0.5 1 1.5 



ALONGSHORE DISTANCE (x/y ) 



Figure 9. Shoreline evolution when sand is supplied at x = 



to maintain a specific beach width y 

 r o 



diffraction and refraction, but this realistic situation is not described by 

 the linearized equation. Consequently, the linearization procedure artifi- 

 cially increases the erosion of the fill, implying that the analytical solu- 

 tion overestimates the speed of erosion. The error is, therefore, on the con- 

 servative side. This problem is only an apparent one since it is a practical 

 impossibility to create a perfectly rectangular fill in the field. 



Semi-Infinite Rectangular Beach Fill 



38, 



The initial conditions for a semi-infinite rectangular beach fill 



y(x,0) = 



x < 

 x > 



(28) 



Walton and Chiu (1979) give the following solution: 



23 



