MCU14-0039 Flood report and flood man Plan rev August 2015

Como Glasshouse P/L C/‐ Martoo Consulting P/L
Flood Impact Assessment – 305 Lake McDonald Drive Cooroy

Following a flood event, it is possible that plastic sheeting and planting material may be deposited in
the creek. Preventative measures such as removal of sheeting or raising the sides of the greenhouse
structure prior to the arrival of floodwaters should be implemented. Similarly, an extensive inspection
of the creek will be undertaken following a flood event to ensure the removal of any plastic sheeting
and planting materials.

3.5                Flood Emergency Management Strategy
3.5.1              Method
Given that the site is only occupied in daylight hours from Monday to Saturday, the best course of
action to minimise site flood risk is to completely evacuate the site to higher ground at the PGH Bricks
and Pavers site located adjacent to the primary site access location. An alternative for evacuation to
higher ground is also available via the secondary access location.
Like any planning for a potentially high risk event such as fire, earthquakes, etc. a FMP will require the
following key requirements to be met to ensure the FMP is safe and effective: ‐
a)      Training
Education and Awareness is mandatory for all site personnel to ensure the effective implementation
of this FMP. It will be important to distinguish regional flooding (long duration rainfall causing Six Mile
Creek to rise moderately) from severe storms of short burst where the site may be inundated for short
durations until the local stormwater runoff is able to discharge off the site. It may be more dangerous
to be outside during a short duration storm event given wind and rain‐driven hazards that can occur.
b)      Site Refuge and Evacuation
For short duration storms, staying on the site and under cover is generally the safest option.
For long duration intense rainfall, the Flood Management Plan outlined in this section provides
guidance on leaving the site and securing equipment and chemicals stored on site.
Government agencies broadcasting flood warning messages will be used to assist in management of
the site flood risks and providing guidance on whether the rainfall is localised or regional. Site flood
triggers (as outlined below) will also provide site specific flood information which will inform this FMP.
3.5.2              Flood Triggers
There are no water level gauging stations in close proximity to the site. Given the short response time
of Six Mile Creek (i.e. understood to be less than 6 hours), evacuation procedures will be based on
visual inspection of water levels in Six Mile Creek at one (1) location at the site. This location is
identified as Location 1 in Appendix C. The hydraulic model results indicate that, during a significant
flood event, once water breaches the top of the existing creek embankment at Location 1, there is up
to two (2) hours until egress of the local site access road linking to the primary access to Lake
Macdonald Drive is compromised. Even if the rate of rise is significant at Location 1, and the available
warning is reduced, there is still adequate time available based on the flood modelling for on‐site
personnel to safely and immediately evacuate the site.
Accordingly, it is recommended that a water level gauge be installed in Six Mile Creek at Location 1 as
illustrated in Appendix C. This site based gauge is to be continually monitored during periods of heavy
rainfall. Once water levels at Location 1 reach a height of 92.0m AHD, the immediate evacuation of
the site must be undertaken. This gauge could also be connected to a water level trigger and solar
panel array to provide an audible warning for immediate commencement of site evacuation.
Automation of this gauge should be considered by the site manager, and especially if the Location 1 is
unable to provide visual reference for the site operations area.


3917‐01 / R01 v02 ‐ 31/08/2015                                                                          11