The conclusions and recommendations (Sec. V) are directed toward the 
problems of the laboratory researcher or engineer in charge of a model 
study. Field engineers should be aware of these conclusions and recom- 
mendations when discussing and analyzing model studies of their projects. 
The data in this study (particularly the profiles) may have other 
uses. The researcher can use these data, after consideration of the 
- laboratory effects, to analyze short- and long-term changes in profile 
shape. After an analysis of the scale and laboratory effects, the 
field engineer may use these data to determine generalized profile 
adjustment rates. 
II. RESULTS 
1. Wave Height Variability. 
a. Incident Wave Heights. Wave height measurements from the 
continuous recording of water surface elevation along the center range 
at station +25 during the first 10 minutes of each experiment are shown 
in Table 4. The wave heights in the movable-bed tanks varied from 0.29 
to 0.46 foot (8.8 to 14.0 centimeters) in experiment 72A-06, and from 
0.17 to 0.33 foot (5.2 to 10.1 centimeters) in experiment 72A-10. 
Ignoring the first group of waves, the range of wave heights within the 
first 10 minutes was 0.15 foot (4.6 centimeters) in both experiments. 
In the fixed-bed tanks, again ignoring the first group, the range of 
wave height variation was 0.09 foot (2.7 centimeters) in experiment 
72A-06 and 0.10 foot (3.0 centimeters) in experiment 72A-10. The range 
of wave height variation was greater in the movable-bed tanks than in 
the fixed-bed tanks. 
The average wave height in the movable-bed tanks for each record 
(Table 4) was determined by averaging the average of the last 10 waves 
in each of the 40-second intervals after 40 seconds. In experiment 
72A-06 the average wave height was 0.39 foot (11.9 centimeters); in 
experiment 72A-10 the height was 0.24 foot (7.3 centimeters). Because 
the waves were recorded at the same distance from the movable-bed 
profiles, and assuming that the initial reflectivity was the same, the 
difference in the average wave height was not due to reflection from 
the profile, but likely due to the secondary waves and re-reflection 
from the wave generator, which can be affected by differences in initial 
test length. In the fixed-bed tanks the average wave height was 0.31 
foot (9.4 centimeters) in experiment 72A-06 and 0.36 foot (11.0 centi- 
meters) in experiment 72A-10. The difference between the two fixed-bed 
tanks was also likely due to differences in initial test length, because 
the gages were the same distance from the concrete slopes. 
The average wave height in the fixed-bed tank was 0.08 foot (2.4 
centimeters) greater than in the movable-bed tank for experiment 72A-06, 
and 0.12 foot (3.7 centimeters) less than in the movable-bed tank for 
experiment 72A-10. 
