Effects which are long term and large in areal extent may result 

 from induced changes in waterflow regimes. These effects, of 

 course, can occur only if trucks, buggies, or other surface vehicles 

 are used. The total area affected (and thus, the kinds and numbers 

 of consumers) is site specific. 



Site access by leveed road. 

 1. Activity sequence 



Surveyors enter the marsh by truck, marsh buggy, or on 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. f 

 board road is placed on the top of the levee after synthetic mate- 

 rial is laid to control water seepage. The dragline may exit by 

 traveling on board mats, or if the roadway is completed, may be 

 loaded on a large equipment-moving vehicle. 



2. 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 withinthe construction easement due to 

 excavation and covering 



2.3 Creation of borrow ditch 2 to 5 m (6 to 15 ft) wide and 1 to 

 2 m (3 to 6 ft) deep for increased saltwater inundation 



2.4 Increases in concentrations of suspended sediments and dis- 

 solved nutrients 



2.5 Blockage of normal surface-water runoff pathways by levee 



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