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Port Hedland Port Authority South West Creek Dredging and Reclamation Project - Dredging Management Plan
South West Creek Dredging Approvals
Dredging Management Plan
301012-01318-EN-REP-0005
22 December 2010
PROJECT 301012-01318 - SOUTH WEST CREEK DREDGING APPROVALS
REV DESCRIPTION ORIG REVIEW WORLEY-
PARSONS
APPROVAL
DATE CLIENT
APPROVAL
DATE
0 Issued for Use
T Al-Hashimi
D Collins
T Al-Hashimi
4-Nov-10
1 Final for Issue to
Government
T Al-Hashimi
G Connell
T Al-Hashimi
22-Dec-10
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Port Hedland Port Authority South West Creek Dredging and Reclamation Project - Dredging Management Plan
Disclaimer
This report has been prepared on behalf of and for the exclusive use of Port Hedland Port
Authority, and is subject to and issued in accordance with the agreement between Port Hedland
Port Authority and WorleyParsons Services Pty Ltd. WorleyParsons Services Pty Ltd accepts no
liability or responsibility whatsoever for it in respect of any use of or reliance upon this report by
any third party.
Copying this report without the permission of Port Hedland Port Authority and WorleyParsons
Services Pty Ltd is not permitted.
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CONTENTS
1. Introduction ............................................................................................................................................ 1
1.1 Project Overview.....................................................................................................................................1
1.2 Project Location ......................................................................................................................................1
1.3 Aim of the Plan........................................................................................................................................2
1.4 Key Environmental Legislation/Standards/Guidelines............................................................................2 1.4.1 Commonwealth Legislation ............................................................................................................2 1.4.2 State Legislation..............................................................................................................................3 1.4.3 Relevant Standards and Guidelines ................................................................................................4
1.5 PHPA Environmental Policy.....................................................................................................................7
1.6 Stakeholder Consultation........................................................................................................................7
2. Roles and Responsibilities ....................................................................................................................... 9
3. Project description .................................................................................................................................10
3.1 Proposed Dredge Footprint...................................................................................................................11
3.2 Offshore Disposal..................................................................................................................................11
3.3 Dredge Material Management Areas...................................................................................................12
4. Studies and Predicted Impacts ...............................................................................................................15
4.1 Water Quality .......................................................................................................................................16 4.1.1 Sediment Plume Modelling...........................................................................................................17 4.1.2 Mobilisation of Contaminants ......................................................................................................25
4.2 Mangroves ............................................................................................................................................26 4.2.1 Direct Impacts...............................................................................................................................26 4.2.2 Indirect Impacts ............................................................................................................................26
4.3 Other BPPH ...........................................................................................................................................27 4.3.1 Dredge Footprint and Onshore Disposal Areas ............................................................................27 4.3.2 Spoil Ground I ...............................................................................................................................29
4.4 Marine Fauna........................................................................................................................................29
4.5 Introduction of marine pests.................................................................................................................30
4.6 Potential Acid Sulphate Soils.................................................................................................................30
4.7 Terrestrial Flora and Fauna...................................................................................................................30
4.8 Dust Management ................................................................................................................................31
4.9 Hydrocarbon and Chemicals .................................................................................................................31
4.10 Waste Management .............................................................................................................................31
5. Management Implementation ...............................................................................................................33
5.1 Water Quality .......................................................................................................................................33 5.1.1 Overview.......................................................................................................................................33 5.1.2 Management Actions....................................................................................................................34
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5.2 Mangroves Habitats .............................................................................................................................35 5.2.1 Overview.......................................................................................................................................35 5.2.2 Management of Mangrove Habitats.............................................................................................36
5.3 Other Marine Habitats (non-mangroves) .............................................................................................37 5.3.1 Overview.......................................................................................................................................37 5.3.2 Management of Marine Habitats (non-mangroves).....................................................................37
5.4 Marine Fauna........................................................................................................................................38 5.4.1 Overview.......................................................................................................................................38 5.4.2 Management of Marine Fauna .....................................................................................................39
5.5 Introduced Marine Species ...................................................................................................................41 5.5.1 Overview.......................................................................................................................................41 5.5.2 Management of Introduced Marine Species ................................................................................42
5.6 Hydrocarbon Management ..................................................................................................................43 5.6.1 Overview.......................................................................................................................................43 5.6.2 Management of Hydrocarbon Spills .............................................................................................43
5.7 Waste Management .............................................................................................................................45 5.7.1 Overview.......................................................................................................................................45 5.7.2 Management of Wastes................................................................................................................46
5.8 Offshore Spoil Ground Management....................................................................................................47 5.8.1 Overview.......................................................................................................................................47 5.8.2 Management of Spoil Ground ......................................................................................................47
5.9 Onshore Dredge Material Management ..............................................................................................49 5.9.1 Overview.......................................................................................................................................49 5.9.2 Management of the DMMAs ........................................................................................................50
6. Monitoring Programs and Inspections ...................................................................................................52
6.1 Tiered Monitoring Framework..............................................................................................................52
6.2 Routine Marine Water Quality Monitoring Program............................................................................56 6.2.1 Development of Trigger levels......................................................................................................56 6.2.2 Monitoring Sites............................................................................................................................56 6.2.3 Methodology ................................................................................................................................60 6.2.4 Frequency .....................................................................................................................................62 6.2.5 Data Analysis and Reporting .........................................................................................................62
6.3 Coral Health Monitoring Program ........................................................................................................63 6.3.1 Monitoring Sites............................................................................................................................63 6.3.2 Method .........................................................................................................................................64 6.3.3 Frequency .....................................................................................................................................64 6.3.4 Data Analysis and Reporting .........................................................................................................65
6.4 Routine Surface Sediment Profiling Monitoring Program.....................................................................65 6.4.1 Trigger Levels ................................................................................... Error! Bookmark not defined. 6.4.2 Frequency ........................................................................................ Error! Bookmark not defined. 6.4.3 Location ........................................................................................... Error! Bookmark not defined. 6.4.4 Method ............................................................................................ Error! Bookmark not defined. 6.4.5 Parameters and procedures ............................................................ Error! Bookmark not defined. 6.4.6 Data analysis and reporting ............................................................. Error! Bookmark not defined.
6.5 Mangrove Health Monitoring Program ................................................................................................66
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6.5.1 Frequency .....................................................................................................................................66 6.5.2 Location ........................................................................................... Error! Bookmark not defined. Method .........................................................................................................................................................67 6.5.3 Data Analysis and Reporting .........................................................................................................68
6.6 Onshore Dredge Material Management Area Monitoring ...................................................................69 6.6.1 Methodology ................................................................................................................................69 6.6.2 Data analysis and reporting ..........................................................................................................70
7. Reporting ...............................................................................................................................................71
8. Auditing ....................................................................................................... Error! Bookmark not defined.
9. References .............................................................................................................................................75
Appendices
Appendix 1 – PHPA’s Environmental Policy
Appendix 2 – PHPA’s Marine Oil Pollution Management Plan
Tables
� Table 1-1: Pilbara coastal waters environmental values and environmental quality objectives....................6 � Table 1-2: Pilbara coastal waters levels of ecological protection linked to the maintenance of ecosystem
integrity ..................................................................................................................................................................7 � Table 2-1 Positions and responsibilities of key personnel associated with the Project...................................9 � Table 3-1: Key parameters of the Project .....................................................................................................10 Table 3-2 Coordinates of relevant project infrastructure (GDA94 Z50) ............................................................14 � Table 4-1 Summary of identified impacts, management and risk associated with the Project....................15 � Table 4-2 Summary of water quality recorded in South West Creek between December 2009 and May 2010
(WorleyParsons 2010) –Bolded values represent exceedance of adopted AZNZECC ARMCANZ guidelines.........16 � Table 6-1: Proposed Water Quality Monitoring Sites for Offshore Disposal ................................................57 � Table 6-2: Proposed Water Quality Monitoring Sites for Dredging and at the DMMAs...............................57 � Table 6-3: Proposed Coral Monitoring Sites for Offshore Disposal...............................................................63 � Table 6-4: Proposed Coral Monitoring Sites for Dredging ............................................................................63 � Table 7-1 Reporting requirement to be undertaken during dredging and disposal activitiesError! Bookmark
not defined.
Figures
� Figure 1-1: Dredge footprint including intertidal disturbance corridor, layout of berths and turning circle ..1 � Figure 1-2: Location of Spoil Ground I.............................................................................................................1 � Figure 1-3: Location of Dredge Material Management Areas (DMMAs) .......................................................1 � Figure 3-1: Cutter Suction Pipelines at DMMA H as part of BHPBIO RGP6 Expansion (BHPBIO 2009)........13 � Figure 4-1: TSS (mg/L) Predicted for Energetic Conditions (95
th percentile) at Spoil Ground I .....................19
� Figure 4-2: TSS (mg/L) predicted for ambient conditions (50th
percentile) at Spoil Ground I .......................20 � Figure 4-3 TSS (mg/L) predicted for 5% of the time in surface waters (A) bottom waters (B) (mg/L) during
phase B to G (note phase A is not shown due to low and uniform TSS concentration across the creek system of
les than 5 mg/L)....................................................................................................................................................21
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� Figure 4-4: Average TSS concentration (mg/L) in surface (A) and bottom (B) waters during phase B to G
(note phase A is not shown due to low and uniform TSS concentration across the creek system of les than 5
mg/L) ....................................................................................................................................................................22 � Figure 4-5: Sedimentation (g/m
2) deposited within and adjacent to the Spoil Ground I over the dredge
program ...............................................................................................................................................................23 � Figure 4-6: Predicted cumulative sediment deposition in mass (g/m
2) (A) and thickness (mm) (B) at the end
of each phase B to G simulations (note: Phase A is not shown due to low predicted sedimentation) .................24 � Figure 6-1: Routine Water Quality and Reactive Coral Monitoring Tiered Management Framework .........54 � Figure 6-2: Routine Surface Sedimentation Profiling and Reactive Mangrove Health Tiered Management
Framework............................................................................................................................................................55 � Figure 6-3: Location of proposed water quality monitoring sites associated with dredging activities.........58 � Figure 6-4: Location of proposed water quality monitoring sites associated with disposal activities..........59 � Figure 6-5: Telemetry based loggers and associated probes........................................................................60
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Table 1-1 Overview of management and monitoring commitments associated with the Project
No Reference Commitment Responsibility Reporting Recipient Timing
Water Quality and Benthic Primary Producer Management
1 Section 5.1.2
Section 5.2.2
Section 5.3.2
Use of suitable dredging plant and equipment to minimise turbidity. Dredge Contractor
Dredge Vessel Log
PHPA During dredging
2 Section 5.1.2
Section 5.2.2
Section 5.3.2
Maintaining calibration of the hydrographic survey systems onboard the dredge. Dredge Contractor
Dredge Vessel Log
PHPA During dredging
3 Section 5.1.2
Section 5.2.2
Section 5.3.2
Monitoring of weather and sea conditions. Dredge Contractor
Dredge Vessel Log
PHPA During dredging
4 Section 5.1.2
Section 5.2.2
Section 5.3.2
Implementation of the Tiered Monitoring Framework following a water quality breach. PHPA Bi- Monthly Water Quality Monitoring Report
DEC During dredging
5 Section 5.1.2
Implementation of the Routine Water Quality Monitoring Program. PHPA Bi- Monthly Water Quality Monitoring Report
DEC Prior to, during and post dredging
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No Reference Commitment Responsibility Reporting Recipient Timing
6 Section 5.1.2
Implementation of the Routine Surface Sediment Profiling Monitoring Program. PHPA Pre and Post Dredging (surface sediment profiling)
DEC Prior to, during and post dredging
7 Section 5.2.2
Section 5.3.2
Undertake the Reactive Coral Health Investigation and Reactive Mangrove Health Monitoring Program.
PHPA Reactive Mangrove Health Monitoring Report
DEC On exceedance of water quality/ sedimentation trigger levels
Marine Fauna
8 Section 5.4.2
Procedures for marine fauna interaction (including turtles and cetaceans) shall be developed for vessels to reduce the potential impacts to marine fauna. All work-site personnel shall be inducted regarding the proper response to fauna interaction (including unexpected encounters).
PHPA Marine Fauna Interaction Plan
Dredge Contractor
Prior to commencement of dredging
9 Section 5.4.2
Before commencement of dredging operations and offshore spoil disposal, a 15 minute visual inspection of the monitoring zone using binoculars from a high observation platform on the vessel must be undertaken by a person trained in faunal observation and distance estimation.
Dredge Contractor
Dredge Vessel Log
PHPA Prior to commencement of dredging
10 Section 5.4.2
Where turtles, dugongs or cetaceans are observed within a 150 m radius of the dredge and are likely to be injured due to dredging, dredging must not commence until all individuals are observed to move outside the monitoring zone or have not been sighted for 20 minutes, or the dredge is to move to another area of the dredge site to maintain a minimum distance of 300 m between the dredger and any marine species.
Dredge Contractor
Dredge Vessel Log
PHPA During dredging and disposal
11 Section 5.4.2
Where turtles, dugong or cetaceans are observed within a 500 m radius of the hopper barge at Spoil Ground I, disposal of dredge material must not commence until all individuals are observed to move outside the monitoring zone of have not been sighted for 20 minutes, or the dredge is to move to another area of the dredge site to maintain a minimum distance of 300 m between the dredger and any marine species.
12 Section 5.4.2
Dredging activities will be ceased if a significant marine mammal or reptile is sighted within the ’monitoring zone’ of 150 m radius around the dredge and 500 m around the hopper
Dredge Contractor
Dredge Vessel Log
PHPA During dredging and disposal
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No Reference Commitment Responsibility Reporting Recipient Timing
barge at Spoil Ground I.
13 Section 5.4.2
Equipment and vessels shall operate in accordance with appropriate industry and equipment standards including specifications for noise levels. Regular maintenance will be conducted to the manufacturer’s specifications. Equipment covers, mufflers and other noise suppression equipment shall also be maintained and in good working order at all times.
Dredge contractor
Dredge Vessel Log
PHPA During dredging and disposal
14 Section 5.4.2
The use of thrusters and excessively noisy equipment will be avoided wherever practicable and engines, thrusters and auxiliary plant will not be left in ‘stand by’ or ‘running’ mode unnecessarily
Dredge Contractor
Dredge Vessel Log
PHPA During dredging and disposal
15 Section 5.4.2
Where practicable, vessel loading and unloading in nearshore areas shall be conducted during daylight hours. Where this is not practicable, artificial lighting shall be reduced to the minimum required for safe operations.
Dredge contractor
Regular Auditing
PHPA During dredging and disposal
16 Section 5.4.2
Outside artificial lighting on vessels will be kept to a minimum (i.e. navigational lights and where safety dictates necessary deck lighting). Lighting should be switched off when not in use and automatic timers/sensors installed where possible. Only necessary artificial lights shall be used.
Dredge contractor
Regular Auditing
PHPA During dredging and disposal
17 Section 5.4.2
The construction workforce and all vessels will be limited to designated areas. Recreational boating, fishing, diving, spear-fishing, fossicking, (i.e. collecting shells and any other biological or natural material e.g. animal’s bones), will be prohibited from designated construction areas during the Project.
Dredge Contractor
NA NA During dredging and disposal
18 Section 5.4.2
PHPA shall report any detected mortality of any listed EPBC marine species to DSEWPaC and the DEC within 24 hours of observation.
PHPA Incident Reporting
DSEWPaC / DEC
During dredging and disposal
Introduced Marine Pests
19 Section 5.5.2
Comply with AQIS (Australian Quarantine Inspection Service) requirements, State and Federal legislation for dredge vessels/barges.
Dredge Contractor
Dredge Vessel Log (Ballast water)
PHPA Prior to dredging
20 Section 5.5.2
Any vessels coming to Port Hedland for the Project from overseas or domestically that carry ballast or entrained water are required to follow one of two mandatory AQIS requirements:
• Option 1 – full exchange of ballast water outside of Australian waters;
• Option 2 – assess risk status of ballast water, considering the location of uptake and time of year. If it is deemed to be high risk, ballast water must be managed in
Dredge Contractor
Dredge Vessel Log (Ballast water)
PHPA Prior to dredging
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No Reference Commitment Responsibility Reporting Recipient Timing
accordance with the requirements of the National System for the Prevention and Management of Marine Pest Incursions.
21 Section 5.5.2
Any vessels coming to Port Hedland for the Project from overseas or domestically should be subject to a biofouling risk assessment following guidance within the National Biofouling Management Guidance for Non-Trading Vessels document. Vessels assessed as posing a risk should be inspected to ensure they are free of biofouling and preferably dry-docked for cleaning and repair/renewal of the antifouling system immediately prior to departure for Australia.
Dredge Contractor
Dredge Vessel Log
PHPA Prior to dredging
22 Section 5.5.2
All areas where mud and sediments can collect, including anchor and chain lockers and hoppers, should be inspected and cleaned prior to a vessel’s departure for Port Hedland. Anchor chains, cables, and other gear that has been deployed overboard should also be inspected and cleaned of any attached or entangled marine growth. These procedures should be repeated prior to departure from Port Hedland to prevent translocation of species away from this region.
Dredge Contractor
Dredge Vessel Log
PHPA Prior to and after completion of dredging and disposal
Hydrocarbon Management
23 Section 5.6.2
Hydrocarbon spills will be managed in accordance with the requirements of PHPA’s Marine Oil Pollution Management Plan.
Dredge Contractor
Oil Spill Incident Report
PHPA During dredging and disposal
24 Section 5.6.2
Vessels: tanks and machinery shall be equipped with measurement and overflow protection (i.e. flow and level meters, relief valves, overflow protection valves and emergency shut-off).
Dredge Contractor
NA NA Prior to and during dredging
25 Section 5.6.2
Industry standards, port authority and pollution prevention regulations shall be adhered to during:
• Refuelling;
• Transfer;
• Storage; and
• Handling of hazardous materials (e.g. bunding, level gauges, overflow protection, drainage systems and hardstands).
Dredge Contractor
Regular Auditing
PHPA During dredging and disposal
26 Section 5.6.2
Volumes of stored fuels and chemicals will be limited to day-use. Use of appropriately licensed mini-tankers for refuelling.
Dredge Contractor
Regular Auditing
PHPA During dredging and disposal
27 Section 5.6.2
Hydrocarbons (including hydrocarbon wastes) shall be stored in appropriately labelled drums or tanks and in bunded areas that can contain 110% of material stored within.
Dredge Contractor
Regular Auditing
PHPA During dredging and disposal
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No Reference Commitment Responsibility Reporting Recipient Timing
28 Section 5.6.2
Equipment will be designed and operated to prevent spills and leaks through the provision of in-built safeguards such as relief valves, overflow protection, and automatic and manual shut-down systems.
Dredge Contractor
Regular Auditing
PHPA During dredging and disposal
29 Section 5.6.2
Establish comprehensive vessel refuelling procedures to avoid or reduce the possibility of a release include as a minimum the requirements for:
• adhering to all port authority and pollution regulations;
• refuelling during daylight hours where possible, depending on sea conditions;
• refuelling within established safety boundaries and during weather/sea/visibility conditions that will minimise potential release risk;
• training personnel involved with refuelling or fuel transfer in their roles, functions and responsibility, including emergency response;
• maintaining open communication channels;
• deploying spill prevention systems in accordance with established procedures and regulatory requirements; and
• maintaining emergency response equipment to ensure that it is readily available.
Dredge Contractor
Regular Auditing
PHPA During dredging and disposal
30 Section 5.6.2
All personnel will be familiar with the use of oil spill clean up kits and dispose of waste in the prescribed manner.
Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
Waste Management
31 Section 5.7.2
Controlled wastes shall be managed as per the Environmental Protection (Controlled Waste) Regulations 2004 (WA).
Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
32 Section 5.7.2
Chemicals carried in packaged, solid or bulk form will comply with the regulations of Part A of SOLAS Chapter VII and the IMDG Code regarding the classification, packing, marking, labelling and placarding, documentation, stowage, handling and emergency response action of dangerous goods.
Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
33 Section 5.7.2
All waste designated as hazardous/dangerous requiring disposal shall be packaged, stored and transported in accordance with IMDG (International Maritime Dangerous Goods) requirements. Vessel documentation shall include Material Safety Data Sheets (MSDS’) for each substance carried.
Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
34 Section All vessels will comply with the compulsory insurance and insurance certificate Dredge Regular PHPA Ongoing during
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No Reference Commitment Responsibility Reporting Recipient Timing
5.7.2 requirements of the International Convention on Liability and Compensation for Damage in Connection with the Carriage of Hazardous and Noxious Substances (HNS) by Sea 1996.
Contractor Auditing dredging and disposal
35 Section 5.7.2
Vessels of 24 m or more in length but less than 400 gross tonnage engaged in international voyages will carry a Declaration on Antifouling Systems (prohibiting the use of harmful organotins in antifouling paints) in compliance with the International Convention on the Control of Harmful Antifouling Systems on Ships.
Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
36 Section 5.7.2
All sewage and grey water treatment systems shall be frequently checked, maintained and monitored to ensure systems are efficient, fully operational and discharging treated water in accordance with MARPOL 73/78 Convention Annex IV (sewage) and Annex V (garbage).
Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
37 Section 5.7.2
No residues containing noxious substances will be discharged within 12 nm of the nearest land mass, in compliance with MARPOL 73/78 Convention Annex II.
Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
38 Section 5.7.2
Waste management requirements shall be communicated to personnel (i.e. through inductions, pre-starts and/or Job Hazard Analyses (JHAs)).
Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
39 Section 5.7.2
Communition systems on vessels shall be capable of handling the volumes generated and maintained regularly so they efficient and fully operational at all times.
Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
40 Section 5.7.2
Solid and liquid wastes and hazardous materials shall be stored in appropriately labelled drums or tanks.
Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
41 Section 5.7.2
Hazardous substances handling is to be carried out by suitably trained personnel only. Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
42 Section 5.7.2
Incompatible products will not be stored together. Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
43 Section 5.7.2
Empty liquid waste containers shall be segregated from other wastes and stored in designated areas.
Dredge Contractor
Regular Auditing
PHPA Ongoing during dredging and disposal
44 Section Incidents of waste entering the marine environment to PHPA as soon a possible (but within Dredge Regular PHPA Ongoing during
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No Reference Commitment Responsibility Reporting Recipient Timing
5.7.2 48 hours) and implement appropriate clean up procedures Contractor Auditing dredging and disposal
Offshore Spoil Ground Management
45 Section 5.8.2
It will be established by GPS that, immediately prior to disposal, the vessel is within the approved Spoil Ground I boundary.
Dredge Contractor
Dredge Vessel Log
PHPA During disposal
46 Section 5.8.2
Each load of dredged material will be dumped so that dumped material is distributed evenly within the approved Spoil Ground I boundary.
Dredge Contractor
Dredge Vessel Log
PHPA During disposal
47 Section 5.8.2
Any dredge or barge used in connection with disposal activities and any associated towing vessels must comply with the relevant state, national and/or international standards with respect to seaworthiness, safety and environmental requirements, or any rules or conditions laid down by the certifying classification society, and be capable of disposing the dredge material at the disposal ground.
Dredge Contractor
Regular Auditing
PHPA During disposal
48 Section 5.8.2
The volume of dredged material (in cubic metres) dumped at Spoil Ground I will be estimated and compared daily to the disposal quantities.
Dredge Contractor
Dredge Vessel Log
PHPA During disposal
49 Section 5.8.2
Regular progress surveys will be recorded and compared to the approved disposal quantities.
Dredge Contractor
Dredge Vessel Log
PHPA During disposal
50 Section 5.8.2
Maintaining calibration of the hydrographic survey systems onboard the dredge. Dredge Contractor
Dredge Vessel Log
PHPA During disposal
51 Section 5.8.2
Monitoring of weather and sea conditions. Dredge Contractor
Dredge Vessel Log
PHPA During disposal
52 Section 5.8.2
Implementation of the Tiered Monitoring Framework following a water quality trigger breach. PHPA Routine Water Quality and Reactive Coral Health Monitoring
PHPA During disposal
Dredge Material Management Area Management
53 Section 5.9.2
Implementation of the Tiered Monitoring Framework following a water quality trigger breach. PHPA Monitoring report
DEC Bi Monthly or on exceedance of adopted
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No Reference Commitment Responsibility Reporting Recipient Timing
trigger levels
54 Section 5.9.2
Material proposed for use for the construction of the earth bunds surrounding the DMMAs will not be sourced unless a detailed soil assessment is conducted and the proposed material does not contain PASS.
PHPA Assessment Report
DEC Prior to bund construction
55 Section 5.9.2
Monitoring of the DMMA discharge to ensure it meets the action criteria outlined in Dewatering Effluent and Groundwater Monitoring Guidance For Acid Sulphate Soil Areas (DEC 2006b). Total Titratable Acidity (TTA), Electrical Conductivity (EC) and pH will be monitored weekly to ensure that water quality parameters are maintained at a pH > 6 and a TTA < 40 mg/L.
PHPA Assessment Report
DEC During DMMA development and onshore disposal
56 Section 5.9.2
Regular watering of unsealed roads, exposed surfaces, active construction areas and stockpiles.
Shore based Contractor
Regular Auditing
PHPA During onshore disposal
57 Section 5.9.2
Restriction of vehicle movements and vehicle speeds to reduce dust emissions and impacts to terrestrial fauna.
Shore based Contractor
Regular Auditing
PHPA During onshore disposal
58 Section 5.9.2
Use of environmentally safe dust suppressants. Shore based Contractor
Regular Auditing
PHPA During onshore disposal
59 Section 5.9.2
General housekeeping practices to ensure that there is no accumulation of waste materials within the construction site that may generate dust.
Shore based Contractor
Regular Auditing
PHPA During onshore disposal
60 Section 5.9.2
Staff induction program to ensure all employees are made aware of the need to minimise dust generation.
Shore based Contractor
Regular Auditing
PHPA During onshore disposal
61 Section 5.9.2
Reporting of any community complaints regarding dust levels. Shore based Contractor
Incident Report
PHPA During onshore disposal
62 Section 5.9.2
A noise management plan will be developed in order to undertake construction activities, in accordance with the Environmental Protection (Noise) Regulations 1997.
Shore based Contractor
Regular Auditing
PHPA Prior to commencement of Project
63 Section 5.9.2
Construction activities to be managed according to weather conditions and proximity to noise sensitive areas to minimise impact or noise and vibration emissions.
Shore based Contractor
Regular Auditing
PHPA During onshore disposal
64 Section 5.9.2
Regular monitoring and maintenance of plant and equipment so that it remains in good working condition and noise emissions are kept to a minimum.
Shore based Contractor
Regular Auditing
PHPA During onshore disposal
65 Section 5.9.2
Use of appropriate design during construction of the DMMA B-North and G, including configuration, landforming of berms and localised use of vegetative screening where applicable. The DMMA G bund walls directly adjacent to Finucane Road will be partially
Shore based Contractor
Regular Auditing
PHPA During onshore disposal
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No Reference Commitment Responsibility Reporting Recipient Timing
vegetated using vegetation suitable to the characteristics of the area
66 Section 5.9.2
Vegetation screening and landscaping to reduce visibility of the DMMAs will be considered. The height of the DMMAs will not exceed +12 m AHD.
Shore based Contractor
Regular Auditing
PHPA During onshore disposal
67 Section 5.9.2
All equipment and vehicles shall be washed down prior to arrival to Project site areas in order to minimise the spread of weeds.
Shore based Contractor
Regular Auditing
PHPA During onshore disposal
68 Section 5.9.2
Surface water run-off from the DMMA’s will be contained where appropriate and discharge controlled such that there are no significant, physical off-site impacts.
Shore based Contractor
Regular Auditing
PHPA During onshore disposal
1
Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
1. INTRODUCTION
1.1 Project Overview
The Port Hedland Port Authority (PHPA) proposes to expand port infrastructure in Port Hedland.
Specifically, the PHPA proposes the development of eight berths in South West Creek, a tributary of
the Port Hedland Inner Harbour estuary. The development includes dredging and associated onshore
and offshore disposal of dredge material. Figure 1-1 and Figure 1-2 shows the proposed dredge
footprint and onshore and offshore disposal areas.
Five of the eight planned berths have been allocated to three Developers, with three berths currently
unallocated (Figure 1-1):
• Berth AP4: Fortescue Metals Group (FMG);
• Berths SP3 and SP4: Northwest Iron Ore Alliance (NWIOA);
• Berths SP1 and SP2: Roy Hill Infrastructure (RHI); and
• Berths AP5, AP6 and AP7: Unallocated.
Due to the size and nature of the proposed works, environmental approvals are required under both
State and Commonwealth environmental legislation. The concept of the port development in South
West Creek, including the dredging campaign and associated land based infrastructure is known as
the South West Creek Dredging and Reclamation Project (referred to hereafter as the ‘Project’).
Dredging and disposal is to be undertaken using two types of dredges and with a combination of
offshore and onshore disposal of dredge material as described below:
Backactor dredges: Initial dredging of both Potential Acid Sulfate Soil (PASS) and non-PASS material to
a nominal depth of -6.0 m CD (chart datum) with the dredge material transported via split hopper
barges to an offshore disposal ground in Commonwealth waters1 (Figure 1-2). It is proposed using two
backactor dredges for the South West Creek dredging campaign, at times working concurrently
depending on available access depth to South West Creek, which will change as dredging progresses.
Offshore disposal of dredge material removed by the backactors within the Department of
Sustainability, Environment, Water, Population and Communities (DSEWPaC), (formerly the
Department of Environment, Water, Heritage and the Arts (DEWHA)), previously approved Spoil
1 Note a separate Sea Dumping Permit for dredge spoil disposal in Commonwealth waters was applied for on
the 25th
August 2010.
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
Ground I. Material from the dredge footprint will be transferred from the dredge footprint to this
disposal ground via split hopper barges.
Cutter Suction Dredge: Dredging of deeper non-PASS material from nominally -6.0 m CD down to
design depth, pumping the dredged material onshore to five designated Dredge Material
Management Areas (DMMAs) (Figure 1-3).
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
� Figure 1-1: Dredge footprint including intertidal disturbance corridor, layout of berths and turning circle
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
� Figure 1-2: Location of Spoil Ground I
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
� Figure 1-3: Location of Dredge Material Management Areas (DMMAs)
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
1.2 Project Location
Port Hedland is located approximately 1660 km north of Perth within the Pilbara region of Western
Australia. The Port of Port Hedland is defined as ‘water within a radius of 10 nautical miles (nm) off
Hunt Point Beacon (Beacon 47)’ (PHPA 2001) and is managed by PHPA under the Port Authorities Act
1999 (WA). The port consists of a 20 nm dredged channel leading to a dredged basin between Nelson
Point and Finucane Island, where several intertidal creeks converge. The harbour has been highly
modified by dredging activities, and development and operation of port related industry.
The Project is located adjacent to the existing inner harbour area of Port Hedland, in South West
Creek. The site is a tidal creek, with current seabed levels ranging from 0.0 to -4.0 m CD. The site is
sheltered but experiences fast tidal currents as a result of the high tidal range experienced in the
region.
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
1.3 Aim of the Plan
This Dredging Management Plan (DMP) covers the proposed environmental management and
monitoring of dredging of 14.2 Mm3 of material from South West Creek and disposal of this volume
offshore to Spoil Ground I and onshore DMMA’s.
The aim of this DMP is to provide a framework for the environmental management of the dredge
program in a manner that achieves the requirements of the Project specific environmental objectives
as detailed within the EPA State Referral Document (herein referred to as ‘the Referral Document’).
The DMP has been prepared for inclusion in the State Environmental Referral Document (ERD) for the
Project and addresses the following:
• management strategies that will be adopted to mitigate risks associated with the dredging
program (Section 5);
• provision of a management framework to enable PHPA and its contractors to monitor, assess
and mitigate impacts upon local/regional environmental values from dredging (Section 6.1);
and
• details the monitoring programs to be undertaken during dredging, and contingency actions
to be implemented following exceedance of nominated trigger values (Section 6).
The finalised DMP will address the requirements of applicable State and Commonwealth Referral
Assessment Decisions and the Commonwealth Sea Dumping Permit (SDP) in addition to comments
from PHPA and relevant stakeholders. This will be finalised prior to the commencement of the dredge
program.
1.4 Key Environmental Legislation/Standards/Guidelines
1.4.1 Commonwealth Legislation
The applicable Commonwealth legislation relevant to the Project’s activities described within this
DMP include, but are not limited to, the following:
Environment Protection (Sea Dumping) Act 1981
The Environment Protection (Sea Dumping) Act 1981 requires permitting for the dumping of wastes or
any other matter (e.g. dredge material) within Australian marine waters (unless for prescribed
purposes e.g. reclamation). A Sea Dumping Permit application was submitted to DSEWPaC on
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
20 August 2010, who are currently reviewing the application with a decision expected on
26 November 2010.
Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)
The EPBC Act establishes a process for the assessment and approval of proposed actions that are
likely to have a significant impact on matters of national environmental significance or on
Commonwealth land. Possible impacts on endangered species or listed migratory species may trigger
the Act. Previous dredging projects undertaken within Port Hedland Inner Port area have been
deemed an uncontrolled action. The Project has been referred to DSEWPaC (Reference Number: EPBC
2010/5678) under the EPBC Act and the decision on the assessment is expected on 9 November 2010.
Other relevant Commonwealth legislation includes:
• Environment Protection (Sea Dumping) Regulations 1983;
• Australian Quarantine Requirements 2000; and
• Australian Ballast Water Management Requirements 2001.
1.4.2 State Legislation
The applicable State legislation relevant to the Project’s activities described within this DMP includes,
but is not limited to, the following:
Environmental Protection Act 1986 (WA) (EP Act)
Part IV of the EP Act defines the procedures and approvals process of environmental impact
assessment required for proposed developments. Part V of the EP Act establishes a range of
statutory instruments to permit the assessment and management of environmental outcomes arising
from emissions from industry.
Wildlife Conservation Act 1950 (WA)
The Wildlife Conservation Act 1950 provides for the protection of listed fauna. Potential impacts on
Specially Protected species or Priority species are given weighted consideration in the State EIA
process under the EP Act.
Biosecurity and Agricultural Management Act 2007 (WA)
The Biosecurity and Agricultural Management Act (2007) seeks to establish a modern biosecurity
regulatory scheme to prevent serious animal and plant pests and diseases from entering the State
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
and becoming established, and to minimise the spread and impact of any that are already present
within the State, and is therefore relevant to the control of introduced marine pests.
Other State legislation includes:
• Pollution of Waters by Oil and Noxious Substances Act 1987;
• Conservation and Land Management Act 1994;
• Fish Resources Management Act 1994;
• Marine and Harbours Act 1981;
• Shipping and Pilotage Act 1967;
• Environmental Protection Regulations 1986; and
• Pollution of Waters by Oil and Noxious Substances Regulations 1983.
1.4.3 Relevant Standards and Guidelines
The key applicable standards and guidelines relevant to the Project’s activities described within this
DMP include, but are not limited to, the following:
1.4.3.1 Commonwealth
National Assessment Guidelines for Dredging 2009 (Commonwealth)
The National Assessment Guidelines for Dredging (NAGD) (Commonwealth of Australia 2009) provide
a framework for the environmental impact assessment and permitting of the ocean disposal of
dredged material.
Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC/ARMCANZ
2000)
The Australian and New Zealand Guidelines for Fresh and Marine Water Quality
(ANZECC/ARMCANZ 2000) provide guidance for activities operating within state waters that may
affect water quality. These guidelines provide criteria for establishing levels of ecological
protection for marine areas based on existing levels of disturbance, but also recommend
deferring to locally developed consultative guidelines where they exist.
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
1.4.3.2 State Guidelines
EPA Environmental Assessment Guideline No.3 (EAG 3)
The Environmental Assessment Guideline No. 3 (EAG 3) (EPA 2009) specifically applies to
development projects that are predicted to result in irreversible loss of or serious damage to marine
benthic primary producer habitat (BPPH). This guideline defines and recognises the fundamental
ecological importance of BPP and their habitats (BPPH), and provides a framework for assessing
environmental impacts on BPPH. The risk-based spatial assessment framework provides the means
for evaluating cumulative losses (i.e. historical and proposed losses) of BPPH within defined sub-
ecosystem areas called local assessment units (LAUs).
Cumulative loss guidelines (CLGs) are based on six categories of marine ecological protection, which
the proponent must apply in the assessment of ecological risks to BPPH associated with a proposal.
The EPA (2001) designated a Port Hedland Industrial Area Management Unit as the appropriate
management unit for mangrove and other BPP communities in the Port Hedland Harbour region. The
Port Hedland Industrial Management Unit covers an area of 4,977 ha and has been termed ‘Category
F’ under EAG 3 (EPA 2009) following calculation of previous loss estimates associated with projects
and additional of BPPH through changes in accretion and erosion factors effecting the management
unit.
EPA Guidance Statement No. 1 (EAG 1)
EPA Guidance No. 1 (Protection of Tropical Arid Zone Mangroves along the Pilbara Coastline) (EAG 1)
(EPA 2001), categorises Port Hedland as being covered by ‘Management Area 4: Other mangrove
areas—Inside designated industrial areas and associated port areas’. These are all mangrove areas
that occur inside areas that have been designated as industrial areas, associated ports or other
development and not covered by EAG 3.
The EPA's operational objective for ‘Management Area 4’ is that the impacts of development on
mangrove habitat and ecological function of the mangroves in these areas should be reduced to the
minimum practicable level. The EPA would consider the significance of the environmental impacts but
would expect that the projects in these zones are likely to be capable of being made environmentally
acceptable.
Pilbara Coastal Water Quality Consultation Outcomes: Environmental Values and Environmental
Quality Objectives
The Pilbara Coastal Water Quality Consultation Outcomes: Environmental Values and Environmental
Quality Objectives (DoE 2006) report recommended a set of Environmental Values (EVs) (Table 1-1)
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
and associated Environmental Quality Objectives (EQOs) for the State’s marine waters from Exmouth
to Cape Keraudren, developed through consultation with stakeholders and communities.
Four levels of ecological protection (LEPs) are linked to the EQO for maintenance of ecosystem
integrity, which protects the EV of Ecosystem Health. Each LEP has corresponding environmental
quality conditions (limits of acceptable change in contaminant concentrations and biological
parameters) stipulated (Table 1-2).
� Table 1-1: Pilbara coastal waters environmental values and environmental quality objectives
Environmental Value (EV)
Environmental Quality Objective
Environmental Quality Criteria
Management Strategies
Ecosystem Health (ecological value)
This means maintaining the structure (e.g. the variety and quantity of life forms) and functions (e.g. the food chains and nutrient cycles) of marine ecosystems.
Impacts on water and sediment quality are maintained within the ANZECC/ARMCANZ (2000) guidelines.
There is no introduction of marine pest species.
Section 5.1 – Marine Water Quality
Section 5.2 – Mangrove Habitats
Section 5.3 – Other Marine Habitats (non-mangroves)
Section 5.4 – Marine Fauna
Section 5.5 – Introduced Marine Species
Section 5.6 – Hydrocarbon Management
Section 5.7 – Waste Management
Section 5.8 – Offshore Spoil Ground Management
Section 5.9– Onshore Dredge Material Management
Water quality is safe for recreational activities in the water (e.g. swimming).
Recreational and Aesthetics (social use value)
Aesthetic values of the marine environment are protected.
Impacts on recreational boating and aesthetic values of the marine environment will be minimal.
Section 5.1 – Marine Water Quality
Section 5.6 – Hydrocarbon Management
Section 5.7 – Waste Management
Section 5.9– Dredge Material Management
Cultural and Spiritual (social use value)
Cultural and spiritual values of the marine environment are protected.
Impacts on cultural and spiritual values of the marine environment will be minimal.
Section 18 application approved 2009. Refer to application for further management.
Fishing and Aquaculture (social use value)
Seafood (caught or grown) is of a quality safe for eating
Water quality is suitable for
Relevant criteria from national Food Standards code.
Water quality maintained within the
Section 5.1 – Marine Water Quality
Section 5.5 – Introduced Marine Species
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
Environmental Value (EV)
Environmental Quality Objective
Environmental Quality Criteria
Management Strategies
aquaculture purposes ANZECC/ARMCANZ (2000) guidelines.
