Method Breakwater - rock placement.pdf

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Page 1 12 November 2010

Dredging, Breakwater Constructionand Land Reclamation

Management Plan

Document No : 301012-01054-1000-EN-PLN-0003

Revision : Rev 0

Date of Issue : 12 November 2010


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Oakajee Deepwater Port

Dredging, Breakwater Construction and Land Reclamation Plan

PROJECT 301012-01054-1000-EN-PLN-0003

0 Issued for Approval

EMay D. McAlinden D. McAlinden

9-Nov-10 12-Nov-10

D Issued for OPR Review

L.Twomey D.McAlinden D. McAlinden

7-Nov-10 9-Nov-10

C Issued for Internal Review L.Twomey M.Bailey 3-Nov-10 6-Nov-10

B Issued for Peer Review

L.Twomey

M.Mulligan

P.Lavery D. McAlinden

3-Nov-10 6-Nov-10

B Issued for Final Review

L.Twomey

M.Mulligan

D.Lord D. McAlinden

01-Sep-10 13-Sep-10

B Issued for OPR Review

L.Twomey

M.Mulligan

D.McAlinden D. McAlinden

25-June-10

D. McAlinden

25-June-10

A Issued for Internal Review

L.Twomey

M.Mulligan

P. Scott D. McAlinden

17-May-10

D. McAlinden

17-May-10

REV DESCRIPTION ORIG REVIEW REVIEW

OWNER

DATE APPROVED DATE

301012-01054-1000-EN-PLN-0003 Rev 0


NOTE

This report has been prepared on behalf of and for the exclusive use of the proponent/port operator and their contractors.

This report was developed by Oceanica Consulting Pty Ltd using a standard document template and structure supplied by Oakajee

Port and Rail Pty Ltd

Copying this report without the permission of the proponent/port operator is not permitted.


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Table of Contents

LIST OF ACRONYMS AND ABBREVIATIONS ............................................................................................................ 71. INTRODUCTION ............................................................................................................................................. 9

1.1 Background/Project Description ............................................................................... 91.2 Scope and Objective ................................................................................................. 101.3 Description of Key Works ........................................................................................ 141.4 Key Environmental Legislation and Conditions ..................................................... 171.5 Stakeholder Consultation......................................................................................... 24

1.5.1 Peer Review of Baseline Studies ........................................................................................................... 241.5.2 Collaborators .......................................................................................................................................... 251.5.3 Peer Review of Draft EMP ..................................................................................................................... 25

2. EXISTING ENVIRONMENT ...................................................................................................................... 262.1 BPPH Mapping .......................................................................................................... 262.2 BPPH Health.............................................................................................................. 262.3 Water Quality............................................................................................................. 272.4 Sediment Quality....................................................................................................... 272.5

Wind, Currents, Waves and Tide Conditions .......................................................... 27

2.6 Introduced Marine Organisms ................................................................................. 30

3. POTENTIAL IMPACTS............................................................................................................................... 313.1 Method....................................................................................................................... 313.2 Impacts ...................................................................................................................... 323.3 Hydrodynamic modelling of BPPH impacts ............................................................ 37

3.3.1 BPPH loss predictions ............................................................................................................................ 373.4 Water Quality Impacts .............................................................................................. 443.5 Summary of Impacts................................................................................................. 47

4. ROLES AND RESPONSIBILITIES......................................................................................................... 485. MITIGATION................................................................................................................................................... 506. KEY CONTROL MEASURES .................................................................................................................. 527. MONITORING ................................................................................................................................................ 54


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7.1 BPPH Direct Impacts Monitoring ............................................................................. 557.1.1 Parameters ............................................................................................................................................. 557.1.2

Frequency and Location ......................................................................................................................... 55

7.1.3 Method ................................................................................................................................................... 55

7.2 BPPH Indirect Impact Monitoring ............................................................................ 577.2.1 Parameters (Light requirements and thresholds for Benthic Primary Producer Habitat) ........................ 577.2.2 BPPH monitoring zones ......................................................................................................................... 587.2.3 Frequency and Location ......................................................................................................................... 607.2.4 Method ................................................................................................................................................... 66

7.3 Water Quality (Physio-Chemical Monitoring).......................................................... 707.3.1 Parameters ............................................................................................................................................. 707.3.2 Frequency .............................................................................................................................................. 707.3.3 Location .................................................................................................................................................. 707.3.4 Method ................................................................................................................................................... 74

7.4 Return Water Discharge Monitoring ........................................................................ 757.4.1 Parameters ............................................................................................................................................. 757.4.2 Frequency .............................................................................................................................................. 757.4.3 Location .................................................................................................................................................. 757.4.4 Method ................................................................................................................................................... 75

8. CONTINGENCIES AND REACTIVE MANAGEMENT ..................................................................... 778.1 Contingencies/Reactive Management for BPPH Indirect Impacts......................... 77

8.1.1 Management triggered by decline in seagrass cover at impact sites ..................................................... 778.1.2 Management triggered by Hsat exceedances ....................................................................................... 788.1.3 Management triggered by BPPH health exceedances ........................................................................... 78

8.2 Contingencies/Reactive Management for Water Quality Impacts ......................... 798.3 Contingencies/Reactive Management for Return Water Discharge ...................... 798.4 Contingency/Reactive Management Actions .......................................................... 80

9. REPORTING .................................................................................................................................................. 8510. AUDITING & REVIEW ................................................................................................................................ 86


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10.1 Auditing ..................................................................................................................... 8610.2 Review and revision ................................................................................................. 86

11.

RELATED PLANS........................................................................................................................................ 88

12. REFERENCES .............................................................................................................................................. 89ATTACHMENT A......................................................................................................................................................... 92SUMMARY OF COMMENTS FROM THE MARINE ECOSYSTEM BRANCH OF THE EPASU ON THE

DESIGN AND REQUIREMENTS OF BASELINE STUDIES AT OAKAJEE ............................................................... 92ATTACHMENT B......................................................................................................................................................... 96STAKEHOLDER ENGAGEMENT ............................................................................................................................... 96ATTACHMENT C....................................................................................................................................................... 101APPENDIX D: OCEANICA AND APASA (2010), BENTHIC PRIMARY PRODUCER IMPACTS FROM

CONSTRUCTION OF THE PROPOSED OAKAJEE PORT ..................................................................................... 103


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General InformationMin Statement No 469 Project Title Oakajee Deepwater Port

EMP Title Dredging, Breakwater Construction and Land Reclamation

EMP Content Yes No Comments

Is the document structured according to the EMP guideline? -

Element - Is the aspect appropriately described? Section 1

Current Status Are the project description and receiving environment detailsadequate?

Section 2

Potential Impacts Are the potential impacts described adequately? Section 3

Environmental Objectives Are the objectives consistent with the MinisterialStatement and the EPA bulletin?

Section 5

Performance Indicators/Criteria Are the indicators and criteria usedmeaningful, sufficient and appropriate?Are the criteria verifiable and reproducible?

Table 5-1

Table 5-1

Implementation strategy Are the strategies, tasks and the action programadequate for the environmental objectives?Have roles and responsibilities been identified?Have adequate timeframes and priorities been identified?

Section 5

Section 4 and Section 6Section 6

Monitoring Is the program to monitor performance against objectives andcriteria adequate?Are details provided on how/when monitoring will be undertaken and reported?

Section 7

Section 7 and Section 9

Contingencies Are the mechanisms to identify actual and apparent non-conformance adequate?Are the actions to address non-conformances adequate?

Section 8

Section 8

Stakeholder consultation Is a list of major stakeholders and details of howand when they were and will be consulted, provided?

Section 1.5 and Attachment A

Auditing Are details of an audit process to demonstrate implementation andcompliance provided?

Section 10

Review and Revision Is a suitable process to assess the adequacy of theplan detailed?

