can reasonably be assumed to occur simultaneously at the site. Where hurri- 

 canes cross the coast, high water levels resulting from storm surge and 

 extreme wave action generated by the storm occur together and usually provide 

 critical design conditions. Design water levels and wave conditions are 

 needed for refraction and diffraction analyses, and these analyses must follow 

 establishment of design water levels and design wave conditions. 



The frequency of occurrence of adopted design conditions and the frequency 

 of occurrence and duration of a range of reasonable combinations of water 

 level and wave action are required for an adequate economic evaluation any 

 proposed shore protection scheme. 



II. WAVE RUNUP, OVERTOPPING, AND TRANSMISSION 



1 . Wave Runup 



a. Regular (Monochromatic) Waves . The vertical height above the still- 

 water level to which water from an incident wave will run up the face of a 

 structure determines the required structure height if wave overtopping cannot 

 be permitted (see Fig. 7-7 for definitions). Runup depends on structure shape 

 and roughness, water depth at structure toe, bottom slope in front of a 

 structure, and incident wave characteristics. Because of the large number of 

 variables involved, a complete description is not available of the runup 

 phenomenon in terms of all possible ranges of the geometric variables and wave 

 conditions. Numerous laboratory investigations have been conducted, but 

 mostly for runup on smooth, impermeable slopes. Hall and Watts (1953) 

 investigated runup of solitary waves on impermeable slopes; Saville (1956) 

 investigated runup by periodic waves. Dai and Kamel (1969) investigated the 

 runup and rundown of waves on rubble breakwaters. Savage (1958) studied 

 effects of structure roughness and slope permeability. Miller (1968) 

 investigated runup of undular and fully broken waves on three beaches of 

 different roughnesses. LeMehaute (1963) and Freeman and LeMehaute (1964) 

 studied long-period wave runup analytically. Keller et al. (1960), Ho and 

 Meyer (1962), and Shen and Meyer (1963) studied the motion of a fully broken 

 wave and its runup on a sloping beach. 



Figures 7-8 through 7-13 summarize results for small-scale laboratory 

 tests of runup of regular (monochromatic) waves on smooth impermeable slopes 

 (Saville, 1958a). The curves are in dimensionless form for the relative runup 

 R/H' as a function of deepwater wave steepness and structure slope, where 

 R is the runup height measured (vertically) from the SWL and H' is the 

 unrefvaoted deepwatev wave height (see Figure 7-7 for definitions). Results 

 predicted by Figures 7-8 through 7-12 are probably smaller than the runup on 

 prototype structures because of the inability to scale roughness effects in 

 small-scale laboratory tests. Runup values from Figures 7-8 through 7-12 aan 

 he adjusted for scale effects by using Figure 7-13. 



Runup on impermeable structures having quarrystone slopes and runup on 

 vertical, stepped, curved and Galveston-type recurved seawalls have been 

 studied on laboratory-scale models by Saville (1955, 1956). The results are 



7-16 



