Attachment C - Stormwater report

6.3.         Drainage Control
6.3.1.       Design Standard
Based on the calculated soil loss, the following design standards apply to construction phase drainage and
erosion and sediment control:
         Temporary drainage structures                    39% AEP event (assuming design life < 12 months)

Roof runoff from the greenhouse is currently conveyed to a sediment basin via open drains. The operators
are in the process of installing a pipe drainage system to convey runoff to this location. However, no details
have been provided in relation to the design of these drains or the pipe drainage system.

6.4.         Sediment Control
6.4.1.       Design Standard
For any future construction activities, the following standards summarised in Table 18 apply to sediment
control.
Table 18 - Sediment Control Standard based on Soil Loss Rate

         Area Limit                                            Sediment Loss Rate Limit (t/ha/.yr)
            (m²)                             Type 1                         Type 2                    Type 3
            250                               n/a                             n/a                       n/a
           1,000                              n/a                             n/a                    All cases
           2,500                              n/a                            > 75                        75
          > 2,500                            > 150                            150                        75

Therefore, Type 2 and Type 3 controls are applicable for sediment control on the site. Examples of Type 2
and Type 3 controls that could be employed on site include:

         Type 3:
             o Sediment Fence,
         Type 2:
             o Filter Bag or Filter Tube,
             o Filter Pond, and
             o Filter Tube Dam.




Stormwater Management Plan – Lot 1 on SP108094, 305 Lake Macdonald Drive                                         Page 28

D’VINERIPE
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