PondMaker

Hello,

In attempting to use Pondmakers guide, I got stuck on step 4 where it does the outlet design. I noticed for some reason, my target curve rating just would not show up. There is nothing to go of of from my target curve rating and it is making it so that I won't be able to design my outlet structure.

Using PondMaker to Design a pond in under five minutes - YouTube

In this video you can see at the 3:00 mark they show that there is a target rating curve in turquoise that allows the user to get their composite structure to closely align with once designed.

If there is any solution to this let me know.

Thanks

  • I have now added this clarification in the PondMaker wiki article.


    Regards,

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

  • Shayaan,

    The Target Rating curve represents the curve that you would need to closely match to the designed outlet rating curve, to get close to the target predevelopment flow rates. It is a line, so it needs to connect between at least two points. Those points are the pairs of target predevelopment peak flow and corresponding estimated water surface elevation. With only one storm event entered, there would be only one pair of target flow and elevation and the program is designed to draw a line between multiple points instead of just showing a single point (dot) in space.

    Typically you would design a pond for multiple return events, for example lower events like 10 and 25 year to align with lower outlet components like orifices/culverts and risers, then a higher return event like 100 year, to design for the emergency overflow weir for example. I do not recall seeing PondMaker used before with just one return event.

    We will seek to document this more clearly in the PondMaker wiki article.


    Regards,

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

  • So I guess I'm not completely understanding what this target rating curve represents now. I had thought that the target rating curve represents the outflow you are trying to meet depending on the predevelopment flows based on a single storm event? 

    Just curious why it is needed for two storm events to be needed in order for the curve to show?

  • Hello,

    One of my colleagues looked into this as well. The reason that there is no target rating curve is that there is only on scenario being used in PondMaker. If you add storm data for the 25 and/or 100 year scenarios and include those in PondMaker, the target rating curve will be displayed. 

    Regards,

    Scott

  • Hello Shayaan,

    I don't see the target rating curve either, but there appear to be results in the table to work off in designing the pond and pond outlet structure.

    That said, there are some possible setup issues. First, the pre-development scenario includes the pond. Typically, the pre-development scenario will be how the system looks before the catchment parameters are changed when it is developed. In SewerGEMS and CivilStorm, the would require a setup similar to what you see in the screenshot below.

    The predevelopment catchment is routed through a different outflow node to the outfall. This will give you an accurate target flow and volume at the outfall. You already have the scenarios and alternatives set up for the model. It would simply be a matter of adding the necessary elements for the predevelopment scenario, setting the new Outflow Node for the predevelopment catchment, and making elements inactive. Notice that the pond, pond outlet structure, and conduit are inactive in the predevelopment scenario. In the post-development scenario, it is reversed. The transition and conduit are inactive. You can find more on active topology there: Active Topology Management.

    There are some other issues with the PondMaker setup as well. First, the pond elevation-area curve in PondMaker is different from the pond you have in the model. It includes different pond elevations and areas. Make sure the pond elevation and area information are accurate. 

    This also relates to the outlet structure input. In PondMaker, the minimum pond elevation is 103.5 ft and in the model, the minimum pond elevation is 100 ft. The composite outlet structure is using the 100 ft minimum headwater elevation, so there is a mismatch between the pond being designed and the outlet structure. The riser in the composite outlet structure as an elevation of 102 ft, which is below the pond being designed, where the elevation is 103.5 ft. 

    One other issue with the composite outlet structure is that the riser has a Downstream ID set to the weir. This means that flow from the riser is directed to the weir. Since the weir has a higher elevation, flow would not start coming from the pond until the water reaches that level. I would recommend setting the riser's Downstream ID to "Tailwater."

    As mention, you should still be able to design the pond and pond outlet structure without necessarily seeing the Target Rating Curve. The flow and volume data is still reported, as well as if it passes or fails based on the parameters you set in PondMaker. I would recommend reviewing your model and adjusting the setup or making sure the setup is accurate.

    Regards,

    Scott

    Answer Verified By: Shayaan Hassan