PREFACE 



This report provides a calculation procedure for the threshold of sand 

 motion by wave action, and thus, an ultimate seaward limit to wave effects on 

 a sand bottom. The present treatment replaces guidance on initiation of sedi- 

 ment motion furnished in Section 4.522 of the Shore Protection Manual. The 

 work was carried out under the beach behavior and restoration research program 

 of the U.S. Army Coastal Engineering Research Center (CERC) . 



This report was written by Dr. Robert J. Hallermeier, Oceanographer , under 

 the general supervision of Dr. R.M. Sorensen, Chief, Coastal Processes and 

 Structures Branch, Research Division. 



Comments on this publication are invited . 



Approved for publication in accordance with Public Law 166, 79th Congress j 

 approved 31 July 1945, as supplemented by Public Law 172, 88th Congress, 

 approved 7 November 1963. 



TED E. BISHOP 



Colonel, Corps of Engineers 



Commander and Director 



