lated conditions for shore structures and incident 

 and reflected wave heights measured. Empirical re- 

 lations are determined between the amount of energy 

 absorbed for permeable and impermeable faces and such 

 variables as thickness of structure, rock diameter, 

 void percentage, and slope of seaward face. 



NO. 12 - February 1952 



II-E "Durability of Steel Sheet Piling in Shore Structures'* by 

 A. C. Rayner and Culbertson W. Ross 



153 groups of steel sheet piling structures along the 

 Atlantic Coast of the United States and the Gulf coast 

 of Florida were studied and classified. Structures were 

 selected for various conditions of exposure and treat- 

 ment and types. Measurements and observations were made 

 over a 10 year period and general conclusions presented 

 regarding useful life of steel sheet piling. Measured 

 and observed data are tabulated and appended to the 

 report. 



NO. 13 - January 1950 



U-C "Longshore Current Observations in Southern California" by 



Dr. Francis P. Shepard 



Currents were measured in the surf zone at frequent inter* 

 vals throughout a year along the Southern California 

 coast. Study shows the dominant currents in the area 

 from the Mexican Border to Newport to be to the south. 

 North currents prevail during a large part of the summer 

 and fall. Strong alongshore currents exist even during 

 times when large waves approach from directions essen- 

 tially normal to the beaches. Importance of currents 

 moving along the shore away from points of wave con- 

 vergence is demonstrated. 



NO. 14 - March 1950 



II-C "Report on Beach Study in the Vicinity of Mugu Lagoon, 

 California" by D. L. Inman 



An investigation to determine the relative stability of 

 the beaches and sand spits in the vicinity of Point Mugu 

 and to make recommendations for their preservation. 

 Investigations shew beaches and sand spits bordering Mugu 



81 