Section 10

Reporting are the reporting details provided adequate? Section 9

Key Management Actions Table - Has adequate information been providedin the Table?Does the table list the key actions, how implementation will be reported and theevidence that will be provided to DoE?

Section 6

Section 6 and Section 9

Figures and Tables Have relevant figures and tables been provided? Section 1

Advisory bodies Has advice been sought from all relevant advisory bodiesand incorporated into the EMP?Has evidence of this advice been provided with the document?

Requires DEC advice - pending DSDand GPA reviewAs above

Additional Comments

The EMP has been developed inaccord with the DoE EMPguideline.

. Environmental Manager Date


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LIST OF ACRONYMS AND ABBREVIATIONS

Hsat Change in Hours above Saturating Irradiance

AMSA Australian Maritime Safety Authority

ANZECC Australian New Zealand Environment Conservation Council Australian New Zealand

AQIS Australian Quarantine and Inspection Service

ARMCANZ Agriculture and Resource Management Council of Australia and New Zealand

AS/NZS Australian Standards/New Zealand Standards

BPPH Benthic Primary Producer Habitat

CD Chart Datum

CM Construction Manager

CSD Cutter Suction Dredge

DAFF Department of Agriculture, Fisheries and Forestry

DBCLRMP Dredging, Breakwater Construction and Land Reclamation Management Plan

DEC Department of Environment and Conservation

DM Dredging Manager

DSD Department of Statement Development

EAG3 Environmental Assessment Guidelines 3

EMP Environmental Management Plan

EMS Environmental Management SystemEPA Environmental Protection Authority

EPASU Environmental Protection Authority Service Unit

EPBC Act Environmental Protection and Biodiversity Conservation Act

GPA Geraldton Port Authority

HEPA High Ecological Protection Area

Hsat Hours above Saturating Irradiance

IMO Introduced Marine Organism

IMPMP Introduced Marine Pest Management Plan

ISO International Standards Organisation

LAC Light Attenuation Coefficient

LAU Local Assessment Unit

MS Ministerial Statement

MARPOL International Convention for the Prevention of Pollution from Ships


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MEPA Moderate Ecological Protection Area

MEPC Marine Environment Protection Committee

NRA Northern Reclamation Area

OEPA Office of the Environmental Protection Authority

OPR Oakajee Port and Rail Pty Ltd

OIE Oakajee Industrial Estate

PER Public Environmental Review

Sea Dumping Act Environment Protection (Sea Dumping) Act 1981

SEWPaC Department of Sustainability, Water, Population and Communities

SHI Seagrass Health Indices

SQMP Sediment Quality Management Plan

SSMP Shoreline Stability Management Plan

SRA South Reclamation Area

TSS Total Suspended Solids

UNMP Underwater Noise Management Plan


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1. INTRODUCTION

1.1 Background/Project Description

In 1997 a proposal from the then Western Australian (WA) Government Minister for Resources Development led to an

assessment of the Oakajee Deepwater Port concept by the Environmental Protection Authority (EPA), resulting in the

release, on the 25th of February 1998, of Ministerial Statement 469 (MS469) by the then Minister for the Environment.

The Statement established the legally binding environmental conditions under which the Oakajee Deepwater Port

development could proceed, with the original term of the environmental approval extending to the 25 th of February 2003.

The term of the environmental approval has subsequently been extended on several occasions, the current expiry date

being the 25th of February 2013. The Minister for State Development is the proponent for the Oakajee Deepwater Port.

Development of the Oakajee Port has been linked to expansion in the Mid-west iron ore mining sector. The number of

Mid-west iron ore projects currently being progressed has increased the impetus for development of the Oakajee

Deepwater Port which led to the State Government initiating a competitive tendering process from consortia interested in

developing the Oakajee Deepwater Port and associated infrastructure. Following the tender process, Oakajee Port and

Rail Pty Ltd (OPR) was appointed in July 2008 by the State Government as the preferred developer of the Oakajee

Deepwater Port. On the 20th March 2009 the State Government and OPR entered into a State Development Agreement,

which provided OPR exclusive rights to build the Oakajee Deepwater Port and a railway line linking the port to the iron ore

mines to the east.

Consistent with agreements between the State Government and OPR, OPR is preparing the Environmental Management

Plans (EMPs) required as conditions or commitments of MS469 for the Department of State Development (DSD), which is

the agency acting on behalf of the Minister for State Development.

The Oakajee Deepwater Port will be located 24 km north of Geraldton on Western Australia's mid west coastline

(Figure 1.1), and will comprise a large breakwater sheltering up to three berths (being two Cape Class berths plus one

further Cape Class berth or one Panamax berth), a tug and work boat harbour and associated land based facilities

including ship loaders, conveyors, stockpile yard, stackers and reclaimers. Additional facilities may be added at a later

stage (subject to further approvals).

Construction of the port is scheduled to commence in 2011 with current forecasts having the port operational in 2014.

Iron ore exports for the foundation development of Oakajee Deepwater Port are expected to be up to 45 million tonnes per

annum.

The Oakajee Iron Ore Export Development, being part of the broader Oakajee Development that includes provision for the

industrial development in the Oakajee Industrial Estate (OIE), has three key project areas, as outlined in Table 1.1.


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Table 1.1 : Key OPR Project Areas

Area Key Aspects Approval Status

Oakajee DeepwaterPort1 Includes breakwater, harbour basin, three berths, dredging, land reclamationand some port terrestrial aspects including storage area and access corridor.

Excludes quarry.

Approved (MinisterialStatement 469) (includingSection 45C and 46)

2

Port Terrestrial Includes storage stockpiles, ship loader, material handling system, railunloader, desalination plant, administration buildings, rail marshalling yardsand workshop and other associated land based infrastructure

Referred to EPA Nov 2009

Pending Part IV PublicEnvironmental Review(PER)

3

Rail Development Includes 570km rail route and supporting infrastructure Referred to EPA Nov 2009

Pending Part IV PER

1.2 Scope and Objective

This document details the management strategies to be implemented by OPR to ensure dredging, breakwater

construction and land reclamation works and any associated adverse impacts on benthic primary producers and water

quality are managed in an appropriate manner during the construction of the Oakajee Deepwater Port Development.

Extensive dredging will be required in the construction of the proposed Oakajee Deepwater Port. Dredging causes

sediment to be suspended in the water column which adds to the natural turbidity which, in the absence of management

controls, could possibly cause unacceptable environmental impact via the following pathways:

Reduced light penetration to the photosynthetic algae and seagrasses;

Inhibit filter feeding animals and larval recruitment of benthic biota;

Cause mechanical damage to benthic fauna;

Deplete oxygen; and/or,

Cause nutrient enrichment.

1

The proponent for the Oakajee Deepwater Port approval is the Minister for State Development.2 In relation to the Oakajee Deepwater Port area in Table 1-2, Ministerial Statement (MS469) was subsequently released (February

1998) outlining the conditions and commitments that the proponent must meet to construct a deepwater port at Oakajee. The Oakajee

Deepwater Port approval was subject to a recent Section 45C and Section 46 approval granting variation and extension to the existing

approval

3 The Port Terrestrial and Rail Development were referred to the EPA in November 2009 under Part IV of the EP Act 1986 and the

level of assessment for both aspects has been set at Public Environmental Review


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The Approved Proposal for construction of the deepwater port at Oakajee was approved for implementation by the issuingof MS469 (1998).

The Ministerial Condition 5-3(5) and Proponent's Environmental Management Consolidated Commitments (6b)

(Attachment 1 to MS469 dated 28 August 1997) applicable to this Plan (DBCLRMP) are outlined in Ministerial Statement469 (1998) and include:

The proponent will, prior to construction, prepare a Marine Management Plan that will include a Dredge andDredge Spoil Management Plan in the event that the final port plan involves dredging. The Plan will be

prepared in accordance with the requirements of the EPA, upon advice from the DEP, and will include amonitoring program for water quality in and within a relevant distance of the work area. The management

plan and all results of the monitoring programs will be made available to the general public.