Section 5.6 – Hydrocarbon Management
Section 5.7 – Waste Management
Industrial Water Supply (social use value)
Water quality is suitable for industrial supply purposes.
N/A – industry do not use Port Hedland harbour waters for water supply.
N/A
Source: Pilbara Coastal Water Quality Consultation Outcomes: Environmental Values and
Environmental Quality Objectives (DoE 2006).
� Table 1-2: Pilbara coastal waters levels of ecological protection linked to the maintenance of ecosystem integrity
Environmental Quality Condition
(Limit of acceptable change) Level of Ecological
Protection Contaminant concentration indicators Biological indicators
Maximum No contaminants ─ pristine No detectable change from natural variation
High Very low levels of contaminants No detectable change from natural variation
Moderate Elevated levels of contaminants Moderate changes from natural variation
Low High levels of contaminants Large changes from natural variation
Source: Pilbara Coastal Water Quality Consultation Outcomes: Environmental Values and
Environmental Quality Objectives (DoE 2006).
1.5 PHPA Environmental Policy
Port Hedland Port Authority is committed to the protection of the environment and the minimization
of impacts of port activities on the environment. This is achieved through responsible environmental
management, the incorporation of the environment into all decision making and planning and the
continual improvement of all environmental performance (Appendix 1).
1.6 Stakeholder Consultation
Stakeholder consultation has formed an integral role in the planning and design stages of the Project.
PHPA has undertaken extensive consultation with representatives from local community groups,
relevant local and state government bodies, local indigenous groups and neighbouring industry.
Consultation was undertaken based on the Community Consultation Guideline (DEC 2006). The
following parties were identified as key stakeholders with a significant interest in the Project:
Roy Hill Iron Ore Pilbara Native Title Service
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
Fortescue Metals Group (FMG)
North Western Iron Ore Alliance (NWIOA)
Environmental Protection Authority Services Unit
(EPASU)
Care For Hedland Environment Group
Town Of Port Hedland
Local Aboriginal Groups
Department of Sustainability, Environment,
Water, Population and Communities (DSEWPaC
(formerly DEWHA))
Department of Environment and Conservation
(DEC),
The results of the consultation are detailed in the Environmental Referral Document (ERD) and have
been taken into account in the development of the management strategies identified within this
DMP.
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
2. ROLES AND RESPONSIBILITIES
The proponent, PHPA, is responsible for the implementation of the proposal and adherence to the
commitments made within the DMP. Table 2-1 identifies the responsibilities associated with the key
management positions during the life of the Project.
� Table 2-1 Positions and responsibilities of key personnel associated with the Project
Position Responsibilities
Project Manager Overall responsibility for implementation of the DMP.
Overall responsibility for complying with all relevant legislation, standards and guidelines.
Ensures dredging activities are conducted in a safe environment to both site personnel and the public.
Dredge Contractor
Prepares and implements an environmental management plan in accordance with the requirements of the DMP.
Implements the management actions of the DMP.
Ensures adequate training of all staff within area of responsibility.
Ensures all equipment is adequately maintained and correctly operated.
Environmental Superintendent
Comply with the requirements of the DMP.
Provides advice on dredging and dredge material management related environmental issues.
Overseas implementation of environmental controls, monitoring programs, inspections and audits.
Completes compliance reporting requirements.
Coordinates the training and induction process.
Responsible for the implementation of the environmental monitoring programs and inspections.
Prepares environmental monitoring reports.
Provides advice with respect to environmental issues as required.
All persons involved in project Comply with the requirements of the DMP.
Comply with all legal requirements under the approvals documents and relevant Acts.
Exercise a Duty of Care to the environment at all times.
Report all environmental incidents
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
3. PROJECT DESCRIPTION
Port Hedland Port Authority (PHPA) is seeking approval under the EP Act (WA) to undertake dredging
within South West Creek, adjacent to existing facilities. The expansion project includes dredging of
approximately 14.2 million cubic metres (Mm³) of marine sediment from South West Creek, to enable
the construction of eight berths and a turning circle (Figure 1-1). The berths will accommodate vessels
with a ship size of up to 300 m in length by 50 m width.
The dredging operation will involve excavation by two backacter dredges of approximately 8.8 Mm3 of
material above -6.0 m CD depth with disposal of this material offshore using hopper barges. Dredging
of the remaining 8.7 Mm3 material below -6.0 m depth will be undertaken by a cutter suction dredge
(CSD) and this material will be disposed onshore to five designated DMMAs, of which two already
exist and one is approved. Two new DMMAs are proposed for the Project, as shown in Figure 1-3.
The key parameters for the Project are summarised in Table 3-1 and coordinates of the proposed
dredge footprint, Spoil Ground I and the DMMAs are provided in Table 3-2.
� Table 3-1: Key parameters of the Project
Element Description
No of Berths (dredging) Eight (SP1-SP4, AP4, AP5, AP6 and AP7)
Dredge footprint Approximately 116 ha
Total dredge volume Approximately 14.2 Mm3
Offshore dredge spoil disposal component
Current seabed down to -6.0 m CD
Approximately 5.5 Mm³
Overall onshore dredge spoil disposal component (reclamation)
From -6.0 m CD to design depth
Approximately 8.7 Mm³
Expected date of commencement of dredging
Second quarter of 2011
Duration of dredging Approximately 2.7 years (if undertaken continuously to completion)
Duration onshore disposal Approximately two years
Area of land disturbance for onshore disposal
DMMA G: 134 ha
DMMA B-North: 81 ha
Corridors (for access and pipelines): 9 ha
Total: 224 ha
DMMA perimeter bund height No more than +12.0 m AHD (Australian Height Datum)
Area of mangrove clearance Closed canopy mangroves: 31.5 ha
Scattered mangroves: 8.5 ha
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
3.1 Proposed Dredge Footprint
Specifically, the proposed dredging campaign at South West Creek comprises:
• Dredging of berth pockets SP1 and SP2 to -19.0 m CD and SP3, SP4 and AP4 to -19.3 m CD;
• Dredging of berth pockets AP5, AP6, AP7, the departure channel and the 400 m turning circle
to -14.8 m CD;
• Dredging of a 200 x 200 m area adjacent to the turning basin to -21 m CD which will act as a
silt trap;
• Extending the existing Inner Harbour departure channel into South West Creek adjacent to
the berths to a design depth of -14.8 m CD to enable safe departure of loaded vessels;
• Batters at 1:10 for marine muds (i.e. from 0.0 up to +6.0 m CD) and 1:2.5 for the deeper
consolidated material below 0 m CD; and
• Associated over-dredging of approximately 0.7 m due to dredging tolerances and siltation
protection.
The proposed dredge footprint is shown in Figure 1-1, including the total area to be disturbed by
dredging activities (approximately 112 ha). This area is indicated as the disturbance envelope and
includes the top of the dredge batters. A 20 m corridor on the outside of the dredge footprint has
been set to capture future land based construction disturbance. Calculations based on this outer
corridor the dredge footprint and future construction footprint is approximately 116 ha.
3.2 Offshore Disposal
The proposed spoil ground (Spoil Ground I) has previously been used for disposal of dredged
sediments from within Port Hedland Harbour. Since 2001 PHPA have been granted two previous
permits to undertake maintenance dredging of locations within Port Hedland Inner Harbour. PHPA
currently has a current permit (SD2007/0342) that covers maintenance dredging in for 2007, 2010
and 2013 totalling a dredge volume of 1.75 Mm3 to dispose at Spoil Ground I. An application for a sea
dumping permit has been lodged with the Department of Sustainability, Environment, Water,
Pollution and Communities (DSEWPaC) for offshore disposal of all dredged material (down to -6.0 m
CD).
Dredge material will be transferred to either self propelled or towed, split hull hopper barges, for
transportation to Spoil Ground I (11 km offshore) (Figure 1-2). It is anticipated that a single dredging
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
and disposal ‘cycle’ (loading, transport, disposal of dredged material and return of barge to dredge
area) will take approximately four hour round trip. Given the relatively large distance to and from the
spoil ground, it is proposed that up to three split hopper barges, each with a holding capacity of
3,200 m3 of material, will be used. On arrival at the disposal ground the barges will manoeuvre to the
selected site for dumping. Disposal of the material will be achieved by opening the split hopper to
allow the dredged material to be released from the hopper. The barge will then immediately sail back
to the dredging area to repeat the cycle.
3.3 Dredge Material Management Areas
In order to effectively manage the dredged material for land disposal five onshore Dredge Material
Management Areas (DMMAs) have been identified for the South West Creek Development, all
located within the PHPA UDP Development Areas A, B and G (PHPA 2009). Two are existing DMMAs,
one currently holds approval under Part IV, and approvals are sought for the remaining two in this
ERD. The DMMAs are shown in Figure 1-3 and described below:
• DMMA A and B are located to the south of Anderson Point. Both DMMAs are existing dredge
material management areas and were used as a disposal ground for dredged material arising
from FMG’s third berth at Anderson Point (Figure 1-3);
• DMMA B-south is located to the south of DMMA B, and approvals under Section IV have
already been obtained by FMG (WA EPA Ministerial Conditions 771) (Figure 1-3);
• Proposed DMMA G is located to the south of South West Creek and east of the BHPBIO rail
line (Figure 1-3); and
• Proposed DMMA B-north situated north of the existing DMMA B (Figure 1-3).
The material to be disposed of onshore will be dredged by a CSD and pumped to land via pipelines.
(Figure 3-1) The material will consist of both coarse and fine material. While the coarse material will
settle out of suspension rapidly and constitute valuable material for the Mining Companies to use for
onshore construction projects, the fines have the potential to stay in suspension for prolonged
periods (‘slimes’). Generation of significant quantities of slimes is a well known characteristic of
dredging in Port Hedland, and settlement ponds will be required for the fines to sufficiently settle
prior to discharge of the return water into the creek systems.
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
� Figure 3-1: Cutter Suction Pipelines at DMMA H as part of BHPBIO RGP6 Expansion (BHPBIO 2009)
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
� Table 3-2 Coordinates of relevant project infrastructure (GDA94 Z50)
Dredge footprint coordinates Spoil Ground I Coordinates DMMA A Coordinates DMMA B Coordinates DMMA G Coordinates DMMA B North Coordinates DMMA B South Coordinates
Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude Longitude Latitude
118° 34' 25.37" E 20° 19' 30.27" S 118º 35' 21.80" E 20º 11' 26.97" S 118º 34' 9.80" E 20º 20' 34.80" S 118º 33' 52.47" E 20º 21' 54.17" S 118º 33' 1.34" E 20º 20' 9.45" S 118º 34' 22.78" E 20º 21' 32.71" S 118º 33' 48.58" E 20º 22' 13.26" S
118° 34' 18.40" E 20° 19' 44.31" S 118º 35' 23.04" E 20º 12' 31.36" S 118º 34' 9.73" E 20º 20' 35.18" S 118º 34' 1.73" E 20º 21' 14.89" S 118º 33' 11.09" E 20º 20' 11.44" S 118º 34' 20.78" E 20º 21' 32.73" S 118º 33' 52.46" E 20º 21' 54.21" S
118° 34' 10.39" E 20° 19' 55.74" S 118º 34' 15.42" E 20º 12' 32.53" S 118º 34' 1.73" E 20º 21' 14.89" S 118º 34' 12.71" E 20º 21' 16.80" S 118º 33' 0.51" E 20º 20' 51.95" S 118º 34' 12.71" E 20º 21' 16.80" S 118º 33' 52.47" E 20º 21' 54.17" S
118° 34' 3.82" E 20° 20' 8.14" S 118º 34' 12.41" E 20º 11' 27.04" S 118º 33' 52.47" E 20º 21' 54.17" S 118º 34' 20.78" E 20º 21' 32.73" S 118º 33' 8.38" E 20º 20' 54.10" S 118º 34' 1.72" E 20º 21' 14.91" S 118º 34' 8.25" E 20º 21' 54.47" S
118° 34' 0.14" E 20° 20' 18.04" S 118º 35' 21.80" E 20º 11' 26.97" S 118º 33' 52.46" E 20º 21' 54.21" S 118º 34' 22.78" E 20º 21' 32.71" S 118º 33' 2.48" E 20º 21' 16.66" S 118º 34' 24.49" E 20º 20' 55.68" S 118º 34' 17.21" E 20º 21' 47.20" S
118° 33' 51.66" E 20° 20' 17.12" S 118º 33' 48.59" E 20º 22' 13.18" S 118º 34' 30.53" E 20º 21' 28.07" S 118º 33' 5.05" E 20º 21' 22.41" S 118º 34' 37.15" E 20º 20' 55.30" S 118º 34' 19.25" E 20º 21' 48.30" S
118° 33' 39.28" E 20° 20' 12.98" S 118º 33' 36.00" E 20º 22' 6.57" S 118º 34' 31.60" E 20º 21' 29.26" S 118º 33' 7.61" E 20º 21' 27.13" S 118º 34' 39.07" E 20º 20' 55.24" S 118º 34' 46.16" E 20º 22' 0.19" S
118° 33' 33.29" E 20° 20' 7.98" S 118º 33' 37.04" E 20º 22' 2.77" S 118º 34' 30.45" E 20º 21' 30.47" S 118º 33' 8.89" E 20º 21' 30.08" S 118º 34' 44.85" E 20º 20' 49.90" S 118º 34' 30.43" E 20º 22' 31.23" S
118° 33' 40.67" E 20° 19' 58.22" S 118º 33' 32.59" E 20º 22' 0.53" S 118º 34' 29.31" E 20º 21' 31.66" S 118º 33' 11.91" E 20º 21' 33.46" S 118º 34' 45.88" E 20º 20' 51.22" S 118º 33' 54.06" E 20º 22' 12.64" S
118° 33' 50.28" E 20° 19' 46.64" S 118º 33' 35.90" E 20º 21' 43.02" S 118º 34' 23.33" E 20º 21' 34.50" S 118º 33' 16.08" E 20º 21' 36.97" S 118º 34' 41.55" E 20º 20' 55.16" S 118º 33' 50.86" E 20º 22' 14.43" S
118° 33' 59.02" E 20° 19' 36.72" S 118º 33' 32.27" E 20º 21' 42.42" S 118º 34' 22.53" E 20º 21' 36.07" S 118º 33' 18.71" E 20º 21' 33.78" S 118º 34' 41.17" E 20º 21' 15.30" S 118º 33' 48.58" E 20º 22' 13.26" S
118° 34' 7.67" E 20° 19' 24.66" S 118º 33' 30.27" E 20º 21' 39.27" S 118º 34' 25.29" E 20º 21' 41.58" S 118º 33' 19.91" E 20º 21' 36.58" S 118º 34' 28.01" E 20º 21' 25.79" S
118º 33' 27.63" E 20º 21' 35.12" S 118º 34' 19.25" E 20º 21' 48.30" S 118º 33' 18.16" E 20º 21' 38.73" S 118º 34' 30.53" E 20º 21' 28.07" S
118º 33' 25.35" E 20º 21' 24.03" S 118º 34' 17.21" E 20º 21' 47.20" S 118º 33' 19.05" E 20º 21' 39.48" S 118º 34' 22.78" E 20º 21' 32.71" S
118º 33' 28.60" E 20º 21' 4.91" S 118º 34' 8.25" E 20º 21' 54.47" S 118º 33' 16.30" E 20º 21' 55.35" S
118º 33' 25.16" E 20º 20' 56.71" S 118º 33' 52.47" E 20º 21' 54.17" S 118º 33' 7.37" E 20º 21' 50.23" S
118º 33' 25.58" E 20º 20' 48.08" S 118º 33' 4.05" E 20º 21' 48.33" S
118º 33' 36.62" E 20º 20' 44.26" S 118º 33' 0.89" E 20º 21' 46.29" S
118º 33' 38.21" E 20º 20' 38.19" S 118º 32' 57.88" E 20º 21' 43.94" S
118º 33' 47.59" E 20º 20' 30.35" S 118º 32' 55.19" E 20º 21' 41.16" S
118º 34' 9.83" E 20º 20' 34.64" S 118º 32' 52.96" E 20º 21' 38.51" S
118º 34' 9.80" E 20º 20' 34.80" S 118º 32' 50.42" E 20º 21' 35.13" S
118º 32' 48.34" E 20º 21' 31.44" S
118º 32' 46.73" E 20º 21' 27.16" S
118º 32' 45.89" E 20º 21' 21.55" S
118º 32' 45.52" E 20º 21' 16.81" S
118º 32' 45.64" E 20º 21' 12.22" S
118º 32' 46.22" E 20º 21' 8.07" S
118º 33' 1.34" E 20º 20' 9.45" S
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
4. STUDIES AND PREDICTED IMPACTS
The environmental factors that have been assessed for the Project were identified through existing
studies, other published information and consultation with DEC, EPA, DSEWPaC and other
stakeholders. The following table summarises PHPA’s evaluation of each the environmental factors,
potential environmental impacts, proposed management measures to reduce the environmental risk
and proposed monitoring to be undertaken are presented in Table 4-1.
� Table 4-1 Summary of identified impacts, management and risk associated with the Project
Factor Potential Impact Proposed Management Measures
Increased turbidity and sedimentation above predicted levels as a result of dredging and disposal activities.
See Section 5.1.2, 5.8.2 and 5.9.2
Water Quality
Changes to physio-chemical water quality parameters as a resulting of dredging and disposal activities.
See Section 5.1.2
Direct impact on mangrove communities at beyond that predicted within the dredge footprint and Spoil Ground I.
See Section 5.1.2, 5.2.2 and 5.9.2
Marine Habitat (mangroves)
Indirect impact to mangrove communities, beyond that predicted, as a result of increased turbidity and sedimentation.
See Section 5.1.2, 5.2.2 and 5.9.2
Other Marine Habitat (non mangroves)
Direct habitat loss from physical disturbance beyond that predicted within the direct impact areas within the dredge footprint and Spoil Ground I.
See Section 5.1.2, 5.3.2, 5.8.2 and 5.9.2
Impacts upon marine fauna as a result of underwater noise from vessel movements and the dredge vessel.
See Section 5.4.2
Direct impacts to marine fauna as a result of accidental hydrocarbon spills.
See Section 5.4.2 and 5.6.2
Vessel collision with marine fauna. See Section 5.4.2
Disorientation of marine turtles or seabirds as a result of artificial light spill.
See Section 5.4.2
Marine Fauna
Impacts as a result of benthic habitat loss associated with increased levels of turbidity and sedimentation.
See Section 5.1.2, 5.2.2, 5.3.2, 5.4.2, 5.8.2 and 5.9.2
Introduction of marine organisms to the waters of Port Hedland Port as a result of entrainment in internal vessel systems originating from national or international waters, and associated environmental impacts.
See Section 5.5.2 Introduced Marine Species
Introduction of marine organisms to the waters of Port Hedland Port through ballast water/vessels.
See Section 5.5.2
Potential Acid Sulphate Soils
Generation of acid sulphate soils associated with the oxidation of sulphides in soils following exposure to the atmosphere
See Section 5.9.2
Terrestrial Flora and Fauna
Disturbance of listed flora species/ habitats that could potential cause impacts to fauna species
See Section 5.7.2 and 5.9.2
Dust Management Impacts aesthetically and to human health from mobilisation of dust into the atmosphere
See Section 5.9.2
Hydrocarbon Management
Impacts to marine fauna and habitat following an hydrocarbon spill during dredging and disposal
See Section 5.6.2
Waste Impacts to marine water quality, mangroves, fauna, recreation and aesthetic values as a result of spills and leaks of hazardous
See Section 5.7.2
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
Factor Potential Impact Proposed Management Measures
chemicals. Management
Impacts to the surrounding environment, marine flora and fauna from toxicity and ingestion as a result of incorrect management or disposal of solid and liquid wastes.
See Section 5.7.2
4.1 Water Quality
Port Hedland is located on the confluence of five shallow ephemeral creek systems that provide
occasional freshwater inflows into the port area following sporadic rainfall events. During these
periods it is likely that the water quality in port limits would experience substantial physical and
chemical variation due to impacts from catchment run off, particularly from contaminants that enter
the catchment from urbanised areas located to the south east of the port.
