2018-05-08 Services & Organisation Committee Agenda

SERVICES & ORGANISATION COMMITTEE MEETING AGENDA                                            8 MAY 2018


9                        SIX MILE CREEK FLOOD STUDY COMPLETION
DOCUMENT INFORM AT ION




Author                           Project Coordinator – Flooding, Coastal and Foreshores, Daniel Wishaw
                                 Infrastructure Services Department

Index                            ECM / Subject / Flood Studies

Attachments                      Nil



EXECUTIVE SUMMARY
Not applicable.

RECOMMENDATION
That Council note the report by the Project Coordinator – Flooding, Coastal and Foreshores to
the Services & Organisation Committee Meeting dated 8 May 2018 outlining the outcomes of the
Six Mile Creek Flood Model and its associated reports.


REPORT
The purpose of this report is to inform Council that the Six Mile Creek Flood Study has been
completed and outline the outcomes from this study.

1.                       Background

The Six Mile Creek is a tributary catchment to the Mary River that collects water from the Noosa
hinterland region encompassing the urban centres of Cooroy, Pomona and Cooran. This
catchment collects overland water run-off from Cooroy Creek, Cooroora Creek, Lake Macdonald
and other minor tributaries and carries it to the north-western border of Noosa Shire, where it
eventually flows into the Mary River. This flood plain is shown in Figure 1, below.

The Lake Macdonald community had previously raised concerns about flooding and the
perceived worsening of flooding after weather events between 2010 and the major flood event of
February 2012. Whilst houses were not flooded during any of the flood events, the concern
centred on the speed that flood waters rose. Speculation included whether development within
the catchment worsened flood impacts downstream in particular the area around Lake
Macdonald. In response to these concerns Council agreed in 2016 to commission a new flood
study for Six Mile Creek.

Noosa Shire’s previous suite of flood models for this region included individual models for Cooroy
Creek, Cooroora Creek, Six Mile Creek as well as relying on inputs from Seqwater with relation
to the Lake Macdonald dam. This approach adequately covered the major urban centres but
lacked consistency and performance, particularly at the borders of the models. These models
also relied on data sets that did not provide the accuracy of modern sets and used modelling
software and techniques that are now out of date.

The Noosa Shire Flood Management Plan identified a need to upgrade the Six Mile Creek flood
model with the expressed aim of ’using the latest flood modelling techniques and standards that
are consistent with other flood models for the region’.




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