T.M. No. 104 (Continued) 



on smooth and roughened surfaces of different slope under several 

 conditions of equivalent deepwater wave steepness. Theoretical 

 analysis is presented yielding an equation for net onshore-offshore 

 velocity of a given spherical sediment particle. The equation is 

 verified by laboratory measurements and extended. 



T.M. No. 105 - March 1958 



Movement of Bottom Sediment in Coastal Waters by Currents and Waves ; 

 Measurements with the Aid of Radioactive Tracers in The Netherlands 

 by J . J. Arlman, P. Santema, and J. N. Svasek 



Sediment movement by currents and waves and ordinary methods 

 of measurement are discussed. Procedures for marking and following 

 movement of bottom sediments by radioactive tracers are also dis- 

 cussed, and characteristics of a number of suitable radioactive 

 isotopes are tabulated. Pilot experiments to investigate tracing 

 of sediment movement by use of radioactive tracers are described and 

 it is concluded such a method can be safely employed by ordinary 

 field survey parties. However, manufacture and placement of the 

 radioactive material must be supervised by experts, after which 

 brief safety control is sufficient. 



T.M. No. 106 - August 1958 



Laboratory Study of Breaking Wave Forces on Piles by M. A. Ha I I 



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 measure- 

 ments 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 d imension I ess form for 

 convenience. 



T.M. No. 107 - August 1958 



Behavior of Beach Fil I and Borrow Area at Harrison County, 

 Missi ssipp i by George M. Watts 



Survey and sand-sample data were analyzed to determine the be- 

 havior 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 demonstrate the suitability of original 

 fill material. Shoaling of the borrow area has been slow and 

 limited to material of silt size. 



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