Bimonthly Seagrass Monitoring Report - Dredging Report 2

Transcription

1 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Ichthys Nearshore Environmental Monitoring Program L384-AW-REP Prepared for INPEX February 2013

2 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Document Information Prepared for INPEX Project Name File Reference L384-AW-REP-10048_0_Bimonthly Seagrass Monitoring Dredging Report 2.docm Job Reference L384-AW-REP Date February 2013 Document Control Version Date Author Author Initials Reviewer Reviewer Initials A 1/02/2013 Isabel Jimenez IJ Craig Blount CB Andrea Nicastro Brendan Alderson AN BA B 08/02/2013 Brendan Alderson BA Craig Blount CB C 13/02/2013 Brendan Alderson BA Craig Blount CB 0 15/02/2013 Brendan Alderson BA Craig Blount CB Cardno (NSW/ACT) Pty Ltd Cardno WA Pty Ltd Cardno NT Pty Ltd Level 9, The Forum 11 Harvest Terrace Level 6, 93 Mitchell St 203 Pacific Highway West Perth WA 6005 Darwin NT 0800 St Leonards NSW 2065 Telephone: Telephone: Telephone: Facsimile: Facsimile: Facsimile: This document is produced by Cardno solely for the benefit and use by the client in accordance with the terms of the engagement for the performance of the Services. Cardno does not and shall not assume any responsibility or liability whatsoever to any third party arising out of any use or reliance by any third party on the content of this document. Prepared for INPEX Page ii

3 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Executive Summary A Seagrass Monitoring Program has been developed to detect potential changes in seagrass health indicators and infer whether any changes are a result of dredging and/or spoil disposal activities associated with the Ichthys Project (the Project) in Darwin Harbour. The program involves repeat surveys of permanent monitoring sites to determine trends in the cover and density of seagrasses at potential Impact and Control locations. These datasets are collected in parallel with the Water Quality and Subtidal Sedimentation Monitoring Program, to provide a suite of early warning indicators for assessing the health of seagrasses. This report outlines the findings of the second seagrass drop camera monitoring survey (D2) undertaken since the commencement of dredging (6 to 9 December 2012). The results from Survey D2 show a decrease in seagrass density and percent cover at Impact locations (Lee Point, Fannie Bay and Woods Inlet) since the end of baseline (B3, 27 August 2012), but no change since the previous dredging survey (Survey D1; 6 to 9 November 2012). Mean seagrass leaf density was similar at pooled Impact and Control locations, with 557 ± 34 leaves/m 2 and 556 ± 31 leaves/m 2 (standard error (SE)) respectively. Gross changes in leaf density (i.e. difference between D2 and baseline values) at Impact and Control locations was -1,412 leaves/m 2 and -560 leaves/m 2 respectively. The net change in leaf density relative to baseline and Control locations (i.e. gross change at Impact locations minus gross change at the Control locations) was -852 leaves/m 2. This represents a relative decrease of 43% from average baseline leaf density of 1,969 ± 108 leaves/m 2 and exceeds the Level 3 trigger value of 30% net detectable loss in seagrass leaf density. Likewise with leaf density, mean seagrass percent cover was similar at Impact and Control locations with 3.3 ± 0.3% and 3.2 ± 0.3% (± SE) respectively. The gross change in percent cover (i.e. difference between D2 and baseline values) at pooled Impact and Control locations was -7.3% and -2.4% respectively. The net change in percent cover at Impact locations relative to baseline and Control locations (i.e. gross change at Impact locations minus gross change at the Control locations) was -4.9%. This represents a relative decrease of 46.3% from average baseline values and exceeds the Level 3 trigger value; loss in seagrass percentage cover greater than the level of detection +10%. A large decrease in percent cover and leaf density of Halophila sp. at the monitoring sites between August and November 2012 accounts for most of the measured decline. Despite the Level 3 trigger exceedance, percent cover and leaf density remained relatively constant between D1 and D2 (9 November to 9 December 2012). Turbidity and light measurements at Woods Inlet, Lee Point and Fannie Bay during the monitoring period indicated no evidence of a turbid plume at these locations from the Project s dredging or spoil disposal activities. Given the highly variable nature in growth and distribution displayed by seagrasses in and around Darwin Harbour, it is difficult to attribute a change in cover or density to a specific cause. Although PAR (light) levels have decreased since baseline sampling at all seagrass sampling locations, an associated decrease in seagrass cover or density was not always observed during sampling. This suggests that other factors, such as smothering from increased suspended sediments from heavy rainfall events or natural seagrass dieback, could also be having an effect on seagrass growth and distribution within the study area. The seagrass trigger exceedance was therefore not attributed to dredging and was considered a result of natural variability between August and November The seagrass trigger values are defined in terms of relative loss during dredging compared to baseline levels. Considering that seagrass percent cover during B3 was low (11% cover), small changes in absolute percent cover can represent large relative change. A 20% relative loss from baseline represents an absolute decrease in seagrass percent cover of only 2% cover, while a 30% relative loss represents an absolute change of only 3% cover. Such values, currently used as management triggers, do not represent ecologically relevant change in view of the natural variability observed during baseline monitoring (June 2012 to August 2012). Prepared for INPEX Page iii

4 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Glossary Term or Acromym Definition B1, B2, B3 Baseline surveys 1, 2, and 3, respectively BACI Benthic CPCe Before After Control Impact On the seafloor Coral Point Count software with Excel extension D1, D2 Dredging surveys 1 and 2: The first and second surveys completed in November and December 2012 after the commencement of dredging activities on 27 August 2012 DGPS DSDMP EIS GPS GO HSE Intertidal LAT MOF NEMP NTU PAR Permanova Photoquadrat Point Data PQP QA/QC SE Differential Global Positioning System Dredging and Spoil Disposal Management Plan Environmental Impact Statement Global Positioning System Geo-Oceans Health Safety Environment The portion of shoreline between low and high tide marks, that is intermittently submerged Lowest Astronomical Tide Modular Offload Facility Nearshore Environmental Monitoring Plan Nephelometric Turbidity Units Photosynthetically Available Radiation Permutational Analysis of Variance Virtual sampling unit of known dimensions within a photograph of the seafloor, used to quantify seagrass density and percent cover Benthic habitat information collected during towed-video surveys and used in the creation of habitat maps Project Quality Plan Quality Assurance/Quality Control Standard error of the mean Prepared for INPEX Page iv

5 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Term or Acromym Subtidal TARP Turbidity WBNA Definition Waters below the low-tide mark Trigger Action Response Plan Turbidity gives an indication of water clarity Workboats Northern Australia Prepared for INPEX Page v

6 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Table of Contents Executive Summary iii Glossary iv 1 Introduction Background Requirement to Monitor Seagrass in Darwin Harbour Summary of Baseline Monitoring Results Objectives 2 2 Methodology Vessels, Safety and Environmental Management Sites, Timing and Frequency of Surveys Drop Camera Assessment of Seagrass Condition Field Methods Image Processing Data Analysis Calculation of Indicators Univariate Analyses Tests of Triggers Quality Assurance/ Quality Control (QA/QC Processes) 8 3 Results General Findings Trigger Assessment Seagrass Percent Cover Seagrass Leaf Density Seagrass Patchiness Epiphytes and Sediment Cover QA/QC Results 24 4 Discussion 25 5 Conclusion 27 6 Acknowledgements 28 7 References 29 Tables Table 2-1 Co-ordinates of drop camera monitoring sites 3 Table 2-2 Sampling dates of seagrass surveys and corresponding dredging activities 5 Table 2-3 Explanation of factors used in the statistical analyses 7 Table 2-4 Terms used in describing the outcomes of the statistical analyses 7 Table 3-1 Table 3-2 Mean and standard error (SE) of percent seagrass cover from data collected during B3, D1 and D2. Blank cells indicate where no data was collected. Bold values indicate treatment means and SE 10 Mean and standard error (SE) of seagrass leaf density (leaves / m 2 ) from data collected during B3, D1 and D2. Blank cells indicate where no data was collected. Bold values indicate treatment means and SE 11 Prepared for INPEX Page vi

