LONG-TERM MAINTENANCE DREDGING MANAGEMENT PLAN
Transcript of LONG-TERM MAINTENANCE DREDGING MANAGEMENT PLAN
LONG-TERM MAINTENANCE DREDGING MANAGEMENT PLAN
PORT OF CAIRNS
JUNE 2019
LTMDMP-01 PORT OF CAIRNS LONG-TERM MAINTENANCE DREDGING MANAGEMENT PLAN
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Table of Contents
1. Introduction.................................................................................................................................. 7
1.1. Purpose, Objectives and Scope ............................................................................................. 8
1.2. Transitional Arrangements .................................................................................................... 9
1.3. Policy Context ...................................................................................................................... 10
1.4. Legislation Pertaining to Maintenance Dredging ................................................................ 12
1.5. Existing Maintenance Dredging Approvals ......................................................................... 12
1.6. General Approvals Requirements ....................................................................................... 13
1.7. Publication and Accessibility ............................................................................................... 14
1.8. Roles and Responsibilities of Port Authority and Port Users .............................................. 14
1.8.1. Port Authority .................................................................................................................. 14
1.8.2. Port Users ........................................................................................................................ 15
1.8.3. Responsibilities for Maintenance Dredging .................................................................... 15
1.8.4. Queensland Maintenance Dredging Schedule ................................................................ 17
2. Port Locality, Setting, and Shipping ............................................................................................ 18
2.1. Existing Port Navigational Infrastructure ............................................................................ 19
2.2. Channel and Swing Basins ................................................................................................... 19
2.3. Berth Layout ........................................................................................................................ 21
2.4. Aids to Navigation ............................................................................................................... 24
2.5. Anchorage Areas and Conditions ........................................................................................ 24
2.6. Tidal Restrictions ................................................................................................................. 24
2.7. Under Keel Clearance .......................................................................................................... 24
2.8. Extreme Weather Condition ............................................................................................... 24
2.9. Tidal Information ................................................................................................................. 25
2.10. Maximum Vessel Size ...................................................................................................... 25
3. Port Environmental Values ......................................................................................................... 26
3.1. World Heritage Area and Marine Park ................................................................................ 26
3.2. Matters of National Environmental Significance ................................................................ 28
3.3. Matters of State Environmental Significance ...................................................................... 29
3.4. Coastal Processes ................................................................................................................ 30
3.5. Mangroves ........................................................................................................................... 31
3.6. Intertidal and Sub tidal Sediments, Sand and Mud Flat ...................................................... 32
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3.7. Seagrass ............................................................................................................................... 32
3.8. Terrestrial Fauna and Birdlife of Conservation Significance ............................................... 35
3.9. Marine Turtles ..................................................................................................................... 36
3.10. Climate ............................................................................................................................. 37
3.11. Fisheries and Aquaculture ............................................................................................... 37
3.12. Cultural Heritage Places and Value ................................................................................. 38
3.13. Locations of Values .......................................................................................................... 38
3.14. Social Values .................................................................................................................... 39
2. Community needs. .................................................................................................................. 39
3.15. Economic Values .............................................................................................................. 39
3.16. Historical Significance ...................................................................................................... 40
3.17. Potential Impacts to Sensitive Areas or Values ............................................................... 41
4. Consultation and Key Issues ....................................................................................................... 41
4.1. Identification of Interested and Affected Parties ............................................................... 41
4.2. Port Advisory Group (PAG) .................................................................................................. 42
4.3. Local Marine Advisory Committee (LMAC) ......................................................................... 43
4.4. Technical Advisory Consultative Committee (TACC) ........................................................... 43
4.5. Future Consultation ............................................................................................................. 46
5. Sediment Assessment ................................................................................................................ 47
5.1. Port Sediment ...................................................................................................................... 47
5.1.1. Physical Properties ........................................................................................................... 47
5.1.2. Chemical Properties ......................................................................................................... 47
5.1.3. Introduced Marine Pests ................................................................................................. 47
5.1.4. Potential Contamination Sources .................................................................................... 48
5.1.5. Sediment Movement and Coastal Process within Trinity Bay ......................................... 49
5.2. Minimisation of Sediment Accumulation and Dredging Need ........................................... 52
5.3. Maintenance Dredging and Disposal Requirement ............................................................ 53
5.3.1. Past Maintenance Dredging ........................................................................................... 53
5.3.2. Present Maintenance Dredging ....................................................................................... 54
5.3.2.1. Annual Siltation Trend ................................................................................................. 55
5.3.2.2. Material Placement Area – Ocean Disposal Site .......................................................... 56
5.3.2.3. TSHD Brisbane .............................................................................................................. 57
5.3.2.4. Grab Dredge - Willunga ............................................................................................... 59
5.3.2.5. Bed Levelling ................................................................................................................ 59
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5.3.3. Future Maintenance Dredging......................................................................................... 60
5.4. Examination of Reuse, Recycling, and Disposal Option ...................................................... 61
5.5. Selected Future Dredging and Disposal Strategy ................................................................ 70
6. Risk Assessment Framework ...................................................................................................... 70
7. Identification and Treatment of Key Risks.................................................................................. 74
8. Environmental Management ..................................................................................................... 76
8.1. Objectives ............................................................................................................................ 77
8.2. Operational Control ............................................................................................................. 78
8.3. Adaptive Management ........................................................................................................ 79
8.4. Contingency Planning .......................................................................................................... 80
8.5. Dredging Program Design, Execution, and Control ............................................................. 80
8.6. Introduced Marine Pests ..................................................................................................... 80
9. Monitoring Framework .............................................................................................................. 81
10. Performance Review and Governance .................................................................................... 83
10.1. Record Keeping ................................................................................................................ 83
10.2. Auditing ............................................................................................................................ 84
10.3. Non-Conformance and Corrective Action ....................................................................... 84
10.4. Internal and External Reporting ...................................................................................... 85
10.5. Access to Reports and Data ............................................................................................. 85
10.6. Continual Improvement and Changes to the LMDMP .................................................... 85
11. Supporting Information ........................................................................................................... 88
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Table of Figures and Tables
Figure 1 LMDM Framework .............................................................................................................. 11
Figure 2 Approvals and Management Plan Schematic ..................................................................... 14
Figure 3 Location of Port and Port Limits .......................................................................................... 18
Figure 4 Port Pilotage Plan Layout ..................................................................................................... 20
Figure 5 Wharf Infrastructure ............................................................................................................ 22
Figure 6 Smiths Creek Wharf Infrastructure ...................................................................................... 23
Figure 7 Regional areas of Commonwealth and State Significance .................................................. 27
Figure 8 Physical environment (Source: Environment North, 2005) ................................................. 31
Figure 9 Seagrass meadows adjacent Beacon 18 during September 2018 ...................................... 32
Figure 10 Seagrass Distribution (Esplanade meadow) 2007 to 2017 (JCU-TropWater, 2018) ........ 33
Figure 11 Seagrass Distribution (Bessie Point meadow) 2007 to 2017 (JCU-TropWater, 2018) ..... 34
Figure 12 Concept Model of Coastal Processes in Trinity Bay (Environment North, 2005) ............. 50
Figure 13 Concept Schematic of Sedimentation Processes in Trinity Bay (Carter, et al 2002) ......... 50
Figure 14 Sedimentation Processes in Trinity Bay (BMT WBM 2016) ............................................... 51
Figure 15 Sediment Budget for Cairns- from WQA17 Report (BMT, 2018) ..................................... 52
Figure 16 TSHD Sir Thomas Hiley - pumping sand to shore near the present Wharf Street ............. 54
Figure 17 Channel Target depths required to address siltation ........................................................ 56
Figure 18 TSHD Brisbane .................................................................................................................... 57
Figure 19 TSHD Brisbane Overflow valve ........................................................................................... 58
Figure 20 Grab Dredge Willunga and barge ...................................................................................... 59
Figure 21 Bed Levelling vessel Pacific Conquest and close up of drag bar ........................................ 59
Figure 21 Placement options assessment in 1990 ............................................................................. 61
Figure 23 Multi criteria options assessment areas 1990 to 2018 ...................................................... 62
Figure 24 Risk Management Process (from MDS, 2017) ................................................................... 75
Figure 25 Management Plan and Approval Structure ....................................................................... 77
Figure 26 Dredge Management and Monitoring elements ............................................................... 78
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Table of Tables
Table 1 Existing Approvals ................................................................................................................ 13
Table 2 Environmental Roles and Responsibilities ............................................................................ 16
Table 3 Port Infrastructure................................................................................................................. 21
Table 4 Matters of National Environmental Significance (MNES) ..................................................... 28
Table 5 Threatened, Migratory and Listed Marine Species (from EPBC Protected Matters Search) 35
Table 6 Marine Turtle Ecology ........................................................................................................... 36
Table 7 Port of Cairns trade statistics FY14 to FY18 .......................................................................... 40
Table 8 Stakeholders .......................................................................................................................... 41
Table 9 Cairns TACC Membership ...................................................................................................... 45
Table 10 Relative Sediment volume for Port of Cairns from WQA17 Report, (BMT, 2018) .............. 52
Table 11 Dredging and Placement Volumes over the Present Permit Period ................................... 55
Table 12 Estimated requirements for land area over 5 year and 10 year planning horizons ........... 63
Table 13 Disposal Options and Relative Assessment against Issues ................................................. 65
Table 14 Risk Assessment Summary- Impacts of Dredging to and from Aspects of Trinity Inlet ...... 71
Table 16 Long-term Monitoring Schedule ......................................................................................... 82
Items in blue underline show linkage via a hyperlink to internal or external content.
DOCUMENT CONTROL PREPARED and APPROVED RELEASED
Version 1 Initial Ports North draft from Guidelines content
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FILE REFERENCE 03-02-03
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1. Introduction
The Port of Cairns is situated at the mouth of Trinity Inlet and is the closest regional city to the Great Barrier Reef.
Since establishment of the Port in around 1876, and the subsequent settlement of Cairns and development
of the adjacent Tablelands for gold and timber, the Port has expanded to accommodate the tourism sector,
which is now its primary industry.
Access to the town and the Port has meant dredging is a key part of the city’s development. Records from
1878 show works to cut the entrance to 15ft at a time when depth at the location of the present day
Wharfs 1 to 3 was in the order of 9 to 13ft deep. Dredging and material management have been, and
continue to be, a core management obligation for the Port as set out in this Plan.
As a Port Authority under the Transport Infrastructure Act 1994, Far North Queensland Ports Corporation
Ltd (trading as Ports North) has obligations which include the need for maintenance dredging to fulfil its
function to provide and operate effective and efficient port facilities and services. To meet this legislative
obligation, Ports North is required to have in place ongoing approvals to ensure an ability to dredge and
otherwise maintain or improve navigational channels to ensure safe navigation within the port channels.
Ports North undertakes maintenance dredging of the Port of Cairns channels, swing basins and berths
through a series of campaigns within each year, commensurate with the scale of sediment accumulation.
Channels may naturally shallow over time due to siltation and sediment transport processes. Maintenance
dredging involves the removal of these sediments that have built up in existing channels and is required to
maintain designated channel depths to ensure the continued efficient passage of vessels utilising the Port.
Most ports, including the Port of Cairns, cannot sustainably function without maintenance dredging.
Maintenance dredging has occurred in Queensland since ports were first established and navigational
depth is critical to facilitate export of commodities and import of a range of goods on which communities
rely, and hence are all reliant on maintained shipping channels (TMR 2016).
The Queensland Department of Transport and Main Roads, through actions required under the Reef 2050
Long-term Sustainability Plan, has developed the Queensland Maintenance Dredging Strategy (QLD-MDS).
In response to those requirements, Ports North has developed this Long-term Maintenance Dredging
Management Plan (LMDMP) which sets the framework for the responsible environmental management of
maintenance dredging at the Port, so as to address the DTMR requirement for a plan to be developed for
each of the Great Barrier Reef ports.
Ports North has recently completed two phases of a comprehensive and robust Environmental Impact
Study process under both Commonwealth and State terms of reference which assessed, through a
contemporary environmental impact assessment process, the capital dredging of the Port of Cairns
scheduled for 2019. This process considered past and future maintenance dredging requirements and the
environmental setting of Trinity Bay, with outcomes of that comprehensive EIS process being directly
applicable to sections of this LMDMP document. It will continue to inform future iterations of this Plan as
described in Section 1.2.
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1.1. Purpose, Objectives and Scope The purpose of this Long-term Maintenance Dredging Management Plan (LMDMP) is to document the
strategy for managing natural sediment accumulation within the navigable waters at the Port of Cairns in a
way that ensures the safe and efficient operation of the Port, the ongoing protection of local environmental
values and the Outstanding Universal Value (OUV) of the GBRWHA, and to address the requirements under
the QLD Maintenance Dredging Strategy (MDS).
Consistent with the objectives of the QLD MDS, this LMDMP has been developed to achieve the following
objectives:
Recognising existing arrangements, whilst outlining the approach for creating a robust, transparent,
long-term framework;
Ensuring that maintenance of navigable depths does not adversely impact local environmental
values, including the OUV of the GBRWHA;
Detailing a robust, transparent long-term planning approach to managing port sediment;
Outlining operational, planning, consultation and monitoring arrangements to inform stakeholders;
and
Providing a framework for maintenance dredging of the Port consistent with the QLD MDS.
In accordance with the MDS framework (TMR, 2017) this LMDMP includes:
A framework for undertaking maintenance dredging operations for the safe navigation and
continued operation of the Port;
objectives (ie. maintain safe navigation, minimise impacts to local values);
an understanding of port-specific sedimentation conditions and processes;
management approaches including dredge avoidance and reduction;
an assessment of beneficial reuse options and a process for ongoing review of these;
long-term dredging requirements based on sediment rates, port safety and port efficiency needs;
a strong stakeholder focus;
a strong risk-based framework for environmental management;
identified material risks detailing the important environmental values that need to be managed,
the outcomes that are sought and the means through which these outcomes will be achieved;
key local controls, including an analysis of relevant local environmental windows;
governance arrangements, including the process for performance auditing against the plan; and.
a long-term focus with continual improvement processes nested within a review framework.
The scope of this LMDMP relates specifically to the Port of Cairns and the maintenance of the swing basin,
berths, marinas, entrance channel and placement of dredged material at an adjacent dredge material
placement area.
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Maintenance dredging is required on an annual basis to address the sedimentary processes that influence
the port infrastructure. It comprises a major portion of Ports North’s operational, maintenance, and
environmental management responsibilities.
1.2. Transitional Arrangements
A Long-Term Management Plan for maintenance dredging has been in place for the Port of Cairns to support
past Great Barrier Reef Marine Park and Sea Dumping Permits as far back as the mid-1990s The two most
recent plans cover the 2005-2010 and the 2010-2020 periods. Development of the QLD-MDS and Guidelines
for Development of LMDMPs recognised that long-term management plans that govern the management
and monitoring of maintenance dredging had been in place for a number of years at a number of the port
locations, and therefore transitional provisions were included in the MDS Guidelines.
Further to that, there are three significant influences which have guided the development and context of this
document:
(a) Existing Port of Cairns LTDSDMP 2010-2020
(b) GBR Marine Park and Sea Dumping Permit term
(c) Cairns Shipping Development Project (CSDP)
These three areas are explained in detail below so as to justify the approach presented in subsequent sections
of this LMDMP, and are described as follows:
(a) The Port of Cairns LTDSDMP 2010-2020 was developed during a two-year period via a robust technical
review process overseen by the TACC. It was subsequently approved by the TACC and Regulatory
Agencies for implementation by Ports North over the term of the Permit approval. At the time of
issue, the approval of the sea dumping permit and associated management plan was the first to be
granted in Australia by the Commonwealth. That Plan addressed the guidelines for long-term
management plans, which were developed through consultation between Australian ports and the
Commonwealth to improve management of sea dumping, and to provide certainty for industry that
longer term approvals could be established to reflect the requirements for locations where there are
ongoing maintenance dredging requirements. That plan has a defined regulatory approval and
compliance status and associated administrative processes for it to be altered. There is limited value
in revising that document and initiating that amendment process timeline at this stage, given the
potential requirements associated with the other two influences.
(b) The existing approval for maintenance dredging under the combined Commonwealth Department of
Environment and Energy (DoEE) and Great Barrier Reef Marine Park Authority (GBRMPA), Sea
Dumping and Marine Parks Permit, as described in Section 1.5, have a term through to mid-2020.
The term of this approval is the primary driver of timelines for management of dredging and
placement at the Port of Cairns The planning for the renewal/new application phase commenced in
2018, inclusive of consideration of how the State requirements (including TMR, Marine Parks, and
DAF) will be addressed, and are likely to utilise the same long-term plan to address the inherent
conditions. Due to this impending renewal/new permit process under Commonwealth requirements,
and the flow-on effect to the associated management plan, there is again efficiency in addressing
that process in parallel with the other influences and the QLD MDS requirements to develop an
LMDMP.
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(c) As an outcome of the Environmental Impact Study (EIS) and approval process completed over the
period between 2012 and 2018 for the Cairns Shipping Development Project (refer to this link CSDP
for comprehensive details), amendment to the present approvals (described in Section 1.5) will be
required during the forthcoming period. This will be required so as to accommodate the channel
design and profile resulting from the capital works, as well as outcomes of the assessments
undertaken during the EIS and detailed project design phases which have included consideration of
a number of aspects of sediment management and monitoring for that Project which are directly
applicable to future management of dredge material from maintenance of the Port. There is a
significant efficiency and benefit to utilising those study outputs whilst addressing the approval and
associated Plan amendments in parallel with the permit application phase described below, during
2019.
This LMDMP, therefore, has a short-term interim focus consistent with the above noted transitional
arrangements, and is presented as a bridging document to enable Ports North to address the immediate
obligations required under the State process of the QLD MDS, for development of an LMDMP, cognisant of
the status of the Port of Cairns LTDSDMP 2010-2020 which continues to have effect till June 2020 (or unless
revoked sooner), and to direct efforts toward a comprehensive and expanded document to support the
impending Commonwealth, GBRMPA and State assessment and approval for the next “permit term” beyond
2020.
It is envisaged that this LMDMP will be assimilated into a combined plan (of an as yet to be specified name),
to accommodate both Commonwealth and State requirements, and this process is to be facilitated by Ports
North through consultation detailed in Section 4, including the TACC and other stakeholders such as TMR,
and those with jurisdiction over the respective Commonwealth and State approvals.
Ports North is committed to transitioning the Port of Cairns LTDSDMP to a subsequent version of this LMDMP,
and to ensure consistency with approach at the other GBRWHA Ports where applicable.
1.3. Policy Context
A range of high level policy requirements now outline the approach to be taken in regard to management of maintenance dredging within Queensland, and this Plan has been developed to align with the following:
i. The Reef 2050 Long-term Sustainability Plan (Reef 2050 Plan) released by the Australian and
Queensland governments in March 2015. It is the overarching framework for protecting and
managing the Reef until 2050. The Plan sets clear actions, targets, objectives and outcomes to drive
and guide the short, medium and long-term management of the Reef. The Reef 2050 Plan includes
a number of port-related actions that make clear the need for port authorities to understand the
sedimentation characteristics of their ports, avoid and reduce impacts of sediment management
where possible and establish sustainable long-term management arrangements.
This LMDMP is consistent with the strategic objectives of the Reef 2050 Plan which seek to
ensure Great Barrier Reef World Heritage Area (GBRWHA) ports adopt a long-term
approach to the planning, consultation, monitoring and reporting of maintenance dredging
activities.
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ii. Queensland’s Maintenance Dredging Strategy for Great Barrier Reef World Heritage Area Ports
provides a framework (as shown in Figure 1) for ports
within the GBRWHA to develop and implement long-
term maintenance dredging management plans. The
framework builds on the current regulatory
requirements to ensure the ongoing protection of the
Reef's values and the continued operating efficiency
of ports within the GBRWHA.
This LMDMP fulfils the expectations of the Queensland
Maintenance Dredging Strategy for Great Barrier Reef
World Heritage Area Ports in terms of long-term
maintenance dredging management plans.
Figure 1 LMDM Framework
It is supported by:
o The Monitoring Program (in the LTDSDMP 2010-2020 and developed by Ports North) which outlines the ambient, impact and adaptive monitoring overseen by the Port Authority. This Program has effect till 2020 and is considered to address the Monitoring Program content for this LMDMP until such time as the relevant plans are assimilated into a combined plan for the next permit term post mid-2020, and;
o The Maintenance Dredging Environment Management Plan which is developed in conjunction with the dredge operator specific for an individual dredging campaign and contains the operational controls for the dredge.
iii. The Ports Australia Environmental Code of Practice for Dredging and Dredged Material
Management sets out a number of environmental principles that Australian ports meet when
undertaking dredging and disposal of dredged material. The principles have been defined on the
basis of ecologically sustainable development principles.
