Decision Notice OPW20 145 06 (As Published) · OPW20/0145.06

               46.    During construction and establishment of the bioretention devices, the supervising RPEQ
                      must ensure that the device is constructed in accordance with the document Construction
                      and Establishment Guidelines: Swales, Bioretention Systems and Wetlands (Water by
                      Design, 2009) and that the forms contained in section 3.15 including the associated
                      supporting information and data are completed. These forms and certification from the RPEQ
                      that the device has been constructed in accordance with the Construction and Establishment
                      Guidelines: Swales, Bioretention Systems and Wetlands (Water by Design, 2009), all
                      conditions of approval, and the approved engineering drawings must be submitted to Council
                      prior to plan sealing
               47.    A construction hold point with a council delegate shall 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
               48.    A construction hold point with a council delegate shall be established when the temporary
                      cover is to be removed from the bioretention device an inspection shall be arranged with
                      Council’s delegate
               49.    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.
                      Bioretention Basins – Maintenance & handover
               50.    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.
               51.    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.
               52.    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.
               53.    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.
                      Bioretention Basins - Education
               54.    The development shall be provided with approved Permanent signage to educate the public
                      on the function of the bioretention basin. The wording for the signage for each bioretention
                      basin is to include: “BIORETENTION BASIN - This bioretention basin reduces the pollution
                      of our waterways by reducing the amount of heavy metals, litter, suspended solids, and
                      nutrients discharged to Lake Weyba”.




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Document Set ID: 24395463
Version: 4, Version Date: 03/02/2026