effects on vegetation types may result from changes in waterflow regimes, 

 the areal extent of surface damage and impact on consumers are minimal. 



Site access by leveed road . 



1. Activity sequence 



Surveyors enter the marsh by truck, marsh buggy, or foot, stake the route, 

 and leave the area. The staked route may or may not be the most direct 

 pathway to the wellsite location. A dragline with board mats enters the 

 site to excavate a continuous borrow pit and place the spoil to form a 

 long continuous levee. The dragline proceeds along the marsh surface on 

 that side of the levee from which the fill is borrowed and parallel to 

 the levee route. The fill is placed in a continuous pile 10 to 13 m 

 (30 to 40 ft) wide with an approximate slope of 30°. Three to 4 m (about 

 10 ft) usually remains as a berm, that distance between the foot of the 

 levee and the edge of the borrow pit. The dragline shapes the material 

 only approximately and then leaves it to drain and dry. A board road is 

 placed on the top of the levee after synthetic material is laid to con- 

 trol water seepage. The dragline may exit by traveling on board mats, or 

 if the roadway is completed, it may be loaded on a large equipment-moving 

 vehicle. 



Primary ecological alterations 



2.1 Creation of ruts or depressions in land surface - marsh buggy tracks 

 and/or tracks from other accessory equipment 



2.2 Loss of vegetation along road pathway due to excavation and covering 



2.3 Increases in concentrations of suspended sediments and dissolved 

 nutrients 



2.4 Blockage of normal surface-water flow patterns by levee 



2.5 Creation of a pathway 2 to 5 m (6 to 15 ft) deep parallel to levee 

 for more rapid upland drainage and standing water from marsh 



Attribute alterations 



i 



Surveyors and their equipment trample and crush vegetation outside the 

 zone to be excavated, but the area involved is small. Furthermore, much 



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