7 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Table 3-4 Gross and net change in seagrass percent cover calculated between B3 and D2 surveys 12 Table 3-5 Gross and net change in seagrass leaf density calculated between B3 and D2 surveys indicate that leaf density values at Lee Point were excluded from calculations of mean and SE for B3 13 Table 3-6 Table 3-7 Summary of PERMANOVA for seagrass percent cover, leaf density and patchiness showing the level of significance for each of the monitoring factors. * = P(perm) < 0.05, ** = P(perm) < 0.01, *** = P(perm) <0.001; - = redundant term, ns = not significant, NA = not available because patchiness was calculated at the scale of sites 14 Summary of PERMANOVA for epiphyte and sediment cover showing the level of significance for each of the monitoring factors. * = P(perm) < 0.05, ** = P(perm) < 0.01, *** = P(perm) <0.001; - = redundant term, ns = not significant, NA = not available because factor Site was not present 21 Figures Figure 2-1 Seagrass drop camera monitoring locations 4 Figure 3-1 Mean seagrass percent cover (± SE) for Impact and Control locations during baseline survey 3 (August 2012) and the first two dredging surveys (November and December 2012) 12 Figure 3-2 Mean seagrass leaf density (leaves/m 2, ± SE) for Impact and Control locations during baseline survey 3 (August 2012) and the first two dredging surveys (November and December 2012) 13 Figure 3-3 Mean (±SE) percent cover of Halophila at Impact, Contingency Control and Control locations for baseline and during dredging (A) and sites during D1 and D2 (B) (n = 20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between phases within locations (A) and between surveys within sites (B) 15 Figure 3-4 Mean (±SE) percent cover of Halodule at Impact, Contingency Control and Control sites during D1 and D2 (n = 20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys within each site 16 Figure 3-5 Mean (±SE) percent cover of total seagrass at Impact, Contingency Control and Control sites during D1 and D2 (n = 20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys within each site 16 Figure 3-6 Mean (±SE) leaves per m 2 of Halophila at Impact, Contingency Control and Control locations during D1 and D2 (n=20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys within each site. Leaf density data for Lee Point during D1 were not available 17 Figure 3-7 Mean (±SE) leaves per m 2 of Halodule for baseline and during dredging (A) and at Impact, Contingency Control and Control sites during D1 and D2 (B) (n = 20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys within each site. Leaf density data for Lee Point during D1 were not available18 Figure 3-8 Mean (±SE) leaf density (leaves per m 2 ) of seagrass at Impact, Contingency Control and Control sites during D1 and D2 (n = 20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys, within each site. Data for Lee Point during D1 were not available 19 Figure 3-9 Mean (±SE) percent patchiness of total seagrass cover at Impact, Contingency Control and Control locations during D1 and D2 (n = 3) 20 Figure 3-10 Mean (±SE) epiphyte cover (%) at Impact, Contingency Control and Control sites during D1 and D2 (n = 20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys within each site 22 Figure 3-11 Mean (±SE) of sediment cover on seagrass leaves (%cover of seagrass area) at Impact, Contingency Impact and Control sites during D1 and D2 (n=20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys within each site 23 Prepared for INPEX Page vii

8 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Appendices Appendix A Appendix B Appendix C Appendix D Results of Statistical Analyses QA/QC Results Water Quality PAR Prepared for INPEX Page viii

9 Bimonthly Seagrass Monitoring Report - Dredging Report 2 1 Introduction 1.1 Background INPEX is the operator of the Ichthys Gas Field Development Project (the Project). The Project comprises the development of offshore production facilities at the Ichthys Field in the Browse Basin, some 820 km westsouth-west of Darwin, an 889 km long subsea gas export pipeline (GEP) and an onshore processing facility and product loading jetty at Blaydin Point on Middle Arm Peninsula in Darwin Harbour. To support the nearshore infrastructure at Blaydin Point, dredging works will be carried out to extend safe shipping access from near East Arm Wharf to the new product loading facilities at Blaydin Point, which will be supported by piles driven into the sediment. A trench will also be dredged to seat and protect the GEP for the Darwin Harbour portion of its total length. Dredged material will be disposed at the spoil ground located approximately 12 km north-west of Lee Point. A detailed description of the dredging and spoil disposal methodology is provided in Section 2 of the Dredging and Spoil Disposal Management Plan - East Arm (DSDMP) (INPEX 2012a). 1.2 Requirement to Monitor Seagrass in Darwin Harbour Following an Environmental Impact Statement (EIS) (INPEX 2011), the Project was approved subject to conditions that included monitoring for potential effects of dredging or spoil disposal on local ecosystems (including seagrasses) and potentially vulnerable populations. Sedimentation and increased turbidity has the potential to impact upon seagrasses by limiting the light available for photosynthesis, thus affecting growth rate and ultimately their survival. Studies of impacts of dredging elsewhere in Australia (e.g. in Gladstone, Chartrand et al. 2010) indicate that the level of response and rates of recovery of seagrasses are likely to depend on several factors such as the timing, duration, intensity and scale of the dredging works as well as the type of species affected. A monitoring program was therefore set up to examine the potential impact on seagrasses in and around Darwin Harbour region from dredging and spoil disposal activities associated with the Project. The program was designed to test a number of seagrass health variables against predetermined trigger values, which would have the potential to action dredge management responses. 1.3 Summary of Baseline Monitoring Results In order to determine the range of natural variability in seagrass cover and density at a number of locations in and around Darwin Harbour, three baseline surveys were conducted as part of the monitoring program between 29 May 2012 and 28 August 2012, prior to the start of dredging. Baseline seagrass habitat maps were produced based on towed-video surveys conducted along the Cox Peninsula and along the north-eastern foreshore to east of Lee Point. While habitats along the north-eastern foreshore had previously been mapped, seagrass habitat along the Cox Peninsula had only been inferred from bathymetry data. Seagrass habitat was found between +2.2 m and -0.5 m Lowest Astronomical Tide (LAT) along Cox Peninsula and between +2.2 m and -3.3 m LAT along the north-eastern foreshore. These seagrass habitats occurred on soft sandy sediments and were dominated by Halodule uninervis and Halophila decipiens. General locations of seagrass habitat were consistent with 2010 habitat maps, although the boundaries of seagrass distribution had changed. A large seagrass area offshore from Casuarina Beach had contracted, while meadows at Lee Point had expanded since the 2010 mapping survey. Seagrass condition at all monitoring locations was assessed remotely using a high-definition underwater video drop camera. Baseline surveys revealed a considerable increase in seagrass percent cover and leaf density at all locations except Casuarina. During B1, mean percent cover ranged between 1.9 ± 0.3% and 4.5 ± 0.5% at all locations. By B3, mean percent cover at Fannie Bay, Woods Inlet and Charles Point ranged from 4.8 ± 0.8% to 11.7 ± 1.0%, thus representing an increase by a factor of two to three. Mean percent cover at Lee Point reached 18.6 ± 1.0% by B3, representing a tenfold increase in the three months between June 2012 and August Very few seeds or reproductive structures were found within the sediment (i.e. a total of 4 seed / casings of H. uninervis and 4 fruits / flowers of H. decipiens in 60 samples collected across all locations). The capacity Prepared for INPEX Page 1

10 Bimonthly Seagrass Monitoring Report - Dredging Report 2 for recovery from seed reserves will be assessed after completion of a recovery experiment as described in the Nearshore Environmental Monitoring Plan (NEMP). Broadscale towed video mapping surveys, together with localised drop camera surveys located seagrass habitat boundaries across the study area. Considering the natural temporal and spatial variability in seagrass abundance and cover measured during the baseline period, it was considered that a broadscale mapping technique using towed-video would be more accurate and applicable for monitoring seagrass habitat boundaries. Shoot and leaf density results for Halodule were highly correlated but shoots of Halophila could not be reliably counted from images. In order to assess change in total seagrass density (Halodule and Halophila), as required by the DSDMP, it was determined that density measures should be consistent among both taxa therefore, it was recommended that seagrass density be measured in terms of leaf density for both taxa. Power analyses carried out on B3 data indicated that the level of replication in the monitoring design is sufficient to detect net changes in percent cover of 20% (with a power above 0.9). This indicates that triggers of 20 and 30% change in leaf density, as nominated in the DSDMP, can also be detected for change in percent cover. However, the extremely high level of natural variability observed among baseline surveys indicated that these trigger values do not represent ecologically significant change and may therefore, not provide appropriate support to assess attributability of impacts for effective management (Cardno 2012a). 1.4 Objectives Two components to the Seagrass Monitoring Program are applicable: reactive and informative monitoring. Reactive monitoring is carried out at each location on a routine (two monthly during the dry season and monthly during the wet season) basis unless a trigger is exceeded, attributable to dredging, in which case the frequency of targeted monitoring will increase to monthly and other management responses implemented. The main objective of the reactive component of the Seagrass Monitoring Program is to: > Monitor, trigger responses and report potential impacts to seagrass communities as a result of dredging and spoil disposal activities (Section 7.3.7, DSDMP). The methodology is designed to have sufficient replication to determine whether seagrass health triggers, as outlined in the DSDMP (INPEX 2012a), are exceeded. If triggers are exceeded, this may result in changes to the dredging program as outlined in the Trigger Action Response Plan (TARP), Section of the DSDMP. Informative monitoring is also carried out on a routine basis to improve scientific understanding of the impacts of dredging on the environment. Data collected on informative indicators will also be used for interpretative purposes and may support management decisions using a multiple lines of evidence approach; particularly should reactive triggers be exceeded. The objectives of the Seagrass Monitoring Program during dredging are to: > Detect potential changes in seagrass health and distribution attributable to dredging and disposal activities; and > Provide appropriate data to allow clear and timely determination of exceedances of trigger levels. The Seagrass Monitoring Program has been developed based on the principles of Before After Control Impact (BACI) studies (Underwood 1992), involving regular sampling (during dredging) of seagrasses to determine trends in their condition. These data are collected in parallel with water quality parameters to provide early warning indicators that will aid in minimising impacts to seagrass and assist in a multiple lines of evidence approach to evaluating whether triggers have been exceeded. This report describes the results of the second routine seagrass monitoring survey (Survey D2; 6 to 9 December 2012) following the start of dredging and how these data compare with the baseline (29 May to 28 August 2012) and the first dredging survey (Survey D1; 6 to 9 November 2012). Prepared for INPEX Page 2

