CONTENTS— Continued 



Page 



IX BREAKWATERS, OFFSHORE 5-61 



1. Definition 3-61 



2. Functional Operation 5-61 



3. Shoreline Response 5-63 



4. Siting Considerations 5-64 



5 . Design Considerations 5-67 



6. Other Considerations 5-71 



X ENVIRONMENTAL CONSIDERATIONS 5-74 



LITERATURE CITED 5-75 



TABLES 



5-1 Relationships of phi means and phi standard deviations of native 



material and borrow material 5-13 



5-2 Comparison of composite grain-size distribution parameters and 



beach fill, Brunswick. County, North Carolina 5-15 



5-3 Offshore breakwaters in the United States 5-62 



FIGURES 



5-1 General classification of coastal engineering problems 5-1 



5-2 Effects of erosion 5-5 



5-3 Isollnes of the adjusted fill factor, R^, for values of phi 



mean difference and phi sorting ratio 5-11 



5-4 Isollnes of the renourlshment factor, Rj , for values of phi 



mean difference and phi sorting ratio, A= 1.0 5-14 



5-5 Beach berm system 5-20 



5-6 Stabilized and migrating dunes 5-25 



5-7 Schematic diagram of storm wave attack on beach and dune 5-27 



5-8 Types of littoral barriers where sand transfer systems have 



been used 5-29 



5-9 General shoreline configuration for a single groin 5-36 



5-10 General shoreline configuration for two or more groins 5-36 



5-11 Three mechanisms for creating rip currents between groins 5-38 



5-12 Sections of a typical groin 5-40 



5-13 Three cases of a groin-adjusted shoreline 5-41 



