"o.Ol ^ ^0.01 

 H R 



Ln 0.01 



1/2 



= 1.52 



and 



R^ „, = 1.52 R = 1.52 (5.6) = 8.5 m (27.9 ft) 

 0.01 s 



(b) With R = 5.6 m and R = 7.5 m and if Figure 7-23 is used for 

 ^ ^ s p 



^ = 14= 1.34 



R 5.6 

 s 



then p = 0.028 or 3 percent of the runup exceeds the crest of the 

 structure. 



*************************************** 

 2. Wave Overtopping . 



^* Regu l ar (Monochromatic) Wav es. It may be too costly to design 

 structures to preclude overtopping by the largest waves of a wave spectrum. 

 If the structure is a levee or dike, the required capacity of pumping 

 facilities to dewater a shoreward area will depend on the rate of wave 

 overtopping and water contributed by local rains and stream inflow. Incident 

 wave height and period are important factors, as are wind speed and direction 

 with respect to the structure axis. The volume rate of wave overtopping 

 depends on structure height, water depth at the structure toe, structure 

 slope, and whether the slope face is smooth, stepped, or riprapped. Saville 

 and Caldwell ( 1953) and Saville ( 1955) investigated overtopping rates and 

 runup heights on small-scale laboratory models of structures. Larger scale 

 model tests have also been conducted for Lake Okeechobee levee section 

 (Saville, 1958b). A reanalysis of Saville' s data indicates that the 

 overtopping rate per unit length of structure can be expressed by 



Q = 



* .3 



1/2 



ofZ ..- ^^ 



(7-10) 



in which 







h - d 



< 1.0 



or equivalently by 

 Q 



= (« % "f )' 



0.1085 



log 



R+h-d 



s 



e \ R-h+d 



s> 



(7-11) 



in which 



h - d 



e 



R 



< 1.0 



7-43 



