OPW20.0191 NC IR response

Engineering Response to Item 4
PO10 of the Water Quality and Drainage Code and demonstration how the proposed
works are compliant with this portion of the code is shown in Table 2 below is listed
below.


Performance                Acceptable Outcomes                          Demonstrated Compliance
Outcomes                                                                with PO10
Hydrology                                                              AO10.1 – There is no change to the
and waterway stability      AO10                                       pre and post stormwater discharge
PO10                        The development is designed to:            rates.
Development prevents                  1. limit the peak 1
increased bed and bank                    year ARI event discharge     AO10.2 – There is no increase to
erosion and sedimentation                 within the                   impervious area
in receiving waterways by                 receiving waterway to the
avoiding changes in low                   pre-development peak 1       AO10.3 – The proposed development
rate, peak flow run-off and               year discharge;              will include some capture and re-use of
flow duration.                        2. maximise pervious areas by stormwater via the proposed dams.
                                          using pervious alternatives These dams will be used to assist in
                                          for otherwise impervious     providing water for livestock and
                                          areas wherever possible;     irrigation if required.
                                      3. provide for capture and
                                          reuse of stormwater for non- A010.4 – No detention features are
                                          potable purposes for         required as the proposed development
                                          gardening, toilet flushing,  will not result in an increase in
                                          laundry and hot water supply stormwater discharge.
                                          uses;
                                      4. incorporate appropriate       AO10.5 – The proposed outlets to the
                                          detention features; and      streams have incorporated natural
                                      5. incorporate natural channel channel design principles. These
                                          design principles            principles ensure that the discharge of
                                                                       stormwater into Kinmond Creek occurs
                            Editor’s note: The Sustainable Building    at the invert of the creek to ensure that
                            Design Code includes requirements for      bank erosion does not occur.
                            stormwater capture and reuse.              Furthermore, measures such as a
                                                                       plunge pool and large stone pitching
                                                                       has been used near the entry to the
                                                                       creek to ensure stormwater velocities
                                                                       of water entering the creek are
                                                                       minimised. The reduced stormwater
                                                                       velocities will ensure that the
                                                                       development does not increase creek
                                                                       bed and bank erosion.



Table 2 – PO10 of the Water Quality and Drainage Code and how the proposed
development complies with this portion of the code.

NC Information Required for Item 5

Provide detailed drawings including information on, but not limited to:
        5.1. cross-sections and dimensions of the proposed swale drains;
        5.2. stormwater discharge outlets;
        5.3. how the proposed swales and stormwater outlets will be stabilised.




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