a. Determine the direction and rate of littoral drift; 



b* Determine whether or not a reduction in the rate of littoral 

 drift over the area would result in damage to downdrift areas. The amount 

 of this damage must be considered in determining the economic justification 

 for the project; 



c» Construct the first breakwater at or near the downdrift end 

 of the area to be protected. It should be short and an adequate distance 

 from shore; 



d. Observe the action of this structure and when the shore 

 line has reached an apparent stability, construct the second breakwater 

 at the point farthest updrift from the first structure that any accretion 

 is apparent; 



e. Repeat the process until the entire reach has been protected, 



192. An offshore breakwater will have the same effect on the shore 

 line if it is not parallel to shore as it would have if it were parallel 

 to shore, except that the effective length of the structure will be re- 

 duced to the projection of the structure normal to the resultant direction 

 of wave propagation. See Figure 73. 



Shore line- 



/ 



/ 

 Of #A ''I'e u 



Breakwater 



FIGURE 73. EFFECTIVE LENGTH OF AN OFFSHORE BREAKWATER 



98 



