Western Basin Dredging and Disposal Project Environmental ...

data not availablekWestern Basin Dredging and Disposal ProjectEnvironmental Impacts BriefingUpdated: 11 March 2013

Western Basin Dredging and Disposal Project - Environmental Impacts BriefingTable of ContentsExecutive Summary .................................................................................................. 31. Current State of Dredging Project ........................................................................ 42. Water Quality Monitoring ...................................................................................... 63. Turbidity Data and Graphs ..................................................................................... 94. Metals Testing in Gladstone Harbour ................................................................ 175. Health of Marine Life in Gladstone harbour ..................................................... 246. Seagrass data and graphs ..................................................................................... 26Map of Monitoring Sites ........................................................................................ 30#685202Page | 2

Western Basin Dredging and Disposal Project - Environmental Impacts BriefingExecutive SummaryDredging started on 20 May 2011 with one backhoe dredge – Big Boss, which concluded itsoperations in April 2012. The Razende Bol backhoe dredge commenced on 10 June 2011 andcompleted works in August 2012. A third small grab dredge – Tarvos - commenced operationin August 2011 and concluded its operations in February 2012. The cutter suction dredge AlMahaar commenced operations on 5 September 2011 and is still on the project. A fourthdredge, the backhoe Simson began work on 5 October 2011, broke down on Christmas dayand did not resume operations. It left the project in April 2012. The Hippopotes a backhoedredge began work on the project in April 2012 and completed works and left the project inJuly 2012. The cutter suction dredge Castor began works in June 2012 and continues to workon the project periodically. The Rotterdam, a trailing suction hopper dredge commencedwork on the project on 21 October 2012.At present (11/03/13) there are three dredges operating on the project – the Al Mahaar,the Rotterdam and the Castor. However, the Al Mahaar is currently under maintenance.To date (as at 11 March 2013) an estimated 14,110,000m 3 of dredging has occurred. To putthis in perspective 22,000,000m 3 of dredging took place in Gladstone between 1980 and1982.Gladstone Ports Corporation (GPC) is committed to ensuring the WBDDP is conducted withinthe strict conditioning guidelines set by the project approval conditions to ensure theminimum impact on the marine life in Gladstone harbour.The extensive independent environmental water quality monitoring program for the WesternBasin Dredging and Disposal Project (WBDDP) shows no visible or scientific signs of anynegative impact from changes in water quality to date. The Water Quality MonitoringProgram is overseen by the Dredge Technical Reference Panel appointed by the FederalMinister for Sustainability, Environment, Population and Water.The Department of Environment and Heritage Protection (EHP) have conducted elevenreviews of water quality in the Gladstone harbour to date. A summary of final resultsreleased in January 2013 concluded that the results DO NOT suggest that water quality inGladstone harbour and related waterways present a threat to fish and/or human health. TheEHP also concluded that there is no evidence that dredging increases dissolved metalconcentrations or leads to acidic conditions.CSIRO released a report in May 2012 on the results of sampling metal concentrations in theGladstone harbor. The team of CSIRO scientists reported they found no evidence of increaseddissolved metal concentrations in the areas of Port Curtis that are being dredged and totalmetal concentrations in the seafloor sediment samples were below ANZECC guideline valuesfor all metals.Scientific tests are currently being conducted to determine the affects of the recent floods(Jan 13) on the ecosystem in the Gladstone harbour.#685202Page | 3

