PART III: REVIEW OF DETACHED BREAKWATER 

 PROJECTS IN THE UNITED STATES 



13. Although experience in the use of segmented detached breakwaters in 

 the United States is limited, there have been a number of applications in 

 other countries. In addition, single detached breakwaters have a long history 

 along the shores of the United States. These structures range from low (fre- 

 quently overtopped) structures located near the shoreline to high (deepwater) 

 structures built in association with a harbor. Single detached breakwaters 

 have been built by individual property owners and by all levels of Government, 

 and thus exhibit different intents, designs, and construction. 



14. A general impression of the performance of detached breakwaters as 

 shore protection and some functional design guidance can be gained from a re- 

 view of previous projects. In general, detached breakwaters in the United 

 States are straight, shore-parallel, rubble-mound structures with project 

 lengths ranging up to 600 m, distance offshore spanning roughly 46 to 600 m, 

 crest elevations varying from +0.4 m above local low water datum to +5.5 m and 

 the mean water depth at the structures ranging from 0.3 to 7.6 m below local 

 low water datum. One must be especially careful in drawing general conclu- 

 sions based on the shoreline response of any individual project, because his- 

 tory and configuration vary considerably. At least two single detached break- 

 waters (Santa Barbara and Venice, California) were eventually connected to 

 shore by additional construction. The Lakeview Park, Ohio, segmented project 

 has terminal groins. Three projects, Lakeshore Park, Ohio, Colonial Beach, 

 Virginia, and East Harbor, Ohio, are new projects which are still evolving. A 

 summary of these breakwater projects can be found in Table 1 on page 39. 



Single Detached Breakwaters 



15. A few major projects illustrate typical types of single detached 

 breakwater applications (SPM 1984). One of the first was the Venice, Califor- 

 nia, rubble-mound breakwater. This structure was originally built to protect 

 an amusement pier, and although the beach has been periodically eroded by 

 storms, a tombolo has always returned. Another example project where a single 

 detached breakwater was built for erosion control is Haleiwa Beach, Hawaii. 

 Breakwaters built at Santa Barbara and Santa Monica, California, were ori- 

 ginally intended to create harbors of refuge; however, both projects trapped 



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