Appendix 3 - Stormwater quality management plan

Stormwater Quality Management Plan – Commercial Development at Weyba Road, Noosaville         CC-3668



2.3.3.    Effectiveness in Pollution Reduction
The water quality model was set up with the incorporation of the above devices to reduce pollutant
export to WQO levels. Table 2.5 below indicates the predicted pollutant reductions as calculated by
MUSIC.

                            Table 2.5 – Treatment Train Effectiveness

                         Pollutant (kg/yr)                   % Load Reduction

                Total Suspended Solids (TSS)                       89.8%

                Total Phosphorus (TP)                              65.8%

                Total Nitrogen (TN)                                61.3%

                Gross Pollutants >5mm (GP)                          100%



The MUSIC modelling results shown above indicate that the treatment train will adequately treat TSS,
TP and TN in accordance with the targets required under the water quality objectives stated in Section
2.3.1 of this report.

2.3.4.    Hydrocarbons
Hydrocarbons are not a target pollutant in regards to achieving the WQO’s as specified by the SPP.
Given the nature of the development proposal it is however considered prudent to identify how
hydrocarbons will be captured on-site and appropriately disposed of. As there is a very short and
direct passage of drainage from the site to Weyba Creek and the Noosa River it is proposed to drain
the bowser areas under the canopies to trade-waste via a hydrocarbon separator such as a Clereflo
Forecourt full retention separator, or approved equivalent. This device will provide full capture of
wash-down and drainage from the bowser areas, hydrocarbons are retained in the device for
disposal whilst remaining water is discharged to the sewer system via a trade-waste permit.

2.3.5.    Maintenance
An Operational Management and Maintenance Manual has been produced for the water tank and bio-
retention devices and is attached to this document as Appendix C. The manual outlines maintenance
responsibilities and requirements for the future operators of the water quality treatment devices. The
maintenance of the proprietary hydrocarbon separator should be in strict accordance with the
manufactures specifications.




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