will be decreased in the area under the 

 pier. This can include vegetation, 

 algal, and shellfish productivity. Grass- 

 beds will also be affected by resultant 

 boat traffic as will the fish activities. 

 Carstea et al. (1975a) recommends that 

 grass beds and other areas of signifi- 

 cant natural resource productivity be 

 avoided as sites for pier construction. 



Wooden structures in this area 

 should be properly treated against ma- 

 rine wood borer attack, although the 

 problem of attack against treated wood 

 piles should not be as extensive as in 

 some of the warmer coastal waters to 

 the south. The gribble (Li mnoria tri- 

 punctata ), considered to be the species 

 causing the greatest threat to creosote 

 and coal tar treated piles, only breeds 

 where the temperatures are above 57°F 

 (14°C) and is, therefore, not prevalent 

 in Coastal Region 7 (Lindgren 1974). 



A single residential pier is not 

 likely to have an extensive impact on 

 recreation in the general area. How- 

 ever, several piers in the area may re- 

 strict recreational activities and shore- 

 line access. Pier size and number like- 

 wise affect socioeconomics of the area. 

 Piers used in connection with a launch- 

 ing ramp or marina may cause increased 

 usage of the area and affect property 

 values or ecological relationships. 



The possible alternatives to a tim- 

 ber pier used for moorage in this area 

 would include solid-fill piers, anchor 

 buoys, single piles, dolphins, placement 

 of boats in local marinas, or land stor- 

 age. The use of anchor buoys or piles 

 would cause less adverse impact to the 

 environment. The use of a solid -fill 

 pier would, in most cases, be an unsat- 

 isfactory alternative due to the influ- 

 ence it would have on water movement 

 and sediment transport. 



A single, properly designed and 

 constructed open-pile pier would cause 

 relatively little adverse impact to local 

 biota. Host of the impact would be as 

 a result of related activities, such as 

 dredging or increased usage of the 

 area. 



CASE HISTORY - JETTIES IN COASTAL 

 REGION 7 - NORTH ATLANTIC 



Except for Long Island, little in- 

 formation on jetties in the New England 

 area was found. The amount of biologi- 

 cal data was minimal and was generally 

 applicable to most of the United States 

 coastline (Carstea et al. 1975a). 



Fire Island Inlet on Long Island 

 has a documented history extending 

 back to 1825. Fire Island is a long bar- 

 rier beach lying off the south shore to 

 Long Island. It is broken by a number 

 of inlets, many of which have been sta- 

 bilized by jetties. The Fire Island Inlet 

 is unusual in that two sections of the 

 barrier beach, Fire Island and Oak 

 Beach, overlap and the inlet curves be- 

 tween them. An irregular channel is 

 maintained by strong tidal currents in 

 the inlet, but throughout its recorded 

 history the channel has maintained its 

 S-shape. Over the years both erosion 

 and accretion has occurred so that Fire 

 Island has grown toward the west and 

 Oak Beach has been cut back (Shepard 

 and Wanless 1971). 



A jetty was completed at Democrat 

 Point in 1941. This temporarily stopped 

 the westward advance of Fire Island. 

 The outer beach soon filled behind the 

 jetty on the south side of the island. 

 Following this, sand was deposited land- 

 ward of the north side and caused a 

 bar to develop. The bar eventually 

 reached nearly across the inlet to Oak 

 Beach. As the channel narrowed, the 

 strength of the tidal currents increas- 

 ed, and severe erosion occurred on Oak 

 Beach. The beach was artificially nour- 

 ished and a new channel cut, but the 

 latter soon filled. A second jetty was 

 built and erosion has apparently stop- 

 ped; however, an adequate channel does 

 not exist through the inlet (Shepard 

 and Wanless 1971). 



Jetties, as with other shoreline 

 structures which interrupt littoral drift, 

 upset the natural beach processes and 

 cause unwanted and sometimes unfore- 

 seen erosion and accretion (Davis et al. 

 1973). This is well illustrated by the 

 changes in Fire Island Inlet. Not shown 

 were the effects of these changes on 

 the plants and animals of the area. No 

 information was given on habitat loss or 

 alteration. It can be assumed that the 

 construction and existence of the jetties 



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