Maintenance Dredging 2015 Environmental Monitoring · PDF fileBMT Oceanica: Southern Ports Authority: Maintenance Dredging 2015 Environmental Monitoring Report iii Acronyms APA Albany

Maintenance Dredging 2015 Environmental

Monitoring Report

1208_001/1_Rev0 July 2015

P:\SouthernPorts\1208_PortAlbanyMaintDredging\001_OriginalScope\Reports\ReportFolder_EnvironmentalMonitoring\AlbanyPorts2015MaintDredging_EnvMon_1208_Rev0_20150729.docm

Maintenance Dredging 2015 Environmental Monitoring Report

Prepared for

Southern Ports Authority

Prepared by

BMT Oceanica Pty Ltd

July 2015

Report No. 1208_001/1_Rev0

Client: Southern Ports Authority

Document history

Distribution

Revision Author Recipients Organisation No. copies

& format Date

A J. Anderson L. Twomey BMT Oceanica 1 x docm 21/07/2015

B J. Anderson L. Twomey BMT Oceanica 1 x docm 22/07/2015

C J. Anderson R. Hillman BMT Oceanica 1 x docm 23/07/2015

D J. Anderson R. Goetze Southern Ports Authority 1 x pdf 23/07/2015

0 J. Anderson R. Goetze Southern Ports Authority 1 x pdf 29/07/2015

Review

Revision Reviewer Intent Date

A L. Twomey Technical review 21/07/2015

B L. Twomey Editorial review 22/07/2015

C R. Hillman Administrative review 23/07/2015

D R. Goetze Client review 24/07/2015

Quality Assurance

BMT Oceanica Pty Ltd has prepared this report in accordance with our Health Safety Environment

Quality Management System, certified to ISO 9001: 2008.

Status

This report is 'Draft' until approved for final release, as indicated below by inclusion of signatures from: (i) the author

and (ii) a Director of BMT Oceanica Pty Ltd or their authorised delegate. A Draft report may be issued for review with

intent to generate a 'Final' version, but must not be used for any other purpose.

Approved for final release:

Author Director (or delegate) Date: 29/07/15 Date: 29/07/15

Disclaimer

This report has been prepared on behalf of and for the exclusive use of Southern Ports Authority, and is subject to and

issued in accordance with the agreed terms and scope between Southern Ports Authority and BMT Oceanica Pty Ltd.

BMT Oceanica Pty Ltd accepts no liability or responsibility for it in respect of any use of or reliance upon this report by

any third party.

Copying this report without prior written consent of Southern Ports Authority or BMT Oceanica Pty Ltd is not permitted.

© Copyright 2015 BMT Oceanica Pty Ltd

BMT Oceanica: Southern Ports Authority: Maintenance Dredging 2015 Environmental Monitoring Report i

Contents

Acronyms ................................................................................................................................... iii

Executive Summary ................................................................................................................... v

1. Introduction ....................................................................................................................... 1

1.1 Environmental approvals ...................................................................................... 1

1.2 Potential environmental impacts .......................................................................... 3

1.3 Purpose of document ............................................................................................ 3

1.4 Objectives .............................................................................................................. 3

2. Methods ............................................................................................................................. 4

2.1 Turbidity plumes .................................................................................................... 4

2.1.1 Secchi disc monitoring .................................................................................. 4

2.1.2 Visual record of turbidity plumes ................................................................... 4

2.1.3 Seagrass epiphyte monitoring ...................................................................... 4

2.2 Marine fauna ........................................................................................................... 5

2.2.1 Trained observers ......................................................................................... 5

2.3 Introduced marine species .................................................................................... 5

3. Results ............................................................................................................................... 7

3.1 Turbidity monitoring .............................................................................................. 7

3.1.1 Remote imagery units ................................................................................... 8

3.1.2 Seagrass epiphyte monitoring ...................................................................... 8

3.1.3 Marine fauna ................................................................................................ 8

4. Summary and discussion ............................................................................................... 10

5. References ....................................................................................................................... 11

ii BMT Oceanica: Southern Ports Authority: Maintenance Dredging 2015 Environmental Monitoring Report

List of Figures

Figure 1.1 Albany Port harbour basin, entrance channel and disposal area ........................... 2

