with sensitive taxa being replaced by 

 those with a wider ranee of tolerance 

 (G if ford 1977). Breakwaters are func- 

 tionally located in high-energy environ- 

 ments that are usually typified by rath- 

 er coarse sediments. The area seaward 

 of a breakwater would be expected to 

 develop a coarse-sediment environment, 

 especially if compared to the previously 

 existing deeper bottom, a low-energy 

 environment. The enclosed area land- 

 ward of the breakwater will, in many 

 cases, develop a sediment composition 

 that is less coarse than previously 

 existed. This shift in sediment type 

 will cause concomitant shifts in species 

 distribution, diversity, and numbers. 

 These shifts can be either beneficial or 

 detrimental. 



The creation of a new type of bot- 

 tom often results in replacement of a 

 deepwater fish habitat with a shallow 

 shellfish habitat (Snow 1977). This will 

 depend upon the biology of the area 

 where the breakwater is constructed. 

 If sand deposition creates an emergent 

 or intertidal sandbar, then a new type 

 of bird habitat may result. The stone 

 surface upon and behind the breakwater 

 may be used by birds. The sandbar 

 and rock habitats are preferred by the 

 gulls, terns, and other beach-dwelling 

 species. Colonial nesting may occur if 

 human disturbance is limited during 

 nesting season. 



Breakwaters can affect longshore 

 fish migration routes. This has been 

 documented for salmonid fry where the 

 presence of a shore-connected breakwa- 

 ter forced them into deeper water than 

 previous conditions afforded (Stockley 

 1974). The reduction of shallow water 

 areas decreased the available salmonid 

 fry migration routes. The fry were ex- 

 posed to increased predation because 

 they would not migrate around the 

 structure. The effects of floating break- 

 waters are generally less severe and 

 the Washington Department of Fisheries 

 (1971) strongly recommends their use to 

 protect fish resources. Water circula- 

 tion is only slightly affected, and the 

 piling-up of water behind the floating 

 breakwaters is negligible because they 

 are anchored by cables or widely spac- 

 ed piles (Kowalski 1974b). Installation 

 causes much less disturbance of bottom 



habitat, though any setting of piles or 

 permanent anchor blocks would cause some 

 minor suspension of sediments. 



Once in place, floating breakwaters 

 provide a substrate for fish, algae, and 

 sessile organisms. They interfere only 

 minimally with fish migration. By shad- 

 ing the bottom, floating breakwaters can 

 reduce productivity, but the prolifera- 

 tion of attached organisms and the graz- 

 ers which they attract may balance or 

 offset their reduction (Gifford 1977). 



Cumulative effects . Very little 

 information was found on the cumulative 

 effects of breakwaters or breakwaters in 

 combination with other structures. If 

 two or more fixed structures are placed 

 in proximity, the resultant alteration 

 in current patterns could cause scour 

 damage to one or more of the structures. 

 The location of structures close to each 

 other can cause other synergistic ef- 

 fects: littoral transport modifications, 

 alterations of wave energy environments, 

 and alterations of water quality parame- 

 ters, such as salinity and dissolved 

 oxygen or the concentration of petro- 

 chemicals. The degree of such changes 

 must be evaluated case-by-case. 



Structural and Nonstructural 

 Alternatives 



Breakwater design is a function of 

 the shape of the structure or area to be 

 protected, and the direction and sever- 

 ity of the wave attack. Given these two 

 conditions, the breakwater cross-section 

 and construction materials will be se- 

 lected on the basis of materials avail- 

 ability and cost minimization. There are 

 several possible alternatives to propos- 

 ed breakwaters. 



It is possible to dispense with the 

 breakwater and devise other means to 

 deal with the wave attack on the harbor 

 or structures. The higher wave climate 

 could be dealt with by increasing the 

 structural design of piers, floats, ves- 

 sel mooring systems, and other features 

 of the harbor. This response is gener- 

 ally more feasible in harbors for large 

 ships because small craft cannot take 

 repeated pounding against structures. 



If the shoreline must be protected, 



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