Compiled Reference Document - MCU25/0020 (As Published)

ADG Consulting Pty Ltd

 

Parameter Criteria
Aluminium No ANZG criteria / 200?
Iron No ANZG criteria / 3002

Table notes:

1. DES (2022). Noosa River environmental values and water quality objectives (tidal canals, constructed estuaries, marinas and
boat harbours).

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.

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 iron or total concentrations of aluminium 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(2000) Guidelines (per section 5.2 thereof) was superseded by the Guidelines for Managing Risks in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
ingesting 2L of the recreational water solution per day. ANZECC/ARMCANZ (2000) Section 5.2.3.3, notes
that as a general guideline, under Toxic Chemicals, ‘Higher concentrations of toxicants may be tolerated
occasionally if it assumed that no person will ingest more than a maximum of 100 mL water during a
normal swimming session (NHMRC 1990) compared with 2L/d for potable water’, and Section 3.1.1.3,
under Risk based approach of the guidelines, ‘The guideline trigger values are based on bioavailable
concentrations, and hence are relatively conservative when compared with total concentrations in the
field, so the use of the decision frameworks will increase guideline concentrations in most cases’.
Therefore, any chemical toxicant trigger values would require reassessment and likely increase upwards
of any ANZG 2018 &/or ANZECC/ARMCANZ (2000) Guideline trigger values due to the slightly to
moderately disturbed nature (and thereby reduced sensitivity) of the receiving waters.

In conditioning more onerous criteria, rather than the available marine chemical toxicant trigger value
criteria contained within the ANZG/ANZECC Guidelines, an unachievable constraint may be placed on the
development. This DMP has allowed for contingency measures to be incorporated into the treatment
and discharge system if required, including silt curtains to be installed within the receiving waterway
surrounding the discharge location, or further onsite treatment measures such as filtration, to prevent
and/or minimise as far as reasonably practicable the potential for release of suspended solid loads into
the broader receiving waterway.

 

ADG1786.25 Dewatering Management Plan_Rev1_07.10.25 Page 9