Attachment C - Stormwater report

4.4.3.3.     Infiltration System
A stormwater infiltration system holds runoff and allows it soak into the ground. The ponds are open
facilities with grass or sand bases. They can either drain rapidly or act as permanent ponds where water
levels rise and fall with stormwater flows. Generally, infiltration basins are managed like detention ponds
but with greater emphasis on maintaining the ability to infiltrate stormwater. The parameters utilised to
analyse the infiltration system are presented in Table 11.
Table 11 – Infiltration System Input Parameters.

Catchment ID                                                               Infiltration System Parameters
                        2
Pond Surface Area (m )                                                                  450

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

Saturated Hydraulic Conductivity (mm/hr)                                                200

Filter Depth (m)                                                                        0.5


4.4.4.       MUSIC Results
The results of the MUSIC modelling are presented in Table 12. The bioretention system was sized to
achieve the Best Practice water quality objectives for urban developments. The media filtration system and
infiltration system have been modelled as the same size.




Stormwater Management Plan – Lot 1 on SP108094, 305 Lake Macdonald Drive                                    Page 19

D’VINERIPE
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