Appendix B Baseline Marine Ecological Studies · Baseline Marine Ecological Studies 2. Methods 2.1Field Survey Timing & Scale This baseline monitoring information was collected over

61/23317/95769 Cocos (Keeling) Islands Home Island Slipway RedevelopmentEnvironmental Management Plan

Appendix B

Baseline Marine Ecological Studies

Attorney General's Department

CKI Home Island Slipway Redevelopment

Baseline Marine Ecological Studies

March 2010

61/23317/96676 CKI Home Island Slipway RedevelopmentBaseline Marine Ecological Studies

Contents

1. Introduction 1

1.1 Background 1

1.2 Objectives 1

2. Methods 3

2.1 Field Survey Timing & Scale 3

2.2 Habitat Mapping & Benthic Community Composition 5

2.3 Sediment Sampling 10

2.4 Water Quality Sampling 12

2.5 Marine Turtles & Other Organisms 14

3. Findings 15

3.1 Greater Study Area – Habitat Mapping 15

3.2 Home Island Slipway – Project Area 19

3.3 Sediment Quality 25

3.4 Water Quality 29

3.5 Marine Mammals 33

3.6 Marine Turtles 33

3.7 Fish 36

3.8 Other Organisms 38

4. Potential Impact Assessment 39

4.1 Project Area – Direct Impacts 39

4.2 Study Area – Indirect Impacts 41

4.3 Offsets & Mitigation 44

5. References 46


Table IndexTable 1 Approximate area estimates (Ha and % of Study

Area) of benthic primary producers within the StudyArea 15

Table 2 Mean percentage coral cover (±SE) observedacross the Study Area 22

Table 3 Mean percentage coral cover (±SE) observedacross the Study Area 24

Table 4 Sediment size classification based on particle sizefrom samples collected across the Study Area 26

Table 5 Water quality summary data summary from theINFINITY-CLW deployed at Site 1 31

Table 6 List of reef fish observed within the Project Area 36Table 7 Light attenuation and predicted surface irradiance

at depth across each of the x5 Monitoring Sitesbased on in-situ measures and the Beer-LambertLaw 42

Figure IndexFigure 1 Location Map & Study Area 2Figure 2 Potential Zones of Influence 4Figure 3 Benthic habitat ground-truthing locations 6Figure 4 Monitoring and benthic assessment locations 7Figure 5 Transect locations in Project Area 9Figure 6 Sediment sampling locations 11Figure 7 Water quality ‘grab’ sampling locations 13Figure 8 Habitat map – Study Area 17Figure 9 Benthic community composition across 15 locations

of the Study Area 18Figure 10 Habitat map – Project Area 23Figure 11 Size frequency distribution of suspended particles

across the Study Area 30Figure 12 Percentage exceedance plot of light irradiance

(µEm-2s-1) at the home island slipway (surface) andfive Monitoring Sites 31

Figure 13 (A) Temperature (°C), (B) Turbidity (FTU) and (C)Chlorophyll- (µg l-1) as recorded at Site 1 from 3December to 6 December, 2009 32

Figure 14 Marine turtle sightings 35Figure 15 Predicted zones of potential impact 40


Figure 16 Predicted surface irradiance at depth across eachof the x5 Monitoring Sites are utilised to definethree Zones of Influence: Zone 1 (Green) – Area ofNo Detectable Effect; Zone 2 (Yellow) Area ofPotential Effect; and Zone 3 (Orange) Zone ofPotential Impact 43

Plate IndexPlate 1 (A) Marine scientists placing (B) transects for

benthic percent cover analysis 5Plate 2 Sediment core sampling performed by a marine

scientist on SCUBA (B) Cores comprised ofunconsolidated surface materials from <30cmsediment depth 10

Plate 3 The (A) Odyssey and INFINITY-CLW data logginginstruments deployed at Site 1 and (B) HydrolabQuanta multi-parameter sonde utilised across theStudy Area 12

