After surveyors have staked the area, 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); shrinkage 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 well site 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. Drilling activities 

 require one to three months. Test results indicate whether the well 

 should be put into production or capped and shut down. 



Equivalent activities occur at a dredged location. The wellsite, or 

 keyway, has been previously dredged to dimensions of approximately 

 47 by 133 m (140 by 400 ft). Drilling and auxiliary equipment and 

 supplies are transported and stored on barges. A specialized barge 

 is employed for drilling. Its ballast tanks are flooded, it settles 

 to the bottom, and piles are driven to anchor it firmly in place. 

 Impacts are primarily due to the increased turbidity and noise 

 associated with traffic and drilling. These effects were discussed 

 in an earlier section of this report (site access by canal and 

 wellsite dredging) and will not be considered further. 



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 nutri- 

 ents 



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

 localized areas 



2.4 Introduction of toxic materials to water and soil systems 



2.5 Extended displacement of wildlife from entire area adjacent to 

 roadway, access canal, and wellsite 



Attribute alterations 



Construction of the wellsite is usually an extension of construction 

 of the access road; the dragline merely continues operating, excavating 



188 



