Rumah Baru Freight and Passenger Facilities, Cocos (Keeling ...

Rumah Baru Freight and Passenger Facilities, Cocos (Keeling) Islands Construction Environmental Management Plan May 2009

P:\VDMGroup\782_RumahBaruEMP\001_CEMP\Reports\CEMP\CEMP\FINAL_CEMP_REV02_20090511.doc

Rumah Baru Freight and Passenger Facilities, Cocos (Keeling) Islands

Construction Environmental Management Plan

Prepared for

Wylie & Skene

Prepared by

Oceanica Consulting Pty Ltd

May 2009

Report No 782_001/1

Oceanica: Wyllie & Skene: Rumah Baru Freight and Passenger Facilities, Construction Environmental Management Plan i

Contents

Rumah Baru Freight and Passenger Facilities, Cocos (Keeling) Islands ...........3

Construction Environmental Management Plan...........................................................3

Prepared for ...............................................................................................................................3

Wylie & Skene ...........................................................................................................................3

Prepared by ................................................................................................................................3

Oceanica Consulting Pty Ltd ................................................................................................3

Client: Wylie & Skene............................................................................................................5

Revisions history......................................................................................................................5

Status ...........................................................................................................................................5

Disclaimer ...................................................................................................................................5

Copying this report without the permission of Wylie & Skene or Oceanica Consulting Pty Ltd is not permitted.....................................................5

Cover.............................................................................................................................................5

Contents .......................................................................................................................................i

List of Tables ............................................................................................................................iv

List of Figures...........................................................................................................................iv

List of Appendices ...................................................................................................................v

1. Introduction......................................................................................................................1 1.1. Communications and management hierarchy....................................................... 1 1.2. Relevant documents ........................................................................................................ 1 1.3. Purpose of the construction environmental management plan..................... 1 1.4. Stakeholder consultation............................................................................................... 2 1.5. Relevant legislation ......................................................................................................... 2

2. Project Description ........................................................................................................4 2.1. Project description and location ................................................................................. 4 2.2. Construction methods ..................................................................................................... 6

2.2.1. Temporary boat ramp ............................................................................................. 6 2.2.2. Stilling basin construction ...................................................................................... 9 2.2.3. Access bridge and temporary access corridor ................................................. 12 2.2.4. Sheet piling for land reclamation boundary ..................................................... 12 2.2.5. Dredging and dredge spoil management.......................................................... 14 2.2.6. Land reclamation – offshore island .................................................................... 15

2.3. Construction schedule .................................................................................................. 18

ii Oceanica: Wyllie & Skene: Rumah Baru Freight and Passenger Facilities, Construction Environmental Management Plan

3. Management commitments ......................................................................................21 3.1. General induction ........................................................................................................... 21

3.1.1. Management Objective......................................................................................... 21 3.1.2. Performance indicators: ....................................................................................... 21 3.1.3. Induction requirements ........................................................................................ 21 3.1.4. Corrective Actions.................................................................................................. 21

3.2. Marine Flora and Fauna................................................................................................ 21 3.2.1. Management Objective......................................................................................... 21 3.2.2. Performance Indicators ........................................................................................ 22 3.2.3. Potential impacts ................................................................................................... 22

The proposed management approaches to avoid environmental impacts are outlined in................................................................................................................22

3.2.4. Turtle Exclusion Device ........................................................................................ 22 3.2.5. Silt Curtains ............................................................................................................ 23 3.2.6. Noise and vibration impacts to turtles .............................................................. 24

3.3. Terrestrial Flora and Fauna ........................................................................................ 29 3.4. Terrestrial Water Quality Management ................................................................. 29 3.5. Traffic and Disturbance to the Population ........................................................... 30 3.6. Noise and vibration........................................................................................................ 30 3.7. Rehabilitation and Visual Environment ................................................................. 31 3.8. Quarantine......................................................................................................................... 31 3.9. Archaeology and Heritage........................................................................................... 32 3.10. Construction Waste Management ............................................................................ 32 3.11. Pollution Control during Construction and Operation ..................................... 33 3.12. Emergency Response at Construction and Operation ..................................... 34

4. Review Procedure ........................................................................................................35 4.1. Reporting requirements............................................................................................... 35

5. Baseline monitoring ....................................................................................................36 5.1. Baseline survey ............................................................................................................... 36

6. Dredge Management Plan .........................................................................................37 6.1. Water quality management parameters ............................................................... 37

6.1.1. Introduction ............................................................................................................ 37 6.1.2. Monitoring parameters ......................................................................................... 37 6.1.3. Plume characteristics ............................................................................................ 38 6.1.4. Atmospheric and oceanographic measurements ............................................ 38 6.1.5. Water quality parameters .................................................................................... 40

6.2. Water quality monitoring programme ................................................................... 42 6.2.1. Management framework ...................................................................................... 42

All monitoring results will be reported on a weekly basis to the site superintendent. .............................................................................................................42

6.2.2. Coral monitoring .................................................................................................... 43 6.2.3. Seagrass monitoring ............................................................................................. 45 6.2.4. Turbidity trigger level review .............................................................................. 49

Oceanica: Wyllie & Skene: Rumah Baru Freight and Passenger Facilities, Construction Environmental Management Plan iii

6.3. Mitigation and management measures.................................................................. 50 6.3.1. Dredging .................................................................................................................. 50

Stop dredging ..........................................................................................................................50 6.3.2. Stilling pond return water .................................................................................... 50 6.3.3. Land reclamation ................................................................................................... 51 6.3.4. Filling of geotextile tubes and bags ................................................................... 51 6.3.5. General review of methods.................................................................................. 51

6.4. Monitoring of biota ......................................................................................................... 51 6.4.1. Objective.................................................................................................................. 51 6.4.2. Coral Monitoring ..................................................................................................... 52 6.4.3. Seagrass/macroalgae Monitoring ....................................................................... 54

6.5. Coral Spawning Monitoring......................................................................................... 57 6.5.1. Background ............................................................................................................. 57 6.5.2. Methodology of anticipation of coral spawning ............................................... 57

Table 6.7 Predicted coral spawning and observation dates ................................58

7. Removal of coral bommies........................................................................................59 7.1. Bommies for removal .................................................................................................... 59 7.2. Methodology for removing the bommies .............................................................. 59

8. Environment team ........................................................................................................61 8.1. CEMP and monitoring .................................................................................................... 61

9. References.......................................................................................................................62

Dr Rick Morton, Port of Brisbane .....................................................................................65

iv Oceanica: Wyllie & Skene: Rumah Baru Freight and Passenger Facilities, Construction Environmental Management Plan

List of Tables Table 1.1 Legislation relevant to the Rumah Baru passenger terminal project................ 2 Table 2.1 Current and target depths for the dredge programme ................................ 14 Table 2.2 Draft schedule for the onsite construction (as of March 10, 2009), subject

to approval by the Superintendant .......................................................... 19 Table 2.3 Draft schedule for main components of dredging and other turbidity

generating works, 2009......................................................................... 20 Table 3.1 Management approaches for the protection of marine flora and fauna

during construction ............................................................................... 27 Table 3.2 Emergency Contact Telephone Numbers for the Cocos (Keeling) Islands ....... 34 Table 6.1 Beaufort wind and sea state scale, as modified by AIMS for the long-term

monitoring programme.......................................................................... 40 Table 6.2 Logger specifications ............................................................................. 41 Table 6.3 Coral turbidity trigger levels and sedimentation thresholds and action

criteria ................................................................................................ 44 Table 6.4 Seagrass turbidity trigger levels and light thresholds and action criteria........ 48 Table 6.5 Back-up thresholds for Thalassia hemprichii at Rumah Baru based on

turbidity and Secchi in event that light loggers fail..................................... 48 Table 6.6 Indicative sampling locations for corals (‘c’) and seagrass (‘s’).

Coordinates are given in UTM47 GDA94 ................................................... 54 Table 6.7 Predicted coral spawning and observation dates ........................................ 58

List of Figures Figure 1.1 Communications and management hierarchy.............................................. 1 Figure 2.1 Location of the marine footprint of the Passenger Terminal at Rumah Baru

on West Island, Cocos (Keeling) Islands..................................................... 5 Figure 2.2 Rumah Baru passenger facility footprint, location of the current boat

ramp, and position of the temporary boat ramp (circled in blue).................... 7 Figure 2.3 Layout of the temporary boat ramp north of Rumah Baru. ............................ 8 Figure 2.4 Flexmat installed for recreational boat ramp ............................................... 9 Figure 2.5 Stilling basin ........................................................................................ 11 Figure 2.6 Sheet piling along part of the land reclamation. ........................................ 13 Figure 2.7 Amphibian Dredger ............................................................................... 15 Figure 2.8 Position of geotextile tubes for the creation of the seawall. ......................... 17 Figure 2.9 Geotextile material (left) and filled geotextile tubes (right) ......................... 18 Figure 3.1 Turtle exclusion devices fitted to TSD drag heads: chains (left) and plough

(right) (Morton, 2007-Appendix A) .......................................................... 23 Figure 6.1 Monitoring, mitigation and management framework for turbidity creating

activities ............................................................................................. 43 Figure 6.2 Proposed water quality monitoring programme for coral ............................. 45 Figure 6.3 Proposed water quality monitoring programme for seagrass........................ 47 Figure 6.4 Relationship used to derive interim Secchi Disk threshold from light

attenuation (Kd) ................................................................................... 49 Figure 6.5 Relationship used to derive interim turbidity threshold from light

attenuation (Kd) ................................................................................... 49 Figure 6.6 Location of coral bommies, including inside the proposed approach

channel (GHD, 2008a)........................................................................... 53 Figure 6.7 Proposed monitoring and reference sites for corals .................................... 55

Oceanica: Wyllie & Skene: Rumah Baru Freight and Passenger Facilities, Construction Environmental Management Plan v

Figure 6.8 Proposed monitoring and reference sites for seagrass ................................ 56 Figure 7.1 Location of bommies proposed for removal prior to dredging....................... 60

List of Appendices Appendix A “Marine Fauna and Dredging” Appendix B Silt Curtains as a Dredging Project Management Practice Appendix C Silt Curtain Specifications Appendix D Daily Recording Sheets Appendix E Baseline Survey 2009 Appendix F CVs of the environmental team

Oceanica: Wyllie & Skene: Rumah Baru Freight and Passenger Facilities, Construction Environmental Management Plan 1

1. Introduction

1.1. Communications and management hierarchy The communications and management hierarchy for the Rumah Baru development is shown in Figure 1.1. The way the client has structured the contract, means that the contractor’s environmental consultant is only engaged to take direction from the contractor and not the client’s supervisor or the client. This means that the client supervisor must provide completely clear, unequivocal instructions to the contractor on all matters pertaining to the environment.

Figure 1.1 Communications and management hierarchy

1.2. Relevant documents Relevant documents for the Rumah Baru Freight and Passenger Terminal are: • Construction Environmental Management Plan (CEMP) – contains the specific

management strategies for avoiding and mitigating construction impacts (this document) • Environmental Management Plan (EMP) – contains the framework for avoiding and

mitigating construction impacts (GHD, 2008a) • Specification for Rumah Baru, Cocos (Keeling) Islands Freight and Passenger Facilities –

contains contract specifications and construction requirements (GHD, 2008b) • Notice of Intent (NOI) – contains the environmental impact assessment (GHD, 2000)

1.3. Purpose of the construction environmental management plan The purpose of the CEMP is to define the specific monitoring and management commitments to be undertaken by Wylie & Skene in response to comments provided by DEWHA on the EMP. The CEMP has been prepared to ensure that any environmental impacts which may occur during the construction of the facility are minimised and managed. This CEMP provides all project personnel and contractors with information about their specific environmental commitments and management of the potential environmental impacts associated with the construction of the Rumah Baru Passenger Terminal. This CEMP: • Provides a description of the proposed works; • Examines and assesses the environmental risks and effects of the development, as listed

in the EMP (GHD, 2008a); • Describes the environmental monitoring which will be conducted prior to and during

construction; and • Presents environmental management and mitigation strategies addressing environmental

risks and effects.

2 Oceanica: Wyllie & Skene: Rumah Baru Freight and Passenger Facilities, Construction Environmental Management Plan

1.4. Stakeholder consultation There has been extensive community consultation during the planning and design phases of the project. Stakeholders consulted included: • The former Cocos (Keeling) Islands Administration; • The Shire of Cocos (Keeling) Islands (SCKI); and • Various business operations on Cocos (Keeling) Islands; and • The community on Cocos (Keeling) Islands. The objectives of the community consultation program included: • To communicate to the local community the need to improve the current passenger and

freight handling systems; • To providing a mechanism to receive community comments and ideas on freight handling

and passenger facilities; • To address sensitive issues for the local community including the requirement for the

West Island Jetty after the construction of Rumah Baru. The community consultation process has made sure that clear and concise information is available so that the community understands the opportunities and constraints of the development. The two-way transfer of information has taken place through a range of mediums including permanent public displays and community meetings. Provisions were made to enable members of the community to respond and provide feedback in a range of ways. The feedback from the community has indicated significant support for improved freight and passenger facilities. The following summarises feedback from the community. • The respondents were enthusiastic about the proposed facilities and that the development

would improve freight transport and ferry services; • All respondents considered that Rumah Baru is the most appropriate location for the new

facilities; • Most of the respondents had experienced problems and safety concerns with existing

facilities (freight and ferry delays due to weather); and • Most of the respondents indicated that they consider the new facilities would have a

positive impact upon themselves and the Cocos (Keeling) Islands. Consultation regarding the potential design, construction and operational impacts of the development will be ongoing and continue through the preconstruction, construction and management phases as necessary. Prior to construction the Superintendent shall issue the key stakeholders’ contact details to Wylie & Skene. It will then be the responsibility of Wylie & Skene to correspond with the Stakeholders prior to, during and on completion of construction with regards to any issues that the Stakeholders may have.

1.5. Relevant legislation The environmental legislation applicable to the planning, construction and operation of the Rumah Baru Passenger terminal development is listed in Table 1.1 and will be complied with. This Construction Environmental Management Plan is a guide to onsite compliance with the legislation, as listed in Table 1.1. For more specific information refer to the individual Acts and their Regulations.

