SUPERSEDED - Decision Notice OPW26 0033 (As Published)

               58.    A construction hold point with a Council delegate must be established once the bioretention
                      device underdrainage pipe work is installed.
                      At the time of inspection, a sample of the drainage layer, transition layer, and filtration media
                      materials must be stockpiled on-site. Laboratory results must be provided for the filter media
                      which demonstrate that the media complies with the specifications contained in the latest
                      version of the “Guidelines for Soil Filter Media in Bioretention Systems” (produced by the
                      Facility for Advancing Water Biofiltration) and that the minimum hydraulic conductivity
                      specified on the approved engineering plans will be achieved. In addition, laboratory results
                      must be provided demonstrating that the transition layer and drainage layer meet the
                      following bridging criteria:
                      a.      D15 (drainage layer) ≤ 5 × D85 (transition layer)
                      b.      D15 (transition layer) ≤ 5 × D85 (filter media)
                      Bioretention Basins – Maintenance & handover
               59.    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.
               60.    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.
               61.    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.
               62.    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.
               63.    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.
               64.    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
               65.    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.
               66.    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.


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Document Set ID: 25057225
Version: 2, Version Date: 14/08/2026