PREFACE 
This report presents guidelines for interpreting nondirectional wave energy 
spectra. The guidelines apply to spectra derived from both wave gage measure- 
ments and from numerical wave hindcasting models. A method is provided for 
using the spectrum to estimate a significant height and period for each major 
wave train in a sea state, except major wave trains with nearly the same period 
and different directions cannot be distinguished. The method has undergone 
limited testing and has been applied to 7 station-years of gage data, but fur- 
ther testing in well-documented field situations is needed. The guidelines and 
method are consistent with but are more practical and explicit than the material 
in the Shore Protection Manual (SPM). The work was done under the wave measure- 
ment program of the U.S. Army Coastal Engineering Research Center (CERC). 
This report was prepared by Edward F. Thompson, Hydraulic Engineer, under 
the general supervision of Dr. C.L. Vincent, Chief, Coastal Oceanography Branch. 
Helpful reviews by Dr. C.L. Vincent, Dr. D.L. Harris, P. Knutson, and P. Vitale 
are acknowledged. Dr. D. Esteva provided the data for Figure 6. 
Comments on this publication are invited. 
Approved for publication in accordance with Public Law 1966, 79th Congress, 
approved 31 July 1945, as supplemented by Public Law 1972, 88th Congress, 
approved 7 November 1963. 
Colonel, Corps of Engineers 
Commander and Director 