The key characteristic of the Approved Proposal relevant to this DBCLRMP was identified in Table 1 of theBulletin 866, as:

6.3.7 Marine area affected up to 170ha

The objective of this document is to:

1. provide guidance during construction to:

minimise impacts to benthic primary producers (up to 170 ha);

minimise impact to marine fauna; and,

minimise impacts to water quality.

2. outline monitoring programs and reporting that will be implemented;

3. ensure OPR operations comply with regulatory requirements with respect to dredging and benthic flora andmarine fauna management; and,

4. enable optimisation of construction works taking cognisance of item 1 to 3 above.

Based on the Ministerial Conditions outlined above, the scope of this DBCLRMP is:

Establish a baseline for the existing water quality and sediment quality within and adjacent to the port.

Establish a baseline for benthic habitat and marine fauna in the Oakajee area.

Describe how the dredging, breakwater construction and land reclamation will be conducted.

Describe the potential marine environmental impacts associated with dredging, breakwater construction and landreclamation, with particular attention to benthic primary producers and water quality.

Define the management measures associated with dredging, breakwater construction and land reclamation that willbe undertaken to reduce the potential for, and minimise, environmental impact during the construction phases ofOakajee Port.

This EMP is to be updated at regular intervals as scheduled within the OPR Environmental Management Systems.


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Figure 1.1: Location of the proposed Oakajee Deepwater Port in Western Australia


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Figure 1.2: Layout of the Approved Oakajee Deepwater Port (Port Marine Project) (Figure 1 Attachment 2 of MS469)


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1.3 Description of Key Works

Construction Phase

The proposed port construction is expected to occur over a 36 month period. The major components will include:

Breakwater construction using land based equipment (i.e. rock placement);

Breakwater construction using rock dumping barges;

Development of a bunded northern reclamation area; and,

Dredging.

An outline construction schedule was developed to assist with development of the hydrodynamic model (APASA 2009a),

which required an indicative schedule of the major construction components. The anticipated schedule to complete each

major construction activity is approximately:

Northern reclamation area breakwater construction 18 months ;

Marine based construction 16 months;

Land based construction 18 months; and,

Dredging 6 months.

It is expected that the major construction activities will overlap so that the full construction campaign will be complete

within a proposed 36 month construction period.

To protect the Oakajee Port harbour waters from prevailing seas and swell, a 2.5 km long (projecting 1.9 km offshore)

rock breakwater will be constructed (Figure 1.2). The breakwater will provide shelter for the port basin and allow

dredging, pile driving and general berth construction to occur. At the same time, a reclamation area abutting the shorelinewill be constructed using dredged material for use as general port land. This area, known as the Northern Reclamation

Area (NRA) will contain up to approximately 1.5 Mm3 of dredge material, while the primary settlement area with a capacity

of approximately 2 Mm3 will be constructed onshore at the Southern Reclamation Area (SRA) (Figure 1.3).

The breakwater will be constructed from granulite rock sourced from a nearby quarry that will be developed as part of the

Port construction. It is expected that rock placement will occur from both land (using excavators) and sea (using barges).

At its highest point the seaward crest of breakwater will stand at a level of 11.0 m Chart Datum (CD) and its design is

capable of withstanding a 1 in 100 year storm event with no more than five percent damage. The seaward walls of the

breakwater will be armoured with rocks up to 30 tonnes in weight. It is expected that the breakwater will take two years to

construct.

Dredging is required in the berth pockets, harbour basin and channel to achieve design depths ranging between -11 m CDin the turning basin and approximately -22 m CD in the outer channel enabling fully-laden Cape class vessels to safely

manoeuvre and navigate the harbour basin and channel (Figure 1.3). To achieve the design depths, dredging of

approximately 2.6 Mm3 of material will be required (Table 1.2). This volume incorporates a 0.5 m allowance for over

dredging (Table 1.2). Dredging will be carried out with a large Cutter Suction Dredge (CSD), which will cut the seabed

material and pump it directly to either of the two settlement and reclamation areas (Figure 1.3). During cutting and

placement of dredged material in the reclamation areas it is expected that the volume of this material will increase to

approximately 3.3 Mm3due to bulking of the in-situ material. The dredge will regularly move locations based on dredging


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and operational requirements as well as sea and swell conditions. The dredge will move using an array of anchors, rather

than being self propelled. The dredge will pump material as a slurry (consisting of solids and seawater) at a rate of

approximately 900 m3/minute to the reclamation areas (Figure 1.3)). It is expected that after an initial period of land

reclamation area filling, the overflow velocity will match that of the input velocity (i.e. 900 m3

/minute).Table 1.2: Approximate Dredge Volumes4

Material Type Design Volume (m3) Design + Over dredge Volume (m

3)

Sand 234,900 256,800

Alluvium 32,900 44,700

Non-Calcreted 693,400 836,100

Calcreted 1,372,700 1,472,400

TOTAL 2,333,900 2,610,000

The reclamation areas have been designed to incorporate a series of settlement ponds to increase retention time to allow

maximum settlement of fine particles prior to returning water to the ocean. The settlement ponds will be managed using a

system of adjustable height weirs and pumps in order to minimise reduce return water turbidity before discharging to the

marine environment (refer drawing 301012-01054-1112-MA-DAL-0009). Overflow from the reclamation areas will be

directed back to the marine environment once the suspended sediment concentration of the return water has fallen to less

than 250 mg/L5. In addition to facilitating the active management of the dredge material and the associated return water,

the placement of dredge material in these reclamation areas will lead to a reduction in future and ongoing requirements for

land based fill material at the Oakajee Port site.

4These volumes are approximate only and serve only to describe the relative proportions and type of sediment

5The return-water turbidity of 250 mg/L was chosen as a worst-case, and has been used in the hydrodynamic modeling (see Section 3.3.1).


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Figure 1.3: Oakajee Port Project Interfaces and Location of Dredge Material Placement


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1.4 Key Environmental Legislation and Conditions

The key legislation and Ministerial Conditions relevant to dredging, breakwater construction and land reclamation isprovided in Table 1.3 .

Table 1.3: Key legislation and Ministerial Conditions relevant to dredging, breakwater construction and land

reclamation

Document Responsible Government Authority Aspect

International Conventions and Commonwealth Legislation

International Convention for thePrevention of Pollution from Ships(MARPOL).

International Maritime Organization

This is the most important convention regulating and preventingpollution of the marine environment by ships. This convention aimsto preserve the marine environment through the completeelimination of pollution by oil and other harmful substances fromships and the minimisation of accidental discharge of such

substances.

Protection of the Sea (Prevention ofPollution from Ships) Act 1983

Navigation Act 1912

Australian Maritime Safety Authority (AMSA)under the Department of Infrastructure,Transport, Regional Development and LocalGovernment (Infrastructure)

These legislations give effect to the MARPOL convention inAustralia.

The Marine Environment Protection Committee (MEPC) is theInternational Maritime Organisation's major technical bodyconcerned with the prevention and control of pollution from ships.

AMSA leads Australia's work in MEPC.

Quarantine Act 1908 Australian Quarantine and Inspection Service(AQIS) under the Government Department ofAgriculture, Fisheries and Forestry (DAFF).

AQIS administers the Quarantine Act 1908 with the objective ofprotecting Australia's animal, plant and human health status, and tomaintain market access for Australian food and other agriculturalexports.

Section 4 of the Act provides measures for the inspection,

exclusion, detention, observation, segregation, isolation, treatment,sanitary regulation and disinfection of vessels, persons, goods,things, animals or plants, and having their object the prevention ofthe introduction or spread of diseases or pests affecting man,animals or plants.

Section 17 of the Act lists the vessels subject to quarantine,including every overseas vessel until pratique has been granted oruntil it has been released from quarantine.

