Noosa Springs SMP_Rev 4 · OPW17/0612

ALTUM CONSTRUCTIONS
PRECINCT F & E2 NOOSA SPRINGS DEVELOPMENT



          Table 4.1 MUSIC Model Parameters

                    Catchments            MUSIC Land Use       Roof Area (ha)   Road Area (ha)      Ground Area (ha)

                                                              100% Impervious   60% Impervious       20% Impervious

             To Swale 1 (North East)      Urban Residential        0.227              -                      -

                    To Basin 1            Urban Residential        0.021            0.359                 0.391

                    To Swale 2            Urban Residential        0.093            0.129                 0.816

                    To Swale 3            Urban Residential          -              0.054                 0.199

           To Basin 2 (Local Catchment)   Urban Residential        0.061            0.121                 0.128

                    To Basin 3            Urban Residential        0.180            0.248                 0.408

                     Untreated            Urban Residential        0.262            0.554                 1.851


4.1.4     Exfiltration Rat e

          Soil permeability at this site has been assessed using empirical relationships with
          laboratory PSD results. The results of the PSD testing for all three samples from site were
          similar, resulting in a calculated hydraulic conductivity of 2.56 x 10-4 m/s (920 mm/hr). In
          order to account for reductions in hydraulic conductivity associated with sediment and
          organic matter an exfiltration rate of 500 mm/hr has been adopted within the MUSIC
          model.

4.2       Treatment Sizing and Location

          The proposed treatment system consists of three (3) bioretention basins and seven (7)
          infiltration swales.

4.2.1     Bioretenti on Basins

          Three month ARI flows will enter the bioretention systems from either the underground
          drainage network and via overland flow. Once the extended detention depth is exceeded
          in the basins, stormwater will overtop the overflow riser pit and be discharged to the piped
          drainage network.

          Scour protection and coarse sediment forebay calculations will be undertaken as part of
          the detailed design stage of the application in accordance with the WSUD Technical
          Design Guidelines for South East Queensland.

          Bioretention basin parameters have been adopted using the WSUD Technical Design
          Guidelines for South East Queensland and the Water by Design MUSIC Modelling
          Guidelines for Southeast Queensland, with the exception of the exfiltration rate applied to


Job No. M7130_001                                                                                           Page 7
                                                                                            Rev 4 : 7 December 2017