Outlet Structure

  1. Outlet weir

    Provide 90o angle V-notch on both side of launders, weir loading rate14,000 gpd/ft at Qp

  2. Figure 14. (a) Single weir and trough (b) Multiple weirs and troughs with outlet channel at the middle (c) Double weir and trough (d) Multiple weirs and troughs with outlet channel at the side.

    Figure 15. Effluent launders discharging into an outlet channel.

  3. Weir length per tank

    Qp(gal/day): Weir Loading at Qp(gal/day.ft):


    Number of launders: Convey launder width = 2.5 ft, Tank width = 25 ft,

    Weir Length(ft): Tank Width(ft):

    Convey launder width,b(ft):

  4. Number of V-notch weir: At peak flow, width of V-notch = 8"

    Weir Length(ft): Width of V-notch(in):

  5. Discharge q and hydraulic head over one V-notch(1)
    One tank service at Qp=10 mgd,


    Qp(gal/day): Number of V-notch Weir:

    q(ft3/s) h(ft)

    Two tanks service at Qp=10 mgd, or one tank for QA,d=5.0 mgd

    Two tanks service at QA,d=5.0 mgd

    All of which fit the design standard well.

    5.Dimension of launder of V-notch

    Figue 15. Water surface profile in the effluent launder(Dimesions don't apply).

    Width of launders, b=1';
    y1 is depth of the luanders;
    Space between any two launders = 2';
    The flow profile in launders is parabolic curve;
    y2 = the water depth at the end of launder, Select y2 = 2';
    n = Number of V-notch per launder/2;
    l = Width of tank/2;
    q = flowrate per V-notch;
    at Qp,

    y2(ft): q(ft3/s):

    l(ft): Total # of V-notch:

    # of launders: b(ft):


(1). Open Channel Hydraulics, page 352, Richard H. French


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