Inland Underwater Pipe Installation 1

[UConDoIt]

I am working on a budgetary cost estimate (apx 30%). I have to deliver 250 cfs of water out of a river appx 3 miles to the toe of a dam where it will attach to and outlet from the downstream side of the dam through a sluice pipe. About 2 miles is under about 100 feet of water in a long, narrow reservoir, located off Hwy 70 (a long windy road) in the Sierra Nevada mountain range (CA).

I would like to know what equipment (along with mobilization and construction costs) will be necessary to lay the pipe on the bottom, which will require some dredging to keep a consistant slope for gravity flow. There is about 100 feet of head.

Thanks.

 

[civilperson]

Clam-shell bucket with barge mounted crane,($2500/day plus mobe).

 

[kenvlach]

Re "pipe on the bottom, which will require some dredging to keep a consistant slope for gravity flow."

You don't need a constant slope for gravity flow. Can go up & down by siphon effect (as long as no significant leaks).
The section of the LA Aqueduct, completed ca. 1913 (some work continued to 1916):

'The south end of the Jawbone Siphon, an 8,095 foot steel pressure siphon.'

 

[StephenA]

Kenvlach
On land air release valves are placed at high points. They are not normally used underwater due to maintenance considerations. Therefore it is advisable to have a fall, albeit not constant, underwater.

UConDoIt
Use a HDPE pipe with concrete weight collars, which can be launched as it is welded together and then installed by the S-Lay or Float Flood method. Being in a reservoir you will not need very big collars as the wave forces are low.



Stephen Argles
Land & Marine

http://www.landandmarine.com