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RE: Pumpstation+Storage pipe

Ref: http://communities.bentley.com/products/hydraulics___hydrology/f/5925/t/102714

Hi

In the following captured, I included plan and section of a given stormwater pump station to evacuate water from wet well to a river from level 0.0 m to level 10 m.

I need to have the required volume of wet well for a given hydrograph.

I drew manhole, pipe , wet well, pump, pressure pipe and an outlet in SewerGems.

Aso,as you mentioned before, I input the 5-year event hydrograph in the node (manhole).

Please let me know:

1- How can I have volume required of wet well based on the hydrograph and pump discharge 2 x 0.2 m3/s.

2-Is it possible to have volume stored in the pipe in the different level form level 0.0 to level 2m?

This project should be done based on " HEC24, stormwater pump station guideline" and I should follow that book.

Regards.

Hamid

 

 

 

Parents
  • Hello Hamid,

    I'm not familiar with the guideline you mentioned but I'm confident you'll be able to use SewerGEMS to model this system.

    1) When you mention a flow of 0.2 cms, is that a constant flow out of the pump, the peak flow when the pump turns on, or something else? Typically pumps will turn on and off based on the level in the wetwell. So, the smaller the wetwell, the more frequent the pumps will be cycling. Therefore it may help to explain a bit more about the criteria for selecting a wetwell size. Generally speaking, you would enter a reasonable size in the model, compute, assess the results and resize as needed.

    2) When you say "to have", are you asking if there is a way to report the volume? This is not a result field for a conduit but you can view the profile to see the water surface and pipe depth. Again, it would help to provide a bit more information on why this is needed.

    Though it may not be necessary, if the storage pipe is relatively short and you don't need to asses it's capacity or a typical gradually varied flow profile, you could potentially combine the volume of the wetwell with the volume of the pipe into a single storage node. In the wetwell properties, choose either "Depth area" or "variable volume" as the "Section" type. You'll then be able to enter the Depth-Area or Depth ratio to volume ratio curve of the wetwell .You could account for the combined volume of the wetwell plus the pipe at each "stage" (vertical increment). Again, I would only consider this if absolutely necessary, but I wanted to mention it as an option.


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

Reply
  • Hello Hamid,

    I'm not familiar with the guideline you mentioned but I'm confident you'll be able to use SewerGEMS to model this system.

    1) When you mention a flow of 0.2 cms, is that a constant flow out of the pump, the peak flow when the pump turns on, or something else? Typically pumps will turn on and off based on the level in the wetwell. So, the smaller the wetwell, the more frequent the pumps will be cycling. Therefore it may help to explain a bit more about the criteria for selecting a wetwell size. Generally speaking, you would enter a reasonable size in the model, compute, assess the results and resize as needed.

    2) When you say "to have", are you asking if there is a way to report the volume? This is not a result field for a conduit but you can view the profile to see the water surface and pipe depth. Again, it would help to provide a bit more information on why this is needed.

    Though it may not be necessary, if the storage pipe is relatively short and you don't need to asses it's capacity or a typical gradually varied flow profile, you could potentially combine the volume of the wetwell with the volume of the pipe into a single storage node. In the wetwell properties, choose either "Depth area" or "variable volume" as the "Section" type. You'll then be able to enter the Depth-Area or Depth ratio to volume ratio curve of the wetwell .You could account for the combined volume of the wetwell plus the pipe at each "stage" (vertical increment). Again, I would only consider this if absolutely necessary, but I wanted to mention it as an option.


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

Children
  • Hi

    1-yes. pump flow rate is constant 0.2 cms.

    2-for the guidline see the following link:.

     

    3-as the following table shows, I need to provide a table to show volume stored in the wetwell and storage pipe for different elevation with interval 0.1m.

    this help me to calculate the switching table (elevation)

    Thanks

    Hamid

  • Hello Hamid,

    In the SewerGEMS solver, pumps operate based on the pump definition and turn on and off based on the wet well elevation. You may be able to adjust the model input such that you get a set flow out from the pump, but there is no way to enter a fixed flow from the pump. I will note that with the SewerCAD solver, you can set the pump up as a variable speed pump, which would allow the pump to operate with a fixed flow.

    For volume reporting, there is no way to report the volume of water in the pipe upstream of the wet well directly. You may be able to try to create a User Data Extension to calculate volume based on other results. Formula-based User Data Extensions are one of the options available. You can find more information at the following link: http://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/creating-formula-based-user-data-extensions

    Otherwise, you may need to find a way of combining the wet well and the pipe, as mentioned in an earlier post, since volume results can be reviewed for a wet well.

    Regards,
    Scott

    Answer Verified By: Hamid.AKbari