Reversals in current direction occurred during almost any given 

 month at each locality (Fig. 32) . However, a definite seasonal pattern 

 of reversals is evident at Boca Raton where the data were collected most 

 frequently. The seasonal change in direction at Boca Raton indicated for 

 monthly averages of wind and waves (Fig. 31) is confirmed by the longshore 

 current data in Figure 32. At Boca Raton, currents flowing to the north 

 dominate during April through August. Currents to the south dominate 

 during September through February. Seasonal reversals are not as clear 

 at Jupiter and Hollywood, which is probably a result of the less frequent 

 observations. However, there is a definite tendency toward southerly 

 currents during the winter months. 



The annual vector sum of all longshore current velocity measurements 

 is small and directed to the south. At Jupiter, it is 0.22 foot (0.07 

 meter) per second to the south, and at Boca Raton and Hollywood it is 

 effectively zero (0.02 and 0.01 foot (0„006 and 0.003 meter) per second, 

 respectively). The direction and the relative ordering of the vector 

 sums agree with the direction and relative ordering of longshore trans- 

 port rates at the three sites (Table 3) (U.S. Army, Corps of Engineers, 



Table 3. Longshore transport estimates. Units are in cubic yards per year. 





U.S. Army, 



Corps of Engineers 



(1971)' 



Walton 

 (1973)23 



This study 



Locality 



Galvin 

 (1972) 



Das 

 (1972) 



SPM 



(1975) 



Jupiter 





(St. Lucie) 



700,000 



94,100 



S. 



1,545,680 



1,459,188 

 536,592 



S. 



2,342,248 



674,027 



Npt 



230,000 



S. 













Boca Raton 



(HiUsboro) 



(HiUsboro) 

 711,000 

 315,000 



S. 



768,320 



986,765 

 -10,246 



N. 



1,565,017 

 -14,031 



N 



Net 



120,000 



S. 













Hollywood 



(Port Everglades) 



(Port Everglades) 

 727,000 

 259,000 



S. 



492,980 



416,463 

 -9,780 



N. 



628,658 

 -177,990 



N. 



Npt 



50,000 



S. 



Direction 





Based on impoundment and dredging records. 



Estimates of potential transport which are probably not reached because of underlying coquina. 



Computation based on U.S. Army, Corps of Engineers, Coastal Engineering Research Center (1966). 



Currents to the south were observed 53 percent of the time at Jupiter, 

 42 percent at Boca Raton, and 47 percent at Hollywood. Currents to the 

 north occurred 34 percent at Jupiter, 40 percent at Boca Raton, and 39 

 percent at Hollywood, with "calm" conditions accounting for the remt 

 observations. 



remaining 



52 