Several baseline water quality investigations have been undertaken within port limits, predominantly
associated with proposed capital dredging and reclamation activities.
The most applicable data was collected from two locations within South West Creek between
December 2009 and June 2010 (WorleyParsons 2010). Summary statistics for pH, dissolved oxygen,
turbidity, salinity and temperature for South West Creek undertaken by WorleyParsons are provided
below in Table 4-2.
� Table 4-2 Summary of water quality recorded in South West Creek between December 2009 and May 2010 (WorleyParsons 2010) –Bolded values represent exceedance of adopted AZNZECC ARMCANZ guidelines.
Temperature (°C) pH
Salinity (ppt)
Turbidity (NTU)
DO (% saturation)
ANZECC/ARMCANZ (2000) N/A 8-8.4 N/A 20 90% (lower limit)
Mean 28.59 8.0 38.50 25.99 88.67
Median 30.03 7.9 41.52 15.20 91.90
80th percentile 31.62 8.1 45.60 34.10 99.90
Standard Error 0.05 0.0 0.15 0.57 0.23
Several contaminant investigations have bee undertaken in Port Hedland waters. Generally
contaminants have been within adopted guidelines except for elevated metal species copper, lead
and zinc (Hope Downs Management Services 2002), (Port Hedland Port Authority 2003). To support
this information a range of chemical parameters were tested for bi monthly from identical locations
to that of the physicochemical water quality program (WorleyParsons 2010) within South West Creek.
No significant spatial or temporal differences (p<0.05) were identified for all sampled nutrient
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
parameters (ammonia, NOx, TKN, P, TOC, chlorophyll a), metals or hydrocarbons analysed. All
parameters reported concentrations below ANZECC/ARMCANZ 99% species protection guidelines
except for cobalt and copper concentrations (HPPL 2008).
4.1.1 Sediment Plume Modelling
Sediment plume modelling was undertaken to define impacts to water quality during dredging and
offshore disposal. Both TSS and sediment deposition were modelled from dredging activities within
South West Creek and from disposal activities within Spoil Ground I. A Delft3D hydrodynamic and
dredge plume model developed by Deltares in the Netherlands was used to model increases in TSS
and sedimentation associated with the proposed Project (Cardno, 2010). Disposal activities at Spoil
Ground I were modelled using an advanced sediment fate model – Suspended Sediment FATE
(SSFATE).
The dredge and onshore disposal campaign was simulated as a non-stop dredging and disposal
campaign with commencement in the second quarter of 2011 and a duration of 2.7 years. The
disposal of material offshore was modelled for a period of 15 months between November 2010 and
February 2011.
The overall dredge and disposal campaign was divided into seven phases, detailing the number and
type of dredges engaged concurrently and the associated disposal method (offshore or onshore).
Several scenarios were modelled to reflect changes to water quality during dredging and disposal in
summary:
• One or two backacter dredges removing the upper sediment layers down to a depth of -6.0 m
CD with associated offshore disposal using hopper barges
• One large CSD dredging from -6.0 m CD down to the design depth with associated disposal
into four onshore DMMAs.
• Changes to TSS concentrations and sediment deposition associated with the disposal of
dredge material within Spoil Ground I;
• Average and exceedances 5% of the time were modelled for TSS concentrations and sediment
deposition within the inner port area; and
• TSS concentrations from two water depths within the inner harbour, surface and bottom
were modelled to define differences in TSS concentrations between different layers of water.
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
During disposal activities maximum TSS concentrations of 100 mg/L were recorded within the disposal
ground footprint. Maximum concentrations predicted for outside the disposal ground footprint were
<10 mg/L as a result of plume migration from point of disposal (Figure 4-1). For ambient conditions
(50th Percentile) TSS concentrations within Spoil Ground I did not exceed 5 mg/L and the sediment
plume did not extend outside the proposed spoil ground boundary (Figure 4-2).
Higher TSS values within the inner port area are consistently predicted in bottom waters compared to
the surface layer during all phases of dredging. Figure 4-3 shows various TSS contours for 5% of the
time in surface and bottom waters, respectively, during each phase of the dredging and onshore
disposal campaign. Peaks in TSS are likely to be confined to South West and South creek with TSS
values ranging between 20 and 35 mg/L associated with surface and bottom water respectively.
Average TSS concentrations did not exceed 15 mg/L during the most dredge intensive phases of the
project (Figure 4-4).
Sediment deposition modelled for the entire dredge program displayed a maximum of 100,000 g/m2
within Spoil Ground I (Figure 4-5). While deposition was mainly focused within the footprint of Spoil
Ground I, deposition up to 100,000 g/m2 is also predicted outside the disposal ground to the north
west in response to driving tidal currents. Conversion of this total deposition amount equates to a
rate of 0.017 g/cm2/d.
Sedimentation within the dredge footprint indicates sedimentation will likely exceed 60 mm within
the proposed dredge footprint, however some of this material would be dredged during successive
dredging phases. Sedimentation will likely reach up to 60 mm near the location of the water
discharge in South Creek and South West Creek, respectively and 15 mm within the upper reach of
South West Creek and within the south part of Port Hedland Harbour (Figure 4-6).
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
� Figure 4-1: TSS (mg/L) Predicted for Energetic Conditions (95th
percentile) at Spoil Ground I
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
� Figure 4-2: TSS (mg/L) predicted for ambient conditions (50th
percentile) at Spoil Ground I
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
A B
� Figure 4-3 TSS (mg/L) predicted for 5% of the time in surface waters (A) bottom waters (B) (mg/L) during phase B to G (note phase A is not shown due to low and uniform TSS concentration across the creek system of les than 5 mg/L)
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
A
� Figure 4-4: Average TSS concentration (mg/L) in surface (A) and bottom (B) waters during phase B to G (note phase A is not shown due to low and uniform TSS concentration across the creek system of les than 5 mg/L)
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
� Figure 4-5: Sedimentation (g/m2) deposited within and adjacent to the Spoil Ground I over the dredge program
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Port Hedland Port Authority South West Creek Dredging Approvals - Draft Dredging Management Plan
A B
� Figure 4-6: Predicted cumulative sediment deposition in mass (g/m2) (A) and thickness (mm) (B) at the end of each phase B to G simulations (note: Phase A is not shown due to low predicted sedimentation)
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Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
4.1.2 Mobilisation of Contaminants
4.1.2.1 Offshore Disposal
A detailed sediment quality assessment was undertaken in South West Creek for sediments identified
for offshore disposal. Background levels of contaminants were all below NAGD screening levels with
the exception of nickel and chromium. These two metals have both been found to occur at naturally
elevated concentrations throughout the Port Hedland region (DEC 2006). While concentrations for
nickel and chromium were above screening levels at several locations within the dredge footprint the
95% UCL concentration calculated for chromium and nickel was below the NAGD screening levels. In
accordance to the NAGD sediments within the dredge footprint are therefore considered suitable for
offshore disposal and dredging is not expected to cause any contamination release from disturbed
sediments.
4.1.2.2 Onshore Disposal
Two recent geotechnical studies have been undertaken within the South West Creek dredge footprint
for the screening of potential contaminants of sediments designated for onshore disposal.
Metal concentrations were compared against Ecological Investigation Levels (EILs) found within the
Assessment Levels for Soil, Sediment and Water (DEC 2003) and ANZECC/ARMCANZ
(ANZECC/ARMCANZ 2000) Interim Sediment Quality Guidelines (ISQG) guidelines, respectively. Both
sets of guidelines are often used to determine the suitability of sediments for onshore disposal
activities and/or reclamation.
All samples displayed metal concentrations below the relevant guideline levels, with the exception of
nickel and chromium. Nickel concentrations were below the EIL guideline but above the ISQG
guideline for several samples. One sample displayed a chromium concentration above the ISQG
guideline but below the EIL guideline. Further testing was undertaken to determine potential
bioavailability during dredging and disposal of these two contaminants. All elevated samples returned
elutriate concentrations below adopted guidelines once a suitable dilution factor was applied to
reflect discharge conditions during dewatering activities.
Sediments sampled in 2010 were also assessed for the potential generation of acid sulfate soils (ASS)
during dredging and onshore disposal. Of the samples collected below -6.0 m CD only one sample
identified as potential ASS (PASS). Given that the remainder of samples displayed no evidence of
PASS, the mixing of sediments during dredging and onshore disposal would alleviate the potential for
ASS generation due to mixing with material that displayed no PASS.
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Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
4.2 Mangroves
4.2.1 Direct Impacts
The South West Creek Project will result in the direct loss of 39.94 ha of mangrove. These losses are
comprised of 26.19 ha due to the South West Creek dredging footprint and disturbance envelope, and
13.75 ha due to the construction of the DMMAs and temporary pipeline and access corridors.
Using mangrove assemblage classifications described by Semeniuk (2007), and adopted by
WorleyParsons (2010) during the baseline mangrove community investigation, the breakdown of
direct loss of mangroves is predicted to be as follows:
• 25.36 ha of Avicennia marina scrub
• 8.44 ha of Avicennia marina open heath
• 3.14 ha of Rhizophora stylosa scrub
• 2.99 ha of Rhizophora stylosa low forest.
The EPA (2001) designated a Port Hedland Industrial Area Management Unit as the appropriate
management unit for mangrove and other BPP communities in the Port Hedland Harbour region. The
threshold of cumulative loss for Category E (Development Areas) is 10%, which is applicable to this
management unit. The predicted losses of 39.94 ha due to the South West Creek Project would
increase cumulative losses to 6.00%, which is below the EPA’s (2009) cumulative loss guideline of
10%. Approximately 79% of direct losses due to the South West Creek Project will be low forest and
scrub mangrove community types (closed canopy communities; A. marina and R. stylosa dominated).
The remaining direct losses will be A. marina open heath (scattered mangroves). Low forest and scrub
community types are considered to have higher ecological function than the open forest community
types.
4.2.2 Indirect Impacts
Mangrove communities within the predicted sediment plume are at risk from sediment deposition
through smothering of pneumatophores that assist with the plants respiration. The potential impacts
to mangrove communities from the effects of sedimentation during dredging are discussed in detail in
Section 7.2.4 of the Referral Document. A review of literature identified that the tolerance level of
mangrove species identified in the area predicted to be influenced by the dredge plume are unlikely
to experience adverse effects from sedimentation as sediment thickness levels will exceed a tolerance
limit of 100 mm during dredging (Figure 4-6).
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Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
The South West Creek Project has the potential to affect the hydrodynamics within mangrove
communities in the Project Area. Hydrodynamic modelling was undertaken to assess changes to
intertidal inundation regimes and bed shear stress. Model results from a selection of locations in
South West Creek and the wider creek system show that no significant changes in levels of inundation
within intertidal mangrove habitat is expected due to the change in bathymetry associated with
dredging. While construction of bund walls for DMMA B-North and DMMA G is likely to restrict the
tidal excursion at Highest Astronomical Tide, no indirect loss of mangrove habitat is predicted.
4.3 Other BPPH
4.3.1 Dredge Footprint and Onshore Disposal Areas
The majority of the lower intertidal and subtidal benthic habitats within Port Hedland Port are
characterised by unvegetated substrate (78.77%), with sparse patches of turf algae, small foliaceous
macroalgae and sessile filter feeding invertebrates (Sinclair Knight Merz 2009). A canopy algae
community of a Sargassum sp. exists in dense patches in the eastern creeks of Stingray Creek. No
seagrass communities have been found in the harbour.
Habitats supporting coral communities are sparsely distributed and do not represent a high percent
cover across the Inner Harbour (0.09% cover). Three sparse small colonies of low diversity and
coverage coral communities exist within South West Creek, South East Creek and Stingray creek that
comprise of (BHPBIO 2009a).
Mangrove habitats tend to be replaced by salt marsh with increasing distance from the shoreline and
eventually by bare tidal flats as sediments become dryer and more saline. Salt marsh communities
primarily comprise halophytic (salt tolerant) herbaceous plants such as the samphire species,
Tecticornia halocnemoides and Tecticornia indica. Cyanobacterial mats have also been identified as
occurring within these communities that develop sporadically under certain conditions.
The extensive supratidal mudflats located in the Port Hedland area are interspersed by low lying
sandy islands that are dominated by Triodia sp. grasslands over open tussock grasslands (Biota
Environmental Sciences 2008).
4.3.1.1 Direct Impacts
Based on recent investigations, the following habitats will be directly removed from within the
proposed dredge footprint during dredging:
• Salt Marsh (including cyanobacterial mats) – 94.2 ha from DMMA G and 45.2 ha from
DMMA B-North;
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Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
• Macroalgae habitat – approximately 10 ha; and
• Soft Coral and Small Algae – 0.19 ha.
4.3.1.2 Indirect Impacts
The Project will not result in any direct removal of coral habitat. However, the dredge and DMMA
discharge plumes are predicted to cause elevated levels of suspended solids and increased
sedimentation rates in the creek systems with the highest levels predicted in South and South West
Creek, as discussed in Section 4.1.
The model predictions on the increase in TSS levels within the creek systems are presented in Section
4.1. The coral community in South West Creek is located on the edge of the predicted plume
influence from dredging, with average increases in TSS of 15-20 mg/L likely to occur during most
phases (Figure 4-4). It is expected that these chronic increases in TSS will have some impact on the
coral community, though the tolerance of the corals located in this tidal mangrove creek is not
known. Cumulative sedimentation in the range of 10-15 mm over the duration of the dredging and
onshore disposal campaign (2.7 years) was also predicted in the vicinity of the South West Creek coral
community (Figure 4-6). Seeing that background sedimentation rates in South West Creek have been
recorded of up to 40 mm/year, the corals in South West Creek may not be significantly impacted by
the dredging although localised sedimentation regime associated with the coral in South West Creek
are currently unknown. The coral communities in South East Creek and Stingray Creek are more likely
to experience low but chronic elevations in TSS in the order of 5 mg/L for the duration of the
campaign (Figure 4-4). Impacts to these coral communities are consequently not considered likely.
Of the three areas of coral habitat located outside the inner harbour area only the eastern tip of
Finucane Island is predicted to be influenced occasionally by elevations in TSS ranging between 1-
5 mg/L 5% of the time. These TSS concentrations are however considered below threshold values that
could impact on these communities.
Potential indirect effects on macroalgae from plumes of turbid water include smothering by particles
which settle out of suspension onto the BPP (sedimentation) and reduction in light due to suspended
particles (turbidity). Benthic macroalgae within the Inner Harbour are adapted to the natural
sedimentation and low light regimes, although tolerance varies between species.
Impacts are expected to be negligible given that these communities comprise sparse patches of turf
algae and foliaceous macroalgae with low diversity and are dominated by fast growing species that
are tolerant to dynamic physical processes of the Inner Harbour.
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Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
4.3.2 Spoil Ground I
4.3.2.1 Direct Impacts
Spoil Ground I is located within the Commonwealth marine area and is an existing spoil ground used
by PHPA, ranging in depth from -8.0 to -13.0 m CD. The spoil ground area does not support any
benthic primary producers of significance due to the lack of available hard substrate for colonisation
by corals and macroalgae, and the shifting nature of the sediments which pose a significant challenge
for colonisation by seagrass (GHD 2007) The majority of biota present within Spoil Ground I is
invertebrate infauna (GHD 2007).
4.3.2.2 Indirect Impacts
While no coral communities have previously been identified within the offshore Spoil Ground I coral
communities have been previously identified 3.5 km to the north at Spoil Ground Reef and 6.5 km to
the north east at Minilya bank. Both reefs support a diverse and abundant community mainly
consisting of Turbinaria spp., with encrusting and massive Porites colonies, Acropora colonies, Faviids,
sponges and christmas tree worms (Spirobranchus giganteus) (URS 2005).
Predicted modelling of dredged material disposal at Spoil Ground I predicts that TSS concentrations
will be limited to <10 mg/L for 5% of the time outside the Spoil Ground I footprint (Figure 4-1). Based
on threshold levels adopted for similar offshore coral monitoring projects no coral loss from elevated
TSS concentrations are expected.
Modelling of sedimentation associated with disposal activities displayed a maximum of 100,000 g/m2
(Figure 4-5) outside Spoil Ground I. Conversion to a daily rate equates to 0.017 g/cm2/d. Comparison
to background sedimentation rates (< 0.1 g/cm2/d) and sedimentation rates that have been shown to
adversely impact corals (0.1 to 0.5 g/cm2/d). Therefore sedimentation deposition associated with the
dredge program will not have impacts on benthic habitats outside the proposed disposal ground
footprint.
4.4 Marine Fauna
Marine fauna have the potential to be impacted through vessel collision, artificial light, underwater
noise. Listed marine fauna species investigations conducted within the Port Hedland region have
previously identified flatback turtle nesting beaches at Cemetery beach, Pretty Pool and Cooke Point
outside the project footprint. Juvenile turtles have previously been identified within the inner harbour
area foraging at the fringe of mangrove communities.
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Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
Port Hedland is not known as an area for aggregation of whales with migration routes further
offshore in waters greater than 20 m depth. Small numbers of dolphins have been identified within
inner port areas although their distribution is considered sparse given the lack of resident
populations. Dugongs have previously been identified within the inner harbour but it is not expected
there is a high risk of interaction due to limited availability of suitable seagrass habitats in the inner
port area.
The impacts to marine fauna species can therefore be considered unlikely given the low abundance of
sensitive marine fauna species previously indentified within Port Hedland.
4.5 Introduction of Marine Pests
The Port is considered at risk of further marine pest outbreaks based on levels of activity and future
development of the Port area. Incursion of these species into the Port area has been via two separate
pathways, release of ballast water from ships and biofouling on vessel hulls. While several introduced
marine pest species have been identified within Port Hedland the number of species is considered low
comparative to the level of port activity.
4.6 Potential Acid Sulfate Soils
Marine PASS materials that have previously been identified in sediments located between 0 and 2m
below the seabed within Port Hedland Inner Port will be dredged and disposed in offshore Spoil
Ground I. Given that the dredge sediments will not dry out or be exposed to the atmosphere during
transfer of material between the dredge footprint and the spoil ground a change in soil pH through
oxidisation would be unlikely. Sediments identified for onshore disposal have been tested in situ and
are considered non PASS. Impacts associated with ASS are considered unlikely.
4.7 Terrestrial Flora and Fauna
The composition of flora and vegetation in the onshore disturbance footprint areas were generally
considered typical of the families and genera frequently recorded in the Pilbara coastal region
namely, samphires and mudflats; Sandy Islands; and Grasslands. No Conservation Significant Flora,
Fauna or SRE Fauna have been recorded in DMMA B North or DMMA G and thirteen conservation
significant fauna were identified as potentially occurring in the DMMAs. The majority of these species
are migratory bird or bat species which may use mangrove and supra-tidal, salt marsh communities
found within each of the DMMA areas proposed for disturbance for foraging, feeding, resting or
breeding.
The scale of the Project has limited potential impacts on terrestrial flora and fauna resulting from
disturbances involved in construction activities. Three other respective DMMA areas will be used
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Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
during the project, namely, DMMA A, B and B South. These DMMA areas were not assessed as part of
this referral given that both DMMA A and B are currently being used to dispose of material and
DMMA B south has been approved to be disturbed by placement of material onshore.
4.8 Dust Management
The Project has the potential to generate dust following drying of marine sediments placed onshore,
during construction activities, principally land clearing, the use of earth moving machinery for bund
wall construction and vehicle and equipment traffic on unsealed roads and laydown areas. Modelling
of dust generated from BHP Billiton’s DMMA H, for the Nelson Point Dredging Program, found that
uncontrolled dust generated from DMMA H would not change the cumulative dust levels predicted at
the Port Hedland Hospital monitoring location (BHPB, 2009 – Dust Assessment). DMMA H is a similar
size, 204 ha, to the new construction footprint required for the South West Creek Dredging Program,
224ha. Consequently there is likely to have a limited and temporal impact on the ambient air quality.
4.9 Hydrocarbon and Chemicals
Hydrocarbons used during the dredging will include diesel and smaller amounts of lubricating oil and
grease for dredging equipment. Diesel is a ‘light oil’ and small spills of 2000-20000 L will usually
evaporate and disperse within a day or less; for larger spills, a residue of up to one-third of the
amount spilled will usually remain after a few days.