11 Bimonthly Seagrass Monitoring Report - Dredging Report 2 2 Methodology 2.1 Vessels, Safety and Environmental Management Field work conducted during Survey D2 was carried out from the MV Gunsafe operated by Workboats Northern Australia (WBNA). All work was completed in accordance with the Project Health Safety and Environment (HSE) Plan. 2.2 Sites, Timing and Frequency of Surveys The locations of the drop camera monitoring sites are given in Table 2-1 and Figure 2-1. The drop camera component of D2 was done on neap tides from 6 to 9 December During this survey, sampling was completed at all sites including Impact locations (Fannie Bay, Woods Inlet, and Lee Point), Contingency Impact locations (East Point and Casuarina Beach) and Control locations (Charles Point East and Charles Point West). Consistent with the methodology described in the NEMP, the Contingency Impact locations (East Point and Casuarina) were treated as Control locations in this survey, as there had been no incursion of a suspended sediment plume (from dredging) into the area. For clarity, East Point and Casuarina will be referred to as Contingency Control locations throughout this report. Table 2-1 Co-ordinates of drop camera monitoring sites Treatment Location Name Site Name Impact Control (Contingency) Control Woods Inlet Fannie Bay Lee Point East Point Casuarina Charles Point West Charles Point East Site Code Latitude ( S) Longitude ( E) Woods Inlet W WI_W Woods Inlet N WI_E Woods Inlet S WI_S Fannie Bay S FB_S Fannie Bay M FB_M Fannie Bay N FB_N Lee Point W2 LP_W Lee Point N LP_E Lee Point M LP_M East Point 1 EP_ East Point 2 EP_ East Point 3 EP_ Casuarina S CAS_S Casuarina M CAS_M Casuarina 4 CAS_ Casuarina 5 CAS_ Casuarina 6 CAS_ Charles Point West 1 CPW_ Charles Point West 2 CPW_ Charles Point West 3 CPW_ Charles Point East 1 CPE_ Charles Point East 2 CPE_ Charles Point East 3 CPE_ Prepared for INPEX Page 3

12 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Figure 2-1 Seagrass drop camera monitoring locations Prepared for INPEX Page 4

13 Bimonthly Seagrass Monitoring Report - Dredging Report 2 A summary of drop camera and towed video surveys to date is given in Table 2-2. Note that the third baseline drop camera survey (26 to 28 August 2012) coincided with the start of Backhoe Dredging (BHD) operations (27 August 2012). As potential impacts from BHD operations on seagrass percent cover and density would not be visible within such a short period of time, data from this baseline survey were considered not to be compromised. Table 2-2 Sampling dates of seagrass surveys and corresponding dredging activities Project Dredging Activities Drop Camera Sampling Dates (2012) Towed Video Sampling Dates (2012) No dredging Baseline 1 29 May to 1 June Baseline 22 May to 2 June 13 to 16 June 12 to 18 June 30 June 28 June to 2 July Backhoe Dredging commenced 27 August 2012 Baseline 2 Baseline 3 27 to 31 July 26 to 28 August Dredging 1 8 to 12 October 23 to 26 October Cutter Suction Dredging commenced 4 November 2012 Dredging 1 Dredging 2 6 to 9 November 6 to 9 December 2.3 Drop Camera Assessment of Seagrass Condition Field Methods Monitoring of seagrass percentage cover and leaf density was done from stills taken from video footage (using a high definition video camera) of transects of the seabed at each site. To obtain video footage of a transect the vessel drifted through the site and the camera was raised and lowered to the seabed every few metres. Generally, 3 to 4 transects were done at each site, yielding a total of between 30 to 36 drops of the camera onto the seabed. Each drop onto the seabed constituted a replicate Image Processing Seagrass percentage cover and leaf density were measured in 20 randomly selected replicates from the set of 30 to 36 images collected at each site. Seagrass percentage cover was calculated using the Coral Point Count with Excel extensions software (CPCe) (Kohler and Gill 2006) by digitally overlaying a virtual photoquadrat (scaled to 40 cm x 20 cm) containing 60 random points on each captured video frame (replicate) and recording the type of seagrass (where present) or the substratum under each point. From these data points, the percentage cover of seagrasses within a quadrat was determined. Leaf counts of each seagrass species were made within quadrats (800 cm 2 surface area) and these data were converted to leaf density. Other data obtained and analysed for this report included the percentage cover of epiphytic growth and the cover of sediment that had settled on seagrass leaves within each quadrat. 2.4 Data Analysis Calculation of Indicators The following indicators were analysed from the drop camera surveys: > Seagrass leaf density was calculated by dividing the number of leaves counted within each photoquadrat by the surface area of the quadrat (800 cm2); > Seagrass percent cover was determined for each photoquadrat as the fraction of CPCe points overlaying seagrass material to the total number of points; > Epiphyte percent cover was determined for each photoquadrat as the fraction of CPCe points overlaying epiphytic material to the total number of points; Prepared for INPEX Page 5

14 Bimonthly Seagrass Monitoring Report - Dredging Report 2 > Sediment cover on seagrass was determined for each photoquadrat as the fraction of CPCe points overlaying sediment covered leaves to the total number of points overlaying seagrass; and > Percent patchiness was defined as the percentage of quadrats within a particular site that did not contain any seagrass, i.e. the number of empty quadrats divided by the total number of quadrats within a site Univariate Analyses Univariate permutational analysis of variance (PERMANOVA) was used to examine differences in percentage cover and leaf counts of seagrasses between B3 and D1 and D2 among and within locations sampled during both surveys. This analysis builds on the analyses in the Baseline Report (Cardno 2012a) and Dredging Report 1 (Cardno 2012b). The PERMANOVA routine was performed using Permanova+ in Primer v6 on dissimilarity matrices created using Euclidian distance measures. Five factors were used for each of the PERMANOVA tests: > Phase Fixed and orthogonal with 2 levels (Before and During); > Survey Random and nested within Phase with 3 levels (Before: B3; During:D1 and D2); > Treatment Fixed and orthogonal with 2 levels (Impact and Control); > Location Random and nested within Treatment with 7 levels (Impact: Fannie Bay, Lee Point and Woods Inlet; Control: Casuarina Beach, East Point, Charles Point East and Charles Point West); and > Site Random and nested within Location with 23 levels (3 sites at all locations except for Casuarina Beach, which had 5). Variables analysed included: > Percent cover of Halophila; > Percent cover of Halodule; > Total seagrass cover; > Leaf counts of Halophila; > Leaf counts of Halodule; and > Total leaf counts seagrasses. Potential impacts of dredging (i.e. rejection of null hypotheses) were interpreted through a series of statistically significant interactions (Table 2-3 and Table 2-4). Significant results for the terms Phase x Treatment, Phase x Location, Survey x Treatment or Survey x Location may indicate an effect of dredging. Where significant interactions or main factors effects were detected, post hoc permutational t- tests using Permanova+ were done to identify the levels of factors in which differences occurred. No multiple test corrections were applied to t-test results, consistent with a conservative statistical approach and consistent with the Precautionary Principle. To gain an understanding of how epiphytic growth and potential smothering of seagrass by suspended sediments has changed since the end of baseline monitoring, the cover of epiphytes and sediment on seagrass was also analysed using PERMANOVA. Data from the Contingency Control locations (East Point and Casuarina Beach) were pooled with the other Control locations (Charles Point East and Charles Point West), as turbidity measurements indicated that there was no suspended sediment plume incursion into these locations. This approach is consistent with statistical analyses described in the NEMP. Prepared for INPEX Page 6

15 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Table 2-3 Explanation of factors used in the statistical analyses Component of Variation Interpretation Phase Treatment Survey (Phase) Location (Treatment) Site (Location(Treatment)) Phase x Treatment Phase x Location (Treatment) Phase x Site (Location (Treatment)) Survey (Phase) x Treatment Survey (Phase) x Location (Treatment) Survey(Phase) x Site (Location(Treatment)) Residual Indicates a difference between Phases independent of Treatment. Indicates a difference between Impact and Control Treatments independent of Phase. Indicates a difference between Surveys within each Phase. Indicates large scale variation: a difference among Locations within each Treatment. Indicates small-scale variation: a difference among Sites within one or more Locations independent of Phase. Indicates that differences between Phases are dependent on the Treatment and vice versa. Indicative of an impact due to dredging occurring at the scale of all Impact locations. Indicates that the effect of Phase is dependent on the Location within a Treatment and vice versa. Indicative of an impact due to dredging occurring at the scale of Location within the Impact Treatment. Indicates that the effect of Phase is dependent on Sites within Locations and vice versa. Indicative of an impact due to dredging occurring at the scale of Sites within Impact locations. Indicates that differences between Surveys are dependent on the Treatment and vice versa. Indicative of an impact due to dredging occurring at the scale of the Impact Treatment. Indicates that differences between Surveys are dependent on Location and vice versa. Indicative of an impact due to dredging occurring at the scale of Location within the Impact Treatment. Indicates that differences between Surveys are dependent on Sites within Locations and vice versa. Indicative of an impact due to dredging occurring at the scale of sites within Impact Locations. This term is a measure of the variation in the data not explained by the variation attributed to the main factors in the experimental model (i.e. Phase, Survey, Treatment, Locations, Sites and their associated interactions). Table 2-4 Terms used in describing the outcomes of the statistical analyses Outcome (code) Interpretation Redundant term (-) Non-significant (ns) Significant (asterisks) A term becomes redundant if a lower order interaction including that term is significant. Non-significant describes the convention by which a statistical comparison is deemed not to be an actual effect (i.e. accept the null hypothesis that there is no effect). Here the cut-off point was set at P > The statistical comparison indicating the presence of an actual effect. These signify the probability (P) of an effect being considered to actually occur. Here, * = P < 0.05, ** = P < 0.01, *** = P < These indicate that the likelihood of an effect occurring by chance alone (and therefore not explained by the factor being considered) would be 5 in 100, 1 in 100, or 1 in 1000, respectively. By convention, significant terms are indicated in tables in bold typeface. Prepared for INPEX Page 7