Environmental Protection (Sea Dumping)Act 1981

Department Sustainability, Environment, Water,Population and Communities (SEWPaC)

Waters surrounding Australia's coastlines are protected from wastesand pollution dumped at sea by the Environment Protection (SeaDumping) Act 1981 (the Sea Dumping Act).

Environment Protection and BiodiversityConservation Act 1999 (EPBC Act)

SEWPaC Protects matters of national significance, including listed species offauna, including those in the marine environment.

State Government Legislation

WA Contaminated Sites Act (2003) Western Australia Department of Environmentand Conservation (DEC)

The Contaminated Sites Act (2003) (WA) took effect in WesternAustralia on December 1, 2006. The Contaminated SitesManagement Series was developed to provide guidance for riskassessments prior to activities governed under the Act, andstipulates that Sampling of sediments as part of contaminatedsite assessment/remediation is required where () sediment isrequired to be dredged as part of port/harbourconstruction/expansion works or development in a riverine or marine


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environment (DEP, 2001).

Environmental Protection Act 1986 Western Australia Office of EnvironmentalProtection Authority (OEPA) The key piece of environmental legislation within Western Australia,relating to the prevention, control and abatement of pollution andenvironmental harm, for the conservation, preservation, protection,enhancement and management of the environment.

Western Australian EnvironmentalProtection (Unauthorised Discharges)Regulations 2004

DEC These regulations prohibit commercial activities from dischargingcertain wastes into the environment. The prohibited wastes includepetrol, sewage, degreasers, detergents and food wastes. It coversminor pollution offences that were missed out of the EnvironmentalProtection Act 1986 (see above).

Specifically, is an offence to discharge sediment into the marineenvironment, and to discharge wastewater in which are: acid with apH less than 4; alkali with a pH more than 10; animal oil, fat orgrease; compounds of solutions of cyanide, chromium, cadmium,lead, arsenic, mercury, nickel, zinc, copper; degreaser; detergent;dye; engine coolant or engine corrosion inhibitor; mineral oil; organic

solvent; paint; petrol, diesel or other hydrocarbon; pesticide;vegetable oil, fat or grease.

Environmental Protection (ControlledWaste) Regulations 2004

DEC These regulations list the types of controlled waste which must bestored, treated, transported and disposed of as set out in theregulations. Controlled wastes relevant to the OPR wastemanagement include (but are not limited to) heavy metalcompounds, sewage, filter cake, acidic solutions, and waste fromthe use of organic solvents.

The DEC have developed a series of guidelines in support of theregulations for appropriate transport and disposal of controlledwaste:

Guideline for Controlled Waste Carriers (DEC, 2004a)

Guideline for Controlled Waste Treatment or Disposal Sites

(DEC, 2004b)

User Guide: Controlled Waste Tracking System (DEC, 2006)

Landfill Waste Classification and Waste Definitions(DEC, 1996).

W.A. Port Authorities Regulation 2001 W.A. Port Authorities The W.A. Port Authorities Regulation 2001 sets out rules for portuse applicable to all port authorities across Western Australia.Regulation 17 stipulates: Unless authorised by a member of staff ofthe port authority, the master of a vessel must not cause or permitany wastewater or waste substances of any kind to be dischargedfrom the vessel on to any part of the wharf or into the waters o f a

port.

Occupational Safety and Health Act 1984Department of Consumer and EmploymentProtection

Occupational Safety and Health

Western Australian Marine (SeaDumping) Act 1981

DEC Sea dumping

Ministerial Conditions

Ministerial Statement 469 (25 February1998) Conditions relevant to SedimentQuality.

Minister for the Environment and Youth Condition 1.1 requires commitments made by the proponent to befulfilled as part of implementing the proposal, the commitmentsmade in relation to Sediment Quality were as follows:


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Condition 5-3(5) requires the development of a Dredge and DredgeSpoil Disposal Management. Note: the Plans 5-3 (4) to 5-3 (11)have been formulated, based in part, on proponent commitment no.

6.

Consolidated List of Commitments (Attachment 1 to MS469)relevant to Marine Water Quality and Sediments states (Item #6):

The proponent will, prior to construction, prepare a MarineManagement Plan that will include the following:

6a. A Construction Management Plan in accordance with therequirements of the EPA, upon advice from the DEP. Allcontractors will be required to comply with this plan, which willspecify measures designed to prevent marine pollution and tolimit the impact on the marine environment;

6b. A Dredge and Dredge Spoil Disposal management Plan(DDSDMP) in the event that the final port plan involvesdredging. This Management Plan will be prepared inaccordance with the requirements of the EPA, upon advice

from the DEP, and will include a monitoring program for waterquality in and within a relevant distance of the works area. Themanagement plan and all results of the monitoring programswill be made available to the general public;

6c. An Oil Spill Contingency Plan to the satisfaction of theDepartment of Minerals and Energy, the EnvironmentalProtection Authority, the Department of EnvironmentalProtection, and the WA State Committee for Combating OilPollution at Sea. This plan will include managementprocesses required to avoid or minimise any impacts to thebeaches north of the port;

6d. A Waste Management Plan of port operations prepared inaccordance with the requirements of the EPA, upon advicefrom the DEP. This plan will specify management proceduresfor the collection and disposal of waste discharges from ships,

and will regulate wash-down of ships in harbour. This plan willinclude management processes required to avoid or minimiseany impacts to beaches north of the port, and will includetreatment of stormwater if appropriate;

6e. An accidental Spillage Management Plan to the requirements ofthe Department of Minerals and Energy. This Plan will includemanagement processes required to avoid or minimise anyimpacts to beaches north of the Port;

6f. A Water Quality Monitoring and Management Program inaccordance with the requirements of the EPA, upon advicefrom the DEP. A summary of the scope this monitoring isprovided in Section 6 of the PER document. Should levels ofany parameter be above the criteria during the samplingperiod, more frequent monitoring will occur in order to identifya possible cause for the elevated levels, and also to determinethe duration of the levels over time. Provision will be made toimplement appropriate management practices if the monitoringprogram identifies any unacceptable impacts on the quality ofmarine waters in the vicinity of the port; and

6g. A Sediment Monitoring and Management Program. This will beprepared in accordance with the requirements of the EPA,upon advice from the DEP. The program will involve bi-annualsamples following construction. All samples will be analysedfor a range of heavy metals and other potential contaminants.The results of the monitoring program will be provided to theEPA. Should levels of any parameters be above criteria during


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the sampling period, more frequent monitoring will occur toidentify a possible cause for the elevated levels, and also todetermine the duration of the levels over time. Provision will

be made to implement appropriate management practices ifthe monitoring program identifies any unacceptable impacts onthe quality of marine waters (assumed to have meantsediments) in the vicinity of the port.

The marine management plan will address the issue of protection ofoffshore seal colonies, and any other applicable protection issues.

Other Requirements

EPA Environmental AssessmentGuidelines 3 (EAG3) (EPA 2009)

OEPA

Provides a framework to impart clarity and consistency to theenvironmental impact of proposals that have potential to result inirreversible loss of, or serious damage to, benthic primary producerhabitats in Western Australia's marine environment.

Recognises the importance of Benthic Primary Producer Habitats

(BPPH) and the potential consequences of their loss for marineecological integrity, and also the fact that almost all marinedevelopment proposals will result in some loss of these importanthabitats.

OPR Environmental Management System(EMS)

OPR

Provides the framework for environmental management on theproject site in compliance with Australian Standards and NewZealand Standards (AS/NZS) International Standards Organisation(ISO) 14001:2004 Environmental Management Systems Requirements with Guidance for Use.

This EMP is managed via the OPR EMS

OPR has prepared separate management plans for each of the items listed under Section 6 of the Proponent's

Consolidated Commitment (MS469, Attachment 1) rather than a single Marine Management Plan. This is described inmore detail in Table 1-4 below.

