the soil embankment will help prevent 

 loss of silt and clogging of the filter 

 (Dunham and Barrett 1974). 



structures 

 1975). 



(Bellis et al. 1975, Sanko 



Socioeconomic 



Bulkheads can se- 



recreational activities on 



Several au- 



verely limit 



shorelines (B rater 1954) 

 thors urge consideration of the effect a 

 bulkhead will have on access to public 

 beaches pn'or to construction (Coastal 

 Plains Center for Marine Development 

 Service 1973, McAllister 1577, Snow 

 1973). Bulkheads can affect swimming, 

 water skiing, diving, fishing, and 

 shellfishing (Carstea et al. 1975a; Center 

 for the Environment and Man, Inc. 

 1971). Borrow areas, which are some- 

 times created to provide backfill mate- 

 rial, may pose a hazard to unsuspecting 

 waders, swimmers, and fishermen. 



The appearance of a bulkhead, both 

 alone and as part of the overall shore- 

 line, is an important consideration. Snow 

 (1973) advocates designing bulkheads to 

 blend in with the surrounding shore- 

 line. The South Carolina Marine Re- 

 sources Division (1974) encourages ap- 

 plications for bulkheads that will aes- 

 thetically and/or ecologically enhance 

 the marine environment in areas that 

 have been extensively developed. This 

 agency also discourages bulkheads 

 which have sharp angle turns because 

 trash may accumulate there. 



Construction and maintenance costs 

 are an important determinant of the 

 type of structure built at a given loca- 

 tion. Bulkheads and seawalls are gener- 

 ally very expensive to construct and 

 maintain. Initial construction and main- 

 tenance costs for the design life of the 

 project vary, depending upon site con- 

 ditions, geographic region, materials 

 used, and massiveness and design of 

 the structure. Initial construction costs 

 can range from $30.00 to over $500.00 

 per linear foot of protection for more 

 massive seawalls. Local availability of 

 the suitable construction materials influ- 

 ences cost of the structures. The cost 

 of maintenance depends upon labor ex- 

 penses, material costs, and frequency 

 of repair. In general, poured concrete 

 structures are the most expensive to 

 build, with stepped designs more expen- 

 sive than either the vertical or sloped 



Biological . When planning bulkhead 

 construction, the effects of the struc- 

 ture on the total environment should be 

 considered (Committee on Government Op- 

 erations 1970). Numerous biological con- 

 siderations were found in the literature 

 which apply to most coastal regions: 



Bulkheads should be designed 

 so that reflected wave energy 

 does not destroy stable marine 

 bottoms (Florida Department of 

 Natural Resources 1973, South 

 Caroline Marine Resource Divi- 

 sion 1974). 



Bulkhead construction should 

 avoid sharp angle turns be 

 cause this may create flushing 

 or shoaling problems (Bauer 

 1975, South Carolina Marine 

 Resources Division 1974). 



Bulkheads should be designed 

 to minimize damage to fish and 

 shellfish habitats (Snow 1973). 



Vertically designed bulkheads, 

 especially when they protrude 

 out to minus tide levels in bays 

 and estuaries, eliminate protec- 

 tive habitat for salmon fry 

 (Stockley 1974). Stair-step de- 

 sign bulkheads or riprap revet- 

 ments on a 45 or less degree 

 angle provide protective habitat 

 for salmon fry (Heiser and Finn 

 1970). 



Toes of bulkheads should not 

 intrude into fish s paw nine 

 beaches (Millikan et al. 1974). 



Fill material should not be ex- 

 cavated from shallow water and 

 productive wetlands (Carstea 

 et al. 1976). 



When possible, existing shore- 

 line vegetation should remain 

 undisturbed and/or enhanced 

 for use in shoreline stabiliza- 

 tion (Florida Game and Fresh- 

 water Fish Commission 1975). 



48 



