Swmp

5.3.3   Pollutant Modelling
The impact of the stormwater quality management strategy of runoff discharged from the site has been
assessed using the Pollutant Export Model, Model for Urban Stormwater Improvement
Conceptualisation (MUSIC).
For our model the proposed treatment train has been modelled: -
        1.    Roof water from all units will be collected by a rainwater re-use tank. Water tanks will
              be fitted with an overflow to an onsite Bio retention basin. The rainwater tank will be re-
              used for area landscaping irrigation & Commercial Grey water only, to all common areas.

        2.    Surface runoff from ground hardstand and landscaping areas will be collected by
              numerous catch pits and pipes. The internal drainage network will then be discharged
              into the onsite bio retention basin for treatment.


The Music Model was set up in accordance with the Water by Design Music Modelling Guidelines for
Southeast Queensland. Design parameters are listed below:


Bioretention Bed A
        •
              Surface Area                                 =        20m2
        •
              Filter Media Area                            =        20m2
        •
              Filter Depth                                 =        0.4m
        •
              Extended Detention                           =        0.20m
        •
              Hydraulic Conductivity                       =        180mm/ Hr
        •
              TN content of Filter Media                   =        500mg/ kg
        •
              Orthophosphate content of Filter Media       =        5mg/ kg


Bioretention Bed B
        •
              Surface Area                                 =        5m2
        •
              Filter Media Area                            =        5m2
        •
              Filter Depth                                 =        0.4m
        •
              Extended Detention                           =        0.20m
        •
              Hydraulic Conductivity                       =        180mm/ Hr
        •
              TN content of Filter Media                   =        500mg/ kg
        •
              Orthophosphate content of Filter Media       =        5mg/ kg


Water Tank
        •
              Volume                                       =        25kL

        •
              Re-use for Commercial Grey Water & Landscaping



5.3.4   Proposed Treatment Train
The Music Model was set up in accordance with the Water by Design Music Modelling Guidelines for
Southeast Queensland.


Figure 5.1 displays a print screen of the MUSIC Model Schematic for the proposed development and

Figure 5.2 displays the annual pollutant loads that will be discharged from the proposed development.

 SCG Consulting engineers                           9                       SCG Ref: 33094(SWM).Rev A