This LMDMP has been developed to ensure alignment with the environmental principles of the
Environmental Code of Practice for Dredging and Dredged Material Management.
iv. The National Assessment Guidelines for Dredging (NAGD) established a scientific assessment
framework to determine if dredge material is suitable for ocean disposal. The Guidelines include
an assessment framework that is applied to ensure the impacts of dredged material loading and
disposal are adequately assessed.
This LMDMP requires the adoption of the NAGD should any disposal of maintenance material at
sea be considered.
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1.4. Legislation Pertaining to Maintenance Dredging
Maintenance dredging programs at the Port of Cairns are subject to Commonwealth and Queensland government laws. The relevance of particular legislation and approvals processes that apply to a proposed dredging project are assessed in the initial planning stage of any proposed campaign, and depend upon the specific nature of each proposed dredging program. The following legislation may be relevant:
i. Environment Protection (Sea Dumping) Act 1981: applies when dredged material is proposed to be placed at
sea.
ii. Environment Protection and Biodiversity Conservation Act 1999: triggered when a development proposal,
which could include maintenance dredging, has the potential to have a significant impact on MNES.
iii. Great Barrier Reef Marine Park Act 1975: dredging or placement of material inside the Marine Park requires
a permit issued by GBRMPA.
iv. Queensland Planning Act 2016: approvals for operational works and environmental authorities (EAs) related
to maintenance dredging.
v. Queensland Marine Parks Act 2004: some port operational works at the Port occurs within the GBR Coast
Marine Park and approvals may be required depending upon the specific location of the activity proposed.
vi. Queensland Environment Protection Act 1994: regulates activities that may impact upon environmental
values and/or cause environmental harm.
vii. Queensland Sustainable Ports Development Act 2015: mandates master planning for priority ports and their
surrounding land and marine areas including areas potentially used for the placement of maintenance
dredging material.
viii. Queensland Coastal Protection and Management Act 1995: provides for the regulation of dredging, tidal
works and other activities in the coastal zone, particularly in coastal management districts and erosion prone
areas. Additionally, the Act regulates the removal of material from tidal water, such as may occur with
maintenance dredging, which typically requires a development permit.
ix. Queensland Fisheries Act 1994: regulates activities that may impact upon both fisheries resources and also
fisheries habitats. A series of departmental policies and guidelines outline the requirements for approvals
that address social, cultural, commercial, and recreational use of the fisheries resource. Where dredging
activity is likely to affect such fisheries habitats, resources or values, a development permit is typically
required.
1.5. Existing Maintenance Dredging Approvals
A number of State and Federal approvals necessary for conduct of maintenance dredging (extraction and removal from tidal waters) or disposal (extraction and placement on land or other areas under tidal waters) apply at the Port of Cairns. The identified approvals triggers are identified as:
· Environmental Authority (EA) - Undertake maintenance dredging of navigational infrastructure.
· Operational Works (Tidal Works) - Disposal of dredged material below high-water mark.
· Marine Park Permit - Maintenance Dredging and Disposal in Marine Park.
· Sea Dumping Permit - Maintenance Dredging and Disposal at Sea.
· Development Approval and Marine Plant Disturbance Permit – removal of marine plants.
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In conjunction with the aforementioned, compliance with obligations is also required with the following:
- General Environmental Duty, under the QLD Environmental Protection Act 1994.
- Duty to Notify, under the QLD Environmental Protection Act 1994.
- General Biosecurity Obligation (GBO) under the QLD Biosecurity Act 2014
The Port currently undertakes dredging to maintain the existing swing basins, channel, marina and fishing
base areas to meet its obligations as an authority under the Transport infrastructure Act 1994, with a portion
of that as maintenance of existing lawful structures (design channel, swing basin and berth pockets).
A Summary of details of past approvals is outlined in the 2005 to 2010 LTMP, and also in the LTDSDMP 2010-
2020.
Details of existing approvals are tabulated below, with detail or copies of the specific approvals being
accessible via the respective agency websites and registers, and/or by request to Ports North.
Table 1 Existing Approvals
Permit No. Duration Description Government Agency
G10/33155.1 17 June 2010
to 1 June 2020
Marine Park Permit Commonwealth
and State
GBRMPA and State
Marine Parks
EPPR00395813 4 October 2013
- ongoing
Environmental Authority-
ERA 16 (1c) Dredging
>100,000t but <1,000,000t yr
State Department of
Environment and Science
(DES, and predecessors)
SD 2010/01 11 June 2010 –
1 June 2020
Sea Dumping Permit Commonwealth Department of
Environment and Energy
(DoEE, and predecessors)
2006CA0478 07-September
2006- ongoing
Development Permit-
Operational Works to
Remove, Damage, or Destroy
Marine Plants
State Department of
Agriculture and Fisheries
(DAF, and predecessors)
1.6. General Approvals Requirements
Most approvals for dredging at either Commonwealth, State, or local level have a contemporary
requirement to have some form of dredging management and monitoring plan, with those of a long
approval duration requiring a more comprehensive long-term plan (i.e. LT-Plan or comparable naming).
Compliance with these approvals and their respective conditions is required. A number of key actions are noted below in addition to the administrative conditions, which are described generally as:
- Have in place a Management Plan, endorsed by the TACC, known as the LTDSDMP 2010-2020;
- Provide reporting on outcomes of pre-post hydrographic surveys;
- The EA has a series of approved plans which show the allowable dredging target depths and typical batter slopes per area;
- Provide notification before and at the end of works;
- Report on monitoring;
- Keep records; and
- Record and respond to incidents and complaints.
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A schematic, showing the interaction between the above noted approvals, and the general approval
requirements for the respective “management plan” documents is displayed in Figure 2.
Figure 2 Approvals and Management Plan Schematic
1.7. Publication and Accessibility
Approved versions of the LMDMP and associated management documents are to be available for use by internal staff via the Ports North intranet. Relevant documents for public access will be available via the Port North website for the duration of the LMDMP
1.8. Roles and Responsibilities of Port Authority and Port Users
There are a number of roles beyond that undertaken by Ports North which influence the demand for and interest in maintenance dredging for the channel and port areas. These are expanded through the following section, so as to place into context the various responsibilities.
1.8.1. Port Authority
Ports North, a government owned corporation, has a Board of Directors to oversee the governance and direction of the organisation. Ports North is responsible for the maintenance of port facilities including shipping channels and berth pockets as the declared port authority for the Port under the Transport Infrastructure (Ports) Regulation 2016. As such, Ports North is the holder of any permits related to maintenance dredging at the Port.
Comprehensive consultation is undertaken with affected and interested stakeholders in relation to Port
operation and maintenance dredging as detailed in Section 4.0. This has included meetings with the TACC
(August 2017 and 2018), the Port Advisory Group (November 2018) and also the LMAC (November 2018) as
part of development of this LMDMP. These groups have provided feedback on key items they consider
important during the past and in the more recent engagement on the LMDMP process, and would require
future consultation (see Section 4.0).
Dredging and Disposal Approvals: Sea Dumping-Marine Parks Permit Env Auth for ERA16
LTDSDMP 2010-2020
Dredging EMP
TSHD Brisbane EMPNavy Base (Willunga
EMP)
Bed Levelling (Willunga EMP, and specific contractors EMP)
Routine Maintenance (Willunga EMP)
Monitoring Programs
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Ports North has a stated policy to manage its ports in a pro-active manner to minimise any impacts from
port operations or new developments. Ports North has a structured environmental program that involves
environmental assessment, monitoring, protection and rehabilitation. It strives for continual improvement
in the control of port and port user activities to maintain a healthy port environment. Independent experts
are typically engaged to provide input to and review management approaches, including LMDMPs. The
detailed environmental policy, procedures and practices are documented in the Environmental
Management System (EMS), which is based on the international standard ISO 14001. The EMS includes a
process for regular internal reviews and audits.
Ports North has responsibilities conferred on it by State legislation (Transport Infrastructure Act 1994 and
Transport Operations (Marine Pollution) Act 1994) for the safe and efficient management of the Port and its
infrastructure, and for managing pollution from shipping activities. The jurisdiction of Ports North at the
Port of Cairns includes all land under the Land Use Plan for the Port of Cairns, and all waters within
designated Port limits.
1.8.2. Port Users
Ports North’s operation of the Port of Cairns does not provide any “umbrella approvals” for the individual activities of port users. Port activities carried out by either port users or operators must comply with all relevant government legislation. The key State legislation for protection of the environment is the Queensland Environment Protection Act 1994. The Queensland Department of Environment and Science (DES) are responsible for ensuring compliance with this Act. Ports North strongly promotes the need for environmental compliance to all tenants. Port users are required to hold all the relevant environmental authorities or licences issued by state administering agencies for their day-to-day activities, which might include Environmentally Relevant Activities such as stockpiling, loading, or unloading in bulk; fuel or chemical storage; and sewage treatment and maintenance.
1.8.3. Responsibilities for Maintenance Dredging
Conduct of the regular hydrographic survey program rests with Ports North’s Surveyor, who, in liaison with the Regional Harbour Master, considers the outcomes of periodic surveys of the channel and swing basin, to inform the General Manager Planning and Infrastructure on the likely need for annual maintenance works. Overall supervision of the dredging or bed-levelling contract between Ports North and the contractor is managed by the GM Planning & Infrastructure. The Hydrographic Surveyor oversees the day-to-day supervision of the contract over the typically four week campaign for the channel. Ports North also offers a contract dredging service to the Department of Defence, with that work conducted by the grab dredge Willunga, supervised by the Manager Plant & Maintenance, consistent with the inner port, marina and fishing base maintenance works conducted by Ports North staff.
Oversight of the environmental management, inclusive of approvals compliance, EMP, and the monitoring
programs rests with the Environment Manager, who also facilitates stakeholder engagement in regard to
approval agencies, and to interested and affected parties in conjunction with staff from the Corporate
Services section where applicable.
The Cairns TACC is managed, and meetings facilitated, by the Environment Manager.
Port Operations staff and the Port Pilots engage regularly with the various levels of port customers and
users, and the Manager Operations or Manager-Operations Compliance and Security facilitates the Port
Advisory Group.
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The Port Operations or workshop staff provide on-site feedback on activities during the inner port dredging
works and can respond to any public queries, acting as a local point of contact for the likes of the
community.
Staff and contractors are responsible for the environmental performance of their activities and compliance
with approvals and statutory obligations relevant to their work. Staff and contractors are also responsible
for complying with the general environmental duty as set out in Section 319 (1) of the Environmental
Protection Act 1994 which states:
“A person must not carry out any activity that causes, or is likely to cause, environmental harm unless the
person takes all reasonable and practicable measures to minimise the harm.”
Table 2 provides a summary of the responsibilities and accountabilities of staff associated with the
implementation of this LMDMP and maintenance dredging operations.
Table 2 Environmental Roles and Responsibilities
Position
Responsibility
Reporting to
Chief Executive Officer (CEO)
Ensure that systems are in place to manage
environmental aspects and impacts.
Responsible for ensuring the organisation is
compliant with legislation.
Board of Directors
GM-Planning &
Infrastructure
Responsible for management of the dredging
contract.
Ports North contact for operational issues
during dredging.
Overall responsibility for Environmental Policy,
strategy, and EMS framework.
Implementation of LMDMP components and
associated documents within dredge contract
and contract supervision.
Chief Executive Officer
Environment Manager Implementation of this LMDMP and
associated management documents. Ensure
environmental management, monitoring,
reporting and auditing responsibilities are
met.
Assist implementation of LMDMP and
associated documents, review of compliance,
and review of management documents.
Responsible for the coordination of
environmental monitoring programs and data.
GM-Planning & Infrastructure
Hydrographic Surveyor Implementation of survey program consistent
with survey standards. Provision of survey
outcomes to inform dredging program.
Supervision of dredge or bed level contract.
GM-Planning & Infrastructure
Port Operations
Manager
General and afterhours contact for the
operations and environment matters (incidents,
complaints).
Chief Executive Officer
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1.8.4. Queensland Maintenance Dredging Schedule
The maintenance dredging schedule for QLD ports is determined by availability of the Trailing Suction Hopper Dredge (TSHD) Brisbane, which is owned and operated by the Port of Brisbane Pty Ltd (BPL). The TSHD Brisbane is utilised by a number of the QLD ports for the majority of maintenance dredging activities.
The process for development of the state-wide schedule was reviewed under the MDS. The schedule is
developed annually in accordance with a Draft QLD Ports Association (QPA) procedure (QPA 2017) which
requires each Port to define its maintenance dredging requirements and complete a port-specific
environmental risk assessment for maintenance dredging. PBPL develops the state-wide maintenance
dredging schedule by taking into account:
The volume of material to be dredged at each port (hence dredging duration)
The urgency of maintenance dredging required by individual ports (i.e. the degree of siltation,
safety issues and schedule of deeper draft ships that may visit the port)
Any permit-specific issues (e.g. permit availability and conditions)
The need to optimise dredge operation (e.g. avoid backtracking between ports)
Opportunities to minimise the dredging duration at each port. Dredge operation is expensive and
operational efficiency is a key management objective
Important ecological and environmental timings.
This process is generally completed in the first quarter of the year once wet season effects (e.g. cyclones,
floods) to both environmental values and siltation levels are understood, and the scale of sediment
deposition, or forecast deposition, becomes clearer.
The schedule, through negotiation between the Queensland Port Authorities, is provided to TMR and
published on their website in accordance with the requirements of the MDS.
At the end of the year annual reporting on outcomes is provided to TMR for completion of the process and
is accessible on the TMR Website.
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2. Port Locality, Setting, and Shipping
The Port of Cairns is the main trading port managed by Ports North. The Port limits shown in Figure 3 are defined in the regulations of the Transport Infrastructure (Ports) Regulation 2005. The Port includes the waters of Trinity Inlet, lower Barron River, Trinity Bay out to Green and Fitzroy Islands and south of Cape Grafton to Buddabado Creek and back along the coastline.
Figure 3 Location of Port and Port Limits
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The Port activities are concentrated around the mouth of Trinity Inlet and Smiths Creek adjacent to the City of Cairns centred on a latitude of 16°55'30.05"S and longitude of 145°46'50.62"E (at Wharf 1).
The Port currently has 73 pile berths for craft up to 18m LOA; the Marlin Marina complex which has 261 pontoon berths for game fishing, dive and recreation; tourist ships up to 80m LOA; 30 reef fleet berths; 10 berths for super-yachts; and berths for commercial shipping.
There are two commercial fishing bases with mooring facilities for 89 ships.
The Royal Australian Navy has a northern base at the Port, which is used by patrol boats, hydrographic survey ships and landing barges.
There are also a large number of private yachts and charter ships that ply daily to the Reef, and barges which service the nearby islands.
The Port operates 24 hours a day, seven days a week.
2.1. Existing Port Navigational Infrastructure
Details are summarised below for the existing port navigational infrastructure (shown in Figure 4 to 6). It includes channels and berths, so as to outline the infrastructure that is required to be maintained, including those that require maintenance dredging. A summary (Table 3) is also provided which outlines the type and size of vessels that utilise the Port and facilities, which indicates the importance of the dredging requirements.
2.2. Channel and Swing Basins
The Port of Cairns includes the dredged entrance access channel which has a designed depth of 8.3m lowest astronomical tide (LAT) and an average width of 90m.
The Entrance Channel has a length of 5.3 nautical miles (nm) and Trinity Channel is 1.8 nm in length from beacon C20 to Cairns number 12 wharf. The wharves are located on the western (city) side of the inlet, with further facilities for smaller craft being located in Smiths Creek.
Mariners are advised that the channel beacons are 180m apart, whilst the channel width is 90m. Mariners are advised that the toe line in the entrance channel varies in the area between C20 and C18 from 40m to 37.5m in width. The sugar ship loader at berth C12 is fitted with a mechanical trimmer, has a maximum outreach to the centre of the chute of 13.52m and a maximum air draft (LAT to horizontal boom) of 16.83m.
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Figure 4 Port Pilotage Plan Layout
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Table 3 Port Infrastructure
Berth
Design depth (metres)
Berth face\(metres)
Wharf height (above datum)
Comments
Entrance channel 8·3
Crystal swing basin Swing basin diameters and depths may be reduced prior to scheduled dredging.
at 360 m 8·3 Maximum length 280m dependant on draft.
at 380 m 7·3 Maximum length 280m dependant on draft.
Navy swing basin 8·3 Swing basin diameters and depths may be reduced prior to scheduled dredging and when navy vessels are double banked at the navy jetty.
at 320 m 8·3 Maximum length 200m depending on draft.
at 310 m 8·3 Maximum length 194m depending on draft.
C1–C6 8·4 595 4·9 Berths C1 to C6 form a continuous quay line. Cruise ships, naval vessels and trawler berths.
C7 9·3 250 5·0 Berths C7 and C8 form a continuous quay line. Containers, bulk fertilizer and break bulk cargo. Max vessel size 40,000 dwt. C8 10·0 5·0
C10 9·3 20 4·8 Tanker berth for oil and LPG and bunkering facilities.
C11 Owned and operated by the Royal Australian Navy (HMAS Cairns).
C12 10·5 190 5·0 Bulk sugar and bulk molasses. Molasses storage capacity 18,600t. Bulk sugar storage 234,000t. Sugar loading rate 1600 tph.
CFB 1&2 Commercial Fishing Base – CFB1 has 54 moorings and CFB2 35 moorings.
Barge ramp Two barge ramps. Max barge size 55m x 13·2m or 500 grt.
Smiths Creek Wharf # 1
8·5m 53·4 3·7 General cargo berth. Max vessel size 80 m.
These depths are subject to change throughout the year and the relevant Notices to Mariners provides for advice on latest information.
2.3. Berth Layout
The berth arrangements consist of 12 main wharves, along with three marinas comprising numerous individual berths as shown in adjacent figure. For the main wharf berths, a berth pocket is maintained adjacent to each wharf to depths as per Table above.
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Figure 5 Wharf Infrastructure
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Figure 6 Smiths Creek Wharf Infrastructure
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2.4. Aids to Navigation
The beacons marking the entrance channel are in nine pairs with a tenth beacon on the eastern side of the channel. The leading lights (in line bear 209·4°) and are spaced 900m apart.
The rear lead has a nominal range of 11nm and is positioned on the roof of the Shangri-La Hotel
adjacent to the Marlin Marina complex. Two leads for the Trinity Inlet harbour comprise both front
and rear leading lights located on single pile beacons. The distance between these beacons is 635m.
2.5. Anchorage Areas and Conditions
Vessels are only to anchor in the position and area designated by the VTS centre. Upon anchoring, vessels are to advise Cairns VTS of their anchoring time and position and are to maintain a continuous listening watch on VHF channel 16 and any other channels as instructed. Vessels are to report to the VTS if dragging anchor and are not permitted to immobilise engines without the written approval of the Regional Harbour Master. Anchorages outside of the pilotage area vessels waiting to enter the Port may wish to proceed to anchor and vessels may anchor at one of 8 locations designated as CA1 to CA6, and CS1 & CPS2. These positions afford anchorage in 10 to 15m of water with good holding. Prevailing winds are up to 20 knots south-easterly with up to 1·5 knots of current.
Four anchorage areas are available within Cairns Harbour for smaller vessels. The holding ground at all
harbour anchorages is mud of varying depths over a hard base. Masters of vessels at these anchorages
are responsible to ensure that sufficient depth of water is present to maintain an under keel clearance
of no less than 0.3m at all times.
2.6. Tidal Restrictions
Due to the strength and set of the currents and the confined swinging basin, large ocean going ships 175m LOA and greater should only berth and sail at high or low water slack. Vessels 175m LOA or less may be berthed on either a flood or ebb tide if the tidal range is 1.2m or less. Vessels 175 LOA or less should only sail at high or low water slack.
2.7. Under Keel Clearance
Ships are not to enter, depart, or manoeuvre within the pilotage area unless tide, weather, transit time, and traffic conditions allow the minimum UKC to be maintained until the ship is clear of the pilotage area. The Regional Harbour Master is to be consulted for determining the tidal window for the planned movement of a draft-restricted ship in the Port.
The master is to ensure that the ship maintains a minimum UKC of at least 0.3m while alongside any berth.
This may require loading operations to be adjusted to suit UKC conditions. Loaded ships may be draft
restricted for movements. The design depth of the channel is 8.3m but may be less than this between
scheduled dredging. Vessels conducting dredging operations are exempt from under keel restriction. UKC
limit for dredgers is set at 0.3m.
2.8. Extreme Weather Condition
The prevailing winds tend to be easterly to south easterly. Although calmer conditions occur during the winter months, they may become very difficult during the summer months when the sea breeze augments the prevailing south easterlies. As a general rule high windage vessels will not
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be moved when the wind speed exceeds 25 knots. Similar conditions present serious problems when coupled with a flood tide.
