Noosa Springs SMP_Rev 4 · OPW17/0612

ALTUM CONSTRUCTIONS
PRECINCT F & E2 NOOSA SPRINGS DEVELOPMENT



          5.   Maintenance and monitoring criteria for necessary water quality improvement
               devices.

4.1.1     Proposed Treatment Train

          The proposed treatment train utilises a series of Bioretention Basins and Infiltration
          Swales to treat stormwater runoff as it flows within the proposed developments. All water
          to flow into the bioretention basins will be captured via the under drainage and overflow
          riser pit, this water will be directed into the below ground stormwater network which will
          discharge into the existing Noosa Springs lake system.

          There will be three (3) Infiltration Swales located around the facilities area central to
          Precinct F, these swales will also act as conveyance systems for flows exceeding the
          infiltration rate of the filter media discharged into the piped stormwater drainage network.

          Based on the operation of the proposed arrangement all water entering the piped
          drainage network will trigger the requirements of Part 1a of Condition 49. However all
          runoff lost from the system via infiltration will enter the groundwater table and eventually
          discharge to Lake Weyba in the south. This proportion of stormwater runoff from the
          development technically bypasses the Noosa Springs Lake System and therefore triggers
          the requirements of Part 2b of Condition 49.

          The stormwater quality management approach has ensured the concentration of
          pollutants in runoff discharged from the two sites combined (Precinct F and Precinct E2)
          are lower than the existing concentrations at the discharge location.

          Additionally the Noosa Springs Lake System was originally designed to provide water
          quality treatment for the Precinct F and Precinct E2 developments and therefore the runoff
          discharged to the lake system will undergo further treatment prior to entering the natural
          environment (Lake Weyba).

4.1.2     Climate Data

          Climate data for the catchment was sourced from the Bureau of Meteorology (BOM).
          Rainfall data was obtained from Cooroy Composite (40059) for the 10 years between
          1973 and 1983 at six (6) minute intervals as specified by MUSIC Modelling Guidelines for
          South East Queensland (Water by Design, 2010).

4.1.3     Catchment Properti es

          The catchment area for water quality is based on the proposed development layout. A
          lumped catchment approach was considered appropriate and adopted for the
          assessment. Rainfall-runoff and pollutant export parameters were adopted from the
          recommended values identified in Tables 3.7 and 3.8 of MUSIC Modelling Guidelines for
          Southeast Queensland (Water by Design, 2010). Table 4.1 provides a summary of the
          MUSIC Model parameters adopted with the various land uses throughout the study area.
          Fraction impervious is sourced from the recommended values provided by MUSIC
          Modelling Guidelines for Southeast Queensland (Water by Design, 2010).

Job No. M7130_001                                                                              Page 6
                                                                               Rev 4 : 7 December 2017