Wave Period (Blocks 16, 17, and 18). 



Wave period is recorded as the 

 crests to pass an arbitrary, fixed 



number of seconds it takes for 11 wave 

 point in the surf zone (Fig. 3). Timing begins when the 1st crest passes the 

 point and ends when the 11th crest passes the point; the time for 10 waves to 

 move past the point is then recorded. All waves, whether large or small, 

 should be counted. If no waves are present, a zero representing calm condi- 

 tions is recorded. 



d. Breaker Height (Blocks 19, 20, and 21) . This observation is based on 

 the observer's visual estimate of the average height of the breaking waves 

 (Fig. 4). Natural or manmade features with known dimensions along the shore- 

 line or in the surf zone can be used to aid in making this estimate. A visual 

 estimate of the average breaker height representative of conditions in the 

 seawardmost major breaking zone is recorded to the nearest tenth of a foot. 

 Observers should also attempt to estimate the breaker height of the seaward- 

 most line of breakers. These are generally the largest breakers. Under some 



Figure 3. Timing the wave period. 



HEIGHT AT BREAKING 



/ 



Figure 4. Visually observed estimate of breaker height. 



11 



