PREFACE 



This report is published to provide coastal engineers with detailed 

 explanations of three frequently asked questions concerning the energy flux 

 method described in Section 4.532 of the Shore Protection Manual (SPM) . The 

 questions involve the derivaton of equations for the energy flux factor, 

 the use of significant wave height in these equations, and the data used to 

 relate energy flux factors to longshore transport rate. These questions 

 require more elaborate explanations than is possible in the SPM. The work 

 was carried out under the coastal processes research program of the U.S. Army, 

 Coastal Engineering Research Center (CERC) . 



The report was written by Dr. Cyril Galvin, formerly Chief, Coastal 

 Processes Branch, and Charles R. Schweppe, formerly a student trainee in 

 Coastal Processes Branch, under the general supervision of R.P. Savage, Chief, 

 Research Division, CERC. The authors wish to thank CM. McClennan for advice 

 on the derivation, D.L. Harris for help with the significant wave height, 

 T.L. Walton for pointing out the importance of the breaker speed estimate, and 

 P. Vitale, principal investigator of the longshore transport prediction work 

 unit. 



Comments on this publication are invited. 



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

 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 



