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Gully Rating Curve

As I know the Rating curve for the gully is usually can be got from the manufacture. can I generate the rating curve for "Curb Inlet on Grade" by using Bentley FlowMaster? if yes; how that can be done? 

is the rating curve is the relation between the discharge flow and depth of water ponding over the grate? I was not able to find that relation in FlowMaster.

Regards,

Mohamad 

  • With on-grade inlets, only the approach flow vs. captured flow rating curve can be used. Having the ability to enter an approach flow vs. gutter depth curve would not be enough information for on-grade inlets since they need to know how much flow gets captured vs. bypassed. Perhaps the ability to use HEC-22 catalog inlets with the "Bentley Enhanced" SWMM solver is a major benefit you could point out, toward using that solver (rather than the EPA version of the solver)


    Regards,

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

    Answer Verified By: Mohamad Azzam 

  • Hello Jesse,

    As you explained previously; the both intercepted flow and depth are calculated in Flow Master and Bentley SWMM engine, what about generate a rating curve of approach flow (upstream gutter) versus gutter depth, and use that graph (rating curve) with the EPASWMM engine, in this case, can that curve be applied to "On Grade" since will be used with the EPASWMM engine (not Bentley SWMM)?

    Regards,

    Mohamad

  • from what you said for the "On Grade" it can be generated the rating curve "Gutter depth vs captured flow" and can be used for the on garde gully. if I miss understand that; please let me know why can not be used?.

    For on-grade, you can generate a rating curve of approach flow (upstream gutter) versus gutter depth. However, as mentioned in a few earlier posts, with on-grade inlets, both the depth and the intercepted flow are calculated results (with on-grade), so you cannot solve for one, varying the other. This is why the "gutter depth vs. captured flow" rating curve is only applicable to in-sag inlets. See more explanations further up in the thread.


    Regards,

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

  • Thank you Jesse - but I just wanna confirm your statements :

    "Gutter depth vs. captured flow" only applies to in-sag inlets and "flow to inlet vs. flow capture" only applies to on-grade. The reason is explained in my reply from Sunday.
    If you want to see the relationship between approach flow (flow approaching the inlet from the upstream side of the gutter) and gutter depth for an on-grade curb inlet, you could manually vary the Discharge input and observe the "depth" value on the right side (for example you could note the pairs in a table in Excel)

    from what you said for the "On Grade" it can be generated the rating curve "Gutter depth vs captured flow" and can be used for the on-grade gully. if I miss understanding that; please let me know why that can not be used for on Grade?.

    Regards,

    Mohamad

  • 1-Regarding the article that you have mentioned in your reply;  The Solution -in-sag is used the Inlet Type is "Gutter Depth vs. Captured Flow", I need to develop that curve from the FlowMaster, and I guess (correct me if I am wrong) the depth and the captured flow (intercepted flow) would be on the right side in the FlowMaster by varying the Discharge input (on the left side)?

    Yes, in-sag inlets can use a depth vs. captured flow curve but you might think of it the other way around - the "captured flow" is really the approach flow (and also the captured flow since in-sag captures 100%), and the program would look up the gutter depth resulting from a given approach flow (all of which is intercepted). In FlowMaster you would use the curb inlet in-sag worksheet, click the rating curve button and plot depth vs. discharge. I'm not clear on whether the inlets you're trying to model are actually in-sag or on-grade, though.

    2- when you say "Discharge" (where "discharge" means the total approach gutter flow), is that in the Flowmaster in the left side (the input)? jut to confirm, please

    See the screenshot below where I said this in my previous reply - when you click on the "Rating curve" button above the worksheet in FlowMaster, you can choose the two fields to plot. This is where you would select "discharge". "Discharge" in this case refers to the total approach flow. There is indeed also a "discharge" input field in the worksheet form itself, and this does refer to the same flow. Meaning, the "Rating curve" option does the same thing as manually varying the related parameter. For example for an on-grade curb inlet worksheet, plotting Intercepted flow vs discharge is the same as varying the "discharge" input in the worksheet and noting the resulting "intercepted flow" in the results section on the right side.

    3- Can "Gutter Depth vs. Captured Flow" be used for " Solution-on-Grade)? because I noticed that "Flow to Inlet vs. Flow Captured" is used there, and also vice versa can "Flow to Inlet vs. Flow Captured" be used for Solution -In- Sag? and what if I would apply "Gutter Depth vs. Captured Flow" for both (on grade & In Sag)? Please elaborate more if there is any limitation.

    "Gutter depth vs. captured flow" only applies to in-sag inlets and "flow to inlet vs. flow capture" only applies to on-grade. The reason is explained in my reply from Sunday.

    4- If I have a model built in the SewerGEMS with the gullies without rating curve as input, can the model produce those rating curves? i.e. can I generate the rating curves as in the FlowMaster then use them in other models?

    Yes in SewerGEMS you could potentially vary the approach flow and observe the change in results for catalog inlets (for example using the Bentley version of the SWMM solver). You could set up a small model with just one inlet to achieve this. However, it seems to me that it would be easier to just do this in FlowMaster. Once you have the rating curve defined in the inlet catalog, you could export that to an engineering library to then import into other models as needed. Note that the rating curve may depend on parameters such as the road slope that would change, so you might need a different rating curve for each variation of such parameters.


    Regards,

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