The simplest examples are those of beaches having negligible or identically 
constant bluff-berm, uniform beach slope, and uniform lake level. In these 
instances, the general equation (38) reduces to 
2 aK 
aa F(a) ieee oy 2Kp TES Ks GSN Cy 2 PGs) ee (40) 
ot : (C7, ) ox ox ox 
i+ ax 
subject to the appropriate boundary conditions. 
Suppose (as shown in Fig. 8) the beach is initially zero, bounded by a 
breakwater which is a complete littoral barrier, and subjected to waves having 
uniform positive deepwater direction. The boundary conditions are 
oy 
= 1S > TEIN Ou ke 0) 
OX 
e) 
avi Olay xd hls 
ax 
where L is a distance along ox, large enough so as not to be influenced by 
the groin. 
The shoreline is calculated for a fixed Hj, T, at intervals of equal At 
(shown in Fig. 8) for selected times. The general shape of these curves is 
Similar to the type formulations obtained by Pelnard-Considere (1956). 
INCOMING WAVE DIRECTION 
INCOMING WAVE DIRECTION 
INITIAL SHORELINE \ INITIAL SHORELINE 
Figure 8. Initial shoreline and incoming wave direction (A); 
shorelines at successive times of 1At, 2At, SAt, 
10At, and 20At (B) (vertical scale exaggerated). 
24 
