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Thread: Error in Pump Discharge Flows

  1. #1

    Error in Pump Discharge Flows

    I've come across what seems to be an error in H2Omap SWMM where flows downstream of a pumping station are vastly different to the pumped flows. The pump operates for a short period of time at 20-30 L/s. In the downstream gravity main flows are less than 10 L/s. See attached graph.

    Has anyone come across this problem before and know how to fix it?
    Attached Images Attached Images

  2. #2
    Senior Member

    Innovyze Employee



    Join Date
    Feb 2013
    Posts
    146
    Hi Patrick,
    A few suggestions:
    1. You say gravity main but do you mean force main using Hazen Williams? A HW force main will react better to the pumped flows compared to the gravity main
    2. Did you had a surcharge depth to the node downstream of the pump so the link downstream is under pressure and stays on the pump curve?
    3. If you have a pump that turns on a lot of times you might need to use a smaller time step.
    4. If you are getting reverse flow then a flap gate should help
    5. If that does not work then send me your model to suppport@innovyze,com and I can comment
    Regards,
    Bob Dickinson

    PS Here are a few blogs about this matter

    http://blog.innovyze.com/2012/10/31/...summary-table/

    http://blog.innovyze.com/2012/10/12/...t-in-infoswmm/

    Pump / Force Main System in InfoSWMM and SWMM 5



    Subject: Pump / Force Main System in InfoSWMM and SWMM 5
    The basic system consists of:
    ·Wet Well and its associated physical parameters,
    ·Pump Type
    ·Defined Pump Curve,
    ·Downstream Pressure Node and
    ·Downstream Force Main
    Figure 1: The Basic System

    Step 1: Wet Well Data
    Enter the invert elevation, maximum depth of the Wet Well, the physical shape as either a function or shape table and any evaporation or infiltration.

    Step 2: Define the Pump Type
    The pump type is defined by a Pump Curve and the On and Off elevations:
    The four types of pumps are:
    ·Volume - Flow
    ·Depth – Flow
    ·Head – Flow
    ·Depth - Flow

    Step 3: Define the Pump Curve in the Operation Tab

    Step 4: Set a Surcharge or Pressure Depth at the Downstream end of the Pump
    Any positive Surcharge Depth in the Node will allow the program during the simulation to keep the node under pressure forcing flow through the Force Main.

    Step 5: Force Main Data
    Define the downstream pipe(s) from the pump as Force Main conduits with either a Hazen Williams or Darcy-Weisbach coefficient (defined in the SWMM 5 options or the Run Manager of InfoSWMM)


  3. #3
    Was anyone able to help you with this? I am having a similar problem.

  4. #4
    Senior Member

    Innovyze Employee



    Join Date
    Feb 2013
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    146
    Quote Originally Posted by Lucas Tipton View Post
    Was anyone able to help you with this? I am having a similar problem.
    Gladly, Lucas. Can you send me your ISDB folder (zipped) and MXD file to me at support@innovyze.com

    Regards,
    Robert Dickinson

    PS it looks like you sent it to my colleague so I will look at it now
    Last edited by Robert Dickinson; May 21, 2015 at 04:00 PM.

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