Negotiated Decision Notice - MCU24 0125, OPW24 158 & RAL24 0021 (As Published) · MCU24/0125

               43.    Prescribed Water Contaminants (as defined in the Environmental Protection Act 1994) must
                      not be released from the site or to waters within the site, or be likely to be released should
                      rainfall occur, unless all reasonable and practicable measures are taken to prevent or
                      minimise the release and concentration of contamination. These measures must be
                      designed, implemented and maintained in accordance with “Best Practice Erosion and
                      Sediment Control” published by the International Erosion Control Association (Australasian
                      Chapter) (IECA, 2008), to the extent that such measures and practices are also consistent
                      with the following:
                      a.      Minimise erosion:
                              i.        Restrict the extent of clearing to that necessary for access to and safe
                                        construction of the approved works;
                              ii.       Protect vegetation in all other areas of the site;
                             iii.       Minimise the duration of soil exposure by undertaking land clearing and
                                        stabilisation according to the rainfall erosion hazard as specified in IECA (2008)
                                        Tables 4.4.2 and 4.4.7
                             iv.        Prior to either the approval of the plan of survey for the development or
                                        commencement of use, all site surfaces are to be effectively stabilised using
                                        methods that 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:
                              i.        Implement drainage and erosion control measures (including contingency
                                        measures), prior to rainfall, which prevent or minimise rill erosion and gully
                                        erosion.
                              ii.       Ensure clean stormwater is diverted/managed around or through the site
                                        without increasing the concentration of total suspended solids or other
                                        contaminants in the flow and without causing erosion (on-site or off-site). If it is
                                        not feasible to divert all areas discharging clean stormwater around or through
                                        the site, the clean stormwater runoff is managed in the same manner as
                                        contaminated stormwater runoff and ensures that sediment basins are sized to
                                        accommodate the additional volume of runoff.
                             iii.       Prior to each rainfall event ensure concentrated stormwater flow paths are
                                        provided with capacity in accordance with IECA (2008) Table 4.3.1 and do not
                                        cause water contamination, rill or gully erosion, sedimentation or damage to
                                        structures or property.
                      c.      Minimise sediment released from the site:
                              i.        All site sub-catchments greater than 2,500m2 in area, are to be provided with
                                        sediment controls which are designed, implemented and maintained to a
                                        standard which would achieve at least 80% of the average annual runoff volume
                                        of the contributing catchment treated (i.e. 80% hydrological effectiveness) to
                                        50mg/L Total Suspended Solids (TSS) or less, and pH in the range 6.5–8.5.
                                        Where this is proposed to be achieved through the use of sediment basins, the
                                        following applies:
                                        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) unless otherwise justified, based on the contributing catchment area
                                           including undisturbed catchments which cannot be diverted;




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Document Set ID: 24095782
Version: 12, Version Date: 05/09/2025