Amended Site-Based Stormwate Management Plan · RAL18/0023

4.3 MUSIC Modelling

MUSIC (Version 6.2, eWater), a pollutant export modelling program has been used to model
both the expected pollutant loads generated by the development and the effectiveness of
WSUD treatment options selected.

4.3.1 Split Catchment Approach

The MUSIC model is based on a split catchment approach, modeled as various catchments
representing the different surface types in accordance with the guidelines and available site
information. Split catchment surface information can be found in Table 4.2 below. The
fraction impervious was calculated from proposed sealed pavement areas, and rounded up
to the nearest 5% to account for minor adjustments in detailed design.

                            Surface Type                       % Imperviousness
                            Road Reserve                   Varies (75% / 70% / 60%)
                                        Table 4.2 Adopted % Imperviousness


Table 4.3 lists the total areas for the surface type in the catchment that was used in the
model. The total area is the proposed total extent of the road reserve area. Refer to the
Catchment Plan in Appendix A demonstrating these areas within the proposed development.


                          Node                                               Area (ha)
               West Hofmann Drive C1                                         0.1150

               West Hofmann Drive C2                                         0.2545

               West Hofmann Drive C3                                         0.1250

                         Road A                                              0.2265

                    Road A Bypass                                            0.0270

                         Road B                                              0.4070

                Driveway and Reserve                                         0.2270

                          Total                                              1.3820
                                          Table 4.3 Surface Area of Nodes




4.3.2 MUSIC Meteorological Data

Cooroy DPI (Station 40059) meteorological data was selected for the MUSIC analysis. The
10-year climate period was selected in accordance with Table 3.1 of the guidelines. The
rainfall and evapo-transpiration data for the period of 01/01/1973 to 31/12/1983, with a 6-
minute time step was used in the model.


Site Based Stormwater Management Plan                                                    Page 10 of 20
1856-SBSMP-01_Version 3.0 (May 2019)