The relationship between the environmental management system, the approvals for the various components of the overall

Oakajee development and these environmental management plans is shown in Figure 1.4 and Figure 1.5.


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Table 1.4: MS469 EMP Title and Proposed EMP submissions

MS 469

ConditionMS469 Title Proposed MP

5-3 (1) Rehabilitation and Coastal Management Plan Rehabilitation and Coastal Management Plan

5-3 (2)

Marine Flora and Fauna Management Plan to include: Marine Flora and Fauna Management Plan

- habitat description;- benthic surveys;

Dredging, Breakwater Construction and LandReclamation MP (this plan)

- marine mammal surveys (as it relates to underwater noise); Underwater Noise Management Plan

- wrack monitoring and management; Beach-cast Wrack Management Plan

- water quality monitoring Water Quality Monitoring and Management Plan

5-3 (3) Introduced Marine Organisms Management Plan: Introduced Marine Pest Management Plan

5-3 (4) Construction Management Plan Construction Management Plan

5-3 (5) Dredge and Dredge Spoil Management PlanDredge Breakwater Construction and Land Reclamation

MP (as above)

5-3 (6) Material Handling Environmental Requirements SpecificationMaterial Handling Environmental RequirementsSpecification

5-3 (7) Accidental Spillage Management Plan Accidental Spillage Management Plan

5-3 (8) Drainage Design and Treatment Management Plan Drainage Design and Treatment Management Plan

5-3 (9) Oil Spill Contingency Plan Oil Spill Contingency Plan

5-3 (10) Port Waste Management Plan Port Waste Management Plan

5-3 (11) Water and Sediment Quality Monitoring and Management PlanWater Quality Monitoring and MP (as above)Sediment Quality Management Plan

5-3 (12) Air Quality Management Plan Air Quality Management Plan

5-3 (13) Noise Management Plan Noise Management Plan

5-3 (14) Heritage Management Plan Heritage Management Plan

5-3 (15) Recreation Management Plan Recreation and Fishing Access Management Plan

7-1 Fishing Access Management Plan Recreation and Fishing Access MP(as above)

CC6

Coastal Stability Management Plan Coastal Stability Management Plan

6 CC - Consolidated Commitments 8 and 9 (Attachment 1 to MS 469) - see legislative and other requirement (Table 1-3)


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Figure 1.4: Project roadmap describing the environmental system and the relationship to the major areas of construction and environmental management programs


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1.5 Stakeholder Consultation

Ongoing stakeholder and community engagement is an important part of maintaining a community licence to operate.

That engagement should include open and transparent communication, and recognise the importance of genuine

stakeholder involvement in the identification of potential issues and concerns, as well as appropriate strategies for

management of impacts.

Stakeholders are defined as people or organisations who have an impact on, or who are impacted by project operations

and activities. An understanding of key stakeholder attitudes and issues is crucial to support effective stakeholder

engagement. Additionally the ability to demonstrably respond to community concerns is important. Initial consultation

was with the Environmental Protection Authority Service Unit (EPASU; now restructured to the Office of the EPA - OEPA)

(see Section 1.5.1 and Attachment A), followed by more extensive stakeholder consultation. A detailed description of

OPR stakeholder consultation is provided in Attachment B.

This DBCLRMP has been developed by recognised consultants and experts in the field and reviewed by various

government agencies (see Section 1.5.2). Furthermore, the design of baseline studies relevant to the Oakajee DeepwaterPort EMPs (Attachment C) was peer reviewed (see Section 1.5.1 below) by relevant field experts and the

outcomes/reports of those baselines studies were also peer reviewed.

1.5.1 Peer Review of Basel ine Studies

Project representatives, consultants and OEPA met on 9 December 2008 to discuss the present Oakajee Port proposal

and the need to commence field surveys and data acquisition tasks with long lead times. Following the meeting, the

Marine Ecosystem Branch of the OEPA provided some preliminary comments, which are summarised in Attachment A.

To ensure that the baseline studies were comprehensive and adopted rigorous sampling approaches, they were peer

reviewed by qualified professionals (Table 1.5). Reviewers comments and suggestions were incorporated into the

sampling methods for each of the studies.

Table 1.5: Summary of peer reviewers for the marine and coastal baseline studies

Reviewer Institute Position Studies Reviewed

Michael Mulligan Geraldton Port Authority - Port Environmental Coordinator All baseline studies

Dr Jim Stoddart MScience Principal Marine ScientistAll baseline studies (exceptcoastal processes)

Ian LeProvost URS Australia - Principal Environmental ScientistAll baseline studies

Dr Karen Hillman Oceanica Consulting - Director All baseline studies

Dr Julia Phillips CSIRO Marine Ecologist

Marine habitat

Curt Jenner Centre for Whale Research (WA) - Managing Director Marine mammals

Professor Chad HewittNational Centre for Coastal and Marine Conservation, AustralianMaritime College Chairman.

Introduced Marine Species

Jason Antenucci Centre for Water Research - Manager, Contract Research GroupValidation report forhydrodynamic modelling


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1.5.2 Collaborators

To ensure the highest standard of work, the development and implementation of the marine and coastal baseline studies

represents collaboration between Oceanica and various research institutes and marine and coastal specialists, as detailed

in Table 1.6.

Table 1.6: Summary of collaborators for the marine and coastal baseline studies

Collaborators Tasks

Asia Pacific Applied Science Associates(APASA)

Hydrodynamic modelling for the Oakajee Port

Batavia Coast Air Charter, Geraldton Provision of aeroplane and pilot for monthly aerial flight of Oakajee coastline forbeach cast wrack survey

Batavia Coast Maritime Institute (BCMI,Geraldton)

Provision of field personnel for the water quality and marine mammal surveys.Processing of seagrass, algal and wrack samples to determine healthcharacteristics (seagrass and algae) and composition (wrack)

Centre Marine Science and Technology CurtinUniversity (Rob McCauley)

Underwater noise modelling and interpretation of potential risks to marine faunain the Oakajee region

Centre for Whale Research (Curt JennerDirector)

Provision of specialist advice on the sampling of marine mammals within theOakajee region. Analysis of whale distribution and abundance data

Enviro Marine Consulting Pty Ltd (Alex Wyatt,Director); and

National Centre for Coastal and MarineConservation, Australian Maritime College(Marnie Campbell)

Provision of specialist advice on the sampling of introduced marine speciesaround the proposed location of the Oakajee port. Implementation of pre-construction sampling in the Oakajee region as per Hewitt and Martin protocols(see Hewitt & Martin 2001)

Global Environmental Modelling Systems(GEMS)

Hydrodynamic modelling for the Oakajee Port

Hille Thompson & Delfos, Surveyors & Planners(HTD)

Seasonal beach profiles for the coastal processes investigation

Latitude Fisheries, Geraldton Provision of research vessel for all marine surveys that require offshore work.

Marine and Freshwater Research Laboratory(MAFRL) - Murdoch University

Provision of specialist field assistance, equipment and laboratory analysis forthe water and sediment quality monitoring

Specialised Diving Services, Geraldton Provision of research vessel for all habitat mapping surveys and field personnelfor underwater diving

Two Fish Drowning, Geraldton Photography Capture of aerial photographs for monthly aerial flight of Oakajee coastline forbeach cast wrack survey

University of Western Australia (Professors GaryKendrick and Di Walker)

Advice on the method for developing benthic primary producer habitat maps.Interpretation of results and advice on determining the appropriate groups ofdominant primary producers.

Western Whale Research (Chris Burton,Director)

Provision of specialist advice on the sampling of marine mammals within theOakajee region. Analysis of whale distribution and abundance data

1.5.3 Peer Review of Draft EMP

The EPA was consulted with regard to the list of proposed EMPs to address the requirements of MS469. All EMPs

relevant to MS469 also require review and final approval by the EPA.