Figure 2.1 Turbidity and seagrass monitoring sites for the 2015 maintenance dredging

campaign .............................................................................................................. 6

List of Tables

Table 2.1 Secchi disc depth and seagrass epiphyte loading monitoring sites ....................... 5

Table 3.1 Dates of completed environmental monitoring during dredging campaign ............. 7

Table 3.2 Water clarity monitoring (secchi disc depth) as part of the 2015 maintenance

dredging campaign ................................................................................................ 7

Table 3.3 Seagrass epiphyte loading monitoring as part of the 2015 maintenance

dredging campaign ................................................................................................ 8

Table 3.4 Observations of marine mammals during dredging operations .............................. 9

List of Appendices

Appendix A Remote imagery photo examples

Appendix B Seagrass epiphyte loading photo examples

Appendix C Marine mammal observation logs

BMT Oceanica: Southern Ports Authority: Maintenance Dredging 2015 Environmental Monitoring Report iii

Acronyms

APA Albany Port Authority, now part of SPA

AQIS Australian Quarantine Inspection Service

CS Control Site

DoE Commonwealth Department of the Environment

DoF Western Australian Department of Fisheries

DoW Western Australian Department of Water

EIA Environmental impact assessment

EPA Environmental Protection Authority

EPBC Environment Protection and Biodiversity Conservation

IMS Introduced Marine Species

IS Inner Site

LoR Limit of reporting

MMO Marine mammal observer

OEPA Western Australian Office of the Environmental Protection Authority

OS Outer Site

QA/QC Quality assurance and quality control

SAP Sampling and Analysis Plan

SPA Southern Ports Authority

WA Western Australia

BMT Oceanica: Southern Ports Authority: Maintenance Dredging 2015 Environmental Monitoring Report v

Executive Summary

Southern Ports Authority commissioned maintenance dredging within the Port of Albany in

June 2015 to remove high spots in the entrance channel and harbour basin to reinstate the

declared navigation depths.

BMT Oceanica undertook environmental monitoring during the maintenance dredging program to

fulfil the environmental commitments made by the Southern Ports Authority.

The monitoring program included the following components:

1. Monitoring of the dredging turbidity plumes through:

i. Measuring water clarity with a Secchi disc

ii. Capturing a visual record of turbidity plumes within the harbour basin to record the

distribution of plume movement over time to assist with planning for future dredging

campaigns

iii. Visually assessing any change on epiphyte loading in seagrass meadows.

2. Mitigation of potential vessel impact with whales and other protected marine fauna by

completing marine mammal observer training of the maintenance dredging vessels crew for

cetacean impact avoidance measures

3. Reducing the potential for introduced marine species from dredging operations by consulting

with Western Australian Department of Fisheries (DoF) on appropriate steps to risk assess

potential pest vectors

4. Reporting on Secchi disc depth (i.e. water clarity) and seagrass epiphyte loading monitoring

results (this report).

All of the environmental commitments outlined in the EIA (BMT Oceanica 2014) were satisfied by

the Albany Port 2015 maintenance dredging environmental monitoring, which included:

There were no exceedances of turbidity. Monitoring of water clarity through secchi disc depth

measurements found short lived decreases in water clarity and these were limited to harbour

and near the harbour entrance sites (IS1-4 and OS1).

Minor differences occurred in seagrass epiphyte loading at sites CS1 (decreased) and OS7

and OS8 (increased), while sites OS5 and OS6 had no change.

Three remote imagery units were deployed for a period of up to 28 days, which resulted in

collection of over 3,000 photos of the maintenance dredging operation. The information may

be useful to inform decision making for future dredging campaigns.

The potential impacts to marine fauna from vessels were managed through comprehensive

marine mammal observation training. A total of 53 Humpback whale adults and nine calves

were observed by the dredge vessel crew during the dredging operations. Approximately

seven hours of shutdown time was required for impact avoidance procedures, but no impacts

to marine mammal were recorded.

The risk of IMS incursion was determined to be low by Department of Fisheries due to the

recent dry docking of the dredge vessel and associated support vessels.

