RFI - Attachment F - Engineering Report

15 May 2019


31.     In order for the Stormwater 360 device to be considered any further within this proposed
        development, provide:
       a) Independent verification from a suitably qualified and experienced professional to
           confirm that the parameters within the node for the device in MUSIC modelling have
           been tested and verified as per Stormwater Australia (2018) Stormwater Quality
           Improvement Device Evaluation Protocol. Version 1.2 December 2018 to achieve the
           predicted outcomes in the MUSIC model for the development. For the purpose of this
           information request, the suitably qualified and experienced professional must be able to
           demonstrate a minimum 10 years urban stormwater testing and modelling experience
           and be verified in writing by Stormwater Australia as having an appropriate reputation
           and track record within the stormwater industry to provide such independent advice.
       b) A MUSIC model along with plans that demonstrates how a biobasin or other vegetated
           stormwater quality treatment asset could be retrofit into the proposed development to
           achieve the required pollutant reduction targets in the event the proprietary device fails
           to perform under the local conditions.
       c) Agreement that any proprietary device would be considered as a trial only with the view
           to retrofit with a bio retention basin in the event the proprietary device fails to perform as
           required under the local conditions.

Response

30.     Stormwater runoff from the site will be treated to the levels required by the State Planning Policy
        and Noosa Council.

        Runoff quantities from site will be detained so that the peak runoff volume from site in the
        developed scenario is no greater than the pre-development scenario which currently discharges into
        the downstream system.

        The above will ensure that the post-development quality and quantity of runoff discharging into the
        downstream system is consistent with the runoff that currently discharges from site pre-
        development.

31.     The MUSIC models for the assessment have been provided with the Stormwater Management Plan
        which achieves the required targets of pollutant reduction from the State Planning Policy.

32(a) Independent testing and peer review assessment have been completed for the stormfilter devices
      and the MUSIC nodes have been provided by Ocean Protect/Stormwater 360. The data and nodes
      have been reviewed and approved within many South East Queensland Council areas along with
      other councils across Australia.

(b)     MUSIC models of the stormfilter and enviropod devices have been submitted with the revised
        Stormwater Management Plan. It is not proposed to retrofit bioretention basins within the site as
        the development layout and footprint will not allow for large bioretention areas. The mechanical
        treatment devices will be monitored and maintained to ensure the quality treatment of the
        stormwater runoff is compliant with the requirements of the State Planning Policy and Noosa
        Council.

(c)     proposed treatment devices have been assessed under many conditions with independent analysis
        and peer reviews completed. As such it is considered that the treatment devices will function as
        designed within the local condition. The tank has sufficient size to add more filters, if required,
        however this is unlikely. The mechanical devices will be maintained and monitored to ensure the
        runoff is compliant with the requirements of the State Planning Policy and Noosa Council.
Excellence with Economy in Engineering                                                                        4
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