The draft EMPs were also reviewed by the various government agencies and consultants and comments incorporated as

per the table in Attachment B.


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2. EXISTING ENVIRONMENT

A description of the existing physical and biological marine environment surrounding the proposed port development was

provided as part of the environmental impact assessment process and was presented in the original Oakajee DeepwaterPort PER (AT & WEC 1997).

Following the PER, OPR completed extensive work in relation to marine and coastal baseline studies (refer to

Attachment 2 for the full list of marine studies) for the purpose of developing the construction and operational

environmental management plans (EMPs), to enable the Oakajee Deepwater Port to be implemented pursuant to MS469.

The following discussion on the existing environment is related to those aspects that are likely to be impacted by dredging,

breakwater construction and land reclamation during the proposed port construction.

2.1 BPPH Mapping

The benthic habitat at Oakajee was first described in detail during the Oakajee Deepwater Port PER (AT & WEC 1997).

This study mapped benthic habitat in terms of the dominant substrate types, including; beach, shallow sand, high reef, amixture of shallow pavement, low reef and shallow sand, and a mixture of deep pavement and deep sand. Most recently

BPPH in the vicinity of the proposed Oakajee Deepwater Port was further surveyed to map the spatial distribution of the

dominant BPPH groups in greater detail (Oceanica, 2008). The area mapped has a footprint of ~57 km2, which was

agreed with the OEPA to be the local assessment unit (LAU) in accordance with Environmental Assessment Guideline 3

(EAG3) (EPA 2009). The area includes the coastal marine environment ~11 km to the north and south of the port, and

extending ~2.5 km to 3.5 km offshore to the 20 m depth contour(Figure 2.1).

The BPPH at Oakajee are similar to and generally representative of BPPH on the west coast of Western Australia

(Kirkman, 1997). The dominant primary producers are algae, of which robust brown (including Ecklonia sp.) and foliose

brown algae appear to be most prevalent (Oceanica 2008). The dominant seagrass is from the genusAmphibolis, which

is endemic to temperate western and southern Australian coastal areas (Ducker et al., 1977). The other major seagrass

present in the region is Thalassodendron pachyrhizum, which has a distribution from the Abrolhos Islands south to Bremer

Bay, Western Australia (Huisman, 2000). As reported by other workers (AT& WEC, 1997; LDM, 1999; Van Keulen et al.,

1998) the BPPH at Oakajee is best described as being extremely heterogeneous, characterised by a complex mosaic of

habitats, which change considerably over the space of a few metres, particularly in the shallow inshore waters and the

high relief reef (LDM, 1999).

2.2 BPPH Health

A marine habitat monitoring survey was conducted to provide background habitat data for a Before-After-Control-Impact

(BACI) assessment, with sufficient rigour to separate change associated with natural variation from change that can be

reasonably attributed to anthropogenic impacts, such as dredging (Oceanica, 2010). The monitoring program was

designed to assess changes in seagrass health characteristics in space (reference areas versus areas with potential forport construction impacts) and time (inter annual variability, rather than seasonal variability). The study assessed three

years of baseline data from seagrass surveys and two years baseline data from an algal survey using several different

physiological indicators. Differences between potential impact areas and reference areas were detected for 3 of the 28

parameters that were measured. The study also revealed that some of the habitats in the potential impact areas were

naturally different from the reference areas, before port construction. Twelve of the 28 seagrass and algal characteristics

were found to differ significantly among reference areas. The differences detected among the reference areas reflect

natural spatial and temporal variation occurring in the system. Five of the 28 seagrass and algal characteristics were


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found to differ significantly from year to year, which may be associated with broad-scale oceanographic or climatic

processes.

2.3 Water Quality

The baseline water quality of the Oakajee region was characterised seasonally for the period 2006-2009 (Oceanica 2008a

and Oceanica 2009). Considerable spatial and temporal variation was apparent for the majority of water quality

parameters at Oakajee. Spatial variation existed between the majority of sites reflecting the patchy and heterogeneous

nature of conditions in the Oakajee region. Such variation is common for such an exposed and highly dynamic coastline.

Comparison of the water quality data at Oakajee with the Australia and New Zealand Environment Conservation Council

ANZECC and Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ) (2000) default

water quality guidelines revealed that some of the measured baseline conditions at Oakajee were naturally higher than the

guideline levels. Such exceedances were most common for nutrients and chlorophyll a in the inshore environment, and

were occasionally observed at midshore and offshore sites. Turbidity and light attenuation measures at midshore and

offshore sites were also above the ANZECC and ARMCANZ (2000) guideline range in all seasons. Nutrient exceedances

in inshore waters may reflect the contribution from wrack accumulation and decomposition (Oceanica, 2009), whileturbidity and light attenuation exceedances are likely to be indicative of the highly exposed and dynamic conditions at

Oakajee, creating a naturally more turbid environment.

2.4 Sediment Quality

The baseline sediment investigations of the Oakajee region tested for the presence of natural and anthropogenic

contaminants (Oceanica 2009a, b, c and d) in accordance with methods defined by the National Water Quality Strategy

(ANZEEC and ARMCANZ 2000), the Contaminated Sites Guideline Series (DoE 2003), and the National Assessment

Guidelines for Dredging (CA 2009). Both the surface sandy sediments and the consolidated rocky sediments were

screened for natural and anthropogenic contamination. The screening included: metals, hydrocarbons and acid sulphate

soils in the consolidated sediments; and, metals, pesticides and organotins in the unconsolidated sediments. All of the

sediments tested returned results below guideline levels, which included: the Ecological Investigation Level (EIL) for afirst pass assessment (DoE, 2003); and, the National Assessment Guidelines for Dredging (CA, 2009). Consequently,

the proposed dredge material was compliant in relation to both ocean disposal and land reclamation activities (Oceanica

2009c; Oceanica 2009d).

2.5 Wind, Currents, Waves and Tide Conditions

The meteorological and oceanographic conditions for the Oakajee region are described in detail in APASA (2009a) and

Oceanica (2007) reports.

A general description of the wind speed and strength was obtained from the Bureau of Meteorology (BOM;

www.bom.gov.au). The wind strength and direction exhibited a strong diurnal pattern. The dominant wind directions in

the mornings were from the NE and E (Figure 2.2), whereas during the afternoon the winds were primarily from the S andSW (Figure 2.2). The summer wind pattern was dominated by S and SE winds in the morning and S and SW sea breezes

in the afternoon. Autumn directions were relatively light and variable in the mornings, and were generally from the S and

SW in the afternoon. During winter, winds were mostly from the NE in the morning, whereas speeds generally increased

in the afternoons with strong sea breezes from the S and SW. Spring wind directions were generally from the south, with

a greater E component in the morning and W component in the afternoon. The greatest wind speeds were observed in

the winter and the summer with the maximum speeds recorded in the summer during most years.
http://www.bom.gov.au/http://www.bom.gov.au/http://www.bom.gov.au/


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Figure 2.1: Benthic primary producer habitat map of the Oakajee region


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Figure 2.2: Wind frequency analysis (wind roses) from the Geraldton Airport (9am and 3pm)


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Current measurements from the Oakajee 20m AWACstation indicate that there is a significant difference in the dominant

current direction when comparing the near-seabed measurements to those made closer to the surface. Measurements

from the mid-depth and near surface meters, indicate that currents head in the NW direction approximately 35% and 45%

of the time. This is also the direction where the strongest currents occur, with currents over 0.25 m/s occurring forapproximately 73% of the time in the NW direction. Similarly, at mid-depth, of the currents over 0.25 m/s approximately

45% occur in the NW direction. Near seabed currents, on the other hand, show an almost equal distribution in current

direction in the N, NW, W and SW directions, with current magnitudes consistently spread over these directions.

Seasonal variations at the Oakajee 20m AWACnear-surface and mid-depths, indicate that summer and spring show a

similar dominance of currents heading NW. In contrast, autumn and winter show a transition to more S and SE directed

currents; however the strongest currents still occur in the W to NW directions.

