Response to Info Request - Attachment 4b - Engineering Report Part 2 MCU18-0015 & RAL18-0001 · MCU18/0015

Peak Discharge Calculations
Reference ‐ Chapter 4 QUDM.




Job Name.                Attunga Heights             CATCHMENT INFORMATION
Job No.                  C5756                     SITE LOCATION                   Noosa Shire
Date                     23/05/2018                IFD INFORMATION                   Noosa IFD
Designed                 MVC                       10% AEP 60min                       74.8
Checked                  JW



                   TIME OF CONCENTRATION                     TIME OF CONCENTRATION CONTINUED                                       COEFFICIENT OF RUNOFF
                                                                                                                       Sub‐Catchment Area (Ha) Fraction Impervious (%)        Runoff Coefficients




                                                                CHANNEL FLOW‐3
                         Std Inlet Time     0.0                                  Flow Length (m)    160.0   CMT No.     Existing     Developed        Existing    Developed   Existing      Developed
                                                                                 Fall (m)           17.0      1         25.133        25.133             10          10         0.72          0.72
                                                                                 Flow Time (min)     1.0      2          3.506         3.506             60          60         0.82          0.82
      SHEET FLOW




                         Slope (%)         27.0                                  Multiplier ∆         3       3          1.802         1.802              5          20         0.71          0.74
                         Flow Length (m)   50.0                                  Flow Time (min)     3.0      4
                         Horton's 'n'      0.035                                                              5
                         Flow Time (min)    7.1                                                              Total      30.441        30.441            15           16        0.73           0.732
                                                                CHANNEL FLOW‐4

                                                                                 Flow Length (m)    730.0
                                                                                 Fall (m)           50.0                                     PEAK DISCHARGE CALCULATIONS
      CHANNEL FLOW‐1




                         Flow Length (m)   130.0                                 Flow Time (min)     2.0                  Rainfall (mm/hr)            Coefficient of Runoff   Peak Discharge (m³/s)
                         Fall (m)          16.0                                  Multiplier ∆         3       AEP       Existing     Developed        Existing    Developed   Existing      Developed   Increase (%)
                         Flow Time (min)    0.8                                  Flow Time (min)     6.0      63%        77.2           77.2           0.58         0.59       3.81           3.82          0.3
                         Multiplier ∆        3                                                                50%        87.3           87.3           0.60         0.60       4.45           4.46          0.3
                         Flow Time (min)    2.3                                                               20%        118            118            0.69         0.70       6.92           6.94          0.3
                                                                                 Flow Length (m)     0.0      10%        137            137            0.73         0.73       8.46           8.48          0.3
                                                                                 Fall (m)            0.0       5%        156            156            0.77         0.77       10.11          10.14         0.3
                                                                PIPE FLOW
      CHANNEL FLOW‐2




                         Flow Length (m)   60.0                                  Flow Time (min)     0.0       2%        179            179            0.84         0.84       12.71          12.74         0.3
                         Fall (m)          16.0                                  Multiplier ∆         1        1%        196            196            0.876        0.878      14.52          14.56         0.3
                         Flow Time (min)    0.2                                  Flow Time (min)     0.0
                         Multiplier ∆        3                                                                                            MANNING'S CALCULATIONS
                         Flow Time (min)    0.6                                                             Scenario     Area        Perimeter    Radius        'n'            Slope        Velocity    Discharge
                                                                                  Total TOC (min)   19.0      Pre        10.23         12.63      0.810        0.15             6.0          1.419        14.52
                                                                                                              Post       10.25         12.64      0.811        0.15             6.0          1.420        14.56