Swmp

      3.3.2. Sediment Forebays

      To ensure that the deposition of coarse sediment on the filter media surface does not affect
      its function, bioretention systems should be designed with pre-treatment to limit the amount
      of coarse sediment reaching the filter media. The sediment forebay has been sized in
      accordance with the WaterByDesign’s Bioretention Technical Design Guideline. Table 3-6
      summarises the proposed design parameters for the proposed sediment forebay.
      Table 3-6: Sediment Forebay Design Parameters

                                          Parameter                          Bioretention Basin
                                                                                     A

                                     Site Catchment (ha)                           1.384
                                 Min Area of Forebay (m2)                           15
                                    Removal Efficiency (%)                          80



             Results
      MUSIC modelling of the proposed treatment train for the developable area of the
      development at 25 Pavilion Street, Pomona was performed to ensure the WQO’s were
      achieved. Table 3-7 presents the load-based outputs that are represented by this
      application. The results show the mitigated scenario, which achieves compliant load
      reductions set out within the NSC Planning Scheme.
      Table 3-7: MUSIC Results – Load Based Pollutant Outputs

        Pollutant       Unmitigated          Mitigated         Reduction         Target           Compliance
                          (kg/yr)             (kg/yr)         Achieved (%)     Reduction
            TSS              13.5               13.2                2.6           80%                 ✓
            TP              2740                 526                80.8          60%                 ✓

            TN               5.33               1.39                 74           45%                 ✓
            GP               27.9               13.7                 51           90%                 ✓




21-0166SMP01-V1 | Stormwater Management Plan | 25 Pavilion Street, Pomona                                      | 14