fine sands would actually form a beach under laboratory conditions. 

 Because of the economy of time in setting up such experiments and be- 

 cause of the flexibility permitted in varying the experimental conditions, 

 a series of experiments were made in the one-foot wave channel located 

 in the Fluid Mechanics Laboratory of the University of California (for 

 complete details see the report Issue NO, 5 S Series 14, as listed in , 

 Part vT)<> The purposes of this investigation were; 



a„ To study the action of waves on beaches where no littoral sand 

 transport occurs; comparing the profiles formed by normal waves (0° 

 angle) for various selected wave -steepness ratios. 



bo To observe the movement of beach sand under the action of 

 waves perpendicular to the beach with and without tides, 



c. To determine whether very fine grained sands will make a beach 

 or what minimum grain sizes could be used for forming a model beach 

 under existing experimental conditions, 



d e To determine the amount of material in suspension due to wave 

 action on these fine sands, and the particle -size distribution through- 

 out the channel bed, 



e„ To show the formation of a beach starting from an initially 

 uniform slope to its final stable condition. Further, to show how a 

 beach (where no littoral transport occurs) changes shape when the period 

 is suddenly varied. 



Summary 



The movement of waves impinging upon the sand beach and the subsequent 

 movement of the sand particles were observed through a glass-walled 

 wave channel. After each beach tested had reached a stable condition, 

 the lengths of the foreshore beach and the berm height were measured . 

 Both of these values, for a given sand and a given wave steepness, were 

 found to be directly proportional to the square of the wave period. 

 More experimental data are required to establish a relationship be- 

 tween the berm height and the foreshore slope to both the steepness 

 ratio and the grain diameter. 



Observation showed that receding tides tend to flatten or smooth 

 out the entire beach profile while a rising tide keeps the original 

 beach profile intact but moves the beach position landward. 



It was found that only the sand mixtures having a grain-size dis- 

 tribution curve similar to the natural beach sands resulted in the for- 

 mation of a stable model beach. Furthermore, in contrast to this, it 

 was found that if a sand mixture was used that had a relatively wider 

 range of the grain sizes than that occurring in natural beach sands, 

 the particles tended to segregate. This resulted in the beach becomirjjg 