Table 1.1 Legislation relevant to the Rumah Baru passenger terminal project

Commonwealth legislation Scope summary

Environmental Protection (Impact of Proposals) Act 1974 (EPIP)1. The Environmental Protection Biodiversity Conservation Act (1999) (EPBC) and associated regulations now replaces the EPIP Act.

The EPIP Act sought to ensure that matters affecting the environment to a significant extent are fully examined and taken into account in Commonwealth government processes. The EPBC Act ensures protection of environmental matters of a national significance. Administered by the Department of Environment, Water, Heritage and the Arts (DEWHA).


Commonwealth legislation Scope summary

Australian Heritage Commission Act (1975) (AHCA)1. The Australian Heritage Council Act (2003) now replaces the AHCA Act.

The AHCA Act sought to provide for the protection of places of significant heritage, both natural and cultural. The Australian Heritage Council Act establishes the Australian Heritage Council who advise the Commonwealth on heritage issues.

Sea Installations Act (1987).

Ensure that sea installations installed in adjacent areas are operated with regard to the safety of the people using them, and the people, vessels and aircraft near them and ensures that installations are operated in a manner that is consistent with the protection of the environment. Administered by the Department of Environment, Water, Heritage and the Arts (DEWHA)

Environment Protection (Sea Dumping) Act 1981 and associated Regulations

The Act regulates the deliberate loading, dumping and incineration of wastes and other matter at sea. The Act and Regulations apply to all vessels, aircraft or platforms in Australian waters and to all Australian vessels in any part of the sea.

Occupational Health and Safety (Commonwealth Employment) Act (1991) (OHSCE)1. The Occupational Health and Safety Act (1991) now replaces the OHSCE Act.

The OHSCE seeks to protect the health, safety and wellbeing of all workers employed by the Commonwealth and Commonwealth agencies as well as other persons at or near the workplace. The Occupational Health and Safety Act seeks to promote the occupational health and safety of persons employed by the Commonwealth, Commonwealth authorities and certain licensed corporations.

Environmental Protection Act (1986) (WA) (CI) (CKI). (EP Act)

The EP Act is the Western Australian environmental protection legislation enacted by the Commonwealth Minister for Territories. With the NOI having been assessed under the EPIP act, the Environmental Protection Act is applied specifically to works activities and licensing during operation.

1 Please note that the Notice of Intend (NOI) for the Rumah Baru Freight and Passenger Terminal was assessed under this Act.


2. Project Description

2.1. Project description and location The proposed Passenger Terminal is located at Rumah Baru on the east side of West Island, part of the Cocos (Keeling) Islands. The marine footprint is shown in Figure 2.1. The construction of the passenger terminal at Rumah Baru has seven main components: • Demobilisation • Bridge construction • Island construction • Dredging works • Onshore works • Installation of beacons and markers • Demobilisation The marine works will comprise the bridge and island construction along with the dredging work. Broadly, the marine works will consist of: • Installation of temporary boat ramp; • Construction of onshore stilling basin; • Dredging temporary access corridor and construction of access bridge from land to the

created island; • Sheet piling for creation of part of the island boundary; • Dredging of access channel, berth and turning basin; • Creation of a protective seawall on part of the island boundary using geotextile tubes and

dredged material; • Land reclamation for the construction of the island; and • Removal of the temporary boat ramp after end construction of the passenger terminal. Each step of the marine component of the passenger terminal construction is outlined in detail in Section 2.


Figure 2.1 Location of the marine footprint of the Passenger Terminal at Rumah Baru on West Island, Cocos (Keeling) Islands.


2.2. Construction methods Clearing and construction of the Rumah Baru freight and passenger facilities will be undertaken in accordance with the relevant clauses of the General Specification (GHD, 2008b).

2.2.1. Temporary boat ramp Prior to cutting off access to the public boat ramp at Rumah Baru, a temporary boat ramp will be constructed. The temporary boat ramp is proposed to be positioned approximately 400 m north of the permanent boat ramp at Rumah Baru, as shown in Figure 2.2. Construction of the temporary boat ramp road access is being carried out by the Shire, and is not dealt with in this document. The dimensions of the temporary boat ramp are approximately 16 m long by 4.5 m wide, as shown in Figure 2.3. It will be constructed using sheets of ‘Flexmat’, which are uniform rectangular pattern of square, trapezoidal concrete blocks cast onto durable polypropylene fabric (Figure 2.3). Flexmat has a fast installation rate (normally exceeding 75m2 per hour) and is readily retrievable and re-deployable in temporary applications. The installation will involve no preparation of the seabed. The boat ramp will be constructed by placing smaller Flexmat sections within the boat ramp footprint in Figure 2.4 using a crane and possibly a support barge. Pins driven through the flexmat at intervals along the edges into the seabed will provide stabilisation. The construction corridor, where some temporary disturbance to the seabed may occur, is estimated to be 3 m on all three marine sides of the boat ramp (i.e. either side and at the seaward end). Once the temporary boat ramp is in place, the construction of the Rumah Baru passenger facilities can start. Once the construction is complete, access to the public boat ramp at Rumah Baru will be reopened, and the temporary boat ramp north of Rumah Baru retrieved. Any habitat underneath the temporary boat ramp will most likely have been adversely impacted, however the small disturbed area is expected to recolonise quickly with Thalassia hemprichii and Caulerpa spp..


Figure 2.2 Rumah Baru passenger facility footprint, location of the current boat ramp, and position of the temporary boat ramp (circled in blue)


Figure 2.3 Layout of the temporary boat ramp north of Rumah Baru.


Figure 2.4 Flexmat installed for recreational boat ramp

2.2.2. Stilling basin construction

Pre-Construction of the basin Prior to constructing the stilling basin, the area set out for clearing will be surveyed and marked. Approvals for clearing will be obtained from the Superintendent on site prior to clearing. After clearing, the area will be resurveyed, the stilling basin defined and a feature survey conducted. A vegetated buffer of at least 10 m will be retained between the beach and the seaward wall of the basin.

Construction of the main basin The stilling basin will be formed by reducing the basin level by 150 mm and pushing the material up to form a perimeter bund. The soil bunds will be shaped as indicated on Figure 2.5 and lightly compacted. The anticipated height of bund will be approximately 1.5 m and several metres wide, however the exact dimensions will be determined on site by the Contractor in consultation with the Superintendent. The bund will be located behind the retained coastal strip of palms and vegetation, which will provide protection from tide and wave action. The base of the main stilling basin will be shaped to fall to the final stilling basins (see below) as indicated on Figure 2.5 to allow excess water from the stilling basin drain.

Construction of the Weir and Final Stilling Basins In order to construct the final stilling basins within the main basin, the exact location of the outlet will be set in liaison with the Superintendent. The expected location is shown in Figure 2.5. A geobag weir with the dimensions 15 m long by 6.4 m wide will be constructed using standard 0.75 m3 geobags. The weir will be situated around the outlet area within the main basin. Initially, two single layers, 5 m apart will be installed, creating two final stilling basins in succession before the outlet. The geobags will be laid in a flat level manner to facilitate evenly distributed overflow of the stilling basin drainage water. As the main basin fills with dredged material, additional layers of geobags will be laid to increase the height of the weir walls. Also a third weir wall will be constructed behind the initial two weir walls, creating three final stilling basins before the outlet. Further geobags will be added to the height of the weir walls, as needed. The final settling basins will be mechanically cleaned as required from solid build-up and the excess material deposited within the main basin in the area designated for material unsuitable for land reclamation purposes (see below).


Construction of the return water outlet The return water outlet to the ocean will cut through the retained 10 m vegetation buffer. The outlet will be a cross-sectional dish design with minimum fall to the ocean. The installation of the outlet will require removal of the beach dune in this area. The outlet is to be lined with Bidem A14 geofabric. If needed, and in consultation with the Superintendent, coral rubble bunds and/or Bidem A14 silt fences may be placed across the dish section to slow return water flows.

Stability of the stilling basin The shape of the bund wall, with its 7 to 10 m wide base and height of 1.6 m provides a suitably stable barrier to the perimeter of the stilling basin. The flow of water to the outfall will be via a series of weirs constructed from sand filled geobags. The bund will be about 40 m from the lagoon shore with a buffer zone of vegetation. The buffer zone will provide protection for the bund wall and stilling basin in the unlikely event of any severe storm action from the lagoon.

Material Placement The finer silt material will be carried in suspension in the runoff from the stilling basin. The flow of runoff will be designed for maximum settlement of suspended particles before flowing over the weirs and into the outlet channel. The fine silt material is expected to settle in the series of stilling basins, as described above under the heading “Construction of the Weir and Final Stilling Basins”. Daily inspections will be carried out to check on the level of build-up of fines, and excavation and relocation of this material will be carried out as required. This material, which will be unsuitable material for landfill and other construction uses, will be relocated using suitable earthmoving equipment (e.g. excavator, bobcat, front end loader or similar) to the most northerly section of the stilling basins separate from the material suitable for land reclamation and other works, which will be stored in the southern section for easy accessibility. These areas may be sign-posted according to the designated use based on quality if necessity dictates. The objective is to minimize the amount of silt material used in road making, geobag and tube filling, and returning to the ocean. Wylie & Skene will carry out sieve analysis of the fill material on a regular basis.


Figure 2.5 Stilling basin


2.2.3. Access bridge and temporary access corridor The access bridge from shore to the reclaimed island (Figure 2.1 and Figure 2.2) will be constructed with precast decking placed on piles to minimise interference with nearshore currents and longshore sand movement at Rumah Baru. The piling will be undertaken by a pile driver mounted on a barge. The first two piles can be driven into the ground from shore at low tide. For pile driving from the third pile out to the beginning of the permanent access channel, the barge will require access either on high tides, or by dredging a temporary access corridor alongside the bridge. The preferred method is to bring the barge inshore and move it on high tides to undertake the necessary works, rather than dredge a temporary access channel (see below), as this will minimise work and potential impacts. However, this option will only be feasible if the barge is able to access the area on high tides, including times when these occur during the night. During these night works, minimal lighting will be used. On the occasions when high tide occurs at night and the barge needs to be moved at night time, no pile driving will be undertaken. The barge will be moved into position and moored so that piling may commence at the required location the following morning. An alternative method is to dredge a temporary access corridor on the north side of the bridge, running from the permanent access channel landwards to the third pile of the bridge. The temporary dredged access corridor will be approximately 14 m wide, and cut through seagrass and macroalgae habitat, as outlined on Figure 2.1. The temporary access corridor will be approximately 1 m deep (CD), and the spoil pumped directly into the stilling pond. No infill of the temporary corridor is proposed after completion of construction of the bridge. When inshore access is possible, either on high tides or after dredging a temporary corridor, the barge with the pile driver will drive the circular piles to the design depth for construction of the bridge. Once the piles are in place, the steel head-stocks will be installed to each pair of circular piles from a barge crane. The barge crane will then lift and place the precast concrete panels from a dumb barge and onto the head stocks. Sufficient depth is needed for the barge when placing the concrete blocks. On the occasions when high tide occurs at night and the barge has been moved inshore and moored, operation of the crane for placement of concrete blocks at night will be necessary. In summary the following activities may take place when high tides occur at night: • Movement of the barge inshore; • Mooring of the barge; and • Operation of the crane for placement of the concrete slabs.

2.2.4. Sheet piling for land reclamation boundary The northern and western edge of the boundary of the land reclamation area will consist of interlocking metal sheet piles, in places enforced with tie rods between two opposing lines of sheet piles to ensure wall stability. The boundary for sheet piling is shown in Figure 2.6. The remaining boundary on the southern and eastern edge will consist of ‘geotextile tubes and bags’ filled with dredged material. The interlocking metal sheet piles will be installed using a crane mounted on a barge. The barge will position and steady itself using multiple anchors, moving along the sheet pile boundary as sheets are installed. The approximate disturbance corridor for sheet piling from the anchors and associated barge movement is 14 m from the sheet piling boundary outwards, as indicated in Figure 2.6. The interlocking metal sheet piles are not watertight and once slurry is placed within the land reclamation area, return water will seep out from the joining sheets. The majority of return water, however, will leave the land reclamation area through main drainage points located every 6 m as indicated on Figure 2.6.


Figure 2.6 Sheet piling along part of the land reclamation.

Shee

t pili

ng

Geo

tete

xtile

tu

bin

g


2.2.5. Dredging and dredge spoil management The proposed access channel, harbour basin and berth pocket is shown in Figure 2.1 and Figure 2.2. The channel will be dredged to obtain sufficient depth for the dredge to access the shallows nearshore. The current and proposed dredge depths are given in Table 2.1. These target depths will yield an approximate volume of dredged material of 38,000 m3, which is anticipated to be sufficient volume for the island reclamation.

Table 2.1 Current and target depths for the dredge programme

Dredge component Current depth (approx)

(m) Target depth (m)

Approach channel 1.5-3 2.85

Harbour basin 0.6-1.7 3.15

Berth pocket 1-1.3 3.65

Dredging will be undertaken using a ‘Gen 1 Amphibian Dredger’ similar to the model shown in Figure 2.7. The dredge is a crawler type with the spoil travelling via a floating pipeline directly into the stilling basin at Rumah Baru. The spoil will be pumped to the back of the stilling basin (furthest away from the beach) letting the return water pond at the front of the basins, allowing the maximum amounts of solids to settle out prior to discharge over a set of weirs and through a lined channel to the ocean. The stilling basin will have one return water outlet, positioned as shown in Figure 2.5. The last section of the dredging to be completed will be the area in front of the piled births. We propose to have the fill placed at the back of the piling prior to the dredge demobilising so this section of work can be dredged using the dredger. In certain instances spoil may be pumped directly from the dredger into the geotextile bags and/or offshore island, as described below. No overflow will occur at the dredge site as all spoil will be pumped directly into the stilling basin. ‘Overflow’ will occur here through the return water outlet, as described in more detail in Section 2.2.2. ‘Overflow’ will also occur with the return water from the land reclamation boundary, as detailed in Section 2.2.6. Designated outlets are present at both the stilling basin (one outlet) and at the land reclamation boundary (several).