A tropical cyclone watch message is issued when a cyclone or potential cyclone is expected to affect
conditions in the area within the next 48 hours and is reviewed every three hours. An extreme
weather event warning message is issued when a cyclone or potential cyclone is expected to affect
conditions in the area within the next 24 hours and is reviewed every three hours. In the event of a
cyclone threat the Regional Harbour Master will take action to ensure the safety of shipping by
establishing a maritime control centre (MCC).
During cyclone conditions, good water can generally be found in the centre of all creeks designated as
cyclone refuges with the exception of Chinaman Creek. All due care must be exercised when
navigating within these creeks. The Cairns Extreme Weather Contingency Plan applies and is overseen
by the Maritime Safety Queensland (MSQ) website.
2.9. Tidal Information
Cairns is a standard port in the Queensland Tide Tables.
- An automatic tide gauge is located at Trinity wharf number 7. - After heavy rain and during the ebb tide a strong set to the east may be experienced in the channel
between beacons C7 and C9. This set is caused by the run-off from the Barron River estuary. - On the flood tide, a south-westerly set is experienced in the channel between beacons C9 and C17;
it then becomes more south-south westerly following the cut of the channel. After passing beacon C20, a more southerly set is evident.
- The ebb runs north between beacons C17 and C20. The ebb is more pronounced after seasonal rain and on spring tides. In general the ebb tide is stronger than the flood.
These tidal patterns and parameters influence sedimentary process on a regular cycle.
2.10. Maximum Vessel Size
The Port limits ship size to 200m LOA, beam 32·5m. Passenger ships in excess of 200m LOA, if twin screw
single rudder configuration, and in excess of 240m LOA if twin screw and twin rudder configuration, may be
accepted on written application to the Regional Harbour Master (Cairns). Further exceptions to these limits
may be allowed, but only after a successful assessment through receipt of vessel owner/operators risk
assessment and the successful completion of full bridge simulation exercises conducted by Ports North
pilots and assessed by the Regional Harbour Master (Cairns).
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3. Port Environmental Values
Values of the Port area are described in detail within the LTDSDMP 2010-2020, and also in more recent
detail in the Cairns Shipping Development Project (CSDP) Revised Draft Environmental Impact Statement
(RD-EIS). A summary of key components is outlined below within the context of dredging activity. To
effectively manage sediment and dredging activities at the Port Cairns it is essential to understand the
environmental, social, and cultural values of the Port and the surrounding area. The commercial activities
were discussed previously in Section 2.
The focus is on values that are considered important or notable at a national, regional or local level. The
aim is to provide a useful level of detail and relevance to management planning. Values are described for
the broader area incorporating the Port limits and adjacent environs. More detailed information regarding
these values can be found in either of the LTDSDMP 2010-2020 or the Cairns Shipping Development Project
(CSDP) Revised Draft Environmental Impact Statement (RD-EIS).
3.1. World Heritage Area and Marine Park
The values for which the Wet Tropics and also the Great Barrier Reef World Heritage Areas were prescribed prevail in the immediate vicinity of the Port, where the rainforest and reef areas meet. Therefore, a number of the components of the criteria for the respective world heritage values are apparent.
The Port of Cairns and surrounding port limits comprise a diverse range of ecosystems and habitats of
significance to the area and include the Wet Tropics and Great Barrier Reef World Heritage Areas. These
habitats support a range of flora and fauna, including a number of threatened and/or migratory species.
There are two World Heritage Areas (WHA) in and around the Port of Cairns: the Wet Tropics WHA and the
Great Barrier Reef WHA.
The Wet Tropics WHA extends into the port limits, though no Strategic Port Land is included within this
World Heritage Area.
The Great Barrier Reef WHA covers the waters to the low water mark along the coastline and extends into
Trinity Inlet. The majority of land above high water within the Port is beyond the GBR WHA.
The Great Barrier Reef Marine Park is also located along the coastline and overlays portions of the Channel
and DMPA, with an exclusion for a portion of the entrance channel. The seaward port limits are within the
Marine Park, as are upstream estuarine areas of the lower Barron River, but the operational port area is
excluded from GBR Marine Park zoning.
The GBR Region overlies the port limits from the low water mark along the coast, but does not include the
internal waters of the state, i.e. landward of the territorial sea baseline which is mapped as a closing line
approximately at Wharf 4.
The WHA and GBR Marine Park boundaries are mapped for the Port of Cairns in Figure 3.
The GBRWHA was inscribed as World Heritage in 1981 in recognition of the range of natural and cultural
heritage that contributes to the OUV of the property. The four natural heritage criteria that the GBRWHA
satisfy are its geological phenomena; ecological and biological processes; aesthetics and natural beauty;
and biological diversity, including the threatened species it supports.
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The GBRWHA listing document identifies specific examples of values/attributes underpinning each criterion
for OUV. Generally the examples of values/attributes are not location specific and therefore do not
specifically define marine ecological values/assets supported in the PoG. Of the criteria for which the
GBRWHA is listed, the PoG supports the following:
Coral reefs;
Lagoonal benthos;
Seagrass meadows and mangrove ecosystems;
Habitats for threatened species;
Coastal/continental islands of exceptional natural beauty; and
Many species of coral, macroalgae, crustaceans, polychaetes, molluscs, phytoplankton, fish,
seabirds, mammals and reptiles.
The integrity of the GBRWHA and the value of these attributes are supported by the size of the property
and its potential for effective conservation management. The integrity of marine habitats varies throughout
the Cairns region. While some are largely intact, including most of the Port area, nearshore shoreline
locations along Trinity Inlet and within the operational Port areas are generally in a modified condition.
Figure 7 Regional areas of Commonwealth and State Significance
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3.2. Matters of National Environmental Significance
The Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) provides for the protection of Matters of National Environmental Significance (MNES). Table 4 lists MNES and describes their potential relevance to maintenance dredging activities at the Port. The locations of MNES of relevance to maintenance dredging activities are shown in Figure 10. Figure 10 also includes the mapped extents of coral reef and seagrass meadows (maximum recorded extent to 2016), as these are considered the major sensitive ecological receptors of relevance to maintenance dredging activities and provide habitat for several species listed as MNES.
Relevant MNES to the Port are the GBRWHA/National Heritage Place and threatened species and migratory
species and are summarised below.
Table 4 Matters of National Environmental Significance (MNES)
MNES Description
World Heritage Sites and National Heritage Places
GBRWHA extends throughout the Great Barrier Reef region and includes most of Port. The GBRWHA is listed as a National Heritage Place.
Great Barrier Reef Marine Park (GBRMP)
The GBRMP is located offshore of the Port and the outer channel and DMPA activities are located in the GBRMP.
Nationally threatened species and ecological communities (including marine turtles and whales)
The EPBC Act protected matters Search tool identified: - Threatened marine ecological communities occur within study area; - Listed species known or likely to occur near the study area include
marine turtles, dolphins and dugongs; - Numerous protected species of sea snake, pipefish and seahorse
occur or could occur in the Port (none of these are considered threatened under EPBC or state legislation).
Migratory species (including dugong, whale shark and several threatened marine megafauna species)
Commonwealth marine species The Commonwealth marine area is located offshore of the Port and activities are not located in this area.
Wetlands of international importance (Ramsar site)
There are no Ramsar sites within the vicinity of the Port.
GBRWHA: dredging activities will be carried out in the GBRWHA which will result in temporary impacts to
water quality near the dredge loading site during dredging and effects to benthic communities within the
direct impact footprint. These are suggested to be of a temporary nature. Significant impacts to
biodiversity values are not expected and significant impacts to the GBRWHA are not expected in the
context of EPBC Act Significant Impact Guidelines 1.1 (DEWHA 2009).
OUV: maintenance dredging is not expected to impact flora, fauna, or have flow-on effects to threatened
species. The proposed dredging is also not expected to affect the property’s geological phenomena, or
significantly impact the ecological or biological processes. The dredging works will not permanently alter
the natural beauty of the property beyond the dredge campaign and will not result in greater vessel
occupancy or additional permanent infrastructure. Therefore, impacts to the OUV are not expected from
the maintenance dredging activity.
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Threatened and Migratory Species: the proposed dredging activities are not expected to lead to significant
direct or indirect effects to listed threatened or migratory species in accordance with the EPBC Act
Significant Impact Guidelines 1.1 (DEWHA 2009).
Other MNES: Predicted loading and disposal plumes do not extend into the Commonwealth Marine Area
(including the GBRMP) and resuspension plumes are minor compared to ambient turbidity. Plumes are
remote (several hundred kilometres south of the nearest Ramsar site). No impacts to these MNES are
expected.
3.3. Matters of State Environmental Significance
Matters of State Environmental Significance (MSES), referenced under the State Planning Policy (SPP) 2013, are environmental values that are protected under QLD legislation including the Nature Conservation Act 1992 (NC Act), Marine Parks Act 2004 (MP Act), the Fisheries Act 1994, Environmental Protection Act 1992, the Regional Planning Interests Act 2014, and the Vegetation Management Act 1999 (VM Act). A summary of MSES and their relevance to the Port and most relevant MSES to maintenance dredging are:
High Ecological Significance (HES) wetland communities:
- most of which are based on mapping of seagrass meadows.
Habitat for Endangered, Vulnerable and Near Threatened (EVNT) and special least concern species:
- which is based mostly on seagrass, mangrove and saltmarsh community mapping and the extent of
Mission Bay for key species such as dugongs, sea turtles and nearshore dolphin species.
Note that many of the threatened species and species groups listed under the NC Act are also listed as
MNES. As for MNES, maintenance dredging is not expected to impact intertidal marine habitat areas
and associated listed marine birds.
Wetlands and Watercourses:
- seagrass meadows are listed as wetlands of high ecological significance. In accordance with the
significant residual impact criteria (State of Queensland 2014), significant residual impacts to
seagrass meadows are not expected because:
major direct or indirect impacts to seagrass meadows are not expected;
seagrass meadows with potential to be affected by dredge plumes will be protected by
mitigation measures (Section 10); and
the potential for dredging to introduce invasive species into the wetland (seagrass meadows) is
very low.
Protected wildlife habitat:
- maintenance dredging activities are not expected to lead to significant direct or indirect effects to
protected wildlife habitat. In accordance with the significant residual impact criteria (State of
Queensland 2014), the proposed dredging will not:
lead to a long-term decrease in the size of a local population;
reduce the extent of occurrence of the species or fragment an existing population;
result in genetically distinct populations resulting from habitat isolation;
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result in invasive species establishing that are detrimental to endangered or vulnerable species;
introduce diseases that may cause the population to decline;
interfere with the recovery of a species; or
disrupt ecologically significant locations used for breeding, feeding, nesting, migration or
resting.
Fish Habitat Areas and Highly Protected Zone of State Marine Parks:
- maintenance dredging activities will take place adjacent to the Great Barrier Reef Coastal Marine
Park. Based on significant residual impact criteria for protected areas (State of Queensland 2014),
the proposed dredging will not:
result in exclusion or reduction in the public use or enjoyment of part or all of the nearby
protected areas; or
reduce the natural or cultural values of all or part of the Coastal Marine Park.
State significant residual impact criteria for highly protected zones of State Marine Parks refer
specifically to works to be conducted within these zones. As the proposed dredging falls outside of
these area boundaries, these criteria are not relevant.
Overall, it is expected that maintenance dredging does not lead to significant impacts to MNES or MSES,
especially with the application of appropriate management strategies (Section 8).
3.4. Coastal Processes
Trinity Bay and its natural harbour, Trinity Inlet, are low energy tropical embayments. Trinity Bay is identified as having relatively shallow waters (<10m) between Double Island (north) to Cape Grafton (south). These northerly facing systems are protected from prevailing south-easterly trade winds by Cape Grafton, but remain open to fluctuating northerly winds during summer and periodic cyclone activity.
Key physical processes leading to the transport and distribution of silt and sediment within the study area
have been defined by Carter et al. (2002) and Environment North, (2005) as shown in Figure 8, and
includes:
• Tidal currents (southeast flood, north east ebb);
• Daily easterly breezes;
• South-easterly trade winds (winter);
• North easterly trade winds during summer; and
• Periodic effects of tropical cyclones
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Figure 8 Physical environment (Source: Environment North, 2005)
3.5. Mangroves
Mangrove habitats are a significant and ecologically important feature of the Trinity Inlet marine ecosystem. Within the Inlet, mangroves occupy approximately 3,500ha of which some 3,000ha are well developed mangrove communities. Rhizophora spp. are the dominant fringing mangrove species, with Bruguiera and Ceriops species dominating as the system moves further inland. A total of 21 species of mangrove have been recorded from the Cairns region.
Mangroves dominate the eastern shores of Trinity Inlet, the upper inlet reaches surrounding Admiralty
Island and the shores north of the Esplanade to the Barron River. However, mangroves remain largely
absent from a significant portion of the developed northern foreshore between the Esplanade and the
Public Boat Ramp at Tingira Street, encompassing the Port of Cairns, a distance of some 7.4km.
The Port and adjacent areas directly exposed to dredging are not associated with significant mangrove
communities, with the shorelines consisting of primarily wharves and revetment structures. The proximity
of Port operations to significant mangrove communities ranges between approximately 100-450m.
With the exception of Admiralty Island, the landward fringes of almost all the mangroves of the Trinity Inlet
system are experiencing substantial encroachment due to adjacent land uses. A significant proportion of
these pressures are attributable to agricultural uses (sugar cane), followed by residential, commercial and
industrial uses.
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3.6. Intertidal and Sub tidal Sediments, Sand and Mud Flat
The intertidal soft sediment habitats, particularly those adjacent to the Esplanade, provide habitat for a high diversity of birds and a significant location for use by migratory waders. These sand and mudflats provide important feeding and roosting habitat and represent a readily accessible area frequented by scientists and the general public as an educational and recreational resource.
Largely undescribed within the existing survey knowledge, subtidal soft sediments comprise the majority of
benthic habitats within the Cairns Port limits and wider Trinity Inlet area. High turbidity and low light
regimes preclude the establishment of significant sub tidal seagrass beds, or ‘reef’ communities (coral,
sponge, algal, etc).
These animals are particularly important as prey items for many of the species that are exploited
commercially (e.g. prawns, bottom-feeding fish).
3.7. Seagrass
Seagrass plays a vital role in coastal ecosystems. An example of intertidal meadow is shown in Figure 9,
immediately beside the dredged channel. Such meadows provide food and shelter for diverse organisms,
and provide a nursery ground for juvenile fish, prawns, and crabs and help to stabilise coastal sediments, as
well as to trap and recycle nutrients. Seagrass beds can survive entirely immersed in seawater and can
typically be found in tropical waters in less than 10 m depth.
Seagrass in the Cairns Harbour has been monitored yearly in a joint program between the Port and DAF or
James Cook University. An annual survey in around Oct-Nov has taken place since 2001, and patterns of
change over that period shown in Figures 10 and 11. This program has been one of the most extensive
seagrass monitoring programs undertaken in Queensland, providing valuable information on the natural
variability in seagrass meadows. This long-term annual seagrass monitoring has been continued as an on-
going indication of the environmental health of the port.
Seagrass meadows show variations between seasons and years, reflecting changes in environmental
conditions. Reductions in seagrass can occur due to natural events such as cyclones and floods or due to
human influences. The area of seagrass in Cairns Harbour typically varies around an average of 1,000ha.
Figure 9 Seagrass meadows adjacent Beacon 18 during September 2018
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Figure 10 Seagrass Distribution (Esplanade meadow) 2007 to 2017 (JCU-TropWater, 2018)
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Figure 11 Seagrass Distribution (Bessie Point meadow) 2007 to 2017 (JCU-TropWater, 2018)
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3.8. Terrestrial Fauna and Birdlife of Conservation Significance
The waters of Trinity Inlet provide potential habitat for a number of fauna species of conservation or economic importance as described below. This section reviews the likely presence of marine species of conservation significance in Trinity Inlet and discussion of those species that may be impacted by dredging or spoil disposal.
Species status under both the Environment Protection and Biodiversity Conservation Act (EPBC Act) and
Nature Conservation Act (NC Act) are provided where applicable.
Table 5 Threatened, Migratory and Listed Marine Species (from EPBC Protected Matters Search)
Scientific Name EPBC Act Status NC Act Status Preferred Habitat Likelihood of Presence
Mammals
Balaenoptera musculus Blue Whale
Endangered, Migratory, Cetacean
- This species is predominantly an offshore pelagic species.
Unlikely
Megaptera novaeangliae Humpback Whale
Vulnerable, Migratory, Cetacean
Vulnerable During spring, travels from Antarctic feeding grounds to breeding grounds in the Great Barrier Reef. The Trinity Bay area is not a known aggregation site for the species, however, it is within the migratory path of the species.
Likely
Balaenoptera edeni Bryde's Whale
Migratory, Cetacean
- This species is predominantly an offshore species.
Unlikely
Dugong dugon Dugong
Migratory, Listed, Cetacean
Vulnerable Predominantly shallow coastal waters in association with seagrass beds.
Likely
Orcaella heinsohni Australian Snubfin Dolphin
Migratory, Cetacean
Rare Shallow coastal waters of less than 20m depth. Often associated with tidal riverine and estuarine systems, enclosed bays and coastal lagoons.
Likely
Orcinus orca Killer Whale
Migratory, Cetacean
The species is predominantly associated with continental shelf and slope environments. While it inhabits all oceans of the world, it is most abundant in temperate waters.
Unlikely
Sousa chinensis Indo-Pacific Humpback Dolphin
Migratory, Cetacean
Rare Shallow coastal waters of less than 20m depth. Often associated with tidal riverine and estuarine systems, enclosed bays and coastal lagoons.
Likely
Reptiles
Caretta caretta Loggerhead Turtle
Endangered, Migratory, Listed
Endangered Waters with both hard and soft substrates including rocky and coral reefs, muddy bays, sandflats, estuaries and seagrass meadows.
Likely
Chelonia mydas Green Turtle
Vulnerable, Migratory, Listed
Vulnerable Marine, tropical and warm subtropical seas of northern Australia. Shallow benthic foraging habitats containing seagrass and/or algae including inshore seagrass beds.
Likely
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Scientific Name EPBC Act Status NC Act Status Preferred Habitat Likelihood of Presence
Dermochelys coriacea Leatherback Turtle
Endangered, Migratory, Listed
Endangered The leatherback turtle are generally considered to be an oceanic species with little nesting occurring in Australia. The individuals that occurin Australian waters are considered to be foraging migrants.
Unlikely
Eretmochelys imbricata Hawksbill Turtle
Vulnerable, Migratory, Listed
Vulnerable Coastal marine waters with a foraging preference for rocky reef and coral reef habitats. Breeding predominantly on beaches in the Gulf of Carpentaria and the Great Barrier Reef Islands.
Likely
Lepidochelys olivacea Olive Ridley Turtle
Endangered, Migratory, Listed
Endangered Benthic and pelagic foraging habitats ranging from 1 – 100m depth. Scattered nesting records on beaches of inshore islands in Arnhem Land and the Gulf of Carpentaria.
Likely
Natator depressus Flatback Turtle
Vulnerable, Migratory, Listed
Vulnerable Inshore coastal waters of northern Australia with a preference for shallow, soft-bottomed sea bed habitats away from reefs. Breeds exclusively on Australian beaches. On the east coast mainland major nesting sites occur from Bundaberg to Mackay.
Likely
Crocodylus porosus Salt-water Crocodile
Migratory, Listed Vulnerable Tidal reaches of rivers between Gladstone and Cape York. Also occur along beaches and offshore islands in the Great Barrier Reef and in freshwater lagoons, rivers and swamps.
Likely
Sharks
Pristis zijsron Green Sawfish
Vulnerable - Marine/ Estuarine. Typically inhabit inshore coastal areas in muddy or sandy-mud soft bottom habitats. Most common in tropical and sub-tropical waters.
Unlikely
Rhincodon typus Whale Shark
Vulnerable, Migratory
- The whale shark prefers pelagic environments near the continental shelf. Forms aggregations in areas of high seasonal food resources – particularly at Ningaloo Reef (Western Australia)
Unlikely
3.9. Marine Turtles
Marine turtles are long-lived and late maturing with maturity reached at between 30 and 50 years of age (Miller, 1996). The foraging habitats and preferred items of the various marine turtle species are described. The Trinity Bay area provides potential foraging habitat for flatback turtles, Olive Ridley turtles, loggerhead turtles and green turtles. Such habitats are widely distributed throughout the Great Barrier Reef.
The sub-tidal areas of Trinity Bay do not support extensive seagrass beds, principally due to the elevated
turbidity levels. The seagrass beds are largely restricted to the intertidal and very shallow sub-tidal areas
and it is these areas that provide the main foraging habitat for green turtles.
Trinity Bay is not recognised as a major nesting area for any marine turtle species. Foraging habitats and
preferred food items of the various marine turtle species are also shown.
Table 6 Marine Turtle Ecology
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Turtle Species Foraging Habitats Preferred Food Items Reference
Green turtle (Chelonia mydas) Shallow coastal area, in particular seagrass beds.
