APPENDIX C 



FIELD AND LABORATORY DATA IN THE SPM ENERGY FLUX DISCUSSION 



Figure 4-36 in the SPM is a plot of longshore transport rate, Q, versus 

 longshore energy flux factor, ^is' ^'^^ both field and laboratory data. A 

 similar plot of Q versus P^g (Fig. 4-37 of the SPM) presents only the field 

 data. The empirical relation, 



Q 



(7.5 X 103) P 



£s 



(C-1) 



where Q is measured in cubic yards per year and P^g is measured in foot- 

 pounds per second per foot of beach front, is a visual fit of the field data 

 in Figure 4-37. It is given as equation (4-40) in the SPM. 



The field data are taken from Watts (1953), Caldwell (1956), Moore and Cole 

 (1960), and Komar (1969). The laboratory data are taken from Krumbein (1944), 

 Saville (1950), Shay and Johnson (1951), Sauvage and Vincent (1954), and 

 Fairchild (1970) . These data are described and listed in Das (1971) and the 

 derivation of empirical relations of the form of equation (C-1) is summarized 

 in Das (1972) . 



The field data include 25 data points, although only 23 of them are shown 

 on Figure 4-37 of the SPM. Four data points come from Watts (1953) . The long- 

 shore transport rate, Q, was measured by surveying the amount of sand pumped 

 into a detention basin by a bypassing plant on the jetty at south Lake Worth 

 inlet in Florida. Surveys were made after every 6 hours of pumping or daily, 

 whichever was more often. Four monthly totals are used. The equivalent long- 



shore energy flux factor, 

 from linear theory 



Is 



(denoted as Ej> in Watts' paper), was computed 



Is 



= - LH^ 



1 - 



nr 



t . 



T 



(C-2) 



where 



w = weight density of seawater 



L = wavelength 



H = wave height 



M = a function of d/L where d is the water depth 



T = wave period 



a = the angle between the wave crests and the shoreline 



t = conversion of seconds to days 



n = solution given by equation (2.68) of Wiegel (1964), 



1 



1 + 



477 



sinh 



m 



(C-3) 



30 