Direct contact with diesel can affect marine birds by ingestion during preening and hypothermia from
matted feathers, although the oil evaporates so rapidly that the number of birds affected is usually
small (NOAA 2006). Small spills have the potential for serious impact if they occur close to a large
nesting colony or are transported into an area of large bird population (NOAA 2006). Given that there
unlikely be large seabird colonises only localised impacts are predicted should diesel be spilt.
Land based activities including activities in and around the settlement areas could result in a minor
hydrocarbon spillage. PHPA has recently developed an Marine Oil Pollution Management Plan should
an oil spill occur within the existing port and surrounding areas.
4.10 Waste Management
If not managed appropriately, waste has the potential to impact on human health, pollute the
environment and damage ecological communities. Although vessels are not permitted to discharge
waste such as sewage, bilge water or oily mixtures within the 12 nm limit, accidental discharges of
small quantities of solid or liquid wastes into the marine environment may occur. Accidental
discharges from vessels (not including hydrocarbons and chemicals) could include:
32
Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
• Deck drainage, which may include small amounts of waste material;
• Engine cooling water; and
• Accidental discharge of liquid effluent.
Potential impacts from this project could include:
• Risk of harm or death to wildlife caused by ingestion or entanglement of waste;
• Increase in nutrients and pathogens in the water column (potentially leading to algal blooms
or toxicity); and
• Reduction in Aesthetic value caused by solid waste.
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5. MANAGEMENT IMPLEMENTATION
The dredging and disposal activities require strategies to minimise predicted impacts identified in the
submitted referral document. This section provides the specific management that will be adopted
during the dredge program to ensure predicted and potential impacts do not occur.
5.1 Water Quality
5.1.1 Overview
The generation of a turbid plume is one of the most likely adverse environmental effects associated
with dredging operations. The generation of dredge-induced turbid plumes generally results from the
resuspension of existing fine sedimentary material from the seabed during dredging and mobilisation
during disposal.
Potential impacts from changes in water quality through sedimentation and increases in turbidity
include the smothering of sensitive habitats. Corals can be impacted via smothering from
sedimentation or by reduction in light through the water column. Both pathways cause restrictions to
the corals ability to photosynthesise. Mangroves are impacted through the sedimentation that can
smother pneumatophores which can limit mangrove health by restricting respiration rate.
The potential impacts to water quality include:
• Increased Total Suspended Sediment (TSS) levels – caused by suspended sediments released
into the water column during dredging and resuspended following deposition;
• Increased sedimentation rates – caused by particles settling out of the water column during
dredging and disposal and excess water discharge from DMMAs;
• Acidification of discharge water due to PASS in the dredged material for onshore disposal;
• Mobilisation of potential contaminants through the disturbance of sediments by the dredge,
and through discharge water from the DMMAs;
• Altered physical parameters in the discharge water;
• Construction, operation and completion of activities at DMMAs (refer to dust management
measures outlined in Section 6.6); and
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• Introduction of waste and hydrocarbons into the water from dredges and associated
machinery (refer to hydrocarbon and waste management measures outlined in Section 5.6
and 5.7).
Predictive modelling undertaken to define the extent and level of impact associated with the
proposed dredging and tailwater discharge has identified that the sediment plume and sediment
deposition footprint extends into areas where these communities exist during dredging. An analysis of
the modelling and BPP thresholds indicates the likely extent (of sedimentation and turbidity) to be
reached during dredging will not impact these communities.
5.1.2 Management Actions
Management Area Water Quality
Performance Objective To minimise the generation and migration of turbid plumes during dredging activities and therefore cause no impacts to coral and mangrove communities through sedimentation or increase in turbidity.
Management Actions Installation of a satellite-based vessel monitoring system on the dredge, allowing a track plot analysis to ensure maximum efficiency of the dredging effort and that no dredging occurs outside the required area occurs.
• Use of suitable dredging plant and equipment to minimise turbidity, including well maintained floating pipelines to be utilised to minimise leakage of turbid water during pumping of material to the DMMAs.
• Maintaining calibration of the hydrographic survey systems onboard the dredge.
• Monitoring of weather and sea conditions.
• Implementation of the Tiered Monitoring Framework following a water quality trigger breach in accordance with the monitoring program (Figure 6-1).
• Install the following management measures to control tailwater discharge associated with reclamation:
• Maximise the residence time in the reclamation area to reduce the turbidity plume of the tailwater discharge. Suitable controls (e.g. weir boxes) will be used at the discharge point to control the water level and the rate of discharge.
• Cease dewatering or move tailwater within reclamation cells when turbidity is excessive.
• Regular inspection and maintenance of erosion and sediment control structures particularly following heavy or prolonged rainfall;
• Stabilise uncovered areas of soil promptly; and
• Install scour protection measures such as gabions where scouring is likely to occur.
Monitoring Implementation of the Routine Water Quality Monitoring Program and Reactive Coral Health Investigation (Section 6.2 and 6.3).
Implementation of the Routine Surface Sediment Profiling Monitoring Program and Routine Mangrove Health Monitoring Program (Section 6.4 and Section 6.5, respectively).
Dredge Contractor to monitor the operation on a continual basis and report any incidents that are likely to cause substantial changes to water quality.
Responsibility The Dredge Contractor is responsible for monitoring the dredging, disposal and reclamation operations and undertaking management actions assigned to them.
PHPA is responsible for the implementation of water and sedimentation quality
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Management Area Water Quality
monitoring programs defined in Section 6.2 and Section 6.4.
Reporting Reporting by PHPA in accordance with reporting schedules for monitoring programs detailed in Section 6.6.
Dredge tracking reports shall be provided by the dredging contractor.
Pre and post dredge survey of sediment characteristics (Section 4.1.2)
Results of the in-pipe sampling and vertical PASS profiling and comparisons (Section 6.6).
The Dredge Contractor must complete an environmental incident report and corrective action report as soon as practicable, but within 48 hours of the incident occurring, and forward this to the Environmental Superintendent.
Monitoring reports shall be submitted by PHPA in accordance with the reporting schedule for each program as outlined in the Reporting Schedule (Section 6.6).
Corrective Action Revision of dredging strategy, including potential relocation of the dredge(s) and alterations to operational mode if plumes exceed predicted ranges and are considered to impact upon key sensitive habitats.
Implementation of the Reactive Mangrove Health Monitoring Program and Reactive Coral Health Investigation (Section 6.3 and 6.5)
Notification to DSEWPaC and the DEC, if water quality exceeds the predicted trigger values, for consideration of need for any corrective action.
Relevant References/ Standards
Pilbara Coastal Water Quality Objectives.
ANZECC/ARMCANZ (2000) Water Quality Objectives.
5.2 Mangroves Habitats
5.2.1 Overview
Potential impacts on mangroves associated with the South West Creek Project include:
• Direct loss due to clearing of mangroves within the dredge footprint;
• Removal of mangroves to provide a temporary pipeline corridor running from the dredge to
DMMA G;
• Removal of mangroves from the dredging footprint in two locations to provide land backed
access;
• Indirect impacts due to excessive sedimentation associated with dredging and DMMA
discharge;
• Indirect impacts due to reduced water quality resulting from DMMA discharge water
(toxicants, low pH); and
• Indirect impacts due to changes in inundation regime.
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The South West Creek Project will result in the direct loss of 39.94 ha of mangrove. These losses are
comprised of 26.19 ha due to the South West Creek dredging footprint and disturbance envelope, and
13.75 ha due to the construction of the DMMAs and temporary pipeline and access corridors.
Potential indirect impacts to mangroves from sedimentation will be managed via the Tiered
Management Framework presented in Figure 6-2 and monitoring described in Sections 6.4 and 6.5.
These management measures include both preventative measures to manage sedimentation levels at
the dredging site and DMMAs as well as contingency measures to be implemented in the event
sedimentation levels are found to be unacceptable during the Routine Surface Sediment Profiling
Monitoring (see Section 6.4).
5.2.2 Management of Mangrove Habitats
Management Area Other Mangrove Habitats
Performance Objective To limit the direct or indirect loss of mangroves associated with the dredging and dredged material management activities
Management Actions The following measures are proposed to limit and manage direct loss of mangrove habitat to no more than the approved Project loss:
• Workforce management including briefings and instructions regarding clearing procedures and information on the ecological significance of mangroves in environmental awareness training.
• Prohibiting access into mangrove areas outside the immediate disturbance area.
• Reporting incidents with the potential to impact on mangroves
• Delineation of clearance boundaries through the use of flagging or other suitable techniques prior to site clearing activities to avoid unnecessary disturbance of mangroves.
• Where possible, scrub rolling mangroves rather than removing mangroves to provide maximum opportunity for vegetative recovery along the boundary of the cleared areas.
The following measures that will be implemented for the management of potential impacts to water quality are also relevant to managing indirect impacts to mangrove habitats:
• Installation of a satellite-based vessel monitoring system on the dredge, allowing a track plot analysis to ensure maximum efficiency of the dredging effort and that no dredging outside the required area occurs.
• Use of suitable dredging plant and equipment to minimise turbidity and sedimentation.
• Maintaining calibration of the hydrographic survey systems onboard the dredge.
• Monitoring of weather and sea conditions.
• Implementation of the Tiered Monitoring Framework following a water quality trigger breach in accordance with the monitoring program (Figure 6-2).
• Install the following management measures to control sedimentation from the tailwater discharge associated with reclamation:
o Suitable controls (e.g. weir boxes) will be used at the discharge point to control the water level and the rate of discharge.
o Regular inspection and maintenance of erosion and sediment
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Management Area Other Mangrove Habitats
control structures particularly following heavy or prolonged rainfall.
Monitoring Monitoring to assist in the management of potential impacts on mangroves:
• Routine Surface Sediment Profiling Monitoring Program (Section 6.4);
• Routine Mangrove Health Monitoring Program (Section 6.5).
Responsibility The Dredge Contractor is responsible for monitoring the dredging and onshore disposal operations and undertaking management actions assigned to them.
PHPA is responsible for the implementation of monitoring programs defined in Section 6.
Reporting Any direct disturbance outside of the approved footprint will be reported and investigated as per regulatory and PHPA requirements;
Results from coral health survey as specified in Section 6.5.3 including analysis of comparison to baseline and reference data
Corrective Action Revision of dredging strategy, including potential relocation of the dredge(s) and alterations to operational mode if sedimentation exceeds predicted ranges and are considered to impact upon mangrove habitat.
Notification to the DEC, if water quality exceeds the predicted trigger values, for consideration of need for any corrective action.
Implementation of Reactive Mangrove Health Monitoring Program.
Relevant References/Standards
Environmental Assessment Guideline 3: Protection of Benthic Primary Producer Habitats in Western Australia's Marine Environment. Perth, WA, Environmental Protection Authority.
Guidance for the Assessment of Environmental Factors (in accordance with the Environmental Protection Act 1986).
Guidance Statement No. 1 for the protection of tropical arid zone mangroves along the Pilbara coastline.
5.3 Other Marine Habitats (non-mangroves)
5.3.1 Overview
The primary causes of seabed disturbance resulting from dredging and disposal activities include the
physical removal or burial of habitats and their associated faunal communities. Potential indirect
impacts due to turbidity and sedimentation will be managed via the water quality management
measures described in Section 5.1. These management measures include both preventative measures
to maintain water quality at the dredging and reclamation site and contingency management
measures to be implemented in the event water quality levels are found to be unacceptable during
the regular water quality monitoring program (see Figure 6-1).
5.3.2 Management of Marine Habitats (non-mangroves)
Management Area Other Marine Habitats (non-mangroves)
Performance Objective Limit the direct loss of intertidal BPPH and sub-tidal BPPH associated with the dredging and dredged material management activities; and
Minimise indirect impacts to intertidal and sub-tidal BPPH resulting from the dredging and dredged management activities.
Management Actions The following measures that will be implemented for the management of potential
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Management Area Other Marine Habitats (non-mangroves)
impacts to water quality are also relevant to managing indirect impacts to mangrove habitats:
• Installation of a satellite-based vessel monitoring system on the dredge, allowing a track plot analysis to ensure maximum efficiency of the dredging effort and that no dredging outside the required area occurs
• Use of suitable dredging plant and equipment to minimise turbidity and subsequent sedimentation.
• Maintaining calibration of the hydrographic survey systems onboard the dredge.
• Monitoring of weather and sea conditions.
• Implementation of the Tiered Monitoring Framework following a water quality trigger breach in accordance with the monitoring program (6.1).
Monitoring Monitoring to assist in the management of potential impacts on benthic habitats (other than mangroves).
Routine Water Quality Monitoring Program (Section 6.3).
Routine Surface Sediment Profiling Monitoring Program (Section 6.4).
Reactive Coral Health Monitoring Investigation (Section 6.3).
Responsibility The Dredge Contractor is responsible for monitoring the dredging and onshore disposal operations and undertaking management actions assigned to them.
PHPA is responsible for the implementation of monitoring programs defined in Section 6.
Reporting Any direct disturbance outside of the approved Project dredge footprint and disposal ground will be investigated by PHPA and reported to the relevant regulatory authorities.
Results from coral health survey as specified in Section 6.2.5 including analysis of comparison to baseline and reference data.
Corrective Action Revision of dredging strategy, including potential relocation of the dredge(s) and alterations to operational mode if turbidity plumes and sedimentation levels exceed predicted ranges and are considered to impact upon BPPH.
Notification to DSEWPaC and the DEC, if water quality exceeds the predicted trigger values, for consideration of need for any corrective action.
Implementation of Reactive Coral Health Monitoring Investigation.
Relevant References/Standards
Environmental Assessment Guideline 3: Protection of Benthic Primary Producer Habitats in Western Australia's Marine Environment. Perth, WA, Environmental Protection Authority. Environmental Protection Authority (2009).
Guidance for the Assessment of Environmental Factors (in accordance with the Environmental Protection Act, 1986). Environmental Protection Authority (2001).
Guidance Statement No. 1 for protection of tropical arid zone mangroves along the Pilbara coastline.
5.4 Marine Fauna
5.4.1 Overview
The presence of vessels during construction may increase the likelihood of a direct collision with
marine fauna, particularly marine mammals and turtles. Turtles are vulnerable to boat strike while
surfacing to breathe or as a startle response to dredging noise or visual cues. They are also vulnerable
to collision with boat propellers in shallow water, where there is little clearance between the keel and
the benthos.
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Surface strikes to marine mammals and turtles by barges travelling to and from the disposal area
could occur during the proposed dredging operation. The number of barges and the abundance of
fauna moving within or through the area will influence the frequency of strikes and the consequence
(proportion of the local/regional population affected). Due to the relatively low speed of the barges
when travelling to and from the disposal area (≤ 12 knots) and the low numbers of fauna likely to
come into contact with vessels, the risk of vessel strike is low.
Lighting sources during dredging activities will include work lights, safety lights, navigational lights and
vessel lighting. Turtle hatchlings use lighting cues when they hatch and move down the beach to the
waters edge. Some forms of artificial lighting have been found to disorientate hatchlings and reduce
their ability to access the sea following hatching. The impacts associated with disorientation of turtle
hatchlings are unlikely given the large distance between the dredge footprint and marine turtle
nesting beaches. Altered underwater light conditions in inshore waters may also change the levels of
predation upon turtle hatchlings, by attracting fish and other predators.
Dredging activities that have the potential to impact marine fauna from underwater noise (e.g.
whales, turtles, dugongs) may range from non-injurious effects (e.g. acoustic annoyance; mild tactile
detection or physical discomfort) to varying levels of injury (i.e. non-lethal and lethal injuries). The
Project however will unlikely cause additional underwater noise impacts during dredging and
operation as the scale of shipping and vessel noise will be at a scale of magnitude less than current
shipping activities within the existing port areas. During support vessels to dredging operations will be
used compared with several shipping vessels movements that currently operate within the existing
port daily.
5.4.2 Management of Marine Fauna
Management Area
Marine Fauna
Performance Objective
To maintain the abundance, species diversity, geographic distribution and ecological functions of marine faunal communities are avoided or minimised through mitigation
To protect EPBC Act listed threatened and migratory species and Specially Protected (Threatened) Fauna consistent with the provisions of the Wildlife Conservation Act 1950.
Management Actions
Vessel Collisions or Entrapment:
• Procedures for marine fauna interaction (including turtles and cetaceans) shall be developed for vessels to reduce the potential impacts to marine fauna.
• All work-site personnel shall be inducted regarding the proper response to fauna interaction (including unexpected encounters).
The Dredge Contractor shall appoint an individual on each vessel to be responsible for undertaking marine fauna observations for the following:
• Before commencement of dredging operations and offshore spoil disposal, a 15 minute visual inspection of the monitoring zone using binoculars from a high observation platform on the vessel must be undertaken by a person trained in faunal observation and distance estimation.
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Management Area
Marine Fauna
• Where turtles, dugongs or cetaceans are observed within a 150 m radius of the dredge and are likely to be injured due to dredging, dredging must not commence until all individuals are observed to move outside the monitoring zone or have not been sighted for 20 minutes, or the dredge is to move to another area of the dredge site to maintain a minimum distance of 300 m between the dredger and any marine species.
• Where turtles, dugong or cetaceans are observed within a 500 m radius of the hopper barge at Spoil Ground I, disposal of dredge material must not commence until all individuals are observed to move outside the monitoring zone of have not been sighted for 20 minutes, or the dredge is to move to another area of the dredge site to maintain a minimum distance of 300 m between the dredger and any marine species.
• The construction workforce and all vessels will be limited to designated areas. Recreational boating, fishing, diving, spear-fishing, fossicking, (i.e. collecting shells and any other biological or natural material e.g. animal’s bones), will be prohibited during the Project.
The monitoring zone is defined as a 150 m radius around the backacter dredge and CSD and a 500 m radius around the hopper barge at Spoil Ground I.
Underwater Noise:
• Equipment and vessels shall operate in accordance with appropriate industry and equipment standards including specifications for noise levels. Regular maintenance will be conducted to the manufacturer’s specifications. Equipment covers, mufflers and other noise suppression equipment shall also be maintained and in good working order at all times.
• Dredging activities will be ceased if a significant marine mammal or reptile is sighted within the ’monitoring zone’ of 150 m radius around the dredge and 500 m around the hopper barge at Spoil Ground I.
• The use of thrusters and excessively noisy equipment will be avoided wherever practicable and engines, thrusters and auxiliary plant will not be left in ‘stand by’ or ‘running’ mode unnecessarily.
Artificial Lighting:
• Where practicable, vessel loading and unloading in nearshore areas shall be conducted during daylight hours. Where this is not practicable, artificial lighting shall be reduced to the minimum required for safe operations.
• Outside artificial lighting on vessels will be kept to a minimum (i.e. navigational lights and where safety dictates necessary deck lighting). Lighting should be switched off when not in use and automatic timers/sensors installed where possible.
• Only necessary artificial lights shall be used. ‘Unnecessary lighting’ includes lighting in unused areas, decorative lighting or lighting that is brighter than needed.
Monitoring Marine Fauna Observations:
• Before commencement of dredging operations and offshore spoil disposal, a 15 minute visual inspection of the monitoring zone using binoculars from a high observation platform on the vessel must be undertaken by a person trained in faunal observation and distance estimation.
• Where turtles, dugongs or cetaceans are observed within a 150 m radius of the dredge and are likely to be injured due to dredging, dredging must not commence until all individuals are observed to move outside the monitoring zone or have not been sighted for 20 minutes, or the dredge is to move to another area of the dredge site to maintain a minimum distance of 300 m between the dredger and any marine species.
• Where turtles, dugong or cetaceans are observed within a 500 m radius of the hopper barge at Spoil Ground I, disposal of dredge material must not commence until all individuals are observed to move outside the monitoring zone of have not been sighted for 20 minutes, or the dredge is to move to another area of the dredge site to maintain a minimum distance of 300 m between the dredger and any marine species.
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Management Area
Marine Fauna
• Monitor light spill during dredging.
Responsibility The Dredge Contractor is responsible for implementation of management actions.
The Dredge Contractor is responsible for maintaining all equipment to ensure underwater noise levels are kept to a minimum. All incidents associated with elevated noise that could cause impacts to marine fauna should be reported to PHPA Environment Manager.
