O2 stormwater Report Rev Oct 2015

Table 8 - Water Quality Objectives.

                         Minimum reductions in Mean Annual Loads from unmitigated catchment

   Total Suspended Solids                Total Phosphorus                  Total Nitrogen           Gross Pollutants
             (TSS)                              (TP)                           (TN)                      > 5mm

              80%                               60%                            45%                          90%



4.4.3.       Treatment Options
MUSIC modelling has been undertaken to assess the treatment system requirements to achieve the above
water quality objectives.
4.4.3.1.     Media Filtration System
An alternative to a bioretention system is the media filtration system. Runoff is directed to a pit containing
filtration media which removes suspended solids and nutrients from the water before dispersing it into the
soil. It has been determined a media filtration system will be capable of achieving the load based reduction
targets for the site. The parameters utilised to analyse the media filtration system are presented in Table
9. A concept plan for the media filtration system, showing a typical cross section and footprint of the
system is included within Appendix C.
Table 9 – Media Filtration System Input Parameters

                                                                             Media Filtration System Parameters

Extended Detention Depth (m)                                                                0.3
                2
Filter Area (m )                                                                            400

Saturated Hydraulic Conductivity (mm/hr)                                                    100

Filter Depth (m)                                                                            0.5

NOTE: The results of the effluent disposal assessment have been utilised and an infiltration rate of
10mm/hr assumed for the modelling associated with the media filtration system.
4.4.3.2.     Swale
Runoff will be conveyed from the greenhouse roof to the media filtration system by a swale. The length of
swale varies, subject to the location of the downpipes from the roof area. As a conservative approach, a
flow length of 100mm has been assumed for runoff within the swale.
Table 10 - Swale Node Reporting Table

                                                                                   Swale Input Parameters

Length (m)                                                                                  100

Bed slope (%)                                                                               0.5


Stormwater Management Plan – Lot 1 on SP108094, 305 Lake Macdonald Drive                                          Page 12

D’VINERIPE
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