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

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      Flood Studies




Noosa Council has a suite of flood studies which cover                    5.1.1       Noosa River Flood Study
most of the major waterways and floodplains of the region.
The age and origin of these studies varies from catchment                 The first major flood study of the Noosa River was
to catchment however, prior to de-amalgamation the                        completed in 1995 by consultants John Wilson and Partners
                                                                          (JWP)3. The model is comprised of two separate modelling
Sunshine Coast Council had attempted to standardise
                                                                          components. The first being the hydrology model which
some of the model approaches and generate a suite of
                                                                          determines the amount of runoff generated from rainfall
relatively consistent flood studies across the region.
                                                                          falling on contributing catchments; and the second being
                                                                          the hydraulic model which determines the depth, extent and
The following sub-sections present a brief summary of the
                                                                          speed of the runoff (i.e. the flood waters) as they flow along
flood studies available for each of the major catchments
                                                                          the main waterway corridor(s) of the river. The original
and waterways of the Shire. Further details and documents
                                                                          flood study utilised a combination of RAFTS hydrological
associated with each of the studies discussed here can be
                                                                          modelling and one dimensional (1D) MIKE11 hydraulic
found via the Council’s Flood Information Repository                      modelling. 1D modelling refers to the basic “spine and rib”
established as part of this Plan.                                         structure of the model. The spine being the waterway and
                                                                          the ribs being linear cross sections of the terrain and river
The community can assess information from this repository
                                                                          bed profile spaced along the River.
through an online flood search request.
                                                                          Calibration of the original flood study models was
5.1 Noosa River Catchment Flood                                           primarily limited to a single historical event recorded in
    Studies                                                               February 1992. The event was considered a major flood
                                                                          event with a reasonable selection of recorded flood levels
The Noosa River catchment covers approximately 106,000                    for calibration. Another major flood event had occurred
hectares and extends from the Cooloola National Park in                   in 1968 however records for this event were sparse and
the north to the coastal township of Peregian in the south.               in some cases determined to have been unreliable and
                                                                          inconsistent with other relative historical records. Other
The catchment accounts for approximately half of Noosa                    significant historical events which occurred within the
Council local government area.                                            catchment and river system in the early to mid 1970’s were
                                                                          determined to have been too minor for calibration.



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    Noosa River Flood Study Noosa River Flood Study, by John Wilson & Partners Pty Ltd and Lawson & Treloar Pty Ltd, May 1995.




                                                                                            Noosa Council | Flood Management Plan | Page 15