Response to Information Request · OPW11/0196

                                                       TATE PROFESSIONAL ENGINEERS PTY LTD
                                                                                ABN 28 086 262 035   TOTE
    Rational Method

     For a 1 year ARI storm in Noosa:

    5I1     = 128mm / hr

    soi,o
             = 72m / hr

    From Table 4.05.3(a) of QUDM:

    C10     = 0.76
    Fy      = 0.80

    5Qy = 0.76 x 0.80 x 128mm / hr x 789m2

            = 0.017m3/sec


    Swale Capacity - Mannings

    For Swale 2 flowing full:

    A = 0.3x1.0 = 0.3m2
    P = 2 x 0.3 + 1.0 = 1.6m
    R = A/P = 0.188m
    n   = 0.04 (medium grass)
    s   = 0.005
    V = R2'3 S112 /n = 0.1882'3 x 0.005'2 /0.04
                     = 0.58m / sec

    Q = V.A = 0.58m / sec x 0.3m2
              = 0.174m3 / sec >>5Qj

    This proposed swale 2 is adequate to convey 1 year ARI flows and hence 3 month ARI flows.

    3.      Please confirm whether both swales on the property are intended to be located at the
            same RL's or otherwise provide design detail including finish levels for both swales.

    Drawing D02B has been amended to include details of swale 2 as requested. Note carefully that
    the existing boulder retaining wall was designed and inspected by Tate Professional Engineers
    and we hereby certify that it's structural stability and adequacy will not be compromised by
    construction of adjacent swales and RIP's as detailed.




    4.      Demonstrate that there will not be an increase in runoff in events that exceed the
            design capacity of the swales. Appropriate detention must be demonstrated where
            required.

    All rainwater incident on the proposed development, up to 100 year ARI events is to be infiltrated
    on site via Rapid Infiltration Pits as demonstrated in the application. As such there will be no
    runoff from the site for events up to 100 year ARI and no increase in runoff from the site for
    events up to 100 year ARI, satisfying the requirements of QUDM and Condition 49.




S3000/11/L8/Response to Information Request - Sunshine Coast Regional Council
SH/cw