ADG1673.24 Dewatering Management Plan_Rev0_12.07.24

                                                                                                             ADG Consulting Pty Ltd


     Table 3 Receiving waters criteria

                               Parameter                                                           Criteria

       Physico‐chemical
       pH (pH units)                                                                              7.5 – 8.11
       Dissolved oxygen (% saturation)                                                            85 – 1051
       Suspended solids (mg/L)                                                                       ≤161
       Turbidity (NTU)                                                                               ≤131
       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                                                                                            82
       Mercury                                                                                       0.42
       Totals metals (µg/L)
       Aluminium                                                                            No ANZG criteria / 2003

       Iron                                                                                 No ANZG criteria / 3003

     Table notes:
     1. DES (2022). Noosa River environmental values and water quality objectives (middle estuary waters) – Weyba Creek.
     2. ANZG (2018). Supersedes ANZECC/ARMCANZ (2000) ‐ Marine water trigger values for 95% species protection.
     3. Criteria subject to expected condition in Development Application (DA) notice by Noosa Shire Council.
     * = Insufficient data to derive a reliable trigger value. Low reliability value adopted (refer ANZECC/ARMCANZ (2000) Section
     8.3.7.

     Although ADG has not been provided a copy of the DA notice and conditions for the proposed
     development, based on previous dewatering projects in the Sunshine/Noosa Coast Region it is expected
     that total iron and aluminium concentrations as listed in Table 3 (above) are likely to be conditioned by
     Noosa Shire Council for compliance. It should be noted that these concentrations are considered to be
     onerous with respect to the risk‐based (worst‐case) bioavailable trigger value criteria contained in ANZG
     2018 & ANZECC/ARMCANZ (2000) for marine water (moderately disturbed) 95% species protection, and
     are likely to be difficult to achieve given the groundwater conditions encountered in the locality on
     previous dewatering projects on the Sunshine/Noosa Coast.

     Prior to discharge to the stormwater system or any waterway, discharges are to be tested to meet the
     requirements of the ANZG 2018 & ANZECC/ARMCANZ (2000) Guidelines for Fresh and Marine Water
     Quality. There is currently no chemical toxicant trigger value criteria available for total or dissolved (i.e.
     bioavailable) concentrations of aluminium or iron for marine or estuarine waters under the Australian
     and New Zealand Guidelines for Fresh and Marine Water Quality Guidelines (ANZG 2018 &
     ANZECC/ARMCANZ 2000 – i.e. ANZECC Guidelines) or the Guidelines for Managing Risks in Recreational
     Waters (NHMRC 2008), with regards to managing environmental impacts to the waterway.

     In addition, Section 5 (Guidelines for recreational water quality and aesthetics) of the ANZECC/ARMCANZ
     (2000) Guidelines (per section 5.2 thereof) was superseded by the Guidelines for Managing Risks in
     Recreational Water in 2008 (NHMRC, 2008). Therefore, a reference to the ANZECC/ARMCANZ (2000)
     Guidelines is by association and extension a reference to the current 2008 NHMRC Guidelines. The 2008
     NHMRC Guidelines contain no criteria for aluminium, and only includes an aesthetic criterion for iron –
     noting this is an aesthetic criterion derived from the Australian Drinking Water Guidelines on the basis of


ADG1673.24 Dewatering Management Plan_Rev0_12.07.24                                                                                 Page 8