Amended Stormwater Managment Plan

SC5594 – Walter Hay Dr, Noosaville                                                                8


3.3.2    Catchment Areas
Table 3.3 illustrates the proposed roof, carpark/hardstand, and landscape areas to be treated as part of the
development site. A large existing landscape area as part of the overall stormwater catchment (Refer
Section 4.0) will remain mostly undisturbed post-development. Therefore, as no increase in impervious
areas or significant change in topography is proposed over this area this has been excluded from MUSIC
modelling.



                                                                     % Impervious
                                                                       (Per MUSIC
                   Node                     Description                                Area (Ha)
                                                                        Modelling
                                                                       Guidelines)
                 Combined                       Roof                       100            0.355
             Post-development          Carpark/hardstand areas             100            0.197
                Catchments           Development Landscape Only             25            0.100
                               Total MUSIC Model Catchment (Ha)                           0.652
                            Table 3.3 - Post Development Sub–Catchment Areas



3.3.3    Pollutant Export Modelling
The Model for Urban Stormwater Improvement Conceptualisation (MUSIC) has been utilised to calculate
pollutant loads from the proposed development and to predict performance characteristics of the proposed
treatment train. Modelling parameters used were adopted from the Water by Design “Music Modelling
Guidelines for South-East Queensland”, and the updated MUSIC Version 5 recommended parameters for
Bio-retention basin nodes. MUSIC modelling setup and results are attached within Appendix B.


Under the proposed conditions, the site was ‘split’ into three land use catchment nodes; the roofed area,
driveways and ground level uses. The pollutant export parameters utilised were based on the Urban
Residential pollutant loads, refer Tables 3.4 & 3.5. The pollutants have been generated stochastically in the
modelling scenario.