representative of a profile adjustment for a 1.50-second wave. The pro- 

 files in experiments 72A-10 and 72B-06 were close to or at equilibrium 

 and are assumed to typify profile adjustment for 3.75- and 2.35-second 

 waves. These four profiles are compared in Figure 32. 



The profile from experiment 72A-10 (H /L = 0.004 at 80 hours) is 

 typical of the step-type or summer (prograding shoreline) profile, with 

 a high berm and a step at the toe of the foreshore zone. The profile 

 from experiment 72B-06 (H /L = 0.013 at 150 hours) is also somewhat 

 typical of the summer profile, except that the berm crest is lower and 

 the lower foreshore appears to be half-bar and half-step. On both of 

 these two profiles, some deposition occurred in the offshore zone, more 

 in the H (? /L = 0.013 experiment than in the H /L = 0.004 experiment. 

 The profile from experiment 71Y-06 (H /L = 0.021 at 375 hours) is cer- 

 tainly an eroding profile consisting of steep foreshore and offshore zones 

 separated by a long shelf with several shallow bars and troughs. The pro- 

 file from experiment 72C-10 (H /L = 0.039 at 140 hours) is typical of 

 the bar-type or winter (eroding shoreline) profile with a vertical scarp, 

 a steep foreshore, a longshore bar, and offshore deposition. 



The transition zone between the two types of profiles is normally 

 accepted to be between H /L = 0.020 and 0.025 and the profiles from the 

 five experiments with H /L = 0.021 could certainly not be classified as 

 either winter or summer. In fact, this was the least stable of the four 

 conditions, with none of the five profiles close to equilibrium. With 

 the other three wave steepnesses, at least one of the profiles appeared 

 to be near a stable shape. This agrees with the findings of Kamphuis 

 (personal communication, 1978) that waves in the transition region tend 

 to take longer to develop an equilibrium profile. 



The final profiles from experiments 72C-10, 71Y-10, 72B-10, and 

 72A-10 were averaged to develop a standard initial profile (Fig. 33) 

 to be used in longshore transport experiments in CERC's Shore Processes 

 Test Basin (SPTB) (P. Vitale, hydraulic engineer, CERC, personal communi- 

 cation, 1976). This standard profile will also be used in a study of 

 wier jetties in the SPTB (J.R. Weggel, Chief, Evaluation Branch, CERC, 

 personal communication, 1977). 



f. Discussion of Results . The four experiments with the 1.90-second 

 wave verify the findings of Savage (1962) and Fairchild (1970a) that an 

 equilibrium profile is not always easily attained, even with the wave 

 direction normal to the shoreline. The four experiments with the 3.75- 

 and 2.35-second waves verify the findings of Collins and Chesnutt (1975, 

 1976) that profiles for the same wave conditions do not always have the 

 same shape. In particular, the experiments with 3.75- and 2.35-second 

 waves point out that the physical constraints of the laboratory facilities 

 can affect the final profile shape. The currents in experiment 72A-06 

 (3.75 seconds) and the transverse wave in experiment 72B-10 (2.35 seconds) 

 kept those from reaching equilibrium. 



In judging the evidence presented here, profile equilibrium in basi- 

 cally two-dimensional tests does not appear to be an easily definable, 



73 



