of removing other test models from the large wave tank for these beach 

 deformation tests, these tests were performed with a shorter tank length 

 than were the corresponding tests with the 0.2-mm sand. It was recognized 

 that this might introduce different reflection effects into development of 

 the comparative profiles, but it was felt that these effects would not be 

 large, particularly in the nearshore area of most interest. However, in 

 an attempt to secure additional information on such possible reflection 

 effects, the 0.2-mm tests which had been modeled using crushed coal are 

 being repeated with the shorter (model) tank length. Repetition will 

 enable comparison of test results with the coal for the two different 

 tank lengths. 



(h) Wave Measurements and Analysis 



Wave gage records were taken at all field gage locations until March 

 5 when gages at Palm Beach and Atlantic City were destroyed by the severe 

 east coast storm. Reinstallation is planned following rehabilitation 

 and reconstruction of the piers at these locations. A gage installation 

 at Virginia Beach, Virginia, is also planned in cooperation with local 

 elements. A new type bottom pressure gage will be installed at Atlantic 

 City, New Jersey, in addition to the normal staff gage. Comparison of the 

 records from these gages both by direct time comparison and by comparison 

 of the spectrum analyses, should bring about better knowledge of the wave 

 pressure attenuation with depth. Magnetic tape recorders to obtain tapes 

 for analysis on the spectrum analyzer have been installed with virtually 

 all gages. Additional tape recorded wave data have been obtained at many 

 of the field locations, and further spectral analyses made on the analyzer. 

 The actual shape of the height componentsat various selected periods in 

 the spectrum have been extracted for certain wave conditions, and analysis 

 thereof is underway. Further work with the magnetic tape analyzer has 

 enabled quantitative values to be assigned to the wave heights associated 

 with the various periods of the spectrum. A program for testing feasibility 

 of using two staff resistance wave gages (relay type) for determining wave 

 direction was carried out in the large wave tank, but preliminary results 

 indicate that while the method worked fairly satisfactorily for long period 

 waves, considerable difficulties ensue with short period waves. 



(i) Regional Studies. 



A report "Littoral Materials of the South Shore of Long Island, New 

 York" has been published as Technical Memorandum No. 129 of the Beach 

 Erosion Board. This report describes the physical characteristics of 

 littoral materials along the south shore of Long Island, tabulating median 

 diameter, and sorting and skewness coefficients for beach and bottom sedi- 

 ments for comparable zones of the profile and comparable survey periods 

 at all locations where such data are available. In addition, a limited 

 amount of data on physical properties such as mineral composition, round- 

 ness and sphericity of grains, specific gravity, and mass density are also 

 presented. Additional compilations are underway on geomorphological and 



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