1 . In addition to determining overtopping coefficients from the Roughans 

 Point laboratory tests, some additional coefficients were derived from a 

 previous study for use in estimated overtopping rates for the existing north 

 wall at Roughans Point. The previous study was conducted by Saville (1955)* 

 using monochromatic wave conditions on a variety of seawall configurations. 

 While the degree of comparability between monochromatic and irregular wave 

 overtopping tests is not fully understood, the coefficients determined from 

 the earlier monochromatic tests were applied to existing seawall configu- 

 rations for sheltered locations on Broad Sound (Reaches A through D, Figure 2, 

 main text). Note that the monochromatic coefficients should not be used for 

 locations exposed to the open coast. Monochromatic data trends were also 

 similar to the irregular wave overtopping data trends, and the monochromatic 

 coefficients exhibited logical tendencies. A for example, as shown in Table 

 B1, is a measure of the amount of overtopping and tends to increase with 

 increasing water depth, which is what logically should happen. 



Table B1 



Overtopping Coefficients for Saville 's 



Monochromatic Data 



Overtopping Coefficients 



Structure 

 Configuration 



Vertical wall 



Riprap 1 on 1.5 



Water 



Q 



C.F' 

 = Qe 





Configuration 

 Overtopping 



Depth 

 d s , ft 



Q , ft 2 / 



3.47 



3.82 



10.58 



sec 



C 1 



Rating 

 A q 



0.0 

 4.5 

 9.5 



-10.074 

 -5.762 

 -6.776 



0.0168 

 0.1177 

 0.2045 



0.0 

 4.5 

 9.0 



6.88 



8.66 



18.86 





-11.434 

 -9.751 

 -9.762 



0.0195 

 0.0476 

 0.1033 



* The range of F' is from 0.094 to 1.277. 

 ** See paragraph 17. 



References cited in this appendix are included in the References at the end 

 of the main text. 



B2 