Seagrass and seaweeds although juveniles are also carnivorous.
Brand-Gardner et al. (1999)
Hawksbill turtle (Eretmochelys imbricata)
Rocky reef and coral reef habitats. Algae, seagrass and sponges. Limpus (2009a)
Flatback turtle (Natator depressus)
Shallow coastal environments including rocky reef and sedimentary habitats.
A wide variety of soft bodied animals including soft corals, sea pens, sea cucumbers, jellyfish and other large plankton.
Limpus (2007)
Loggerhead turtle (Caretta caretta)
A wide range of intertidal and subtidal habitats including coral and rocky reefs, seagrass meadows, and unvegetated sand or mud areas.
Although their diet is diverse, typical items include bivalve and gastropod molluscs and crabs.
Limpus (2008a)
Olive Ridley turtle (Lepidochelys olivacea)
Principally shallow unvegetated coastal environments.
Principally feeds on gastropod molluscs and crabs.
Limpus (2008b)
Leatherback turtle (Dermochelys coriacea)
Oceanic environments from the sea surface to the seabed.
Principally feeds on colonial tunicates such as Pyrosoma spp., jellyfish such as Catostylus spp. and other soft-bodied invertebrates.
Limpus (2009b)
The seagrass meadows are known to be used periodically by turtles for feeding. Turtle species in the region
include green turtles (Chelonia midas), flatback turtles (Natator depressa), hawksbill turtles (Eretmochelys
imbricata) and loggerhead turtles (Caretta caretta). Turtle sightings are rare but periodically reported,
however, the area is not considered to provide a suitable nesting area for turtles. The seagrass meadows
represent a potential food source for dugongs, but they are not regularly observed in the channel or inner
port areas and occur more toward Cape Grafton or northern beaches areas. The large areas of mangroves
provide habitat for crocodiles (Crocodylus porosus) and these have been observed regularly. Crocodiles are
listed as a vulnerable species in the regulations of the Nature Conservation Act 1992.
3.10. Climate
The Port of Cairns is located in one of the highest rainfall zones in Queensland and consequently is subject to a distinct dry season, and the onset of the wet season from late November through to April where tropical extreme weather events may occur. High catchment river flows occur, with Cairns Harbour and adjacent coastal zone becomes less saline and sediment enriched system. Such climate provides high rainfall conditions suitable for the presence of tropical rainforest and a rich biodiversity of flora and fauna throughout adjacent areas along the Malbon-Thompson Range and Lamb Range areas, which are also listed Wet Tropics World Heritage areas.
3.11. Fisheries and Aquaculture
Commercial fishing activities are restricted to gill netting, with target species being barramundi, grunter, and salmon. Mud crabs are also commercially sought.
A net-free zone was established in the mid-2000s for the Inlet, and expanded in 2017 for the foreshore area, adding a greater level of protection to inshore fisheries resources.
The coastal prawn trawl fleet operate from Cairns and there is an active fishery off the northern beaches.
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Recreational fishing is a regular activity in the Trinity Bay area, where vast numbers of locals and visitors access the foreshore and marine infrastructure, along with a viable inshore fishing charter fleet that operates within the Inlet.
Two aquaculture facilities are located within the Inlet, with one of those drawing water from the Smiths Creek area for a land-based tank aquaculture and research facility.
Their operations are licensed under the Environmental Protection Act 1994 and the Fisheries Act 1994 with new facilities also potentially requiring approval from the Great Barrier Reef Marine Park Authority. The impact to the environment from aquaculture relates to a potential deterioration of water quality caused by the elevated nutrient levels from terrestrial pond water discharge and faecal build-up beneath culture operations. A water intake to one of the aquaculture farms is located within the Smiths Creek area, and a number of local marine and aquaculture operators access the port facilities to collect saltwater by tanker truck.
3.12. Cultural Heritage Places and Value
The cultural values of the Trinity Inlet area were described in the 2005-2010 LTDSDMP, and represent the current situation. These values were based on the ethnographic study compiled by David (1994), and was undertaken in close consultation with the Traditional Owners of lands surrounding the Inlet. Though the study was generally confined to a relatively small area in the north-eastern section and the coastal margins of the Trinity Inlet (David estimated that his survey probably included about 5% of the sites that could be recorded), much of the material in it is relevant to the wider Trinity Inlet catchment.
Northern Archaeology Consultancies (1999; reported in Environment North, 2005), reported that Aboriginal
people have occupied North Queensland well in excess of 20,000 years, based on archaeological evidence.
However little was known of the pre-contact history of the Trinity Inlet catchment area. Aspects of the
post-contact Aboriginal history of the Trinity Inlet area have been documented in a number of sources.
Based on David (1994) and other work,(especially Northern Archaeology Consultancies (1999) as reported
in Environment North (2005), it appears that Trinity Inlet remains a significant cultural and economic
resource for Aboriginal people of the Cairns region, including traditional and historical owner groups
(Yirrganydji, Gimuy Yidinji, Mandingalbai Yidindji, Yidindji, Gunggandji and Giangurra).
3.13. Locations of Values
Environment North (2005) listed locations within the Trinity Inlet area known to have significance for Aboriginal people. These include places used for hunting, fishing, shellfish gathering, mythological locales and rock art sites. The areas which were reportedly held most highly with meaningful regard by Aboriginal people are (the list is not exhaustive and in many cases it is not appropriate to disclose the location of cultural sites):
the Cairns Esplanade - this area was extensively utilised as a traditional shellfish gathering place
and was the location of an early Aboriginal camp;
the Trinity Inlet wetlands – several Aboriginal groups have made and continue to make extensive
use of the Inlet’s biological resources, which are harvested according to traditional methods;
Admiralty Island - this area has been noted as an important food gathering point, particularly for
crab and shellfish;
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Bessie Point - this small beach community was occupied by Aboriginal families who were forcibly
removed from the then Yarrabah Mission. It is an area of significance to Aboriginal people and the
site of shell middens is now buried beneath sand deposits;
Koombal Park - this beach, adjacent to Bessie Point, has several painting sites known to local
Aboriginal people and there are believed to be nearby caves that may have been frequented for
shelter in the past; and
the False Cape area - the Cape is the focal point of a mythological narration relating to the creation
of the headland and surrounding mountain range. There is also a rock painting, depicting a whale,
which has been concealed by sand drifts.
Environment North (2005) summarised a report by Cribb and Lee Long (1995) that developed a predictive
model of sites least and most likely to contain archaeological material. Least likely sites included coastal
mangroves, inland mangroves, salt pans, and urban/developed areas. Most likely sites included sand ridges
and Melaleuca open forest.
3.14. Social Values
The Port of Cairns is a multi-purpose regional port that caters to a diverse range of customers operating across tourism, bulk and general cargo, project cargo, cruise shipping, fishing and reef passenger ferries. The Port's bulk cargo includes petroleum products, sugar, fertiliser, and liquid petroleum gas. The Port has long been the natural consolidation and redistribution centre for supplies shipped to the coastal communities north of Cairns as well as the Torres Strait Islands and the Gulf of Carpentaria. The Port is one of Australia's busiest cruising destinations, operating through the Cairns Cruise Liner Terminal. The Port also includes the 261-berth Cairns Marlin Marina and the Reef Fleet Terminal which are considered the gateway to the Great Barrier Reef.
The Port owns a wide range of waterfront tourism, commercial and residential property, is home to one of
Australia's largest fishing fleets and offers extensive ship-building, and repair services with a number of
slipways and dry docks of up to 3,000 tonne capacity.
2. Community needs. Cairns and the region has a large tourism and ship industry sector as well as the Naval base. The Port of
Cairns lies right next to the CBD and is a facilitator for tourism, social and economic opportunities.
3.15. Economic Values
The Far North Queensland Regional Plan 2009 applies to the Port and acknowledges the Port’s mixed functions and economic role, including logistics and cargo handling, land-based marine activities and commercial fishing. The port is considered an ideal export hub for targeted, medium-sized, bulk exports into the future.
The Port exports raw sugar and molasses from the Mulgrave, Tablelands, and Mossman sugar growing
districts. It comprises onshore sugar and molasses handling and storage facilities and a single sugar loader
and associated wharf located within a sheltered natural bay. With its strategic location in Far North
Queensland and its protected location, the Port creates an ideal haven for pleasure craft. It also affords
cyclone contingency anchorages around Admiralty Island for small ships. The port serves as a distribution
base for vessels servicing the many small communities in the gulf region and for mining ventures in Papua
New Guinea.
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Imports to the Port include fuel, fertilisers and project cargo, whilst the HMAS Cairns Navy Base is a key
regional strategic defence asset. The Port also includes break bulk cargo handling facilities for coastal barge
supply to the adjacent Great Barrier Reef Islands, Torres Strait and PNG-Indonesia, with some capacity to
expand into new cargo handling consistent with the Land Use Strategy and long-term plans for growth of
the City and port to facilitate regional trade and development opportunities.
Economic analyses (Based on the report Economic Impact 2013/14 by Cummings Economics on behalf of
Ports North.) indicates that the Port directly contributes $838 million to the regional economy from impacts
of port related industries, a direct impact of Port-dependent industries of $288 million, and flow-on and
total impact benefits of $1,126 million (Gross Value Added $888m). Key industries that rely upon the Port
are sugar and molasses, and the domestic and international tourism sector.
Total trade through Cairns in recent FY’s sits around 1.35 million tonnes. Around 700 cargo vessels visit the
Port of Cairns each year, with greater than 50 cruise ship visits in to Cairns each year.
Table 7 Port of Cairns trade statistics FY14 to FY18
Cairns
Financial Year 2013-14 2014-15 2015-16 2016-17 2017-18 Variance
Amount %
Export tonnes
General Cargo 196,476 164,361 167,733 322,863 277,774 -45,089 -14.0%
Molasses 57,331 84,616 78,036 86,688 76,465 -10,223 -11.8%
Petroleum Products 12,354 12,119 11,338 12,232 11,371 -861 -7.0%
Sugar 170,717 389,872 290,067 304,911 205,350 -99,561 -32.7%
Total exports 436,878 650,968 547,174 726,694 570,960 -155,734 -21.4%
Import tonnes
Crude Fertilisers 32,746 49,483 34,682 37,046 58,474 21,428 57.8%
General Cargo 36,514 53,891 50,502 90,799 342,478 251,679 277.2%
Liquefied Petroleum Gas 15,912 15,280 16,248 16,198 24,854 8,656 53.4%
Petroleum Products 520,798 539,215 501,372 488,922 463,353 -25,569 -5.2%
Total imports 605,970 657,869 602,804 632,965 889,159 256,194 40.5%
Total throughput 1,042,848 1,308,837 1,149,978 1,359,659 1,460,119 100,460 7.4%
3.16. Historical Significance
Places of contemporary importance included not only hunting, fishing and gathering zones but also living spaces where people carried out their everyday activities. The traditional, historical and contemporary significance of raised sand ridges and cheniers within mangrove systems is also emphasised from a number of sites which were identified on the western side of the Inlet, within the present International Airport (Bird and Hatte 1995, as reported in Environment North 2005). These sites show occupation extending probably from pre-contact times through to the very recent past. These were primarily places from where the marine resources of the mangroves and the bay were exploited.
From a European point of view, the key cultural features of Trinity Inlet are:
• its connection with the early beche-de-mer fishery in Far North Queensland;
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• its role as one of the most important ‘gateways’ for European settlement of Far North Queensland;
and
• its role as a defence base during World War II.
These historical connections provide important links with the past and are worthy of recognition. Historical
research is continuing to record and recommend protection of some important sites, including the gun
emplacements at False Cape.
There are still relics of wartime occupation by United States and other Allied troops which may be of
interest to visitors from that country. One such feature of considerable interest is the ‘Catalina’ memorial
on the Esplanade near Upward Street. The memorial is located on the site of a debriefing hut which was
used by aircrew of flying boats based in Cairns during the WWII.
The Cairns Wharf complex is listed on the State Heritage Register. The complex is of importance in
demonstrating the evolution of Queensland's history as it represents an important stage of development of
Queensland and Australian wharf facilities dating from 1909 to 1942. The wharves are among the earliest
Australian attempts to introduce the medium of reinforced concrete into wharf construction.
3.17. Potential Impacts to Sensitive Areas or Values
The dominant sensitive environmental areas adjacent to the wharves are fringing mangroves, the seagrass meadows, and intertidal mudflats. Extensive noise sensitive residential developments are minimal and absent from the immediate adjacent area, with commercial port-related land use development the dominant land use adjacent to the port operation area at Cairns.
Foreshore intertidal mudflats and surrounding coastal wetlands are host to numerous species of resident
and migratory wading birds, many with international conservation significance. Extensive areas of
remanent marine and terrestrial vegetation surround the Port and are generally intact or close to natural
condition.
4. Consultation and Key Issues
Through existing forums, Ports North will undertake stakeholder engagement and seek public comment and submissions on this Plan. It will be provided via the Ports North website, and further refinements of this Plan will continue during 2019 (and beyond) as external feedback from stakeholders is gathered. This section and relevant other portions will be updated and subsequent versions provided on the site, along with a summary of changes. The process of stakeholder consultation and review is described further, along with details of existing and future identification of affected stakeholders.
4.1. Identification of Interested and Affected Parties
Through engagement with Port users and the community for a range of purposes over recent years (such as land use plan consultation, demand studies, new trade start up and response to issues) the following entities are identified as having potential interests in present and future port maintenance activities:
Table 8 Stakeholders
Cairns Regional Council Dept. of Defence
Cairns Chamber of Commerce
Coast Guard Incitec Pivot Tourism Tropical North Queensland
Recreational Fishing sector Cruise Companies: Sugar and Molasses Industry
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e.g. Carnival, P&O, Coral Expeditions
(e.g. QSL, MSF)
Commercial Fishing Industry
Slipway Operators: Norship, BSE Cairns Slipway, Tropical Reef Shipyard
Fuel Companies (BP, Viva, Caltex, ATOM)
Non-Government Organisations: - World Wildlife Foundation (WWF) - Australian Marine Conservation Society (AMCS)
Traditional Owners- Native Title Parties including the Gimuy, Yindinji, and Mandingilbay-Yindinji
Cairns Port Development Inc
Cairns and Far North Environment centre (CAFNEC)
Cairns Port Advisory Group
Cairns Local Marine Advisory Committee
Wet Tropics Healthy Waterways Partnership
Details of some of these key parties are provided and expanded on further below, in the context of their
interest in aspects of maintenance dredging.
A number of the above parties have a standing invite to one or more of the groups noted below. Ports
North proactively invites a range of stakeholders from such entities when items of potential relevance are
to be discussed at meetings. Additionally, Ports North’s participation in regional bodies such as the Wet
Tropics Healthy Waterways Partnership and other forums provides opportunities for broader community
involvement. Therefore, there are strong and well-established relationships and linkages between Ports
North’s stakeholder network for the regular dialogue, updates, and mechanisms for consultation in respect
of matters pertaining to maintenance dredging, both technically (through the TACC), and also formerly
(through the PAG or LMAC, etc).
4.2. Port Advisory Group (PAG)
The key consultation forum in respect of the general port activities, operations, maintenance and development, including maintenance dredging activities, is via the Port Advisory Group (PAG) which is understood to have been established in the mid-1990s, and recently had its 165th meeting. These are held roughly quarterly and have a broad cross section of potential attendees which includes around 40 regular invitees. Potential invitee organisations are described below. The PAG has been consulted (most recently November 2018) in regard to the development of this Plan and how it integrates with the broader setting of the Reef 2050 Long term Sustainability Plan and the Queensland Maintenance Dredging Strategy.
Key outcomes of the consultation with the Group on LTMP’s and the LMDMP process have included:
- Support for the ongoing maintenance of the Port
- Recognition of the need to maintain safe and efficient shipping access to the Port
- Interest in the timing and extent of dredging activities
- Status of surrounding environmental attributes (especially seagrass condition)
- Minimal interest to provide input to development of the LMDMP and involvement in future review
stages, with a “remain informed” sentiment prevailing.
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4.3. Local Marine Advisory Committee (LMAC)
The Cairns Local Marine Advisory Committee (LMAC) covers Buchan Point in the north (Cairns Regional Council) to Flying Fish Point in the south (Cassowary Coast Regional Council) and includes the Cairns northern beach suburbs, Gordonvale and Babinda.
The Committee presently has 24 members across 15 different areas of interest/representation, with
members engaged for a three-year term and meeting on a bi-monthly basis. A number of the members
have been on the committee for 10 or more years and are well informed on local ports and shipping
matters, including maintenance dredging activities at the Port.
4.4. Technical Advisory Consultative Committee (TACC)
Oversight and input on management of dredging and placement is required with the approach outlined under the NAGD (CoA 2009). This guidance sets out the development of a Technical Advisory and Consultative Committee (TACC) as a necessary component to assist in the consultation process required for a Sea Dumping Permit application. The NAGD states that:
“The TACC is intended to assist ports and other proponents and Determining Authority to access local
knowledge and reconcile various stakeholder interests.”
The TACC is intended to:
provide continuity of direction and effort in protecting the local environment
support communication between stakeholders
assist in the establishment of longer term management arrangements, including reviewing the
development and implementation of management plans and monitoring programs
review dredging and dumping activities in accordance forecast plans and programs
make recommendations to the port authority and regulators as necessary or appropriate.
A Technical Advisory Committee was initially established during the consultation phase on the channel
widening campaign in 1990, and again in 2004 to review and inform the existing LTMP and existing permit
process. The existing TACC has met annually, usually at the time of the main campaign in the Port by the
Brisbane. During 2006, the representative from the Cairns Port Advisory Group was selected as Chairperson
to facilitate the function of the group.
With the forthcoming application for a Sea Dumping Permit for the term post-2020, the role of the present
TACC will be of high importance in facilitating evaluation of the monitoring and management effectiveness,
and conveying that through to outcomes, which will inform the next management plan term in support of
the permit application. Areas raised in past consultation with that group will be topical to that process.
Consultation with the TACC shall occur during the design phase of such permit application phase,
particularly where hopper dredging and at-sea placement is proposed, and where the presence of high
environmental values prevail. This ensures high quality technical input from those representatives and gives
regulators confidence that a broad cross-section of review and endorsement occurs.
The TACC should therefore continue to be the primary mechanism, and be consulted on:
proposed program specifics such as the location of dredging and disposal sites and the timing and
duration of dredging and associated activities;
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results of the risk assessment of potential impacts to values and proposed mitigation and
management controls; and
scope of program monitoring and reporting requirements.
Membership organisations include those presently involved in the existing TACC for the Port, namely
GBRMPA, Ports North, state and local government, industry associations, traditional owners, and
community interest groups.
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Table 9 Cairns TACC Membership
Organization Represented Stakeholder Interest
Department of Environment and Science (DES) State Government assessment and regulation or Port activities under the Coastal Protection and Management Act 1995 and the Environment Protection Act 1994
TropWATER – Tropical Water & Aquatic Ecosystem Research, James Cook University (JCU)
Research, Seagrass Habitats
Local Marine Advisory Committee (LMAC) Great Barrier Reef Marine Park management issues at a local level and sports fishing
Department of Agriculture and Fisheries (DAF) State Government assessment and regulation of Port activities under the Fisheries Act 1994
Maritime Safety Queensland (MSQ) Regional Harbour Master, shipping, coordination, emergency response
Cairns Regional Council (CRC) Local Government, community, local environmental committee
Department of the Environment and Energy (DoEE) Assessment and Regulation of Port activities under the Environment Protection (Sea Dumping) Act 1981 and the Environment Protection Biodiversity Conservation Act 1999
Great Barrier Reef Marine Park Authority (GBRMPA) Great Barrier Reef Marine Park management. Assessment and regulation under the Marine Parks Act 2004
North Queensland Land Council Contact point for Native Title Claim groups relevant to Cairns area
Cairns and Far North Environment Centre Conservation
The TACC has operated without a Terms of Reference (ToR), however, operates within the objectives of the
NAGD requirements, and it is envisaged that these arrangements will be formalised in the preparations for
the next permit term. A meeting of the Committee is facilitated by Ports North on an annual basis, typically
in August and around the time of the annual channel maintenance. The Group meets to participate in a
review of the monitoring outcomes, any compliance reporting and is updated via email or letters on an as-
need basis between meetings.
As described within the NAGD (CoA, 2009), the TACC is intended to have a scope to:
provide continuity of direction and effort in protecting the local environment;
aid communication between stakeholders and provide a forum where points of view can be discussed and conflicts resolved;
assist in the establishment, as appropriate, of longer term permitting arrangements, including reviewing the development and implementation of Sampling and Analysis Plans, Long-Term Management Plans and research and monitoring programs;
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review ongoing management of dredging and dumping activities in accordance with these Guidelines and permitting arrangements; and
make recommendations to the proponent and the determining authority as necessary or appropriate.
