H - Revised Integrated Water Management Plan by Cardno (inc MUSIC file) (13.09.19)

          Saturated Zone required
              for plant health                                                                             YES
                                                                                                                  Submerged Zone
        and/or stormwater treatment                                                                                drainage profile
                           NO



      Treated Water will be harvested                                          YES


                           NO


            Dispersive, sodic, or                                              YES
         acid sulphate soils present

                           NO

                                                                                                                  Fully lined system
    Elevated groundwater table present                                         YES                                with slotted pipe
                                                                                                                   underdrainage
                           NO

 Restrictions to infiltration of flow present
        (i.e. infrastructure damage)                                           YES
   and building foudations within 3m
                           NO


             Surrounding soil                                                  YES
    hydraulic conductivity <0.25mm/hr

                           NO

              Surrounding soil
           hydraulic conductivity                                                                          YES
                                                                                                                 Unlined system with
       < twice that of the filter media                                                                              sloteed pipe
                           NO


                                                                                                                   Unlined system
                                                                                                                 without slotted pipe
                                                                                                                    underdrainage
Figure 5 – Drainage Profile Decision Tree for WSUD Tree Pit




    3.3.9 Liners and Geotextiles
    Impermeable and permeable liners are often required in WSUD tree pit systems. Impermeable liners may be required
    to partially or fully line the base and sides of WSUD tree pit system if water cannot be exchanged between the tree pit
    and the surrounding soil profile.
    Non-woven geotextile liners should be applied to the sides of a WSUD tree pit system where the surrounding soils can
    migrate into more porous fill layers like the filter, transition, or drainage layers.
    Reinforced filter fabrics are heavy grade non-woven geotextile liners which incorporate a reinforced mesh. The liners
    are applied to the top and sides of a tree pit system to spread vertical and lateral loads as well as prevent the migration
    of fines into the tree pit soil fill profile.
    A detailed discussion regarding the application of liners in WSUD systems is provided in Section 3.2.4 of Bioretention
    Technical Design Guidelines6


    6. Water by Design, 2012. Bioretention Technical Design Guidelines. Healthy Waterways Brisbane, QLD.




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