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View Full Version : Some Pumping Station's Well Levels dropping before pumps turn on in InfoSWMM



Mathy Jegan
August 27, 2014, 10:20 PM
I am seeing few pumping station wet well levels start to drop down even before the pump turn on. Effectively the wetwell levels do not reach the duty cut off levels for number of times but going up and and down below the cut off levels.

Can this be explained please. I have pasted couple of examples. In one station the cut off depth is 0.804m. wet well rose many times but did not reach 0.804m all the times and had dropped down. Only the few time it reach 0.804m the pumps kicked on with spiky flows.

I was trying to paste or attach the model output graphs to this posting but not working for me.
Mathy

Robert Dickinson
August 28, 2014, 01:42 AM
Hello Mathy,
As I just mentioned from an email to you from support@innovyze.com your pumping flows versus Wet Well Depth is a function of the fast cycling times of the pumps and the depth averaging over the report time step in InfoSWMM. If you graph every 5 minutes while the pump is on for 5 to 10 seconds it will look as if the Wet Well depths are out of sync with the pump. If you graph every 10 seconds then the Wet Well depth graph averaging over the report time step will match the pump on and off depths exactly. I hope this helps and I will send you an example graph.
Regards,
Bob Dickinson
Innovyze Inc.

Robert Dickinson
August 28, 2014, 03:23 PM
I am seeing few pumping station wet well levels start to drop down even before the pump turn on. Effectively the wetwell levels do not reach the duty cut off levels for number of times but going up and and down below the cut off levels.

Can this be explained please. I have pasted couple of examples. In one station the cut off depth is 0.804m. wet well rose many times but did not reach 0.804m all the times and had dropped down. Only the few time it reach 0.804m the pumps kicked on with spiky flows.

I was trying to paste or attach the model output graphs to this posting but not working for me.
Mathy

It is hard to attach graphs, to answer your question i am embedding two graphs here

1. The 1st graph is reporting depths and flows at 10 seconds
2. The 2nd graph is reporting depths and flows at 60 seconds
3. As you can see the 1st graph shows the pump turning on at a depth of 3 meters and turning off at a depth of 1 meter
4. The 2nd graph with a longer time reporting time step looks like the pump does not turn of or off at the proper time
5. The pump operation is the same but the graphs look very different

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