16 Bimonthly Seagrass Monitoring Report - Dredging Report Tests of Triggers Gross changes in percentage cover and leaf density were calculated for each replicate quadrat at all Impact sites. > G i = (X Survey, i X Baseline Avg. ) where X Survey, i is the percentage cover / leaf density of quadrat i measured in the current survey (D2), and X Baseline Avg. is the average percentage cover / leaf density of the site during the last Baseline survey (i.e. B3). Net changes in percentage cover and leaf density were calculated for each replicate quadrat at Impact sites. > N i (Net change) = G i G Ref Avg. where G i is the gross change in percentage cover/leaf density at pooled Impact sites and G Ref Avg. is the average gross change in percentage cover/leaf density at pooled Control sites. N i is the value used to assess the seagrass health triggers (20% and 30% net change in seagrass cover and leaf density, respectively). To assess whether observed seagrass percentage cover or leaf density exceeds the Level 2 or Level 3 trigger levels, a statistical test was undertaken. A t-test of two independent means was done to compare average gross change in seagrass cover or leaf density between the Control and Impact locations. The level of significance was set at the 95% level. The Control sites were pooled and weighted (total number of quadrats = 240), increasing the degrees of freedom of the analyses and, therefore, increasing the power. t = total variance = 2.5 Quality Assurance/ Quality Control (QA/QC Processes) The QA/QC processes followed in the field and in the office by all Project personnel (i.e. field staff, office staff), in order to complete the scope of work to a consistent and high quality, are described in details in the Method Statement and in the Work Instructions (Cardno 2012a). Results of QC procedures are given in Appendix C. Prepared for INPEX Page 8

17 Bimonthly Seagrass Monitoring Report - Dredging Report 2 3 Results 3.1 General Findings Total mean seagrass cover within Impact and Control locations was similar among all surveys and varied from 2.7 ± 0.2% to 11.0 ± 0.7% cover in Impact locations and from 3.2 ± 0.3% to 12.3 ± 0.8% in Control locations. Total mean seagrass cover during survey D2 was 3.3 ± 0.3% and 3.2 ± 0.3% at Impact and Control locations respectively, and was lower compared to B3 (11.0 ± 0.7 % and 10.1 ± 0.7%, for Impact and Control locations respectively) but similar to B1 (2.7 ± 0.2% and 3.2 ± 0.3%, for Impact and Control locations respectively). Across all surveys, mean percent cover of Halophila (decipiens) remained generally low at Control locations, with values ranging between 0.6 ± 0.2% and 1.8 ± 0.3% cover, while values at Impact locations were higher and ranged between 0.1 ± 0.1% and 6.4 ± 0.6% (Table 3-1A). Mean percent cover of Halodule (uninervis) ranged from 2.6 ± 0.2% to 9.2 ± 0.8% cover at Control locations and from 3.2 ± 0.3% to 4.6 ± 0.5% at Impact locations and was greatest during B3 at Control locations (Table 3-1B). Seagrass beds at monitoring locations were generally dominated by Halodule except at Lee Point and East Point. At Lee Point the percent cover of Halophila exceeded that of Halodule by a factor of 2 to 13 between B2 and survey D2, while Halodule was quasi-absent from East Point (Table 3-1A and Table 3-1B). Consistent with percent cover results, total mean seagrass leaf density at Impact and Control locations was similar among surveys and varied from 324 ± 23 leaves/m 2 to 1,969 ± 108 leaves/m 2 in Impact locations and from 471 ± 27 leaves/m 2 to 1,380 ± 63 leaves/m 2 in Control locations. Total mean seagrass leaf density during D2 was 557 ± 34 leaves/m 2 and 556 ± 31 leaves/m 2 at Impact and Control locations respectively. These values were similar to those observed at Impact locations but lower to those at Control locations during D1. Prepared for INPEX Page 9

18 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Table 3-1 Mean and standard error (SE) of percent seagrass cover from data collected during B3, D1 and D2. Blank cells indicate where no data was collected. Bold values indicate treatment means and SE A. Halophila decipiens B3 D1 D2 Location Mean SE Mean SE Mean SE Impact Fannie Bay Lee Point Woods Inlet Control Casuarina East Point Charles Point East Charles Point West Total B. Halodule uninervis B3 D1 D2 Location Mean SE Mean SE Mean SE Impact Fannie Bay Lee Point Woods Inlet Control Casuarina East Point Charles Point East Charles Point West Total Prepared for INPEX Page 10

19 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Table 3-2 Mean and standard error (SE) of seagrass leaf density (leaves / m 2 ) from data collected during B3, D1 and D2. Blank cells indicate where no data was collected. Bold values indicate treatment means and SE A. Halophila decipiens B3 D1 D2 Location Mean SE Mean SE Mean SE Impact Fannie Bay Lee Point Woods Inlet Control Casuarina East Point Charles Point East Charles Point West Total B. Halodule uninervis B3 D1 D2 Location Mean SE Mean SE Mean SE Impact Fannie Bay Lee Point Woods Inlet Control Casuarina East Point Charles Point East Charles Point West Total Prepared for INPEX Page 11

20 % Bimonthly Seagrass Monitoring Report - Dredging Report Trigger Assessment Total seagrass percent cover (Halodule and Halophila combined) at pooled Impact locations decreased from 10.7 ± 0.6% to 3.3 ± 0.3% between August to December 2012, while total seagrass percent cover at pooled Control locations (including Contingency Control locations) showed little change (5.6 ± 0.4% to 3.2 ± 0.3%) (Figure 3-1). As a result, Impact locations recorded a decrease of 69% cover between B3 and D2. This represents a relative decrease of 46% from average B3 values and exceeds the Level 3 trigger value of level of detection (20%) plus 10%. Trigger t-tests were significant for Lee Point, Woods Inlet and for pooled Impact locations (Table 3-3). Table 3-4 Gross and net change in seagrass percent cover calculated between B3 and D2 surveys Location B3 D2 Gross Change Net Change % Relative to Baseline t-test p- value Impact Fannie Bay 6.6 ± ± % Lee Point 18.6 ± ± % Woods Inlet 6.7 ± ± % <0.001 Pooled Impact 10.7 ± ± % <0.001 Control Casuarina 2.1 ± ± Charles Point East 11.7 ± ± Charles Point West 6.4 ± ± East Point 4.8 ± ± Pooled Control 5.6 ± ± Impact Fannie Bay Impact Lee Point Impact Woods Inlet Control Casuarina Control Charles Point East Control Charles Point West Control East Point B3 D1 D2 Figure 3-1 Mean seagrass percent cover (± SE) for Impact and Control locations during baseline survey 3 (August 2012) and the first two dredging surveys (November and December 2012) Prepared for INPEX Page 12

21 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Total leaf density (Halodule and Halophila combined) decreased from 1,969 ± 108 leaves/m 2 to 557 ± 34 leaves/m 2 at pooled Impact locations. Similarly, total seagrass leaf density decreased at pooled Control locations (including Contingency Control locations) but the decrease was smaller in magnitude compared to pooled Impact locations (from 1,116 ± 71 leaves/m 2 to 556 ± 31 leaves/m 2 ) (Figure 3-2). As a result the net change in seagrass density at Impact locations was -852 leaves/m 2 and represented a 43% relative decrease from average B3 values (Table 3-5). This value exceeds the Level 3 trigger value of >30% relative loss. The trigger t-tests were significant for Lee Point, Woods Inlet and for pooled Impact locations (Table 3-4). Table 3-5 Gross and net change in seagrass leaf density calculated between B3 and D2 surveys indicate that leaf density values at Lee Point were excluded from calculations of mean and SE for B3 Location B3 D2 Gross Change Net Change % Relative to B3 t-test p- value Impact Fannie Bay 1,081 ± ± % Lee Point 3,665 ± ± 59-2,996-2, % Woods Inlet 1,140 ± ± % <0.001 Pooled Impact 1,969 ± ± 34-1, % <0.001 Control Casuarina 547 ± ± Charles Point East 1,574 ± ± Charles Point West 934 ± ± East Point 1,711 ± ± 87-1,357 Pooled Control 1,116 ± ± Number of leaves/m Impact Fannie Bay Impact Lee Point Impact Woods Inlet Control Casuarina Control Charles Point East Control Charles Point West Control East Point B3 D1 D2 Figure 3-2 Mean seagrass leaf density (leaves/m 2, ± SE) for Impact and Control locations during baseline survey 3 (August 2012) and the first two dredging surveys (November and December 2012) Prepared for INPEX Page 13

