T.M. No. 52 - December 1954 



Laboratory Study of Effect of Tidal Action on Wave-Formed Beach 

 Prof i I es by George M. Watts and Robert F. Dearduff 



Some two-dimensional tests to study equilibrium profiles of 

 beaches previously made in a laboratory wave tank utilizing uniform 

 wave trains were repeated, introducing a tidal system and resulting 

 profiles compared. Results indicate that introduction of tidal 

 action causes no appreciable changes in foreshore and offshore 

 slopes, but movement of material throughout the profile increases 

 in proportion to the tidal range, creating higher beach berms and 

 recession of the shoreline. Formation of offshore bars and troughs 

 inherent in the non-tidal tests due to wave reflections was 

 inhibited by introduction of the tidal system. 



T.H. No. 55 - September 1954 



Laboratory Study of Effect of Varying Wave Periods on Beach Profiles 

 by George M. Watts 



Tests were made in a laboratory wave tank to determine desirable 

 magnitude and frequency of variation in wave periods in tank tests 

 in order to eliminate irregularities in resulting beach profiles 

 accentuated by use of a constant fixed period, and thereby, more 

 nearly approximate the profiles resulting in nature from wave trains 

 with a variety of components. Profiles resulting from these tests 

 were compared with those from similar tests utilizing constant wave 

 periods, and foreshore and offshore slopes were found to be essen- 

 tially identical. In general, the variable-period tests resulted 

 in less material movement from the same test time. Offshore bar 

 and trough formations inherent in constant period test were greatly 

 reduced by varying the wave period. 



T.M. No. 54 - November 1954 



Laboratory and Field Tests of Sounding Leads by George M. Watts 



Results of tests to determine the relationship between various 

 sizes, shapes and weights of sounding leads, and the degree of 

 penetration of the leads into bottom materials of various physical 

 properties are presented. Tests were made both in the I a bora ry and 

 field. The field data were compared with echo soundings. Of the 

 leads tested, the spherica I -shaped lead demonstrated characteristics 

 more nearly approaching those needed for a "practical" shaped 

 sounding lead. 



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