are very limited; brief qualitative comments regarding runup in such 

 circumstances are given in later sections. 



The incident wave characteristics seaward of the toe of the bottom 

 slope are partly determined by the corresponding water depth and are 

 important in determination of runup. The methods presented in Sections 

 11,2 and 11,3 are designed to account for the incident wave character- 

 istics at the toe of the bottom slope as determined in model experiments. 

 Natural underwater slopes are rarely so well defined; straight-line 

 approximations of irregular slopes should be determined by the designer. 

 Intersections of the straight lines will define the location of a change 

 in slope. 



II. RUNUP CURVES 



1. Smooth Structure Fronted by Horizontal Bottom . 



Relative runup, ^/^o' ^'^^ ^ smooth structure fronted by a horizontal 

 bottom is given in Figures 2, 3, and 4 for specific values of relative 

 depth, Aq/Wq. As shown by comparing the figures, relative runup on the 

 flatter slopes is not a function of dg/Fy. However, relative runup on 

 the steep slopes is sensitive to depth effects; relative runup for a 

 given wave steepness, H^/gT", is largest at the lowest dg/py value. 

 Thus, proper consideration of depth effects must be included in design. 



Relative depth values of 2 < dg/H^I, < 3 may occur for structures on 

 horizontal bottoms, but experimental data are limited. Figure 2 

 (dg/H^ = 3) is recommended for cases in which dg/H^ < 3. Large dg/H^ 

 values may occur, for example, in reservoirs; runup determinations for 

 dg/H^ > 8 should be based on Figure 4 (dg/H^J, = 8) . 



2. Smooth Structure Fronted by 1 on 10 Bottom Slope and Zero Toe 

 Depth (dg = 0) . 



When dg = 0, wave conditions are determined using the depth, d, at 

 the toe of the 1 on 10 bottom slope. Figures 5, 6, and 7 show the results 

 for d/H^ (not dg/H^I,) values of 3, 5, and 8 with a 1 on 10 bottom slope. 



Runup on a structure fronted by a beach slope flatter than 1 on 10 

 would be expected to be less than indicated in Figures 5, 6, and 7 for 

 comparable wave conditions. However, these figures are recommended for 

 use when a flatter bottom slope is present and dg = 0. 



3. Smooth Structure Fronted by 1 on 10 Bottom Slope and Toe Depth 

 Greater than Zero (dg > 0) . 



Design curves for runup on a smooth structure with dg > 0, fronted by 

 a 1 on 10 bottom slope, are given in Figures 8 to 11. The curves apply 

 to cases where the relative bottom-slope length is t/h t. 0.5. For values 

 of l/L < 0.5 but for high dg/H^ values (e.g., dg/H^^ >. 3), the runup 

 values from figures for structures on horizontal bottoms (Figs. 2, 3, and 



