3. Survey Data. 
After each test, the SPTB was drained and the beach was surveyed. The 
distance and elevation pairs are listed in Appendix B and plotted in Appendix 
C. The elevation datum is the stillwater level (SWL), which corresponded to a 
0.710-meter water depth. 
4. Overhead Photos. 
Every hour during testing, the waves were stopped to take an overhead 35- 
millimeter photo of the beach (see Fige 15). The photos show the waterline, 
the longshore bar, and the swash zone. They are useful for a qualitative 
description of how the beach responded to the waves. Appendix D contains a 
series of photos for run-times 01 00, 08 00, 16 00, and 24 00. 
VI. DATA ANALYSIS 
This section includes the data analysis to determine the relations between 
Ip and S,, and I, and Po,e The empirical coefficients found from these 
relations are then, in turn, related to the surf similarity parameter, €, 
which is adapted to the data collected. Also included is an explanation of 
the calculations of S,., Ppp, &, and I,, along with plots of the various rela- 
tionships. The wave Benet used in the calculations is that measured at the 
toe of the beach (average of gages 1 and 2 wave heights). The breaker wave 
height, which would have been a better value, was not used for the following 
reasons. The wave height at the toe of the beach was measured for all 15 
tests; the breaker height was not. Also, only one gage was used to measure 
breaker height, while two were used at the beach toe. The significant differ- 
ence in height between waves measured at the two beach toe gages (see App. A) 
indicates that some wave height variability existed along the wave crest. 
Therefore, the average of the measurements at the two beach toe gages is 
probably a more reliable estimate of the entire wave passing the toe than the 
one gage measurement at the breaker is of the entire breaker waves A compar- 
ison of the data in this report with past studies is shown in a Q _ versus 
Pop graph. 
1. Calculation of Sxy? 
Equation (7) 
2 A 
xy 8 g C 
was used to calculate Sxy* Rearranging the equation, 
Sg = ao an sin 2a @2i15) 
where n is the ratio C,/C and a function of the water depth and wave 
period or length. Sx was calculated at the toe of the beach by using the 
average of the wave heights measured at that location (see Fig. 7), and by 
using the generator angle for a. This was calculated for each set of wave 
data. Thus, for the standard 24-hour test, 24 values of 5S, were calculated 
(see Appe E)- The average of Sxy for each test is listed in Table 5. 
35 