TACC meetings are held annually, around the time of the major dredging component, which has typically
occurred around August.
Outcomes of the consultation with the TACC meetings convened since 2004 have focused on:
Understanding of the annual SAP and Seagrass monitoring results;
A specific TACC meeting on 9 March 2010 to discuss the draft LTMP and seek comments from
stakeholders. Comments received have been considered in preparation of this LTMP.
One particular outcome from the meeting was to identify suitable candidates to represent
recreational and commercial fishing stakeholder interests on the TACC. This was actioned in 2010,
with the inclusion of a representative from the LMAC, which has both recreational and commercial
fishing representatives. The LMAC representative or Ports North Environment Manager can convey
any matters of interest between the two groups.
Amendments to the Sea Dumping and Marine Parks Permit in 2014 and 2016 to address permit
volume units and the request to address the units of measure for volume calculations utilised in the
initial application.
Updates on the progress of each monitoring program’s component have been provided on an annual basis
to the TACC, and the outcomes reviewed. To date no changes to the program have been required, and the
current Long-term Monitoring Schedule (Section 7.10) of the LTDSDMP 2010-2020 prevails.
Overall, this consultation process has been of a relatively general neutral outcome with no specific major
ongoing issues raised by stakeholders or dominating the agenda. There are no major issues identified or
outstanding issues of contention for the Cairns TACC.
4.5. Future Consultation
The existing consultation processes and stakeholders associated with the above three groups are considered appropriate for stakeholder input into the future management of Port operations.
Consultation to date has not raised any significant issues and the number of key items requiring future
consultation has been relatively minor. No requests for significant modification of management practices or
monitoring programs have been tabled or identified over the past 10 years.
All such future consultation will be via the established TACC, consistent with the approach outlined under
the NAGD.
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5. Sediment Assessment
Outlined in this section is a description of the nature of the sediment and how it interacts with Port operations in the past, present and future. This demonstrates a thorough understanding of regional and local processes, understanding of properties (physical, chemical and biological) and informs the subsequent sections on the justification and proposed sediment management solutions.
5.1. Port Sediment
The understanding of port sediment quality is well known through various studies since around 1994, and has informed the development of past Management Plans at the Port of Cairns. A summary of the status of sediment characteristics is included at Section 4.0 of the LTDSDMP 2010-2020. The Sediment Analysis Plan (SAP) process is overseen by GBRMPA on an annual basis. A SAPlan is developed by Ports North’s consultants, lodged with GBRMPA to seek endorsement for implementation, and then once the fieldwork and analysis and reporting is complete, a SAP Report on findings is logged to seek approval to proceed to dredge the respective dredge areas.
5.1.1. Physical Properties
The physical sediment analysis and field observations confirmed that the grain size composition of the sediments varies between each of the respective dredge areas, although all areas have a very high portion silty clays. The main channel is dominated by the finer clay and silt fractions and some minor sand areas, where as the marina and berth areas are predominantly fine silty clays due to their low energy depositional hydrodynamics. There is a distinct change once the horizontal profile reaches the underlying stiffer clays, which are of a generally light grey to medium orange mottled clay bedrock or terrigionus layer.
These observations are consistent with the estuarine hydrodynamics of the broader nearshore
environment of Trinity Bay. Finer material is more likely to accumulate in the mid channel, whilst the hard
seabed in inner port and swing basins is subject to higher tidal velocities, which reduce the potential for
fine material to accumulate. The outer channel is subject to wind driven currents, and northerly sediment
migrations as part of the long shore drift, which results in increased sediment deposition on the seabed of
the outer channel.
5.1.2. Chemical Properties
The suitability of the maintenance dredging material has been conducted through the annual SAP process, based on the NAGD framework. This enables conclusion to be drawn on whether maintenance material is suitable for unconfined sea disposal.
The sediments subject to maintenance dredging in the main channels are not considered contaminated
and have been assessed and approved by the GBRMPA as suitable for unconfined sea disposal each year
since at least the mid-1990s. This assertion is based on the absence of material that exceeds the NADG
screening level triggers, local agreed limits, or permit conditions.
5.1.3. Introduced Marine Pests
The most recent Introduced Marine Pest (IMP) survey was conducted in 2018 as part of the annual SAP process. No known pest species were located. IMP species from the National Introduced Marine Pest Information System (NIMPIS) QLD target pest species list have in the past been detected within Trinity Inlet, including:
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Caribbean tubeworm (Hydroides sanctaecrucis)
Asian Bag Mussel (Musculista senhousia)
Asian Green Mussel (Perna viridis)
The identified IMP species have been previously recognised as having been translocated to Australia as
biofouling on ships’ hulls or through ballast water discharge.
Actions to eradicate, or limit the distribution of the above species, specifically the mussels, have been
enacted by DAWR (Quarantine) and QLD Biosecurity during past incursions.
These detections highlight the vulnerability of the Port to potential marine pest incursions, and considering
the continued high volume of international and recreational vessel traffic through the Port, periodic
monitoring for IMP is warranted. This is addressed in the annual SAP and routine post sampling, as set out
in Section 7.10 of the Long-term Monitoring Plan.
A number of the above properties continue to confirm that the sediments of the Port have physical,
chemical, and biological properties that are of low concern (compared to locations with highly
contaminated sediments) and essentially makes them good for a range of dredging options and placement
options, including keeping them within the local marine system, and ocean placement.
5.1.4. Potential Contamination Sources
The types of local industries and the concentration of urban and city settlement adjacent to the Port catchment (Section 2.1) provide an insight into the types of contaminants that may have entered the waterways and sediments of the Port over time. The uncontaminated nature of the sediments is therefore encouraging considering the concentration of human influences immediately adjacent to the port sediment catchment.
Based on previous SAP studies, potential contaminants of concern include:
Metals and metalloids;
Organotin compounds (tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT)).
Contaminant concentrations found in estuarine sediments are controlled by a range of processes including
anthropogenic inputs. Sediment grain size, which itself is a function of hydrodynamic processes (currents,
waves) is also a primary determinant of contaminant concentrations and potential ecotoxicity. Due to their
physical and chemical characteristics, fine- grained sediments tend to adsorb contaminants, and areas
containing a high proportion of sediments in this size range can have higher contaminant concentrations
(particularly metals/metalloids) than areas dominated by coarser grain sediments. Fine sediments such as
clay can also chelate contaminants, making them less biologically available. A wide range of physico-
chemical sediment properties and biological processes (e.g. bioturbation by burrowing organisms) also
strongly influence contaminant concentrations. The natural geology occasionally has high concentrations
of arsenic which have been regularly found in several studies of the Trinity Bay area.
The individual contaminant inputs from various sources to the Trinity Bay catchment have the potential to
cause cumulative sediment quality and water quality issues. These issues may in turn have an impact on the
ability to undertake and manage maintenance dredging. To understand these potential impacts in relation
to maintenance dredging activities the following monitoring programs are required:
Ambient water quality and sediment quality monitoring
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Activity targeted water quality and sediment quality monitoring
Ambient ecological monitoring
More information about the related monitoring programs is provided in Section 7.10 of the LTDSDMP 2010-
2020. While the Port has a limited ability to prevent contamination from many of the potential sources, the
Port takes appropriate steps to prevent or minimise contamination through:
Monitoring and management of port activities under the EMS (Section 1.2): internal and external
audits; environmental training and awareness; the development of EMPs for projects and
operations; environmental licenses and approvals; adherence to approval conditions and
legislative requirements;
Environmental Awareness for all staff, Contractors and Port Land Users;
Monitoring of compliance and ambient monitoring programs;
Port planning: planning future port and port-related development; reviewing and commenting on
Environmental Impact Studies for proposed development which will utilise the Port; fulfilling a
legislative assessment role for developments on or adjoining Strategic Port Land under the Planning
Act 2016; management of activities undertaken on Strategic Port Land and at port facilities (e.g.
restricting high risk activities including ship hull cleaning); supporting the development and
implementation of land use plan.
5.1.5. Sediment Movement and Coastal Process within Trinity Bay
The Port of Cairns is subject to a high ambient load of fine sediments, and has, since its very first establishment, required regular maintenance dredging. Even though the Port is located adjacent to the mouth of the Barron River, and the catchment is subject of intensive agriculture and cropping with associated wet tropics sediment loss issues, the net sedimentation within the port infrastructure has not varied significantly in recent years.
Trinity Bay is a naturally high turbidity environment. Longshore currents and adjacent river supply large
volumes of sediment annually and wind and wave driven re-suspension also lifts large volumes of sediment
into the water column during moderate to severe weather. This is illustrated in Figure 13 to 14.
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Figure 12 Concept Model of Coastal Processes in Trinity Bay (Environment North, 2005)
Figure 13 Concept Schematic of Sedimentation Processes in Trinity Bay (Carter, et al 2002)
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Figure 14 Sedimentation Processes in Trinity Bay (BMT WBM 2016)
On a smaller scale, run-out tides also draw turbid plumes off adjacent mud banks and carry these into the
channel area.
Reef 2050 (CoA, 2015) identifies nine actions relating to the theme of “reducing the impact of ports and
dredging”. The Queensland Ports Association (QPA) was tasked with driving the ports sector’s participation
and input into marine science, environmental governance and port policy development and
implementation. The QPA delivered the outcomes for WQA17, where the objective of WQA17 was to:
Understand the port sediment characteristics and risks at the four major ports and how they interact and
contribute to broader catchment contributions within the World Heritage Area.
Outcomes of the WQA17, including the schematic and quantum of volumes prevailing for maintenance
dredging, correlates with the long-term trend of maintenance dredge requirements and is summarised in
Figure 15 and Error! Reference source not found.
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Figure 15 Sediment Budget for Cairns- from WQA17 Report (BMT, 2018)
Table 10 Relative Sediment volume for Port of Cairns from WQA17 Report, (BMT, 2018)
From this contemporary work (BMT, 2018), it can be noted that the ambient sediment processes, and the
relative quantum of material disturbed by maintenance dredging will continue to be a driver for
maintenance dredging due to the large volumes of mobile sediment along the GBR coast.
5.2. Minimisation of Sediment Accumulation and Dredging Need
As noted in prior sections, the ambient sedimentary regime for Trinity Bay is dominated by the natural
occurrence of a high sediment load. Hence the ability to influence the accumulation within the Port
channels and berths is minimal, and the need for intervention will need to continue in the form of
maintenance dredging.
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Minimisation of maintenance dredging has been enacted via the complementary use of bed levelling for a
number of years, especially for the inner port and marina areas. A combination of grab dredging the
entrance and fairway sections occurs first, followed by bed levelling of the marina berths. In more recent
years, bed levelling has been used for portions of the entrance channel and the swing basins, due to
availability of the Pacific Conquest. This process moves the deposited material to a natural deep hole in the
channel or swing basins. Evidence to date indicates this practice has been a successful alternative to
maintenance dredging under certain conditions, both in cost-effectiveness, and in having minimal
environmental impacts due to the short term of operations (typically less than a week of disturbance).
Beyond the use of bed levelling, alternatives (including those used at overseas ports such as sediment
bypassing, side casting and interception structures) to dredging are very limited, and have not been subject
to detailed design or feasibility assessment.
From evaluation of the information in the following sections, it is clear sedimentology of Trinity Bay is well
understood and managed in an optimal way under existing regulation and policy. Consideration of options
to minimise the need for dredging is to remain one of the ongoing improvement actions of this and future
plans.
5.3. Maintenance Dredging and Disposal Requirement
Loss of depth within the channels due to siltation has a significant impact on the draft of vessels that are able to transit and navigate efficiently and safely within the Port. Depths reductions of up to 1.5m are recorded from year to year in portions of the Channel, and a summary of past, present and future dredging requirements are set out in the following sections. There has been, and will remain, an ongoing requirement to undertake maintenance dredging and sea disposal for the Port of Cairns.
The Sea Dumping and Marine Parks Permit accommodate the dredging forecast, which is to continue over
the term of this LMDMP. It is to be the subject of significant further forecast and scenario planning, and
informed by the progress of the CSDP and maintenance outcomes once that channel profile is established.
This will be reflected in the permit volume subject of the permit term post-2020.
5.3.1. Past Maintenance Dredging
A summary of past dredging activity is presented below to place in context a number of facets of the Cairns area and justifies the present, and potential future, disposal requirements.
The Channel has been developed since the late 1890s, through a series of
campaigns to recover sands for land-based reclamation for portions of the CBD and
industrial areas (Portsmith) of the city over an extended period. An example of that
activity is shown in Error! Reference source not found..
Past
Present
Future
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Figure 16 TSHD Sir Thomas Hiley - pumping sand to shore near the present Wharf Street
As a naturally sediment laden and accreting tropical embayment, the need for major capital and maintenance
works has been required throughout the Port’s history. Past Harbours and Marine and TMR survey drawings
show the presence of an established marked entrance channel and allocation of areas as offshore spoil
grounds.
The Port has been subject to annual dredging activity since the early 1900s.
Capital dredging was last undertaken in the early 1990s to generally widen the channel from 76m to 90m.
This was done by cutting 7m each side into adjacent banks and placing the material in a sea disposal site.
There is anecdotal evidence of some significant additional maintenance dredging in the subsequent years as
the channel profile and annual sedimentary regime established. Maintenance of that profile has continued
since.
Maintenance dredging is carried out in the outer channel (generally between chainages 14,500m and
24,200m) annually by the THSD Brisbane since its maiden campaign voyage in 2001. Prior to that, the TSHD
Sir Thomas Hiley was used for the three decades. The Brisbane has typically been engaged for four weeks
annually. Some years have involved maintenance dredging of the berth pockets and Crystal Swing Basin.
5.3.2. Present Maintenance Dredging
The present annual dredging requirement for the Port is consistent with the annual permit limit of up to
350,000 dry tonnes – with about 320,000 dry tones removed from the channel, and about 30,000 dry tonnes
removed in the inner port. The present volume is made up of maintenance dredging material from the main
navigation channels (Figure 4). These are maintained to the declared depths shown in Error! Reference
source not found., and have an approximate length of 12km. The entire Port is not dredged during each
campaign, with maintenance dredging expected to occur over only 60% of the channel area. Isolated parts
of the channels, outer channel towlines, berth quay lines, and swing basins are where the majority of siltation
occurs.
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A contingency is include within the permit volume, and makes provision for emergency or unforeseen events
such as extreme weather during the permit period or additional siltation in some channels. The permit
volume does not account for any additional maintenance dredging requirements due to the completion of
capital works during this period, and either a permit variation or new approval would be required.
The Sea Dumping and Marine Park Permit outlines an annual limit of an accumulated annual volume of
350,000 dry solid tonnes from the campaign of works undertaken using the Willunga and Brisbane, which is
the forecast maximum average campaign, and upon which impact assessment for the LTSDSMP 2010-2020,
and also this LMDMP is based (Section 9).
Maintenance dredging has occurred annually since 1990. Actual campaign volumes over the present permit
period, as required under the IMO Annual Report Form condition of the Marine Park Permit, are presented
in Table 11 (*figures for 2018 accurate to July 2018).From 2014, reporting in all three units of measure was
required, and some values are based on conversion factors (i.e. inner port Willunga activity for in-situ and
dry tonnes), as provided in the return forms and supporting information provided to the GBRMPA. Annual
pre maintenance dredging surveys regularly show sediment accumulation, and tend to show greater siltation
in the first half of the year following the wet season.
Table 11 Dredging and Placement Volumes over the Present Permit Period
TSHD Brisbane Willunga Totals
Campaign In-situ cu.m.
Wet cu.m.
Dry Tonnes
In-situ cu.m.
Wet cu.m.
Dry Tonnes
In-situ cu.m.
Wet cu.m.
Dry Tonnes
2010 708,923 177,505 34,505 24,155 743,428 201,659
2011 736,631 205,990 46,900 32,830 783,531 238,820
2012 719,220 57,955 777,175
2013 866,894 61,305 928,199
2014 531,953 822,225 336,795 42,494 47,570 39,239 574,447 869,795 376,034
2015 497,678 946,211 316,910 36,880 41,309 31,692 534,558 987,520 348,602
2016 416,559 804,726 306,801 35,593 39,865 32,411 452,152 844,591 339,212
2017 358,095 779,414 258,482 33,500 37,520 28,743 391,595 816,934 287,225
2018 391,263* 834,503 321,497 10,792 4,355 9,364 402,055 838,858 330,861
Totals 2,195,548* 7,218,747 1,923,980 159,259 371,284 198,434 2,354,807* 7,590,031 2,122,413
5.3.2.1. Annual Siltation Trend
Ports North’s in-house Hydrographic Surveyor has kept comprehensive survey records and volume analyses
of siltation over the various segments of the channel for the past 18 years. These have been used to establish
and update a range of insurance depths over the length of the channel which varies from 0.3m to 1.7m. The
long-term average siltation records indicate approximately 40,000 in-situ cubic metres of siltation falls into
the channel between chainages 14,500m and 24,200m monthly.
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The outer channel is dredged to a series of target depths as illustrated in Error! Reference source not
found.7. These have been established based on siltation assessments as described further below.
Figure 17 Channel Target depths required to address siltation
Inner harbour dredging is undertaken annually by Ports North using its grab dredge and two spilt hopper barges of 300 cubic metre and 370 cubic metre capacity respectively. This occurs in the berth pockets, Marlin Marina, Navy and fishing basins throughout the Port.
Very little historical dredging has been required in the inner channel as this was of naturally sufficient depths and remains self-clearing.
Evaluation of dredging and disposal requirements should be informed by a thorough understanding of what
has been required in the past to ensure that maintenance responds to the prevailing hydrodynamic and
sedimentary processes. The aspects of this are outlined below and provide detail on the basis upon which
the requirement for and justification of maintenance dredging and disposal is made.
5.3.2.2. Material Placement Area – Ocean Disposal Site
All maintenance dredging material from the navigational channels has been placed at the Dredge Material
Placement Area. Such use is forecast to continue for at least the balance of the present Permit term, subject
to the review and continual improvement processes detailed in Section 1.5 and the outcomes of the
assessment for the next Marine Parks and Sea Dumping permit beyond 2020. Figure 3 illustrates the location
of the DMPA in relation to the dredge footprint. The closest boundaries of the site are 10km from the
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mainland and 10 km from the coral reefs to the north of Green Island. The depth of the sea disposal site
ranges from 9m to 15m, with an average of 13m below datum. It is calculated that capacity remains over
three quarters of the site for a number of years, before it would attain the height where it may impinge on
vessel navigation. Regular bathymetric surveys of the site, including a post-dredge in late 2018, confirm the
site is still functioning well.
Approval of the present DMPA was obtained around the time of the 1990 capital dredging under Section 86
of the Queensland Harbours Act 1955. Since that time the DMPA has been approved for use multiple times
for maintenance dredging requirements of the Port, and one minor capital volume (75,000 cu.m) from the
City Port North – Marlin Marina dredging. The balance of material placed at the site has been from
maintenance of the Port since 1990, and is subject to ongoing assessment as per the prior long-term
management plans and supervision by the TACC. It is considered to have performed as an optimal placement
site over past years. As part of the placement options assessment of the Cairns Shipping Development
Project, evaluation of the site and possible adjacent areas was made under the Environmental Impact
Assessment for the placement of 4.4M cu.m. of material, and this process identified an alternate site slightly
east and in deeper water. This site will be a consideration for nomination for the next marine park and sea
dumping permit assessment, or included as an alternative future location once the present site is is
considered full. This is subject to assessment by the Regional Harbour Master in terms of influence on vessel
navigation.
Future evaluation of placement site use and management is to be considered in the preparation for the next
permit term, and reflected in future updates to this LMDMP.
5.3.2.3. TSHD Brisbane
The TSHD Brisbane was built in Cairns in 2000, specifically designed for the maintenance dredging of QLD
ports. It has been the equipment of choice for QLD ports since it was commissioned in 2000 (Haskoning
Australia Pty Ltd 2016). Whilst it is noted that future maintenance dredging could be undertaken by other
TSHDs with similar equipment features, the maintenance
of the Port of Cairns main navigational channels has been
undertaken by the TSHD Brisbane since 2000 and as such,
impact assessment and management measures for
maintenance dredging presented in this LMDMP are
primarily focused on this vessel.
Figure 18 TSHD Brisbane
TSHDs have typically undertaken the majority of the maintenance dredging at QLD Ports as they are the
most suitable type of dredger. They have high production rates, can operate in offshore areas and heavily
trafficked areas, have a hopper allowing offshore placement, and are well suited to dredging soft
unconsolidated sediment typically associated with maintenance material (Haskoning Australia Pty Ltd
2016).
