2018-05-14 GC Agenda Attachment 1 to Item 6 Lake MacDonald Dr Community Reference Group Investigations Report

Figure 2: Historical Rainfall Records – Eumundi



4.1      February 2012 Flood Event
The February 2012 flood event is the most significant flood for this catchment in recent records.
This event was characterised by a very intense and localised storm cell where 182 mm of rainfall
was recorded at the Cooroy rainfall station in 1 hour between 9:50 pm and 10:45pm on the 24th
February. Total rainfall volume for this relatively short event at the Cooroy rainfall station was
332mm.

Compared to other long term rainfall records the statistical likelihood of an event of this intensity
occurring is approximately 0.2% in any given year which is statistically equivalent to approximately
once every 500 years.

The new flood study model has been calibrated to reproduce the February 2012 event based upon
the recorded rainfall records and available peak water levels throughout the catchment.
The calibration process was also informed by observations and experiences provided by CRG
stakeholders and the model results generally reflect these observations. These observations
included the rapid rate of rise in flood water and the extent of the inundation at various locations in
the vicinity of Highland Drive.

The upgraded flood model has been deemed to have been sufficiently calibrated to peak flood
records throughout the catchment and observations of the CRG stakeholders.




Lake McDonald Flooding Community Reference Group Report                                         Page 8