cleaning up accidental spills should be 

 provided (Coastal Plains Center for 

 Marine Development Service 1973). 



Socioeconomic . Small craft harbors 

 can be more economically placed in the 

 areas of low wave energy requiring few- 

 er protective structures (Bauer 1973). 

 This type of environment, which includes 

 estuaries, bays, and marshes, is also 

 highly productive for natural resources. 

 Therefore, the economic and biological 

 costs and benefits must be weighed 

 when siting a marina. 



Biological . During construction and 

 operation of a marina, any unnecessary 

 disturbance of adjacent areas should be 

 avoided. Wetland and marsh habitat 

 should be protected. Turbidity control 

 devices should be used when necessary. 

 Vehicles designed to minimize soil com- 

 paction should be used when working in 

 wetlands. Shellfish beds are mentioned 

 often as a particular area of concern 

 (Coastal Plains Center for Marine Devel- 

 opment Service 1973, Florida Department 

 of Natural Resources 1973, Snow 1973). 

 Shoreline vegetation should be left in 

 place and used to aid in shoreline sta- 

 bilization (Florida Bureau of Environ- 

 mental Protection 1975). Wetland areas 

 should be avoided as sites for fill and 

 surfacing (Clark 1974). 



Giannio and Wang(1974) recommend 

 using dredge spoils from the marshes to 

 establish new marshes elsewhere. Ef- 

 forts should be made to create new hab- 

 itats if possible. For example, riprap is 

 recommended over bulkheading because 

 it provides better habitat for sessile 

 organisms. Biological impacts due to the 

 various structures contained in small 

 boat harbors should be considered in 

 the total harbor evaluation. (Refer to 

 the sections on Breakwaters, Piles and 

 Piers, Buoys, Floating Platforms, Ramps, 

 Groins, Jetties, Bulkheads and Revet- 

 ments. ) 



Construction Materials 



Harbors may contain one or more 

 of the various small structures discuss- 

 ed in other sections of this report. The 

 other sections should be consulted for a 

 discussion on the various types of con- 

 struction materials used in harbors. 



Expected Life Spa n 



The expected life span of a small 

 boat harbor was not discussed in the 

 literature. The life span of a harbor 

 is dependent on the durability of the 

 various structures that make up the har- 

 bor, particularly breakwaters or jetties 

 which protect the entrance channel and 

 basin. Specific sections of this report 

 dealing with breakwaters and jetties 

 should be consulted. 



Summary of Physical and Biological 

 I mpacts 



C onstruction effects. Numerous ac- 

 tivities can be involved in harbor con- 

 struction depending on the features of 

 the harbor. One should consult the ap- 

 propriate section of this report for in- 

 formation pertaining to the impacts of a 

 specific structure. Major considerations 

 are turbidity and the release of trapped 

 toxicants from sediments. 



Chronic effects. The impacts of a 

 small craft harbor are dependent on site 

 characteristics, the design of the har- 

 bor, and the extent of alterations that 

 were made on the environment (Clark 

 1974). Carlisle (1977) states that there 

 is generally no normal benthic succes- 

 sion, poor substrate, and poor water 

 quality in harbors. Ross (1977), on the 

 other hand, maintains that marinas do 

 not necessarily produce poor water cir- 

 culation and anoxic conditions. Although 

 opinions varied in the literature, water 

 quality should be considered during har- 

 bor design. 



The function of a small craft har- 

 bor dictates the need for calm water 

 which can lead to stagnation and con- 

 comitant water quality problems. Dead 

 end canals or basins with inadequate 

 flushing create stagnant water. This 

 stagnant water can experience larger 

 temperature and salinity changes than 

 adjacent areas. Wick (1973) states that 

 the "square-shaped boat basins require 

 dredging and filling, and create dead 

 water areas - all adversely affecting 

 the natural flow system." Poor circula- 

 tion of the water can lead to a buildup 

 of organic sediments and depletion of 

 dissolved oxygen. 



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