Fremantle Port Inner Harbour and Channel ... - Fremantle Ports

• If water quality does not improve and is deemed to be an ongoing environmental risk,
the following hierarchy of management measures shall be implemented as soon as is
practicable:
o Where relevant to each particular analyte for which an exceedance has
occurred, further testing of water samples may be conducted to ascertain the
‘bioavailable’ fraction or potential ecotoxicity of the analyte, for comparison
with relevant guidelines as per ANZECC/ARMCANZ (2000a), EPA (2005a)
and/or appropriate alternate guidance.
o The cause of any exceedance shall be investigated, potentially including water
quality monitoring for toxicants at additional sites and/or at an increased
frequency.
o Any exceedance of high protection triggers shall also initiate water quality
sampling for toxicants at public beach sites for assessment against triggers for
primary contact recreation as described in Section 5.1.2 - Water Clarity and
Aesthetics of Primary Contact Areas (Beaches and Lower Swan).
o Additional protection barriers shall be implemented, e.g. additional silt curtains,
raising of weir box to reduce flow volume of return water.
o Return water discharge shall cease until it can be demonstrated that no risk to
the environment is posed by toxicants.
Water pH within Return Water Plume
Frequency
• Baseline prior to discharge of reclamation water, then weekly until the completion of
reclamation and conclusion of return water discharge, and one week thereafter or until
water quality meets HEPA criteria.
Location
• Six sites including one site within the reclamation pond, one site within the weir box,
three ‘dynamic transect’ sites within the return water plume (at distances 10 m,
200 m and 500 m from silt curtain) and two ‘static reference’ sites within the
Cottesloe Reef Fish Habitat Protection Area, as shown in Figure 3.1 (N.B. ‘mock’ sites
at the same distances of separation along a transect offshore of the return water
discharge outlet / weir box, shall be used for (i) baseline sampling and (ii) water
quality sampling in the week subsequent to conclusion of return water discharge).
Method
• Measure pH of surface water (50 cm below water surface, at least 5 water samples)
and bottom water (50 cm above sediment surface, at least 5 water samples) at each
site every week in accordance with EPA (2005a,b).
• Compare median pH of surface and bottom waters at potential impact sites against
‘reference’ sites for moderate and high protection triggers as listed in Table 4.4 (i.e.
potential impact sites to exhibit no greater deviation than ±0.2 pH units from
reference sites), to determine the appropriate management response as listed below.
Contingency Management Measures
• Where pH is determined to exceed the trigger level, then:
o the CEO of the Office of the EPA will be informed of the exceedance and
proposed management strategies (see below) as soon as practicable and no
later than within 72 hours of detection of the exceedance (i.e. subsequent to
processing of pH data);
o if applicable, any management actions already implemented within 72 hours
shall also be reported; and
o all management strategies will be implemented as soon as practicable.
• The exceedance will also be noted in fortnightly reporting (by the Environmental
Monitoring Contractor) to Fremantle Ports and the Office of the EPA;
• If water pH does not improve and is deemed to be an ongoing environmental risk, the
following hierarchy of management measures shall be implemented as soon as is
practicable:
o The cause of exceedance shall be investigated.
o Additional protection measures shall be implemented, e.g. raising of weir box
to reduce flow volume of return water.
Oceanica: Fremantle Ports: Inner Harbour and Channel Deepening - Water Quality Monitoring Program 23