and was very gradually decreasing; after 95 hours, K^> fluctuated be- 

 tween 0.06 and 0.14 and, in general, increased. 



While K^ was fluctuating so greatly during the first 31 hours, the 

 foreshore developed and eroded landward, a longshore bar developed, the 

 bar and the plunging breaker moved landward and then seaward, and (after 

 26 hours) the offshore zone began to steepen (Table 4). All of these 

 profile and breaker changes could have contributed to the K^> variations 

 during that time. Between 33 and 95 hours, when K^> was less variable 

 and very gradually decreasing, the foreshore position stabilized, the 

 breaker type changed to spilling (and thus no longer reflected any energy) 

 the longshore bar eroded (and thus was no longer a reflector) , and the 

 offshore slope gradually steepened at the base and prograded slowly sea- 

 ward (and thus the phase difference between waves reflected from the two 

 zones may have gradually changed). A change of 4.5 feet (1.4 meters) 

 between the foreshore and offshore would have caused a 360° change in 

 phase difference. After the shelf developed, the distance between the 

 0- and -1.5-foot (45.7 centimeters) contour increased only 1.9 feet 

 (57.9 centimeters). 







Table 4. Surji^ry 



of profile dev. 



lopment in experimcr 



t 70X-06. 







Tiaa 

 (ht> 



Foreshore 



Inner inshore 



Outer inshore 



Offshore 



Breaker conditions 



■ater tecperatur* 



Depth (ft) 



Type' 



Olo I 



developed 

 ■hup* 



bar formed 





deposition > 1.1 ft 



o.s 



' 



28 to 30 



1 to S 



■vg. erosion nt« 

 Of 0.06 ft/hr 



elevation of bar 

 mcreased to -0.3 ft 



O.S 



9 



25 to 26 



5 to 1 



bar -oved shoreward. 



deposition > ft. 8 ft 



0.5 



' 



24 to 27 



'"» 



(depth and position) 





O.S 



' 



26 to 30 



22 to 26 



avg. erosion rate 

 of 0.14 ft/hr 



depth 0.4 ft 



large 



deposition at 

 depths of 

 0.7 and 0.8 ft 



0.9 ft 



O.S 



P 



28; drop to 18 



26 to 30 



depth varied 0.3 to 0.4 ft 



0.8 ft 



It 1.1 end 1.0 ft 



O.S 



P 



17 to 18 



50 to 40 



0.10 





position moving 

 0.6-ft depth 



P 



17 to 20 





0.6 



changed froa 

 P to SP 



21 



*4 to S4 



SML stable erosion 

 of last of scarp 



0.S and 0.6 ft 



0.6 



SP 



21; drop to 16 



54 to 66 



fill started 

 erosion of 

 fill «< .vg. 



bar eroded 



0.S ft 



■HUt. to 



0.7. ft depth 



SP 



14 to 18 



66 to 90 



erosion < .vg. 





stabilized for 

 remainder 



0.7 



SP 



" "° lS; ' rop " " 



90 to 100 



erosion » .vg. 





0.7 



SP 



" 



1D0 to 135 



erosion • .vg. 



sea-.rd edge 



deposition > 0.9 ft 



0.7 



SP 



11; rise to IS; 



135 to 140 



v".i°" iisr 1 



0.6 and 0.7 ft 



0.7 



SP 



• 



140 to 175 



stable slope ,0.7-ft depth at 





0.7 



SP 



7 to 10; ftvg. 8 



175 



(■edian 

 grain tii* 



range 0.34 to 0.56 

 •vg. 0.39 



0.27 to 0.33 



0.26 to 0.31 

 0.28 



0.:2 to 0.29 

 0.25 









'P ■ plunging; SP ■ spi 1 1 mg-plungii 



23 