Figure 2.7 Amphibian Dredger

2.2.6. Land reclamation – offshore island Geotextile tubes and bags will be filled with slurry and positioned along the southern and eastern edge of the land reclamation area as shown in Figure 2.6, and cross-section in Figure 2.8. The geotextile tubes and bags are made from high strength, woven, polypropylene geotextile, as shown in Figure 2.9. The standard 1200R material has a pore size of less than 75 μm and a flow rate of 27L/m2/s, For the Rumah Baru project this geotextile will be covered with “vandal deterrent" material comprised of coarse, strong, interwoven fibres. These layers will be added to both sides of the geotextile fabric to avoid coral pieces cutting through the tubes from the inside, and to minimise wear and tear from the outsides of the tubes, which will be exposed to the environment. The sizes of geotextile tubes to be used are 20 m x 4.8 m x 2.1 m. There will be two sizes of Geotextile bags installed in the works, 1.6 m x 1.2 m x 0.4 m and 2.4 m x 1.8 m x 0.65 m respectively. The large geotextile tubes are proposed to be filled in situ on the seabed by directing the pipe with slurry from the stilling basin (or possibly straight from the dredge) to the opening in the tubes while they are positioned on the seabed. The pipe will be directed by a person on snorkel, as the depth of water is less than 2 m. Slurry will be pumped into the tube, with water seeping out through the geotextile tube material during filling. When the tube is full, slurry will spill over the top, however care will be taken to minimise this to reduce turbidity. Once each tube is full, it will be closed with a flap and stitched up. The tubes will not be anchored to the seabed, but will be held in place by gravity and ultimately anchored into the land reclamation area. An example of full geotextile tubes is shown in Figure 2.9. Once sufficient geotextile tubes have been filled and positioned to create the boundary seawall, slurry will be pumped directly into the land reclamation area. For the initial filling along the land reclamation boundary, the coarsest dredge spoil will be sourced from the stilling pond, mobilised into a slurry using seawater, and pumped via a floating pipeline to the land reclamation area. Using the coarsest material along the perimeter will ensure that the creation of turbidity by release of fines through the sheet piling and the geotextile tube wall will be minimised. Once the coarse material is in place, the finer material will be pumped into


the middle of the reclamation area. If the timing is favourable, slurry may at this stage be pumped directly from the dredge into the land reclamation area. When land has been created, the material will be levelled for the creation of a working area for filling the remaining geotextile bags. The bags may be filled on the newly reclaimed land, and positioned on the seawall as shown in Figure 2.8 for finalisation of the land reclamation boundary. Alternatively, the remaining bags may be filled by pumping slurry from the stilling pond to a barge sitting near the area of the seawall. Filled bags will in this case be placed on the seawall from the barge using a crane to complete the boundary. Both these methods are likely to be used, with filling taking place on the barge until sufficient land is created for filling to take place. The decision of when to use each method will lie with the contractor. In either scenario, water will seep through the sides of the bags, creating localised turbidity in the receiving water. As the geotextile material is produced to retain solids, only the very finest fragments will seep through. Overflow from the stilling basin and spillage of slurry from the opening of the geotextile tubes when filled in situ is anticipated to be the primary source of turbidity during the construction phase.


Figure 2.8 Position of geotextile tubes for the creation of the seawall.


Figure 2.9 Geotextile material (left) and filled geotextile tubes (right)

2.3. Construction schedule The on-site construction activity schedule is given in Table 2.2 however the exact timing is subject to change as the project progresses. Based on Table 2.2 the approximate timing of the marine components is summarised in Table 2.3. Delay, rather than progress ahead of schedule, is considered most likely, and dredging will not take place before June 2009.


Table 2.2 Draft schedule for the onsite construction (as of March 10, 2009), subject to approval by the Superintendant


Table 2.3 Draft schedule for main components of dredging and other turbidity generating works, 2009

Activity April May June July Aug Sep Oct Nov

Installation of temporary boat ramp x

Pile driving for access bridge x x x x

Sheet piling etc x x x x x x

Prepare stilling basin x x

Install silt curtains x

Dredging to level land reclamation footprint

x

Dredging of channel, turning basin and berth

x x x x x

Fill geobags in situ x

Fill and place geobags, land fill x x x x x x


3. Management commitments

3.1. General induction

3.1.1. Management Objective That all personnel involved in the project are aware of the potential environmental impacts of the proposed works and management strategies that have been developed to minimise or eliminate these impacts.

3.1.2. Performance indicators: • Wylie & Skene is responsible for developing and implementing the induction process,

based on the requirements of the CEMP (this document). • Attendance records for induction training is monitored to make certain all workers have

undergone satisfactory induction.

3.1.3. Induction requirements Wylie & Skene shall ensure that all personnel involved in construction works undergo a suitable induction program to make sure that they are aware of potential environmental issues associated with the project. The induction shall be carried out prior to any works commencing and any newly arrived or local personnel shall be inducted before being allowed to undertake any construction works. The induction program as a minimum will include information on the following issues: • The need to conserve the marine environment of the Cocos (Keeling) Islands; • The risks of a spill to the marine environment, spill clean up techniques and procedures,

and emergency procedures to follow in the event of a spill; • Protection of public and private property; • Risks related to piling and dredging in the marine environment; • Noise and dust; • Pressure waves and vibration; • Awareness of water quality; and • Occupational health and safety. Wylie & Skene shall make sure that employees are sensitive to their cultural surroundings and establish codes of behaviour to make certain there is minimal disruption to the local communities. Induction training for construction staff will include awareness of procedures to be followed in the event that any material of cultural significance is uncovered. Before the induction program is put in place, it will first be approved by the Superintendent. Wylie & Skene shall note that inspection of work practices and/or results by DEWHA may occur. This would normally occur in the presence of the Superintendent and any outcomes of the inspection resulting in changes to works practices will be communicated to Wylie & Skene by the Superintendent.

3.1.4. Corrective Actions Where it is found by Wylie & Skene that an employee has not undergone satisfactory induction in relation to environmental, cultural, and health and safety education, the employee must immediately cease work until a suitable induction has been undertaken.

3.2. Marine Flora and Fauna

3.2.1. Management Objective That activities undertaken during construction and operation of the freight and passenger facilities at Rumah Baru do not cause unacceptable effects on marine flora and fauna in the Cocos (Keeling) Islands Lagoon area.


3.2.2. Performance Indicators • No detrimental impacts on the marine flora and fauna outside the 50 m buffer zone.

3.2.3. Potential impacts The impact assessment concluded that no significant, long-term impacts are expected from the construction on marine flora and fauna in the lagoon. The following potential issues were identified in the NOI or EMP or raised by DEWHA: • Direct loss of seagrass, macroalgae and coral bommies within dredging and land

reclamation footprint; • Direct disturbance of seagrass, macroalgae and coral bommies within the construction

buffer zone (50 m); • Potential indirect impacts on seagrass, macroalgae and coral from the dredge and return

water plumes (light deprivation and excessive sedimentation); • Potential impact on coral spawning from increased loads of suspended solids and

sedimentation; • Disturbance to turtles from interactions with vessels and dredger; and • Disturbance to turtles from light spillage, noise and vibration from construction. Most of the species identified during the baseline and interim surveys can be regarded as common and will not be considerably impacted by the development at Rumah Baru. The exception are the green turtle, (Chelonia mydas), and hawksbill turtle (Eretmochelys imbricata), which are both listed species under the EPBC Act 1999. The proposed management approaches to avoid environmental impacts are outlined in Table 3.1. Some management commitments outlined in the EMP (GHD, 2008a) are proposed revised, as discussed in Section 3.2.4 and 3.2.5.

3.2.4. Turtle Exclusion Device The EMP specified that a “Turtle Excluding Device (TED) will be fitted to the dredge in accordance with current best practice”. A TED is typically used on a Trailer Suction Hopper Dredge (TSHD) to warn sleeping turtles of the approach of the drag head. This system was developed for use in the United States, where turtles hibernate in the sediments when water temperatures are below 18˚C. They become sluggish and do not react to external stimuli (Morton, 2007 -Appendix A). Two different TEDs are shown in Figure 3.1. As shown in Figure 2.7 the type of dredge to be used at Rumah Baru is not a conventional TSHD, but rather a type of Cutter Suction Dredge (CSD) with a cutterhead protruding in front of the drag head. TEDs are generally not fitted onto CSDs, where the action of the cutterhead acts to warn turtles prior to contact. Further, turtles do not hibernate in the waters off Cocos (Keeling) Island, and the year round warm waters means that they will be ‘alert’ to and ‘wary’ of anthropogenic noise and react to movement with avoidance behaviour (GHD, 2008a). The noise and vibration from the cutterhead is therefore highly likely to alert any turtles prior to contact with the ‘draghead’, especially as the turtles will not be hibernating or asleep in the nearshore environment off Rumah Baru, where the development is proposed. A cutterhead in this instance considered much superior in warning unaware turtles prior to contact, than a TED would be. It is therefore considered that a TED will not increase the protection of turtles. In addition, turtles tend to use the area off Rumah Baru mainly at night, when they come nearshore to feed (Maunsell, 2003). During the day they are generally found resting in the middle of the lagoon (Maunsell, 2003). Dredging will only take place during daylight hours, and interaction between turtles and the dredge is therefore extremely unlikely. In summary, the use of TEDs is not considered a useful management measure in this particular case, for the following reasons:


• The dredge type is not suitable to fit TEDs; • The noise and vibration from the cutterheads will act to alert and scare away turtles prior

to any contact; • The year round water temperatures are such that turtles will not be sluggish or

hibernating; • Turtles do not hibernate in the area and have been observed to react to human stimulus

with a escape reaction, and are highly likely to respond to noise and vibration from the cutter heads; and

• Turtles are mostly present feeding in the area at night when no dredging will take place. The risk of injuring and killing turtles from interaction with the dredge cutterhead is proposed managed as detailed in Table 3.1 under the heading “Turtle death/injury from interaction with dredge”.

Figure 3.1 Turtle exclusion devices fitted to TSD drag heads: chains (left) and plough (right) (Morton, 2007-Appendix A)

3.2.5. Silt Curtains The EMP stipulated that “a silt curtain shall be placed around the works area prior to dredging to contain sediments produced from the dredging activity”. While the use of silt curtains is appropriate for the Rumah Baru project, it is not perceived as the most effective approach to place silt curtains around ‘the works area’ in its entirety at all times. The effectiveness of a silt curtain depends to a large degree on site specific conditions such as the location of sensitive habitats in relation to the creation of turbidity. A silt curtain can deflect a plume, letting fines settle and form a turbid layer along the bottom. However this layer may flow onto nearby corals and seagrass/macroalgae in the gap between the bottom of the silt curtain and the seabed. Depending on the specific conditions, it may be preferable to let the fines stay in suspension and form a larger plume which will not settle out in a restricted area, thereby avoiding mass sedimentation onto sensitive habitats and letting the plume cause light attenuation over a wider area during dispersal (USACE, 2005 - Appendix B). Potential issues with placing silt curtains around the work area are outlined below: • The maintenance of silt curtains across a large area would be difficult with the currents

and wave climate at Rumah Baru; • The difficulties could slow down the dredging programme. This would have implications

for time and cost, and is not environmentally desirable as an effective dredging management approach is to minimise the duration of the impact;

• Silt curtains require extensive anchoring in currents, and pose navigation hazards; • When deployed in currents, silt curtains can mechanically damage benthic communities as

water movements exerts pressure on the curtains from varying directions; • In addition, the release of fines into the water column happens only to a minor degree at

the cutter/drag head. Turbidity is predominantly created from overflow from the hopper of a dredge, and at return water outlets. Turbidity during the Rumah Baru project is likely to be created primarily at the return water outlet, and at the site of geotextile tube filling.


To enhance the effectiveness of the use of silt curtains, it is proposed to use them selectively spatially and temporally with the focus on reducing the spread suspended sediments from return water discharges, and to deflect plumes from sensitive areas, as detailed in Section 6.3. It is considered to be feasible and effective to deploy silt curtains as shown in Figure 2.5 and listed below: • Around stilling pond return water outlet (one or two, as required); • If conditions are too rough the silt curtain can be placed on the inside of the stilling pond; • At or around the filling site where geotextile tubes are filled, subject to the creation of

turbidity and the monitoring programme findings; and • At or around the return water outlets from the land reclamation area (south and eastern

side), subject to the creation of turbidity and the reactive monitoring programme findings (one or two, as required).

• If the conditions are favourable it may be possible to deploy a silt curtain south of the bommie field immediately north of the proposed channel. Depending on site conditions this may aid in deflecting the plume around either side of the bommie field, as the plume is expected to flow predominantly north out of the lagoon.

It is proposed that sufficient silt curtains be kept on site for deployment ad hoc during the dredge programme whenever turbidity is created and it is feasible to deploy and appropriately anchor a silt curtain for the mitigation of turbidity. As discussed further in Section 5 it is proposed to monitor the extent of the plume from an elevated platform such as a ‘cherry picker’ or scaffold platform. The source of turbidity, the need for silt curtains, and the effectiveness of deployed silt curtains is proposed to be assessed from this elevated position on a daily basis. When a silt curtain is deployed, it will be inspected by the Wylie & Skene supervisor on a daily basis to ensure structural integrity. If the silt curtain is found to be damaged during regular inspection and exceedence of the trigger level value and duration is occurring, work will immediately cease until the silt curtain is repaired by the Contractor and functioning properly. To avoid accidental damage by the silt curtain to benthic habitats in the wider lagoon, dredging will cease immediately and the silt curtains removed (if possible) upon the warning of extreme weather events (as forecast the Bureau of Meteorology). Dredging and deployment of silt curtains will not happen until the event has either passed or the Bureau of Meteorology has retracted the warning. The specifications of the silts curtains to be used during the project are attached in Appendix C.