Plate 4 Various habitat types observed within the greaterHome Island Study Area 16

Plate 5 Benthic Primary Producer Habitat (BPPH) locatedwithin the waters of the Study Area included (A)hard corals, (B) coraline algae, (C) macro algaeand (D) cyanobacteria 19

Plate 6 Photographs providing a general overview of coralslocated within the Project Area 20

Plate 7 Hard coral species identified within the Project Areainclude (A) Acropora formosa (B) Acropora pulchra,(C) Montipora digitata (D) Porites cylindrica, (E)Pocillopora damicornis, (F),Favia spp., (G) Poriteslobata, and (H) Fungia fungates 21

Plate 8 Alga of the Project Area included those from thegenus (A) Caulerpa, (B) Padina, (C) Halimedia, and(D) Polysiphonia 24

Plate 9 Green turtles (Chelonia mydas) observed (A)actively swimming within the Study Area and (B) atrest near location 12 33

Plate 10 Coastline photos from (A & B) Direction Island (C)Prison Island and (D) Home Island, north of theHome Island wharf 34

Plate 11 Sample photos of reef fish observed within theProject Area including (A & B) Pomacentridae (C)


Lutjanids (D) Nemipterids and Acanthuridae (E & F)Apogonids (G) Chaetodontids (F) Tripterygiids 37

Plate 12 Other organisms observed within waters of theProject Area (A) sponges, (B) hydroids, (C) seasquirts, (D) gastropods, (E) sea urchins and (F)crustaceans (C & D) clams 38

Plate 13 Individual coral heads (bommies) located along thenorth-west rock wall 45

Plate 14 Photographs of old equipment which is now debriswithin the Project Area including (A) rope, (B)anchors, and (C) tyres 45

AppendicesA Monitoring Site & Sampling Location CoordinatesB Benthic Cover across the Study AreaC Reported Analyte Concentrations in Marine Sediment SamplesD Particle Size Distribution of Marine Sediment Samples – Analytical

ReportsE Reported Analyte concentrations in Marine Water samplesF Particle Size Analysis of Marine Water Samples – Analytical

Report


1. Introduction

1.1 BackgroundThe Attorney-General’s Department (the Department), is proposing to redevelop the existing slipwayfacility on the western coast of Home Island, of the Cocos (Keeling) Islands, Australian Indian OceanTerritories (Figure 1). Works associated with the redevelopment of these facilities include the removal ofone of the existing slipways, the construction of a new slipway capable to accommodate theDepartment’s new and existing vessels, further reclamation of a nearby shoreline, as well as dredgingworks adjacent to the Home Island wharf and in the harbour approach channel (the “Project”).

Currently the design of the new slipway is in development by GHD Pty Ltd (GHD) and the Project is beingreferred to the Department of the Environment, Water, Heritage and the Arts (DEWHA) for environmentalapproval. As part of this process, the Department has commissioned the GHD Ecology and MarineSciences team to undertake baseline marine ecological studies in effort to locate sensitive receptors withinand adjacent to the Project area, identify opportunities for impact avoidance and minimisation, andquantify the areas of potentially adverse effects resulting from the proposed redevelopment.

The focus of these investigations was to determine the presence of ecological communities that may beremoved or disturbed from the proposed construction works. Of particular interest are the BenthicPrimary Producers (BPPs) and their respective habitats. These include marine plants (e.g. seagrasses,mangroves, algae), but also include invertebrates such as scleractinian (hard) corals. These organismsgrow attached to the seabed and are considered an integral part in the maintenance of ecosystemintegrity in terms of species composition, diversity and function.

In addition to BPPs, the presence of marine mammals, marine turtles, fish and other organisms werealso recorded.

Marine sediments and water samples were also collected within, and outside of, the proposed dredgearea in effort to detect the presence of metals, tributyltin (TBT), and/or hydrocarbon contaminants thatmay be disturbed during construction. Sediment particle size distribution frequency (PSD), an importantparameter that could be influenced through dredging and construction activity, was included in theanalysis as changes in this parameter may affect local water quality, sediment transport and relevantecological communities.