22 Bimonthly Seagrass Monitoring Report - Dredging Report Seagrass Percent Cover Univariate analyses indicated that there was no clear pattern of changes in the cover of Halophila, Halodule and total seagrass (Halophila and Halodule combined) during D2 that could be attributed to the Project s dredging activities (Table 3-6, Phase x Treatment interaction). Most of the variability in the cover of Halophila, Halodule and the total seagrass was observed at the smaller temporal and spatial scale (i.e. between D1 and D2 and among Sites within each Location), as indicated by the significant interaction between the factors Survey and Site (Table 3-6). Pair-wise comparisons at the lowest spatial scale (i.e. site) indicated that the cover of Halophila, Halodule and the total seagrass decreased in several sites from D1 to D2 (Figure 3-3B, Figure 3-4 and Figure 3-5; Appendix A). This pattern was clearer for Halophila, which cover decreased at all Impact locations after the dredging phase but not at Control or Contingency Control locations (Figure 3-3A). Overall, the percent cover of single seagrass species and total seagrass cover decreased between before and during dredging Phases and this decrease was similar at Impact, Contingency Control and Control locations (Figure 3-3B, Figure 3-4 and Figure 3-5). Table 3-6 Source of Variation Summary of PERMANOVA for seagrass percent cover, leaf density and patchiness showing the level of significance for each of the monitoring factors. * = P(perm) < 0.05, ** = P(perm) < 0.01, *** = P(perm) <0.001; - = redundant term, ns = not significant, NA = not available because patchiness was calculated at the scale of sites Halophila % Cover Halodule % Cover Total % Cover Halophila Leaf Density Halodule Leaf Density Total Leaf Density % Patchiness Phase ns ns Treatment ns ns ns - - ns ns Survey (Phase) Location (Treatment) - - * ns Phase x Treatment ns ns ns ns * ns ns Site (Loc (Treat)) NA Phase x Loc (Treat) ** ns ns ns ns ns ns Survey (Phase) x Treat ns ns ns ns ns ns ns Phase x Site (Loc (Treat)) ns ** * ** * ** NA Survey (Phase) x Loc (Treat) * * ns ** *** *** ns Survey (Phase) x Site (Loc(Treat)) ** ** *** ns *** ** NA Prepared for INPEX Page 14

23 Bimonthly Seagrass Monitoring Report - Dredging Report 2 (A) (B) Figure 3-3 Mean (±SE) percent cover of Halophila at Impact, Contingency Control and Control locations for baseline and during dredging (A) and sites during D1 and D2 (B) (n = 20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between phases within locations (A) and between surveys within sites (B) Prepared for INPEX Page 15

24 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Figure 3-4 Mean (±SE) percent cover of Halodule at Impact, Contingency Control and Control sites during D1 and D2 (n = 20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys within each site Figure 3-5 Mean (±SE) percent cover of total seagrass at Impact, Contingency Control and Control sites during D1 and D2 (n = 20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys within each site Prepared for INPEX Page 16

25 Bimonthly Seagrass Monitoring Report - Dredging Report Seagrass Leaf Density Univariate analyses indicated that there was no clear pattern of changes in the cover of Halophila and total seagrass that could be attributed to the Project s dredging activities (Table 3-6, Phase x Treatment interaction). Most of the variability in the leaf density was observed at the smaller temporal and spatial scales (i.e. among Sites within each Location), as indicated by the significant interaction between the factors Survey and Site (Table 3-6). Pair-wise comparisons at the lowest spatial scale (i.e. Site) indicated that the cover of Halophila, Halodule and the total seagrass decreased in several sites (Figure 3-7B, Figure 3-8; Appendix A) and locations (Figure 3-6) from D1 to D2. In contrast, the significant Phase x Treatment interaction term observed for the density of Halodule leaves (Table 3-6) indicated the occurrence of changes in leaf density within a Phase which were dependent on Treatment (Figure 3-7A). Specifically, the density of Halodule at Impact locations decreased after dredging commenced and had similar values to Control locations (Figure 3-7A). However, post hoc comparisons did not reveal any difference in the density of Halodule leaves, independently of whether comparisons were done between Phases (i.e. Before versus During) or Treatment (i.e. Control versus Impact) (Appendix A). Overall, the leaf density of single seagrass species and total seagrass cover decreased between before and during dredging Phases and this decrease was similar at Impact, Contingency Control and Control locations (Figure 3-6, Figure 3-7B and Figure 3-8). Figure 3-6 Mean (±SE) leaves per m 2 of Halophila at Impact, Contingency Control and Control locations during D1 and D2 (n=20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys within each site. Leaf density data for Lee Point during D1 were not available Prepared for INPEX Page 17

26 Bimonthly Seagrass Monitoring Report - Dredging Report 2 (A) (B) Figure 3-7 Mean (±SE) leaves per m 2 of Halodule for baseline and during dredging (A) and at Impact, Contingency Control and Control sites during D1 and D2 (B) (n = 20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys within each site. Leaf density data for Lee Point during D1 were not available Prepared for INPEX Page 18

27 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Figure 3-8 Mean (±SE) leaf density (leaves per m 2 ) of seagrass at Impact, Contingency Control and Control sites during D1 and D2 (n = 20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys, within each site. Data for Lee Point during D1 were not available 3.5 Seagrass Patchiness Patchiness is defined as the number of quadrats within a particular site that did not contain any seagrass, expressed as a percentage of the total number of quadrats sampled at that site (i.e. the larger the number of empty quadrats, the greater level of patchiness of seagrass). The average seagrass patchiness at all locations during D1 and D2 ranged between 0 and 60%. On average, D2 had slightly higher values (17 ± 6%) compared to B3 and D1 (13 ± 5% for both). No significant differences in the level of seagrass patchiness were detected either between the two surveys or among treatments (Table 3-5; Figure 3-9). Prepared for INPEX Page 19

28 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Figure 3-9 Mean (±SE) percent patchiness of total seagrass cover at Impact, Contingency Control and Control locations during D1 and D2 (n = 3) Prepared for INPEX Page 20

29 Bimonthly Seagrass Monitoring Report - Dredging Report Epiphytes and Sediment Cover Univariate analyses indicated that there was no clear pattern of changes in the cover of epiphytes and sediment during D2 due to the Treatment interaction (Table 3-7, Phase x Treatment interaction). Most of the variability for these two variables was observed at the smaller temporal and spatial scale (i.e. between D1 and D2 and among Sites within each Location) (Figure 3-10 and Figure 3-11), as indicated by the significant interaction between the factors Survey x Site and Survey x Location (Table 3-7). Pair-wise comparisons of these interaction terms indicated that both seagrass epiphytes and sediment cover decreased in several sites from D1 to D2 (Figure 3-10 and Figure 3-11; Appendix A). Table 3-7 Summary of PERMANOVA for epiphyte and sediment cover showing the level of significance for each of the monitoring factors. * = P(perm) < 0.05, ** = P(perm) < 0.01, *** = P(perm) <0.001; - = redundant term, ns = not significant, NA = not available because factor Site was not present Source of Variation % Epiphyte cover % Sediment cover Phase NS NS Treatment NS NS Survey (Phase) - - Location (Treatment) - NS Phase x Treatment NS NS Site (Loc (Treat)) - - Phase x Loc (Treat) NS NS Survey (Phase) x Treat NS NS Phase x Site (Loc (Treat)) NS NS Survey (Phase) x Loc (Treat) ** NS Survey (Phase) x Site (Loc (Treat)) *** *** Prepared for INPEX Page 21

30 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Figure 3-10 Mean (±SE) epiphyte cover (%) at Impact, Contingency Control and Control sites during D1 and D2 (n = 20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys within each site Prepared for INPEX Page 22

31 Bimonthly Seagrass Monitoring Report - Dredging Report 2 Figure 3-11 Mean (±SE) of sediment cover on seagrass leaves (%cover of seagrass area) at Impact, Contingency Impact and Control sites during D1 and D2 (n=20). Dotted lines represent mean location values observed during B3. * indicates significant (at P(perm) < 0.05) differences between surveys within each site Prepared for INPEX Page 23

32 Bimonthly Seagrass Monitoring Report - Dredging Report QA/QC Results The QA/QC results for training CPCe operators and checking data are presented in Appendix B. Prepared for INPEX Page 24