3.2.6. Noise and vibration impacts to turtles The primary sources of noise and vibration in the marine environment will be generated by the pile driving associated with the construction of the access bridge and sheet piling for the land reclamation boundary. These activities are described in Section 2.2.3 and Section 2.2.4. The duration of pile driving is currently estimated at 30 days, and the sheet piling at 43 days. The location of the access bridge is perpendicular to the beach out to 200 m offshore. The land reclamation boundary is located between 200-300 m from shore. The source of the noise and vibration will thus be within 300 m of Rumah Baru. While the hearing range of turtles overlap with the noise frequency emitted by pile driving, the noise and vibration generated at the pile driving site will attenuate rapidly with distance. During the day the turtles are generally not present nearshore at Rumah Baru, however, they may still be within hearing range across the lagoon. The management measures for pile driving are based on the assumption that turtles will avoid excess noise and vibration, if they are appropriately warned prior to piling commence. This will prevent hearing injuries and other lasting impact. However, as turtles are present within the lagoon during the day


(anecdotal information and observations during the baseline survey 2009 indicate that they spend the day resting in the middle of the lagoon) transient impacts on behaviour may occur. The only works to be undertaken at night are moving the barge in the near-shore area on high tides (Section 2.2.3). No pile driving will be undertaken at night. However, placement of the concrete slabs may take place during the night on the high tides, and this will include operation of the crane on the barge. This may produce some low-level underwater noise associated with the barge movement and the crane operation. The risk of injury or death to turtles is negligible, as the barge moves slowly and will allow any turtles to display avoidance behaviour. Some transient behaviour impacts may occur, with turtles avoiding the area immediately around the barge for feeding due to the anthropogenic presence. The management measures for pile driving and sheet piling are summarised in Table 3.1 and listed below: • Pile driving and sheet piling will only take place during daylight hours. • An exclusion zone of 500 m around the site of the pile driving will be observed for ten

minutes prior to any pile driving activities. If any turtles are present, work will not commence until the zone is clear.

• Once the exclusion zone is clear, mechanical soft start will be undertaken prior to commencement of the piling activity. This will be undertaken by piling at low energy levels (‘fairy taps’) and then building up to full impact force. This will alert any turtles present within the range of the noise and vibration, and offer an opportunity for avoidance behaviour.

• Piling will cease if a turtle(s) is sighted and only recommence when the turtle(s) had either been observed to move out of the zone or has not been resighted for 10 minutes.

Oceanica: Wyllie & Skene: Rumah Baru Freight and Passenger Facilities, Construction Environmental management Plan 27

Table 3.1 Management approaches for the protection of marine flora and fauna during construction

Potential impact Expected impact Comment Management measures

Responsible party

1

Removal of seagrass and macroalgae within dredge and island footprint, causing impact on an ecosystem level

No significant impact expected

Area of removal is small (estimated 1% of the benthic flora on the north-eastern coast of West Island) (GHD, 2008a); Small loss on community scale considered to be insignificant (GHD, 2008a); Historical channel construction and maintenance activities have not resulted in any deterioration of the marine benthos beyond the area of direct impact; in fact, Caulerpa spp. And Thalassia hemprichii have recolonised this area (GHD, 2008a; confirmed by observations made during the baseline survey 2009); No evidence of erosion was observed at the sides of the existing channel and they are covered with seagrass and macroalgae (GHD, 2008a; confirmed by observations made during the baseline survey 2009); High ability of benthic flora to regenerate after anthropogenic impact (Op. cit.) and natural events (observations made during the baseline survey 2009)

Restriction of mechanical impact from slew anchors and construction barges/vessels and equipment to within the set disturbance corridor of 15 m around any structure; No significant long-term impact on seagrass and macroalgae outside the buffer zone of 50 m around the project footprint, as ensured through the CEMP.

Wylie & Skene

2 Impact to distribution of Thalassia hemprichii due to change in sediment regime caused by the construction and dredging

No significant impact expected Thalassia hemprichii adapted to anchoring in differing substrate types (GHD, 2008a)

None proposed Wylie & Skene

3

Seagrass/macro-algae impacts from light deprivation from persistent high plume turbidity

Significant impact not expected, some temporary impacts may occur

Dredging and land reclamation is of medium duration (6 months); Thalassia hemprichii and Caulerpa spp. Naturally tolerant of a range of light intensities (GHD, 2008a); Some temporary impacts may occur, but Thalassia hemprichii and Caulerpa spp. Have rapid growth rates and a high capacity for recolonisation; Previous monitoring has shown that the seagrass and macroalgae beds are highly variable in species composition and have shown shifts from 0-100% presence between surveys indicating a high potential for recolonisation (Maunsell, 2003).

As per the Water Quality monitoring programme Wylie & Skene

4

Coral impacts from light deprivation from persistent high plume turbidity

Impacts not expected but may occur

Construction is of medium duration (6 months); Porites is tolerant to light deprivation (Gilmour et al., 2005); However it is not known at which levels/durations light deprivation and increased sedimentation will synergistically cause impacts to the corals, and plume production must be managed


5

Coral impacts from sedimentation from dredging and land reclamation Impacts may occur

Species relatively tolerant to sedimentation (Gilmour et al., 2005); Coral colonies in form of bommies where even sedimentation on all surfaces is highly unlikely; Coral bommies appear to cope with sedimentation by shedding mucous sheets (Jo Buckee, pers com January 2009, observations made during the baseline survey 2009); However it is not known at which point additional sedimentation to the natural background level will produce impacts and plume production must be managed.


6 Permanent destruction removal of corals inside dredge area

Impacts expected Unavoidable impact to coral bommies located within the proposed dredge channel

Coral survey pre-construction (during baseline survey) to verify the five nominated bommies for removal Relocation as per the bommie relocation plan (Section 7)

Wylie & Skene

7 Coral spawning: adverse impact on fertilisation of gametes due to suspended solids

No impacts expected

Lagoon wide coral spawning may take place as early as February, though it may also occur in March/April; The Porites bommies are likely to spawn in November/December and not partake in the lagoon wide mass coral spawning.

As per the coral spawning management plan (Section 6.5); and All turbidity creating activities will stop if/when coral spawning is observed until one day after coral spawning has terminated.

Wylie & Skene

8

Impacts to benthic habitats and marine life from silt curtains

No impacts expected Silt curtains will be deployed and anchored according to site conditions.

The Bureau of Meteorology (BoM) weather forecast and warnings will be monitored daily for any forecast of extreme weather events (e.g. cyclones); Dredging will cease immediately upon the warning of an extreme weather event and will not recommence until the event has either passed or the BoM has retracted the warning; Silt curtains will be removed prior to extreme event occurring (if possible).

Wylie & Skene

9

Impacts on turtles from light spillage during occasional periods of night-time construction.

No significant impacts expected; Transient impact on behaviour may occur

Turtles are present off Rumah Baru predominantly at night and early morning (feeding) (GHD, 2008a, confirmed by observations made during the baseline survey 2009); During barge movements on high tides (as described in Section 2.2.3) during the night, light spillage from the barge may disturb feeding turtles, however impacts will be transient.

The only night-time activities will be barge movement and slab placement. to take advantage of high tides (as described in Section 2.2.3); Lights on the barge for movement at night, and while placing concrete slabs, will be kept to a minimum (see below); and Lights to meet navigation safety requirements will be fitted to all vessels and marine structure.

Wylie & Skene

28 Oceanica: Wyllie & Skene / VDM: Rumah Baru Freight and Passenger Facilities, Construction Environmental management Plan

Potential impact Expected impact Comment Management measures

Responsible party

10

Disturbance impacts on turtles from noise and vibration (pile driving and sheet piling)

No significant impacts expected; Transient impact on behaviour may occur

Turtles are present off Rumah Baru predominantly at night and early morning (feeding) (Op.cit); Pile driving and sheet piling will only be undertaken during daylight hours; and Turtles off Rumah Baru have been found to be alert and aware and responding readily to anthropogenic presence by swimming away (GHD, 2008a, confirmed by observations made during the baseline survey 2009).

Pile driving and sheet piling will only take place during daylight hours; An exclusion zone of 500 m around the site of the pile driving will be observed for 10 minutes prior to any pile driving activities. If any turtles are present, work will not commence until the zone is clear; and Once the exclusion zone is clear, mechanical soft start (‘fairy taps’) will be undertaken prior to commencement of the piling activity. Piling will cease if a turtle(s) is sighted and only recommence when the turtle(s) has either been observed to move out of the zone or has not been resighted for 10 minutes.

Wylie & Skene

11

Turtle injury/death from boat strikes No impacts expected but may occur

Turtles are present off Rumah Baru predominantly at night and early morning (feeding) (Op. cit.); Vessels will be operating predominantly during day light hours (the only exception is barge movements associated with pile driving, as described in Section 2.2.3); and Turtles off Rumah Baru have been found to be alert and aware and responding readily to anthropogenic presence by swimming away (Op. cit.)

Ferry operation to take place only during daylight hours; Dredging will only occur during daylight hours; Barge movements at night will be undertaken at slow speeds; Limit and enforce a speed limit of 8 knots for vessels within the nearshore of the channel and basin; Vessel and barge operators to keep a vigilant lookout for turtles at all times; and Injuries/deaths of any turtles as a result of construction should be reported immediately by the Contractor to the Superintendent and to DEWHA.

Wylie & Skene

12

Turtle death/injury from interaction with dredge

No significant impact expected

Turtles are present off Rumah Baru predominantly at night and early morning (feeding) (Op. cit.); Turtles off Rumah Baru have been found to be alert and aware and responding readily to anthropogenic presence by swimming away (Op. cit.); The dredge will be operating during day light hours only; and The cutterhead noise and vibration is highly likely to alert turtles prior to physical interaction with the dredger.

The dredge uses a rotating cutter head, which will produce noise and water movement at the seabed, warning turtles prior to approach; Dredging moves very slowly and will only occur during daylight hours; Prior to operating the dredge a 10 min look-out will be undertaken. If turtles are present within 100 m of the dredge, dredging will not commence until the turtles have moved out of the 100 m radius around the dredge; The dredge will only be turned on once the cutterhead is in position for dredging and will be turned off once it is no longer required. The dredge (and cutterhead) will not be in operation when it is being placed into and pulled out of the water; Injuries/deaths of any turtles as a result of construction will be reported by the Contractor in the Complaints Register, to the Superintendent and to DEWHA; If a turtle is injured/killed from interaction with the cutterhead a dedicated turtle watch will commence on the dredge, with dredging to pause if a turtle is observed within 50 m of the dredge; In the event that two turtles are killed then dredging works will cease until a revised management approach can be developed and approved by DEWHA; and Any sighting of turtles near the dredge cutterhead during daylight hours will be reported.

Wylie & Skene


3.3. Terrestrial Flora and Fauna Wylie & Skene are to ensure that construction activities do not cause detrimental effects on terrestrial flora and fauna native to Cocos (Keeling) Islands. Wylie & Skene will be required to clear an approved area prior to commencing construction works. Clearance permits will be obtained (where required) and the area survey checked to ensure it is the correct locations. The Client will approve the clearance area prior to work being carried out. Wylie & Skene will be required to clear 550 m of existing road (from the turnoff at Sydney Highway to the new realigned road transition). This will be done to accommodate the installation of a drain and working area for plant during construction. The side of this section of the alignment will be rehabilitated with local topsoil. The following actions are required to ensure that flora and fauna impacts can be effectively managed: • Any unnecessary removal or damage to native vegetation during construction will be

avoided; • Areas to be disturbed are to be clearly flagged prior to the commencement of work; • All strands of Calophyllum inophyllum and other significant flora will be protected; • Coconut palms and other vegetation within the 20 m wide foreshore protection zone will

be retained where practical to provide a wind break for onshore freight and passenger operations, including car park facilities;

• Trees to be removed will be felled in a manner that ensures they fall within the approved clearing area or onto already cleared land;

• If removal of any major strand trees become necessary, then consultation with the superintendent and DEWHA will be undertaken prior to any action being taken;

• The unnecessary removal of vegetation will be reported to the Superintendent and noted in the Complaints Register by Wylie & Skene, and

• All strands of Calophyllum inophyllum and other significant flora will be identified prior to the clearing activities commencing and markings on the remaining trees will be maintained by Wylie & Skene; and

• Wylie & Skene will acquire necessary permits from DEWHA with regards to any protected fauna on the island.

• The results of the protected fauna survey, detailed in Section 8.7 of the EMP (GHD, 2008a) showed that there would be no significant impacts on the Fiddler Crab habitat in respect of the stilling basin.

Wylie & Skene will meet the following requirements as a pre-requisite for utilising the existing cleared areas at the water galleries along Rumah Baru Access Road as a dry storage facility during construction: • Wylie & Skene shall be responsible for protecting the existing assets i.e. fencing for

bollards etc; and • Wylie & Skene shall be responsible for full reinstatement of the gallery areas after

completion.” Refer to the requirements outlined in Section 8.7 of the EMP (GHD, 2008a).

3.4. Terrestrial Water Quality Management Wylie & Skene will ensure that the northern freshwater lens (if used during construction) is maintained and continues to be of potable quality throughout the construction phase. The following actions are required to ensure that potential water quality management impacts can be effectively managed: • A selection of existing monitoring bores within the freshwater lens and one outside of the

lens will be monitored on a weekly basis by Wylie & Skene to make sure that no contamination of the water supply occurs. These bores will also be monitored prior to the commencement of construction activities to assess the background water quality levels; and

30 Oceanica: Wyllie & Skene: Rumah Baru Freight and Passenger Facilities, Construction Environmental management Plan

• Quarterly reports of water quality monitoring will be sent by Wylie & Skene to the Superintendent and will be made available to DEWHA.

Refer to the requirements outlined in Section 8.3 of the EMP (GHD, 2008a).

3.5. Traffic and Disturbance to the Population Traffic movements on the island will be minimal however a necessary means of transport for deliveries and general movement around site. Traffic movements will be managed to not cause significant disturbances to the Cocos (Keeling) Island population. Recreational facilities and activities should not be impacted by construction traffic movement as the boat ramp will be temporarily relocated and recreational activities such as fishing and swimming will be temporarily suspended during the construction phase. The following actions are required to ensure that traffic management impacts can be effectively managed: • Signage to be erected around the construction area to advise of recreational activity

restrictions and “construction exclusion zone”; • Minimise community disruption during construction phase; • Speed limits signposted in the construction area; • Driver responsibility to be outlined in Wylie & Skene induction package outlining

construction zone and traffic restrictions outside of this area; • Access to water galleries, Sub Station 5 and the wet tip via Rumah Baru Road will be

maintained throughout construction, unless agreed with the relevant authorities; and • The community will be made aware of the construction activities being undertaken via

local media, particularly noticeboards and VKW local radio daily notices. Refer to the requirements outlined in Section 8.5 of the EMP (GHD, 2008a).