This report summarises observations of the general marine communities within the greater Project areaand results of the initial monitoring of the sediment chemistry and water quality during these baselineinvestigations.

1.2 ObjectivesThe objectives of this ecological assessment were to:1. Locate, identify and delineate sensitive marine receptors, in particular BPPs and their habitats,

located within and adjacent to the footprint of the proposed Project that may be directly removed oradversely affected from construction works and/or indirectly affected through the mobilisation ofsuspended sediment plumes generated from these activities; and

2. Produce a report suitable for submission to the regulatory authorities that would facilitate the ability offuture studies to detect and document changes from the baseline habitat condition.

DIRECTION ISLAND

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Horizontal Datum: World Geodetic System 1984Grid: Universal Transverse Mercator, Zone 47S o

© 2010. While GHD has taken care to ensure the accuracy of this product, GHD and AGD make no representations or warranties about its accuracy, completeness or suitability for any particular purpose. GHD and AGD cannot accept liability of any kind (whether in contract, tort or otherwise) forany expenses, losses, damages and/or costs (including indirect or consequential damage) which are or may be incurred as a result of the product being inaccurate, incomplete or unsuitable in any way and for any reason.

Attorney General's DepartmentCKI Home Island Slipway EPBC Referral (CKI Port)

Figure 1

Job NumberRevision 0

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Location Map & Study Area

Date

Data Source: AGD: Cocos Island Imagery 2003; GHD: Study Area 20100304. Created by: nnikmohdkamil, xntan

GHD House, 239 Adelaide Terrace Perth WA 6004 T 61 8 6222 8222 F 61 8 6222 8555 E [email protected] W www.ghd.com.au

1:50,000 (at A3)

Study Area

WESTERNAUSTRALIAINDIAN OCEAN

COCOS (KEELINGS)ISLAND

Locality Map

AttorneyGeneral'sDepartment


2. Methods

2.1 Field Survey Timing & ScaleThis baseline monitoring information was collected over two field surveys. The first field survey wasperformed in the ‘doldrum’ season during the week of 23 March to 27 March, 2009 while the secondsurvey was undertaken during the ‘trade wind’ season from 2 December to 7 December, 2009.

The first assessment focused primarily on the Home Island Slipway region within and adjacent to thepotential dredge footprint, hereafter referred to as the ‘Project Area’. The Project Area was re-assessedduring the second field survey, but also included investigations on a larger scale to improveunderstanding of those areas within and adjacent to the possible ‘Zone of Influence’ of a dredge plumeas predicted by numerical modelling (Figure 2, GHD, 2010). This larger area is referred to hereafter asthe ‘Study Area’.

Assessing these areas at different times of the year was considered beneficial for this baseline studyprogram because meteorological and oceanographic seasonal variability allows for the possibility toobserve local ecological and water/sediment quality responses.

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Map Projection: Transverse MercatorHorizontal Datum: World Geodetic System 1984Grid: Universal Transverse Mercator, Zone 47S o



Figure 2


612331706

16 MAR 2010

Potential Zones of Infidence

Date

Data Source: AGD: Cocos Island Imagery 2003; GHD: Dredge Footprint 201003, Study Area 20100304, Plume Modelling Results 201003. Created by: Nik Fadhil, nnikmohdkamil, xntan


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Dredge Footprint

Plume (mg/L)1 to 3

3 to 5

>5


2.2 Habitat Mapping & Benthic Community Composition

2.2.1 Greater Study Area – Habitat Mapping

Efficient assessment of the benthic composition across the Study Area required a combination of initialdelineation from rectified aerial imagery followed by rapid visual assessment at multiple locations in situ,also known as ‘ground-truthing’.

