70X-06 is shown in Figures 22, 23, and 24; the movement of selected indi- 

 vidual contours along the three ranges is compared in Figure 25. 



During the first 10 minutes of testing a bar formed at station 4 by 

 plunging breakers, and within 4 hours the elevation of the bar had reached 

 -0.3 foot (triangles in Figs. 22, 23, and 24). Between 4 and 8 hours the 

 bar moved shoreward and then remained at station 2 until 22 hours. After 

 22 hours the bar moved seaward to station 2.5 and the elevation fluctuated 

 between -0.3 and -0.4 foot, as indicated in the figures by the shifting 

 of the seawardmost contour for -0.3 foot. After 54 hours the bar disap- 

 peared, evidenced by the shoreward movement of the -0.4-foot contour. 

 The inner region maintained a fairly stable, gently sloping shape from 66 

 to 135 hours and after 135 hours developed a steep slope (close spacing 

 of the -0.2-, -0.3-, and -0.4-foot contours in Figs. 22, 23, and 24). 



The movements of the -0.2- and -0.4-foot contours are compared in 

 Figure 25. No lateral variation apparently occurred in the changes of 

 the inner region, other than minor differences in the elevation of the 

 bar crest between 22 and 54 hours (see comparison of the -0,2- and -0.4- 

 foot contours for the three ranges in Fig. 25). 



(b) Outer Region (Experiment 70X-06) . During the first 22 

 hours little change occurred in this region, only the slight erosion evi- 

 denced by the retreat of the -0.5-foot contour (Figs. 22, 23, and 24) as 

 the bar formed in the inner region. After 22 hours the deposition of sand 

 in the offshore was sufficient to move the -0.8-foot contour in the sea- 

 ward direction and thus form a nearly flat shelf between the 0.5- and 0.8- 

 foot depths. After the large deposition between 22 and 26 hours (seaward 

 movement of the -0.6-, -0.7-, and -0.8-foot contours), the shelf in the 

 outer inshore continued to grow as more material was deposited offshore, 

 as indicated by the seaward movement of the -0.8-foot contour. The shore- 

 ward movements of the -0.5- and -0.6-foot contours follow the erosion of 

 the bar in the inner region and result in the further development of the 

 flat shelf in the outer region. 



The shoreward edge of the shelf or outer region stabilized after 66 

 hours, and the seaward edge (-0.8-foot contour) reached equilibrium at 

 100 hours. After 100 hours, the seaward movements of the -0.6- and -0.7- 

 foot contours indicated that some material was being deposited in this 

 outer region. What might be considered small bars (difference between 

 crest and trough elevations was generally less than 0.2 foot) were formed 

 at stations 8.5 and 4.5 (Figs. 22, 23, and 24). 



The only significant lateral variations in this outer inshore was the 

 depth over the bars at stations 8.5 and 4.5. After 135 hours the elevation 

 of the bar at station 4.5 was -0.5 foot along range 1 (Fig. 22), -0.6 foot 

 along range 3 (Fig. 23), and -0.7 foot along range 5 (Fig. 24); the eleva- 

 tion at station 8.5 was generally -0.7 foot, but at different times along 

 the three ranges reached an elevation -0.6 foot. The movements of the 

 -0.6- and -0.7- and -0.8-foot contours along the three ranges (Fig. 25) 

 show that lateral variations are quite small. 



50 



