pipe is assembled on and laid by the floating barge, which travels 

 the length of the line. Earthen plugs, dams, riprap, or bulkheads 

 may be required wherever a canal intersects another waterway in 

 order to prevent drainage, erosion, and navigation traffic. When- 

 ever open water is traversed, the same equipment is used, although 

 only a trench will be dredged. If a hydraulic dredge is used, 

 spoils may be pumped to nearby land, dispersed over the adjacent 

 area, or piled up in a spoil island. Normally, flotation canals are 

 not backfilled due to their large size. Straight open-water canals 

 flanked by low spoil levees are the final product of the flotation 

 method. 



Once pipelines are pressure checked and operating, they are period- 

 ically inspected for leaks; boats, marsh buggies, or aircraft may be 

 employed. The equipment utilized and traffic frequency depends on 

 the nature of the pipeline, its size, and the local marsh 

 conditions. 



2. Primary ecological alterations 



2.1 Partial vegetation loss within line easement due to trampling 

 and crushing effects of construction machinery 



2.2 Complete loss of vegetation within canal zone 10 to 100 m (30 

 to 300 ft) wide and on disjunct spoil disposal areas 



2.3 Partial or complete removal of consumer groups, depending on 

 the type of line and placement methodology utilized 



2.4 Increased concentration of suspended sediments and dissolved 

 nutrients 



2.5 Creation of pathways increasing saltwater inflow 



2.6 Creation of pathways increasing the rate of freshwater runoff 



2.7 Blockage or alteration of existing marsh drainage patterns due 

 to levee construction and canal excavation 



2.8 Change in inundation frequency of localized areas 



223 



