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

1. Executive Summary
A flood study of the Six Mile Creek catchment was conducted in 2017 to combine past studies of
Cooroy, Six Mile Creek and Pomona catchments into one continuous flood study. By reviewing the
flood studies in the Six Mile Creek catchment we are able to apply the latest in modelling
techniques, data collection and computational ability to continually refine and improve our
knowledge of the flood plain. The Six Mile Creek flood study upgrade was conducted by WMA
Water Pty Ltd in conjunction with HydraLogic, acting as an independent review, as well as Noosa
Council.

This sub-report of the Six Mile Creek Flood Study is an investigation into concerns raised by the
Lake McDonald community with regard to flooding in their area. The investigation looks to address
concerns specifically raised by the community either through the multiple community reference
group forums Noosa Council has conducted, site visits conducted jointly by Noosa Council, WMA
Water and HydraLogic or by communication directly with the residents.

This report has also investigated several possible mitigation solutions that were jointly proposed
with the community reference group to mitigate the effects of flooding within the Lake McDonald
community. The investigations concluded that none of the possible mitigation solutions would be
viable as they offered little benefit to the community and had large costs either financially,
environmentally and/or had an adverse effect on other areas of the community.

The report does note positively that Noosa Council has invested strongly in its understanding of
this catchment through this flood study and also by installing five new flood monitoring gauges
within the catchment, three of which are upstream and useful for this community. These gauges
will allow the community to monitor rainfall as it occurs as well as rising water levels within the Six
Mile catchment before it impacts members of this community.

Members of the Lake McDonald community have been provided with instructions on how to access
this information through the Bureau of Meteorology website and have been shown where to find
other resources relating to flood awareness on the Noosa Council website.

This report concludes a major body of work in consulting with the community and understanding
the flooding within Six Mile Creek, but also specifically around the Lake McDonald community;
however, this does not represent the end of the this work. Noosa Council will now be able use this
investigation to inform future work including flood risk assessments, catchment wide mitigation
options, alert systems, disaster management mapping and disaster response.




Lake McDonald Flooding Community Reference Group Report                                          Page 3