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  • #6665
    ptdcaliguid
    Participant

    Hope you’re having a nice day; I would just like to ask some questions regarding storage area as an upstream boundary (representing reservoir) 🙂

    I defined a reservoir, inline structure and 2 dummy cross sections as I read in one of the posts in hec-ras blog (http://hecrasmodel.blogspot.com/2010/08/how-to-use-storage-area-to-define.html).
    Now what I currently did was to define a reservoir initial elevation in the initial conditions tab. Next I set a boundary condition type of elevation controlled gates at the upstream component of my project. Only a gate boundary condition was set, no hydrograph was set for the reach. Will this be sufficient and will water flow to my reach once water in my reservoir reaches an elevation as stated in my elevation controlled gates settings? Also, is it right in reference selection that I selected “based on specified reference” and selected storage area? The default is upstream WS (which in this case is the dummy x-sections, and which I read in the blog needs setting of an initial stage)?

    Hopefully help can be given 🙂 Have a good day

    #10972
    Anonymous
    Guest

    “Only a gate boundary condition was set, no hydrograph was set for the reach. Will this be sufficient and will water flow to my reach once water in my reservoir reaches an elevation as stated in my elevation controlled gates settings?”

    You do not need a hydrograph for the reach. The upstream end of the reach being directly connected to the storage area is all you need.

    The 1D reach cannot start dry. So either the gates need to have some minimum opening to allow a bit of flow at the beginning, or alternately, you can specify a minimum “pilot flow” on the inline structure editor.

    “Also, is it right in reference selection that I selected “based on specified reference” and selected storage area? The default is upstream WS (which in this case is the dummy x-sections, and which I read in the blog needs setting of an initial stage)?”

    You should specify an initial starting water surface elevation for the cross section immediately upstream of the inline structure. This water surface should be the same as the initial water surface in the storage area.

    Specified reference to the storage area will work fine, but it is not really needed. The water surface in the cross section immediately upstream of the inline structure is going to be [almost exactly] the same as the water surface in the storage area. So leaving it as the default would have also been fine.

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