Immediately after the wave data were collected, dye was injected into the 
surf zone, as discussed in Section III, and the leading edge of the dye was 
timed over a distance of approximately 4 meters (see Table 2) to determine the 
longshore current velocity. Also recorded were the station at which the dye 
left the downdrift edge of the beach and the station at which the waves were 
breaking. Therefore, the determination of whether the dye moved offshore, 
along the breaker line, or onshore could be madee Most of the dye injections 
traveled along the breaker line. 
During the hourly cycle, sand was continually picked up from the trap area 
and weighed when a bin was full. A complete record of the amount of sand 
moved in a given time period existed only at the end of the day after the 
waves had been stopped and all the remaining sand had been picked up and 
weighed. Therefore, the longshore transport rate can be given for a daily 
cycle or a test cycle only. 
2. Daily Cycle. 
At the start of every test day (see Fig. 14), the water temperature was 
recorded, the water level was corrected to 0./10 meter, the wave gages were 
calibrated, and a check of all equipment was made. The hourly cycles were 
then started. Four hourly cycles were usually completed each day. 
Shortly before the waves were turned off at the end of the day, photos of 
the surf zone were taken from the side (see Fig. 18 for examples). After the 
waves were stopped, all the sand in the sand trap, on the downdrift concrete 
apron, and in the downdrift deposition area was moved to the weighing station 
and weighed. The day's longshore transport movement was then determined after 
the final weighing. This quantity, divided by the total number of run-hours, 
provided the immersed weight longshore transport rate for the day. 
3. Test Cycle. 
At the beginning of each test, new test values for the wave period, T, 
the generator angle, a,, and the generator eccentricity, Ecc, were 
selected and set (Fig. 14). Ecc is half the distance the generator bulkhead 
movese The combination of period and eccentricity produced a predicted wave 
height, using the calibration curve of the generators (see Fige 2 in 
Fairchild, 1970). This guided the selection of T and Ecc but was not used 
for wave height determination. 
The beach was regraded to the shore-normal profile (see Fig. 6) before 
each new teste This included raking the beach to remove all traces of ripples 
from the prior test. The basin was usually flooded to cover the entire beach 
and left over a weekend to allow the new beach to stabilize before the new 
test cycle began. 
After the test was completed, the basin was drained in 10-centimeter 
increments, producing depth contours of 0, 10, 20, 30, 40, 50, and 60 
centimeters. An overhead photo of the waterline was taken at each 
increment. An example series is shown in Figure 19. Surveys of the beach 
were then taken, using a standard level and rod, along ranges 1.5, 2, 3, 4, 5, 
6, 7, and 7.6 meters. The elevation on each range was read at all major 
breaks in slope. 
28 