It was not possible to define benthic community types from the aerial images alone although a roughdelineation was developed (i.e. presence/absence) for use in the field. This aerial imagery and initialdelineation was uploaded into Trimble Nomad 800L handheld GPS (Trimble Navigation Ltd, SunnyvaleCalifornia, USA) that was pre-loaded with ArcPad v 7.1 (ESRI Inc, Redlands California, USA).

Working aboard the “Sekali Goose”, a 7m semi-inflatable glass-bottom boat, the survey team (comprisedof two marine scientists) was able to clearly view the benthic substrate whilst travelling throughout theStudy Area and recording the position and type of cover at over 800 ground-truthing points during theDecember survey. The locations of these points are illustrated in Figure 3. This data was downloaded,plotted and interrogated using ArcGIS v 9.2 software (ESRI Inc, Redlands California, USA).

2.2.2 Greater Study Area – Benthic Composition

To obtain a better understanding of the benthic composition of the Study Area a percent coverassessment was also performed involving fifteen locations across the area (Figure 4). At each site,x2 (25m) transects were positioned by experienced marine scientists on SCUBA end to end,perpendicular to each other (i.e. forming an “L” shape) along the substrate (Plate 1). Digital video wasthen captured by divers swimming approximately 50cm above each tape using an Olympus µTOUGH-8000 (x12.0 MP) digital camera.

This video was decompiled using Blaze Media Pro v 9.10 software (Mystik Media, Hampstead NorthCarolina, USA) with x25 still images randomly selected from each transect for percent cover analysisusing Coral Point Count with Excel extensions (CPCe) software package developed by the US NationalCoral Reef Institute, Daina Beach, Florida (Kohler and Gill, 2006). Specifically, each image wasinterrogated with x25 points distributed in a stratified random design and basic statistical interrogationperformed using Microsoft Excel (2007).

(A) (B)

Plate 1 (A) Marine scientists placing (B) transects for benthic percent cover analysis

DIRECTION ISLAND

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Benthic HabitatFigure 3


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Ground Truthing Locations

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Data Source: AGD: Cocos Island Imagery 2003; GHD: Benthic Habitat Ground Truthing Locations 20091207, Study Area 20100304. Created by: Nik Fadhil, nnikmohdkamil, xntan


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Monitoring and BenthicFigure 4


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Assessment Locations

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Data Source: AGD: Cocos Island Imagery 2003; GHD: Benthos Assessment and Monitoring Sites 200912, Study Area 20100304. Created by: nnikmohdkamil, xntan


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2.2.3 Home Island Slipway – Project Area

Assessment of BPP habitat within the Project Area was performed by a marine scientist working from theshoreline and aboard the Sekali Goose. Working to a depth of approximately -3m on Snorkel, x25 (50m)transects were positioned along the benthos with a handheld Garmin GPS-76 accurate to ±5m. Themajority of transects were run north of the existing wharf as this is the area that would be directly affectedby the proposed dredging. However, to improve understanding of the area and the potential forsecondary effects of construction, transects were also laid to the south (x4) and west (x2) of the slipwayand (x2) along a submerged rock breakwater located to the north-west. The position of these transectsare illustrated in Figure 5.

Still photographic images were captured approximately every 3m along each transect with an OlympusµTOUGH-8000 (x12.0 MP) digital camera. Each of these images was quantitatively assessed forpercentage cover with CPCe software and interrogated with x25 points distributed in a stratified randomdesign. Basic statistical interrogation was performed with Microsoft Excel (2007).

The distribution of marine benthic communities were qualitatively delineated by aerial photography andground-truthed during transect deployment and various random swims within the Project Area.

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Figure 5


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Transect Locations in Project Area

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Data Source: AGD: Cocos Island Imagery 2003; GHD: Markers, Transects and Moorings 20090401, Ground Truthing Locations 20091207, Dredge Footprint 201003, Rock Wall 201003. Created by: nnikmohdkamil, xntan


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Documents

Appendix B Baseline Marine Ecological Studies · Baseline Marine Ecological Studies 2. Methods 2.1Field Survey Timing & Scale This baseline monitoring information was collected over