rate is obtained from profile surveys separated by several hours, the inshore 

 peak of the distribution was sometimes not clear. Also, the number of cases 

 studied in which wave reformation occurred was limited. This made information 

 scarce about the net transport rate in zones of wave reformation, and choice 

 of the shape of the transport rate distribution became somewhat arbitrary. 



475. It is reasonable to assume that the transport rate in zones of 

 wave reformation is a function of the transport characteristics in the 

 bordering zone of broken waves, since mobilization and transport are expected 

 to be most intense in the broken wave zone. It is therefore assumed that the 

 magnitude of the transport rate at the boundary of the broken wave zone 

 determines the magnitude of the transport rate in the wave reformation zone. 

 Then, only information about the functional form of the decay of the transport 

 rate to the point of minimum transport and the location of this minimum are 

 required to completely specify the transport rate distribution in the wave 

 reformation zone. The magnitude of the minimum transport rate in the wave 

 reformation zone is given by a decay function once the location of the minimum 

 is specified. 



476. Various trial functions were investigated to find a suitable 

 description of the transport rate distribution in the wave reformation zone, 

 focusing on exponential and power functions. A qualitatively acceptable 

 representation of beach profile evolution was obtained by an exponential decay 

 from the point of wave reformation shoreward to the point of minimum trans- 

 port. From the second break point seaward to the point of minimum transport, 



a power law was applied to describe the transport rate. By introduction of 

 these empirical functions, additional parameters are introduced in the model, 

 and their magnitudes must be determined through calibration against measure- 

 ment. The two empirical transport relationships used to describe the trans- 

 port rate q in zones of wave reformation are 



q = qr e 



-iy(Xr-x) 



Xm ^ X < X^ 



(47) 



and 



q = qb + (qm - qb) 



^ - ^b 



Xb < X < x^ 



(48) 



200 



