Approved Plans - MCU18-0097 · MCU18/0097

                 GOOD SHEPHERD LUTHERAN COLLEGE                                                              ODYSSEY CONSULTING GROUP
                 Lot 30 on SP170751                                                               Conceptual Stormwater Management Plan
                 115 Eumundi Noosa Road, Noosaville                                                                     Project No: K4277

                          Post Development Modelling Results - Mitigated
                          The stormwater quality improvement device (SQID) will reduce the amount of sediments and
                          nutrients discharging from the proposed residential development. Table 18 illustrates the treatment
                          train effectiveness of the proposed SQID’s.

                          Table 18:        Treatment Train Effectiveness of Proposed SQID
                                       Parameter                Post         Post Mitigated   Reduction (%)     Water Quality Objectives
                                       Flow (ML/yr)             6.66              6.57             1.5                       -
                                        TSS (kg/yr)             2590              461             82.2                     80%
                                        TP (kg/yr)              4.56              1.15            74.8                     60%
                                        TN (kg/yr)               21               10.5            49.9                     45%
                                Gross Pollutants (kg/yr)         125               0              100                      90%

                          The results demonstrate that the proposed SQID meet the intended water quality objectives for flow,
                          suspended solids, phosphorous and nitrogen levels.



                 6.0 OPERATIONAL PHASE MAINTENANCE REQUIREMENTS
                          The proposed stormwater management devices will require maintenance and monitoring to ensure
                          that they function as designed. The following section provides an outline of the necessary
                          maintenance tasks for the proposed devices.

                 6.1      Bio-retention Basin Maintenance
                          The most intensive period of maintenance is during the plant establishment period (first two years)
                          when weed removal and replanting may be required. It is also the time when large loads of
                          sediments could impact on plant growth particularly in developing catchments with poor building
                          controls.

                          Maintenance is primarily concerned with:
                                Maintenance of flow to and through the bio-retention basin;
                                Maintaining vegetation;
                                Preventing undesired overgrowth vegetation from taking over the bio-retention basin;
                                Removal of accumulated sediments; and
                                Litter and debris removal.

                          Vegetation maintenance will include:
                                Fertilising plants;
                                Removal of noxious plants or weeds; and
                                Re-establishment of plants that die.

                          Sediments accumulated at the inlets need to be monitored. Depending on the catchment activities
                          the deposition of sediment can tend to smother plants and reduce the ponding volume available.
                          Should excessive sediment build-up it will impact on the plant health and require removal before it
                          reduces the infiltration rate of the filter media. The proposed SQIDs will require regular maintenance
                          and monitoring to ensure that they function as designed.




                 K4277-0002-E                                            18 June 2019                                       Page 13 of 14
Document Set ID: 20894174
Version: 1, Version Date: 03/07/2019