Decision Notice OPW25 0057 · OPW25/0057

                              iii.     Prior to the sealing of the plan of survey for the development, all site surfaces
                                       must be effectively stabilised using methods which have achieved effective short-
                                       term stabilisation and which will continue to achieve effective stabilisation in the
                                       medium to long-term. For the purpose of this condition, an effectively stabilised
                                       surface is defined as one that does not, or is not likely to result in visible evidence
                                       of soil loss caused by sheet, rill or gully erosion or lead to sedimentation, or lead
                                       to water contamination.
                      b.      Manage concentrated stormwater flows
                              iv.      Prior to each rainfall event ensure concentrated stormwater flow paths are
                                       provided with capacity in accordance with IECA (2008) Table 4.3.1 and are
                                       structurally stable in all rainfall events for the following sources:
                                       a)    From stormwater catchments upslope of the area of disturbance which are
                                             either stable or external to the site, ensure stormwater is diverted or
                                             managed either:
                                             i.    around the site or through the site without causing erosion and
                                                   without contaminating the flow; or
                                             ii    if it is impractical to convey the flows around or through the site,
                                                   convey the flows into appropriately sized sediment basins without
                                                   causing erosion.
                                       b)    From all disturbed areas of the site to sediment basin(s) without causing
                                             erosion
                      c.      Minimise sediment released from the site
                              i.       Prior to each rainfall event ensure concentrated stormwater flow paths are
                                       provided with capacity in accordance with IECA (2008) Table 4.3.1 and are
                                       structurally stable in all rainfall events for the following sources:
                                       a)    Each basin is sized and operated in accordance with either a Type-A or
                                             Type-B sediment basin as documented in IECA (2008) Appendix B (June
                                             2018).
                                       b)    Each basin is to be provided with an automated system of flocculent dosing
                                             and a suitable supply of flocculent/coagulant, with the type of
                                             flocculent/coagulant determined based on Chemical Coagulants and
                                             Flocculants Fact Sheet (IECA, 2018).
                                       c)    Markers are provided within each basin indicating the maximum sediment
                                             storage level and any additional water storage capacity for water reuse.
                                       d)    During discharge from the primary outlet system, the concentration of total
                                             suspended solids (“TSS”) discharged does not exceed 50mg/L and that pH
                                             is within the range of 6.5-8.5 unless entering a naturally acidic environment.
                              ii.      Install and maintain additional sediment control measures within the site, as
                                       necessary to maximise sediment capture.
                              iii.     Minimise the tracking of dirt from the site onto roadways. Ensure that all dirt on
                                       roadways caused by vehicles leaving the site is removed without causing water
                                       contamination, prior to rainfall and at least at the end of each work day.
               52.    Sediment and erosion control measures must be in place prior to works commencing. If such
                      measures are not in place or are not satisfactory, “on the spot” fines may be issued. Such
                      fines can be issued if sediments from the site are found to enter or have the potential to enter
                      Council’s stormwater system, natural waterways, any downstream stormwater filtration
                      system or adversely impacting on other properties. The sediment and erosion control design
                      and measures have NOT been approved, it is the site's Supervising Engineer who is
                      responsible for ensuring that the sediment and erosion control measures have:




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Document Set ID: 24052669
Version: 2, Version Date: 22/08/2025