Response to Further advice - 20220156 Kauri St SWMP · MCU22/0144

 CONCLUSION
This Stormwater Management Report has outlined how the stormwater run-off from the site is to be managed to
comply with the relevant requirements and minimise any adverse impacts to the downstream catchments.

     •    Surface run-off from the proposed development will largely maintain the existing discharge characteristics.
          Peak flow rates in developed conditions will be attenuated to be no worse than existing peak flow rates, and
          run-off will be discharged towards the downstream undeveloped bushland allotments as the lawful point of
          discharge.

     •    Field inlet pits within the driveway will be capture surface run-off with driveway pits to be fitted with pit inserts
          to provide treatment to run-off from the site.

     •    A 30kL rainwater reuse tank will be provided with the maximum possible roof area to drain to the tank. The
          tank is an in ground concrete tank, (Humes Rainvault RV3000-01-00 or equivalent) which is to be connected
          to internal toilets and laundry areas, and external irrigation and wash down fixtures in accordance with the
          sustainable building code.

     •    All run-off from the development will be attenuated using a 54m³ below ground attenuation tank with a
          132mm low flow orifice and overflow weir that has been shown to not increase to existing peak flow
          discharges from the site under developed conditions for all modelled storm events.

     •    During construction, erosion and sediment control measures are to be implemented to minimise potential
          contaminants impacting the downstream receiving environment in line with the objectives of Appendix 2 of
          the SPP. A site-specific erosion and sediment control plan has been developed using best practice
          management principles to achieve these objectives.

     •    The proposed stormwater treatment train has been modelled in MUSIC and found to achieve the stormwater
          improvement quality targets required to comply with the Noosa Plan 2020. The treatment train consists of
          Ecosol litter baskets (200um mesh) or equivalent providing treatment to the driveway areas, and an end of
          line bioretention garden to treat and infiltrate attenuated run-off from the development.

     •    Runoff from the development will be discharged via infiltration from the bioretention garden area into the
          surrounding soils assisting with groundwater replenishment, with larger flow events able to overtop the
          downstream lip of the bioretention area to discharge as sheet flows to minimise flow concentrations and
          protect the downstream environment from erosion and scour.

     •    The proposed stormwater solution is considered to minimise any adverse impacts to the downstream
          environment arising from the stormwater run-off while also meeting the stormwater quality and quantity
          targets required for the development and is therefore a complying solution for the proposed development.




Project number 20220156                                                                                       Page 20 of 28
File RECOR Stormwater Management Report - 20220156.docx, 2023-01-13 Revision 2

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