CURVE 



1.0 

 2.0 

 3.3 

 6.0 

 10.0 



Figure 16 . Five examples of JONSWAP spectra in dimen- 

 sionless form (Case (a) is a Pierson-Moskowitz spec- 

 trum; Case (c) is the result of the JONSWAP 

 experiment) 



values were substituted for H D in Equation 1, and respective stability 

 numbers are presented in Table 7. These stability numbers were cubed and are 

 plotted against relative berm depth (Figure 17). To make comparison easier, 

 the stability data for all 2-D and 3-D monochromatic wave toe berm tests were 

 added to the plot. The spectral data show the same trend, but the use of H^ 

 in Equation 1 results in lower stability numbers. The use of H^ in 

 Equation 1 does not show that the spectral wave conditions were more severe 

 than the monochromatic breaking waves but instead points out that the magni- 

 tude of H mo is smaller than the monochromatic breaking wave heights that 

 were measured at the toe of the structures for the same incident wave period 

 and water depth. Thus, when H^ is substituted for H D in Equation 1 the 

 resulting stability number is smaller than those calculated using the breaking 

 wave height. 



30. The limited spectral toe berm stability tests described herein are 

 by no means intended to represent extensive enough parameters from which 



28 