Analysis of ADCP data measured between 7 June 2006 to 10 January 2007 and 23 November 2007 to 25 July 2008

showed that wave heights were


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3. POTENTIAL IMPACTS

The potential impacts outlined below are those may be expected from dredging, breakwater construction and land

reclamation activities associated with the construction of Oakajee Port. For clarity, the main focus of each subsection is

summarised below:

Method

o Outlines the method for identifying and managing potential marine environmental impacts from dredging,

breakwater construction and land reclamation activities.

Impacts

o Provides a list of the environmental aspects, potential impacts and impact pathways from dredging,

breakwater construction and land reclamation activities.

Hydrodynamic modelling of impacts to BPPH

o Provides information on the methods and results of hydrodynamic modelling;

o Provides loss calculations for indirect BPPH losses due to construction sedimentation; and,o Provides loss calculations for indirect BPPH losses due to a reduction in saturating light.

Infrastructure footprint impacts to BPPH

o Outlines the expected losses from the direct impact of port infrastructure on BPPH.

Water quality impacts

o Provides information on the potential impacts to the water quality of the receiving marine environment from

land reclamation return water.

3.1 Method

This EMP was developed on the basis of the Ministerial Conditions and the project's Environmental Risk Register. The

register was developed using the IMS-SF-1 Environmental Risk Register Template and in accordance with the IMS-SP-1

Environmental Risk Management Procedure. The risk evaluation is based on the overall project risk managementprinciples based on AS/NZS 4360: Risk Management.

The management of impacts associated with the Project activities are based on a risk management framework aligned to

ISO 31000:2009 Risk Management. This involves:

Identification of key activities that may interact with the project environment;

Implementing controls to reduce risk and severity of impacts; and,

Monitoring the effectiveness of controls.

A risk assessment of activities and potential impacts of the Project was conducted within the risk management framework

to create a Risk Register.

The key project activities of the proposal were identified. The events that may cause impacts to the environment were

determined, and their associated potential impacts listed.

The risk of the impacts occurring was analysed by determining the consequence severity of the impacts and the likelihood

of consequences being realised. The severity of the consequences was determined using a Consequence Severity

Table. The likelihood of an impact resulting from a pathway was determined with a Likelihood Ranking Table. The level

of risk was determined using a Risk Matrix, which determines the overall level of risk.


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To prevent or minimise the impacts, controls are placed on the pathways in this order of hierarchy of control principles:

Elimination of the activity;

Substitution with a lower risk activity or product;

Engineeringsolutions to reduce the impact of the event;

Implementation ofadministrative procedures to control the activity; and,

Clean up or remediation measures to mitigate impacts after an event.

Performance indicators are selected parameters that provide indications of the effectiveness of the management

strategies. These indicators have been translated to performance targets.

3.2 Impacts

Port construction, including dredging, breakwater construction and land reclamation will cause the development of turbid

sediment plumes that could potentially cause adverse impacts on the marine environment.

Return water from the land reclamation areas may potentially have different temperature, salinity and pH, than the

receiving natural environment, which may impact the environmental values of the area immediately surrounding the point

of water return to the receiving environment.

The major pathways potentially causing turbidity and a change to the physico-chemical water quality are listed below:

Dredged materials7, including beach sand and consolidated rock, which may release suspended sediments into themarine environment during dredging of the port berths, turning basin and shipping channel;

Dredged materials used in the land reclamation area, which may result in the release of suspended sediments intothe marine environment;

Return water from the reclamation area, which may change the physico-chemical water quality adjacent to the port;and,

Dust and dirt from the breakwater rock armour and core material, which may release suspended into the marineenvironment during breakwater construction.

The three major types of construction activity, including dredging, breakwater construction and land reclamation have the

potential to cause impact the marine environment through different pathways (Table 3.1).

The predicted losses of marine habitat attributable to dredging, breakwater construction and land reclamation are provided

in Table 3.2. These predictions indicate that the total impact from the port footprint will result in losses of 146.2 ha

(Figure 3.1), which complies with the MS469 requirement that not more than 170 ha of habitat should be destroyed.

Additionally, no individual habitat type has a cumulative loss of more than 10% of the local assessment unit (5690 ha at

Oakajee), which is in accordance with Category E (development areas) as outlined in EAG3 (EPA 2009). Expected BPPH

losses associated with dredging, breakwater construction and land reclamation are shown in Table 3.3 and Figure 3.2.

7 Screening of the unconsolidated (sandy) sediments and consolidated (rock) sediments for potential contamination did not reveal any

naturally occurring contamination above screening levels at the port development site (Oceanica 2009a Oceanica 2009b).


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Table 3.1: Construction activity, pathway, environmental impact

EnvironmentalAspect

Potential impact Potential Impact Pathway EPA EnvironmentalValue

Relevant EMP

Dredging

BPPH Indirect impact to BPPH Sediment Plume - Reduction in the amount oflight reaching BPPH

Ecosystem health DBCLRMP

BPPH Direct impact to BPPH Sediment Plume Smothering of BPPH bysediment as it settles out of the water column


BPPH Direct impact to BPPH Dredge footprint Destruction of BPPH bythe dredge outside the proposed area


IntroducedMarineOrganisms

Introduction of Marine Pests may cause ashift in species composition and ecosystemprocesses

Inoculation from dredge and associatedvessels caused by inadequate quarantinepractices

Ecosystem health IMPMP

Marine Fauna Disruption or injury to cetaceans and othermarine fauna

Noise from dredge Ecosystem health UNMP

Marine Fauna Injury or death to cetaceans and other marinefauna

Vessel strikes Ecosystem health MFFMP

Water Quality Intermittent reduction in visibility for durationof the dredge program

Sediment plume from dredge cutter head Recreation andaesthetics

DBCLRMP

Water Quality Contamination of the marine environment,potential impact on ecology, and commercialand recreational fishery

Refuelling, hydrocarbon handling, lubricationof dredge cutter head

-Ecosystem health

-Fishing

-Recreation andaesthetics

OSCP

Breakwater Construction

BPPH Indirect impact to BPPH Sediment Plume from fine particulate materialon construction material and disturbance ofmarine sediments - Reduction in the amountof light reaching BPPH


BPPH Direct impact to BPPH Sediment Plume Smothering of BPPH bysediment as it settles out of the water column


BPPH Direct impact to BPPH Breakwater footprint - Destruction of BPPH bybreakwater construction outside the proposedarea


IntroducedMarineOrganisms

Introduction of Marine Pests may cause ashift in species composition and ecosystemprocesses

Inoculation from dredges and bargescaused by inadequate quarantine practices

Ecosystem health IMPMP

Marine Fauna Disruption or injury to cetaceans and othermarine fauna

Noise from pile driving Ecosystem health UNMP

Water Quality Intermittent reduction in visibility for durationof the breakwater construction program

Sediment plume from breakwaterconstruction material may reduce water clarity

Recreation andaesthetics

DBCLRMP

Beach-castWrack (WaterQuality)

Accumulation of beach cast wrack againstbreakwater

Decomposing beach-cast wrack may alter thedistribution of nutrients in the region, mayproduce unpleasant odour and impact thevisual amenity.

