2.5 Introduction of toxic materials into the site's water and soil 

 systems 



2.6 Displacement of sensitive wildlife species from adjacent areas due 

 to treatment processes and constant human activity 



2.7 Alteration of water flows in localized areas 



2.8 Changes in land elevations 



Attribute alterations 



Conversion of a well to production status creates few additional site 

 alterations. In the case where drilling was conducted from a special 

 barge, the capped wellhead is enclosed by a small elevated platform 

 supported by concrete pilings with a concrete and metal superstructure. 

 The barge is subsequently removed. Platform construction and barge 

 removal cause localized increases in suspended sediments. The effects, 

 however, are very temporary and restricted in scope. Consequently, 

 further considerations will not address the very small-scale alterations 

 generated at the existing wellhead location, but will concentrate 

 primarily on the ecological alterations uniquely associated with the 

 construction and operation of a central treatment complex in unmodified 

 marsh. 



Some attribute alterations are similar in scope but larger in scale than 

 those of wellsite preparation; other alterations are quite similar to 

 site preparations conducted in brackish, salt, or fresh marshes. Typ- 

 ically a central production complex includes a combination of elevated 

 structures and reworked marsh sites - areas that have been filled and 

 stabilized. Naturally high spots are favored locations. Site prepara- 

 tion for the treatment complex removes all biotic components within the 

 construction boundaries through dredging, spoiling, digging, filling, and 

 pile-driving activities. A direct loss of approximately 2 to 4 ha (5 to 

 10 acres) of sustaining habitat results for primary and secondary con- 

 sumers. Food and cover losses are particularly significant for small 

 mammals, local insect populations, and some aquatic invertebrates as 

 proportionally larger portions of their resource base are removed or 

 altered. The carrying capacity of the marsh for supporting secondary 

 consumers .such as the predatory mammals and birds, waterfowl, wading and 

 shorebirds, alligators, and aquatic vertebrates is certainly reduced by 

 such habitat alterations. The significance of such an incremental loss 

 at the ecosystem level of consideration is unknown, however. Evaluation 

 must be made in context with other surrounding or associated alterations. 



Reworking the marsh substrate to build ring levees and spoil pads, as well 

 as placing pilings and other support structures, causes increased levels 



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