PART II: SUMMARY OF CORPS BREAKWATER 

 AND JETTY STRUCTURES IN SPD 



3. SPD has a total of 28 projects which include breakwater and/or jetty 

 structures. Fourteen of these projects are within the US Army Engineer Dis- 

 trict, San Francisco's (SPN's), boundaries, and 14 are within the US Army 

 Engineer District, Los Angeles's (SPL's) area of responsibility. Locations of 

 these projects are shown in Figures 1 and 2. Overall, there are approximately 

 171,870 lin ft* of breakwater and/or jetty structures in the Division. Break- 

 waters account for about 60 percent of this total, and the remaining 40 per- 

 cent are jetty structures. Although a variety of construction methods and 

 materials have been used, most of the structures (97 percent) are constructed 

 entirely of stone. Other construction materials used include concrete armor 

 units (dolosse, tetrapods, tribars, quadripods), concrete blocks, concrete 

 sheet pile, and concrete monolith walls and head sections. 



4. Twenty-one of the projects are situated in an ocean environment, and 

 seven are located in the San Francisco Bay area. Many of the Pacific Ocean 

 structures are periodically subjected to very severe storm wave conditions 

 which have resulted in frequent maintenance and/or modifications at some 

 locations. Structures within SPD have experienced problems in all four major 

 REMR problem areas (runup and overtopping, localized damage, toe stability, 

 and use of dissimilar armor). Twenty-one of the Division's 28 projects have 

 been repaired or modified since construction. 



5. Most breakwaters and jetties in SPD have been constructed on top of 

 existing sediments (usually fine to coarse sand); however, portions of some 

 structures are constructed on bedrock. These structures have crest elevations 

 ranging from 10 to 26 ft and crest widths ranging from 6 to 26 ft, and they 

 have been constructed in water depths ranging from 8 to 45 ft. Side slopes 

 vary from 1V:1.25H to 1V:5H. Design guidance for breakwater cross sections 

 (stone sizes, crest height, width, etc.) is provided in the Shore Protection 

 Manual (1984) or appropriate CE engineering manuals. Several of SPD's proj- 

 ects have been model tested at the US Army Engineer Waterways Experiment 

 Station (Baumgartner , Carver, and Davidson 1985; Baumgartner, et al. 1986; 

 Bottin, Sergeant, and Mize 1985; Bottin and Acuff 1985; Bottin (in prepara- 

 tion); Brasfeild 1965; Brasfeild and Ball 1967; Carver 1984; Chatham 1968; 



* A table of factors for converting non-SI units of measurement to SI (met- 

 ric) units is presented on page 3. 



