8. APP G. Engineering RFI Response

       Item 27 – Bioretention Basin
       Confirmed. The stormwater management strategy has been amended to provide separate bioretention
       and retention systems. This removes the need for retaining walls, as batters will be provided near the
       bioretention areas. The design of this system is in accordance with the Water by Design Technical
       Design Guidelines. The revised basin location also allows for maintenance access from the paved areas
       of the development, refer to the amended drawings for further detail.

       Item 28 – Water Tanks
       Confirmed. The development now proposes to include an underground water tank for detention
       purposes on site, in addition to the bioretention basin for stormwater quality treatment. Part of the
       detention tank volume is dedicated to stormwater retention and harvesting. By making provision for an
       onsite stormwater retention/ harvesting, the proposed design complies with Outcome 3 of the Waster
       Sensitive Design Code of the Noosa Plan. Additionally, detailed sections of the stormwater system have
       been added to clarify its function.

       Item 29 – Detention Storage
       The design has been amended to provide for separate bioretention and detention systems. The outlet
       arrangement has also been amended to reflect the change in stormwater strategy on site. Please refer
       to SK1305 and SK1306 for further information.

       Item 30 – Flood Detention
       The design has been amended to provide for separate bioretention and detention systems. This allows
       for sufficient depth of the underdrainage to drain from the bioretention basin into the detention tank. The
       three existing legal points of discharge are being maintained in the developed state. Overland flow and
       surcharge from the pit in north of will be directed to the east.

       Details of the drainage system are provided in SK1305 and SK1306.

       Item 31 – Stormwater Drainage
       The current flow regime of stormwater leaving the site will be maintained in the developed state. All
       three legal points of discharge and overland flow paths will be maintained. With regards to stormwater
       at the bioretention basin and detention tank, no overland flow will be directed towards Walter Hay Drive,
       rather it will surcharge from the existing pit on Lot 31 SP170751 and flow to the east.

       Item 32 – Stormwater Drainage
       SK01305 and SK01306 have been amended to show the field survey of the existing stormwater
       drainage system of the proposed development site. It can be seen that the secondary overland flowpaths
       to Eumundi Noosa Road, Lionel Donovan Drive and east of Lot 31 SP170751 will be maintained in the
       developed state.

       Item 33 – Erosion and Sediment Control (ES&C)
       Erosion and sediment control measures will be included in the construction phase of the development,
       and will be detailed in the Operational Works application drawings. Additionally, Hyder will be using the
       bio-basin area in Lot 31SP170751 as a temporary sediment basin during construction, prior to
       placement of sand filter. With regards to the months of construction identified, the exact start date is as-
       yet unknown. The checklist has been revised to reflect 2 points for the construction month, which
       provides greater flexibility for the project. Hyder expects that a detailed ES&C plan will be conditioned
       in the development permit and provided at the time of the operational works application.




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