alternatives to a breakwater are revet- 

 ments, seawalls, bulkheads, increased 

 beach cross-section, or other methods. 



To compensate for reduced water 

 circulation and attendant problems in- 

 side a basin protected by a breakwater, 

 a permeable breakwater or floating 

 breakwater could be substituted for a 

 fixed, solid structure. Floating break- 

 waters have the additional advantage of 

 being portable and, to some extent, re- 

 usable. 



In shallow water areas not subject 

 to severe wave attack, vertical wood 

 pile or sheet pile structures are often 

 used as breakwaters. If rock is avail- 

 able, a low, rubble mound structure 

 may prove equally effective and econom- 

 ical, while alleviating some of the envi- 

 ronmental problems associated with fixed 

 breakwaters and vertical surfaces. 



When the breakwaters are used to 

 create a basin, there is usually a shape 

 that will minimize the total cost and re- 

 duce the dredging required for the ba- 

 sin. Placing the basin in deeper water 

 may increase breakwater costs, but de- 

 crease dredging costs. The reverse is 

 also true. Assuming there is no problem 

 with property ownership or rights, the 

 shape of the basin can be altered to 

 achieve a different balance between 

 breakwater and dredging or between 

 development of water area versus land 

 area. 



R egional Considerations 



Breakwaters are found at virtually 

 every harbor and estuary on the north 

 Pacific coast (Coastal Region 1). They 

 are primarily intended to protect water- 

 ways from extensive wave action. The 

 State of Washington has outlined strict 

 guidelines for their design and place- 

 ment. These include the following phy- 

 sical placement criteria: at least two 

 gaps must be provided to allow water 

 circulation and flushing; the structures 

 must be less than 250 ft (69 m) from 

 MHHW (mean higher high water) line 

 and not be below ft MLLW (mean low- 

 er low water); facings must be perman- 

 ent material and stair-step design; the 

 openings must not be shallower than the 

 dredged enclosure. Vertical faces are 



considered undesirable because they pre- 

 clude a shallow water area, while 30-de- 

 gree slopes approximate natural condi- 

 tions. Though raw earth or gravel facings 

 are similar to the normal habitat of 

 juvenile salmon, they allow erosion and 

 damage shellfish beds (Washington De- 

 partment of Fisheries 1971). 



Limited data are available concern- 

 ing altered environmental conditions. 

 Algae and hydroids have been noted on 

 breakwaters in Puget Sound (Millikan et 

 al. 1974, Smith 1976) and fish were 

 abundant at one breakwater (Smith 1976). 

 Smith (1976) also reported three dis- 

 tinct zones of marine invertebrates 

 along a breakwater. Ricg and Miller 

 (1949) observed surf habitats on the 

 outer face of a breakwater and typical 

 quiet water types of sessile organisms 

 on the inner face. They also observed 

 an unexplained abundance of starfish at 

 one breakwater. Millikan et al. (1974) 

 noted large amounts of herring spawn on 

 evergreens submerged in the vicinity of 

 breakwaters; flocks of scoters fed 

 heavily upon the spawn. 



Physical impacts, as described in 

 the general section, were expected to re- 

 sult from the construction and presence 

 of breakwaters on the north Pacific 

 coast (Coastal Region 1). The major bio- 

 logical impact discussed was upon salmo- 

 nid fry which became vulnerable to pre- 

 dation due to an interference with mig- 

 ration (Richey 1971). In some cases 

 shellfish beds were destroyed by break- 

 water placement, but in others new clam 

 beds were established in sand accretion 

 areas. Shoaling around one breakwater 

 was expected to alter benthic habitat, 

 preclude bottom use by fish and shell- 

 fish, and create additional bird habitat 

 (U.S. Army Engineer District, Seattle 

 1971). However, Rigg and Miller (1949) 

 reported that another breakwater in 

 Puget Sound had no noticeable effect on 

 organisms in its vicinity after 10 yr. 



Most of the breakwaters in southern 

 California (Coastal Region 2) are asso- 

 ciated with harbors, often small boat 

 moorages. In a few cases, detached off- 

 shore breakwaters function as shore pro- 

 tection structures. Both shore-connect- 

 ed and detached breakwaters can be found 

 in this region, and most of these are 



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