BMT Oceanica: Southern Ports Authority: Maintenance Dredging 2015 Environmental Monitoring Report 1

1. Introduction

The Port of Albany is located on the southern coast of Western Australia with infrastructure in

Princess Royal Harbour and King George Sound (Figure 1.1). Southern Ports Authority (SPA)

was required to undertake maintenance dredging to remove high spots within the Port of Albany

entrance channel and harbour basin, to reinstate the declared navigation depths.

Dredging commenced on 31 May at 1400 and works were completed on 15 June 2015.

Additional sweep bar works continued until 19 June 2015. Dredging works were completed with

a Trailer Suction Hopper Dredge, the River Bee, operated by WA Dredging. Southern Ports

Authority was authorised to dispose of 82,400 m3 of dredged material to an offshore disposal

area (G7 Figure 1.1), in accordance with sea dumping permit SD2014/2902. The total volume

dredged during the campaign was calculated to be 52,482 m3, which was significantly less than

the amount approved.

1.1 Environmental approvals

Environmental approvals for the 2015 maintenance dredging works consisted of:

EPBC referral

Licence to Dredge and Reclaim

Sea Dumping permit

The maintenance dredging works were not considered to be a controlled action and EPBC

approval was provided by Department of Environment (DoE) on 17 July 2014 (EPBC 2014/7246).

An application for a Licence to Dredge and Reclaim was submitted to Western Australia (WA)

Department of Water on 17 June 2014. The works were directly referred to the OEPA and the

outcome was ‘Not Assessed – Public Advice Given (Dated 8 Sept 2014). The Western Australia

Department of Water issued a Licence to Dredge and Reclaim on 14 November 2015.

Sea Dumping permit (No. SD2014/2902) was granted by DoE on 2 December 2014 for up to

82,400 m3 of dredging materials for disposed at site (G7) in King George Sound (Figure 1.1).

Potential environmental impacts were assessed in the Albany Port Authority Maintenance

Dredging Program Environmental Impacts Assessment (EIA) report (BMT Oceanica 2014a).

These potential impacts were assessed based on data presented in the Albany Port Authority

Maintenance Dredging Program Sediment Sampling and Analysis Implementation report

(BMT Oceanica 2014b).

2 BMT Oceanica: Southern Ports Authority: Maintenance Dredging 2015 Environmental Monitoring Report

Figure 1.1 Albany Port harbour basin, entrance channel and disposal area


1.2 Potential environmental impacts

A number of key potential impacts for the 2015 maintenance dredging campaign were identified

in the EIA which included:

turbidity

mobilisation of contaminants and nutrients

hydrocarbon spills

noise

vessel movements

threatened or migratory species

introduced marine species

waste management

impacts to other users

exposure to contaminants.

The potential impacts were risk assessed and management actions were developed to mitigate

the risks. The risk assessment identified three environmental issues for monitoring during the

dredging campaign, including:

turbidity

migratory species (marine mammals)

introduced marine species.

1.3 Purpose of document

This document presents the results of the environmental monitoring requirements of the Albany

Port Authority Maintenance Dredging Program Environmental Impacts Assessment report.

1.4 Objectives

Requirements of the Albany Port Authority Maintenance Dredging Program Environmental

Impacts Assessment (BMT Oceanica 2014a) were:

1. Monitoring of the dredging turbidity plumes through:

i. Measuring water clarity with a secchi disc

ii. Capturing a visual record of turbidity plumes within the harbour basin to record the

distribution of plume movement over time to assist with planning for future dredging

campaigns

iii. Visually assessing any change on epiphyte loading in seagrass meadows.

2. Mitigating potential of vessel to impact with whales and other protected marine fauna by

completing marine mammal observer training for vessel crew for cetacean impact avoidance

measures

3. Reducing the potential for introduced marine species from dredging operations by consulting

with Western Australian Department of Fisheries (DoF) on appropriate steps to risk assess

potential pest vectors

4. Reporting on secchi disc depth (i.e. water clarity) and seagrass epiphyte loading monitoring

results (this report).


