lateral variation in runup and the counterclockwise circulation. The 
distance between antinodes was approximately 12 feet (3.7 meters), 
which meant that the wavelength over the shelf was 24 feet (7.3 meters). 
The tank width of 6 feet was obviously a critical width (1/4 wavelength) 
and thus susceptible to this form of disturbance. 
c. Water Temperature. In experiment 72A-06 the shoreline retreated 
at a constant rate, which means that the volume rate of erosion was 
continually increasing as the water temperature gradually rose. In 
experiment 72A-10 the shoreline and the profile reached equilibrium, but 
the water temperature remained fairly constant. This suggests a possible 
temperature effect on the rate of sediment transport and profile adjust- 
ment; however, this is opposite to the effect reported in Volume II. 
V. CONCLUSIONS AND RECOMMENDATIONS 
1. Conclusions. 
(a) In two experiments with a water depth of 2.33 feet, a wave 
period of 3.75 seconds, and a generator stroke of 0.35 foot (generated 
wave height of 0.31 foot), the average incident wave height was 0.38 
foot in experiment 72A-06 and 0.35 foot in experiment 72A-10 (Table 5). 
Reflection measurements in the control tanks with a fixed-bed profile 
varied from 0.06 to 0.08 in experiment 72A-06 and from 0.02 to 0.07 in 
experiment 72A-10. This variation is taken as the inherent measurement 
error in determining Kp from the movable-bed profile (Table 6). 
(b) Kp varied from 0.17 to 0.31 in experiment 72A-06 (Fig. 5) and 
from 0.24 to 0.37 for the average of three ranges in experiment 72A-10 
(Fig. 6). The variation in Kp correlates well with profile changes. 
Kp increased as the profiles developed. As profile changes in experi- 
ment 72A-10 decreased, the increases in Kp slowed but Kp continued 
to vary for the remainder of the experiment. In experiment 72A-06 the 
Kp remained high while the offshore zone consisted of a flat shelf and 
steep seaward slope, but started declining as the offshore zone developed 
into a more gently sloping zone (Fig. 41). 
(c) The profile in the 10-foot tank developed an approximate 
equilibrium profile during’ the first 25 hours (Fig. (17))., ihel profile 
in the narrower tank developed a profile similar to the wide tank except 
that the offshore slope was much steeper; however, the profile continued 
to change and never appeared close to equilibrium (Fig. 13). 
(d) A strong circulation pattern developed in the narrow tank which 
did not develop in the wider tank. In the foreshore zone a counterclock- 
wise circulation developed, causing significant lateral variation in the 
shape of the foreshore zone. Over the flat shelf in the inner offshore 
zone, a strong clockwise circulation developed between the antinodes of 
the standing wave envelope (Fig. 39). The circulation in the inner 
offshore disintegrated coincidentally with the change of the offshore 
profile from a steep slope and flat shelf to a gently sloping region. 
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