33 Bimonthly Seagrass Monitoring Report - Dredging Report 2 4 Discussion Backhoe dredging operations for the Project began on 27 August 2012 in the MOF area near Blaydin Point in the upper East Arm of Darwin Harbour. The more intensive phase of Cutter Suction Dredging began on 4 November Within this reporting period the cumulative volume of material dredged was approximately 819,000 m 3. Dredge spoil material has been disposed of in the spoil ground located 12 km north-west of Lee Point. Generally, Charles Point and Woods Inlet were characterised by greater turbidity levels, with mean daily turbidity ranging between 7.5 and 10.2 Nephelometric Turbidity Units (NTU) during the survey period (Appendix C). Casuarina recorded the lowest turbidity levels with a mean turbidity of 3.1 NTU (Appendix C). Water temperature at all sites monitored ranged between 30.8º C and 32.8º C during the survey period (Appendix C). No exceedances of the Level 1 Seagrass Wet Season turbidity trigger levels attributable to dredging had occurred at Impact locations (Woods Inlet, Fannie Bay and Lee Point) over the reporting period (INPEX 2012a). Subsequently, the seagrass Level 3 trigger exceedances reported here are attributed to natural variability and not to the Project s dredging and/or spoil disposal activities. Although not a specific trigger variable as set out in the DSDMP (INPEX 2012a), PAR (Photosynthetically Available Radiation) can also be predominant when considering potential impacts to seagrasses from dredging. These values are influenced by the level of turbidity, water depth, tide, cloud cover and daylight cycle and can be important in structuring seagrass assemblages and their growth (Zimmerman 2006, Hillman et al. 1989). PAR and other water quality variables that have been recorded throughout the monitoring program to date are detailed in Cardno (2012c, 2012d). Summary PAR results that have been recorded within the vicinity of the seagrass sampling sites are also presented in Appendix D. During the period between 1 November and 31 December 2012, East Point (Eas_01) had recorded the largest mean PAR of 117 mol/m 2 /s, whereas Charles Point (CP_2) and Woods Inlet (WOD_01) recorded the lowest PAR, each with 52 mol/m 2 /s. Generally, mean PAR levels have decreased at all seagrass monitoring locations since B3 (Appendix D), although it is difficult to determine if the decrease in PAR is the sole determinant for seagrass loss at all sites sampled. For example, some sites that have recorded a decrease in PAR readings over the survey period have not shown an associated loss of seagrass. This was evident at sites such as FB_N, CAS_6, EP_2 and CPW_2, which all recorded a higher seagrass percent cover compared to that observed in B3. Other factors, such as smothering by increased suspended sediment associated with Wet season rainfall, natural seasonal dieback or potential physical removal by large tidal movements during spring tide events could have combined with decreased PAR values in a complex manner and influenced seagrass growth and distribution in and around Darwin Harbour. Given that the seagrass species found within the study area are highly ephemeral, linking changes in their cover and distribution with other environmental variables is difficult. Notwithstanding this, the decreasing trend of PAR values since baseline surveys appears to be contributing somewhat to the general patterns observed during the latest seagrass monitoring results. After the widespread decrease in seagrass cover and density observed between the B3 (August 2012) and D1 (November 2012), the change in seagrass percent cover and density appeared to stabilise during D2. Although there were some smaller spatial scale differences in percent cover and density between D1 and D2, the variability displayed for the Impact locations was similar to that observed within the Control locations. In addition, the majority of change between the two dredging surveys was well within the natural range detected during the baseline monitoring phase. Further, the spatial and temporal variability found during baseline surveys indicates that the observed decrease of 4.9% cover at Impact locations lies within the range of expected natural variability (i.e. an average change of 8% cover at Impact locations during baseline). Given this, the trigger exceedances described in this report are due to the decrease in seagrass cover and density that was observed between B3 and D1 and are not likely to be due to the Project s dredging and spoil disposal activities. Prepared for INPEX Page 25

34 Bimonthly Seagrass Monitoring Report - Dredging Report 2 At the species level, it appeared that Halophila was continuing with its perceived seasonal die-off pattern, with most sites (both Control and Impact) that previously contained the seagrass showing very little cover during D2. No clear pattern was seen for Halodule however, with some sites showing significant differences in cover (increases and decreases) between the two dredging surveys, whilst others showed very little difference. These patterns were irrespective of whether the site was from a Control or Impact location. Prepared for INPEX Page 26

35 Bimonthly Seagrass Monitoring Report - Dredging Report 2 5 Conclusion Despite the Level 3 Seagrass Wet Season trigger exceedance, changes in percent cover and leaf density in the monitoring period, 10 November to 9 December 2012, were well within the range of natural change observed during baseline monitoring. Turbidity measurements at Woods Inlet, Lee Point and Fannie Bay indicated that no suspended sediment plume entered these locations from either dredging or spoil disposal activities during the monitoring period. The trigger exceedance was therefore not attributed to the Project s dredging and spoil disposal activities but was likely due to natural variability. The seagrass trigger values are defined in terms of relative loss compared to baseline levels. Considering that seagrass percent cover during B3 was low (11% cover), small changes in absolute percent cover can represent large relative change. A 20% relative loss from baseline represents an absolute decrease in seagrass percent cover of only 2% cover, while a 30% relative loss represents an absolute change of only 3% cover. Such values, currently used as management triggers, do not represent ecologically relevant change in view of the natural variability observed during baseline monitoring (June to August 2012). Prepared for INPEX Page 27

36 Bimonthly Seagrass Monitoring Report - Dredging Report 2 6 Acknowledgements This report was written by Isabel Jimenez, Andrea Nicastro, and Brendan Alderson. Yesmin Chikhani assisted with table production. The report was reviewed by Craig Blount. Field work was done by Daniel Aveling and Yesmin Chikhani. CPCe analysis was done by Kelley Whitaker, Kelly Davis, Yesmin Chikhani, Andrea Nicastro, Sean Smith, Molly Scott, Sean Smith and Alanna Murdoch. Prepared for INPEX Page 28

37 Bimonthly Seagrass Monitoring Report - Dredging Report 2 7 References Cardno (2012a). Seagrass Monitoring Program Baseline Report. Report for INPEX, Cardno Ecology Lab Pty Ltd, Sydney. Cardno (2012b). Bimonthly Seagrass Monitoring Report Dredging Report 1. Report for INPEX, Cardno Ecology Lab Pty Ltd, Sydney. Cardno (2012c). Water Quality Monitoring Program Baseline Report. Report for INPEX, Cardno (NSW/ACT) Pty Ltd, Sydney. Cardno (2012d). Bimontly Water Quality & Subtidal Sedimentation Report Dredging Report 1 - Ichthys Nearshore Environmental Monitoring Program. Report for INPEX, Cardno (NSW/ACT) Pty Ltd, Sydney. Chartrand, K.M., McKenna, S.A., Petrou, K., Jimenez-Denness, I., Franklin, J., Sankey, T.L., Hedge, S.A., Rasheed, M.A. and Ralph, P.J. (2010) Port Curtis Benthic Primary Producer Habitat Assessment and Health Studies Update: Interim Report December DEEDI Publication. Fisheries Queensland, Cairns, 128 pp. Geo Oceans (2011). Ichthys Gas Field Development Project: Benthic Habitat Mapping of the Darwin region Methods of Data Collection, Collation, and Map Production. Ichthys Technical Appendix S6. Hillman, K., Walker, D.I., Larkum, A.W.D. and McComb, A.J. (1989). Productivity and Nutrient Limitation. In Larkum A.W.D., McComb A.J. and Shepherd S.A. (Eds.), Biology of Seagrasses (pp ) Amsterdam: Elsevier. INPEX (2011). Ichthys Gas Field Development Project, Supplement to the Draft Environmental Impact Statement INPEX (2012a). Dredging and Spoil Disposal Management Plan. 512 pp INPEX (2012b). Exceedance Attributability and Implementation Report: Level 3 Seagrass Trigger 19 November Kohler, K.E. and Gill, S.M. (2006). Coral Point Count with Excel extensions (CPCe): A Visual Basic program for the determination of coral and substrate coverage using random point count methodology. Comparative. Geoscience. 32: Underwood, A. J. (1992). Beyond BACI: the detection of environmental impacts on populations in the real, but variable, world. Journal of Experimental Marine Biology and Ecology 161: Zimmerman, R.C., (2006). Light and Photosynthesis in Seagrass Meadows. In Larkum, W.D., Orth, R.J. and Duarte, C.M. (Eds), Seagrasses: Biology, Ecology and Conservation ( ). Netherlands: Springer. Prepared for INPEX Page 29

38 Ichthys Nearshore Environmental Monitoring Program Bimonthly Seagrass Monitoring Report - Dredging Report 2 APPENDIX A RESULTS OF STATISTICAL ANALYSES Prepared for INPEXInsert date Page A-4

39 A. Results of PERMANOVA testing for differences in the percent cover of Halophila. Significant (P(perm) < 0.05) terms in bold. Monte Carlo ( MC ) simulation was used to calculate P values where unique permutations < 100. Source df SS MS Pseudo-F P(perm) Phase Treatment Survey(Phase) Location(Treatment) PhasexTreatment Site(Location(Treatment)) PhasexLocation(Treatment) Survey(Phase)xTreatment PhasexSite(Location(Treatment)) Survey(Phase)xLocation(Treatment) Survey(Phase)xSite(Location(Treatment)) Residual Total Pairwise Comparison Term 'SuxLo(Tr)' for pairs of levels of factor 'Survey' (DC01 Vs DC02) Groups t P Impact Fannie Bay MC Lee Pooint MC Woods Inlet Negative Contingency Casuarina MC East Point Control Charles Point East Denominator is 0 Charles Point West MC Prepared for INPEX Page A-1

40 Pairwise Comparison Su(Ph)xSi(Lo(Tr))' for pairs of levels of factor 'Survey' (DC01 Vs DC02) Groups t P Impact Fannie Bay FB_N Denominator is 0 FB_M MC FB_S Denominator is 0 Lee Point LP_E MC LP_M Denominator is 0 LP_W MC Woods Inlet WI_E MC WI_S MC WI_W MC Contingency Casuarina CAS_ MC CAS_5 CAS_6 Denominator is 0 Denominator is 0 CAS_M MC CAS_S MC East Point EP_ MC EP_ MC EP_ MC Control Charles Point East CPE_1 CPE_2 CPE_3 Denominator is 0 Denominator is 0 Denominator is 0 Charles Point West CPW_ MC CPW_2 CPW_3 Denominator is 0 Denominator is 0 Prepared for INPEX Page A-2

