change significantly. Sand was continuously deposited at depths of -2.1 
and -2.2 feet and after 90 hours at -2.0 feet. After 125 hours a flat 
area developed to a width of 6.5 feet (1.98 meters) between the -1.9- 
and -2.0-foot contours. 
The movements of the -1.0-, -1.5-, and -2.0-foot contours along the 
three ranges are compared in Figure 35. No significant lateral variation 
occurred at -1.0 foot and the variations at -1.5 feet were large at only 
one time and no pattern developed (i.e., one range was not always seaward 
of the others). At -2.0 feet the variations on the flattest part of the 
profile were large, but again there was no consistent pattern. 
(b) Experiment 72B-10. Changes in the offshore zone are 
shown in Figures 16 to 20. Initially, considerable erosion occurred 
along range 5 (Fig. 18) at elevations -0.8 to -1.0 foot, which formed a 
steep slope at the upper part of the offshore and, along with deposition 
at -1.1 and -1.2 feet, a flat area between the -1.0- and -1.1-foot con- 
tours (around station 10). The -1.0-foot contour later moved seaward, 
and then the -0.9- and -0.8-foot contours progressively crossed to the 
seaward edge of the flat area, indicating a widening of that area. The 
-1.7- and -1.8-foot contours gradually separated and formed a flat area 
near station 16; these contours then moved seaward, further widening this 
flat area. These changes occurred along the other ranges, but at dif- 
ferent times and to different extents. 
Along range 1 (Fig. 16) the area near station 10 became flat at a 
lower elevation (-1.1 feet), and the -0.8-foot contour never moved sea- 
ward. The area near station 16 became flat néar the end of the experi- 
ment between the -1.4- and -1.6-foot contours. 
Along range 3 (Fig. 17) the area near station 10 developed into a 
flat area as along range 5, but the -0.8-foot contour never moved seaward. 
Near station 16 the flat area developed between -1.5 and -1.6 feet. 
Along range 7 (Fig. 19) the area near station 10 developed in a 
manner similar to range 5, but the flat area near station 16 first devel- 
oped between the -1.8- and -1.7-foot contours near station 18 and then 
grew toward station 16 with deposition at the -1.7-, -1.6-, and -1.5-foot 
elevations. 
Along range 9 (Fig. 20) the changes in the flat areas occurred as 
along range 7. However, a steeper slope developed between the two flat 
regions from 120 to 140 hours. 
The movements of the -1.0-, -1.5-, and -2.0-foot contours along the 
five ranges are compared in Figure 36. There was considerable variation 
in the seaward movement of the -1.0-foot contour, which began and ended 
first along range 9 and began and ended last along range 1. The -1.5-foot 
contour was generally more seaward along range 1 with little difference 
along the other ranges. Seaward of station 20 was an area of deposition 
along ranges 1 and 3, but not along the other ranges. 
59 
