana et al . 1980). The use of a similar sampler called the 

 "water coring" device is slightly different: the sampler is held 

 in the surf zone prior to triggering, allowing water and 

 sediment to flow freely through the chambers until samples are 

 collected. Motion pictures of the sampler with confetti to 



A21 



