A22 



amplitudes at the wave generator location (TR 3) vary with incident wave 

 direction and wave period. For some angles, wave amplitudes along TR 3 

 were less and for others they were substantially higher than amplitudes off- 

 shore. It was found that, for example, for 0-deg incident waves, the maximum 

 wave amplification along TR 3 (i.e., the largest wave amplitude occurring on 

 at least one of the 25 grid points for TR 3) occurred as follows: 10 percent 

 for the 5-sec wave period (T), 30 percent for T = 7 sec, 90 percent for 

 T = 9 sec, 40 percent for T = 11 sec, percent for T = 13 sec, and 10 percent 

 for T = 15 sec. The five transects close to the beach north of the north jetty 

 (TR 1, TR 2, TR 5, TR 6, and TR 7) all appeared to experience equal or less 

 amplification of the wave amplitude for this wave angle. The highest amplifi- 

 cation (180 percent) along TR 3 occurred for -13-deg and -22.5-deg incident 

 wave angles. Wave period also seemed to play an important role in the ampli- 

 fication of nearshore waves. 



However, care should be exercised in interpretation of plots, particularly for 

 the TR 3. For this transect, the 10 grid points nearest to the transect line 

 among the 25 total grid points listed in tabular form have been selected for 

 plotting. Qjnsequently, the x-axis corresponds to grid points so chosen, and 

 the spacing on the x-axis is the distance between these selected nodes, and not 

 the distance along the transect. For five other transects, the x-axis represents 

 the true grid distance. Combined wave height-water depth plots are useful to 

 examine the spatial variation of wave amplitudes as waves propagate from one 

 point to another. Since these line plots provide more direct information about 

 wave height change than the contour plots covering the entire modeling area, 

 they were used in the earlier phase of numerical study. As tabular output was 

 preferred for the physical modeling study, plots were discontinued in the later 

 phase. 



The nearshore wave model REFDIF could not be calibrated or verified 

 since no measured wave data of high quality were available over an extended 

 period in the immediate vicinity of the Saco River jetfies. 



The 20-year WIS hindcast for Saco Bay was next applied to the SneU's law 

 wave transformation using linear wave theory. Wave period and direction 

 combinations with imit amplitudes were input into another computer program 

 developed during this study to create corresponding arrays of amplitudes, peri- 

 ods, and directions for each point in the grid. Subject to the assumptions for 

 Snell's law and linear wave theory, hindcast-based input wave data were trans- 

 formed from deepwater to selected depths along six transects in Saco Bay. 



Results from the application of Snell's law were presented only in tabular 

 form similar to those for REFDIF model predicfions. Addifional information 

 fisted in tables for Snell's law output included shoaling and refraction 

 coefficients. Deepwater incident wave parameters were designated by AMPO, 

 DIRO, and PERO, while the computed wave parameters were designated DEP 

 (local depth), AMP (local wave amplitude), PER (wave period), IBRK (wave 

 breaking index), KS (shoaling coefficient), and KR (refraction coefficient). 



Appendix A Saco Bay Nearshore Wave Estimates 



