PREFACE 



This report describes a proposed technique for predicting overtopping 

 rates for structures exposed to irregular wind-generated waves by extend- 

 ing the method of predicting overtopping for waves of constant height and 

 period presented in the Shore Protection Manual (SPM) (U.S. Army, Corps 

 of Engineers, Coastal Engineering Research Center, 1975). Results pro- 

 duced by the technique should be more representative of conditions in 

 nature than the SPM procedures. However, while the present SPM proce- 

 dure is based on laboratory tests, the proposed technique has not been 

 directly tested in the laboratory or the field. Therefore, results from 

 the technique should be used for general guidance until results of 

 laboratory tests presently underway become available. 



This report was prepared by John Ahrens , Oceanographer, under the 

 general supervision of Dr. R.M. Sorensen, Chief, Coastal Structures 

 Branch . 



The author acknowledges the extensive computer programing assistance 

 from M. Titus, and the useful suggestions by Dr. R.M. Sorensen. 



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. 



/JOHN H. COUSINS 

 Colonel, Corps of Engineers 

 Commander and Director 