3.6. Noise and vibration Noise and vibration are important considerations on this project and there will be some short term noise impacts associated with the use of heavy construction equipment and pile driving. Localised noise is not expected to impact on residents as the nearest residence is 2km away. The following actions are required to ensure that noise and vibration impacts can be effectively managed: • All noise generating construction equipment will be appropriately muffled, housed or

acoustically baffled in compliance with installation standards and building codes to ensure compliance with the Environmental Protection (Noise) Regulations 1997;

• All construction work will be carried out using construction equipment in good working order;

• Work will only be carried out during daylight hours (the only exception is barge movements (associated with but not including pile driving) and placement of concrete slabs for the access bridge, as described in Section 2.2.3 with management measures given in Section 3.2.6);

• In the event work is to be conducted outside daylight hours, a noise management plan will be prepared by Wylie & Skene for the activity undertaken and residents will be notified via letters or other correspondence;

• Wylie & Skene shall conduct noise monitoring and record the results. • Construction equipment will be inspected weekly by Wylie & Skene to ensure good

working order of any noise minimization fittings. Wylie & Skene aims to manage noise and vibration to ensure no adverse impact to residents or the environment and hence to prevent complaints. Construction noise shall be restricted to the levels set out in AS 2436-1981 (Guide to Noise Control on Construction, Maintenance and Demolition Sites) and in accordance with the Environmental Protection (Noise) Regulation 1997.


The nature of the construction work on this project does not require a significant concentration of noise generating plant and equipment at any one time in the same vicinity and therefore excessive noise is not expected. Should a need arise to measure noise levels, the Site Project Manager will engage a NATA certified technician to take appropriate readings. Should noise levels prove to be excessive, the Site Project Manager will initiate appropriate control measures. Refer to the requirements outlined in Section 8.4 of the EMP (GHD, 2008a). For marine noise and vibration see Section 3.2.6.

3.7. Rehabilitation and Visual Environment Wylie & Skene will maintain visual amenity of the site of the Rumah Baru works as is practicable and shall ensure it does not deteriorate due to activities associated with the construction and operations of the passenger and freight handling facilities. The primary objective is to minimize the amount of excess dredged material. If there is surplus material left on completion of the works, it will be stockpiled for potential use by the Shire, who have expressed strong interest in accessing the material for their use. The Shire has advised that the material would need to be used within six months of stockpiling to avoid it being rendered unusable by vegetation establishing on the material. The total volume excess dredge material is expected to be no more than 10 000 m3 and will be placed in consultation with the Shire. The portion of this excess dredge material deemed usable by the Shire will be stockpiled as instructed by the Shire with height and girth of the pile to be determined by the amount of surplus material. Any of the material not required by the shire (i.e. <10 000 m3) will be levelled over the area of the stilling basin and mulched to avoid erosion, then left for revegetation to occur naturally (generally colonisation is under way after six months). The following actions are required to ensure that the visual amenity is not impacted and can be effectively managed: • The removal of vegetation shall be minimized to make certain that visual amenity impacts

are minimized; • The project area boundaries shall be delineated to make sure that the surrounding areas

(not forming part of the project area) are adequately protected and not used for car parking, heavy machinery turnarounds, storage areas and dumping sites;

• Excess dredge material in the stilling basin will be pushed into a stockpile for future use; • Coconut palms and other vegetation within the 20 m wide foreshore buffer zone will be

retained where practicable to provide a wind break for onshore freight and passenger operations, including car park facilities; and

• On completion of earthworks the batter slopes and redundant road pavement areas are to be stabilized with local mulch. The provision of these mulched surfaces is for general appearances, to prevent scour and generally stabilize the area from windblown sand.


3.8. Quarantine Quarantine restrictions apply on site to protect the environmental sensitivity of the island and to make sure that non-native species are not introduced to the islands. Wylie & Skene will ensure that quarantine rules as they pertain to Cocos (Keeling) Island and will ensure that compliance to import export restrictions are adhered to. All equipment and materials will be inspected and passed through quarantine prior to being sent to the island. Wylie & Skene will monitor this material and keep records. The following actions are required to ensure that the quarantine restrictions are not impacted and can be effectively managed: • All imported materials will be stored in a designated area and inspected by AQIS prior to

use;


• All Wylie & Skene personnel and subcontractors will be informed of quarantine requirements prior to being mobilized to the island;

• Each person entering site shall be made aware of the quarantine requirements whilst working on the island; and

• Consult with and obtain certification from AQIS and the Department of Fisheries regarding Invasive Marine Pest Species (IMPs) for vessels accessing the Cocos (Keeling) Islands.


3.9. Archaeology and Heritage Wylie & Skene shall ensure that existing or potential locations of relics of cultural or historical significance are identified and protected during the construction works associated with the freight and passenger facilities. The following actions are required to ensure that the heritage sites are not impacted and can be effectively managed: • If any items suspected to be of an archaeological or historic nature are uncovered during

construction work will stop immediately in the vicinity to avoid accidental disturbance; • Wylie & Skene will immediately inform the Superintendent of any heritage items that are

uncovered during the construction works; • Appropriate conservation of any items found with significant heritage value will be

ensured; and • Wylie & Skene will provide induction training for the site construction staff to include

awareness of procedures to be followed in the event that any material of cultural significance is uncovered.


3.10. Construction Waste Management Wylie & Skene will ensure that all construction activities are carried out within the principles of cleaner production and waste minimization. All construction work results in the production of some waste products. Waste such as litter and general construction waste are expected to be produced, however disposal of these products will be undertaken to minimize the impact upon the environment. The following actions are required to ensure that the construction waste does not impact the environment and can be effectively managed: • All construction waste is to be removed from the construction area; • Construction waste will be segregated where possible and recycled; • Wylie & Skene’s induction of its workforce will outline the requirements for waste

minimization and management practices. All workers will be encouraged to minimize waste production and to make sure that any wastes produced are disposed of appropriately;

• All staff working on the project must not dispose of litter (including wrappings, plastic takeaway containers, drink cans, cigarette butts and construction waste) into the water, or leave it where it may end up in the water. All litter produced on site shall be disposed of in accordance with the SCKI waste disposal requirements;

• Any waste produced (including construction) that is disposed of to the licensed landfills shall be done in accordance with the SCKI requirements. Waste that is disposed of to locations other than licensed landfills shall be done so in accordance with landowner and DEHWA instructions; and

• All materials imported to the island will be required to have minimal packaging and where possible constructed before shipment.



3.11. Pollution Control during Construction and Operation During construction there is a low risk of pollution as a result of accidental spillage of fuels. However, any spill during construction has the potential to cause detrimental effects on the environment. The following actions are required to ensure that pollution does not impact the environment during construction: • During construction a suitable spill Response Kit will be provided by Wylie & Skene. • The spill kit shall contain as a minimum - containment booms, shovel to apply and clean

up absorbent material, drum to store absorbent material, fire extinguisher, spill pillows, proprietary material used to absorb material, appropriate PPE for persons involved with cleaning up the spill;

• As part of the spill response an empty tank with vacuum pump and hose for collection of spilt liquid will be located nearby;

• The Spill Response Kit will need to be inspected by Wylie & Skene during construction on a monthly basis to make certain that all items are in working order and accounted for;

• Specific personnel will be trained to use the spill response kit; these personnel will have mobile communication readily available to them;

• No major servicing (including oil changes) of plant and equipment shall be undertaken on the offshore island unless there is no practical alternative. If major servicing on the Offshore Island is necessary, the Superintendent must be informed and the servicing shall be carried out in a safe, sealed area;

• During construction, all temporary tanks will be bunded and located away from the freshwater lens;

• Any plant and equipment found to be leaking (i.e. fuels, fluids and oils) must be immediately taken out of action and removed to a safe sealed area for repair; and

• When refueling occurs there will be an ample amount of rags on hand to clean up minor spills.

In the event of a major spill, Wylie & Skene will: • Make sure the safety of the area of the spill and evacuate non-essential personnel; • Deploy the spill response kit and trained personnel immediately to reduce the area of

impact; • Use best endeavours to stop the source of the pollution; • Inform all emergency services via telephone of the situation; and • If an accident occurs at the time of construction, an incident report shall be filled out and

submitted to the Superintendent within 24 hours of the incident occurring. Refer to the requirements outlined in Section 8.12 of the EMP (GHD, 2008a).


3.12. Emergency Response at Construction and Operation The potential types of emergency situations that may arise during construction and operation include the following: • Fire / Explosion • Fuel / Oil Spill • Plant Accident • Major Storm Event In the case of a fuel spill or other such emergency, members of the existing Cocos Island Emergency Service Organisations may be called upon for assistance. A list of emergency contact numbers are listed in Table 3.2.

Table 3.2 Emergency Contact Telephone Numbers for the Cocos (Keeling) Islands

Organisation Contact Telephone Number

Environment Officer Indian Ocean Territories (08) 6364 6680

West Island Emergency Number (Volunteer and Rescue Services) (08) 9162 7777

Home Island Emergency Number (Volunteer and Rescue Services) (08) 9162 7788

Cocos (Keeling) Islands Federal Police 000 or (08) 9162 6600

Cocos (Keeling) Island Hospital (08) 9162 6655

Parks Australia North (08) 9162 6678

The following actions are required to ensure that Wylie and Skene are prepared to handle an emergency situation during construction: • Wylie and Skene are committed to providing the necessary resources to respond to any

emergency spill situation which may occur, in a way that will minimize the potential impacts on the environment;

• Wylie and Skene shall develop an Emergency Response Plan to make certain that it responds to any incidents that may impact on the environment and that all personnel including sub-contractors are inducted in its application. This will include a spill clean up plan for dealing with fuel or oil spills such that the risk of pollution of the marine environment is minimized;

• Wylie and Skene shall provide a manifest of any potential water pollutants used for the construction of the works and shall provide details of clean up and disposal procedures for each type where applicable;

• Wylie and Skene shall have a spill response kit, fire extinguisher and other emergency response equipment fully maintained and readily available, with appropriate absorbing pads and booms will be stored at all times;

• As part of the spill response an empty tank with vacuum pump and hose for collection of spilt liquid will be located nearby; and

• Contact phone numbers for relevant authorities are checked and updated monthly.


4. Review Procedure

4.1. Reporting requirements Weekly reports outlining the results of the marine monitoring and any exceedances and subsequent actions, will be submitted by the contractor to the superintendent. Reporting of turbidity, light and sedimentation data is to happen within 7 days of downloading loggers and/or finishing a data collection cycle (one week), or as agreed with by the Superintendent. Reporting of seagrass/macroalgae and coral health is to happen within 10 days of completing each period of monitoring, or as agreed with by the Superintendent. These reports will be forwarded to the regulatory authorities by the Superintendent. Quarterly groundwater monitoring reports will be submitted by Wylie & Skene to the Superintendent within two weeks of completion of each period of monitoring. The Superintendent will submit the reports to DEWHA and DEC. Documentation of the silt curtain inspections will be forwarded to the Superintendent on a weekly basis for the first two weeks of deployment. Thereafter reports will be forwarded on a fortnightly basis. The Complaints register will be reported by Wylie & Skene to the Superintendent within 48 hours of receiving a new item. If there is more than one new item per week, the Complaints Register may be submitted on a weekly basis. The Contractor will issue incident reports to the site Superintendent (GHD) within 20 hours of the incident occurring. The site Superintendent will forward the reports of any environmental incidents to DEWHA within the 24 hours of the incident occurring. The incident report is to include details of the incident and any additional measures proposed to be taken.


5. Baseline monitoring

5.1. Baseline survey The baseline survey was undertaken during February 23rd to March 1st 2009. The results are appended in Appendix E.


6. Dredge Management Plan

6.1. Water quality management parameters

6.1.1. Introduction The material to be dredged consists almost entirely of calcium carbonate (99.9%) with a high silt content of approximately 20% (GHD, 2008a). Silt is defined as particles less than <75 μm in diameter (GHD, 2008a). Due to this high silt content, and the aim of the project to contain as much of the dredged material as possible for land reclamation purposes, the plume is expected to consist almost entirely of fine calcium carbonate particles less than 75 μm. Such particles are likely to mainly stay in suspension rather than settle out due to the combined effect of their small size and the waves and currents at Rumah Baru. Predominant trade winds from the east-south-east are expected to push the plume inshore and prevent it from spreading into the lagoon, while predominant along-shore currents are expected to disperse the plume northwards where it is expected to exit the lagoon at the northern tip of West Island (Kench, 1994; DAL, 1999). Wind waves are expected to act to keep the finer material in suspension. The fine calcium carbonate particles are expected to create a milky white plume with relatively high turbidity readings but with low total suspended solid loads. The primary impact of plume will be increased light attenuation; however smothering of biota is also considered a potential risk. The highest light reduction is expected in the seagrass/macroalgae meadows inshore and northwards from Rumah Baru. A lower density plume is expected to extend to the coral bommies offshore from Rumah Baru. There is some risk of smothering of the coral bommies by the fine particles; due to the northwards moving water the plume may be ‘forced’ past the bommies, trapping fine particles on the surface of the corals. This will in particular be the case where mucous production is excessive.

6.1.2. Monitoring parameters It is proposed to monitor four key oceanographic parameters, and three key water quality parameters, along with basic recordings of turbidity and plume characteristics, which together will provide contextual information, document the dredging activities, record the extent of the sediment plume and form the backbone of the construction monitoring programme. The proposed parameters are as follows:

Plume characteristics (Section 6.1.3): • Source of plume • Turbid plume direction and extent

Atmospheric and Oceanographic parameters (Section 6.1.4): • Wind speed and direction; • Wave direction, height and frequency; • Swell height and frequency; and • Tidal information.

Water quality parameters (Section 6.1.5): • Daily turbidity profiles; • Light; and • Sedimentation. This information will be used to monitor the plume characteristics, extent and density at sites of sensitive habitat. Trigger levels for turbidity, and thresholds for light and sedimentation at fixed sites will be used to implement mitigation and management measures, when needed, to protect the marine environment at Rumah Baru from adverse impacts caused by the construction and dredging. The turbidity trigger levels and sedimentation and light thresholds are discussed further in Section 6.2.2 and 6.2.3.


