guidelines towards the final design. Rosati and Truitt (1990) discuss the JMC 

 method of breakwater design and present several example problems. 



42. However, the JMC method has its disadvantages for use in design of 

 US detached breakwater systems. Approximately 60 percent of the projects on 

 which the method is based resulted in tombolo formation; therefore, it is more 

 appropriate for headland or pocket beach- type systems, rather than detached 

 breakwater or reef systems. Unlike US breakwater projects, beach fill is not 

 placed as a part of the JMC's projects; therefore, there is no provision for 

 beach fill in the iterative method. All structures considered in the JMC 

 study were permeable; however, the effect of increased or decreased structure 

 transmissibility is not included in the JMC method. For construction of a 

 highly transmissible structure such as a reef breakwater or perched beach, use 

 of the JMC method for design is most likely inappropriate. The wave height 

 required for input is the average of the highest five nonstorm waves that 

 occur in a typical year and corresponding wave period, often difficult 

 parameters to extract from typically available hindcast wave data sets. The 

 effects of a variable water level on design are not explicitly accounted for 

 in the procedure . 



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