Elapsed Time (hr) 



Figure 41. Evolution of peak onshore net sand transport rate 

 for 16 CE cases 



332. The average temporal rate coefficient in Equation 20 was a = 

 1.42 hr'-^ for the studied cases, with standard deviation of 2.50 hr"^. Thus, 

 decay in the peak onshore transport rate was more rapid than for the peak 

 offshore rate. This finding is in agreement with observations made by 

 Sawaragi and Deguchi (1981) from laboratory experiments in which they noted 

 that the onshore transport decayed faster with time than the offshore trans- 

 port. It is hypothesized here that the peak onshore transport rate decays 

 more rapidly than the peak offshore rate because of the retarding force of 

 gravity on onshore sand motion on a sloping beach. 



333. Also, in the present case, there is a wider range in values of the 

 rate coefficient for the peak onshore transport rate compared to the peak 

 offshore rate, as illustrated by the larger standard deviation. The rate 

 coefficient showed a lower correlation with wave period (r = 0.50) than did 

 that for offshore transport but still a rather high correlation with the 

 initial peak onshore transport rate (r = 0.75). No significant correlation of 

 peak onshore rate with wave or sand parameters was found. 



135 



