d) As each new section is eardy to move into canal, 

 tug and winches move lay barge ahead one pipe 

 length over pipe ditch - note, no flotation 

 devices 



e) Backfilling usually not done due to draining and 

 compaction of dredge spoil - some owners require 

 backfilling with spoil from other locations 



5) Barge and dredge removal from site, bulkheading 



a) Barges removed from area by tug 



b) Canal bulkheaded - see steps II.F.2.b.3 

 Open-water pipeline laying - bays (0.25-1.5 km/day) 



1) Survey route 



a) Boat placement of marker buoys 



2) Lay barge moves to site by tug or self power 



3) Pipeline fabrication and lowering - all activities 

 IV.A.l.a.6 to IV. A. 1. a. 8 done at stations on lay barge 



a) Pipe positioned on line and welded (several welds) 



b) Welds cleaned, series of coatings placed on pipe 



c) As each new section is ready to move into water, 

 tug and winches move lay barge ahead 



d) Dredging sled with hydraulic jets follows lay 

 barge - jets loosen bottom material, pipe slips 

 into hole 



4) Barges reach end of line 

 River and stream crossings 



1) Small, nonnavigable streams (2-3 days) 



a) If stream narrow enough, pipe bent upward and 

 crosses above water level 



b) Narrow stream, pipe buried under bottom 



(1) Dragline excavates at trench across stream 



(2) Pipe is bent into shallow "U", welded and 

 wrapped - see steps IV.A.l.a.5 to 



IV. A. 1. a. 8 - Pipe may have weights attached 



(3) Pipe may be capped and floated or dragged 

 across river 



(4) Pipe positioned by cranes and lowered into 

 ditch 



(5) Pipe tied into other ends of pipe - see steps 

 IV.A.l.a.8.a.2, IV.A. l.a.8.a.4, or 

 IV.A.l.a.S.b 



(6) Ditch may be filled with coarse gravel or 

 materials which will not wash away with water 

 movement 



(7) Bulkhead constructed where pipe leaves land 

 to channel - see steps II.F.2.b.3 



c) Wide deep river or channel (10-14 days) 



(1) Depending on depth, width, may use dragline 

 on barge and spoil barge to excavate ditch - 

 or may use hydraulic jet when pipe is set 



on bottom 



(2) String of pipe long enough to span river is 

 prepared - see steps IV.A. 1. a. 4 to IV.A. 1. a. 8 



(3) Floats attached to pipe and whole string 

 lifted (side booms) and pulled completely 

 across river 



436 



