Lagoon are not stable. The effect of spring tide, 

 high waves, and direction of alongshore transport 

 of sand on the stability of the spits bordering Mugu 

 Lagoon is discussed. 



NO. 15 - January 1950 



II-C "Longshore - Bars and Longshore Troughs" by Dr. Francis P. 

 Shepard 



The submerged longshore-bars and longshore-troughs vrtiich 

 skirt the shores off most sandy beaches are described 

 and explained. The depths of the bars and troughs are 

 shown to be related to wave and breaker heights. Analysis 

 of hundreds of profiles taken mostly on the west coast 

 of the United States is the chief basis for conclusions 

 in the report. 



NO. 16 - May 1950 



II-* "Accretion of Beach Sand Behind a Detached Breakwater" by 

 C John W. Handin and John C. Ludwick 



The problem of sand transport by longshore current is 

 clarified by observing effects of the detached offshore 

 breakwater at Santa Monica, California. Correlation is 

 attempted between transporting pcwer of longshore forces, 

 median grain sizes of the beach sand, and the position of 

 the breakwater. 



NO. 17 - June 1950 



II-C "Test of Nourishment of the Shore by Offshore Deposition of 

 E Sand" by J. V. Hall, Jr. and W. J. Herron 



Field investigations to test the feasibility of nourish- 

 ing eroded shores with spoil from hopper dredges are 

 reported. Test included deposition, in 38 feet of water 

 about half a mile offshore from Long Branch, N. J., of 

 about 600,000 cubic yards of sand dredged in maintenance 

 of New York Harbor channels, and a study of its movement 

 by natural forces. 



NO. 18 - July 1950 



II-A "The Rayleigh Disk as a Wave Direction Indicator" by J. V. 

 Hall, Jr. 



The principles of operation of the Rayleigh Disk in stream 



82 