6.1.3. Plume characteristics

Source of plume A daily record will be kept of the construction activities being carried out and the activities generating turbidity.

Turbid plume direction and extent The conditions of approval required observations every two days, it is intended however that the location of the plume will be observed daily (morning – after construction has been under way for at least three hours) from an elevated site at Rumah Baru of appropriate location, most likely from a ‘cherry picker’ or scaffold platform, allowing an overview of the construction operations. The extent and location of the plume will be recorded, and photographs taken as appropriate for contextual information. A record will be kept of plume direction and extent as visible from this vantage point. Plume observations will be undertaken with the naked eye using polarised sun glasses. A polarised filter will be used for taking photographs, if the conditions are favourable. This will mainly depend on the angle of the sun, but also the degree of cloud cover. If the conditions are unfavourable for polarised filter photography, photographs will be taken using only a sky light filter. If needed, binoculars will be used for plume observations, however the project area is sufficiently close to land to obtain a good view from shore. The daily observations from the elevated platform will allow a rapid assessment to be made regarding the daily placement of the targeted water quality sampling sites (see Section 6.1.4), and the appropriateness of the fixed seagrass/macroalgae and coral monitoring sites. In addition, a check can be carried out that turbidity is not spreading to other biota elsewhere in the lagoon.

6.1.4. Atmospheric and oceanographic measurements Oceanographic and atmospheric parameters will be recorded once daily (morning). Oceanographic parameters may be observed from a boat or from the elevated location, as mentioned above. In addition, it is proposed to obtain turbidity profiles at five targeted water quality sites, which will be determined each morning in relation to the plume. This will ensure that the turbidity of the densest part of the plume can be monitored at all times, including when the plume does not overlap with the coral and seagrass/macroalgae monitoring sites. This data will be collected for contextual information.

Atmospheric parameters The wind speed and direction will be noted morning and afternoon on the daily recording sheet (Appendix D) on site and this information will be subsequently supplemented in reports with data from the meteorological station at Cocos (Keeling) Island.

Oceanographic parameters The oceanographic parameters at Rumah Baru will be recorded once daily during the morning observation of the plume extension. The wave direction will be recorded by visual observation. The wave height will be estimated by eye, and the frequency will be recorded by using a stop watch to count how many waves in a minute, or seconds between swells. Swell height and frequency will be recorded as for wave height and frequency. The sea-state will be recorded daily according to the Beaufort scale, as modified by AIMS (Table 6.1). The assessment of sea-state will be based on qualitative observations of wave height and sea conditions and related to the measured wind speed, as detailed in Table 6.1. Tidal information will be obtained from published tables and ultimately supplemented with actual data from the tide gauge at Home Island.


The current speed and direction will be recorded using a drogue made of a plastic bag 95% filled with water and sealed so it just floats. It will be released in about 0.5 – 1 m of water and timed for 1–5 minutes (less time needed if current is strong), or when it washes ashore. The distance between the release point and the retrieval point is measured by tape or by pacing, depending on distance travelled.


Table 6.1 Beaufort wind and sea state scale, as modified by AIMS for the long-term monitoring programme

Beaufort AIMS Wind speed (m/s)

Description Wave height (m)

Sea conditions

0 <0.3 Calm 0 Flat

1 0.3-1.5 Light air 0.1 Ripples without crests

2

Calm

1.5-3.3 Light breeze 0.2 Small wavelets. Crests of glassy appearance, not breaking

3 Slight 3.3-5.5 Gentle breeze 0.6 Large wavelets. Crests begin to break; scattered whitecaps

4 Moderate 5.5-8.0 Moderate breeze 1 Small waves

5 8.0-10.8 Fresh breeze 2 Moderate (1.2 m) longer waves. Some foam and spray.

6 Rough

10.8-13.9 Strong breeze 3 Large waves with foam crests and some spray

7 13.9-17.2 High wind, Moderate gale, Near gale

4 Sea heaps up and foam begins to be blown in streaks in wind direction

8 17.2-20.7 Fresh gale 5.5 Moderately high waves with breaking crests forming spindrift. Streaks of foam

9 20.7-24.5 Strong gale 7 High waves (6-7 m) with dense foam. Wave crests start to roll over. Considerable spray

10 24.5-28.4 Whole gale, storm

9

Very high waves. Large patches of foam from wave crests give the sea a white appearance. Considerable tumbling of waves with heavy impact. Large amounts of airborne spray reduce visibility

11 28.4-32.6 Violent storm 11.5

Exceptionally high waves. Very large patches of foam, driven before the wind, cover much of the sea surface. Very large amounts of airborne spray severely reduce visibility

12

“Very rough” (not specified by AIMS)

≥32.6 Hurricane-force ≥14 Huge waves. Sea is completely white with foam and spray. Air is filled with driving spray, greatly reducing visibility

6.1.5. Water quality parameters

Turbidity Turbidity measured in Nephelometric Turbidity Units (NTU) is proposed as the main proxy measurement of the suspended particles forming the plume. A handheld turbidity meter will be used to obtain turbidity profiles by recording continuously while slowly lowering the meter down through the water column to just above the sea floor. The meter will also record depth, temperature, dissolved oxygen, and salinity, as outlined in Table 6.2. To obtain a single turbidity value for each monitoring site, turbidity will be averaged over the water column-depth. Immediately on completion of the observations from an elevated location onshore, the daily turbidity measurements will be obtained at the six fixed seagrass/macroalgae sites off Rumah Baru (five impact sites and one reference site), and the five fixed coral sites off Rumah Baru (four impact sites and one reference site). As described in Section 6.1.4 turbidity profiles will also be obtained on five flexible sites within the plume. Daily profiles will also be obtained at background sites as determined by visual observations from the elevated platform, and at the stilling pond discharge point for contextual information.

Light Light is proposed to be logged with stationary Odyssey light loggers. As the depths at the seagrass/macroalgae sites are insufficient for logger array deployment, single light loggers will be deployed at the bottom at the five seagrass/macroalgae monitoring sites off Rumah


Baru, and both reference sites (S8 off Rumah Baru and S9 off Home Island). These loggers will be set to record average light intensity readings at 5 minute intervals. Prior to deployment the loggers will be calibrated to ensure that readings can be converted to PAR (μEm2/s). The light loggers will require cleaning of the sensors approximately every 1-3 days, depending on the degree of fouling and/or sedimentation. Cleaning will be undertaken by a person on snorkel immediately after the turbidity profile has been obtained at the sites off Rumah Baru. The reference site off Home Island will not be subjected to the dredge plume and the light logger here will be cleaned at a minimum during the seagrass/macroalgae monitoring (Section 6.4) and more often if it is found necessary and logistically practicable.

Table 6.2 Logger specifications

Water Quality Meter Light logger

Brand Parameter Brand Parameter

Turbidity (NTU) (range: 0-1000 NTU)

Dissolved oxygen

Salinity

Temperature

Conductivity

Horiba1

Depth

Odyssey

PAR (Photosynthetic Active Radiation: 400-700 nm)

1Troll 9500 used during the baseline survey had turbidity recording accuracy range of 0-2000 NTU

Sedimentation Sedimentation may occur as intensive events or lighter, prolonged events, with particles settling and resuspending according to the sea-state and currents. In relation to impacts, the key is to detect persisting settled sediments which are not resuspended soon after settlement. As sedimentation is a difficult parameter to measure due to continuous settling and resuspension in various sea states and plume concentrations, it is proposed that sedimentation is assessed by direct observations. It is proposed to monitor sedimentation at the coral monitoring sites by underwater observation using a qualitative scale of percent of the entire colony smothered with sediment, as well as the percent of the entire colony covered in mucous. Mucous production has previously been reported for the corals at Rumah Baru to free themselves of settled sediments (Jo Buckee, pers. com. January 2009; pers. obs. February 2009), and was observed also during the baseline survey in February 2009. During the baseline survey observations were made of adjacent bommies, one fully covered in mucous and the other completely clean, indicating that mucous is produced over a period of time then shed completely at some point, possibly linked to the sediment load. The presence of mucous and sediment is a natural event and not necessarily indicating that adverse impacts to the coral will occur (such as bleaching and death). To identify if the sediment plume is causing increased mucous production and trapping of particles on the bommies, the bommie sedimentation and mucous observations will be compared through time within each site, and also compared to the Rumah Baru reference site (CR1). Increased sedimentation can plausibly be attributed to plume effects when 1) increased mucous production within a site over time is observed, measured as an increase in the average percentage of the bommies covered in mucous, and 2) an increase in mucous production is not observed on the reference site (CR1). The sediment and mucous observations will be accompanied by still photographs of the coral bommies by: top view (1 photograph) and side views (4-5 photographs). However due to the poor visibility at the sites off both Rumah Baru and Home Island photographs may not be of sufficient clarity to adequately record sedimentation and mucous production, and photographs are expected to provide contextual information only. This will especially be the case when the plume drifts over the coral sites off Rumah Baru. Likewise, sedimentation at the five seagrass/macroalgae monitoring sites and the Rumah Baru seagrass/macroalgae reference site (S8) is proposed recorded through visual


observations to assess the degree of sedimentation in the seagrass/macroalgae beds. Quadrants will be randomly deployed, as described in Section 6.4.3, and the percent cover of Thalassia hemprichii and Caulerpa spp., respectively, will be recorded along with the percent smothering.

6.2. Water quality monitoring programme

6.2.1. Management framework The water quality programme will consist of:

1. Daily turbidity profiles obtained on the coral and seagrass/macroalgae sites (impact and reference) off Rumah Baru.

2. Comparison of turbidity readings against turbidity trigger levels (refer below) 3. Exceedence of turbidity trigger levels will trigger (1) construction mitigation measures

to decrease the plume, and (2) monitoring of sedimentation (on coral sites) and light (on seagrass sites)

4. Exceedence of sedimentation and/or light threshold levels will trigger management measures (stop plume producing activity).

5. Set procedures for re-starting the activity(ies) 6. As set out in the approved EMP, the turbidity trigger levels will be subject to review

during the program, and refined in consultation with DEWHA (agreement in writing needed) in the event that they are found to be unduly conservative or not protective enough.

The broad framework is shown in Figure 6.1. The specific monitoring programmes for corals and seagrass are discussed in more detail in Section 6.2.2 and Section 6.2.3 respectively. Turbidity trigger levels for corals and seagrass have been set for rapid mitigation response when excess turbidity is created. Because an exceedence of these turbidity trigger levels also trigger further investigation (smothering, light levels) persistent plume production can be stopped before impacts occur. This is ensured through threshold levels for sedimentation (corals) and light (seagrass). If these thresholds are exceeded then the plume producing activity is stopped, with set re-start procedures in place. Once an exceedence of the turbidity trigger levels is recorded on any three consecutive days, each step in the process, as outlined in Figure 6.1 and detailed further in Figure 6.2 and Figure 6.3, will be implemented as soon as possible. The process from the exceedance to the implementation of any management measures is expected to take no longer than 48 hours. If this process has a duration of more than 48 hours (for example, due to equipment failure), the turbidity causing activity will cease immediately until it is determined that the threshold levels have not been exceeded. If they have been exceeded, standard restart procedures will apply. Turbidity levels have been developed individually for corals and seagrass, reflecting the use of turbidity as proxy for sedimentation risk (corals) and light climate (seagrass). Likewise, the thresholds differ between biota type with sedimentation used for corals, and light for seagrass, reflecting the different pathways of impact. The thresholds comprise of a “value” component and a “duration” component and are discussed further in Section 6.2.2 and 6.2.3. Exceedances of turbidity trigger levels will be reported daily to Wylie & Skene for immediate instigation of mitigation measures (same day). Wylie & Skene will also be kept informed of approaching exceedence of threshold levels (sedimentation, light) as an early warning for the necessity of implementing management measures. All monitoring results will be reported on a weekly basis to the site superintendent. In the event that threshold values (sedimentation, light) are about to be exceeded for the threshold duration, the site superintendent will be informed immediately and Wylie & Skene will supply the proposed management measure(s) to the superintendent. In the event of equipment failure of the handheld turbidity meter, a secchi disk will be used until such time as a replacement meter can be obtained. Secchi disk readings will be taken


contemporaneously with turbidity readings during the surveys so that in the event of equipment failure, the measured secchi depths can be converted to light extinction with some confidence until such time as replacement equipment can be obtained or the repairs effected.

Figure 6.1 Monitoring, mitigation and management framework for turbidity creating activities

6.2.2. Coral monitoring

Background The primary stressor for corals during dredging is sedimentation. Turbidity is proposed as the proxy measurement defining when such loads of solids are present in the water column that settling out could potentially cause an impact. As the risk of settling particles varies with sea-state, specific turbidity trigger levels are proposed for a range of conditions, as described in Koskela et al. (2002).

Turbidity trigger levels and sedimentation threshold levels The turbidity trigger levels and sedimentation threshold levels are outlined in Table 6.3, including the action in the event they are exceeded. At present the turbidity trigger levels are interim and will be refined when baseline data becomes available (see below) and as the dredging and construction program progresses (see Section 6.2.4). During the baseline study measurements of turbidity and TSS were undertaken to obtain a relationship between these two parameters, based on the fine sediments (silt) which will produce the plume during dredging and construction. This is discussed in more detail in Section 4 in Appendix E. The turbidity trigger levels in Table 6.3 will be refined prior to dredging commences by relating the trigger levels to literature values for TSS tolerance for massive Porites species. Calculations will be undertaken to assess the TSS concentrations required for an unacceptable sediment layer to form in the event the particles settle out. These concentrations will be relative to the sea-state, with a risk based approach of settling of fines in various conditions. The refined thresholds will be related to the published values in Koskela et al. (2002) and other relevant literature values, as summarised by Gilmour et al. (2005) and discussed by Fabricius (2005). The sedimentation threshold levels are based on local observations (Appendix E) and the premise that Porites can handle sedimentation accumulation for ‘days’ (Gilmour et al., 2005).


