NO. 81 - June 1956 



I-A "A Laboratory Study of Short-Crested Wind Waves" by 



G. C. Ralls, Jr., and R. L. Wiegel 



Results are presented from a three-dimensional study 

 of fundamental characteristics of short -crested waves 

 in a laboratory wind-wave tunnel. General charac- 

 teristics of the waves are shown for varying wind 

 speeds, water depths, and fetch lengths. Several 

 methods of analyzing short -crested waves to obtain 

 quantitative data on wave parameters are discussed, 

 and the results of the methods compared. It was 

 found that the crest length as well as the wave 

 length could be described by a Gaussian distribution. 



NO. 82 - July 1956 



II-B *K:;hanges in Sand Level on the Beach and Shelf at La Jolla , 



C California" by D. L. Inman and G. S. Rusnak 



D 



A technique is developed for establishing a reference 

 level on the bottom from which small net changes in 

 sand level can be measured by swimmers equipped with 

 self-contained underwater breathing apparatus. Bottom 

 changes were measured periodically over a 3-year interval 

 at stations from near the surf zone to the 70-foot depth. 

 Standard error of the measurements was about + 0.05 

 foot per survey for determination of net sand level. 

 Estimates of sand level variation are made for monthly 

 and seasonal periods and correlated with depth. Com- 

 parison is also made with sonic (echo) soundings, 

 indicating day-to-day accuracy for the latter method 

 on the order of + 0.5 foot. 



NO. 83 - June 1956 



II-C "Approximate Response of Water Level on a Sloping Shelf 

 F to a Wind Fetch Which Moves Towards Shore" by R. O. Reid 



A procedure for evaluating the approximate response 

 characteristics of water level at the shore of a sloping 

 shelf due to a wind fetch moving directly onshore is 

 described. The theory is based upon the linear one- 

 dimensional wave equation and employs the method of 

 characteristics as a means of solution by graphical 

 technique. A total of about 55 separate cases for 



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