RFI - 20210153 Maple St SWMP

     2. Sediment fencing along downstream of the work areas within the site to prevent sediment
        from leaving the construction area.

     3. A shakedown area is to be installed at the construction entry/exit to the proposed
        development area to minimise sediment being transported to and from the site.

     4. Ensuring any stockpiles and construction materials are contained using sediment fencing
        downstream of these areas.

     5. Downstream pits within the property to be protected through filter socks or similar.

     6. Diversion of upstream catchments around any exposed areas through the use of turfed catch
        drains or similar.

Discharges from the site during the construction phase are to be controlled to ensure flows into the
verge are no resulting in nuisance impacts or hazards to pedestrian traffic. All run-off is to be
discharged within the site at grade to match external ground levels, passing through a rock energy
dissipating outlet that will disperse flow concentrations and reduce risk of erosion or scour to the
downstream verge.


     4.2. Operational Phase
The development is to comply with the Noosa Council Water Quality and Drainage Code, AO6.2
which states:

“All stormwater runoff is treated to achieve maximum removal of nutrients, gross pollutants and
suspended solids as determined by cost to efficiency ratios. (e.g., bioretention basins must be sized
to achieve at least 80% reduction in total suspended solids, 60% reduction in total phosphorous, 45%
reduction in total nitrogen and 90% reduction in gross pollutants >5mm).”

It is proposed that the following measures to be implemented will provide the required level of
stormwater quality improvement to minimise impacts to the downstream network:

     •    First-flush divertors will be installed for roof-water drainage to divert initial run-off capture
          to irrigation of the vegetated areas on site.
     •    Roof run-off will be captured for reuse in a 50kL rainwater storage tank, supplying non-
          potable internal and external demands throughout the site.
     •    An OSD area providing 50kL of detention storage will mitigate overflows from roof run-off
          exceeding the capacity of the reuse tanks to ensure critical storm peak flows from the
          development do not exceed present levels.
     •    A 20m² bioretention area will be used to treat stormwater run-off from the newly developed
          area prior to discharge from the site.



          4.2.1 MUSIC Modelling
The proposed development and the above treatment train have been modelled in MUSIC (Model
for Urban Stormwater Improvement Conceptualisation) software in accordance with the Water by
Design MUSIC Guidelines 2018.

The climatic data has been modelled using the rainfall and PET data at station 40059 (Cooroy
Composite) in 6-minute timesteps. The rainfall run-off parameters have been set as defined for the
Southeast Queensland region, shown below in Figure 4.2 - Rainfall run-off parameters for SEQ.




Project number 20210153
File RECOR Preliminary Stormwater Management Report - 20210153.docx, 2022-03-31                                 Page 16 of 27
Revision 1

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