ADG Dewatering Management Plan · OPW21/0315

                                                                                                         ADG Consulting Pty Ltd


     guideline values are triggers to further action, are inherently conservative, and that the response to non-
     compliance should match the magnitude and impacts (if any) of the exceedance.

     Regardless of the WQOs adopted in this DMP, the General Environmental Duty set out in the EP Act is
     paramount, which requires that “a person must not carry out an activity that causes or is likely to cause
     environmental harm unless the person takes all reasonable and practicable measures to prevent or
     minimise the harm”.
4.3 Proposed water quality objectives
     The proposed water quality objectives that have been developed for the discharge of extracted
     groundwater from the site are provided in the Tables below. All water discharged from the site must
     comply with the discharge criteria provided in Table 2. In addition, the receiving water quality within a
     20 m radius of the discharge point entry to the receiving water shall comply with the receiving water
     criteria provided in Table 3. Receiving waters data will be assessed against background monitoring data
     if non-compliant results are obtained at the receiving waters monitoring location.

     Table 2 Discharge criteria

                              Parameter                                                        Criteria

       Physico-chemical
       pH (pH units)                                                                          6.5 – 8.51
       Dissolved oxygen (% saturation)                                                           >802
       Suspended solids (mg/L)                                                                  <501,2
       Turbidity (NTU)                                                                           <502
       Litter                                                                               None visible
     Table notes:
     1. QWQG 2009 (2013) Refer to Table 8.2.1. Summary of design objectives for management of stormwater quality and flow –
        construction phase of development in Queensland.
     2. Typical discharge criteria recognised throughout Queensland & NSW.

     Table 3 Receiving waters criteria

                              Parameter                                                        Criteria

       Physico-chemical
       pH (pH units)                                                                          7.8 – 8.31
       Dissolved oxygen (% saturation)                                                        85 – 1051
       Suspended solids (mg/L)                                                                   <201
       Turbidity (NTU)                                                                            <81
       Dissolved metals (µg/L)
       Aluminium                                                                   No relevant ANZG criteria available

       Arsenic                                                                                   2.32*
       Cadmium                                                                                   5.52
       Chromium                                                                                  4.42
       Copper                                                                                    1.32
       Iron                                                                        No relevant ANZG criteria available

       Lead                                                                                      4.42
       Nickel                                                                                     702
       Zinc                                                                                       152
       Mercury                                                                                   0.42
       Totals metals (µg/L)



ADG1290.21 Dewatering Management Plan_Rev0_12.10.21                                                                       Page 7