Welcome to the RAS Solution Forums HEC-RAS Help HEC-RAS Data Input Format (River Flow and Sediment Transport)

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  • #7277
    jmrsalonga
    Participant

    Greetings, everyone! 🙂

    I am currently taking Water Resources Management for BS Civil Engineering program, and we are taught to use HEC-RAS to run river flow simulations for various river set-ups and characteristics (steady, unsteady, etc). The software is pretty much straightforward and I am having fun learning how to use all of its tools.

    However, one tricky part is analyzing data inputs. Our professor gave us some clear instructions for the first few river flow problems, but I am clueless about this latest one. I assume this one is taken out of some file type that the software can read directly. Unfortunately, this is all I have and I just need to know what the symbols and numbers mean. Can someone here help me out to identify what these figures mean?

    River Flow and Sediment Transport Problem with HEC-RAS

    Cross Section Data

    X1 M6.0 8 100 145 5280 5280 5280
    GR 33 0 15 10 13 100 3 105 3 140
    GR 13 145 15 240 33 250
    *
    X1 M5.0 8 100 145 5280 5280 5280
    GR 32.5 0 14.5 10 12.5 100 2.5 105 2.5 140
    GR 12.5 145 14.5 240 32.5 250
    *
    X1 M4.0 8 100 145 5280 5280 5280
    GR 32 0 14 10 12 100 2 105 2 140
    GR 12 145 14 240 32 250
    *
    X1 M2.0 8 100 145 10560 10560 10560
    GR 30 0 12 10 10 100 0 105 0 140
    GR 10 145 12 240 30 250
    *
    X1 M1.0 8 100 145 5280 5280 5280
    GR 29.5 0 11.5 10 9.5 100 0.5 105 0.5 140
    GR 9.5 145 11.5 240 29.5 250
    *
    X1 M0.0 8 100 145 10560 10560 10560
    HY R4 RM 0.0
    GR 28. 0 10. 10 8.0 100 -1.0 105 -1.0 140
    GR 8,0 145 10. 240 28. 250
    *
    * Last cross section copy from previous section with elevations lowered 2.0 feet.
    X1 MD.0
    *

    Manning’s n: Main Channel = 0.03, Floodplains = 0.08

    Use Toffaleti’s Transport Equation
    Materials Transported: FS, MS, CS, VCS, VFG, FG, MG, CG
    2 3 4 5 6 7 8 9

    Sediment Discharge Rating Curve (Qs= tons per day, Q=cfs)
    [applied to both U/S of RCH1 and RCH3]
    Q 100 1000 10000 100000
    Qs:
    FS 2.75 218.75 32160 181250
    MS 2.8 198.75 22160 101250
    CS 2.6 78.75 10160 151250
    VCS 2.568 56.75 6160 91250
    VFG 0.55 4.7 47 500
    FG 0.25 2.2 20 210
    MG 0.15 3.5 78 2200
    CG 0.15 3.5 78 2200

    Bed Material Gradation
    FS MS CS VCS VFG FG MG CG XSs
    RCH1 10 20 20 20 14 8 5 3 1-2
    RCH2 13 32 30 12 7 4 0 2 3
    RCH3 18 23 14 13 14 10 8 0 4-5
    RCH4 10 20 20 20 17 8 5 0 6-7

    U/S Inflow: 5000, 15000, 4500 cfs for period for first 720 ,then 1440 and finally 1440 hours

    D/S Water Surface: Assume uniform flow with reasonable friction slope based on Manning’s BC

    For the second part, I already distinguished the FS, MS, CS, and VCS as the soil texture classifications, but I have no idea what the other numbers mean.

    I’d really appreciate anyone who can guide me out here. Once I know what these values stand for, I can easily proceed with running the simulation. Thank you so much in advance, and I hope to learn more about the experts from here! 🙂

    #12195
    Anonymous
    Guest

    That looks like a HEC6 text file. HEC6 is an old sediment transport program that was replaced by HECRAS.

    I’m a little surprised your instructor is trying to make you deal with that. You might see if you can find a HEC6 manual online somewhere.

    *
    X1 M5.0 8 100 145 5280 5280 5280
    GR 32.5 0 14.5 10 12.5 100 2.5 105 2.5 140
    GR 12.5 145 14.5 240 32.5 250
    *

    The ‘X1’ stands for cross section. So that is cross section M5.0. I don’t know what the ‘8’ is. The ‘100’ and ‘145’ are probably left and right channel station. The 5280 are the lengths of the overbank and the channel. The next two lines are the station/elevation data for the cross section.

    Sediment Discharge Rating Curve (Qs= tons per day, Q=cfs)
    [applied to both U/S of RCH1 and RCH3]
    Q 100 1000 10000 100000
    Qs:
    FS 2.75 218.75 32160 181250
    MS 2.8 198.75 22160 101250
    CS 2.6 78.75 10160 151250

    This looks like the upstream sediment boundary. So, for instance, if the flow was ‘1000’ cfs there would be 218.75 tons/day of Fine Sand.

    Good luck.

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