The SPM presents a set of smooth-slope runup curves based princi- 

 pally on Saville (1956) and Savage (1958; 1959). Relative depth 

 (dg/H^) effects are included in the set of curves, but are given as 

 ranges of values. The data were reanalyzed for this study to determine 

 runup curves for specific dg/H^ values. Having such specific condi- 

 tions not only allows direct runup comparisons with rough-slope data 

 for the same wave conditions and structure geometry, but allows better 

 interpolation between sets of curves for intermediate dg/H^ values, 

 and allows calculation of specific values of the alternate relative 

 depth, dg/gT 2 . The smooth-slope design curves are discussed below. 



b. Smooth Structure Fronted by Horizontal Bottom . Only limited 

 runup data were obtained by Saville (1956) and Savage (1959) for a 

 structure on a horizontal bottom in depths dg/H^ < 3.0. However, much 

 data were obtained for dg/H^ > 3.0. The SPM provides only one set of 

 curves for dg/H^ > 3.0 which tends to give conservative results (high 

 predictions) for large d g /H' values. It is incorrect (although 

 stated in some recent studies) that depth effects are not present for 

 dg/H^ > 3.0. Figures 14, 15, and 16 give relative runup for dg/H^ 

 values of 3.0, 5.0, and 8.0. Larger values were not used because a 

 requirement for large dg/H^ values would be rare; when such a require- 

 ment occurs (e.g., in a reservoir), the set of curves for d s /H^ = 8.0 

 should be used. When runup values are required for d s /H^ < 3.0, the 

 curves for dg/TLJ, = 3.0 should be used. 



Relative depth effects are negligible for a particular wave steep- 

 ness in those instances when waves are breaking on the structure slope. 

 This observation has been made by various researchers. It can also be 

 shown by examination of the design curves; e.g., a comparison of Figures 

 14, 15, and 16 for H<J/gT 2 = 0.0124 shows that, for cot 6 > 3.0, all 

 three figures have approximately equal relative runup for a particular 

 slope. 



c. Smooth Structure Fronted by 1 on 10 Beach Slope and Zero Toe 

 Depth (dg =0). A structure with zero toe depth (d s = 0) presents a 

 special case in that relative depths seaward of the beach slope are 

 not adequately specified by dg/H^ = 0. Therefore, in the case of zero 

 toe depth, wave conditions are specified using the depth, d, at the 

 toe of the beach slope. Figures 17, 18, and 19 present the results for 

 d/H^ (not dg/H^) values of 3.0, 5.0, and 8.0 with a 1 on 10 bottom slope. 



d. Smooth Structure Fronted by 1 on 10 Beach Slope and Toe Depth 

 Greater than Zero (dg > 0). Design curves based on small-scale runup 

 data (Saville, 1956) for a smooth structure fronted by a 1 on 10 beach 

 slope are given in Figures 20 to 23. The basic data were obtained 

 principally for cases where the relative beach-slope length, t/L, was 

 equal to or greater than one-half (this limit is shown in the figures). 



41 



