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

There are also ancillary risks to people, property, environment and operations that can occur
coincident with flooding, including: ‐
    c) Storm damage of the premises and property. These can result in torn roofs, shattered
        windows, damage from fallen trees, etc.
    d) Loss of power.
    e) Contaminated water supplies or sewage surcharge.
    f) Constrained access/egress through intense rainfall, winds, fallen trees, debris, fallen
        powerlines and surcharged manholes (displaced manhole covers) etc.
Items a) and b) are the principal causes of risk that are managed as part of this FMP.
Items c) to f) may or may not occur coincident with flooding and can occur to any property regardless
of whether they are within a floodplain. However, the FMP does also give due consideration to these
items which are risks that can hinder the proper execution of the FMP.

3.3.2             Flooding at the Site
As indicated in the sections above, the site is located on low‐lying land and is almost completely
inundated during the 10% AEP and 1% AEP flood events. Flood depths during the 1% AEP event are
in excess of 1.8m in isolated areas of the site. Given the flood depths at the site, and in associated
flood velocities that occur as estimated using the hydraulic modelling, this presents a serious risk to
both people, property and the environment at the site.
3.3.3             Access to Site
Current access to the site is via an entry point situated on Lake McDonald Drive as illustrated in Figure
1 previously. As part of the development, an alternative site access point has been secured to Lake
Macdonald Drive to the south and through the existing PGH Bricks and Pavers site located on Lot 2
SP108094 via an access easement. This new access will represent the primary access point to the site,
with the current access used as an alternative and secondary access location.
Both site entrances lead to an internal access road which traverses a small creek anabranch of Six Mile
Creek via existing low‐level crossings. As outlined in the flood modelling results, Lake McDonald Drive
in the vicinity of the site is generally immune from inundation during the 1% AEP flood event.
However, the internal access roads are susceptible to inundation during more frequent events and
will restrict site egress during times of flooding.

3.4               Management of Hazardous Materials and Chemicals
Potentially hazardous materials and chemicals are stored on site. In the event of a severe flood at the
site, all potential sources of contamination including hazardous materials and chemicals, as well as
waste bins and skips can either be: ‐
         Removed from the site and taken to an area that is located well above the 1% AEP flood event.
          This could include the area of the site associated with the secondary site access which is flood
          free; or
         Placed on a flood resilient building or enclose and raised to above the 1% AEP flood level.
It is considered preferable that the latter option is employed as this minimises the potential for
hazardous materials to be inadvertently left at the site during flood events or associated logistical
issues with physically removing such materials to the flood free area of the site during times of
flooding. Hazardous materials are to be stored in the buildings on site at a height above the 1% AEP
flood level (typically higher than 1.5 m above ground level) or in the vicinity of the existing site
entrance area providing security measures are in place.


3917‐01 / R01 v02 ‐ 31/08/2015                                                                         10