BACK SHORE 



CREST OF BERM-% 



~^^ 



/ PATH OF BEACH DRIFT 



/ I 

 / I 



>r- STILL WATER LINE 



DIRECTION OF WAVE INDUCED 



CURRENT IN THE SURF ZONE ,^ 



Z ^. 



MATERIAL PLACED IN SUSPENSION BY BREAKERS IS 

 MOVED LATERALLY BY THE LONGSHORE CURRENT, AS 

 WELL AS LATERALLY AND IN A ZIGZAG PATTERN 

 ALONG THE BED. 



BED LOAD MOVES UP OR DOWN COAST IN A ZIGZAG 

 PATTERN. MOVEMENT IN ALL THREE ZONES ILLUSTRATED 

 IS IN A DIRECTION AND AT A RATE DEPENDENT ON THE 

 LONGSHORE COMPONENT OF WAVE ENERGY. 



Fig. 35 LATERAL MOVEMENT OF LITTORAL DRIFT 



o.oe 0.03 



Wave Steepness 



Ho/Lc 



0.05 



0.06 



Fig. 36 



LABORATORY RESULTS INDICATING TRENDS OF PROPORTIONATE 

 BED LOAD AND SUSPENDED LOAD TRANSPORT RELATED TO 

 WAVE ENERGY AND WAVE STEEPNESS. (SAVILLE 1950) 



46 



