PREFACE 



CERC is publishing this report because of its interest and value to coastal engineers. 



This report was prepared by J. W. Johnson, Hydraulic Engineering Laboratory, College of 

 Engineering, University of California, Berkeley. Work was completed during the author's 

 sabbatical-leave studies in the fall and winter tpaarters, 1972-73. 



NOTE: Comments on this publication are invited. 



Approved for publication in accordance with Public Law 166, 79" 1 Congress, approved 

 31 July 1954, as supplemented by Public Law 172, 88*" Congress, approved 7 November 

 1963. 



JAMES L. TRAYI 



Colonel, Corps of wfgineers 

 Commander and Director 



