Appendix 3 - Stormwater quality management plan

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



To target these potential pollutants, stormwater quality improvement devices (SQIDs) will be
incorporated within the development in order to reduce pollutants and to meet the desired water
quality objectives.

2.3.1.   Water Quality Objectives (WQOs)
The proposed development falls within the “South East Queensland” region of the State Planning
Policy July 2017 (Queensland Government, 2017). Table 2.2 indicates the minimum load reduction
targets required to be met under this policy.

                           Table 2.2 - Water Quality Objectives (WQOs)

                            Pollutant                        % Load Reduction

               Total Suspended Solids (TSS)                         80%

               Total Phosphorus (TP)                                60%

               Total Nitrogen (TN)                                  45%

               Gross Pollutants >5mm (GP)                           90%



2.3.2.   Pollutant Export Modelling
The Model for Urban Stormwater Improvement Conceptualisation (MUSIC) has been utilised to predict
performance characteristics of the proposed treatment train. Modelling parameters were obtained
from the recommendations specified in MUSIC Modelling Guidelines: Version 1.0 – 2010 (Water By
Design, 2010), (the Music Guidelines).

A ‘’Split Catchment” MUSIC model was generated, whereby the model contained 3 sub-catchments
representing the ground areas (driveways and car park) and roof areas connected to the reuse tanks
and the roof areas connected directly to the drainage system.        For the purposes of modelling
simplicity, other ground level uses such as landscaping and footpaths etc were conservatively
absorbed into the road areas. Table 2.3 indicates the contributing areas of each sub-catchment
modelled and the spatial extents of these sub-catchments are shown on the concept drainage plans
attached as Appendix B.      The pollutant export parameters utilised were based on commercial
pollutant loads, as recommended by the Music Guidelines. Table 2.4 gives an overview of the
catchment areas and parameters used within the MUSIC model. The node layout for the MUSIC
model is displayed as Figure 2.1.

                        Table 2.3 - Summary of Site Sub-Catchment Areas
                                                          Area
                                         Catchment
                                                          (Ha)
                                     Ground / Road       0.106
                                     Roof to Tank        0.0250
                                     Roof to Drain       0.0556
                                     Total (Ha)          0.186



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