2.4 Introduction of toxic chemicals into the site's soils 



2.5 Displacement of sensitive wildlife species from adjacent areas due 

 to treatment processes and periodic human activity 



3. Attribute alterations 



Conversion of a well, if it should happen to be located on a natural 

 levee, to production status creates few additional site alterations. All 

 activities occur around the wellhead and central pad area. Operation 

 consists of periodic maintenance and inspection visits. Equipment repair 

 may occasionally require limited activity on the pad. Outlying portions 

 of the pad revegetate following reduced disturbance levels. Conse- 

 quently, considerations of the primary ecological alterations are 

 concerned primarily with the construction and operation of a new central 

 treatment complex. 



Attribute alterations are similar in scope but smaller in scale than 

 those of wellsite preparation. Site preparation for the treating complex 

 removes all biotic components within the construction boundaries through 

 cutting and clearing, grading, filling, and excavation activities. A 

 direct loss of approximately 0.4 ha (1 acre) of sustaining habitat 

 results for primary and secondary consumers. Food and cover elmination 

 is particularly significant for small mammals, breeding songbirds, and 

 soil invertebrates as proportionally larger portions of their resource 

 base is altered. Secondary consumers are affected indirectly by the 

 removal or reduction of herbivorous prey organisms as well as loss of 

 cover. Nesting, foraging, escape, and resting areas are altered or 

 destroyed. Avian and mammalian species vary widely in their tolerance to 

 habitat disturbance. Some species tolerate little alteration, while 

 others are found only in severely disturbed situations. In each case, 

 species response is a function of time elasped and the creation or 

 destruction of the required niche. Impact magnitude is a function of the 

 species resource base (home range size) and the indispensability of the 

 removed vegetation. 



Removal of plant cover encourages surface-water runoff from barren, newly 

 exposed sediments into adjacent aquatic systems. The resultant effects, 

 partially regulated by slope, are usually restricted in areal extent. 

 Interruption of detrital and nutrient cycles, with subsequent nutrient 

 reserve depletion through runoff and leaching, inhibit rapid plant 

 recovery following site abandonment and restoration attempts. 



Soil structure within the construction easement is decreased by the 

 compacting mechanisms of vehicular traffic, poured concrete foundations, 

 and other impervious linings. Water infiltration rates are reduced by 

 losses of soil porosity, thereby decreasing soil moisture and water 

 percolation through the soil. Surface-water runoff, intensified by 



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