2. Methods

2.1 Turbidity plumes

Turbidity of the dredging plumes were monitored with the following methods:

1. Measurement of water clarity with a secchi disc

2. Capture of a visual record of turbidity plumes within the harbour basin using remote imagery

units to record the distribution of plume movement over time to assist with planning for future

dredging campaigns

3. Visual assessment of any change on epiphyte loading in seagrass meadows.

2.1.1 Secchi disc monitoring

Dredging was completed within two weeks and turbidity was monitored in case there was an

unexpected extension of the dredging program. Turbidity was monitored using Secchi depth as a

proxy for water quality (i.e. water clarity) at five ‘inner sites’, eight ‘outer sites’ and one ‘control

site’ (Table 2.1 and Figure 2.1). Monitoring was undertaken by recording the Secchi depth, which

was conducted by lowering the Secchi disc through the water column and estimating the depth

that the white and black quarters of the Secchi disc were still distinguishable. Secchi depths

were monitored pre-dredging and after dredging for contextual information. During dredging a

staged trigger and action approach was employed, as follows:

1. Secchi disc monitoring was carried out twice weekly at all sites during dredging

2. If the Secchi depth at one or more of the outer sites was below 4 m (8 m for sites OS7 and

OS8) while the Secchi depth at site CS1 remained above 4 m, monitoring increase to daily

3. If Secchi depths remained below 4 m (8 m for sites OS7 and OS8) at one or more outer sites

on three consecutive days while site CS1 remained above 4 m then dredging will cease until

Secchi depths were greater than 4 m at all outer sites (8 m for sites OS7 and OS8).

2.1.2 Visual record of turbidity plumes

A visual record of turbidity plumes was recorded within the harbour basin using two remote

imagery units (i.e. time lapse cameras). Harbour camera 1 faced east and collected images of

the entrance channel. Harbour camera 2 faced southwest and collected images of the inner

harbour basin area. An additional time lapse camera was mounted on the stern of the dredge

vessel to collect further information on the turbidity plumes during the campaign. Images were

taken every 15 minutes from sunrise to sunset each day.

2.1.3 Seagrass epiphyte monitoring

Seagrass epiphyte loading was monitored to document any potential effect of nutrient release on

epiphyte growth. Photographs of the seagrass meadows were taken in ten randomly placed

20 x 20 cm quadrats, one week prior to, once during, and one week after dredging at the control

sites and each of the outer sites with seagrass (CS1, OS5, OS6, OS7 and OS8) (Table 2.1 and

Figure 2.1). Epiphyte cover was visually assessed from photographs and qualitatively classified

as low, medium or high density by a local seagrass expert.


Table 2.1 Secchi disc depth and seagrass epiphyte loading monitoring sites

Site Description Type Location (GDA94 UTM 50)

Easting Northing

IS1 Inner Site Secchi disc 581189 6122602





OS1 Outer Site Secchi disc 581322 6122247




OS5 Outer Site Secchi disc

Seagrass epiphyte 583113 6121558







CS1 Control Site Secchi disc


2.2 Marine fauna

Risks to marine fauna from vessel impacts were managed by mitigating potential of vessel to

impact with whales and other protected marine fauna by the vessel crew completing marine

mammal observer training for cetacean impact avoidance measures.

2.2.1 Trained observers

The River Bee vessel crew attended a one day marine mammal observer (MMO) course on

27 May 2015. This course was taught by Rochelle Desmond of BMT Oceanica who has

extensive experience in marine mammal observation work. The course included regulatory and

operational aspects of interactions with marine fauna at sea. Learning aids were provided and

included a training manual and marine fauna field guide. Training also included examples of:

vessel pre-start checklists, observation recording forms, MMO summary sheets, reporting chain,

and auditing procedures.

2.3 Introduced marine species

Risks of marine pest introductions were managed by reducing the potential for introduced marine

species (IMS), from dredging operations; by consulting with DoF on appropriate steps to risk

assess potential pest vectors. Due to the recent dry dock history (May 2015) of the River Bee, an

IMS low risk approval application was submitted to the Marine Biosecurity branch of DoF on

20 May 2015. Further to this, additional IMS low risk approval applications were submitted for the

dredging support vessels (Flinders Bay, Total Assist and Total Response) on 25 May 2015. DoF

approved the designation of low risk for the vessels on 27 May 2015 and no further actions were

required for IMS relating to the vessels hulls.


Figure 2.1 Turbidity and seagrass monitoring sites for the 2015 maintenance dredging

campaign


3. Results

Field survey monitoring of secchi depths and seagrass epiphytes was completed by Bastyan &

Associates. Survey dates for each secchi depth and seagrass epiphyte monitoring event are

listed in Table 3.1.

