the land to be protected. It must certainly cover the low spit area and 
extend to a point where some shore recession can be tolerated between sand 
bypassing or groin filling operations. The groin field should be of the 
low profile type. In the event that a beach is not necessary for recrea- 
tional purposes in the area, the bulkhead and groins may be replaced with 
a substantial seawall, preferably a rubble mound to reduce wave run-up and 
overtopping. In the event that large rock is not available in the area, 
concrete shapes, tetrapods, quadripods or others may be used, 
Structural design today is a straightforward process. Having selected 
a design wave (usually defined as the average of the highest one-third 
of the waves in the spectrum), together with a design tide (taken as the 
astronomical tide plus selected storm surge), construction material charac- 
teristics and foundation conditions, the final design becomes a matter of 
adjusting natural forces to man's need, with recognition that these forces 
are to be controlled by structures compatible with the natural situation. 
SELECTED REFERENCES 
Beach Erosion Board, U.S. Army Corps of Engineers, 1961, "Shore Protection 
Planning and Design", Technical Report No. 4 (available from Super- 
intendent of Documents, U.S. Government Printing Office, Washington 
2 DEC Ep IICemss KOO) Ee 
Krumbein, W. C., 1963. "A Geological Process-Response Model for Analysis 
of Beach Phenomena'' : Paper presented before ASCE Water Resources 
Engineering Conference, Milwaukee, Wisconsin, 15 May 1963. 
SiG 
