surf conditions, these waves after breaking will re-form and result in another 

 line of breakers near the shore. The height of the breakers farthest from 

 shore should be recorded. When the breakers are low and relatively close to 

 shore, it is fairly easy to estimate breaker height to the nearest tenth of a 

 foot. It is considerably more difficult, however, where the breakers are high 

 and the surf zone is wide. If it is not possible to estimate the breaker 

 heights because the waves are too large and too far from shore, this fact 

 should be noted in the "remarks" section of the LEO form. Special care should 

 be exercised by the observer to provide his best estimate since breaker height 

 is the primary parameter used for designing shore protection and coastal 

 structures and is also used in mathematical expressions to predict longshore 

 sand movement. 



e. Wave Angle (Blocks 22, 23, and 24) . The angle of wave approach at 

 breaking is determined by using the protractor provided on the reverse side of 

 the LEO form (Fig. 5). The protractor is held horizontally with the to 

 180° line oriented parallel with the shoreline. The observer then sights 

 along the direction from which the breaking waves are approaching shore and 

 records the appropriate angle from the protractor (Fig. 6). (The direction of 

 approach is perpendicular to the breaker crest.) The observer should be as 

 close to the shoreline as practical in order to make this observation; how- 

 ever, at times a better perspective can be obtained from a bluff or pier. 

 When making observations from the deck of a pier an alternative sighting 

 procedure can be used. The protractor is placed on the pier railing adjacent 

 to the breaker region and alined so that the to 180 line is oriented 

 perpendicular to the shoreline. (This is usually along the axis of the pier 

 if the pier is perpendicular to the beach.) The observer then sights along 

 the crest of a breaking wave and records the appropriate angle (see Fig. 7). 

 Note that this sighting will give the same angle as obtained on the beach 

 sighting described earlier. 



80 90 100 



-SHORELINE • SH0RELIN 



OBSERVER 



NOTE : If a pier is used for an observation platform : place 0- 180 line on the 

 rail parallel to the centerline of the pier, site along the crest of the 

 breaking woves and record the angle observed. 



Figure 5. Protractor on reverse side of LEO form. 



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