MCU25 0079 - Negotiated Reference Documents (As Published)

                 Table 3 - Existing vs developed peak flow rates

                     AEP Storm Event         Existing peak flow rate   Developed peak flow        Change in peak flow
                                                     (L/sec)               rate (L/sec)                  rate
                                                                                                       (L/Sec)

                              1EY                       20                      21                          1

                             0.5EY                      26                      27                          1

                             0.2EY                      36                      38                          2

                              10%                       40                      42                          2

                              5%                        47                      50                          3

                              2%                        59                      60                          1

                              1%                        66                      66                          0

                 As shown in Table 3, the peak flow rate of stormwater runoff has marginally increased for the developed
                 case from that of the existing case as a result of the increase in impervious area. Due to the marginal
                 increase in flow, and that the proposed kerb outlets will also not exceed a flow of greater than 25L/s for
                 the design event (10%), stormwater detention is not considered to be required.

                 4      W AT ER Q U AL IT Y M A NAG E M EN T


                 4. 1       O pe r at io na l Ph a se

                 The proposed development is not required to meet the Queensland Governments State Planning Policy
                 (July 2017) as the development site area does not exceed the 2,500m2 minimum. Table SC6.14.3G of
                 the SCRC Planning Scheme Policy for Development Works (PSPDW) states that stormwater quality
                 management must still be undertaken by the harvesting and reuse of roof water runoff and runoff from
                 impervious area is to be directed to landscaped areas where possible.

                 Pollutants typically generated during the operational phase of the development include:

                        •    Litter/gross pollutants;
                        •    Sediment;

                        •    Nutrients (N & P);

                        •    Hydrocarbons (oils and grease); and

                        •    Heavy metals.

                 4. 2       Con st ruc t io n Ph a se

                 Management of stormwater runoff during construction and the implementation of an erosion & sediment
                 control program is necessary to avoid impacts to receiving waters from pollutants typically generated
                 during the construction phase. Typical pollutants are described in Table 4 below:

                 Table 4 – Pollutants Typically Generated During the Construction Phase




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Document Set ID: 23959990
Version: 1, Version Date: 23/07/2025