New techniques are now available for laying pipelines in wetlands. 

 One of these, the "push" method, eliminates the need for a pipe-laying 

 barge to enter the wetland; a V-shaped trench is dug through the wetland 

 (the width is dependent on the cohesiveness of the wetland soil). The 

 pipeline is then assembled and pushed ashore from the back of the barge. 

 (The pipeline can also be pulled from the far end with a cable attached 

 to a winch. ) 



Another new method uses a smaller channel than the traditional 

 method— a canal for a shallow-draft pipe-laying barge is dug with a V- 

 shaped trench in its center. The pipeline is fed into this trench and 

 covered as the barge advances across the wetland. 



Onshore Pipelines : Previous sections have dealt with the pipeline 

 from offshore to the "shore destination," the first receiving point--a 

 gas processing plant or an oil transfer terminal or refinery. From this 

 point through the uplands area, the siting and construction of the 

 pipeline is not greatly different from other upland construction. There 

 are also close similarities with power transmission line corridors and 

 utility corridors insofar as the effects on the terrestrial environment 

 are concerned. The following information also applies to the sections 

 from landfall to shore receiving point. From the landfall to the 

 processing plant, refinery, or transfer terminal, the pipeline is of the 

 same dimensions as the pipe coming onshore. It is probably constructed 

 of the same material and may be given a protective wrapping but would 

 not be coated with concrete, thereby having a smaller overall size. 



The corridor for onshore sections of the pipeline inland from the 

 shore receiving point will range from about 50 to 75 feet and follow the 

 shortest possible route. It will be buried at a depth of 4 to 6 feet. 

 Pipelines would normally avoid natural obstacles such as lakes or rivers, 

 but where necessary the pipeline may span large rivers or be installed 

 under smaller rivers and streams (Figure 21). 



Figure 21. Directional drilling for pipeline installation under 

 rivers and streams (Source: Reference 27). 



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