Reporting The Dredge Contractor must report any turtle, dugong or cetacean injury or mortality immediately to the Environmental Superintendent.
The Environmental Superintendent will then notify the PHPA Environment Manager.
PHPA shall report any detected mortality of any EPBC marine species listed to DSEWPaC and the DEC within 48 hours of observation.
Monitoring reports shall be submitted by PHPA to DSEWPaC and the DEC in accordance with the reporting schedule.
Corrective Action Revision of dredging strategy, including potential relocation of the dredge(s) and alterations to operational mode.
Notification to DSEWPaC and the DEC, if water quality exceeds the predicted trigger values, for consideration of need for any corrective action.
Relevant References/ Standards
The Australian National Guidelines for Whale and Dolphin Watching (Department of Environment and Heritage 2006).
5.5 Introduced Marine Species
5.5.1 Overview
The increase in the number of vessel movements associated with dredging and construction could
represent an increased threat of exposure to introduced marine species. The introduction of non-
indigenous species could lead to irreversible detrimental impacts to the composition and function of
the natural ecosystem through changes in competition, predation, or habitat modification. The
Project provides opportunities for IMS to establish in two ways: on structures installed as part of the
new facility infrastructure, and on project vessels working in the harbour during the 38 week dredging
period and those utilising the berths during operation. The former will offer the highest chance of
colonisation when first immersed, with likelihood decreasing with time as exposed surfaces are
colonised by established native marine flora and fauna communities. The risk of project vessels being
colonised may increase during the project as antifouling systems age and become damaged during
operation.
Of the seven pest species designated as the basis for management of domestic ballast water
movements, none is currently listed as present in Port Hedland, which means that water taken up as
ballast or entrained in Port Hedland is deemed low risk for discharge in other Australian ports and
coastal waters. The proposed dredge vessel that will be used during dredging has been operating in
Port Hedland for dredging associated with RGP6 project and FMG third berth project. Quarantine
measures will have already been undertaken prior to commencement of dredging.
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5.5.2 Management of Introduced Marine Species
Management Area Introduced Marine Species
Performance Objective Minimise the risk of introduction of unwanted marine organisms consistent with the Australian Quarantine Inspection Services (AQIS) guidelines for ballast water management and ANZECC code of practice for anti-fouling and in-water hull cleaning and maintenance.
Management Actions Prior to mobilisation and during dredging:
• Comply with AQIS (Australian Quarantine Inspection Service) requirements, State and Federal legislation and particular provisions presented in the ARI document for dredges.
• Any vessels coming to Port Hedland for the project from other Australian location that carry ballast or entrained water are required to have the risk status of that water assessed, considering the location of uptake and time of year, and to manage the water in accordance with the requirements of the National System for the Prevention and Management of Marine Pest Incursions, if it is deemed to be high risk.
• Any vessels coming to Port Hedland for the project from overseas or domestically should be subject to a biofouling risk assessment following guidance within the National Biofouling Management Guidance for Non-Trading Vessels document. Vessels assessed as posing a risk should be inspected to ensure they are free of biofouling and preferably dry-docked for cleaning and repair/renewal of the antifouling system immediately prior to departure for Australia.
• All areas where mud and sediments can collect, including anchor and chain lockers and hoppers, should be inspected and cleaned prior to a vessel’s departure for Port Hedland. Anchor chains, cables, and other gear that has been deployed overboard should also be inspected and cleaned of any attached or entangled marine growth. These procedures should be repeated prior to departure from Port Hedland to prevent translocation of species away from this region.
Monitoring Monitoring and surveillance of the dredge vessel and barges in accordance with AQIS and PHPA quarantine requirements.
Responsibility The Dredging Contractor is responsible for complying with existing PHPA quarantine requirements and management.
Reporting Following completion of each vessel inspection a report will be developed and submitted to PHPA Project Manager.
Corrective Action Implementation of contingency measures as required by PHPA quarantine requirements.
Notification to DSEWPaC and the DEC in the event of introduction of a marine pest species.
Relevant References/ Standards
Australian Quarantine Act 1908
Australian Ballast Water Management Requirements (AQIS, 2008)
National Biofouling Management Guidance for commercial Vessels (CA 2009a)
National Biofouling Management Guidance for Non-trading Vessels (CA 2009b)
ANZECC Code of Practice for Antifouling and In-water Hull Cleaning and Maintenance (ANZECC, 2000)
Environmental Protection Act 1986 (WA).
Fisheries Resources Management Act 1994 (WA).
PHPA Marine Pest procedures.
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5.6 Hydrocarbon Management
5.6.1 Overview
Hydrocarbons used during the dredging will include diesel and smaller amounts of lubricating oil and
grease for dredging equipment. Diesel is a ‘light oil’ and small spills of 2000-20000 L will usually
evaporate and disperse within a day or less; for larger spills, a residue of up to one-third of the
amount spilled will usually remain after a few days.
Direct contact with diesel can affect marine birds by ingestion during preening and hypothermia from
matted feathers, although the oil evaporates so rapidly that the number of birds affected is usually
small (NOAA 2006). Small spills have the potential for serious impact if they occur close to a large
nesting colony or are transported into an area of large bird population (NOAA 2006).
Given that there unlikely be large seabird colonises only localised impacts are predicted should diesel
be spilt. Therefore it is likely that only invertebrates and fish may be exposed and subsequently
affected by such incidents although area of spill extent is thought to be minimal given the small
volumes of fuel that will be used during dredging activities.
Land based activities including construction and management of the DMMAs could result in a minor
hydrocarbon spillage from plant and equipment. However, the Project is unlikely to require
significant volumes of hydrocarbons to be either stored onsite.
5.6.2 Management of Hydrocarbon Spills
Management Area Hydrocarbon Spills
Performance Objective To ensure hydrocarbons are handled and stored in a manner that minimises the potential impact on the environment through leaks, spills and emergency situations.
Hydrocarbon spills will be managed in accordance with the requirements of PHPA’s Marine Oil Pollution Management Plan.
Dredge vessels: tanks and machinery shall be equipped with measurement and overflow protection (i.e. flow and level meters, relief valves, overflow protection valves and emergency shut-off).
Land based plant and equipment shall be appropriately maintained and serviced in accordance with industry standards.
Industry standards, port authority and pollution prevention regulations shall be adhered to during:
• Refuelling;
• Transfer;
• Storage; and
• Handling of hazardous materials (e.g. bunding, level gauges, overflow protection, drainage systems and hardstands).
Management Strategy
Volumes of stored fuels and chemicals will be limited to day-use. Use of appropriately licensed mini-tankers for refuelling.
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Management Area Hydrocarbon Spills
Hydrocarbons (including hydrocarbon wastes) shall be stored in appropriately labelled drums or tanks and in bunded areas that can contain 110% of material stored within.
Equipment will be designed and operated to prevent spills and leaks through the provision of in-built safeguards such as relief valves, overflow protection, and automatic and manual shut-down systems.
Establish comprehensive vessel refuelling procedures to avoid or reduce the possibility of a release include as a minimum the requirements for:
• adhering to all port authority and pollution regulations;
• refuelling during daylight hours where possible, depending on sea conditions;
• refuelling within established safety boundaries and during weather/sea/visibility conditions that will minimise potential release risk;
• training personnel involved with refuelling or fuel transfer in their roles, functions and responsibility, including emergency response;
• maintaining open communication channels;
• deploying spill prevention systems in accordance with established procedures and regulatory requirements; and
• maintaining emergency response equipment to ensure that it is readily available.
All spills to land >10 L will be communicated to the Environmental Superintendent. An incident report will be completed by the Shorebased Contractor and submitted to PHPA’s Project Manager.
All personnel will be familiar with the use of oil spill clean up kits and dispose of waste in the prescribed manner.
Controlled wastes shall be managed as per the Environmental Protection (Controlled Waste) Regulations 2004 (WA).
Monitoring The Dredge Contractor shall undertake regular maintenance and systematic inspection of vessels, plant and equipment shall be conducted with particular attention to hydrocarbon storage areas and bunding to reduce likelihood of equipment failure, spills and leaks.
The Dredge Contractor shall keep maintenance and inspection logs/records for all vessels, major plant and equipment and. Records may be requested by PHPA at any time.
Monthly reporting of all incidents. Review of trends verse site activity.
Responsibility Both the Dredge and Shorebased Contractors are responsible for complying will the relevant management strategies during construction in accordance with their contractual responsibilities.
Reporting Both the Dredge and Shorebased Contractors must immediately notify PHPA of an environmental incident. Further, either Contractor must complete an environmental incident report, which shall include appropriate information on corrective and preventative actions taken, and submit this to PHPA as soon as practicable, but within 24 hours of the incident occurring.
Records of hazardous materials received, stored and dispensed shall be maintained and reconciled. Where any discrepancy in records indicates that leakage may be occurring, the suspected facility/storage area shall be subject to investigation.
Corrective Action Implementation of contingency measures as required by PHPA’s Marine Oil Pollution Management Plan (Appendix 2).
Relevant References/ Standards
PHPA’s Marine Oil Pollution Management Plan (Appendix 2).
Environmental Protection (Controlled Waste) Regulations 2004 (WA).
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5.7 Waste Management
5.7.1 Overview
Solid and liquid wastes generated during dredging activities and construction of the DMMAs have the
potential to negatively impact on the surrounding environment if appropriate waste management
measures are not implemented. Solid and liquid wastes that may be generated by the Project include:
• Packaging material (plastic wrapping, pallets, etc);
• Concrete;
• Scrap metal;
• Waste oil, hydrocarbons and hazardous materials (see Section 5.6);
• Recyclable materials (paper, cardboard, aluminium);
• General food packaging and scraps; and
• Domestic sewage.
Although no discharge of waste to the marine environment within the 12 nm limit is to take place, the
potential exists for accidental discharges of small quantities of solid or liquid wastes to the marine
environment. Accidental waste discharges arising from dredge vessels and land based activities (not
including hydrocarbons) could include:
• Deck drainage, which may comprise primarily rain water and washdown water, but may
include small amounts of waste material;
• Potentially contaminated drainage, including drainage from machinery spaces and bilges; and
• Engine cooling water.
• The accidental discharge of waste material (without appropriate dilution or treatment) to the
marine environment may:
• Contaminate food sources;
• Result in additional nutrients and pathogens in the water column (potentially leading to algal
blooms or toxicity);
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• Cause death or injury of marine fauna if ingested or entangled; and
• Solid wastes that may be generated during construction include plastics, materials packaging,
scrap metal, containers, wood, and food waste.
5.7.2 Management of Wastes
Management Area Waste Management
Performance Objective To ensure best practice management for the handling and storage of all waste and hazardous materials related to the dredging
Compliance with Regulations and Standards:
• Controlled wastes shall be managed as per the Environmental Protection (Controlled Waste) Regulations 2004 (WA).
• Chemicals carried in packaged, solid or bulk form will comply with the regulations of Part A of SOLAS Chapter VII and the IMDG Code regarding the classification, packing, marking, labelling and placarding, documentation, stowage, handling and emergency response action of dangerous goods.
• All waste designated as hazardous/dangerous requiring disposal shall be packaged, stored and transported in accordance with IMDG (International Maritime Dangerous Goods) requirements. Vessel documentation shall include Material Safety Data Sheets (MSDS’) for each substance carried.
• All vessels will comply with the compulsory insurance and insurance certificate requirements of the International Convention on Liability and Compensation for Damage in Connection with the Carriage of Hazardous and Noxious Substances (HNS) by Sea 1996.
• Vessels of 24 m or more in length but less than 400 gross tonnage engaged in international voyages will carry a Declaration on Antifouling Systems (prohibiting the use of harmful organotins in antifouling paints) in compliance with the International Convention on the Control of Harmful Antifouling Systems on Ships.
• All sewage and grey water treatment systems shall be frequently checked, maintained and monitored to ensure systems are efficient, fully operational and discharging treated water in accordance with MARPOL 73/78 Convention Annex IV (sewage) and Annex V (garbage).
• No residues containing noxious substances will be discharged within 12 nm of the nearest land, in compliance with MARPOL 73/78 Convention Annex II.
Management Actions
Handling and Storage of Wastes:
• Waste management requirements shall be communicated to personnel (i.e. through inductions, pre-starts and/or Job Hazard Analyses (JHAs)).
• Communition systems on vessels shall be capable of handling the volumes generated and maintained regularly so they efficient and fully operational at all times.
• Solid and liquid wastes and hazardous materials shall be stored in appropriately labelled drums or tanks.
• Hazardous substances handling is to be carried out by suitably trained personnel only.
• Hazardous material storage areas shall be engineered and designed to handle the volumes and operating conditions (both normal and upset conditions) specifically required for each substance, including product identification, transportation, storage, control and loss prevention (e.g. bunding and drainage).
• Incompatible products will not be stored together.
• Empty liquid waste containers shall be segregated from other wastes and
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Management Area Waste Management
stored in designated areas.
Monitoring PHPA is responsible for the review of monthly reports of incidents.
Responsibility Both the Dredge and Shorebased Contractors are responsible for complying will the relevant management strategies during construction in accordance with their contractual responsibilities.
Reporting Both the Dredge and Shorebased Contractors shall report any incidents of waste entering the marine environment to PHPA as soon a possible (but within 48 hours) and implement appropriate clean up procedures.
Corrective Action Implementation of contingency measures as required by PHPA’s waste management guidelines and PHPA’s Marine Oil Pollution Management Plan (Appendix 2).
Relevant References/ Standards
PHPA’s existing waste management guidelines.
Environmental Protection (Controlled Waste) Regulations 2004 (WA).
International Convention on the Control of Harmful Antifouling Systems on Ships.
IMDG (International Maritime Dangerous Goods) requirements.
MARPOL 73/78 Annex II.
MARPOL 73/78 Convention Annex IV (sewage) and Annex V (garbage).
International Convention on Liability and Compensation for Damage in Connection with the Carriage of Hazardous and Noxious Substances (HNS) by Sea 1996.
5.8 Offshore Spoil Ground Management
5.8.1 Overview
Spoil Ground I is located approximately 11 km offshore in water depths ranging from -8 to -13 m CD.
Disposal activities have been predicted to generate sediment plumes through mobilisation of
sediments during disposal of dredged material. Modelling outputs predict that sediments plumes
have been predicted to migrate outside the proposed spoil ground boundary. Potential water quality
impacts associated with the disposal activities are addressed in Section 5.1, whilst those associated
with potential impacts to BPPH are addressed in Sections 5.2 and 5.3 and those associated with
potential impacts to marine fauna are addressed in Section 5.4.
A Sea Dumping Permit application was submitted to DSEWPaC on 20 August 2010, who is currently
reviewing the application with a decision expected on 26 November 2010.
5.8.2 Management of Spoil Ground
Management Area Offshore Spoil Ground Management
Performance Objective To carry out the disposal of dredged material to the offshore disposal ground, Spoil Ground I, in a manner that is consistent with the requirements of the Sea Dumping Permit (SDP).
Management Actions Although the SDP is still being assessed by DSEWPaC and therefore the requirements of the permit are not yet known, it is likely that the permit may include the following management measures that will be implemented:
• It will be established by GPS that, immediately prior to dumping, the vessel is within the approved Spoil Ground I boundary.
• Each load of dredged material will be dumped so that dumped material is
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Management Area Offshore Spoil Ground Management
distributed evenly over the area within the disposal ground.
• Any dredge or barge used in connection with disposal activities and any associated towing vessels must comply with the relevant state, national and/or international standards with respect to seaworthiness, safety and environmental requirements, or any rules or conditions laid down by the certifying classification society, and be capable of disposing the dredge material at the disposal ground.
• The volume of dredged material (in cubic metres) dumped at Spoil Ground I will be estimated and compared daily to the disposal quantities.
• Regular progress surveys will be recorded and compared to the approved disposal quantities.
• Maintaining calibration of the hydrographic survey systems onboard the dredge.
• Monitoring of weather and sea conditions.
• Implementation of the Tiered Monitoring Framework following a water quality trigger breach in accordance with the monitoring program (Figure 6-1).
Responsibility The Dredge Contractor is responsible for complying will all management strategies during construction.
PHPA is responsible for reporting as detailed in Section 7.
Monitoring A bathymetric survey of Spoil Ground I will be undertaken within one month and again within 12 months of the completion of all disposal activities.
Dredge Contractor to monitor the operation on a continual basis and report any incidents that are likely to cause substantial changes to water quality.
Implementation of the Routine Water Quality Monitoring Program and Reactive Coral Health Investigation (Section 6.2 and Section 6.3, respectively).
Reporting Weekly plotting sheets including the following information to be retained for audit purposes:
• the times and dates of when each dumping run is commenced and finished;
• the position (as determined by GPS) of the vessel at the beginning and end of each dumping run, with the inclusion of the path of each disposal run; and
• a means of estimating the volume of dredged material (in cubic metres) dumped and quantity in dry tonnes at the disposal site for the specified disposal period.
• A report on the bathymetric survey will be provided to the DSEWPaC within two months of the final bathymetric survey being undertaken. This report will include a chart showing the change in sea floor bathymetry as a result of dumping and include written commentary on the volume of dumped material that appears to have been retained within each the disposal ground.
Corrective Action Implementation of the reactive monitoring following a water quality trigger breach in accordance with the monitoring program (see Section 6).
Notification to DSEWPaC and the DEC, if water quality exceeds the predicted trigger values, for consideration of need for any corrective action.
Relevant References/ Standards
Sea Dumping Permit – application is currently being assessed by DSEWPaC.
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5.9 Onshore Dredge Material Management
5.9.1 Overview
Five onshore DMMAs have been identified for the South West Creek Development, all located within
the PHPA UDP Development Areas A, B and G (PHPA 2009). Two are existing DMMAs, one currently
holds approval under Part IV, and approvals are sought for the remaining two in the ERD. The
DMMAs are shown in Figure 1-3 and described below:
• DMMA A and B are located to the south of Anderson Point. Both DMMAs are existing dredge
material management areas and were used as a disposal ground for dredged material arising
from FMG’s third berth at Anderson Point;
• DMMA B-south is located to the south of DMMA B, and approvals under Section IV have
already been obtained by FMG (WA EPA Ministerial Conditions 771);
• Proposed DMMA G is located to the south of South West Creek and east of the BHPBIO rail
line; and
• Proposed DMMA B-north situated north of the existing DMMA B.
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5.9.2 Management of the DMMAs
Management Area Offshore Spoil Ground Management
Performance Objective To minimise the generation and migration of turbid plumes and the generation of ASS as a result of the tailwater discharge from the DMMAs during onshore disposal activities and thereby causing no impacts to coral and mangrove communities.
Management Actions Water Quality:
• Implementation of the Tiered Monitoring Framework following a water quality trigger breach in accordance with the monitoring program (Figure 6-1).
• Management measures to control the tailwater discharge associated with reclamation are presented in Section 5.1.2.
• Surface water run-off from the DMMA’s will be contained where appropriate and discharge controlled such that there are no significant, physical off-site impacts;
Terrestrial Flora and Fauna:
• The disturbed footprint shall be minimise through the clear demarcation of vegetated areas marked for clearing.
• Accidental hydrocarbon spills shall be managed in accordance with the measures described in Section 5.6.2.
• Waste management measures shall be implemented (see Section 5.7.2) to reduce the risk of liquid wastes affecting vegetation health or being ingested by fauna.
• Speed restrictions, driver awareness and removal of road kill shall be enforced to minimise potential impacts arising from vehicular movement.
• All equipment and vehicles shall be washed down prior to arrival to Project site areas in order to minimise the spread of weeds.
• Weed-free fill material shall be used; and
• Noise emissions and use of lighting during construction shall be minimised where practicable.
Acid Sulfate Soils:
• Material proposed for use for the construction of the earth bunds surrounding the DMMAs will not be sourced unless a detailed soil assessment is conducted and the proposed material does not contain PASS.
• Non-ASS will be pumped to the DMMAs.
• Monitoring of the DMMA discharge to ensure it meets the action criteria outlined in Dewatering Effluent and Groundwater Monitoring Guidance For Acid Sulphate Soil Areas (DEC 2006b). Total Titratable Acidity (TTA), Electrical Conductivity (EC) and pH will be monitored weekly to ensure that water quality parameters are maintained at a pH > 6 and a TTA < 40 mg/L (see Section 6.6.1.2).
