Negotiated Decision Notice OPW26 0033 (As Published)

                      Stormwater Drainage
               53.    Appropriate scour protection must be provided at the outlet of all stormwater pipes including
                      temporary outlets.
               54.    Works associated with this permit must not adversely impact on the existing drainage
                      conditions on other properties (e.g., by blocking or interfering with natural overland flows).
               55.    Construction of all internal stormwater drainage works must comply with the relevant
                      section/s of Australian Standard AS/NZS 3500.3.
                      Bioretention Basins – Construction
               56.    The bioretention devices must be constructed in accordance with the document Construction
                      and Establishment Guidelines: Swales, Bioretention Systems and Wetlands (Water by
                      Design, 2009). Option 1 of the staged construction and establishment methods is to be
                      followed as documented in the guidelines.
               57.    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.
               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.




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Document Set ID: 25209919
Version: 4, Version Date: 02/10/2026