RECOR Preliminary Stormwater Management Report - 20220130

                                           Figure 3.2 – DRAINS Post-development catchments


The results of the modelling against the range of design storms for the development under the existing and
proposed development conditions are shown in Table 3.1 Existing and proposed unmitigated site peak discharge
rates.
                              Table 3.1 Existing and proposed unmitigated site peak discharge rates

                                                                       Delorme Street
                                                                                                       Qchange
                                           A.E.P               Qexisting     Qproposed    Qchange       (%)
                                                               (m³/s)        (m³/s)       (m³/s)
                                            1EY                0.014          0.016       0.002         14%
                                            50%                 0.016         0.018       0.002         13%
                                           0.2 EY               0.025         0.027       0.002          8%
                                            10%                 0.032         0.032          0           0%
                                             5%                 0.036         0.036          0           0%
                                             2%                 0.041         0.042       0.001          2%
                                             1%                 0.045         0.046       0.001          2%




The proposed development will result in a maximum of 2L/s increase across all storm events under the increased
2100 climate rainfall conditions, which is considered an insignificant increase beyond the present levels. As the
locality is not prone to flooding and no drainage issues have been identified, this small increase is not expected to
result in any significant impacts or risks to downstream infrastructure, therefore no attenuation is proposed for the
development.

In accordance with the Sustainable Building Design code, a 3,000L rainwater tank per dwelling is to be provided. A
low flow outlet consisting of a 43mm orifice plate in each tank is to be provided at the base of each tank, and a
100mm high flow outlet at the head of the tank will provide discharge for larger storm events. The high flow outlet
will be plumbed into the site’s internal drainage network.




Project number 20220130
File RECOR Preliminary Stormwater Management Report - 20220130, 2022-11-08                                         Page 9 of 15
Revision 3


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