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Combining Sewage And Storm Models

I have For  the same network 2 Models one is Storm run using SWMM solver (the flows in the models are catchment areas with time depth graph) and the other is sewage run using GVF-Convex (the flows in the models are sewage flow entered as population and sanitary loading with extreme flow setups for the peak factor calculations), the question is how i combine them keeping the SWMM solver running (sewage flow are peaked and fixed in the manholes) ?!!

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  • Dears Craig & Jesse

    Thanks For Your Fast reply, i appreciated. The Network I am talking about is exiting one (all the data i have for it is only a sewage model with population and unit sanitary loads with solver GVF-Convex ) that carries sewage flow and in the construction phase the contractor connected the storm catch basins to it. so i need to simulate the most worst case that all pipes are fully loaded with the peak sewage flow while the exact storm event is happening. 

    I know that both engines will not run together, for that i tried to convert the peaked flow to a fixed one but i faced a problem that i can't get the peaked flow for each manhole to define it as inflow (wet) fixed flow.

    Thanks a lot in advance

    Diaa Abdelrahman 

  • Hello Diaa,

    Creating separate scenarios is a good approach to test your network.

    The first scenario can be "only the sewer network" with unit sanitary loads and population to determine sanitary flow through the network. You can use the GVF-Convex Solver for this.

    The second scenario (child of the first) can be "sanitary network + the storm flow". In this you can use the additional data of storm inlets using Active Topology Management to add the additional elements (catchments, catch-basins, conduits etc.) and add your storm events and specify them for your catchments. For this you can use the Implicit Solver which can model combined (storm + sewer) systems.

    If you are doing this, the flows in your model would be more realistic as per the storm events specified.

    Alternatively, you can simply add the wet inflow to the manholes based on the peak inflow calculated. What problem are you facing specifying this? You can specify "Fixed" flow type in it. Can you share a snapshot or elaborate on the problem?

    Hope this helps.


    Regards,

    Yashodhan Joshi

  • Dear Yashodhan

    Scenarios means that each flow will be separated and i need both storm and sewage in the pipes. and i need the storm event modeled using the SWMM Solver (As it is the highest accurate Solver) not the Implicit Solver 

    Thanks a lot In Advance 

    Diaa Abdelrahman

  • Hello Diaa,

    Using Scenarios and Alternatives doesn't mean that only one type of inflow will be analyzed (either sanitary or storm). The idea behind creating scenarios and alternatives is to subject the model to different "What If?" conditions (E.g: What if a particular pipe diameter is 600 mm instead of 300 mm which was initially assigned?). With the SWMM Solver you can have both the loadings (sanitary and storm) for your network and the SWMM engine will analyze your network.

    Here is a relevant article which can help you understand the differences in the solvers;

    Differences between solvers: GVF-Convex vs. GVF-Rational vs. Implicit vs. Explicit (SWMM)

    Hope this helps.


    Regards,

    Yashodhan Joshi

  • Dear Yashodhan

    Yes it can analyze both but without taking into consider the peak factor for the flow calculation So the sewage flow is not right in the analysis 

    Regards

    Diaa Abdelrahman

Reply Children
  • Hello Diaa,

    One way to get to this would be to calculate the storm flow and sewage flow over a period of time (E.g: 24 hrs) at every hour. Then add these flow values to get the total flow at a particular manhole. If you know the average hourly / daily sanitary and storm flow values then you can add them and get a value of total "average" flow. Then divide the total "inflows" by the total "average" flow to get the peak factors.

    E.g: If total "average" flow is 250 l/s and total "inflow" is  450 l/s @ 10 AM then the peak factor at that hour is 450 / 250 = 1.8

    Then you can develop a pattern for all the hours with different peak factors.

    Assign this pattern to every manhole and input the total "average" flow value at every manhole. When the engine analyzes the model it will multiply the total "average" inflow with the pattern at every time step and compute your network.

    Hope this helps.


    Regards,

    Yashodhan Joshi

    Answer Verified By: Diaa Arif 

  • Dear Yashodhan

    Thanks a lot I Had It Done With a way like this one 

    Regards,

    Diaa Abdel rahman