Ecosystem health


BWMP

ShorelineStability

Erosion or accretion of beaches in closeproximity to the port

Breakwater construction may alter watercirculation patterns

Ecosystem health SSMP


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EnvironmentalAspect

Potential impact Potential Impact Pathway EPA EnvironmentalValue

Relevant EMP

Land Reclamation

BPPH Indirect impact to BPPH Sediment Plume from the discharge of returnwater from land reclamation containing fineparticulate material- Reduction in the amountof light reaching BPPH


BPPH Direct impact to BPPH Sediment Plume Smothering of BPPH bysediment as it settles out from return-waterdischarge


BPPH Direct impact to BPPH Land reclamation footprint Destruction ofBPPH by land reclamation footprint outside theproposed area


Water Quality Intermittent reduction in visibility for durationof the return-water flow

Sediment plume from land reclamation return-water material, which may reduce water clarity


DBCLRMP

Table 3.2 : Summary of the total area of marine habitat impacts impacted from port construction,

including port infrastructure footprint and indirect impacts to BPPH

Cause of impact Area of impact (ha)

Breakwater 26.8

Breakwater halo 13.9

Dredge 69.0

Reclamation 26.3#Sedimentation impact on BPPH -model output 6.9

#Indirect impact on BPPH (reduction in saturating light) - model output 3.3

Total 146.2

# BPPH losses do not include areas bare sand habitat

Table 3.3: Summary of BPPH categories and losses attributable to port construction

#HabitatType

Hsat impact- Modelled

Sedimentation- Modelled

Dredgefootprint

Breakwaterfootprint

BreakwaterHalo

Total

*Percentageof habitat

loss

Sand withseagrass

0.2 0 3.2 0 0 3.4 0.06%

Reef withalgae

0 0.8 11.0 4.9 0.8 17.5 0.31%

Reef withalgae andseagrass

3.0 0.7 31.5 9.7 6.8 51.7 0.91%

Inshore reefwith algae

0.1 5.4 4.3 0.6 6.1 23.5 0.41%

3.3 6.9 50.0 15.2 13.7 96.1 1.69%

# BPPH losses do not include areas bare sand habitat

* habitat losses should not include port infrastructure for assessment purposes according to EAG3 (EPA 2009)


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Figure 3.1: Total area of marine habitat impacted from port construction, including port infrastructure footprint,indirect impact to BPPH from reduced light, and direct BPPH impact from sedimentation. Note that the

sedimentation impacts to the south are attributable to southern land reclamation return water


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Figure 3.2: BPPH losses from port construction attributable to sedimentation and reduced light attenuation


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3.3 Hydrodynamic modelling of BPPH impacts

3.3.1 BPPH loss predictions

To examine the environmental impacts associated with sediment plumes expected to be generated during construction ofthe Oakajee Deepwater Port, hydrodynamic modelling was undertaken by Asia-Pacific Applied Science Associates

(APASA). The description below provides a summary of the modelling conducted for the proposed port construction. For

a more detailed account of the methods, scenarios and limitations of the modelling refer to the following documents:

Oceanica and APASA (2010a) (Attachment D);

APASA (2009); and,

APASA (2009a).

The APASA modelling was conducted in two phases. Phase 1 involved modelling the fate of suspended sediment

material deposited into the marine environment during the construction of the port breakwater. Phase 2 involved dredge

dispersion modelling for the duration of all the dredging operations associated with the development. The methodsemployed in the modelling are provided in detail in APASA (2009).

A supplementary report was developed to interpret the predictive (numerical) modelling results from port construction and

use those data to assess the potential impact of turbidity and sedimentation on benthic primary producer habitat

(Oceanica and APASA 2010a). Specifically, the report described the zones of impact on benthic primary producer habitat

resulting from the predicted the turbidity plume generated by construction activity over the construction period. Benthic

primary producer habitat in the Oakajee Deepwater Port region comprise algae as well as seagrass, but as seagrass was

considered the benthic primary producer most sensitive to turbidity, the predicted effects on seagrass (Amphibolis griffithii)

health were used to conservatively define potential areas of impact on all benthic primary producers. Furthermore, an

estimate of the potential loss from bottom deposition of sediment over the model domain was made.

The APASA modelling was undertaken to quantify the movement of suspended sediment generated during construction of

the proposed Oakajee Deepwater Port Development, and incorporated physical data collected from the Oakajee region.

The study involved using Lagrangian particle tracking models to track the fate of the sediment using forcing conditions

specified by a wave model and three-dimensional, numerical, hydrodynamic model. The models enabled the sediment

dispersal patterns to be calculated under a range of forcing conditions, and for different construction scenarios. The

domain of the study was sufficient to encompass the total area affected by the sediment plumes arising from the proposed

dredging and disposal operations, to a distance where the concentrations might be significant. The total area affected

included the initial extent of the sediment plume and deposition and areas affected following the reworking of sediments,

which occurs through re-suspension and subsequent transport. The domain of the study was large enough to capture the

forcing effects of all relevant sediment transport mechanisms over the study area. In particular the effect of wind energy

transfer to the sea surface over long fetches of the order of 10s km was important for both wave and current generation.

The sediment transport model also accounted for particle-size specific sinking, sedimentation and re-suspension of

sediments for the range of current and wave conditions as derived by the hydrodynamic and wave models. The model

also accounted for the effects of sediment cohesion (i.e. clumping) on sinking rates of fine particles and the effects of

sedimentation history, burial and armouring on re-suspension rates. The sediment model also represents cumulative

effects of multiple sources of suspended sediment over and beyond the duration of the full construction program (i.e.

36 months) in order to quantify the time-history of effects and the full footprint of the operation. All of these requirements

were considered in developing optimal models for this study.


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The model was developed using four likely scenarios of meteorological and oceanographic conditions, which included:

1. Low total suspended solid (TSS) concentration (100 mg L-1

) from land reclamation return-water and La Nia climaticconditions;

2. High TSS concentration (250 mg L-1) from land reclamation return-water and La Nia climatic conditions;

3. Low (TSS) concentration (100 mg L-1) from land reclamation return-water and El Nio climatic conditions; and,

4. High TSS concentration (250 mg L-1) from land reclamation return-water and El Nio climatic conditions.

La Nia and El Nio climatic conditions were both modelled because the transition between autumn and spring showed

distinct inter-annual variation depending on whether a particular year was more summer like with winds from the south,

or more winter like with winds from the north-east. Winter like winds corresponded to weak La Nia years, whereas

summer like winds were related to weak El Nio years (APASA 2009). In order to capture the effects of inter-annual

variability, both cases were considered in the modelling.

The selection of TSS concentrations was based on results from other capital dredging projects in Western Australia. In

particular, data from a dredging program where the dredge material was collected in a bunded reclamation area had

return water with a measurable TSS of ~100 mg L -1 (confidential data). Based on these data, the selection of 250 mg L-1

was considered a highly conservative estimate and a worst-case scenario.

Estimates of the area impacted by the modelled turbidity plume were based on seagrass light criteria described by the

parameter Hsat, which describes the decrease in hours of saturating irradiance of seagrass in shaded (impact) areas

versus control (reference) areas. The impact on seagrass was expressed as the percentage reduction in the above

ground biomass (leaves and stems) of seagrass in the impact site compared with the reference site. These parameters

were based on an established study conducted at Jurien Bay, some 200 km south of the Oakajee Port site

(Lavery et. al. 2009). For a full description of the methods employed to develop the Hsat light criteria, refer toAttachment D.

Zones of high impact, moderate impact and low impact were determined for the Oakajee development site for each of the

model scenarios. Of the four scenarios, the worst-case in terms of impacts on the light environment (i.e. shading) was the

high TSS concentration (250 mg L-1) from land reclamation return-water and La Nia climatic conditions. Note that due to

the close proximity of the three areas of impact described above and the relatively small combined total footprint, these

will be considered together in the loss calculations at the Zone of Impact (ZoI) (Table 3.4). The predicted area of the ZoI

is shown in Figure 3.2, which provides a good estimate of the potential area of impact based on the physical

oceanographic parameters used in the model. However, it is likely that the actual oceanographic conditions will vary from

the modelled conditions during construction so that the actual footprint location may differ to that predicted by the model.

Considering this, the predicted area of impact (10.2 ha, see Section 3.4), will be assessed within a moderate ecological

protection area (MEPA, see section Section 3.4 for the MEPA boundary).

An estimate of the area of BPPH lost by sediment burial was also made using APASA (2009

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