41 B. Results of PERMANOVA testing for differences in the percent cover of Halodule. Significant (P(perm) < 0.05) terms in bold. Monte Carlo ( MC ) simulation was used to calculate P values where unique permutations < 100. Source df SS MS Pseudo-F P(perm) Phase Treatment Survey(Phase) Location(Treatment) PhasexTreatment Site(Location(Treatment)) PhasexLocation(Treatmentr) Survey(Phase)xTreatment PhasexSite(Location(Treatment)) Survey(Phase)xLocation(Treatment) Survey(Phase)xSite(Location(Treatment)) Residual Total Pairwise Comparison Term 'SuxLo(Tr)' for pairs of levels of factor 'Survey' (DC01 Vs DC02) Groups t P Impact Fannie Bay Lee Pooint Woods Inlet MC Contingency Casuarina East Point MC Control Charles Point East Charles Point West Prepared for INPEX Page A-3

42 Pairwise Comparison Term 'Su(Ph)xSi(Lo(Tr))' for pairs of levels of factor 'Survey' (DC01 Vs DC02) Groups t P Impact Fanny Bay FB_N FB_M FB_S MC Lee Point LP_E MC LP_M MC LP_W Woods Inlet WI_E MC WI_S WI_W MC Contingency Casuarina CAS_ MC CAS_ MC CAS_ MC CAS_M MC CAS_S MC East Point EP_ MC EP_2 Denominator is 0 EP_ MC Control Charles Point East CPE_ CPE_ CPE_ Charles Point West CPW_ MC CPW_ CPW_ MC Prepared for INPEX Page A-4

43 C. Results of PERMANOVA testing for differences in the total percent cover of seagrass. Significant (P(perm) < 0.05) terms in bold. Monte Carlo ( MC ) simulation was used to calculate P values where unique permutations < 100. Source df SS MS Pseudo-F P(perm) Phase Treatment Survey(Phase) Location(Treatment) PhasexTreatment Site(Location(Treatment)) PhasexLocation(Treatment) Survey(Phase)xTreatment PhasexStei(Location(Treatment)) Survey(Phase)xLocation(Treatment) Survey(Phase)xSite(Location(Treatm Residual Total Pairwise Comparison Term 'Su(Ph)xSi(Lo(Tr))' for pairs of levels of factor 'Survey' (DC01 Vs DC02) Groups t P Impact Fanny Bay FB_N FB_M FB_S Lee Point LP_E LP_M MC LP_W Woods Inlet WI_E MC WI_S WI_W MC Contingency Casuarina CAS_ MC CAS_ CAS_ MC CAS_M CAS_S MC East Point EP_ MC EP_ EP_ Control Charles Point East CPE_ CPE_ CPE_ Charles Point West CPW_ MC CPW_ CPW_ MC Prepared for INPEX Page A-5

44 D. Results of PERMANOVA testing for differences in the density of Halophila leaves. Significant (P(perm) < 0.05) terms in bold. Monte Carlo ( MC ) simulation was used to calculate P values where unique permutations < 100. Source df SS MS Pseudo-F P(perm) Phase 1 9.5E E Treatment 1 2.5E E Survey(Phase) 1 1.1E E Location(Treatment) 5 3.2E E PhasexTreatment 1 1.8E E Site(Location(Treatment)) E E PhasexLocation(Treatment) 5 1.4E E Survey(Phase)xTreatment 1 1.1E E PhasexSite(Location(Treatment)) E E Survey(Phase)xLocation(Treatment) 4 1.2E E Survey(Phase)xSite(Location(Treatment)) E E Residual E E+05 Total E+09 Pairwise Comparison Term 'SuxLo(Tr)' for pairs of levels of factor 'Survey' (DC01 Vs DC02) Groups t P Impact Fannie Bay MC Lee Point Woods Inlet Denominator is 0 Contingency Casuarina MC East Point Control Charles Point East Denominator is 0 Charles Point West MC Prepared for INPEX Page A-6

45 E. Results of PERMANOVA testing for differences in the density of Halodule leaves. Significant (P(perm) < 0.05) terms in bold. Monte Carlo ( MC ) simulation was used to calculate P values where unique permutations < 100. Source df SS MS Pseudo-F P(perm) Phase 1 1.2E E Treatment 1 4.7E E Survey(Phase) 1 9.3E E Location(Treatment) 5 3.0E E PhasexTreatment 1 1.2E E Site(Location(Treatment)) E E PhasexLocation(Treatment) 5 6.5E E Survey(Phase)xTreatment 1 2.6E E PhasexSite(Location(Treatment)) E E Survey(Ph)xLocation(Tr) 4 5.7E E Survey(Ph)xSite(Lo(Tr)) E E Residual E E+05 Total E+09 Pairwise Comparison Term 'SuxLo(Tr)' for pairs of levels of factor 'Survey' Groups t P Impact Fannie Bay Lee Point Woods Inlet Contingency Casuarina East Point MC Control Charles Point East MC Charles Point West Prepared for INPEX Page A-7

46 Pairwise Comparison Term 'Su(Ph)xSi(Lo(Tr))' for pairs of levels of factor 'Survey' Groups t P Impact Fanny Bay FB_N FB_M FB_S Lee Point LP_E NA NA LP_M NA NA LP_W2 NA NA Woods Inlet WI_E WI_S WI_W MC Contingency Casuarina CAS_ CAS_ CAS_ CAS_M CAS_S East Point EP_ MC EP_2 Denominator is 0 EP_ MC Control Charles Point East CPE_ CPE_ CPE_ Charles Point West CPW_ CPW_ CPW_ Prepared for INPEX Page A-8

47 F. Results of PERMANOVA testing for differences in the density of seagrass leaves. Significant (P(perm) < 0.05) terms in bold. Monte Carlo ( MC ) simulation was used to calculate P values where unique permutations < 100. Source df SS MS Pseudo-F P(perm) Phase 1 1.7E E Treatment 1 1.4E E Survey(Phase) 1 1.7E E Location(Treatment) 5 3.6E E PhasexTreatment 1 5.9E E Site(Location(Treatment)) E E PhasexLocation(Treatment) 5 1.7E E Survey(Phase)xTreatment 1 7.2E E PhasexSite(Location(Treatment)) E E Survey(Phase)xLocation(Treatment) E E Survey(Phase)xSite(Location(Treatment)) E E Residual E E+05 Total E+09 Pairwise Comparison Term 'SuxLo(Tr)' for pairs of levels of factor 'Survey' (DC01 Vs DC02) Groups t P Impact Fannie Bay Lee Point Woods Inlet Contingency Casuarina East Point Control Charles Point East MC Charles Point West Prepared for INPEX Page A-9

48 Pairwise Comparison Term 'Su(Ph)xSi(Lo(Tr))' for pairs of levels of factor 'Survey' (DC01 Vs DC02) Groups t P Impact Fanny Bay FB_N FB_M FB_S Lee Point LP_E LP_M LP_W2 Woods Inlet WI_E WI_S WI_W MC Contingency Casuarina CAS_ CAS_ CAS_ CAS_M CAS_S East Point EP_ EP_ EP_ Control Charles Point East CPE_ CPE_ CPE_ Charles Point West CPW_ CPW_ CPW_ Prepared for INPEX Page A-10

49 G. Results of PERMANOVA testing for differences in seagrass percent patchiness. Significant (P(perm) < 0.05) terms in bold. Monte Carlo ( MC ) simulation was used to calculate P values where unique permutations < 100. Source df SS MS Pseudo-F P(perm) Phase Treatment Survey(Phase) Location(Treatment) PhasexTreatment PhasexLocation(Treatment) Survey(Phase)xTreatment Survey(Phase)xLocation(Treatment) Residual Total Prepared for INPEX Page A-11

50 H. Results of PERMANOVA testing for differences in the epiphytes percent cover of seagrass leaves. Significant (P(perm) < 0.05) terms in bold. Monte Carlo ( MC ) simulation was used to calculate P values where unique permutations < 100. Epiphytes Source df SS MS Pseudo-F P(perm) Phase 1 6.3E E Treatment 1 6.3E E Survey(Phase) 1 1.2E E Location(Treatment) 5 2.0E E PhasexTreatment 1 6.3E E Site(Location(Treatment)) E E PhasexLocation(Treatment) 5 2.0E E Survey(Phase)xTreatment 1 1.2E E PhasexSite(Location(Treatment)) E E Survey(Phase)xLocation(Treatment) 5 5.5E E Survey(Phase)xSite(Location(Treatment)) E E Residual E E+16 Total E+19 Pairwise Comparisons for Seagrass Epiphytes Cover Term 'Su(Ph)xSi(Lo(Tr))' for pairs of levels of factor 'Survey' (DC01 Vs DC02) Groups t P Impact Fanny Bay FB_N FB_M FB_S MC Lee Point LP_E LP_M MC LP_W MC Woods Inlet WI_E MC WI_S MC WI_W Control Casuarina CAS_ MC CAS_ MC CAS_ MC CAS_M MC CAS_S MC East Point EP_ MC EP_ EP_ Charles Point East CPE_ MC CPE_ MC CPE_ Charles Point West CPW_ MC CPW_ MC CPW_ MC Prepared for INPEX Page A-12

