Reprint or republication of any of tliis material shall give appropriate 

 credit to the U.S. Army Coastal Engineering Research Center. 



Limited free distribution within the United States of single copies of 

 this publication has been made by tliis Center. Additional copies are 

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 A TTN: Operations Division 

 5285 Port Royal Road 

 Springfield, Virginia 22151 



Contents of tliis report are not to be used for advertising, 

 publication, or promotional purposes. Citation of trade names does not 

 constitute an official endorsement or approval of the use of such 

 commercial products. 



The findings in tiiis report are not to be construed as an official 

 Department of the Army position unless so designated by other 

 authorized documents. 



