Decision Notice OPW25 0057 · OPW25/0057

                      Bioretention Basins – Maintenance & handover
               44.    Following installation of the filter media for the bioretention devices, a temporary cover
                      consisting of a suitable geotextile covered with soil and turfed is to be immediately installed.
                      This temporary cover is to be maintained in place for a minimum period of 24 months
                      following acceptance of the bioretention devices On Maintenance or until 80% of building
                      works has been completed (whichever occurs first). Following this period the temporary
                      cover is to be removed, and the approved plantings installed. The bioretention devices are
                      then to be appropriately maintained for a minimum period of 12 months prior to being
                      accepted as Off Maintenance by Council’s delegate.
               45.    A construction hold point with a council delegate must be established when the temporary
                      cover is to be removed from the bioretention device an inspection must be arranged with
                      Council’s delegate
               46.    Prior to acceptance of the basin either on or off maintenance, council must receive evidence
                      that the results for the in-situ hydraulic conductivity testing conducted in accordance with
                      FAWB PRACTICE NOTE 1: In Situ Measurement of Hydraulic Conductivity Belinda Hatt,
                      Sebastien Le Coustumer April 2008 for the bioretention filter media achieve the design
                      criteria.
               47.    Subsoil drains are to be cleaned out and accumulated sediment manually removed from the
                      surface of basin and coarse sediment forebays at Off Maintenance and as required during
                      the maintenance period.
               48.    All stormwater quality treatment devices must be maintained by the development in
                      accordance with Water by Design (2009) Maintaining Vegetated Stormwater Assets (Version
                      1) until they are accepted as Off Maintenance by Council.
               49.    Any defects in WSUD devices identified during the maintenance period must be reviewed
                      and a report recommending required rectification works submitted to Council and endorsed
                      by Council’s delegate. Works to repair the device and prevent the problem occurring in the
                      future must be completed and the device maintained for a minimum period of 12 months prior
                      to the WSUD device being accepted as Off Maintenance.
               50.    Prior to council accepting the bioretention devices Off Maintenance, maintenance checklists
                      including the full cost of maintaining the devices in accordance with Water by Design (2009)
                      Maintaining Vegetated Stormwater Assets (Version 1) must be submitted to Council.
                      Erosion and Sediment Control
               51.    Prescribed Water Contaminants (as defined in Schedule 10 of Environmental Protection
                      Regulation 2019) 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.       For areas of the site which drain to a sediment basin, implement drainage and
                                       erosion control measures prior to rainfall which prevent or minimise rill erosion
                                       and gully erosion
                              ii.      For areas of the site which do not drain to a sediment basin, implement drainage
                                       and erosion control measures prior to rainfall (including contingency measures)
                                       which prevent or minimise erosion, including rain drop erosion, chemical erosion,
                                       rill erosion and gully erosion




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