Experiment Arrangement and Measurement Techniques 



Surf zone waves and water level 



17. The wave height distribution across the surf zone was measured by 

 filming the water surface elevation at 14 target poles made of steel pipe 

 (numbered PI to P14 in Figure 2) jetted into the sea bottom on a line crossing 

 the surf zone. The poles were spaced at nominal 20-ft (6-m) intervals and 

 painted a fluorescent yellow color to facilitate reading of the films. These 

 poles, called "photopoles" by CERC researchers, each had two short rods placed 

 horizontally near their top ends and separated by a known distance to cali- 

 brate the wave height measurement. Figure 4 shows the photopole line during 

 DUCK85. Pairs of photopoles were filmed with six synchronized 16-mm 

 professional -grade movie cameras mounted on a 4.5-m-high scaffold located on 

 the beach about 125 m to the south of the photopole line. The cameras were 

 run in the pulse mode at 5 Hz for a nominal duration of 12.5 min which 

 included a sand trap run. Ebersole and Hughes (1987) describe the DUCK85 

 photopole experiments and results. 



Figure 4. Photopole line spanning the surf zone 



15 



