'Point of maximum wave runup 



Figure 7-7. Definition sketch: wave runup and overtopping. 



shown in Figures 7-14 through 7-18. Effects of using graded riprap on the 

 face of an impermeable structure (as opposed to quarrystone of uniform site 

 for which Figure 7-15 was obtained) are presented in Figure 7-19 for a 1 on 2 

 graded riprap slope. Wave rundown for the same slope is also presented in 



Figure 7-19. Runup on pevmeahle vuhhle slopes as a function of structure 



2 

 slope and H'/gT is compared with runup on smooth slopes in Figure 7-20. 



Corrections for scale effects, using the curves in Figure 7-13, should be 

 applied to runup values obtained from Figures 7-8 through 7-12 and 7-14 

 through 7-18. The values of runup obtained from Figure 7-19 and 7-20 are 

 assumed directly applicable to prototype structures without correction for 

 scale effects. 



As previously discussed. Figures 7-8 through 7-20 provide design curves 

 for smooth and rough slopes, as well as various wall configurations. As 

 noted, there are considerable data on smooth slopes for a wide range of d /H' 

 values, whereas the rough-slope data are limited to values of d /H' > 3 . It 

 is frequently necessary to determine the wave runup on permeable rubble 

 structures for specific conditions for which model tests have not been 

 conducted, such as breaking waves for d /H' < 3 . To provide the necessary 



design guidance, Battjes (1974), Ahrens (1977a), and Stoa (1978) have sug- 

 gested the use of a roughness and porosity correction factor that allows the 

 use of various smooth-slope design curves for application to other structure 

 slope characteristics. This roughness and porosity correction factor, r , 

 is the ratio of runup or relative runup on rough permeable or other nonsmooth 

 slope to the runup or relative runup on a smooth impermeable slope. This is 

 expressed by the following equation: 



7-18 



