Stormwater Treatment & Water Quality Management Plan_April2014

                                                                              Callaghan & Toth


6.       CONCLUSIONS & RECOMMENDATIONS
An integrated water management approach has been used to assess the site’s stormwater
requirements and water management needs. In summary:

        The proposed reconfiguration at 55 Lake MacDonald Drive and Pearsons Road from
         four (4) lots into Fifty-seven (57) lots can be treated by a stormwater treatment train
         consisting of:
         o One medium Bioretention Basin (BioBasin 1)(already completed for Stage 1 i.e. Lots
             1 to 4),
         o Two large Bioretention Basins located in park treating runoff from Lots 5 to 16 and
             associated road reserve for BioBasin 3 and treating runoff from Lot 33 to 57 for
             BioBasin 2.
         o Three small Roadside Bio Basins treating runoff from Lots 20 to 25 and associated
             road reserve,
         o Two Bioretention swales treating runoff from Lots 17,19, 29 to 32 and associated
             road reserve,
         o Three Raingardens for Lots 26, 27 & 28, and
         o A grassed buffer for the road joining the new development to Blue Wren Place.

        This proposed stormwater treatment train achieves the current best practice load based
         reduction targets as prescribed in the Water by Design Deemed to Comply Solutions –
         Stormwater Quality Management (South East Queensland) version 1.0 – Table A-2
        The new lots have sufficient flood free areas to build residential infrastructure in
         accordance with Council’s requirements.
        The increased flood storage achieved with the measures:
                    o Detention volume in Bio Basins 2 and 3,
                    o Watercourse reshaping for the Western tributary,
                    o Revegetation of riparian areas to “roughen” the catchment, and
                    o Constructing a restrictive footbridge across the eastern tributary;
         Allows attenuation of the runoff concentrations back to Pre Development levels and so
         the development will not have an impact on the hydrology of the downstream receiving
         waters.




55 Lake MacDonald Drive – Stage 1 to 5                                                   pg. 24