Wellsite preparation and operation for leveed marsh-floor locations. 



1. Activity sequence 



The equipment and techniques utilized during construction of the access 

 road are also employed during preparation of the wellsite. After sur- 

 veyors have staked the areas, the dragline constructs a ring levee around 

 the entire site by utilizing borrow from pits located exterior to the 

 levee. Outside dimensions of the levee are usually less than 120 by 120 

 m (400 by 400 ft). Initial levee height is about two m (six ft); shrink- 

 age occurs through time. A sump ditch is excavated immediately inside 

 and parallel to the entire levee. A board foundation similar to that 

 laid for the access road is placed over the wellsite area. Internal 

 earthworks are constructed and shaped by various pieces of equipment, and 

 the pad site is surfaced in a manner similar to that used for the access 

 road. A variety of auxiliary equipment and materials is moved to and 

 stored in the area prior to arrival of heavy drilling equipment. Drill- 

 ing activities require one to three months. Test results indicate whether 

 the well should be put into production or should be capped and shut down. 



2. Primary ecological alterations 



2.1 Complete vegetation removal inside the ring levee and in borrow pits 

 outside the ring levee 



2.2 Increases in concentrations of suspended sediments and nutrients 



2.3 Creation of pits and a ring levee which alter water flows in local- 

 ized areas 



2.4 Introduction of toxic materials to water and soil systems 



2.5 Extended displacement of wildlife from entire area adjacent to road- 

 way and wellsite 



3. Attribute alterations 



Construction of the wellsite is usually an extension of construction of 

 the access road; the dragline merely continues operation, excavating 

 disjunct borrow pits to build the ring levee. This work and the 

 auxiliary preparation of the wellsite interior removes vegetation and 

 associated insects from a maximum of 1.4 ha or 3.5 acres. This removal 

 represents a loss of food and cover for all the remaining consumer groups: 

 waterfowl, wading and shorebirds, mammals, alligator, aquatic vertebrates 

 and invertebrates, and insectivorous birds. 



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