shows the grain size distribution of sand.* The mean diameter of the 

 sand (dsn) was found to vary from 1.3 mm at Salmon Creek to 0.35 mm 

 halfway between Salmon Creek and Mussel Point. According to the grain 

 size variations and the alignment of the coastline in the area con- 

 sider.ed, the whole distance was divided into eight reaches (Figure 1). 

 Table 1** shows the characteristics of each reach. 



Transport Calculations. At this point, one should ask, what method 

 is to be used for calculating the transport? It is clear from previous 

 work(2,6) that the Bagnold formula seems to be superior to any other 

 formula for the following reasons: 



1. Bagnold's equation considers the grain-size diameter 

 (Equation l),and since we have a significant change 

 in d50 from reach to reach, the Bagnold formula seems 

 superior. 



2. The value of the coefficient C in the Bagnold formula 

 is better defined and more limited in range than the 

 coefficient K in the Kawamura formula. ^^^ 



3. The Kawamura formula (Equation 2) also includes the 

 threshold shear velocity which introduces a further 

 uncertainty in the calculations of transport rate, 

 especially since the factor is influenced by the 

 moisture content of the sand. ^^-^ 



4. The use of the O'Brien and Rindlaub formula is not 

 good here, since it has been shown that their equation 

 should be limited to sand having the same grain 

 diameter of that tested in the f ield, (^^(d ■ 0. 195 mm) 



Accordingly, the Bagnold formula will be used in the following calcula- 

 tions for sand transport. 



Equation (1) gives the transport in pounds per second per one-foot 

 length. Rewriting Equation (1) in a more general way 



d" 



q = C ■ I • T ■ J - 1 \]J (11) 



*Since the sand size of the reference point is a measure of the sand 

 being moved along the coast as littoral drift, it Is also the sand 

 that is moved back into the dune area by wind action. 



♦♦Tables at end of text. 