Coral monitoring programme A detailed flowchart of the coral monitoring programme is shown in Figure 6.2. Exceedence of turbidity trigger levels on any one day will trigger mitigation measures to be put into place to reduce the turbidity. In addition, an exceedence of the turbidity trigger levels for three consecutive days will trigger visual inspection and assessment of the amount of sediment present on the corals, including the degree of mucous secretion response by the corals, indicating the persistence of the settled sediment. Exceedence of a sedimentation threshold observed on any one day will trigger management measures to be put into place (stop activity). The re-start criteria involve obtaining turbidity profiles every 3 hours until the plume has cleared and the turbidity is below the turbidity trigger levels.

Table 6.3 Coral turbidity trigger levels and sedimentation thresholds and action criteria

Condition1 Turbidity trigger

level (NTU)2 Action Sedimentation

thresholds3 Reaction

Calm 6

Slight 15

Moderate 30

Rough 60

Very rough 120

Any 1 day: implement mitigation measures (Section 6.3); Any 3 consecutive days: undertake sedimentation assessment

>50% sediment cover for more than two weeks; or 50-80% sediment cover for more than 1 week; or 100% cover for more than 4 days.

Implement management measures (Section 6.3).

1As per Table 6.1 2From Koskela et al., 2002 3Expressed as the average of 10 samples (marked bommies) within each site


Figure 6.2 Proposed water quality monitoring programme for coral

6.2.3. Seagrass monitoring

Background The natural process of Rumah Baru includes high variability in presence of both seagrass and the dominant macro-algae species of Caulerpa. For example, events occur regularly where large volumes of seagrass wrack from the south-east area of the lagoon are washed into the nearshore and onto the shore at Rumah Baru. Previous studies at Rumah Baru have shown that both seagrass and macro-algae exhibit high variability in occurrence both temporarily


and spatially, indicating that both Thalassia hemprichii and Caulerpa spp. can be present and absent between surveys, and have a high capacity for recolonisation. As set out in the EMP, the primary stressor for seagrass during dredging will be light deprivation from suspended solids. It is proposed to use turbidity measurements as a proxy for reduced light climate. As the light climate at the seabed at a given turbidity level depends on the water depth (more light will be attenuated at greater depths), specific turbidity trigger levels are proposed for various water depths.

Turbidity trigger levels and sedimentation threshold levels The turbidity trigger levels and light threshold levels are outlined in Table 6.4, including the action in the event they are exceeded. At present the turbidity trigger levels are interim and will be refined as the dredging and construction program commences (Section 6.2.4). The light requirements for the Thalassia hemprichii at Rumah Baru has been the subject of previous work (Maunsell 2000, 2003) and previous derived light thresholds are used for the monitoring programme (Table 6.4 and Table 6.5).

Monitoring programme A detailed flowchart of the seagrass monitoring programme is shown in Figure 6.3. As for corals, exceedence of a turbidity trigger level on any given day will trigger mitigation measures to be implemented for immediate plume reduction. Exceedence of turbidity trigger levels for three consecutive days will furthermore trigger a weekly downloading of the deployed light meters (on the last day of a monitoring week). The light intensity from the impact sites will be examined by obtaining average readings for the midday period defined as between 11 am and 1 pm, and a running 30 day mean light intensity obtained (before 30 days have passed, averages will be based on the available data). The running mean will be compared to the threshold outlined in Table 6.4. In the event that the running mean intensity is below the light threshold for 30 days, management measures will be implemented, as set out in Section 6.3. This includes stopping the activity that is causing the excess turbidity, with set re-start procedures in place, as shown in Figure 6.3. Although spare loggers will be taken to site, in the event that light loggers fail, a set of back-up thresholds based on turbidity (measured as NTU) and secchi disk depth will be used, as outlined in Table 6.5. The initial site work will also focus on generating a local relationship between turbidity, light attenuation and secchi disk depth to replace the interim relationship which is based on unpublished results from an intensive dredge monitoring program in Cockburn Sound, WA (Figure 6.4 and Figure 6.5). This program was conducted in calcium carbonate limestone material and generated a fine white plume so the mineralogy of the material is not dissimilar from that expected at Rumah Baru. The value of 35% of reduction of SPAR (being light immediately below the water surface) is very conservative and the fact that secchi disk approximates the seabed at 2.5 m depth is logical as it has been observed that this approximates the observed depth limit for these seagrasses off Rumah Baru on Cocos (Keeling) Islands. The degree of smothering will be assessed by direct observation during the seagrass health surveys (Section 6.4.3) and noted for consideration regarding the protection afforded by the thresholds.


Figure 6.3 Proposed water quality monitoring programme for seagrass


Table 6.4 Seagrass turbidity trigger levels and light thresholds and action criteria

Depth (m) Turbidity trigger level (NTU)1

Action Light threshold level (GHD, 2000)2

Action

0.5 36

1.0 16

1.5 10

2.0 7

2.5 5

Any 1 day: implement mitigation measures (Section6.3); Any 3 consecutive days: undertake weekly light logger download

200 μE/m2*S for 30 days

Implement management measures (Section 6.3)

1 Depth Averaged Turbidity (NTU) (based on interim turbidity-light attenuation relationship as described below) 2 Minimum average midday values, being average of readings between 11 am and 1 pm

Table 6.5 Back-up thresholds for Thalassia hemprichii at Rumah Baru based on turbidity and Secchi in event that light loggers fail

Water Depth at seagrass site (m)

Vertical light attenuation to ensure 35% of SPAR reaches seabed (Kd: ln(m-1))

Depth Averaged Turbidity (NTU) (based

on interim turbidity-light attenuation

relationship below)

Secchi Depth (m) (based on interim

SDD-light attenuation

relationship below)

0.5 2.1 36 0.05

1.0 1.0 16 0.25

1.5 0.7 10 1.0

2.0 0.5 7 1.8

2.5 0.4 5 2.5 (= seabed)


y = 13.654e-3.8055x

R2 = 0.7669

0

2

4

6

8

10

12

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Light attenuation (Kd) (ln/m)

Secc

hi d

isk

dept

h (m

)

Figure 6.4 Relationship used to derive interim Secchi Disk threshold from light attenuation (Kd)

Measure Light attenuation vs. turbidity AMC dredge program 2000

y = 18.967x - 3.4389R2 = 0.7353

0

2

4

6

8

10

12

14

16

18

0 0.2 0.4 0.6 0.8 1 1.2

Light attenuation (Kd)

Turb

idity

(NTU

)

Figure 6.5 Relationship used to derive interim turbidity threshold from light attenuation (Kd)

6.2.4. Turbidity trigger level review The objective of the turbidity trigger level review is to investigate if the turbidity trigger levels are appropriate indicators of suspended solids in the water column at concentrations high enough to cause smothering of corals to the degree where they can no longer clear themselves, and/or block light for the seagrass so that the light threshold is exceeded. The monitoring approach is therefore to set conservative turbidity trigger levels, which will most likely trigger coral and seagrass smothering surveys and light logger downloads several times


a week. After three weeks sufficient information should be available to adjust the turbidity trigger levels to more accurately reflect the risk of smothering and light deprivation. As set out in the EMP, the appropriateness of any turbidity trigger levels or durations will be assessed during the dredging and they may be altered (with the approval of the Site Superintendent) if they are found to be not protective or too conservative. It is proposed to review the turbidity trigger levels every three weeks in the beginning of the dredging and land reclamation programme, based on the water quality data, the biota observations, and the health surveys (Section 6.4). Such reviews, and proposed improvements, will be discussed in the weekly reports as appropriate. Written agreement on the use of revised turbidity trigger levels will be needed from DEWHA.

6.3. Mitigation and management measures The management of turbidity creating activities include the following activities: • Dredging • Stilling pond return water • Filling of geotubes (large) and geobags (small) • Land reclamation return water The management will be undertaken through mitigation measures and management measures, as described in further detail below. Both mitigation measure and management measures will be implemented as soon as practicably possible on the same day that an exceedence has occurred. The daily plume observations undertaken in the morning of each day (Section 6.1.3) will indicate which activity is responsible for the elevated turbidity (i.e. dredge cutter head, stilling basin outlet, geotube/geobag filling, or land reclamation return water). A number of or all mitigation measures and management measures will subsequently be implemented according to which activity is causing the excess turbidity.

6.3.1. Dredging

Mitigation measures: • Deployment of silt curtains around the work area; • Deployment of silt curtains around southern end of bommie field (or as appropriate) to

deflect the plume; • Relocate the dredge (limited option due to the small dredge footprint); • Cease dredging for the day (if late afternoon); and • Adjust the dredging method.

Management measure Stop dredging

6.3.2. Stilling pond return water

Mitigation measures • A silt curtain will be deployed around the return water outlet at all times; • If site conditions are adverse the silt curtain may be deployed on the inside of the stilling

pond; • Deploy a second silt curtain around the return water outlet • Slurry will be pumped to the back of the stilling pond to maximise settlement in the

several basins prior to discharge; • To control the flow rate of the return water the height of weir wall of the settling ponds

can be adjusted to regulate flow by adding or removing geobags; and • The build-up of fines in the stilling ponds will be inspected daily, and the fines relocated

on a per-needs basis. • Additional stilling ponds may be constructed internally in the stilling pond area to reduce

turbidity.


Management measure: Stop the return water flow by adding geobags to the weir walls of the stilling ponds for settlement of particles prior to recommencing discharge.

6.3.3. Land reclamation

Mitigation measures; • Deploy silt curtains around the return water outlet; • Deploy silt curtains on the inside of the land reclamation boundary at the return water

outlet site(s); • Regulate the return water outlet flow rate to maximise settling of particles; • Regulate the inflow of slurry from the pipe to minimise turbulence inside the land

reclamation boundary; • Use the coarsest dredge material at the perimeter of the land reclamation area, and the

finer material in the centre; • Install internal baffles or walls of geotextile fabric to increase settlement; and • Maximising the use of coarse material for the reclamation of the island with fine material

going to the stilling basin.

Management measure: Stop the return water outlet flow for settlement of particles prior to recommencing discharge.

6.3.4. Filling of geotextile tubes and bags The filling of the large geotextile tubes in situ is not expected to create any significant turbidity by particles exiting through the geofabric. As discussed in Section 2.2.6, the geotextile fabric has a pore size of less than 75 μm and is furthermore coated with a layer of vandal deterrent material on either side, further decreasing the overall pore size of the material. However, some turbidity is expected from incidental spillage during filling mainly through the relief valve on the tubes, and possibly from between the pipe and the filling hole. Due to their size, the large geotubes can only be filled in situ at the seabed, where they will remain after filling is complete as the foundation of the island perimeter.

Mitigation measures: • Deployment of silt curtains around the filling area of the geotubes and bags; • If conditions too rough, stop work until conditions are favourable for silt curtain

deployment. • Reduce the filling rate. • Filling the geobags on a barge, where spillage can be controlled and ‘overflow’ from the

filling hole is likely to occur to a lesser extent (not applicable to the geotubes); and • Filling the geobags on the reclaimed land (once the island level is sufficient) (not

applicable to the geotubes).

Management measure Stop filling geotextile tubes or bags.

6.3.5. General review of methods Throughout the construction period an ongoing review of the major sources and activities of turbidity will be undertaken. Regular discussion with staff will be undertaken on means of reducing turbidity by altering or refining the construction methods on a needs basis, as appropriate based on the outcome of the water quality monitoring programme.

6.4. Monitoring of biota

6.4.1. Objective Monitoring of coral and seagrass/macro-algae is proposed prior to, during and after the end construction. The objective is to verify that no impacts occurred due to dredging and construction activities.


6.4.2. Coral Monitoring The occurrence of corals at Rumah Baru differs to that of a reef slope coral garden in that large bommies of mainly one genus (Porites) are interspersed in a sandy habitat, as shown in Figure 6.5 (Maunsell 2003). The survey method stipulated in the EMP of belt transects along eight fixed monitoring sites (GHD, 2008a) is therefore not considered practical for the specific coral assemblages at Rumah Baru. Due to the absence of continuing coral cover, it is proposed to instead monitor entire bommies separately and treat each of these as an individual sample. It is proposed to survey ten bommies at four impact sites, and ten bommies at two reference sites. During the baseline survey one reference site was set south of Rumah Baru, and one site off Home Island. This is discussed in more detail in Section 2.2 in Appendix E. It is possible that additional coral monitoring sites may need to be introduced if the plume is found to extend beyond the coral survey area, potentially impacting on corals elsewhere in the lagoon. For this reason two potential sites were identified between Rumah Baru and the jetty at the northern tip of West Island (Section 2.2.3 in Appendix E). The coral sites shown in Figure 6.7 were assessed during the baseline survey 2009, and are proposed to be monitored immediately before dredging starts (i.e. June), every 3 weeks during dredging and other turbidity producing activities, immediately upon completion and again three months post turbidity producing activities. The purpose is to ensure that no unacceptable and long term impacts were caused by the construction and dredging activities. Data collection on the reference sites will be used in this assessment. The proposed parameters are: • % live cover • % bleaching • % sediment cover • % mucous cover • % mucous cover with sediment particles In addition, for the purpose of contextual information, the general health status will be described by comments, and the overall health of the coral bommie assigned a status based on a subjective scale of 1 to 5, as described in Maunsell (2003).


