siphon pipe to drain a pond during emergency or for maintencance

[pkcola]

Can someone please tell me how to get a discharge rating for a siphon pipe that is to be used in a pond, It will only be used to drain the pond for maintenance or emergency.

Thnaks

 

[cvg]

no different than any other pipe flow analysis. estimate the available head. assume a starting pipe flow rate. estimate the entrance loss. estimate the pipe friction loss. estimate any minor losses. estimate any exit losses. add all the losses together and they should equal the available head. if not, adjust your flow rate and iterate until balanced.

 

[chicopee]

By discharge rating, I am not sure what you are looking for, however, see my JPEG attachment for the time it will take to drain a pond. It is a typical equation found in fluid mechanics textbooks. No inflow into the pond is considered.

 

[cvg]

or just use the attached graph

 

[Drew08]

Or just solve the balanced energy equation for Q:

Hreservoir (above outlet) = (Ke+1)(Q/A)^2/2g + L[nQ/(1.49AR^(2/3)]^2

 

[thatdamengineer]

Just for a bit of practical experience, I once lowered a 120 acre lake 2 ft per day with 2 16 inch welded steel siphons and 1- 24 inch one. This was during an emergency caused by throttling of the intake tower outlet and also during the rainy period, so we had inflow dfrom over 10 inches of rain the 2 weeks earlier..

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