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

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o o Management measures shall be implemented to neutralise return water to within acceptable pH range. Return water discharge shall cease until it can be demonstrated that no risk to the environment is posed from unacceptably low (or high) water pH. Dissolved Oxygen within proximity of Inner Harbour Dredge, Return Water, Offshore Dredge and Disposal Plumes Frequency • Baseline prior to dredging or discharge of reclamation water, then weekly (or fortnightly at Inner Harbour sites monitored by DoW) until the completion of dredging or reclamation and conclusion of return water discharge, and one week thereafter or until water quality meets relevant criteria. • Monitoring will be targeted and focussed on data collection at those sites within proximity of the visible plume/s (as based on field observation and aerial imagery), which technically defines the potential zone of influence, plus associated reference sites. That is, not all sites may be sampled, and to reiterate for emphasis, when dredging only those sites within proximity of the visible dredge, disposal and/or return water plumes will be sampled, plus associated reference sites. Location Total of twenty-one sites including: • Four ‘dynamic transect’ sites within the Inner Harbour dredge plume (at distances 10 m, 50m, 100 m and 500 m from dredge head) as detailed in Section 3.3, Figure 3.1 and Figure 3.2 (N.B. ‘mock’ sites at the same distances of separation along a transect within the Inner Harbour, at a random location overlying the footprint of potentially contaminated sediment, shall be used for (i) baseline sampling and (ii) water quality sampling in the week subsequent to dredging of that sediment, if the dredge has moved out of the Inner Harbour). • 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). • Three water quality sites surrounding the Inner Harbour, monitored by the DoW, as detailed in Section 3.6 and Figure 3.1 (N.B. salinity and total nutrients will also be monitored by the DoW at these sites for contextual purposes). • Eight ‘dynamic transect’ sites within the offshore dredge plume (4 sites) and disposal plume (4 sites) (at distances 10 m, 50m, 100 m and 500 m from dredge head or location of spoil disposal) as detailed in Section 3.4 and Figure 3.1 (N.B. ‘mock’ sites at the same distances of separation along a transect within the offshore deep water channel and disposal area, at a random location overlying the footprint of sediment to be dredged and disposed shall be used for (i) baseline sampling and (ii) water quality sampling in the week subsequent to dredging and disposal of that sediment). Method • Measure daytime DO saturation within bottom waters (0-50 cm from sediment surface) at each site every week (or fortnight at DoW sites) in accordance with EPA (2005a,b). • For contextual purposes TSS concentration will also be determined at each location by collection of a single integrated-depth water sample, sent to a NATA-accredited laboratory for analysis of the concentration and determination of the organic component via loss on ignition (LOI). • For contextual purposes the water turbidity (NTU) and temperature profile will also be measured at each location. • For contextual purposes, Secchi depth will also be measured at each site in accordance with EPA (2005a,b). • Compare rolling 2-week median DO saturation of bottom waters at each potential impact site against EQG triggers for moderate and high protection as listed in Table 4.4. 24 Oceanica: Fremantle Ports: Inner Harbour and Channel Deepening - Water Quality Monitoring Program
• If EQG triggers are exceeded, determine whether environmental quality standards (EQS) for high or moderate protection areas as defined by EPA (2005a) have been exceeded (i.e. rolling 2-week median DO shall not be below 60% saturation), to determine the appropriate management response as listed below. Contingency Management Measures • Where DO saturation is determined to breach the EQS 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 DO 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 bottom water DO saturation 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 Daily monitoring shall be implemented. o Additional protection barriers and measures 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. o Further management measures shall be implemented to ensure that bottom water DO saturation meets the applicable standard, e.g. single-shift dredging. o Dredging shall be relocated from the area subject to DO exceedance until the Office of the EPA is satisfied that the risk to the environment is acceptable. 5.1.2. Recreational and Aesthetic Values Water Clarity and Aesthetics of Primary Contact Areas (Beaches and Lower Swan) Frequency • Weekly for the first 6 weeks of the dredging program, and thereafter only if prompted by visual analysis of weekly aerial imagery and/or a significant number of public complaints. • Aerial imagery to be collected every second day for the duration of dredging of the 300,000 m 3 potentially contaminated sediment within the Inner Harbour. Location • Six contingency ‘recreation/aesthetic’ beach sites as detailed in Section 3.5 and Figure 3.1. Method • Measure Secchi depth at each site every week in accordance with EPA (2005a,b). • For contextual purposes TSS concentration will also be determined at each location by collection of a single integrated-depth water sample, sent to a NATA-accredited laboratory for analysis of the concentration and determination of the organic component via loss on ignition (LOI). • Compare Secchi depth at each site against triggers for primary contact recreation as listed in Table 4.4 (i.e. Secchi depth should be no less than 1.6 m), to determine the appropriate management response as listed below. Oceanica: Fremantle Ports: Inner Harbour and Channel Deepening - Water Quality Monitoring Program 25
Page 1: Fremantle Port Inner Harbour and Ch
Page 5: Client: Fremantle Ports Revisions h
Page 8 and 9: 7. Quality Assurance / Quality Cont
Page 11 and 12: 1. Introduction 1.1. Scope of this
Page 13 and 14: 2. Environmental Values and Objecti
Page 15 and 16: 3. Monitoring Sites 3.1. Water Qual
Page 17 and 18: 3.7. Provision of monitoring site c
Page 19 and 20: Figure 3.2 Inner Harbour and Rous H
Page 21 and 22: Table 4.2 Depth-specific Light Atte
Page 23: 4.2. Sentinel Mussel Quality 4.2.1.
Page 26 and 27: Table 4.5 Toxicants in water - indi
Page 28 and 29: Table 4.7 Toxicants in sediment - i
Page 30 and 31: o The extent and position of the vi
Page 32 and 33: • If water quality does not impro
Page 36 and 37: Contingency Management Measures •
Page 38 and 39: at the same distances of separation
Page 40 and 41: this Project (SKM 2008) and Fremant
Page 42 and 43: 7. Quality Assurance / Quality Cont
Page 44 and 45: • Date of analysis and name of te
Page 46 and 47: 8. References ANZECC / ARMCANZ 2000

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

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