51 I. Results of PERMANOVA testing for differences in the sediment percent cover of seagrass leaves. Significant (P(perm) < 0.05) terms in bold. Monte Carlo ( MC ) simulation was used to calculate P values where unique permutations < 100. Sediment Source df SS MS Pseudo-F P(perm) Phase 1 5.3E E Treatment 1 2.7E E Survey(Phase) 1 2.6E E Location(Treatment) 5 2.0E E PhasexTreatment 1 1.4E E Site(Location(Treatment)) E E PhasexLocation(Treatment) 5 1.6E E Survey(Phase)xTreatment 1 1.7E E PhasexSite(Location(Treatment)) E E Survey(Phase)xLocation(Treatment) 5 5.5E E Survey(Phase)xSite(Location(Treatment)) E E Residual E E+02 Total E+06 Pairwise Comparisons for Sediment Cover Term 'Su(Ph)xSi(Lo(Tr))' for pairs of levels of factor 'Survey' (DC01 Vs DC02) Groups t P Impact Fanny Bay FB_N FB_M FB_S MC Lee Point LP_E MC LP_M MC LP_W2 Denominator is 0 Woods Inlet WI_E WI_S MC WI_W Denominator is 0 Control Casuarina CAS_ MC CAS_ MC CAS_ MC CAS_M MC CAS_S MC East Point EP_1 NA NA EP_ MC EP_ Charles Point East CPE_ MC CPE_ MC CPE_ Charles Point West CPW_1 CPW_ MC CPW_3 Prepared for INPEX Page A-13

52 Pairwise Comparisons for Seagrass Epiphytes Cover Term 'PhxSi(Lo(Tr))' for pairs of levels of factor 'Phase' (Before Vs During) Groups t P Impact Fanny Bay FB_N MC FB_M MC FB_S MC Lee Point LP_E MC LP_M MC LP_W MC Woods Inlet WI_E MC WI_S MC WI_W MC Control Casuarina CAS_ MC CAS_ MC CAS_ MC CAS_M MC CAS_S MC East Point EP_ MC EP_ MC EP_ MC Charles Point East CPE_ MC CPE_ MC CPE_ MC Charles Point West CPW_ MC CPW_ MC CPW_ MC Prepared for INPEX Page A-14

53 Ichthys Nearshore Environmental Monitoring Program Bimonthly Seagrass Monitoring Report - Dredging Report 2 APPENDIX B QA/QC RESULTS Prepared for INPEX Page A-15

54 Appendix-B. Results of QA/QC analyses for seagrass cover. - = No seagrass present in the quadrat. Site Quadrat no. Scorer's error Average scorer's error Comments CPE_1 CPE_2 CPE_3 CPW_1 CPW_2 CPW_3 WI_E WI_S WI_W FB_M FB_N FB_S S032_DC02_CPE_1_Q110 S032_DC02_CPE_2_Q124 S032_DC02_CPE_3_Q110 S032_DC02_CPW_1_Q129 S032_DC02_CPW_2_Q115 S032_DC02_CPW_3_Q108 S032_DC02_WI_E_Q110 S032_DC02_WI_S_Q123 S032_DC02_WI_W_Q110 S032_DC02_FB_M_Q108 S032_DC02_FB_N_Q125 S032_DC02_FB_S_Q123 2% 2% 7% 7% 7% 0% 2% 2% 7% CPE_1 CPE_2 CPE_3 CPW_1 CPW_2 CPW_3 WI_E WI_S WI_W FB_M FB_N FB_S S032_DC02_CPE_1_Q140 S032_DC02_CPE_2_Q130 S032_DC02_CPE_3_Q133 S032_DC02_CPW_1_Q134 S032_DC02_CPW_2_Q130 S032_DC02_CPW_3_Q108 S032_DC02_WI_E_Q118 S032_DC02_WI_S_Q133 S032_DC02_WI_W_Q139 S032_DC02_FB_M_Q137 S032_DC02_FB_N_Q134 S032_DC02_FB_S_Q216 2% 3% 0% 3% 3% 0% 2% 2% 2% 2% 5% 2% 3% 1% 5% 5% 7% 0% 1% 2% 2% 2% 6% EP_1 S032_DC02_EP_1A_Q106 EP_1 S032_DC02_EP_1A_Q108 EP_2 EP_3 S032_DC02_EP_2A_Q121 S032_DC02_EP_3A_Q116 8% 2% EP_2 EP_3 S032_DC02_EP_2A_Q123 S032_DC02_EP_3A_Q118 5% 2% 7% 2% CAS_M S032_DC02_CAS_M_Q108 CAS_M S032_DC02_CAS_M_Q115 CAS_S CAS_4 CAS_5 CAS_6 LP_E LP_M LP_W2 S032_DC02_CAS_S_Q123 S032_DC02_CAS_4_Q119 S032_DC02_CAS_5_Q104 S032_DC02_CAS_6_Q112 S032_DC02_LP_E_Q105 S032_DC02_LP_M_Q108 S032_DC02_LP_W2_Q115 3% 3% 0% 3% 5% 5% CAS_S CAS_4 CAS_5 CAS_6 LP_E LP_M LP_W2 S032_DC02_CAS_S_Q137 S032_DC02_CAS_4_Q133 S032_DC02_CAS_5_Q118 S032_DC02_CAS_6_Q116 S032_DC02_LP_E_Q106 S032_DC02_LP_M_Q135 S032_DC02_LP_W2_Q117 2% 2% 5% 0% 3% 0% 0% 2% 3% 4% 0% 3% 3% 3% Prepared for INPEX Page B-1

55 Ichthys Nearshore Environmental Monitoring Program Bimonthly Seagrass Monitoring Report - Dredging Report 2 APPENDIX C WATER QUALITY SUMMARY DATA Prepared for INPEX Page B-2

56 Appendix C-1. Summary of turbidity and water temperature (mean; min; maximum and percentile of occurrence) at Fannie Bay, Casuarina, Lee Point, Charles Point, Woods Inlet and East point monitoring stations from 9 November - 9 December. *= Indicates sampling periods did not cover the entire survey period. Site Name Sampling Dates Turbidity (NTU) Mean Min 5% 10% 20% 50% 80% 90% 95% Max From To Fannie Bay /11/2012 9/12/2012 Fannie Bay /11/2012 9/12/2012 Casuarina /11/2012 9/12/2012 Lee Point /11/2012 9/12/2012 Lee Point /11/2012 9/12/2012 Charles Point /11/2012 9/12/2012 Charles Point /11/2012 9/12/2012 Woods Inlet 01* /11/2012 6/12/2012 Woods Inlet 02* /11/ /11/2012 East Point /11/2012 9/12/2012 Water Temp. ( 0 C) Mean Min 5% 10% 20% 50% 80% 90% 95% Max From To Fannie Bay /11/2012 9/12/2012 Fannie Bay /11/2012 9/12/2012 Casuarina /11/2012 9/12/2012 Lee Point /11/2012 9/12/2012 Lee Point /11/2012 9/12/2012 Charles Point /11/2012 9/12/2012 Charles Point /11/2012 9/12/2012 Woods Inlet 01* /11/2012 6/12/2012 Woods Inlet 02* /11/ /11/2012 East Point /11/2012 9/12/2012 Prepared for INPEX Page C-1

57 Appendix C-2. Daily mean (±SE) water temperature from the two Fannie Bay water quality sites between 9/11/12 and 9/12/12. Extract from Cardno Water Quality database Prepared for INPEX Page C-2

58 Appendix C-3. Daily mean (±SE) water turbidity from the two Fannie Bay water quality sites between 9/11/12 and 9/12/12. Extract from Cardno Water Quality database Prepared for INPEX Page C-3

59 Appendix C-4. Daily mean (±SE) water temperature from the Casuarina Beach water quality site between 9/11/12 and 09/12/12. Extract from Cardno Water Quality database Prepared for INPEX Page C-4

60 Appendix C-5. Daily mean (±SE) water turbidity from the Casuarina Beach water quality site between 9/11/12 and 9/12/12. Extract from Cardno Water Quality database 2012 Prepared for INPEX Page C-5

61 Appendix C-6. Daily mean (±SE) water temperature from the two Lee Point water quality sites between 9/11/12 and 9/12/12. Extract from Cardno Water Quality database Prepared for INPEX Page C-6

62 Appendix C-7. Daily mean (±SE) water turbidity from the two Lee Point water quality sites between 9/11/12 and 9/12/12. Extract from Cardno Water Quality database Prepared for INPEX Page C-7

63 Appendix C-8. Daily mean (±SE) water temperature from the two Charles Point water quality sites between 9/11/12 and 9/12/12. Extract from Cardno Water Quality database Prepared for INPEX Page C-8

64 Appendix C-9. Daily mean (±SE) water turbidity from the two Charles Point water quality sites between 9/11/12 and 9/12/12. Extract from Cardno Water Quality database Prepared for INPEX Page C-9

65 Appendix C-10. Daily mean (±SE) water temperature from the two Woods Inlet water quality sites between 9/11/12 and 6/12/12 (Woods Inlet 01) and 9/11/12 to 21/11/12 (Woods Inlet 2). Extract from Cardno Water Quality database Prepared for INPEX Page C-10