a combined swell and local sea condition existed. Associated with the local sea 

 was the occurrence of an essentially shore-parallel wind-driven current. The 

 wind-driven current (average surface velocity = 18 centimeters per second), which 

 was documented with dyes, existed from the offshore at least up to the edge of 

 the surf zone (Fig. 4). Inside the surf zone, the longshore current velocity, 

 also measured by dyes, was 40 centimeters per second and in the same direction as 

 the wind-driven current. 



A current meter study was conducted on 24 July under conditions very similar 

 to those on 21 July. General oceanographic conditions during the test were 

 average breaker height = 0.55 meter, breaker period = 5.7 seconds, breaker (or- 

 thogonal) angle = 13 (south of normal) , and longshore current speed = 41 centi- 

 meters per second from the southwest. Both a swell and a local sea existed. 

 Wind velocity was - 23 kilometers per hour and essentially shore parallel at 

 the time of the experiment. Current meter measurements (1 meter above the bed) 

 showed average shore-parallel speeds of 40 to 50 centimeters per second in the 

 surf zone and average wind-driven current speeds generally exceeding 15 centi- 

 meters per second in the adjacent offshore zone (Fig. 12). 



Wind and wave conditions similar to those associated with the measured wind- 

 driven currents were observed to occur somewhat frequently during the study 

 period. 



150 200 250 300 350 400 450 

 Oiitonce froffl Bo«t Line (m) 



500 



Figure 12, Shore-parallel current speeds measured across the nearshore zone on 

 24 July 1960. The data points on each vector represent percentile 

 levels of the current speed distribution. The lower diagram shows 

 the profile shape and the general bed-form type across section A-A. 



23 