The TSHD Brisbane was designed with mechanisms to mitigate the environmental impacts caused by the
dredging operations. These mechanisms are equivalent to the features installed in the latest TSHD models
used around the world. Since its commissioning it has been updated regularly to incorporate the latest
environmental advances in dredging technology, ensuring the TSHD Brisbane operates at the same level as
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the most recently built TSHDs (Haskoning Australia Pty Ltd 2016). The environmental impact mitigation
features are described below:
Central weir discharge system (green valve or anti-turbidity function): this system works by
controlling discharge from the dredger to limit the turbidity of overflow
waters entering the receiving environment. The TSHD Brisbane has five
equally spaced conical valves in the floor of the hopper which when opened,
release the material. The middle valve (DV3) is surrounded by a set of six
cylindrical rings stacked on top of each other to form a weir of adjustable
height. When dredging light material such as silts, only the top ring is lifted to
create the largest possible hopper capacity and settling time for the material.
When the hopper reaches the point of overflow, DV3 is partially opened to
allow excess water to escape. The aperture of DV3 is regulated to maintain a
water column within the circular weir stack and thereby minimise the
entrapment of air in the overflow water. This reduces the amount of air
bubbles which can act to carry material to the water surface and generate
excessive plumes.
Figure 19 TSHD Brisbane Overflow valve
Below keel discharge point: the discharge of sediment from the hopper occurs at keel level in order
to prevent unnecessary turbidity and dispersal of fine sediments.
Turtle deflection devices: a flexible chain deflector is attached to the dragheads to prevent the
entrainment of sea turtles during dredging operations. The device design has been evolving for the
past 20 years and its efficiency confirmed by several research projects.
Low wash hull design: by minimizing the size of wash waves created by the vessel movement, the
low wash hull design reduces agitation on the water surface, minimising the interference with the
sediments suspended in the water column during discharge. This design can also reduce fuel
consumption and damage to riverbank environments.
Electronic positioning system: the TSHD Brisbane is equipped with a global positioning system which
is used during the operations. The positioning data is used during the discharge operations to
identify the beginning and end of the material placement locations and provide evidence to the
regulators to ensure compliance with the material placement boundaries. The GPS data also assists
the contractor and clients to identify the areas of origin of the sediment for each cycle.
EMP: PBPL maintain a Dredge Management Plan which addresses standard operational procedures
to minimise environmental impact. Separate EMPs are also developed by PBPL for each specific
port/project where it undertakes dredge works. This EMP addresses matters specific to the project
including local regulations, sensitivities, and specific permit conditions. It is submitted for review
and approval by each port prior to commencement of the work.
In accordance with Principal 10 of the MDS, any other TSHDs undertaking maintenance dredging works in
the future at the ports within the GBRWHA should result in environmental performance that is equal to or
better than current equipment or methods used for navigational channel maintenance.
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5.3.2.4. Grab Dredge - Willunga
Additional to the maintenance dredging and sea disposal requirements described above, maintenance dredging outside of the main navigational channels in smaller navigational infrastructure such as the berth pockets, Navy Base, Marlin Marina and Commercial Fisherman’s Bases 1 & 2 is also required.
Dredging of these structures is
undertaken by the clam-shell dredge
Willunga due to the need for
equipment that can operate in areas of
limited manoeuvrability. The Willunga
is supported by two barges (GHT22 and
AD501) which are towed using the port
tugs, out to the placement site. This is
around a three-hour return cycle. As a
result of the dredging methodologies a
tug and barge process is required to
relocate these materials to the DMPA.
Figure 20 Grab Dredge Willunga and barge
Environmental management and monitoring is undertaken for each of these campaigns in accordance with
statutory approval processes, sea dumping and marine park permit conditions and the LTDSDMP 2010-
2020.
5.3.2.5. Bed Levelling
Use of a vessel known as a bed leveller is also enacted as a standalone activity or to complement the dredging activity by either the TSHD Brisbane or the Willunga. Such a vessel is used to move material under the seafloor to adjacent deeper areas, or to level out holes or trenches left by the actual dredging equipment.
Figure 21 Bed Levelling vessel Pacific Conquest and close up of drag bar
The vessel Pacific Conquest is also utilised for the channel, swing basin, marina and wharf berth pockets to move larger volumes of material than the Pile Frame and is purpose-built for use at QLD ports either in accompaniment to a TSHD or as a stand-alone process.
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5.3.3. Future Maintenance Dredging
From the trends in accumulation, as evidenced by the volumes required to be dredge to meet the design target depths, there is a predicted ongoing requirement to undertake maintenance dredging and sea disposal of around 350,000 dry tonnes per annum as set out for the present Sea Dumping and Marine Parks Permit. Such dredging requirement is forecast to continue over the term of this LMDMP. It will be the subject of significant further forecast and scenario planning informed by the progress of the CSDP and the maintenance outcomes once that channel profile is established. This will be reflected in the permit volume subject of the permit term post 2020.
Further to that and in accordance with Principle 5 of the MDS, an increase in channel depths will only occur
as a result of approved capital dredging following assessment of implications of future maintenance
dredging needs and disposal options through approval processes, which will in the case of Cairns, be
required to accommodate the outcomes of the CSDP. Such forecast maintenance dredging requirements
have been considered in Chapter B3 – Coastal Process of the RD-EIS and confirm a predicted 3-5% increase
in annual channel maintenance requirement, which is well within the inter-annual variability seen in past
dredging requirements. These forecast volumes will inform the application process for the next Sea
Dumping Permit and Marine Park Permit during 2019-2020 period. For the purposes of this document, a
quantum in the order of 365,000-375,000 dry tonnes per annum is proposed as forecast ongoing volume,
which allows for the increase predicted above, and will be subject to future detailed evaluation and
justification.
Evaluation of dredging and disposal requirements should be informed by a thorough understanding of what
has been required in the past to ensure that maintenance responds to the prevailing hydrodynamic and
sedimentary processes. The aspects of this are outlined in this Section 5.
The need for future maintenance dredging will be minimised through consideration of the objectives of the
1996 Protocol to the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other
Matter, 1972 (the London Protocol) and the Environment Protection (Sea Dumping) Act 1981 (the Sea
Dumping Act) which include minimising pollution caused by sea disposal.
The London Protocol requires consideration of measures to prevent, reduce, and where practical, avoid the
relocation of dredge material at sea. Ports therefore aim to reduce their maintenance dredging
requirements as much as possible and will only undertake dredging when necessary. It is also worth noting
that maintenance dredging is considered an expensive and inconvenient requirement for many ports
(Haskoning Australia Pty Ltd, 2016) and so ports strive to undertake it as efficiently as possible.
A number of strategies to minimise maintenance dredging activities could be evaluated, some of which are
listed below. If further opportunities become apparent and reduce the quantum of maintenance dredging
requirements, these will be considered as part of the continual improvement process for maintenance
dredging.
Hydrographic survey: repeat hydrographic surveys ensure that maintenance dredging is focused on
the areas where sedimentation has occurred and that maintenance dredging is only undertaken
when and where it is required.
Shipping Simulation: fine tuning the specification of vessels and sailing conditions through
computer simulation in conjunction with MSQ, Pilots and shipping companies to resolve the
parameters within which certain vessels can utilise a channel and facilities of set dimensions, may
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reduce the need for certain aspects of either maintenance quantum or frequency or future capital
works.
Under Keel Clearance: a range of present and emerging technologies may enable acceptable
navigation safety whilst utilising the present channel depth, through consideration of dynamic or
static parameters.
Bed levelling: used to level out high points in a channel
and, therefore, help to reduce the frequency of
maintenance dredging.
Tidal windows: maximising vessel movements through
shallower areas during higher stages of the tide to
ensure sufficient under keel clearance. This approach
can result in operational inefficiencies and has the
potential to result in safety and environmental
implications if not managed correctly.
Port Management: ports will typically manage their
infrastructure and operations to minimise the
requirement for future maintenance dredging including
working with port tenants and customers.
Figure 22 Placement options assessment in 1990
The unpredictable nature of extreme weather events and the resultant impacts on coastal processes at
the time or as a lag to such events, is difficult to predict. However, based on experience of the past ten
to 15 years and the extreme events that have influenced Cairns (e.g. TC Larry, and Yasi), the
maintenance dredging future requirement is likely to be close to or marginally above the present
annual requirement and prevailing permit annual and contingency quantity. The scope of future
detailed design and documentation to inform the Sea Dumping and Marine Park Permit is proposed to
include consideration of scenario analysis to ensure a robust and justifiable volume assessment to
support that assessment process.
5.4. Examination of Reuse, Recycling, and Disposal Option
Examination of reuse, recycling and disposal options for the Port of Cairns material has been the subject of four recent studies, namely:
- The studies that informed the Strategic Assessment (i.e. SKM, 2012-13),
- The QLD Maintenance Dredging Strategy, Technical Appendix (Royal Haskoning, 2016)
- Two stages of Environmental Impact Assessment (EIS for the Cairns Shipping Development
Project (2014, and 2017).
The current approvals for use of a marine DMPA have obviated the need for sediment disposal on land.
Provisions in the Sustainable Ports Development Act 2015, recognised certain existing activities and
accommodate management of sediment from maintenance dredging via at-sea placement. However,
the legislation places constraints on capital dredging projects and the material disposal options. As
outlined in Section 1.2, the approval process is the key driver for examination of disposal options,
including land-based options, and to meet the QLD MDS requirements. The next few tables also provide
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an indication of key issues likely to be involved as an initial examination, however, future requirements
to undertake detailed evaluation of consideration of placing maintenance dredging either on-shore, or
via re-use or recycling, will likely utilise an expansion on the multi-criteria assessment approach noted in
the above four studies and will be enhanced and updated with contemporary information.
A summary of the most recent works in Chapter A2 Dredge Material Placement Options, is noted as
highly relevant to this section, and the reader is directed to that source,
(www.portsnorth.com.au/csdp) as it summarises all past studies, and provides the MCA outcome,
applicable to both the project, and also the maintenance material aspect. The work is therefore quoted
as follows:
“This chapter provides an assessment of potential dredge material placement area (DMPA) options,
and has informed the scope of this EIS. Using a Multi-criteria Analysis (MCA) approach, it assesses
both marine and land dredge material placement options for the project against environmental,
social, planning, economic, and logistical criteria. Five marine and five land options were examined;
these locations were chosen based on a number of previous studies that have investigated potential
placement options - Connell Wagner (1990, 1992), Environment North (2005), Worley Parsons
(2010) and SKM (2013). The assessment concludes with the
selection of a preferred land placement site (East Trinity option)
and a preferred marine placement site (Option 1A, upon which
Parts B and C of this EIS are based). The ‘appropriateness’ of
the preferred land placement site is assessed in Chapter A3,
Appropriateness of Preferred Land Placement Site at East
Trinity in accordance with the assessment process outlined in
the National Guidelines for Dredging (2009). Part D of this EIS
provides a more detailed review of the environmental values of
the preferred land placement site. The objectives of the Sea
Dumping Act, which implements Australia’s obligations under
the 1996 Protocol to the Convention on the Prevention of
Marine Pollution by Dumping of Wastes and Other Matter,
1972 (the London Protocol) include minimising pollution caused
by ocean placement. Evaluating alternatives to ocean
placement and identifying and implementing measures to
prevent pollution are important first steps in the assessment
process. This chapter meets these objectives by providing an
assessment of alternative locations to ocean placement.
Furthermore, the National Assessment Guidelines for Dredging
2009 (NAGD) provides the framework to manage dredge
material placement, and also specifically requires the
evaluation of alternatives to marine placement.
Figure 23 Multi criteria options assessment areas 1990 to 2018
The EIS Guidelines and Terms of Reference (TOR) require options for placement of the dredge
material, both land and marine, to be assessed. A2.2 Assessment Methodology The assessment of
dredge material placement options involved the following key steps:
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Review the history of dredge material placement in Cairns to understand the basis for decisions
regarding placement options and the parameters for future placement (Section A2.3)
Review previous dredge material placement studies undertaken in Cairns – these studies
identified and assessed a range of dredge material placement options in the Cairns area
(Section A2.4)
Assess beneficial reuse options through an understanding of the dredge material characteristics
along with logistics of dredging and placement (Section A2.9)
Identification of potential land and marine dredge material placement options (Section A2.8)
Assessment of identified placement options using a MCA process to determine a preferred land
placement option and a preferred marine placement option (Section A2.9). ”
As described in the outcomes of Chapters A2 and A3 of the CSDP RD-EIS, land based placement of
dredge material from maintenance activity at the Port of Cairns, for the quality and quantity dredged on
an annual basis, remains unviable. Approval will continue to be sought to use the identified off shore
disposal sites. A range of beneficial re-use options that have been put forward for other Australian and
international ports will likely form a portion of the processes to be evaluated during the support studies
for the next permit application phase.
Consideration of placement options is made consistent with the QLD MDS and support Technical
Appendices which document the need for consideration of annual mean future maintenance dredging
volumes. These are then used to estimate the potential land area requirements for on-land processing of
this material over five-year and 10-year planning horizons. These land areas have been determined for
each port that has periodic maintenance dredging requirements. Details for Cairns are summarised in
Table 12. The indicative land area requirements are based on placement of a 1m thick layer of settled
silt/clay material with a bulking factor of 2 to 3 relative to its in- situ volume.
Table 12 Estimated requirements for land area over 5 year and 10 year planning horizons
Port
Annual Mean
(m3 / yr)
Typical Maintenance
Dredging Frequency
(years)
Indicative Land Area Requirement (ha)
5 years
10 years
Cairns 400,000 1 500 1000
It is evident from Table 12 as taken from the MDS, that Cairns has a high maintenance dredging need,
along with Gladstone and Townsville, and would require significantly large on-land receiving facilities.
When the high environmental value associated with the GBRWHA coastal area is considered, the
construction of large on-land receiving areas in close proximity to the coast would raise a wide range of
environmental issues.
In addition to the significant land areas required, the timeframe for design, documentation, approvals, and
construction of on-land disposal facilities are lengthy and costly, as evidenced by the CSDP process over
the period 2012 to 2018. This is significantly longer than the typical period of six months required to obtain
the necessary approvals for placement of maintenance dredge material within an existing sea DMPA.
These predictions and references will likely be evaluated in finer detail, along with available area
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evaluation, to support future iterations of this LMDMP as per the process outlined in Section 1.2 and will
inform future application and approvals processes.
Further to this consideration of land-based requirements, an initial relative comparison of options is
presented in Table 13 and draws from other examples of option assessments undertaken for Australian
ports where high volume of fine sediments are subject to disposal options assessment.
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Table 13 Disposal Options and Relative Assessment against Issues
Options Issues
Human Health Environment Operations Economic Legislative
No
t dred
ging
Increases risk to navigational safety and health of humans on vessels Reduces cyclone resilience
Increases greenhouse gases due to reliance on road, rail, and air transport for the movement of products, in order to continue the same level of support to the region.
Results in the depth restrictions for vessels due to infilling of the channels, and ultimate cessation of commercial vessels to the port.
Results in significant loss of revenue for the Port and region. Not dredging adversely increases the cost of living for community as access to products and fuel decreases. Not dredging has a significant direct and indirect impacts on employment (port employees, port users and customers, and companies that rely on imports/exports via the Port.
Conflict with Queensland’s Transport Infrastructure Act 1994
Installin
g sed
ime
nt b
arrier d
evices (p
erm
ane
nt
hard
structu
res), to
red
uce d
red
ge vo
lum
es.
Increased risk to navigational safety and health of humans on vessels as a permanent, hard structure, would pose a significant hazard, restricts transit access
Significant environmental impacts during construction. Significant ongoing impacts due habitat change. It would significantly change the sedimentation dynamics north and south transit. Significantly impact upon sensitive receptors (permanent destruction) of seagrass. It would act as a barrier for marine fauna – preventing their movement between feeding/life cycle habitats. Footprint would reduce the marine area of the Great Barrier world heritage area depending on size of structure.
Sediment barrier would sit in some of the Anchorages beyond port limits, reducing their availability for vessels. The barrier would need significant maintenance – removing sediment building up (otherwise the bay would become even more shallow), maintenance after severe weather events, maintenance on navigational lighting required the length of the barrier. The sediment barrier may not actually prevent sediment buildup, and would pose a risk during severe weather events being so close to the channel – the structure may fall into the channel and cause an obstruction to navigation and port operations.
A significant outlay of capital costs for quarry material, to build the wall. Operational costs for maintenance, especially after cyclones/severe weather events would be significant. The structure would require significant environmental offsets if it could actually be approved by State and Commonwealth governments.
Works may fail to meet or require extensive consideration under the EPBC Act or GBRMP Act
Other approvals needed would include those under: - - The Planning Act 2016
(which includes the Coastal Protection and Management Act, Fisheries Act, Environmental Protection Act.)
- The Environmental Offsets Act 2014.
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Options Issues
Human Health Environment Operations Economic Legislative
Installin
g sed
ime
nt b
arrier d
evices -co
nt
Lan
d p
lacem
en
t / reclam
ation
Increase safety risks due to a large area of waterlogged dredge ponds, and the ongoing management. Increases in land transport movements due to the volume of maintenance material that would come to shore, and associated increases in road accidents due to the increase in land transport. Potential dust, noise, and air emission nuisance issues for the neighboring residents; and increased risk to navigational safety within the Inlet due to floating pipelines used to transfer maintenance dredge material to shore.
Creates potential acid sulphate soil, tail water management issues and greenhouse gas emissions from increases in plant & equipment. Potentially reduces the marine area of the Great Barrier Reef World Heritage Area for any further reclamation, as there is no available land. Does not decrease/change maintenance dredging impacts i.e. water quality, turbidity, disturbance to the seabed, transport and resuspension of contaminants, marine fauna strikes, and underwater noise remain as currently assessed.
Lack of availability of suitable nearby land to treat and store the material. Land is needed for placement of dredge material and be available for long-term management of the area. Maintenance material on land reduces the available capacity for approved capital dredge material land placement areas. Maintenance material has poor engineering qualities, making it not suitability for beneficial reuse without further treatment and stabilization.
Increases cost of dredging campaign by up to 8 times the current cost. The significant cost of purchasing suitable reclamation areas or new land near the port, to place, treat, and store the material. Significant cost of clearing/preparing that land to ensure it is suitable to take the proposed material. Significant cost of treating the maintenance material for PASS/ASS to ensure no further environmental impacts are created.
Approvals triggered under: - - The Planning Act 2016
(which includes the Coastal Protection and Management Act, Fisheries Act, Environmental Protection Act.)
- The Environmental Offsets Act 2014
- Potential assessment under the EPBC depending on location
- RAA and AQM etc
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Options Issues
Human Health Environment Operations Economic Legislative
Be
ne
ficial reu
se (i.e
. on
or o
ff-site re
cycling fo
r con
structio
n, fill, p
rod
ucts, e
tc.)
Limited risk due to low contaminant concentrations. Increase in potential noise due to a mid- scale processing plant for onsite recycling. Risks for land placement include: - Navigation risk -
long floating pipelines required to bring material to shore.
- Transport risks – increase in land transport, and increased accident risks
- Dust, noise and air emissions nuisances for the neighbouring residents
Creates potential acid sulphate soil, salt content, tailwater management issues and greenhouse gas emissions from plant & equipment Does not decrease/change the maintenance dredging impacts, and remain as currently assessed
Land is needed for placement of dredge material, for treatment to address poor engineering qualities of the material before it can be used /recycled into a usable by-product. Contaminant treatment not required as concentrations below land-based acceptance levels. ASS / PASS and salinity treatment needed before beneficial reuse could be an option. New onsite processing requires new staff and ongoing maintenance of plant No local markets identified to take maintenance dredging material, with its poor engineering qualities, ASS/PASS and salinity issues that all require treatment to prevent further impacts to the potential receiving environment/area.
Increases cost for treatment, and treated material remains uneconomic compared to existing onshore supplies in the region. Onsite processing is cost prohibitive to startup and can be cost prohibitive for ongoing operational/maintenance costs. Cost for royalties that may still be required to be paid on end-product (once maintenance dredge material has been processed and converted into a viable by-product). Increase in costs for transportation (given unlikely presence of ongoing local demand or identified reuse market), cost to pay royalties in removing the material from state lands. The maintenance dredge material generated is considered uneconomic to reuse or recycle for construction, fill or any other product compared to existing onshore supplies.
Would trigger approvals under: - - The Planning Act 2016
(which includes the Coastal Protection and Management Act, Fisheries Act, Environmental Protection Act.)
Fails to meet requirements of Queensland’s Coastal Protection and Management Act. Other approvals
needed would include those under: - - The Planning Act 2016
(which includes, Fisheries Act, Environmental Protection Act.); and
Potentially the Environmental Offsets Act 2014
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Options Issues
Human Health Environment Operations Economic Legislative
Be
ach N
ou
rishm
en
t
Hab
itat resto
ration
Limited risk due to low contaminant concentrations. Increases in land transport (truck movements) due to the volume of maintenance material that would come to shore. This then increases road accidents due to the increase in land transport. Increases potential dust, noise, and air emission nuisance issues for the neighboring residents, and the area surrounding any habitat restoration.
