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Manly Hydraulics Laboratory

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Rainfall Sample Table

The total rainfall in millimeters is shown for each hour. For example 9.0mm indicated at 4:00 means that 9.0mm of rain fell between 4:00 and 4:59 inclusive.
              Hourly Rainfall Totals for KEMPSEY
              ----------------------------------
  Date   21/01/96  22/01/96  23/01/96  24/01/96  25/01/96
  Time    Sunday    Monday    Tuesday  Wednesday Thursday
   0:00       .        1.0       4.0       2.0        .
   1:00       .        1.0       2.0       1.0        .
   2:00       .         .        1.0        .         .
   3:00       .         .         .         .         .
   4:00       .        9.0        .         .         .
   5:00       .        3.0       2.0        .         .
   6:00       .        6.0       1.0        .         .
   7:00       .        3.0       2.0        .         .
   8:00       .        2.0       1.0        .         .
   9:00       .        2.0       9.0        .         .
  10:00       .        2.0      34.0        .         .
  11:00       .        4.0      49.0        .         .
  12:00       .        4.0      28.0        .        3.0
  13:00       .        1.0       6.0       1.0      26.0
  14:00       .        1.0       1.0        .        1.0
  15:00      1.0       2.0       1.0       5.0        .
  16:00       .        1.0       1.0        .        1.0
  17:00       .         .        2.0        .         .
  18:00       .        2.0       3.0        .           The period of data
  19:00       .         .        2.0        .           available is indicated
  20:00      5.0        .        3.0        .           by the '.' markers.
  21:00     13.0        .        1.0        .           The totals for this day
  22:00      4.0       1.0       1.0        .           will be only for the
  23:00       .        2.0       1.0        .           available data.
--------------------------------------------------------
Day Total   23.0      47.0     155.0       9.0      31.0 This is the total for
                                                         each calendar day.

9:00 Total            48.0      35.0     145.0       6.0 The 9:00 total matches
                                                      the conventionally quoted
                                                      rainfall and is the total
                                                      for a 24hr period ending
                                                      at 9:00hrs.

 Grand Total = 265.0   This is the total for all the rain in the marked span.
The table below shows the highest rainfall intensity in mm/hr and the time it occurred for a selected set of durations. If the rain is exceptionally intense then an ARI (Average Recurrence Interval) will be calculated, this is an estimate of how frequently this intensity will occur averaged over a long period of time. For example a rainfall of 53.0mm in 60 minutes can be expected, on average once every 4.3 years.
 
                       Rainfall Intensities above 2.0 mm
                       ---------------------------------
  Maximum in 60 mins  53.0 mm at 11:03 23-01-1996  ( 53.0 mm/Hr ARI = 4.3 yrs)
                                 11:06 23-01-1996
                                 11:07 23-01-1996
  Maximum in  3 hrs  115.0 mm at  9:56 23-01-1996  ( 38.3 mm/Hr ARI = 18 yrs)
                                  9:57 23-01-1996
  Maximum in  6 hrs  128.0 mm at  9:30 23-01-1996  ( 21.3 mm/Hr ARI = 8.1 yrs)
  Maximum in 12 hrs  140.0 mm at  9:30 23-01-1996  ( 11.7 mm/Hr ARI = 3.6 yrs)
  Maximum in 24 hrs  157.0 mm at 23:33 22-01-1996  (  6.5 mm/Hr ARI = 2.3 yrs)
  Maximum in 48 hrs  219.0 mm at 20:42 21-01-1996  (  4.6 mm/Hr ARI = 3.3 yrs)
 
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