RESEARCH NEEDS 



A detailed review of the literature 

 results in the conclusion that the data 

 base available for projecting biological 

 impacts of minor shoreline structures is 

 extremely sparse. The research needs 

 are virtually unlimited for each type of 

 structure and for each coastal region. 

 It would be unreasonable to propose a 

 study on each structure type within 

 each coastal region that was designed to 

 determine the magnitude of each con- 

 ceivable type of impact. We have, there- 

 fore, proposed avenues of approach 

 that will result in timely and cost-effec- 

 tive answers to the questions most fre- 

 quently asked. 



Data used in determining biological 

 impacts of the shoreline structures are 

 usually drawn from three data bases. 

 The most applicable data base is the 

 one containing information on the chem- 

 ical, biological, cr physical impact of a 

 specific type of structure. Examples 

 would be articles on chemical releases 

 from resuspended sediments during the 

 jetty construction, fish attraction to 

 breakwaters, and changes in beach pro- 

 file due to groins. As is evident in the 

 text of this report, this type of infor- 

 mation is scarce. 



The second data base contains in- 

 formation on engineering considerations 

 in structure design. Examples would 

 be methodologies for calculating wave 

 impact, structural integrity, or changes 

 in littoral transport. This information 

 is often useful in determining biological 

 impact, but is not directly applicable. 



The third data base contains infor- 

 mation on biological phenomena that is 

 not related to a specific type of struc- 

 ture. Examples of this type of informa- 

 tion are the attraction of the fishes to 

 artificial reefs and other submerged 

 structures; dredging effects upon ben- 

 thos; and succession, diversity, pro- 

 ductivity, and biomass of the commun- 

 ities that foul submerged structures. 

 This information is useful if it can be 

 applied tc a specific type of structure. 



During the present study, infor- 

 mation was entered into the data base 



only when it was specific for a particu- 

 lar type of structure and a physical, 

 chemical, or biological environmental im- 

 pact. Information from the other two 

 data bases was not entered into the 

 system. During the present study, de- 

 scriptions of certain impacts recurred 

 through the literature. Examples of the 

 more significant recurrent impacts are 



Changes shoreline dynamics 



Affects littoral transport 



Changes wave energy 



Changes sediment composition 



Increases turbidity 



Causes suspension of toxic 



chemicals 



Changes dissolved oxygen, 



salinity, or temperature 



Shades the water 



Affects circulation 



Alters existing habitat or 



creates new habitat 



Alters species composition 



Affects migration patterns 



Socioeconomic changes due to 



increased area usage 



A study should be performed to 

 analyze each of the recurrent types of 

 impacts based on each of the three data 

 bases. For example, the effects of in- 

 creased turbidity due to any of the 

 structures would be a valuable study. 

 An impact approach in addition to a 

 structural approach would result in a 

 considerable refinement of the conclu- 

 sions reached in this report. 



Review of available literature un- 

 covered certain major gaps in the data 

 base. The following recommended stud- 

 ies would help to fill in some of these 

 areas where information is lacking. 



o How are biological communities af- 

 fected by structures which stabi- 

 lize shorelines? 



o How do changes in wave energy 

 patterns affect biological commun- 

 ities? For example, what are the 

 differences in communities in front 

 of and behind breakwaters? 



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