TECHNICAL MEMORANEA 



NO. 106 - August 1958 



' Laboratory Study of Breaking Wave Forces on Piles " by 

 M. A. Hall 



Model studies were performed at the University of 

 California to investigate the forces of breaking 

 waves on piles located on a sloping beach. A 

 suitable dynamometer was developed and measurements 

 were made for a number of different wave conditions 

 on a single beach slope (1:10) and for two different 

 pile diameters. The resulting maximum forces are 

 presented in dimensionless form for convenience. 



NO. 107 - August 1958 



"Behavior of Beach Fill and Borrow Area at Harrison 

 County. Mississippi " by G. M. Watts 



Survey and sand sample data were analyzed to de- 

 termine the behavior of beach fill placed along 

 25 miles of shore in 1951 from an offshore borrow 

 source. Material losses since placement have been 

 slight, amounting to less than 0.1 cubic yard per 

 year per linear foot of shore. The stability of 

 the beach fill and relatively slow offshore slope 

 adjustment demonstrates the suitability of original 

 fill material. Shoaling of the borrow area has 

 been slow and limited to material of silt size. 



NO. 108 - November 1958 



' Surf Statistics for the Coasts of the United States " 

 by James R. Helle 



Visual observations of surf conditions such as period, 

 significant height and direction were begun in 1954 at 

 27 stations located on the Atlantic, Gulf and Pacific 

 coasts of the U. S., under a cooperative surf observa- 

 tion program between the U. S. Coast Guard and the 

 Beach Erosion Board. Data on surf heights occurring 

 for the 3-year period 1954-1957 are summarized on 

 a monthly basis in tabular form, and are presented 

 graphically as cumulative frequency curves on an annual 

 basis for each station. Effects of hurricanes on surf 

 conditions along the Atlantic and Gulf coasts were also 

 studied. A comparison of observed surf and hindcast 

 wave statistics is presented for the station at Grand 

 Isle, Louisiana. 



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