Runup Distance (m) 



Figure 28. Relation between berm center of mass and wave runup 



286. For most berms , the horizontal movement of their center of mass 

 was small, indicating that the berm grew uniformly in time over its length. 

 If the berm showed a net movement of its center of mass, it was always in the 

 shoreward direction. The length of the berm at equilibrium appeared to depend 

 mainly on breaking wave height and little on wave period (Bagnold 1940, 

 Sunamura 1975, Takeda 1984). 



Active profile height 



287. A quantity Zr was defined as the maximiom subaerial elevation of 

 the active profile above still -water level for either bar or berm profiles 

 (Figure 4b). An empirical equation was obtained from the LWT data by relating 

 this quantity to the surf similarity parameter, tau^/iti^/h^)^'^ (Battjes 1975). 

 The surf similarity parameter was evaluated using the initial beach slope, 

 resulting in the empirical equation 



108 



