2016-07-18 General Committee Meeting - Item 3 - Attachment 1 - Flood Management Plan

5.3.3      Cooroora Creek                                             Following the February 2012 flood, SCC carried out survey
                                                                      to record peak flood levels reached during this event and




                               T
The main watercourse flowing through the town of




                             F
                                                                      these were used in the investigation for model calibration.




                           A
Pomona is Cooroora Creek, with several of its tributaries




                        DR
also flowing through the township.                                    HWMC’s analysis of the rainfall intensities recorded at the
                                                                      Pomona rain gauge for the February 2012 event, estimates
During the evening of February 24, 2012, Pomona was                   that this event was equivalent to approximately a 500 year
subject to a major flood event which impacted homes,                  Average Recurrence Interval (ARI) event.
businesses and infrastructure across the region. During
this event, the township was inundated by flows from                  The design event results of the HWMC flood study model
Cooroora Creek and its various tributaries.                           form the basis of the disaster management mapping for
                                                                      Pomona based upon existing climate conditions.
Following the event, the Sunshine Coast Council engaged
the consulting engineering firm, Projex Partners Pty Ltd,             Recent flood mitigation works have included house/land
to undertake a flood investigation study13. This study                resumptions and removal, earthworks and channelising of
reviewed the history of previous flood studies in the region,         local drainage in and around Rifle Street.
undertook a site inspection and made recommendations
regarding future works. One of these recommendations                  The Cooroora Creek flood study model has been amended
was to complete local and regional flood modelling so as to           to include these works and the resulting inundation extents
provide accurate design flood levels through the township.            for the 1% AEP (future climate) scenario form the basis of
                                                                      the 2016 amendment to the Planning Scheme flood hazard
In 2013, prior to de-amalgamation, the Sunshine Coast                 area.
Council commissioned Hydrology and Water Management
Consulting Pty Ltd (HWMC) to setup and calibrate a                    Additional model runs for minor (2 year ARI), moderate
detailed flood model14 that was suitable for defining                 (10 year ARI) and extreme (500 year ARI) flood events,
flooding characteristics within all significant flow paths            which include the recent mitigation works, are required to
through the Pomona Township and local surrounds.                      update the disaster management map series for Pomona.




12
   Cooroy Mitigation Options Review by Hydrology and Water Management Consulting, December 2013.
13
   Rifle Street, Pomona Drainage Report by Projex Partners for Sunshine Coast Regional Council 2012
14
   Pomona Flood Study by Hydrology and Water Management Consulting, December 2013




                                                                                                 Noosa Council | Flood Management Plan | Page 20