period gives nearly the same wave steepness as a 10-percent increaise in wave height. However, at the depth 

 of the nearshore wave gage, the water depth is transitional, and the corresponding increase in wave 

 steepness was calculated (linear theory) to be about 14 percent. 



138. Representative model- to-model comparisons between tests T03 and TOT are shown on Figure 18 

 in model dimensions, and a complete set of profile comparisons is given in Figure ElO in Appendix E. 

 Other results are given in the appropriate appendices. Differences between the base case (dashed line) and 

 the test with decreased wave period (solid line) are not very apparent in the plots for 80 waves and 



370 waves. There was slightly more scouring of the berm along with evidence of greater offshore transport, 

 but not as much as in the case of increased wave heights. It was not until later in the experiment that 

 differences became more evident (see Figure 18 at 1,650 waves). 



139. As the test approached the equilibrium condition, ccise T07 exhibited greater movement of 

 sediment offshore and substantially more scouring in the bar-trough region. This was due primarily to a 

 change in the breaking wave dynamics brought about by the decreased wave period. It is also possible that 

 backwash from the wave runup on the impermeable slope influenced the wave breaking kinematics. 

 Generally, the differences in model profiles are similar to that observed for the perturbation of wave height. 

 This is not unexpected in light of the induced increase in wave steepness, and the similarities are examined 

 further in the following section. 



Equal H/wT Parameters 



140. The perturbation tests of wave height and wave period were designed so that test T04 (wave 

 heights increased 10 percent) and test TOT (wave period reduced 10 percent) had nearly equal values of the 

 fall speed parameter. The purpose in doing so was to compare the resulting profile evolution and to cissess 

 the relative importance of the fall speed parameter and the Froude scaling of the hydrodynamics. In 

 essence, this comparison represents the situation where the fall speed parameter was held constant in an 

 undistorted model, and the hydrodynamics were distorted from one case to the other to maintain H/wT 

 similarity. 



141. Representative comparisons between tests T04 and TOT are shown in Figure 19 with complete 

 comparisons given in Figure Ell in Appendix E. Visually, a good correspondence is seen between the 

 profiles on Figure 19, and it appears that a better match was obtained than in the two cases where the fall 

 speed parameter was increased by 10 percent and compared with the base-case profiles (see comparisons in 

 Figures IT and 18). Table 6 presents the RMS variation between profiles as calculated by Equation 13. 

 The top half of Table 6 lists the results in model dimensions, and the bottom half gives the same results 

 scaled to equivalent prototype dimensions. 



58 



