Intake Design 2

[jvoisin]

I am looking for some input on how to size a water intake.

It is for a smaller distribution system. Phase 1 max day is 882m3/day and ultimate is 3628.8m3/day. The intake has to be HDPE, and I think it will be in the 300mm diameter range.
Also, are there manufacturers in Ontario that supply pre-cast pipe anchors for sinking?

Thanks
Joe

 

[QualityTime]

I would like to add the following:

1. You need to determine what the historical high water level (HWL) and the historical low water level (LWL) is where your intake is located. There are government publications that can tell you that. That gives you your design envelope.

2. You then figure out the head loss in the intake piping to determine what the HGL is in the low lift wetwell at HWL and LWL conditions. At LWL you will need to ensure the pump is flooded with adequate submergence to prevent vortexing. This will set depth of your wet well.

3. Always check that on power failure, the oscillating surging water in the wetwill will be contained by the walls of the wetwell or there is an overflow pipe set at the proper elevation.

4. For a small system like yours, it may very well be that there is not much head loss in the HGL and the wetwell may not be required to be very deep. Therefore protecting the intake pipe close to the shoreline becomes the governing factor and that in turn forces the wetwell to be deeper in order to have the pipe trenched into the bedrock.

 

[jvoisin]

thanks gents

 

[stanier]

You aslo need to check that at HWL the differential head of the pump is not such that it runs off the curve or even at BEP >115%. You may need to have a flow control valve to protect the pump.

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