in which R 2 is 2-percent runup; the elevation exceeded by 2 percent of the 

 total wave runup, R s is the significant runup; the average of the highest 

 one-third of all runup, and R is the average runup. The surf similarity 

 parameter was determined using H s and peak deepwater wavelength (Lp) , 

 calculated using the peak period T p in Equation 1. Significant wave height 

 was measured at the toe of the structures. 



78. Mase and Iwagaki (1985) conducted laboratory experiments to esti- 

 mate runup on plane slopes of 1/5, 1/10, 1/20, and 1/30 with irregular waves 

 that simulated a Pierson-Moskowitz spectrum. From the experimental results, 

 the following equations were found: 



(H.)o 



= a(tan 0) 1 



(H s ) 



I (Ls)o J 



(56) 



(H s ) 



= d(tan y9) 



(H s )o 



(L s ) 



(57) 



in which (L s ) is the significant deepwater wavelength, calculated using the 

 significant period T s in Equation 1, and the parameters a through e 

 varied depending on whether R , R,,,^ , or R s was predicted. 

 Summary 



79. The parameters used to determine runup on smooth plane slopes are 

 beach slope and wave steepness. Factors that influence runup in nature also 

 include the roughness and porosity of the slope, and corrections to the above 

 equations must be made to account for the effect of these quantities . 



Analysis of Previous Data 



80. In the present study, selected data sets were reanalyzed to deter- 

 mine relationships for breaking wave height and plunge distance as a function 

 of beach slope and deepwater wave steepness on plane sloping beaches. The 

 following criteria were established to select data for this analysis: 



a. The study was conducted on a fixed plane slope with 

 monochromatic waves . 



42 