Creates potential acid sulphate soil, salt content, tailwater management issues and greenhouse gas emissions from plant & equipment Does not decrease/change maintenance dredging impacts, and they remain as currently assessed.
Poor engineering qualities of material require treatment before material could be utilised in habitat restoration projects. The material also requires dewatering prior to being moved to the designated site, along with treatment for ASS/PASS and salinity, depending on where habitat restoration may be required
Majority of maintenance material is not suitable as it does not meet Queensland Government’s conditions on beach nourishment approvals. Maintenance material has poor engineering qualities that requires treatment before reuse and is not stable enough to remain onshore as beach nourishment.
Increase in costs for transportation to appropriate beaches, increase the cost to pay royalties in removing the material from state land; and it is uneconomic to use this material, given the quality and consistency of material available from other existing onshore supplies within the region. Increase cost or truck/barge movement to move material to the designated site.
Would need approvals under: - - The Planning Act 2016
(which includes the Coastal Protection and Management Act, Fisheries Act, Environmental Protection Act.)
Conflicts with Fisheries Reg and Policies – pacing dredge material on tidal land
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Options Issues
Human Health Environment Operations Economic Legislative
Land
fill
Lan
dfill
Limited risk due to low contaminant concentrations. Increases in land transport (truck movements) due to the volume of maintenance material that would come to shore. This then increases road accidents due to the increase in land transport. Increases potential dust, noise, and air emission nuisance issues for the neighboring residents.
Creates potential acid sulphate soil, salt content, tailwater management issues and greenhouse gas emissions from plant & equipment Does not decrease/change maintenance dredging impacts, and they remain as currently assessed.
Treatment required to address poor engineering qualities of the material. Treatment would also be required for ASS/PASS, salinity and dewatering prior to placement in landfill. Contaminant treatment not required as concentrations below land-based acceptance levels
Landfill operators unlikely to accept the volume of material generated, due to their site volume limitations. Landfill placement also increases cost for treatment, transportation and royalties.
Volumetric forecast not yet completed
Would need approvals under: - - The Planning Act 2016
(which includes the Coastal Protection and Management Act, Fisheries Act, Environmental Protection Act.)
Approvals for an operating landfill facility required.
Se
a Place
me
nt
Limited risk due to low contaminant concentrations. Minor navigational impacts from a TSHD, however these are considered to be low, as the vessel highly maneuverable and scheduling of the inner harbour allows for dredging around ships berthing.
Results in limited short and long-term impacts at sea DMPA to water quality, removal of existing habitats, burial and smothering of organisms on the seafloor.
Potential dredging impacts remain, including dredge plumes are localised to the source point. Placement in the DMPA is away from sensitive receptors and GBR reef
Does not require any additional plant & equipment other than the dredge vessel. The TSHD is a fast, mobile vessel, which limits impacts to normal shipping and port operations
No costs for treatment and transport beyond the normal dredge running costs No ongoing management, however, significant input into monitoring and testing the associated parameters as required under permit conditions.
Approvals needed under: -The Planning Act 2016 (which includes the Coastal Protection and Management Act, Fisheries Act, Environmental Protection Act.); - Commonwealth’s
Environment Protection (Sea Dumping) Act 1981; and
- Landowners consent for placement areas.
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5.5. Selected Future Dredging and Disposal Strategy
For the volumes and rates of sedimentation that influence the demand for maintenance to the channel and
swing basin, the past and present practice of annual campaigns by a trailing suction hopper dredge (TSHD)
and grab dredging for inner port berths and marina is considered the most balanced approach. It is
adaptable to demand and can be scheduled to fit with the availability of the vessels as they transit north or
south to other QLD ports each year. The equipment is also of a scale and nature that it is very efficient for
the type of material moved.
Maintenance of the channel profile, established in 1990, has been managed under the various past LTMPs.
The CSDP capital dredging scheduled for 2019 to widen portions of the channel bend and deepen it will
result in a forecast increase in annual maintenance of around 3-5% of present annual volume. This is
considered to be within the inter-annual variability of sediment accumulation under the present setting.
Further detailed forecasting and consideration of the requirement will be documented in the application
assessment for the next GBRMP permit period, and incorporated in future versions of this LMDMP.
Modelling and Impact Assessment presented within the CSDP RD-EIS process has included consideration of
future dredging and disposal as well as a number of components that are equally applicable to both capital
and maintenance, especially the utilisation of a TSHD and grab/backhoe dredge.
Based on the above, the identified preferred option for management of sediment over the five and 10-year
horizon is TSHD, grab dredging, and bed levelling as is presently conducted. Considerable investment has
been made to ensure a thorough understanding of, and monitoring framework in place for, this option.
As described in Section 5.4, the outcomes of the CSDP RD-EIS, in respect of landside placement of dredge
material from maintenance activity at the Port of Cairns is unviable based on quality and quantity dredged
on an annual basis. Approval will continue to be sought to use the identified off shore disposal sites.
The process for review of sediment management options in future years and through versions of this
LMDMP will be guided by future monitoring outcomes, policy and regulatory change, and a contemporary
consideration of leading practice sediment management, as outlined in the MDS.
6. Risk Assessment Framework
For the management of maintenance dredging for the Port, the applicable risk assessment framework utilises contemporary environmental impact assessment process, applicable to address the respective regulatory agency requirements with responsibilities for approvals of either dredging or placement.
Detailed evaluation of potential impacts and risks has been documented in the two most recent long term
management plans (2005-2010, and 2010-2020) where a range of aspects and impacts have been the
subject of impact hypotheses testing, risk and impact assessment and determination of applicable
management measures to address identified risks
The environmental impacts of dredging at Cairns Port have been studied and documented during past
dredging campaigns. As such, the following assessments of potential impacts are based on information
drawn from these studies and from longer-term environmental monitoring undertaken in Cairns
Harbour/Trinity Bay and Trinity Inlet.
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Assessment of impacts of ongoing maintenance dredging must be undertaken in the context of historical
dredging and spoil disposal activities and the ongoing requirements for maintenance dredging at Cairns
Port.
In 2006, monitoring requirements for the 2005-2010 permit period were consolidated into the Cairns
Harbour Dredging Long Term Dredge Spoil Disposal Management Plan (Years 2 to 5) (CPA, 2006). This plan
was approved by the TACC and Determining Authority. The required monitoring program, with
commentary on the status of implementation and outcomes and demonstration of compliance was
included in the Port of Cairns LTDSDMP 2010-2020.
The present Port of Cairns LTDSDMP 2010-2020 is built on the findings of the past five years of monitoring,
and provides an update with contemporary understanding of routine maintenance dredging impacts in
Cairns Port, and makes conclusions regarding predicted impacts for maintenance dredging at Port of Cairns
in the 2010-2020 permit period. The risk assessment process and management strategies, as well as the
monitoring required to gauge effectiveness of those actions, is outlined in Section 7 of the Port of Cairns
LTDSDMP 2010-2020.
The risks and impacts can be defined as either short or long-term. Short-term effects may include physical
removal of benthic habitat, smothering and burial of benthic organisms at the spoil ground, impacts to
water quality and receiving organisms and injury to significant megafauna. Long-term effects relate to
changes in habitat conditions, such as significant sediment mobilisation to outside the spoil ground.
Table 14 Risk Assessment Summary- Impacts of Dredging to and from Aspects of Trinity Inlet
Issue Risk Receptor Potential Impact Details Likelihood / Consequence
Residual Risk
ENVIRONMENTAL
Turbidity generated during dredging
Sensitive receptors: Coral, Seagrass and Benthic communities
Temporary smothering of sensitive receptors
Temporary turbidity plumes localized to source point, or within/ directly adjacent to, the channels, inner port
Likely /
Insignificant
Low
Turbidity generated during maintenance material placement in DMPA
Sensitive Receptors: Coral seagrass benthic communities
Temporary smothering of sensitive receptors
Negligible impact, placement area is 10km+ from sensitive receptors (i.e. corals), with temporary seagrass presence when conditions are suitable for possible seed germination or colonization under favorable conditions. Temporary impact at DMPA – with a limited change seafloor profile for benthic communities. The 1nm diameter DMPA, would register a change of <10cm for a full year.
Likely /
Insignificant
Low
Underwater noise during dredging and placement
Megafauna Masking megafauna communications; impacting on hunting behavior
TSHD is a mobile vessel; noise production monitored for dredge plant; dredge vessel operates within noise modelling volumes. Low numbers of mega fauna recorded locally.
Rare /
insignificant
Low
Dredge vessel strike
Dolphins, whales, dugongs
Death/injury of protected megafauna species
Dredge is, mobile, with high bridge tower for visual observations of animals within a 300m radius.
Rare /
moderate
Low
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Issue Risk Receptor Potential Impact Details Likelihood / Consequence
Residual Risk
Most megafauna can readily avoid the dredge
Dredge draghead entrains a turtle
Turtles (including listed turtle species)
Death/injury to turtles
Dredge dragheads have turtle diversion devices installed. The suction of dragheads only permitted while the draghead is on the seafloor (i.e. not mid water column)
Possible /
insignificant
Low
Dredge draghead entrains other marine fauna
Fish, eels or sea snakes
Death/ injury to marine fauna
Dredge dragheads have diversion devices installed. The suction of dragheads only permitted while the draghead is on the seafloor (i.e. not mid water column)
Rare /
insignificant
Low
Introduction of marine pests via dredge vessels
Local and regional marine ecosystems
Introduction of pest species to Trinity Inlet and Bay
All vessels must comply with State and Commonwealth Biosecurity Legislation (quarantine, ballast water management, inspections and declarations). Marine biosecurity monitoring in Inlet and as part of annual SAP process
Rare /
Insignificant
Low
OPERATIONAL AND TECHNICAL
Dredging or placement activity impedes commercial traffic
Commercial fleet Local and regional community
Temporary commercial disruptions
Temporary delays only (<hour) in production and operation for commercial operators. TSHD highly maneuverable, allowing for movement around other vessels
Unlikely / Minor
Low
Severe weather disrupts dredging resulting in a reduction of depth, restricting all shipping movements
Commercial fleet Local and regional community
Temporary disruption
Temporary, short-term delays (days), disrupting all operations in and out of the channel. TSHD can return readily from stand by and has high production rates to clear infrastructure, reducing further downturn for operations. RHM to re-declared depths.
Unlikely / Serious
Medium
Dredging or placement activity impedes recreational traffic
Recreational fleet Local community
Temporary disruption
Temporary delays (<hour) in and out of channel by TSHD, and Willunga are both mobile dredgers, allowing movement around operations area
Unlikely / insignificant
Low
Legislative increase in land placement
Commercial fleet Local and regional community
Ongoing disruption; navigation hazards; delays in operations
Absence of land available for placement. Approval delays restrict dredging of infrastructure. Options assessed as part of approvals process and adequate volume forecasting in LMDMP and permits to State and Commonwealth Governments required.
Rare / Major
Low
ECONOMIC
Legislation increases land placement, increasing the cost of maintenance dredging
Local community; Regional community and Queensland
Temporary loss of port for trade/transport impacts network of supply chains due to increased cost for normal port operations
Medium term (months) negative impacts, including increased costs to consumers. Adequate volume forecasting required in LMDMP and relevant approvals by State and Commonwealth Governments,
Unlikely / Minor
Low
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Issue Risk Receptor Potential Impact Details Likelihood / Consequence
Residual Risk
Dredging or placement activity impedes commercial traffic
Commercial fleet Local and regional community
Temporary commercial disruption
Temporary delays (<hour) in production and operation for commercial operators. TSHD highly maneuverable, allowing or movement around other vessels
Unlikely / Minor
Low
Loss of infrastructure depth following a cyclone
Local community;
Restricted access to port for transport, impacts network of supply chains
Temporary, short-term (weeks) negative impacts in production in and out of the Port.
Unlikely / Serious
Medium
Regional community and Queensland
TSHD can arrive readily if in QLD and has high production rates to clear infrastructure, reducing further downturn for Port operations. RHM to re-declared depths.
SOCIAL AND CULTURAL
Community disturbance by dredge (light, noise, fumes)
Local community Loss of amenity Short term (hours) localized impacts to within the vicinity of the dredge vessel
Unlikely / Insignificant
Low
Dredging or placement activity disrupts water traffic
Recreational and/or commercial vessels Local community
Temporary disruption
Temporary delays only (<hour) in production and operation for vessel operators. TSHD vessel highly mobile in channel
Unlikely / Insignificant
Low
Visual impact from dredging or placement
Local community Temporary disruption
Temporary turbidity plumes (hours) localized to the source point, or within/ directly adjacent to, the channel; and placement area is >10km from the coast or Green Island/GBR reef systems.
Unlikely / Insignificant
Low
Cultural heritage (indigenous and non- indigenous) impacted by dredging
Local traditional owners Local community
Disturbance of cultural artefacts Impact on cultural important marine species
Campaign EMPS’ and Cultural Heritage Management component and overall ACH Duty of Care prevails to report any artefacts that may be found. Impacts on culturally important marine species addressed in above Risk Assessment.
Unlikely / Minor
Low
Consistent with the MDS, before each dredging campaign since 2017 a risk assessment of potential impacts to environmental, social or cultural values has been undertaken and documented via the “Annual Risk Assessment” and “Advice Form”. The assessment will assist in refining management measures to avoid, reduce, or mitigate impacts. Identified measures are incorporated into revisions of the respective campaign-specific Environmental Management Plan (EMP) plans for either the TSHD Brisbane or the Grab Dredge Willunga.
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7. Identification and Treatment of Key Risks
Ports North is committed to minimising and managing potential impacts from dredging and dredge material relocation as far as practicable.
Risks from dredging and placement have been assessed through past processes of aspects and impacts assessment, or impact hypothesis setting and testing. These are consistent with contemporary environmental impact assessment methods, such as those defined by the Commonwealth and State application assessment guidelines, and have most recently been demonstrated via the CSDP EIS process.
In a general context, the potential environmental impacts and key risks from dredging and disposal of
dredged material as identified in Section 6 include:
increased turbidity and reduced light availability (i.e. light attenuation);
ecological impacts (direct and indirect) due to disruption of the bed e.g. on benthic fauna communities, sea grasses and corals;
contaminant release (including impacts associated with extraction or disturbance of acid sulfate soils) impacting on water quality;
increased sedimentation affecting sessile flora and fauna;
modifications to physical and habitat processes resulting from changes to bed topography (depth, channel profiles), hydrodynamics (current, wave action);
changes to habitat features and process upon which fisheries depend;
the introduction or spread of pest species, and;
direct (harm) and indirect (e.g. behavioural) impacts on other aquatic fauna, including migratory species and protected species.
The risk and extent of direct and indirect impacts on environmental values is influenced by a range of factors such as the:
- volume of material being dredged; - sediment characteristics including the presence of elevated levels of contaminants; - duration and timing of the dredging campaign; - dredging, transport and disposal methods; and - proximity of sensitive receptors.
Maintenance dredging activities occur within areas of existing and repeated disturbance. Although it is
likely that floral and faunal recolonisation may occur within previously dredged areas between
maintenance events, further impacts on these communities are rarely regarded as key considerations in the
assessment of maintenance dredging applications. This is primarily due to those impacts being largely
unavoidable and that recolonising biota is well-adapted to surviving within dynamic benthic habitats.
The process and stages of risk identification are generally consistent with those outlined in in Figure 24.
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Figure 24 Risk Management Process (from MDS, 2017)
Depending on the scale and frequency, dredging and dredge material placement activities have the
potential to adversely impact on sensitive environmental receptors, social or cultural values associated with
the Port.
Impacts can occur over a short or long term and can be direct or indirect. Dredging related impacts can
result from:
the direct removal of benthic habitat in the vicinity of the dredged area
smothering of benthic organisms in offshore dredge placement locations
changes to marine water quality from increased turbidity and sedimentation
mobilisation of contaminants released from dredged sediments
collisions and disturbance from vessel movements
increased noise and lighting from dredge vessel operations.
Based on the results of the initial risk assessment, targeted and ambient monitoring and established best
practice; a set of key management strategies and actions to minimise the impact from dredging and dredge
material relocation operations will be identified and incorporated into the delivery of any future
maintenance dredging, generally following the scheme shown in Figure 24.
These measures should, if necessary, be supplemented and enhanced with the ongoing real time inputs
from the adaptive monitoring program.
The primary component will be the implementation of an EMP for each campaign either developed by the
contractor, or by Ports North, including regular training and awareness of the EMP applicable to the
operation of the Willunga and to which the contractor and Ports North staff adhere.
Such plans have been in place since the mid-2000s and are accessible on request or in future via the Ports
North website.
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8. Environmental Management
This section includes the treatment options, through sound environmental management, of identified key
risks, and covers a number of areas also addressed in the treatment of key risks component of the Port of
Cairns LTDSDMP 2010-2020.
These hypotheses have been and will continue to be tested by the monitoring programs instigated either
annually or periodically as set out in the Table 15 which includes sediment sampling, plume monitoring,
water quality sampling, seagrass and benthic invertebrate monitoring as well as hydrographic surveys. The
Long-term Monitoring Schedule for the proposed permit period is displayed in Table 16.
Environmental management of maintenance dredging will follow this approach to provide a repeatable structure for planning and executing maintenance dredging activities at Cairns.
This provides certainty for staff, TACC members and regulators around how dredging activities will be
planned and managed. This will also be key to supporting long-term permit applications. Stakeholder
consultation will occur throughout planning including during any dredging program design, execution
and ongoing monitoring and management.
The approach follows processes outlined in relevant key policy documents. These include the:
The National Assessment Guidelines for Dredging (NAGD) assessment framework for ocean disposal
Queensland Maintenance Dredging Strategy for Great Barrier Reef World Heritage Area Ports
Long Term Monitoring and Management Plan Requirements for 10 year Permits to Dump Dredge Material at Sea.
Steps to plan and prepare each dredge campaign will address the following:
Identification of Port navigation needs, risks and sediment management approaches Dredging program design, execution and control Management Measures –such as management plans and contract details, to give effect to compliance
with approval conditions, through operational controls (described below) Monitoring – to gauge the effectiveness of operation and management actions, and respond through
adaptive management of the maintenance activity. A schematic of how these approvals and plans align is depicted in Figure 25.
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Figure 25 Management Plan and Approval Structure
8.1. Objectives
The environmental management objectives relevant to maintenance dredging are as follows:
Ensure that maintenance dredging activities do not impact the OUV of the GBRWHA by minimising or
avoiding impacts to marine ecological values (species, communities and habitats) at the location which
contribute to the OUV of the GBRWHA.
Ensure there are no significant (DEWHA 2009; State of Queensland 2014) long-term changes in the
health of (and no net loss of) high ecological value sensitive receptors such as coral reefs and seagrass
meadows.
Ensure appropriate marine ecological condition monitoring is undertaken to inform adaptive
management actions that aim to minimise or avoid impacts to marine ecological components, process,
and services.
Ensure direct impacts are confined to the dredge-loading site (dredged footprint) and within the
offshore DMPA, and that any impacts outside of these footprint are short-term and reversible.
As dredging operations and information relating to the status of marine ecosystems may change over time,
continual improvement mechanisms will be implemented to ensure that the management and monitoring
program described in this Section specifically addresses potential impacts and issues of concern to
stakeholders. Where relevant, information from the monitoring programs will be used to inform any
required changes to the maintenance dredging program to ensure that the management objectives are
achieved.
Environmental Managemnt System EMS
Approvals:
-Sea Dumping & Marine Parks Permit
-Environmental Authority (ERA16 approval)
Cairns
LTDSDMPDredge EMP's
Bucket Dredge e.g. "Willunga"Routine Inner Port
Maintenance
Navy Base Bed Levelling
Trailing Suction Hopper Dredge e.g. "Brisbane"
Annual Channel Campaign
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In the context of these objectives and
the continuous improvement
approach outlined above, Ports North
proposes to undertake monitoring of
the marine environment where:
sensitive or particularly high
environmental value habitats
may be adversely affected
through the maintenance
dredging activities; or
there are gaps in knowledge or
some uncertainty regarding the
extent of potential impact and
confirmation of assumptions or
previous monitoring is considered
warranted.
8.2. Operational Control
Two key operational controls are enacted in regard to the regular maintenance at the Port of Cairns,
namely, the contract with the Port of Brisbane Pty Ltd for the TSHD Brisbane, and when used, East Coast
Maritime (for the bed level vessel Pacific Conquest), as well as the implementation of the works specific
EMPs developed by those operators who act under contract with Ports North.
