stormwater mgJ00300R1V1_25_Kauri_St_Cooroy_Complete · MCU18/0165

25 Kauri St Cooroy




Table 4-2 Pervious Area Initial Loss (mm)

     Duration          50% AEP              10% AEP             1% AEP
       5 min              29.5                25.3                22.2
      10 min              29.5                25.3                22.2
      15 min              29.5                25.3                22.2
      20 min              29.5                25.3                22.2
      25 min              29.5                25.3                22.2
      30 min              29.5                25.3                22.2
      45 min              29.5                25.3                22.2
      1 hour              29.5                25.3                22.2
     1.50 hour            29.2                19.7                18.5
      2 hours             23.8                13.9                11.8
      3 hours              15                  0.7                 0


BoM’s ARR 2016 Rainfall IFD data has been used for this investigation. Design rainfall depths
are shown on Table 4-3.

Table 4-3 Design Rainfall Depths (mm)

     Duration          50% AEP              10% AEP             1% AEP
       5 min              11.3                17.9                26.3
       10 min             18.3                28.7                41.2
       15 min             23.2                36.4                 52
       20 min              27                 42.3                60.8
       25 min             30.1                47.3                68.3
       30 min             32.7                51.5                74.9
       45 min             38.9                61.9                91.5
       1 hour             43.8                70.2                105
      1.5 hour            51.4                83.7                128
       2 hour             57.6                94.8                147
       3 hour             67.7                113                 178
      4.5 hour            79.8                136                 217
       6 hour             89.9                156                 251
       9 hour             106                 188                 306
      12 hour             119                 214                 353
      18 hour             140                 256                 428
      24 hour             156                 289                 489


The adopted ensemble hydrograph for each AEP event is shown on Image 4-1. Peak flows and
the associated critical storm duration are also labelled. These hydrographs represent the design
storm runoff from the full existing site.

Peak site runoff for the 1% AEP design event is predicted to be 0.23m3/s.




J00300R1V1                                                                                   5