Sealed Judgement

Figure 3-3 Post-Development Split Catchment Plan


3.4.2         Characteristics of Detention System

Table 3-6 contains the dimensions and outlet configurations of the modelled detention system.
Table 3-6    Modelled Detention System

 Detention               Dimensions        Outlet Configuration

 A1_Rainwater tank     - 2 x 3 kL = 6 kL   - 80 mm diameter orifice at tank invert
                        - 0.98 m height    - 4x300mm diameter pipes at 0.9m above the tank
                                           invert to cater for surcharging from the tank when
                                           full.

 A_Rainwater tank       - 5 x 3 kL = 15    - 100 mm diameter orifice at tank invert.
                               kL          - 10x300mm diameter pipes at 0.89m above the
                        - 0.98 m height    tank invert to cater for surcharging from the tank
                                           when full.

 Underground               - 120 m2        - 50mm diameter orifice at tank invert.
 detention tank         - 0.5 m height     - 4.0 m weir at 0.46m above the tank invert.
                            - 60 m   3
                                           (a grate would also be provided in the car park to
                                           allow for surcharging in extreme events).


With reference to the above table, it is noted that although Catchment A drains to the bioretention
basin, no detention is considered to occur within the basin.




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