Dust:
• Regular watering of unsealed roads, exposed surfaces, active construction areas and stockpiles.
• Restriction of vehicle movements and vehicle speeds to reduce dust emissions.
• Use of environmentally safe dust suppressants.
• General housekeeping practices to ensure that there is no accumulation of waste materials within the construction site that may generate dust.
• Staff induction program to ensure all employees are made aware of the need to minimise dust generation.
• Reporting of any community complaints regarding dust levels.
Visual Amenity:
• The height of the DMMAs will not exceed +12 m AHD.
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Management Area Offshore Spoil Ground Management
• Vegetation screening and landscaping to reduce visibility of the DMMAs will be considered.
• Dredge material management to keep the footprint and height of dredged material to a minimum.
• The DMMA G bund walls directly adjacent to Finucane Road will be partially vegetated using vegetation suitable to the characteristics of the area.
Construction Noise:
A noise management plan will be developed in order to undertake construction activities, in accordance with the Environmental Protection (Noise) Regulations 1997.
Measures that may be taken to reduce noise emissions during dredging and construction include:
• Educating and training employees and contractors with respect to noise management.
• Ensuring noise emissions are considered when sourcing plant and equipment.
• Ensure that all plant is maintained in operating order in accordance with industry best practice.
• Ensure that all equipment meets equipment noise specifications and put in place action plan if requirements are not met.
• Switch off all equipment when not in use.
• Scheduled maintenance and monitoring of equipment with a view to minimising noise emissions.
• Restricting high levels of noise emissions to appropriate daylight hours.
Additional measurements are applicable for construction activities at night time. Measurements to be included in the noise management plan should include:
• Consideration of acoustic enclosure of noise sources, i.e. CSD cutter drivers and engines.
• Need for work to be done out of hours.
• Types of activities which could be noisy.
• Predictions of noise levels.
• Control measures for noise and vibration.
• Procedures to be adopted for monitoring noise emissions.
• Complaint response procedures to be adopted.
Responsibility Both the Dredge and Shorebased Contractors are responsible for complying will the relevant management strategies during construction in accordance with their contractual responsibilities.
PHPA is responsible for reporting as detailed in Section 7.
Monitoring Dredge Contractor to monitor the operation on a continual basis and report any incidents that are likely to cause substantial changes to water quality.
Implementation of the Routine Water Quality Monitoring Program (Section 6.2), Reactive Coral Health Investigation (Section 6.3), the Routine Surface Sediment Profiling Program (Section 6.4) and other monitoring required for the DMMAs described in Section 6.6.
Reporting PHPA is responsible for reporting as detailed in Section 7.
Exceedences of DEC criteria will be reported.
Relevant References/ Standards
Pilbara Coastal Water Quality Objectives.
ANZECC/ARMCANZ (2000) Water Quality Objectives.
Dewatering Effluent and Groundwater Monitoring Guidance For Acid Sulphate Soil Areas (DEC 2006b).
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6. MONITORING PROGRAMS AND INSPECTIONS
Environmental attributes most susceptible to dredging and reclamation activities associated with the
proposal include:
• Water Quality.
• Coral Health;
• Mangrove Health.
In addition to the management actions that will be implemented during dredging and reclamation,
environmental monitoring of the marine environment will also be undertaken to verify the predicted
impacts and to ensure that impacts do not exceed their predicted magnitude.
The following monitoring is proposed for the Project:
• Physical water quality monitoring using telemetry based water quality loggers.
• PASS monitoring of sediment leaving the discharge pipe into the reclamation area.
• Monitoring of sedimentation.
• Coral/mangrove health, abundance and diversity. The aim of monitoring will be to identify
any change in abundance, diversity and health of corals at several key locations for the
duration of dredging, disposal and reclamation activities.
Data collected in the field will be reported to the DEC providing a series of conclusions and
recommendations for management and monitoring to ensure any impacts are rapidly identified and
mitigated.
6.1 Tiered Monitoring Framework
The Tiered Monitoring Framework (TMF) has been developed in conjunction with management
performance indicators, management triggers, and monitoring programs described in Section 6.2, 6.3,
6.4, 6.5 and 6.6. The main objective of the TMF is to ensure that a set of compulsory and optional
management actions are in place during dredging and reclamation that can be implemented should
environmental monitoring detect a change in water quality, mangrove health and/ or coral health
which are greater than the changes seen ‘naturally’ across reference sites; that is, quantifiable
changes which can be attributed to dredging activities, (i.e. compared to reference sites), or where
development activities are considered to be of a higher environmental risk, warranting more
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conservative management. A diagram of the proposed TMF for water quality/coral health and
sedimentation/mangrove health management and monitoring has been provided in Figure 6-1 and
Figure 6-2, respectively, for the predicted area of impact. As part of the TMF, a set of water quality
and sedimentation monitoring triggers have been developed (Section 6.2.1 and Error! Reference
source not found., respectively) to provide a proactive management strategy for the protection of
coral and mangrove communities during the monitoring program. These water quality/sedimentation
triggers will be continually reviewed during dredging to ensure that they remain relevant and
applicable to the health of corals and mangroves within the predicted impact areas.
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1Yes
Routine Water Quality and Reactive Coral monitoring Tiered Management Framework
Water Quality Monitoring Program
Frequency – Continuous logging
Duration – Starting 14 days before the commencement of dredging and disposal
and extending one month after cessation of disposal
Location – Impact and reference sites
Method – Turbidity (NTU)2.
Reporting – Report results online via telemetry continuously after commencement
of monitoring
Initiate BPP
survey at
sensitive receptors
Water quality exceeds
trigger of 80th percentile of baseline data and there is
significant difference to reference site data
Net BPP
mortality >10%
Signs of
coral
stress
Continue disposal
Continue monitoring and
reporting
Inform Dredging
Contractor
Level 1 Management
Implement 1 or more of the following:
1. Target larger PSD at dredge footprint
2. Report results to relevant regulatory authorities
3. Continue monitoring
Cease dredging
1. Immediately report findings to relevant regulatory
authorities
2. Continue monitoring
Water quality exceeds trigger of 95th percentile of
baseline data and there is significant difference to
reference site data
Water quality exceeds trigger of 99th percentile of baseline data and there is
significant difference to reference site data
Level 3 Management
Implement 1 or more of the following:
1. Reduce disposal shifts;
2. Report results to relevant regulatory authorities
3. Continue monitoring
No
No
No Yes
Yes
NoYes
Yes
1Yes
1Yes
Note 2: NTU will be
converted to TSS via
established relationship, and
samples taken throughout
programme to validate
Note 1: Confirmation of “trigger”
Step 1: Monitoring – a trigger value is exceeded by a value of 2 NTU or greater over a period of one neap and one spring tidal cycle and the instrument is reliableIf NO – continue monitoring and rectify instrument
issueIf YES – go to Step 2
Step 2: Proximity and Influence – Disposal operation has been operational within the last 10 daysIf NO – Report to relevant regulators
If YES – Go to Step 3Step 3: Natural exposure and variation – is the
exceedence caused by naturally high levels of turbidity (i.e. due to strong wave resuspension or cyclone activity)
If NO – Report to relevant regulators If YES – Go to Step 4
Step 4: Turbidity is generated from disposal activities If NO – Investigate cause and report to DEWHA. If YES – Implement investigation and reporting to
Regulators
Level 2 Management
Implement 1 or more of the following:
1. Reduce disposal;
2. Target larger PSD at dredge footprint
3. Report results to relevant regulatory authorities
4. Continue monitoring
No
No
� Figure 6-1: Routine Water Quality and Reactive Coral Monitoring Tiered Management Framework
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Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
Routine Surface Sedimentation Profiling and Reactive Mangrove Health Tiered Management Framework
Continue dredging/reclamation
Continue monitoring and reporting
Sedimentation Monitoring Program
Frequency – Continuous logging;Duration – Starting 14 days before the commencement of dredging and extending two months
after cessation of dredging
Location – Impact and reference sites
Method – Sediment profiling
Reporting – Report results monthly to relevant regulatory authorities after the commencement of
dredging
Sedimentation at
impact sites
statistically exceeds
reference site data
Significant differences observed between impact and
reference sites
Level 1 ManagementImplement 1 or more of the following:
1. Reduce dredging in affected areas;
2. Report results to relevant regulatory authorities
3. Continue monitoring
Level 2 Management
Implement 1 or more of the following:
1. Reduce dredging in affected areas and/or reduce dredging
shifts to match tide/wind conditions.
2. Report results to relevant regulatory authorities
3. Continue monitoring
Level 3 Management
Implement 1 or more of the following:
1. Reduce dredging shifts;
2. Report results to relevant regulatory authorities
3. Continue monitoring
Implement Mangrove Health Monitoring
Continue Mangrove Health Monitoring
Continue Mangrove Health Monitoring
Significant differences observed between impact and
reference sites
Significant differences observed between impact and
reference sites
Continue Mangrove Health Monitoring
Significant differences observed between impact and
reference sites
No
Cease dredging
1. Immediately report findings to relevant regulatory authorities
2. Continue monitoring
Yes
Yes
Yes
No
No
Yes
No
No
No
� Figure 6-2: Routine Surface Sedimentation Profiling and Reactive Mangrove Health Tiered Management Framework
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6.2 Routine Marine Water Quality Monitoring Program
The Pilbara coastal water quality objectives state that water quality within the dredge is to be
maintained at a level that provides 90% ecological protection within the inner harbour. Some
DMMA’s outfalls will discharge in 99% ecological protection areas. The EPBC Act requires protection
to all commonwealth marine waters which are applicable to the offshore Spoil Ground I. The
following methods and procedures define the monitoring that will be implemented during dredging
and reclamation to ensure changes to water quality will be within predicted impacts identified in
Section 4.1. Water quality monitoring proposed will act as a proxy for the determination of identifying
impacts to coral community and other BPP health predicted during dredging, reclamation and
disposal.
6.2.1 Development of Trigger levels
The objective in setting triggers is to set be able to monitor TSS concentrations that can act as a signal
or proxy for determination of ecological impacts within a defined impact zone. The exceedance of
that initial level would then trigger a series of predetermined management responses. The underlying
basis for the threshold is that a tangible risk of impact is evident once the threshold has been
exceeded (Based on McArthur et al. 2002).
Trigger levels proposed for the inner harbour dredging have been based on baseline water quality
data collected within South West Creek over a period six months. Trigger levels proposed for the
tailwater discharge from the five DMMAs have been based on baseline water quality data collected
within South West Creek as well as prior to commencement of the discharge. Monitoring locations
are located in areas which require a high/medium level of ecological protection based on the Pilbara
Water Quality ecological objectives have been adopted and therefore the 80th percentile of baseline
data will be used.
Trigger levels for the offshore disposal ground will be established based on collection of baseline data
prior to commencement of disposal activities. At Spoil Ground I, PHPA have committed to manage
impacts so that no observable effect is measurable at the edge of the closest sensitive receptors (i.e.
coral sites). As such, a rolling median over a spring and neap tidal period of the 80th percentile of
baseline and reference data will be used to trigger a management response (Section 6.1).
6.2.2 Monitoring Sites
Two water quality impact sites have been established within the predicted area to be influenced by
dredging activities (within Port Hedland inner harbour) (Figure 6-3). Two reference sites will also be
established. Three sites (two ‘impact’ and one ‘reference’) will be established for monitoring water
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quality associated with offshore disposal activities (Figure 6-4). The DMMAs will be monitored for
water quality when in use Table 6-2.
Discharge from the DMMAs will be monitored for pH, DO, turbidity (NTU), temperature and salinity at
the point the tailwater enters the receiving environment.
Table 6-1 and Table 6-2 provide the geographic coordinates for each site, data to be collected at each
site and the site’s function at the offshore disposal ground, DMMAs and adjacent to the dredge
footprint.
� Table 6-1: Proposed Water Quality Monitoring Sites for Offshore Disposal
Position (MGA Zone 50) Details Site Name
Easting Northing Water Quality Equipment
Water Quality Monitoring Sites
Spoil Ground Reef 663682 7768725 Telemetry + Logging
Minilya Bank 670983 7771075 Telemetry + Logging
Reference Site
Little Turtle Reef 688256 7785329 Telemetry + Logging
� Table 6-2: Proposed Water Quality Monitoring Sites for Dredging and at the DMMAs
Position (MGA Zone 50) Details Site Name
Easting Northing Water Quality Equipment
Water Quality Monitoring Sites
SWC1 662430 7750687 Telemetry + Logging
SEC1 666086 7749980 Telemetry + Logging
DMMAs To be determined To be determined Telemetry + Logging
DMMA Discharge Point
DMMA discharge point n/a n/a Discharge monitoring site – twice daily using hand-held unit
Reference Sites
Reference site 1 To be determined To be determined Telemetry + Logging
Reference site 2 To be determined To be determined Telemetry + Logging
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Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
� Figure 6-3: Location of proposed water quality monitoring sites associated with dredging activities
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Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
� Figure 6-4: Location of proposed water quality monitoring sites associated with disposal activities
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Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
6.2.3 Methods
Turbidity will be measured using an in situ water quality logger with telemetry capability (Figure 6-5).
Each logger will be deployed from a survey vessel and positioned approximately 1 m above the
seabed on a steel frame at each specified monitoring location using divers. Each logger unit will be set
up to measure turbidity every 30 minutes.
Data will be downloaded daily using the telemetry system deployed with the logger by the PHPA
environment manager. Loggers will be calibrated monthly to ensure accurate data sets are acquired.
� Figure 6-5: Telemetry based loggers and associated probes
6.2.3.1 Correlation of TSS and NTU
Correlation of TSS and turbidity is undertaken to validate whether predicted zones of impact from
modelling are a true representation of the plume extent during dredging activities. Water samples will
be collected with a one litre Van Dorn bottle and measured for NTU and TSS during a single event
during the dredging program. Two sites will be selected in the immediate vicinity of the dredge.
Replicated samples will be collected from the surface, mid and bottom of the water column at each
site and analysed for:
• TSS (samples sent to the laboratory);
Turbidity, pH, DO, salinity, temperature, data loggers and power packs
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• NTU (both measured on site and as samples sent to the laboratory); and
• Particle Size Distribution (samples sent to the laboratory).
Samples will be sent to NATA accredited laboratories for quantitative analysis. Results may also be
used to make comparisons between measured turbidity values and those predicted in the numerical
model (i.e. indication of modelling accuracy).
6.2.3.2 Sediment Flux Measurements
Sediment flux measurements will be carried out adjacent to the dredging and disposal activities in
order to collect data to be used to verify the extent of the modelled plume predictions. The
monitoring will be undertaken as described below:
• An Acoustic Doppler Current Profiler (ADCP) in bottom track mode will measure the current
profile over pre-defined transects that captures the spill leaving the dredge footprint and
disposal ground. The location of the transects will vary depending on the location of the
dredging/disposal operations and the prevailing currents.
• Processing of the ADCP backscatter data utilising a recognised sediment flux analysis package
to provide data on the concentration profiles and sediment flux through the executed
transects.
• The transects shall be placed as close to the dredging works as possible depending on safety
limits established in consultation with the Dredge Contractor.
• The length of each transect will be chosen to ensure that the entire plume is captured, with
the typical length of each transect will be in the order of 200 to 500 m.
• Sediment flux measurements will only be undertaken during daylight hours.
The sediments escaping the dredging area shall be measured on a daily basis (for at least 28 days) via
the sediment flux transects. This period of sediment flux measurements should be timed to cover the
entire dredging works with the level of effort distributed evenly. The sediment flux is defined as the
product of the current and suspended sediment profile determined from the ADCP backscatter data.
The transects will be located such that the entire plume is captured including areas immediately
adjacent to the plume exhibiting the prevailing background concentration. On each day of operation a
maximum of six transects shall be undertaken within each dredge area. For those days with less
activity, a lower number of transects may be undertaken.
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The measured sediment flux shall be converted into an estimate of the sediment release rates for the
specific operation (i.e. dredging or disposal) monitored.
In order to reliably simulate and validate the transport and fate of the fine material released from
dredging and disposal activities Owen tube tests will be carried out once per week for four weeks,
where the Dredge Contractor shall provide one large volume (more than 5 kg) of sediment for
extraction of fines content for fall velocity testing in the laboratory.
Vertical profiling of the water column will also be carried out using a water quality sonde in the
vicinity of the dredge during both dredging and disposal activities on a weekly basis.
6.2.4 Frequency
6.2.4.1 Phase I – Pre Dredging
Baseline water quality was data collected between December 2009 and May 2010. The baseline water
quality program comprised the deployment of water quality loggers to collect time series water
quality data for turbidity. This will be restarted a minimum of two weeks before dredging starts
6.2.4.2 Phase II – During Dredging
Data from the telemetered loggers will be evaluated daily during dredging management response
actions including coral health monitoring will be implemented should trigger levels be exceeded.
6.2.4.3 Phase III – Post Dredging
Downloading of water quality monitoring data from the loggers will continue until water quality levels
return to pre dredging levels after the cessation of dredging, or one month following dredging.
6.2.5 Data Analysis and Reporting
Water quality data collected daily during the dredge monitoring program will be used to provide early
warning of potential water quality deterioration at the monitoring sites. The likelihood of a link
between dredging and water quality decline will be assessed in terms of the following factors:
• Location of and status of dredging activities in relation to the site(s) at the time of the
exceedence;
• Hydrodynamic conditions, e.g. wind, tide, wave and swell state at the time of the exceedence;
• Dewatering statistics prior to exceedance (flow, turbidity etc.);
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• Effects of extreme weather events in the region; and
• Spatial extent of water quality decline.
The seven day running median at these telemetered sites will be calculated for individual sites from
data points recorded every 30 minutes. The statistics will be calculated daily and compared to the 80th
percentile of data collected via telemetry from the two specified reference sites.
6.3 Coral Health Investigation Program
The Reactive Coral Health Investigation Program will be undertaken should water quality trigger levels
be exceeded during dredging and disposal activities at reference sites.
6.3.1 Monitoring Sites
Coral health monitoring sites will be established at the water quality monitoring sites discussed in
Section 6.2 (Table 6-3 and Table 6-4). Monitoring sites within the inner harbour and adjacent to Spoil
Ground I have been established based on coral communities identified in these areas. Additional
reference sites that require establishment should be located in an area that display similar coral
composition, bathymetry and water quality conditions to impact locations.
� Table 6-3: Proposed Coral Monitoring Sites for Offshore Disposal
Site Name Position (MGA Zone 50)
Easting Northing
Coral Monitoring Sites
Spoil Ground Reef 663682 7768725
Minilya Bank 670983 7771075
Reference Site
Little Turtle Reef 688256 7785329
� Table 6-4: Proposed Coral Monitoring Sites for Dredging
Site Name Position (MGA Zone 50)
Easting Northing
Coral Quality Monitoring Sites
SWC1 662430 7750687
SEC1 666086 7749980
FIC (offshore but applicable for dredging not disposal) 664274 7755496
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Reference Sites
Reference site 1 To be determined To be determined
Reference site 2 To be determined To be determined
6.3.2 Methods
Pre and Post dredging surveys will be undertaken to quantify the composition and mean percent
coverage of BPPH in both the inner harbour and the outer harbour sites. PHPA recommends the line
intercept method (belt 2m wide) as a rapid method for identification of BPP health. Even if corals are
sparsely spread, this method captures every coral and has a higher level of statistical rigor than other
methods (i.e. Stoddart, Blakeway et al. 2005). Divers produce data instead of photos, and results are
available within hours instead of days, as typically is the case with other camera based techniques.
The composition and mean percent cover of the different BPPH components (e.g. corals, macroalgae
etc.) will be quantified, similarly sedimentation and mucous production of corals will be quantified as
a proxy for health. The same methodology will be undertaken for the post dredge survey and any
reactive water quality monitoring. The composition and mean percent cover of the different BPP
components will again be determined and then compared to the pre-dredge survey data.
6.3.3 Frequency
6.3.3.1 Phase I – Pre Dredging
A baseline coral health survey will be undertaken to identify the existing condition of coral
communities located at sites SWC1 and SEC1 and to identify and establish coral monitoring reference
sites located in adjacent creek systems that will not be impacted by the Project.
