7^ 



(a) Sctipps Canyon 



18 November 1948 

 Wave period 7-6 sec 

 Waves from WNW 

 — - ikn 



-♦ J - 1 kn 

 wm^ > 1 knoi 



— -^' Observed current 

 (noi measured) 

 • Starting position of 

 surface float 



Breaker height 

 ) Float fecovery area 



Figure 1. Nearshore current system at La Jolla Beach, California, December 

 1948 (from Shepard and Inman, 1951). 



Shepard and Inman' s (195(D) early observations of nearshore circulation 

 patterns and magnitudes in California were later confirmed and extended by 

 Harris (1964, 1967, 1969) in South Africa and Sonu (1969a) on the northwest 

 Florida coast. Sonu (1972), in a further analysis of these measurements, re- 

 ported shoreward currents of 20 to 30 centimeters per second and rip velocities 

 as high as 2 meters per second. Between these extremes, speeds gradually 

 changed. When circulation velocities were low, the rip current was broad with 

 no apparent root or stem visible. Sonu used weighted floats, dye, and a bi- 

 directional, propeller-type current meter to obtain time-series records of 



25 



