Minor Change Existing Approval OPW19 0266 03 · OPW19/0266.03

                      Bioretention Basins – Construction
               38.    The 150mm diameter collector pipe and riser sections of the sub-soil drains of the
                      bioretention device are to be provided as solid-walled pipes and not slotted. The Sub-soil
                      pipes may be laid on zero grade for a saturated zone system. The drainage layer is to be
                      increased to a minimum depth of 350mm.
               39.    During construction and establishment of the bioretention devices, the supervising RPEQ
                      must ensure that the device was 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 commencement of use.
               40.    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).
                      The drainage layer, transition layer, and filtration media materials shall not be installed until
                      the catchment draining to the bioretention device has 70% groundcover as determined by
                      Council’s delegate.
                      Bioretention Basins – Maintenance
               41.    The bioretention device must be maintained in accordance with the document titled ‘Bio-
                      Retention Operational Management and Maintenance Guideline’ provided as Appendix E of
                      the ‘Site Based Stormwater Management Plan’ prepared by Morgan Consulting Engineers
                      dated 12th March 2020. The approved Operational Works drawings for the stormwater quality
                      treatment system and detailed life cycle costing of the system must be attached as an
                      addendum to this document. Records of all maintenance activities undertaken must be kept
                      and made available to Council upon request.
               42.    Any proposed Community Management Statement required for the development must
                      include the document titled ‘Bio-Retention Operational Management and Maintenance
                      Guideline’ provided as Appendix E of the ‘Site Based Stormwater Management Plan’
                      prepared by Morgan Consulting Engineers dated 12th March 2020 and must include the full
                      cost of maintaining the system in accordance with this document. The cost of maintaining
                      the system must be included in the proposed levies for each unit owner.
                      Environment
               43.    Prescribed Water Contaminants (as defined in Schedule 9 of Environmental Protection
                      Regulation 2008) 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:



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Document Set ID: 22642068
Version: 2, Version Date: 31/10/2023