Table 3.1 Dates of completed environmental monitoring during dredging campaign

Date Campaign stage Monitoring action Sites

25 May 2015 Pre-dredging Secchi disc All

Seagrass epiphytes CS1, OS5, OS6, OS7 and OS8

4 June 2015 Week 1 dredging Secchi disc All


8 June 2015 Week 1 dredging Seagrass epiphytes CS1, OS5, OS6, OS7 and OS8



24 June 2015 Post dredging Secchi disc All

Seagrass epiphytes CS1, OS5, OS6, OS7 and OS8

Remote imagery units were installed on port infrastructure within the inner harbour and on the

dredge vessel on 27 May 2015. Units were removed from the dredge vessel on 22 June and

from the harbour infrastructure on 25 June 2015.

3.1 Turbidity monitoring

Water clarity was monitored once prior to dredging, four times during dredging and once after

dredging as part of the environmental monitoring of the dredging campaign (Table 3.2). No

additional monitoring was required as minimal visual depth triggers were never reached or

exceeded. Site OS2 was recorded as >3.9 m on 4 June, but this measurement represented the

secchi disc on the seabed and thus visibility had not been reduced.

Table 3.2 Water clarity monitoring (secchi disc depth) as part of the 2015 maintenance

dredging campaign

Site Description

Minimum

depth

trigger (m)

Secchi disc depth (m)

25 May 4 June 7 June 10 June 12 June 24 June

IS1 Inner Site 4 >11.8 9.0 4.7 7.9 10.0 5.5

IS2 Inner Site 4 >10.5 >10 4.5 7.5 10.0 9.5

IS3 Inner Site 4 >10.8 9.5 9.5 7.0 9.1 9.7

IS4 Inner Site 4 >11.5 10.0 10.5 7.2 9.8 9.2

IS5 Inner Site 4 >11.2 9.8 >10.8 >11.0 >11.3 >11.0

OS1 Outer Site 4 >7.3 >7.5 4.5 6.5 >7.5 >7.5

OS2 Outer Site 4 >4.0 >3.9 >4.1 >4.1 >4.2 >4.1

OS3 Outer Site 4 >6.0 >5.7 >5.6 >6.0 >6.3 >5.7

OS4 Outer Site 4 >6.2 >6.0 >6.0 >5.8 >6.4 >5.8

OS5 Outer Site 4 >5.6 >5.4 >5.4 >5.4 >5.9 >5.8

OS6 Outer Site 4 >6.2 >5.6 >5.6 >5.6 >6.4 >6.1

OS7 Outer Site 8 >12.4 >12.2 >12.4 >12.5 >12.8 >12.1

OS8 Outer Site 8 >13.0 >13.2 >13.0 >12.6 >13.2 12.3

CS1 Control Site >4 >4.2 4.1 4.0 4.5 4.7 4.5

Note:

1. Data with > indicates secchi disc was visible on seabed


3.1.1 Remote imagery units

The remote imagery units captured more than 3,000 photos throughout the dredging campaign.

Although photo quality varied due to weather conditions, refraction from sea surface and

limitations of available light, hundreds of photos were collected. The photos have provided

valuable information on plume distribution and dispersion within the harbour basin, which may be

useful to inform decisions for future dredging campaigns. The images revealed surface plumes

of sediments with proximity to dredging and disposal. In general, the photos revealed relatively

small turbidity plumes which were short lived, particularly in the entrance channel. The harbour

turbidity plumes were a darker colour and appeared to remain slightly longer. Example photos

are found in (Appendix A).

3.1.2 Seagrass epiphyte monitoring

Seagrass epiphyte monitoring was completed three times as part of the dredging campaign

(Table 3.3). Some slight differences in seagrass epiphyte loading were noted amongst surveys.

Representative photos of sites during each survey are provided in Appendix B. Changes include

a decrease of epiphytes at the control site during the post dredging survey, and a slight increase

in epiphytes at OS7 and OS8. No noticeable change occurred at sites OS5 and OS6.