An EMP mechanism provides the operational practices required for dredging activities to meet
environmental standards and forms the operational control document to ensure all site-specific
environmental aspects, impacts and potential issues are adequately addressed. The EMPs contain:
Location and description of the activities
Timing of the dredging operations
Measures to meet permit conditions
Standard management measures relating to: o Waste management o Ballast water management o Bunkering of fuel o Vessel wash-down
Adaptive management measures relating to: o Water quality o Marine fauna o Climate conditions o Operation and incident reporting o Emergency procedures and contacts o Records and Reporting o Auditing- Continual Improvement
Figure 26 Dredge Management and Monitoring elements
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The campaign-specific EMPs are developed in alignment with the Risk Assessment Framework (Section 6)
to ensure an appropriate standard of risk assessment, quality assurance and document control. They detail
the specifics of managing a single dredging campaign and include the following:
approval conditions;
risk assessment in accordance with the framework outlined in the LMDMP;
relevant management threshold triggers (e.g., water quality, seagrasses and corals, as determined by the risk framework);
any important ecological and environmental timings that should be considered or windows to be applied to the planned campaign;
specific, targeted management and mitigation measures (including project-related and process-related management actions) applying to the campaign; and
details on how these management measures align with the Port’s overall EMS.
The EMP addresses key operational risk areas including, but not limited to:
ensuring direct impacts remain within the existing lawful footprints of channels and the DMPA;
the management of water quality and the minimisation of the generation of turbid plumes;
minimising the risk of introduced marine pests;
minimising impacts to other users of the operational environment;
ensuring hydrocarbons and chemicals are handled and stored in a manner than minimises the potential impact on the environment and that spills are appropriately managed;
ensuring best practice management for the handling and storage of waste;
minimising noise, vibration, emission and light nuisance;
mitigating impacts to flora and fauna (including megafauna species);
cultural heritage considerations;
processes for non-conformances, incidents and complaints;
processes for emergencies;
performance indicators and corrective actions; and
record management and reporting requirements.
8.3. Adaptive Management
Adaptive management provides for continuous monitoring, evaluation and adjustment of management response measures based on monitoring and environmental condition, and on an understanding of acceptable environmental condition, and thresholds for impact. A series of response levels (triggers) can be established and then monitored to ensure conditions that may produce environmental harm are avoided or ceased before impacts occur.
The primary monitoring program for the Port of Cairns – namely the “Cairns Harbour Long-Term Seagrass
Monitoring Program” has informed the management of past campaigns, where findings from that program
indicated minimal influence for the duration of port dredging, provided confirmation that no adaptive
management actions were required and dredging of that scale could continue.
However, adaptive monitoring will be implemented for each maintenance dredging campaign. The
program is focused on collection and analysis of data to detect potential for environmental harm and
undertake corrective action where necessary. This is a key step in impact avoidance and management.
Campaign specific actions have included risk assessment and the adaptive monitoring and management
programs which focus on water quality, weather conditions and marine flora. Responses to monitoring
results will be required if trigger events occur. The nature of the response is scaled according to the level
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of environmental risk. Such an approach would be reflected in the monitoring plan component of the
EMP for any such future maintenance dredging works.
8.4. Contingency Planning
Although management measures employed by Ports North and the dredging contractor during maintenance dredging cover most potential impacts, contingency arrangements are required in the event of emergency or abnormal operations. Potential emergency or abnormal operations are assessed in accordance with the Risk Management Framework (Section 7). Contingency planning and emergency response during dredging operations is detailed in the respective campaign specific EMP’s.
8.5. Dredging Program Design, Execution, and Control
Where TSHD is conducted, the next stages from the sediment management framework include design of
the dredging program, namely the extent and parameters of dredging per channel segment, and within the
constraints of the relevant approvals that prevail.
Where maintenance dredging and dredge material disposal are identified, planning for all aspects of the
program is undertaken, and includes:
Timing and duration of the dredge program Location of dredging areas and volumes Equipment needs and standard procedures (TSHD Brisbane or other suitable dredge) Identification and assessment of potential impacts to values at dredging and disposal sites Mitigation and management measures (including adaptive management) to address potential
impacts to values Operational controls Monitoring requirements
All elements of the above framework, including consultation, monitoring and supporting studies, aid in the
design of individual dredging programs, along with additional standard dredging procedures and guidelines,
which have informed and are incorporated into the dredge contract and work methods.
8.6. Introduced Marine Pests
Introduced marine species are species translocated to regions outside their natural range, typically by the
passage of vessels nationally and internationally. Where these species present a threat to human health or
environmental and economic values, they are termed a ‘pest’. Outbreaks of marine pests are an obvious
possible risk at ports trading with international clients. Translocation of marine pests may occur via:
- Ballast water - used to control the trim and draft of a vessel;
- Fouling - encrusting organisms via fouling of vessels (e.g. hulls, propellers, intake grates etc.).
Any dredging plant or equipment contracted to undertake dredging works will be required to comply with
marine pest protocols. This includes the National and Queensland bio-Security requirements in relation to
ballast water and marine pest management, the National System for the Prevention and Management of
Marine Pest Incursions and, in particular, the National Biofouling Management Guidance for Non-Trading
Vessels.
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The equipment typically used for activity at the Port of Cairns, is based in Brisbane (TSHD Brisbane) or
Gladstone (Pacific Conquest) and work in Queensland waters. This means a lower translocation risk due to the
operation in Australian waters only and compliance with National standards.
9. Monitoring Framework
Ports North has in place a framework for monitoring that includes a process for responding to the findings as they arise, and then for actions where there is a need to carry out monitoring of dredging or bed levelling operations, which may include monitoring of dredging plumes and sediment transport during dredging. This is complemented by the long-term monitoring of the health of the seagrass meadows and understanding hydrodynamics of the Port to help predict any potential impacts.
Dredging related monitoring is detailed in the Port of Cairns LTDSDMP 2010-2020.
Ports North will oversee the implementation of the monitoring plan, with each component being
undertaken by appropriately qualified staff and marine scientists.
Overall, the monitoring plan is made up of a combination of regular ambient monitoring (long-term
monitoring) and individual dredging event related monitoring (impact and real time monitoring)
determined by the information needed for each campaign. The environmental monitoring plan aims
to:
Assess the long-term ambient environmental health of the Port and nearby sensitive receptors. Detect any impacts from maintenance dredging, both immediately after dredging campaigns and over
time. Respond to real time environmental conditions during maintenance dredging to prevent serious
environmental harm. Collect data that will be used to drive continual improvement.
These aims will be met through the implementation of a tiered approach to monitoring. The tiers may
include ambient, impact, and adaptive monitoring commensurate with the scale of activity. Results from
each tier of the monitoring program will be used to inform the relevant stages of the dredging
management framework.
The above evaluation of potential aspects and impacts and subsequent management options, give rise to
the following monitoring elements considered suitable for implementation to ensure the condition of the
environment in and around the Port is understood and checked periodically.
The program proposed in this section is a revision of the program which has been in place since 2010
(Section 4.1.2) as set out in the Port of Cairns LTDSDMP 2010-2020. This program was informed by the risk
identification and management actions determination process. It was developed through consultation with
the TACC and regulatory authorities, reviewed and endorsed in 2010. It takes into account the outcomes of
previous monitoring, which have and will continue to be a standing agenda item for TACC consideration
each year. It is envisaged that, consistent with the long-term status of maintenance dredging and the
ongoing need for monitoring outcomes, a continuity of the areas of monitoring is to continue generally
consistent with Table 15 below and informed by subsequent review and input from regulators and TACC.
Ports North also contributes to regular ambient monitoring (long-term monitoring) for the harbour
catchment via the Wet Tropics Healthy Waterways Partnership.
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Ports North reviews the reports provided by some port tenants, who have obligations under their
Environmental Authorities. Such monitoring is a compliance action overseen by the State Environment
Department. Leases on port land may also be required to provide periodic reporting to Ports North on the
outcomes of such monitoring. This informs Ports North’s understanding of the activities and possible
contributions from those activities into the broader port environment.
Table 15 Long-term Monitoring Schedule
Monitoring Component
“Ambient Port Health” or Compliance
Impact Hypothesis Activity Description Timing
An
nu
al
Pe
rio
dic
Sediment quality
Compliance Disposal of dredged material will not result in contaminant related impacts to the marine environment
Disposal Sediment sampling and analysis in accordance with approved SAPs and comparison of levels to screening limits outlined in NAGD
Y
Water quality
Ambient and Compliance
Sediments generated during dredging and disposal do not subsequently reach sensitive areas in amounts that would be harmful to the ecological value and amenity of the area
Dredging and Disposal
Water quality monitoring adjacent to loading activities.
Y
Dredging Water samples collected from within the dredge plume (dredge site) and adjacent areas and analysed for trace metals and nutrients.
Y
Benthic habitat and communities
Ambient Maintenance dredging activities do not result in impact to sensitive receptors. and The deposited material does not result in long term changes to benthic communities outside DMPA.
Dredging Monitoring for seagrass adjacent to loading activities. Port baseline surveys (each 3yrs)
Y
Ambient Disposal Benthic fauna and flora sampling and particle size analysis at sites within and adjacent to DMPA (every five years)
Y
Hydrographic survey
Compliance The deposited material does not result in navigation hazards within and adjacent to the DMPA.
Disposal Hydrographic survey of DMPA, as well as pre and post surveys of channel
Y
Marine Pests Ambient Maintenance dredging does not result in the introduction of marine pests into new environments within the port area
Dredging and Disposal
Survey of the location of and status of marine pests within the port
Y
Ambient data sets
N/A N/A Baseline Ongoing participation in the WTHWP monitoring program
Y
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10. Performance Review and Governance
A range of measures are enacted to ensure that the process for management of maintenance dredging at the Port and the objectives of this plan are addressed. This includes record keeping, auditing and performance correction etc. The following sections expand on those measures.
The Environmental Code of Practice for Dredging And Dredging Material Relocation (Ports Australia 2016)
identifies that “transparent and open information sharing is important to improve knowledge and to
understand community values, client needs and government expectations. Communication and reporting is
an important component of this, to demonstrate performance and provide for community accountability”.
In fulfilment of this principle, reporting under this Plan will involve:
regular updates to the TACC on any planned or conducted dredging activities
publication (on the Ports North website) of an annual report detailing:
dredging activity in the past 12 months
results of any environmental monitoring associated with dredging actions
indications of any possible upcoming dredging activities.
For any operations covered by a Commonwealth Sea Dumping Permit, an annual report that meets the
International Maritime Organisation’s reporting requirements will be submitted to the Australian
Government each year. The report will summarise the dredging and disposal monitoring activities
undertaken during the year, including:
permit number
permit start and expiry dates
locations and type of material dredged
volume dredged at each location
disposal locations used
disposal method used
10.1. Record Keeping
During dredging activities Ports North (or its contractors) will keep records which detail:
• the times and dates of when each material disposal run is commenced and finished
• the position (by GPS) of the vessel at the beginning and end of each dumping run with the inclusion
of the path of each dredge material relocation run
• the volume of dredge material (in cubic metres) dumped for the specific operational period. These
records will be retained for audit purposes
• detail of any spill of oil, fuel or other potential contaminant, details of remedial action and
monitoring instigated as result
• details of any marine mega fauna observations during dredging activities
• time and duration of any alterations to the program, including stop work actions, as a result
of any environmental mitigation measure
Post the dredging program, Ports North will:
• undertake a bathymetric survey of the dredged area and dredge material placement site
• within two months of the completion of the bathymetric survey provide a digital copy of the final
survey results to the RAN Hydrographer, copied to relevant regulatory agencies
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• continue monitoring as per the Port of Cairns LTDSDMP 2010-2020 • Report on outcomes as required under the QLD MDS annual reporting requirements • Consider outcomes of the works and above records in the planning for next year’s works.
10.2. Auditing
This plan is intended to demonstrate commitments to the long-term management of maintenance dredging and placement activities. The plan is supported by a range of prior studies, and builds on past Environmental Management Plans for the port location and in conjunction with a long history of dredge records, campaign specific data and records provided to the respective agencies. Periodic auditing of a number of aspects of both components of this plan, and approval requirements, is set out in the Port of Cairns LTDSDMP 2010-2020. This includes conduct of a third party audit at the start of the 10-year period and at completion in 2019/20. Internal audits of EMP implementation, notifications, checklists and volume records have been enacted over the term to date, with findings demonstrating sound management effectiveness and compliance.
Audits and inspections are undertaken to confirm activities are carried out in line with the defined
requirements set out in this LMDMP and associated management documents, including performance
indicators as audit criteria. Audits and inspections may also include assessing compliance with relevant
legislation or other compliance obligations.
Audits and inspections will be initiated and completed by the Environment Manager or by a suitably
qualified auditor. Audit reports may be provided to external regulatory authorities as and when required.
Audit findings and reports shall be provided to the management team and staff responsible for the
dredging works.
External or third party auditing or review of this plan will be considered by Ports North in parallel with permit
conditions that have similar requirements for the start and end of the existing Marine Park and Sea Dumping
Permit. The initial third party audit, completed in 2009, was of a scope that addressed both permit conditions
and the sub-ordinate documents including the management plans. Such scope is envisaged for future audits
of this and other dredging management documents, and will be resolved via the audit scope approval in
conjunction with the applicable regulatory agency. Outcomes of such audits will be considered initially by
Ports North via review of the LMDMP and then by the TACC to ensure any technical feedback is incorporated
in the response to audit.
10.3. Non-Conformance and Corrective Action
Events such as incidents, complaints and monitoring exceedances result in investigations to determine root
cause and corrective action. The processes for responding to non-conformances are detailed in the respective
EMPs. Reporting to regulatory authorities is undertaken in accordance with the conditions of statutory
authorities relevant to maintenance dredging as described in the EMP.
Corrective actions ensure that the organisation mitigates the reoccurrence of environmental incidents,
complaints and monitoring exceedances and ensures continuous improvement of dredging operations.
Corrective actions identified to manage the dredging operations are detailed for each potential risk category
in the respective EMPs. This incorporates monitoring undertaken under the Environmental Monitoring
program.
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10.4. Internal and External Reporting
To ensure Ports North Management and Board are fully informed of the risks associated with maintenance dredging, reporting is undertaken in accordance with the Risk Management Framework (Section 7).
Reporting to regulatory authorities is undertaken in accordance with the conditions of statutory
authorities relevant to maintenance dredging described in the EMP (Section 10).
Periodic reporting and management review under the Ports Australia Guidelines is also required.
Through the Queensland Ports Association, Ports North participates in comparative analysis and
coordinated maintenance dredging reporting to TMR in accordance with Principal 8 of the MDS and
communicates with the TACC (Section 4).
10.5. Access to Reports and Data
The current approved version of the Port of Cairns LTDSDMP 2010-2020, LMDMP, EMP, and Monitoring
Programs are on the internet for public access. In accordance with Principal 16 of the MDS, relevant
documents or summaries provided to the TACC will be made available. Reporting components required
under the MDS are provided to demonstrate the coordinated maintenance dredging reporting to TMR, in
accordance with Principal 8 of the MDS.
Monitoring and data analysis provides the information required to inform the risk assessment framework,
adaptively manage operations and demonstrate compliance. The data management process ensures
quality assurance and quality control. Monitoring reports and data are held internally, or as per published
reports, are to be made accessible via the external website commensurate with the type of report and its
intent.
Ports North facilitates meetings with the TACC where the outcomes of monitoring programs are reviewed
and discussed. A data access request process is established where information can be requested by
external entities on environmental monitoring data and reports.
10.6. Continual Improvement and Changes to the LMDMP
Review and improvement commitments in line with the MDS Framework have been incorporated into the
management framework for maintenance dredging activities at the Port to ensure consistency with leading
practice management. This framework contributes to the ongoing protection of the GBRWHA and the
Port’s continued operating efficiency over the long term.
This LMDMP will be reviewed and updated at least once every five years, or when one of the following
occurs:
a) when permit conditions have been changed or amended or new permits issued
b) when monitoring results report substantially different impacts than were predicted
c) if an incident occurs that poses a significant risk to effective future management of dredging activity.
The current approved version of this LMDMP will be maintained on the Ports North
website – www.portsnorth.com.au.
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Table 16 Review and Continual Improvement Summary
Document Review Context Interval Key Drivers
Sea Dumping Requirements and LMDMP
Review maintenance dredging and sea disposal requirements. Consider monitoring relating to the consequences of dumping maintenance dredging material into the marine environment and the possibility of avoiding or reducing the need for future dumping of maintenance dredge material at sea by identifying and assessing the viability of long-term solutions and best environmental outcomes. To ensure the LMDMP reflects the most up-to-date understanding of risk, sedimentation processes, options available for sediment management including re-use or disposal, and the management of the impacts of maintenance dredging.
Every five years or as required thru permit renewal preparation
The Reef 2050 Long-Term Sustainability Plan, Commonwealth of Australia, 2015 Maintenance Dredging Strategy for Great Barrier Reef World Heritage Area Ports, TMR 2016. National Assessment Guidelines for Dredging (Commonwealth of Australia, 2009) Guidelines for Long-term Maintenance Dredging Management Plans, TMR 2018
TSHD Brisbane Schedule and Port specific Environmental Risk Assessment
To ensure the TSHD Brisbane’s schedule is developed to optimise environmental outcomes and operational efficiencies by: ensuring identified environmental windows as well as any restrictions imposed on permits are applied; minimising the net risk of impacts at each port by adopting site-specific operating procedures and; avoiding unnecessary dredger travel and relocation. In accordance with the MDS and the QPA procedure, Ports North will define the urgency, volume, and extent of maintenance dredging required and complete a port specific environmental risk assessment for maintenance dredging. Reviews should consider the question of whether the outcomes (of managing maintenance dredging and disposal impacts) are consistent with the objectives detailed in the LMDMPs.
Every year Maintenance Dredging Strategy for Great Barrier Reef World Heritage Area Ports, TMR 2016. Procedure for scheduling and reporting the annual state- wide maintenance-dredging program by TSHD Brisbane, QPA 2017.
Environmental Management Plan (EMP)
To ensure continual improvement by updating the EMP based on the learnings of the previous campaign and ensuring that the EMP reflects the most up-to-date understanding of risks specific to each campaign. Reviews should consider the performance of the previous maintenance dredging campaign and monitoring results; the volume and extent of required maintenance dredging; an environmental risk assessment; updates to scientific research and leading practice management and monitoring techniques.
Every year or as required
Guidelines for Long-term Maintenance Dredging Management Plans, TMR 2018
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Document Review Context Interval Key Drivers
Environmental Monitoring
To ensure that appropriate monitoring and adaptive management is in place Management review is in place for each campaign based on longer-term commitments made in the LMDMP and campaign specific risks and improvement opportunities are identified through the EMP review process. The Monitoring section outlines an adaptive management framework which ensures that risks continue to be actively managed during each campaign.
Every year or as required ongoing
Guidelines for Long-term Maintenance Dredging Management Plans, TMR, 2018.
Based on the proposed transitional arrangements noted in Section 1.2, and the approach or this LMDMP,
such review will occur in consultation with the TACC, stakeholders and regulatory agencies during 2019.
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11. Supporting Information
ANZECC/ARMCANZ (2000) Australian and New Zealand guidelines for fresh and marine water quality. Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand
Commonwealth of Australia (2009) National Assessment Guidelines for Dredging. Commonwealth of
Australia, Canberra.
Commonwealth of Australia (2012) Checklist for Completing Long Term Monitoring and Management Plans
for Dredging. Department of Sustainability, Environment, Water, Population and Communities, Canberra
Commonwealth of Australia (2015) The Reef 2050 Long-Term Sustainability Plan.
Department of Environment, Water, Heritage and the Arts (DEWHA) (2009) Matters of National
Environmental Significance – Significant Impact Guidelines 1.1. DEWHA, Canberra.
Department of Transport and Main Roads (TMR) (2016) Maintenance Dredging Strategy for Great Barrier
Reef World Heritage Area Ports. TMR, Brisbane.
Great Barrier Reef Marine Park Authority (GBRMPA) (2014) Great Barrier Reef Outlook Report, GBRMPA,
Townsville
Great Barrier Reef Marine Park Authority (GBRMPA) (2012), Guidelines on the use of hydrodynamic
numerical modelling for dredging projects in the Great Barrier Reef Marine Park, GBRMPA, Townsville
Haskoning Australia Pty Ltd (2016) Maintenance Dredging Strategy for Great Barrier Reef World Heritage
Area Ports: Technical Supporting Document. Report prepared for the Queensland Department of Transport
and Main Roads.
Queensland Ports Association (QPA) (2017) Procedure for Scheduling and Reporting the Annual State-wide
Maintenance Dredging Program by TSHD Brisbane (Draft). QPA, Brisbane.
SKM (2013) Improved Dredge Material Management for the Great Barrier Reef Region Synthesis Report.
Great Barrier Reef Marine Park Authority, Townsville.
State of Queensland (2014) Queensland Environmental Offsets Policy Significant Residual Impact Guideline
Nature Conservation Act 1992 Environmental Protection Act 1994 Marine Parks Act 2004 December 2014.
EHP, Brisbane.
State of Queensland (2015) Sustainable Ports Development Act 2015 (Ports Act), Department of Transport
and Maine Roads, Brisbane.