Reference Document - Dewatering Management Plan (For Stamping) MCU25/0053 & OPW25/0074

                                                                                                                                           ADG Consulting Pty Ltd

                              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)                                                                              ≤141

                               Turbidity (NTU)                                                                                      ≤61

                               Dissolved metals (µg/L)

                               Aluminium                                                                           No relevant ANZG criterion available

                               Arsenic                                                                            No relevant ANZG criterion available*

                               Cadmium                                                                                              5.52

                               Chromium                                                                                             4.42

                               Copper                                                                                               1.32

                               Iron                                                                                No relevant ANZG criterion available

                               Lead                                                                                                 4.42

                               Nickel                                                                                               702

                               Zinc                                                                                                  82

                               Mercury                                                                                              0.42

                               Total 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 (moderately disturbed – Noosa River – canals and marinas).
                              2. ANZG (2018) – Marine water trigger values for 95% species protection (Supersedes ANZECC/ARMCANZ (2000)).
                              3. Criteria subject to expected condition in Development Application (DA) notice by Noosa Shire Council.

                              Although ADG has not been provided a copy of any DA notice or conditions for the proposed development
                              (not yet available at the time of writing), based on previous dewatering projects in the Noosa Coast
                              Region it is expected that total iron and aluminium concentrations as listed in Error! Reference source
                              not found. (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 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

                        ADG1777.25 Dewatering Management Plan_Rev0_01.05.25                                                                                    Page 8




Document Set ID: 23735664
Version: 1, Version Date: 12/05/2025