6.3.3.2 Phase II – During Dredging
Coral health will be monitored at identified impact and reference sites following exceedance of
adopted water quality trigger levels.
6.3.3.3 Phase III – Post Dredging
A post dredging coral health investigation will be undertaken to define any impact between pre and
post dredging/disposal activities
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6.3.4 Data Analysis and Reporting
Data will be collated within one week of completion of each coral health investigation. Data between
each site will be statistically compared using statistical analysis to determine impacts if any have been
observed as a result of dredging activities.
6.4 Routine Surface Sediment Profiling Monitoring Program
The primary effects of the proposed dredging on mangrove communities have been identified from
the effects of sedimentation from smothering of pneumatophores of dredge material. Therefore
sedimentation rates will be monitored routinely. Should sedimentation rates exceed adopted trigger
levels described below the reactive mangrove health monitoring program will be initiated (Section
6.5).
Sedimentation during dredging will be used as a proxy to monitor mangrove health condition during
dredging activities. A mangrove health investigation will be triggered should sedimentation levels at
impact sites display statistically significant differences to reference locations.
6.4.1 Monitoring Sites
Surface Sediment Profiling Sites will be located in areas that have been predicted by modelling to
undergo substantial sedimentation during dredging. Areas where sedimentation is likely to occur at
elevated levels include Stanley Point, Southern Bank at the confluence of South West Creek and West
Creek, Burgess Point and the eastern side of Finucane Island. The number of sites will be determined
prior to dredging during the baseline investigation to ensure suitable statistical power for comparison
between impact and reference sites. Similar number of reference locations will also be established
prior to dredging once number and location of impacts sites are established. Reference locations will
be established at locations of similar mangrove species composition, geomorphology, benthic
composition and elevation above chart datum.
6.4.2 Methods
Sedimentation will be measured using a fixed point to determine changes in sediment deposition
during dredging. Recorded data will be automatically sent to a verified personal computer(s) for
analysis.
Should sediment profiling indicate that sedimentation rates are above adopted trigger levels
following comparison to reference data a Reactive Mangrove Health Monitoring program will be
initiated to identify potential impacts to mangrove communities (Section 6.5).
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The method adopted will be implemented to ensure the following parameters can be accurately
measured:
• Qualitative assessment of sediment grain-size (e.g. gravel, sand, silt, clay);
• Evidence of erosion or deposition, allowing identification of high and low kinetic energy areas;
and
• Sediment deposition height.
6.4.3 Frequency
Monitoring is proposed to be carried out at the following frequency:
• Continuous in situ measurement (daily) one month prior to commencement of dredging;
• Continuous in situ measurement (weekly) during dredging; and
• One month following completion of dredging.
6.4.4 Data Analysis and Reporting
Observable changes in sediment type at the seabed will be recorded and described (for both impact
and reference sites), and will also be considered in light of natural or external processes (e.g.
cyclones, high wind-wave events, dredging in other areas). The method proposed above will give a
quantitative measure of sedimentation.
6.5 Mangrove Health Monitoring Program
Mangrove health has the potential to be adversely affected through smothering of pneumatophores
from increased deposition following resuspension of dredged sediments. Mangrove health checks will
be undertaken should sedimentation rates exceed adopted trigger levels (Section Error! Reference
source not found.).
6.5.1 Monitoring Sites
Monitoring sites will be established at a minimum of four ‘impact’ sites adjacent to the Project dredge
footprint or in an area where substantial sedimentation has been predicted. The number of sites
should be determined to ensure results have a statistical power for comparison between reference
and impact sites. In addition, two ‘reference’ sites, which are comparable to impact sites and located
outside the extent of any predicted impacts from the dredging, will also be established.
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6.5.2 Methods
6.5.2.1 Establishment of Permanent Monitoring Quadrats
A series of permanent monitoring quadrats will be established in the designated impact and reference
locations. The sites will be selected to encompass both low and high elevations, and all significant
community types. At each site, four randomly located 4x4 m quadrats will be established and marked
such that they can be easily revisited.
Separate 2x2 m benthic community health quadrats will also be established in locations where they
are unlikely to be disturbed during monitoring site visits (two per site, located in the intertidal
mangrove zone).
6.5.2.2 Long Term Monitoring
In each monitoring quadrat, the following parameters will be measured and recorded:
• Number and species of each tree/branch within the quadrat.
• Height and diameter of each tree/branch within the quadrat.
• From this, above ground biomass (AGB) estimates will be established.
6.5.2.3 Qualitative Health Assessment
Monitoring of mangrove community health will be achieved using the Duke et al. (2005) classification
system, which determines healthy (green leaves < 10% dead/yellowing leaves), sick (yellow, wilting
leaves, approximately 10-50% dead/yellowing leaves) and dead (> 50% dead/yellowing leaves)
mangrove characteristics in each monitoring quadrat. Photographs and a qualitative description of
health attributes (e.g. disease) will also be taken from each monitoring quadrat.
6.5.2.4 Foliage Density and Health
Health of the mangrove community will also be determined using standard methods for foliage
density (using a foliage densitometer) and compared against baseline conditions. The leaf area of
tagged tree branches in each quadrat will also be recorded and monitored. The number of dead
branches and number of saplings in each quadrat will also be assessed.
6.5.2.5 Benthic Community Health
For each 2 x 2 m benthic community health quadrat, a qualitative description and detailed
photographs will be taken, as well as:
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• Counts of the number of A. marina pneumatophores.
• Counts of the number of R. stylosa roots.
• Counts of the number and types of burrows and mounds.
6.5.2.6 Mangrove mapping
Aerial photography will be used to map the distribution, coverage and species composition of
mangrove habitats situated near the project footprint and in areas of potential indirect impacts.
Aerial photography will be ortho-rectified to allow for determination of mangrove cover. Field
surveys will be used to ground truth the distribution, coverage and species composition of mangrove
community types in areas of change as identified through comparison of aerial photographs.
Mangrove mapping will be undertaken:
• prior to the commencement of the project to provide current information on mangrove
distribution;
• at project milestones including the completion of clearing activities within the dredging and
DMMAs’ footprints; and
• on completion of the project.
Mangrove distribution and cover will be compared to the baseline data to confirm that the area of
direct disturbance of mangrove habitat does not exceed the approved limits.
6.5.3 Frequency
Monitoring is proposed to be carried out at the following frequency:
• Prior to the commencement of the Project;
• Six monthly after commencement of the Project; and
• On completion of the Project.
• In the event that sedimentation trigger levels are exceeded, additional mangrove health
monitoring will be undertaken:
• Immediately (or as soon as practicable) after the exceedance; and
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• Three-monthly thereafter until mangrove health indices have returned to pre-dredge
conditions.
6.5.4 Data Analysis and Reporting
Mangrove health data will be analysed to determine significant differences between impact site data
and reference site data. A significant difference will be defined where the p-value <0.05. If it is
identified that impact sites are being negatively impacted from dredging projects a report will be
submitted to the DEC presenting the data collected and management actions implemented to reduce
the impact.
6.6 Onshore Dredge Material Management Area Monitoring
As indicated in the Onshore Sediment Characterisation Investigation (WorleyParsons 2010) the dredge
footprint was considered to have excess acid neutralising capacity and no onshore management for
ASS was required. However, as previously required by the DEC Contaminated Lands Branch, PHPA
have committed to doing some additional testing during dredging to confirm the results of that study
and to get an appreciation of how sediments behave once disturbed.
6.6.1 Methods
6.6.1.1 Tailwater Discharge Monitoring
The tailwater discharge from the five designated DMMAs that will be used for onshore disposal of
dredged material will be managed and monitored in accordance with the Tiered Monitoring
Framework set out in Section 6.1 and the Routine Marine Water Quality Monitoring Program
described in Section 6.2.
6.6.1.2 Acid Sulfate Soils Monitoring
Excess water from the DMMA’s will be discharged through fixed discharge points. The discharge
water will be monitored to ensure it meets the action criteria outlined in Dewatering Effluent and
Groundwater Monitoring Guidance For Acid Sulphate Soil Areas (DEC 2006b). In addition, Total
Titratable Acidity (TTA), Electrical Conductivity (EC) and pH will be monitored weekly to ensure that
water quality parameters are maintained at a pH > 6 and a TTA < 40 mg/L.
Should the DEC action criteria be exceeded then contingency measures will be employed. If the
monitoring results exceed DEC action criteria then this water will be neutralised in accordance with
the DEC guidelines for the treatment and management of disturbed acid sulphate soils (DEC 2004).
The neutralisation point would be located within the inflow to an alternative DMMA. The pH and TTA
will then be re-measured for validation of neutralisation before final discharge to the harbour.
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Based on the preliminary results there is only a minor risk of any PASS material being encountered. In
order to verify this during the construction operations, the reclaimed material will be sampled from
the dredge pipe and tested for ASS by carrying out confirmatory laboratory testing by NATA approved
methods (such Chromium Reducible Sulphur suite or Suspension Peroxide Oxidation Combined
Acidity and Sulphate suite) on a weekly basis.
6.6.1.3 Dust Monitoring
Daily observations of weather/wind conditions will be undertaken. Dust observations will include
record of whether dust was visible leaving the DMMA boundary at any time during the day.
To reduce dust emissions from the DMMAs as a result of wind erosion of dredged material, these
areas will be revegetated where possible. Particularly, revegetation/stabilisation of berms for these
DMMAs will assist in reducing dust emissions.
6.6.1.4 Noise Management
A noise management plan will be developed in order to undertake construction activities, in
accordance with the Environmental Protection (Noise) Regulations 1997. Measures that may be taken
to reduce noise emissions during dredging and construction are detailed in Section 5.9.2.
Prior to the commencement of dredging and construction activities associated with the DMMAs,
PHPA will inform the local community of the proposed activities, including the proposed schedule
and/or hours of construction works, and potential noise impacts to nearby sensitive receptors. Noise
concerns raised by the local community will addressed through existing PHPA community response
processes.
6.6.2 Data Analysis and Reporting
During the course of dredging, weekly sediment samples will be dispatched to the laboratory and
results combined fortnightly with the water quality reporting for the purpose of determining
compliance over the time series. Water quality time series analysis will be used to determine any
temporal trends in TTA, EC and pH. A final report shall be submitted to DEC detailing the results of the
in-pipe sampling and vertical PASS profiling at the conclusion of monitoring. This will demonstrate the
correlation between the investigation report (WorleyParsons 2010) and actual post-dredge results.
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7. REPORTING
Information management will be a key aspect of the successful execution of the proposed dredging
and disposal program. Numerous environmental reports shall be required to record details such as
the progress of work, monitoring of key physical and environmental factors, incidents, complaints and
their status and resolution, compliance and performance.
If at any time during the course of the dredging/dumping activities, an environmental incident occurs
or environmental risk is identified, all measures must be taken immediately by PHPA and the Dredge
Contractor to mitigate the risk or the impact. The situation is to be reported in writing within 24
hours, to DSEWPaC, with details of the incident or risk, the measures taken, the success of those
measures in addressing the incident or risk and any additional measures proposed to be taken.
Error! Reference source not found. provides a summary of reporting requirements as part of this
DMP.
Table 7-1 Reporting requirement to be undertaken during dredging and disposal activities
Report Name
Contents Responsibility Recipient Frequency/ Schedule
Water Quality
Water Quality Monitoring report
Results of the daily monitoring of turbidity at impact and reference locations as specified in Section 6.2.5.
Commentary on any trigger exceedances and resulting management measures.
PHPA DSEWPaC/DEC Bi-monthly
Surface Sediment Profiling report
Monitoring of sediment deposition using telemetered scanning profile imager.
Commentary on any trigger exceedances and resulting management measures.
PHPA DEC Pre, during and post dredging
Dredging logs
Dredge tracking reports. Dredge Contractor
PHPA Daily
Mangroves
Mangrove Health Monitoring report
Results from mangrove health survey as specified in Section 6.5.3.
Comparison to baseline and reference data.
PHPA DEC Following exceedance of sedimentation trigger
Other Marine Habitats (non-mangroves)
Coral Health Monitoring
Results from coral health survey as specified in Section 6.3.4.
Comparison to baseline and reference data.
PHPA DSEWPaC/DEC Reactive following exceedance of WQ trigger levels
Marine Fauna
Marine The Dredge Contractor must report Dredge DSEWPaC/DEC Following event
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Report Name
Contents Responsibility Recipient Frequency/ Schedule
Fauna Incident Report
any turtle, dugong or cetacean injury or mortality immediately to the Environmental Superintendent.
PHPA shall report any detected mortality of any EPBC listed marine species to DSEWPaC and the DEC within 24 hours of observation.
Contractor
PHPA
Marine Fauna Sighting Report
Species identified, behaviour, occurrence, numbers of individuals and location.
PHPA Internal Following event
Introduced Marine Species
Marine Pest Report
Following completion of each vessel inspection a report will be developed and submitted to PHPA Project Manager.
Dredge Contractor
PHPA As required
Hydrocarbon Management
Hydrocarbon Spill Monitoring
Incident report detailing occurrence and spill clean up management actions.
PHPA DEC Following event
Waste Management
Hazardous records register
Records of hazardous materials received, stored and dispensed shall be maintained and reconciled.
Dredge Contractor
PHPA As required
Incident reporting
The Dredge Contractor shall report any incident of wastes entering the marine environment to the PHPA as soon a possible (but within 48 hours) and implement appropriate clean up procedures.
Dredge Contractor
PHPA As required
Offshore Disposal Ground Management
Progress Report
Plotting sheets including the following information to be retained for audit purposes:
• the times and dates of when each disposal run is commenced and finished.
• the position (as determined by GPS) of the vessel at the beginning and end of each disposal run, with the inclusion of the path of each disposal run.
• a means of estimating the volume of dredged material (in cubic metres) dumped and quantity in dry tonnes at the disposal ground for the specified disposal period.
Dredge Contractor
PHPA Weekly
Bathymetry Investigation Report
A report on the bathymetric survey will be provided to DSEWPaC within two months of the final bathymetric survey being undertaken.
This report will include a chart
Dredge Contractor / PHPA
PHPA/DSEWPaC Two months before dredging/disposal is due to be completed.
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Report Name
Contents Responsibility Recipient Frequency/ Schedule
showing the change in sea floor bathymetry as a result of disposal and include written commentary on the volume of dumped material that appears to have been retained within the spoil ground.
On completion of dredging and disposal.
Annual Reporting
To facilitate annual reporting to the International Maritime Organisation, PHPA must report to DSEWPaC by 31 January each year, including on the day of the expiry of the Sea Dumping Permit or completion of all dredging under this permit, information in Appendix 2 to this permit, or in a format as approved by DSEWPaC from time to time.
PHPA DSEWPaC Annually by 31 January each year.
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8. AUDITING
A compliance audit schedule will be developed based on the conditions contained within the various
approvals documents. PHPA will submit to DSEWPaC and the DEC an environmental compliance
report as required following approval of the Project.
Each environmental compliance report will address each element of the audit program approved by
DSEWPaC and the DEC and will be prepared and submitted in a format acceptable to both
organisations.
The environmental compliance report will:
• Be endorsed by signature of PHPA’s Managing Director or a person, approved in writing by
the DEC, delegated to sign on behalf of PHPA’s Managing Director;
• State whether PHPA has complied with each auditing requirement;
• Provide verifiable evidence of compliance with each condition and procedure contained
within the ministerial approval documentation;
• State whether PHPA has complied with each key action contained within the DMP;
• Provide verifiable evidence of conformance with each key action contained within the DMP;
• Identify all non-compliances and non-conformances and describe the corrective and
preventative actions taken in relation to each non-compliance or non-conformance;
• Review the effectiveness of all corrective and preventative actions taken on a monthly basis;
• Describe the state of implementation of the Project; and
• Provide details on record keeping for auditing purposes e.g. dredging vessel logs outlining
dates/times and position of dredging and disposal runs, volumes of dredged material
disposed, etc.
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9. REFERENCES
ANZECC/ARMCANZ (2000). Australian and New Zealand Guidelines for Fresh and Marine Water
Quality.
ANZECC/ARMCANZ (2000). Water Quality and Monitoring Guidelines. National Water Quality
Management Strategy.
BHPBIO (2009). Environmental Referral Document - Nelson Point Dredging, RGP6 Port Development,
Port Hedland. Assessment on Referred Information.
Biota Environmental Sciences (2008). A Flora and Fauna Assessment of RGP5 Spoil Areas A and H, Port
Hedland Harbour. Report prepared for Sinclair Knight Merz and BHP Billiton Iron Ore.
Commonwealth of Australia (2009). National Assessment Guidelines for Dredging. W. Department of
the Environment, Heritage and the Arts. Canberra.
DEC (2003). "Contaminated Sites Management Series: Assessment Levels for Soil, Sediment and
Water."
DEC (2006). Background quality of the marine sediments of the Pilbara coast. Marine Technical Report
Series 1.
Department of Environment and Conservation (2006). Contaminated Sites Management Series -
Community Consultation Guideline. Land and Water Quality Branch.
Department of Environment and Heritage (2006). Australian National Guidelines for Whale and
Dolphin Watching 2005, Department of the Environment and Heritage: 20.
DoE (2006). Pilbara Coastal Water Quality Consultation Outcomes: Environmental Values and
Environmental Quality Objectives. Western Australia.
Duke, N., et al. (2005). "Herbicides implicated as the cause of severe mangrove dieback in the Mackay
region, NE Australia - serious implications for marine plant habitats of the GBR World Heritage Area."
Marine Pollution Bulletin(51): 308-324.
EPA (2001). Guidance for the Assessment of Environmental Factors (in accordance with the
Environmental Protection Act, 1986). Guidance Statement for protection of tropical arid zone
mangroves along the Pilbara coastline No. 1.
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Port Hedland Port Authority South West Creek Dredging Approvals – ERD FRAMEWORK
EPA (2009). Environmental Assessment Guideline 3: Protection of Benthic Primary Producer Haitats in
Western Australia's Marine Environment. Perth, WA, Environmental Protection Authority.
GHD (2007). Long Term Dredge Material Management Plan. Brisbane.
Hope Downs Management Services (2002). Hope Downs Iron Ore Project - Port and Rail - Public
Environmental Review.
HPPL (2008). "HPPL Water Quality Baseline Report." (Report prepared for HPPL by WorleyParsons).
McArthur, C., et al. (2002). Development of guidelines for dredged material disposal based on abiotic
determinants of coral reef community structure. . Third Specialty Conference on Dredging and
Dredged Material Disposal Coasts, Oceans, Ports, and Rivers Institute (COPRI) of ASCE Orlando, FL
USA.
National Oceanic and Atmospheric Administration (2006). Small Diesel Spills (500-5000 gallons).
PHPA. (2001). " Facilities and Port Services: Description." from http://www.phpa.wa.gov.au/.
Port Hedland Port Authority (2003). Annual Environmental Management Plan.
Semeniuk, V. (2007). The mangroves of Utah Point, Port Hedland - regional setting, description,
processes, significance, prediction of port construction impacts, and mitigation. Port Hedland Port
Authority. Port Hedland.
Sinclair Knight Merz (2009). RGP6 Subtidal BPPH Report. Perth, SKM Report Prepared for BHP Billiton
Iron Ore.
Stoddart, J. A., et al. (2005). Rapid high-precision monitoring of coral communities to support reactive
management of dredging in Mermaid Sound, Dampier, Western Australia. Corals of the Dampier
Harbour: Their Survival and Reproduction During the Dredging Programs of 2004. Stoddart J. A. and
Stoddart S.E. Perth, WA, MScience Pty Ltd.
URS (2005). Environmental Monitoring 2004, Maintenance Dredging Campaign. Perth.
WorleyParsons (2010). Onshore Sediment Characterisation Investigation.
WorleyParsons (2010). South West Creek Dredging Approvals - Benthic Primary Producer Habitat
Mapping.
WorleyParsons (2010). South West Creek Water Quality Monitoring Report prepared by
WorleyParsons for Port Hedland Port Authority.
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Appendix 1 – PHPA’s Environmental Policy
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Appendix 2 – PHPA’s Marine Oil Pollution Management Plan