Another ^^ery important set of constants is the constant chosen for the 

 longshore and cross-shore components of sediment transport. Equation (27), 

 the total longshore transport equation, contains the constant C equal to 



C = ^^^-^^ rn (A-2) 



(p^ - p) (1 - p) (16) (k)^'''^ 



where K = 0.77 (Komar and Inman, 1970) 



g is the acceleration of gravity (32.17 ft/sec^) 



Ps and p are the mass densities of the sediment 

 and the seawater (5.14 and 1.99 slugs per cubic feet, 

 respectively 



p is the porosity (0.40), and 



^ is taken as 0.78. 



Using these values to compute C (TKSI in the program), a value of 0.325 is 

 obtained. It is stressed that if any of these values are different for the 

 site to be modeled, they should be changed and the program will compute 

 another value for C' . 



The parameter Cqff "is an "activity factor" which, based on earlier work 

 primarily within the surf zone, was found to be 



Cqpp = lO"'^ ft/s, ^ < \ 



To generalize this concept for transport seaward of the surf zone, the 

 wave energy dissipation per unit volume was utilized as a measure of 

 mobilization of the bottom sediment. Inside the surf zone, the dominant wave 

 energy dissipation is caused by wave breaking; outside the surf zone, the 

 dominant mode of wave energy dissipation is due to bottom friction. These 

 two components will be denoted by Dj and D2, respectively. 



(a) Energy Dissipation by Wave Breaking . The wave energy dissipation 

 per unit volume by wave breaking, Dj, is ~ 



D^ = ^ ^ (E C3) (A-3) 



which, employing the spilling breaker assumption (H = ^h) within the surf 

 zone, can be shown to be 



57 