Figure 6.6 Location of coral bommies, including inside the proposed approach channel (GHD, 2008a)


6.4.3. Seagrass/macroalgae Monitoring The seagrass is proposed to be monitored as outlined in the EMP with additional parameters included to match the methods used during the baseline studies from 1996 onwards for continuation of existing data sets. This method has been assessed for statistical power and modified to suit the local conditions (Prince, 2003). The full set of seagrass sites proposed in the EMP is shown in Figure 3.1 in Appendix E. A subset of five is proposed as seagrass/algae monitoring sites for the monitoring programme, as shown in Table 6.6 and Figure 6.7. In addition, the southern most site (S8) is proposed used as reference site, as discussed in further detail in Section 3.1.2 in Appendix E. An additional reference site was set off Home Island during the baseline survey 2009 for the purposed of identifying potential lagoon-wide impacts (Figure 6.7). For the seagrass monitoring it is proposed to collect data from 30 random quadrats at each of these seven seagrass/algae sites, using the methods developed previously (Maunsell, 2003). The seagrass sites shown in Figure 6.8 were assessed during the baseline survey 2009, and are proposed to be monitored immediately before dredging starts (i.e. June), every 3 weeks during dredging and other turbidity producing activities, immediately upon completion and again three months post turbidity producing activities. The purpose is to ensure that no unacceptable and long term impacts were caused by the construction and dredging activities. Data collection on the reference sites will be used in this assessment. The proposed parameters are: • % cover of live seagrass (total) • % cover of live seagrass (smothered) • % cover of live Caulerpa spp. (total, all species) • % cover of live Caulerpa spp. (smothered) • biomass rank as set during the baseline survey 2009 relating to the total wet weight of all

species present within in each quadrant

Table 6.6 Indicative sampling locations for corals (‘c’) and seagrass (‘s’). Coordinates are given in UTM47 GDA94

Sample Point Easting Northing Sample Point Easting Northing

CH1 264078 8655378 S2 263796 8655347

CH2 264021 8655467 S3 263692 8655517

CH3 264064 8655594 S5 263563 8655846

CH4 263942 8655821 S6 263925 8655088

CR1 264358 8655125 S7 263963 8654881

CR2 271049 8659058 S8 264026 8654710

CH51 263669 8656964 S9 271426 8659155

CH61 263549 8656605 S101 263488 8656575

S111 263460 8656396 1Potential impact site to the north of Rumah Baru (not currently included in the monitoring programme)


Figure 6.7 Proposed monitoring and reference sites for corals


Figure 6.8 Proposed monitoring and reference sites for seagrass


6.5. Coral Spawning Monitoring

6.5.1. Background The scleractinian corals of the west coast of Australia reproduce each year in mass spawning events following the March and April full moons (Simpson 1985, 1991; Simpson & Masini 1986 in: Taylor and Pierce, 1991). Mass coral spawning events have been observed on the Australian west coast on reefs several hundred kilometres apart (Simpson, 1988), though there is also evidence that spawning may be offset slightly between locations (Taylor and Pierce, 1999). However, it is widely accepted that mass spawning events take place along the entire West Coast in the autumn each year (March/April), much like the mass spawning event on the Great Barrier Reef in spring (and to a lesser extent autumn) each year. Based on personal experience and anecdotal evidence, coral spawning in the Cocos (Keeling) Islands is most likely to be in January or February and finished by the end of March (Jo Buckee, pers. com., January 2009). Observations of coral spawning were made by Ismail McCrae (Parks Australia, Cocos (Keeling) Islands) in the first half of February 2009, with observations by Parks Australia employees in previous years typically in January to March. Previous observations of spawning events on Cocos (Keeling) Islands is discussed in further detail in Section 2.4 in Appendix E. Mortality events caused by “red tides” have historically been recorded in March at Cocos (Keeling) Islands during at least two different years. This phenomenon was considered by AIMS to be likely attributed to coral spawning in Cocos (Keeling) Islands (Woodroffe and Berry, 1994). Negative impacts in the lagoon from these events have been speculated to be caused by mass coral spawning at a time of poor water circulation, similar to the event described by Simpson (1993) on the Australian West Coast (Woodroffe and Berry, 1994). Studies undertaken in Mermaid Sound in the Dampier Archipelago recording the autumn mass spawning event did not detect any participation by the Porites species occurring here, nor were any sperm or eggs observed inside the polyps (Stoddart and Gilmour, 2005). This was also the case when Simpson (1988) undertook extensive studies in the Dampier Archipelago in November and March 1984 and March 1985. No gametes were found in any of the three Porites species examined and they did not appear to partake in the mass spawning event. Recent studies have shown that Porites in the Dampier Archipelago spawn en mass in November/December (Jim Stoddart, pers. com., February 2009). The exact species of the Porites occurring at Rumah Baru forming the massive bommies is not known, however it is most likely either P. lobata or P. australensis, as both have been reported previously as common in the Cocos (Keeling) Islands (Veron, 1994). The baseline survey coral samples are currently undergoing identification and the species will be reported in the baseline report. Both the likely species of Porites (P. lobata or P. australensis)are gonochoic broadcast spawners (Neves, 2000), and the bommies off Rumah Baru would therefore most likely spawn synchronously (Oliver and Babcock, 1992), though not necessarily during the mass spawning event predicted for early2009. It is considered likely that they will already have spawned in November/December, as for Porites in Mermaid Sound.

6.5.2. Methodology of anticipation of coral spawning To ascertain that the Porites bommies at Rumah Baru are not spawning at the time of dredging and construction, daily observations of the plume and hydrographical conditions (Section 6.1) will include observations for coral spawn slicks. During the fortnightly coral monitoring (Section 6.4.2) observations will be made of abnormal fish feeding behaviour. As mass-spawning on Western Australian reefs seem to occur around six to ten nights after the full moon (in March and/or April) (Simpson, 1985 and Babcock et al., 1994 in: Stoddart and Gilmour, 2005), the lunar cycle will be recorded and targeted snorkel dives undertaken up to and at these critical times to observe if spawning is occurring (Table 6.7). In the event coral spawning is observed, dredging and return water outlet flow will be stalled until one day after the spawning event has terminated.


Table 6.7 Predicted coral spawning and observation dates

Full moon (2009) Potential spawning Observations to be undertaken daily

April 9 April 15-19 April 13-21

May 9 May 15-19 May 13-21

June 7 June 13-17 June 11-19


7. Removal of coral bommies

7.1. Bommies for removal As detailed in the EMP (GHD, 2008a), five significant coral outcrops were noted within the proposed channel, and relocation of these will be undertaken prior to dredging. The bommies were selected according to a set of criteria for ‘significant’ (GHD, 2008a), and were described as follows: • One outcrop exceeding 5 m2 in area located on the northern boundary of the dredge

channel approximately 2/3 of the way along the dredge channel (250 m from the berth basin). Referred to as “Bommie A” in Figure 7.1.

• One outcrop approximately 4 m2 in area located on the southern boundary of the dredge channel approximately 1/3 of the way along the dredge channel (110 m from the berth basin). Referred to as “Bommie B” Figure 7.1.

• Three outcrops in the 3 to 4 m2 range located close to each other on the northern boundary of the berth basin near the intersection with the start of the dredge channel. Referred to as “Bommies C, D, E” in Figure 7.1.

The location of these bommies were shown in the EMP (Figure 6.6), however the coordinates were not supplied. The baseline survey identified a number of significant bommies, which are likely to be the ones identified in Figure 6.6. Prior to dredging and following accurate marking of the channel a further sweep will be undertaken of the channel, and the bommies within the channel relocated as described in Section 7.2.

7.2. Methodology for removing the bommies Removal of the coral outcrops are proposed to be undertaken prior to the start of construction by lifting or dragging. The bommies are believed to be shallow rooted and not firmly anchored into the underlying limestone material. This was confirmed for the smaller bommies during the baseline survey in February 2009, and is believed to be the case also for the larger bommies (Section 2.5.5 in Appendix E). For relocation purposes it is proposed to harness the bommies using cushioned straps connected to a stationary barge at low tide. The rising tide will lift the bommies free of the substrate and float it for relocation. In the event this method proves unmanageable due to unforeseen circumstances, the harness may be used to ‘drag’ the bommies loose and relocated them this way. During the previous channel realignment at Cocos (Keeling) Islands, some bommies were found to be so firmly anchored that surface operated pneumatic tools were needed to free them from the underlying substrate. Among other methods, an underwater operated chisel and chain saw were used (Greenacre et al., 2002). It is not anticipated that such measures will be needed for the current project; however should the bommies be firmly rooted it may not be possible to relocate them without damaging them and alternative solutions will be sought and implemented if practicable. Subject to the findings when bommie relocation commences, all five bommies will be moved out of the channel prior to dredging. Damage to bommies is a consequence of all methods of relocation, with small areas often separating with the stresses of the lifting/dragging. However, these Porites dominated bommies are massive “boulder” type structures, not delicate staghorn or foliose coral structures. Thus while some damage can be expected, the overall integrity of the bommie as a coral structure is not expected to be reduced to a point where the bommie is no longer viable as habitat. However, more damage to surrounding corals outside the proposed channel may occur in the relocation process than would be the case if the bommies in the channel were removed rather than relocated. If this is found to be the case, one or more bommies in the channel may be removed all together rather than relocated to avoid excess damage to other coral bommies.


Figure 7.1 Location of bommies proposed for removal prior to dredging


8. Environment team

8.1. CEMP and monitoring The CEMP (this document) was written by Marianne Nyegaard (Oceanica) with input from Mark Bailey (Oceanica) and Jo Buckee. Both Jo Buckee and Mark Bailey have been involved in the Rumah Baru environmental monitoring and assessment since 1997 when they were both employees of Halpern Glick Maunsell. Marianne Nyegaard, Jo Buckee and Mark Bailey all have considerable experience in the assessment and monitoring of dredging impacts including coral, seagrass and water quality monitoring. The baseline monitoring in February 2009 was undertaken by Marianne Nyegaard, Jo Buckee and Sarah Scott (Oceanica). At this stage it is planned that Marianne Nyegaard will remain as Project Manager, with support from Sarah Scott and Mark Bailey as Project Director. However, as availability or health can be an issue for longer deployments, staff for monitoring during dredging and land reclamation may be drawn from a wider pool of suitably experienced and qualified scientists . Oceanica’s capability statement and the resumes of scientists that are suitably qualified and experienced to undertake the monitoring are included in Appendix F.


9. References Babcock, R.C., Wills, B.L. and Simpson, C.J., 1994. Mass spawning of corals on a high

latitude coral reef. Coral Reefs, 13: 161-169.

DAL, 1999. Investigations for the proposed freight and passenger facilities at Rumah Baru (Cocos Islands). 1999 annual report, physical processes. Unpublished report prepared on behalf of Halpern Glick Maunsell.

Fabricius, K.E., 2005. Effects of terrestrial run-off on the ecology of corals and coral reefs: review and synthesis. Marine Pollution Bulletin, Vol. 50: 125-146.

GHD, 2000. Cocos (Keeling) Islands proposed freight and passenger facilities at Rumah Baru: Notice of Intend, for the Department of Transport and Regional Services, Canberra.

GHD, 2008a. Rumah Baru-Freight and Passenger Facilities, Cocos (Keeling) Islands. Environmental management Plan. Unpublished report prepared on behalf of Attorney-General’s Department, November 2008.

GHD, 2008b. Specification for Rumah Baru, Cocos (Keeling) Islands Freight and Passenger Facilities. Unpublished report prepared on behalf of Attorney-General's Department, December 2008.

Gilmour, J.P., Cooper, T.F., Fabricius, K.E. and Smith, L.D., 2005. Early warning indicators of change in the conditions of corals and coral communities in response to key anthropogenic stressors in the Pilbara, Western Australia. Report prepared by the Australian Institute of Marine Science.

Greenacre, G., Fraser, R. and Seman, P., 2002. Cocos (Keeling) Islands lagoon shipping passage realignment. PIANC 30th International Navigational Congress S2A P12.

Kench, P., 1994. Shoreline stability and environmental impacts of a proposed channel and landing ramp development: Rumah Baru, Cocos (Keeling) Islands. Unpublished report prepared on behalf of Unisearch Limited for Australian Construction Services.

Koskela, R.W., Ringeltaube, P., Small, A., Koskela, T.V., Fraser, A.F., Lee, J.D. and Marshall, P., 2002. Using predictive monitoring to mitigate construction impacts in sensitive marine environments. Recent Advances in Marine Science and Technology.

Maunsell, 2003. Environmental Investigations for the proposed freight and passenger facilities at Rumah Baru. Report to GHD. November 2003

Morton, E., 2007. Marine fauna and dredging. Slide show for Port of Brisbane.

Neves, E.G., 2000. Histological analysis of reproductive trends of three Porites species from Kāne’ohe Bay, Hawai’i. Pacific Science, Vol. 54, no 2: 195-200.

Oliver, J. and Babcock, R., 1992. Spawning corals: sperm dilution effects and in situ measurements of fertilization. Biological Bulletin, Vol. 183: 409-417.

Prince, J., 2003. A statistical analysis of percentage cover of seagrass and algae at the Cocos (Keeling) Islands from spring 2002 to summer 2003.

Simpson, C.J., 1985. Mass-spawning of scleractinian corals in the Dampier Archipelago and the implications for management of coral reefs in Western Australia. Department of Conservation & Environment, Bulletin 244. Perth, Western Australia.

Simpson, C.J., 1991. Mass spawning of corals on Western Australian reefs and comparisons with the Great Barrier Reef. Journal of the Royal Society of Western Australia 74:85-91.

Simpson, C.J., Cary, J.L. and Masini, R.J, 1993. Destruction of corals and other reef animals by coral spawn slicks on Ningaloo Reef, Western Australia. Coral Reefs, Vol 12, No 3-4.

Stoddart, J. and Gilmour, J., 2005. Patterns of reproduction of in-shore corals of the Dampier Harbour, Western Australia, and comparisons with other reefs. Corals of Dampier Harbour: Their survival and Reproduction during the Dredging Programmes of 2004. Unpublished report to Dampier Port Authority and Pilbara Iron.


Simpson, C.J. and Masini, R.J., 1986. Tide and seawater temperature data from the Ningaloo Reef Tract, Western Australia, and the implications for mass spawning. Department of Conservation and Environment, Perth, Bulletin 253.

Taylor, J.G. and Pearce, A.F., 1991. Ningaloo Reef currents: implications for coral spawn dispersal, zooplankton and whale shark abundance. Journal of the Royal Society of Western Australia, 82:57-65.

US Army Corps of Engineers, 2005. Silt Curtains as a Dredging Project Management Practice. Technical Note ERDC TN –DOER-E21.

Veron, J.E.N., 1994. Hermatypic corals of the Cocos (Keeling) Islands: a summary. Atoll Research Bulletin, Vol. No 409.

Woodroffe, C.D. and Berry, P.F., 2004. Scientific studies in the Cocos (Keeling) Islands: an introduction. Atoll Research Bulletin, Chapter 1, No. 399.

Rumah Baru Freight and Passenger Facilities, Cocos (Keeling ...

Documents

Transcript of Rumah Baru Freight and Passenger Facilities, Cocos (Keeling ...