Table 3.3 Seagrass epiphyte loading monitoring as part of the 2015 maintenance

dredging campaign

Site Description Depth (m) Seagrass epiphyte loading (density)

25 May 8 June 24 June

CS1 Control Site 4.0 High High Medium

OS5 Outer Site 5.5 Low Low Low

OS6 Outer Site 6.0 Low Low Low

OS7 Outer Site 12.5 Low Low Medium

OS8 Outer Site 12.5 Low Low Medium

3.1.3 Marine fauna

Marine mammal observations were completed by the River Bee vessel crew during hours of

dredging operations (see Appendix C for logs). Marine mammal observers continually monitored

for marine mammals during dredging operations and marine mammal sightings were recorded on

an hourly basis. Additionally, a minimum of five minutes of visual observation for marine

mammals was completed prior to operations daily start up and a 20 minute observation period

(with the aid of binoculars) prior to the commencement of dumping activities. A total of 53

Humpback whale adults, nine Humpback calves and two seals were observed by the vessel crew

during dredging operations (Table 3.4). Although most marine mammals were not within the

300 m operations exclusion zone, approximately seven hours of shut down time was required

during the campaign as part of the cetacean impact avoidance stop work and continuation

procedures.


Table 3.4 Observations of marine mammals during dredging operations

Date Humpback whale adult Humpback whale calves Other mammal Required shutdown

time (hr)

31 May 2015 - - - 0

1 June 2015 - - - 0

2 June 2015 - - - 0

3 June 2015 - - 2 seals 0

4 June 2015 5 - - 1

5 June 2015 - - - 0

6 June 2015 - - - 0

7 June 2015 - - - 0

8 June 2015 - - - 0

9 June 2015 - - - 0

10 June 2015 28 5 - 6

11 June 2015 14 2 - 0

12 June 2015 - - - 0

13 June 2015 2 1 - 0

14 June 2015 4 1 - 0

15 June 2015 - - - 0

Total 53 9 2 7


4. Summary and discussion

All of the environmental commitments outlined in the EIA (BMT Oceanica 2014) were satisfied by

the Albany Port 2015 maintenance dredging environmental monitoring. The key results included:

There were no exceedances of turbidity. Monitoring of water clarity through secchi disc depth

measurements and seagrass epiphyte loading resulted in no exceedances. Secchi disc

depth measurements found short lived decreases in water clarity and these were limited to

the harbour and near the harbour entrance sites (IS1-4 and OS1). Slight differences occurred

in seagrass epiphyte loading at sites CS1 (decreased) and OS7 and OS8 (increased) but no

change was noted at sites OS5 and OS6.

Three remote imagery units were deployed for a period of up to 28 days, which resulted in

collection of over 3,000 photos of the maintenance dredging operation. The information may

be useful to inform decision making for future dredging campaigns.

The risk of IMS incursion was determined to be low by Department of Fisheries due to the

recent dry docking of the dredge vessel and associated support vessels.

The potential impacts to marine fauna from vessels were managed through comprehensive

marine mammal observation training supplied by BMT Oceanica. A total of 53 Humpback

whale adults and nine calves were observed during the dredging operations. Approximately

seven hours of shutdown time was required due to impact avoidance procedures, but no

impacts to marine mammals were recorded.


5. References

BMT Oceanica (2014a) Albany Port Authority Maintenance Dredging Program: Environmental

Impact Assessment. Prepared for Albany Port Authority by BMT Oceanica Pty Ltd, Report

No. 812_01_002/2_Rev1, Perth, Western Australia, August 2014

BMT Oceanica (2014b) Albany Port Authority Maintenance Dredging Program – Sediment

Sampling and Analysis Implementation. Prepared for Albany Port Authority by BMT

Oceanica Pty Ltd, Report No. 812_01_002/1_Rev0, Perth, Western Australia, May 2014

Appendix A

Remote imagery photo examples

Appendix B

Seagrass epiphyte loading photo examples

Appendix C

Marine mammal observation logs

BMT Oceanica Pty Ltd

PO Box 462 Wembley

WA 6913 Australia

Tel: +61 8 6272 0000

Fax: +61 8 6272 0099

[email protected]

www.bmtoceanica.com.au

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Maintenance Dredging 2015 Environmental Monitoring · PDF fileBMT Oceanica: Southern Ports Authority: Maintenance Dredging 2015 Environmental Monitoring Report iii Acronyms APA Albany