Noosa Springs SMP_Rev 4 · OPW17/0612

ALTUM CONSTRUCTIONS
PRECINCT F & E2 NOOSA SPRINGS DEVELOPMENT



4.4       Water Quality Model Results

4.4.1     Flow s Entering the Noosa Spri ngs Lake System

          The water quality modelling results for water entering the Noosa Springs Lake System
          from the Noosa Springs development are summarised in Table 4.4. These results are
          presented as the average concentration of pollutants in outflows from the system and
          have been compared to the water quality in the existing Noosa Springs Lake system at
          the discharge point (W5). For the purposes of comparison the proposed discharge levels
          have been compared to average results for all documented records between December
          2008 and March 2016, as well as the latest recorded results from March 2016.

          Table 4.4 Water Quality Assessment

                 Location           TSS Concentration            TN Concentration             TP Concentration

              Noosa Springs         Average: 15.4 mg/L          Average: 0.781 mg/L           Average: 0.07 mg/L
               development
                                     Median: 0.00 mg/L           Median: 0.00 mg/L            Median: 0.00 mg/L
             (Precinct F & E2)
                                 90th Percentile: 30.5 mg/L   90th Percentile: 2.26 mg/L   90th Percentile: 0.23 mg/L

              Noosa Springs         Average: 0.41 mg/L           Average: 0.01 mg/L           Average: 0.00 mg/L
               development
                                     Median: 0.00 mg/L           Median: 0.00 mg/L            Median: 0.00 mg/L
            (Precinct E2 ONLY)
                                 90th Percentile: 0.00 mg/L   90th Percentile: 0.00 mg/L   90th Percentile: 0.00 mg/L

              Existing Noosa         Average: 149 mg/L             Average: 4 mg/L            Average: 0.23 mg/L
              Springs Lakes
              (Location W5)           Median: 11 mg/L             Median: 1.5 mg/L             Median: 0.11 mg/L

              (2008 – 2016)       90th Percentile: 491 mg/L    90th Percentile: 3.0 mg/L   90th Percentile: 0.24 mg/L


             Water Quality at
             existing Noosa
             Springs Lakes               1320 mg/L                    30.5 mg/L                    2.16 mg/L
             (Location W5)

               (March 2016)


          The information presented in this table proves the water quality of runoff from the
          proposed Noosa Springs development (Precinct F and E2) will be compatible with the
          existing water quality in the Noosa Springs Lake System at the discharge point (W5). In
          fact, the water quality is significantly better than the existing conditions in the lake.

          It is noted that the median concentrations TSS, TN and TP are below two significant
          figures. This is because pollutant loads are dominated by high pollutant concentration
          events which are unaccounted for by the median values.




Job No. M7130_001                                                                                          Page 9
                                                                                           Rev 4 : 7 December 2017