Appendix B- SWMP

                                                                                        23098 - SBSMP/2
                                                                                                 Page 15




6.3.2 Proposed Treatment Train
The proposed treatment train has been modelled using the following methodology:

Proposed Development Catchment

    1. Roofwater from the proposed roof catchments will flow via downpipes to above ground
       rainwater tanks for treatment with overflow to an internal drainage network.

    2. Surface runoff from the proposed ground catchment will be directed to an end of line
       bioretention basin for treatment, which is located in the north eastern corner of the site.

All runoff described above will then discharge to the legal point of discharge. The Concept Site
Levels and Drainage Plans of the proposed internal drainage network detailing the treatment train
assets are included in Appendix F. Refer to Table 6-5 for details of the proposed treatment train
assets.

                                Table 6-5 - Proposed Treatment Assets

          Treatment          Treatment
                                                                    Description
            Level              Asset

                           Rainwater Reuse
                                                Total of 12.5kL located adjacent to each proposed
           Primary/       Tanks (Landscape
                                                building, irrigating an area of 627m2 and servicing
          Secondary       Irrigation, Toilets
                                                toilets and laundry for all units.
                             and Laundry)

          Primary/                                   9m2 Total Filter Area
         Secondary/      Bioretention Basin          0.4m Filter Media Depth
          Tertiary                                   0.1m Extended Detention Depth


Refer to Appendix K for the Stormwater Quality Operational Management and Maintenance
Guidelines.

6.3.3 Pollutant Export Modelling
Following the definition of water quality objectives for the site and an assessment of the treatment
options suitable for the development, the most appropriate treatment scheme for the site was
identified. The impact of the stormwater management strategy on the quality of stormwater runoff
discharged from the site has been assessed using the pollutant export model, Model for Urban
Stormwater Improvement Conceptualisation (MUSIC).

6.3.4 MUSIC Modelling Parameters
The MUSIC model was set up in accordance with the Water-By-Design MUSIC Modelling Guidelines
for South East Queensland to the parameters listed in Table 6-6. Refer to Figure 6.1 for source
node areas in the proposed development area.




Site Based Stormwater Management Plan
Proposed Townhouse Development at 5 Pearl Street, Cooroy