Western Basin Dredging and Disposal Project - Environmental Impacts Briefing1. Dredging Project Scope and ProgressDredging‣ As at 11 March 2013, 14,110,000m 3 of dredging has occurred.‣ Dredging started on 20 May 2011 with one backhoe dredge – Big Boss, which concludedits operations in April 2012.‣ The Razende Bol backhoe dredge commenced on 10 June 2011 and finished on theproject in August 2012.‣ A third small grab dredge – Tarvos - commenced operation in August 2011 andconcluded its operations in February 2012.‣ The cutter suction dredge Al Mahaar commenced operations on 5 September 2011 andis still on the project.‣ The backhoe Simson began work on 5 October 2011, broke down on Christmas day anddid not resume operations. It left the project in April 2012.‣ The Hippopotes a medium size backhoe dredge began work on the project in April 2012and completed works and left the project in July 2012.‣ The cutter suction dredge Castor commenced operations on 25 June 2012 and worksperiodically on the project.‣ The Rotterdam, a trailing suction hopper dredge commenced operations on Monday 22October 2012.‣ At present (11 March 2013) there are three dredges working on the project. The AlMahaar and Castor, both cutter suction dredges and the Rotterdam, a trailing suctionhopper dredge. However, the Al Mahaar is currently under maintenance.Disposal‣ An 8.8km perimeter, called the bund wall was completed in October 2011 and sincethen approximately 9.7 million cubic metres of dredge material has been stored insidethe reclamation area at Fisherman’s Landing.‣ Sealing of the bund wall is complete. Material is placed against the wall in significantvolumes, blocking the passage of water into and out of the porous wall. The reclamationarea has been divided into north and south sections by an internal mound of dredgematerial.‣ A Transitional Environmental Program (TEP) was approved on 25th June 2012 byDepartment of Environment and Heritage Protection (EHP) to allow for the bund sealingworks to be undertaken in a shortened period. The TEP was completed and deemed asuccess on August 4; two days ahead of schedule.‣ Approximately 4.4 million cubic metres have been disposed at the East Banks offshoredisposal site.‣ The offshore site was selected using a number of criteria in consultation withenvironmental experts and harbour users, such as commercial fishermen andrecreational boat users.‣ The East Banks site, like all project activities and operations is located outside the GreatBarrier Reef Marine Park.#685202Page | 4

Western Basin Dredging and Disposal Project - Environmental Impacts BriefingPrevious Dredging Events in Gladstone HarbourAs shown below, there has been significant dredging activity in Gladstone harbour since 1960.Capital dredging projectsDate Location Depth Volume Dredge type Disposal site1960-66 Auckland Point berths,Barney Point berths andharbour channelAuckland Point - 23ftBarney Point - 39ftHarbour channel -9.6mA significantvolume1968 Entrance channel 10.4m Furtherdeepening1980-82 Approach channels toClinton and Fisherman’sLanding, as well as theMarina20 mill m 3 Trailer /Cutter1986-87 Inner harbour channelswidened and berthsdeepenedAuckland channelwidened to 180m anddeepened to 15m3 mill m 3 Trailer /Cuttersea / ashoreashore1987 Outer channel 15.8m 2.5 mill m 3 Trailer /seaCutter1997 Fisherman’s Landing 1 mill m 31997 Outer channel 16.3m 1 mill m 3 Trailer sea1998 Inner channel swing basin 2 mill m 31999 Inner channel 2 mill m 3 Trailer / ashoreCutter2001-03 Berth 3 at RG Tanna Coal2 mill m 3 Trailer / ashoreTerminal and Fisherman’sLanding includingdeepening of TarginnieChannel and Clinton BypassChannelCutter2005 RG Tanna Coal Terminal0.75 mill m 3 Cutter ashoreberth 42008-09 Fisherman’s Landing berth0.66 mill m 3 Cutter ashorepocket and approach2009-10 Gladstone Marina 350,000 m 3 Trailer /Cutterashore2010-2011Oct-JanEarly works access to CurtisIsland3 Cutter ashore475,000 mMaintenance DredgingSince 1996 maintenance dredging of around 100,000m 3 has occurred every year.Maintenance dredging material has been disposed at the East Banks offshore site. The TrailerHopper Suction Dredge Brisbane calls into Gladstone to carry out maintenance dredging eachyear to maintain the depth of the existing channels and shipping berths at each of the 6wharves in Gladstone harbour.#685202Page | 5

Western Basin Dredging and Disposal Project - Environmental Impacts Briefing2. Water Quality MonitoringHistorical InformationSince 1994, over $25 million of water quality monitoring, benthic life testing and seagrassmonitoring has been undertaken.WBDDP Water Quality MonitoringThe project conditioning requires a comprehensive water quality monitoring programinvolving 16 continuous monitoring sites with 16 additional manual monitors testing watersamples to provide actual readings close to the dredges, as well as background readingsthroughout Gladstone harbour.See attached map at the end of this briefing document.Water quality monitoring in the harbour is required by State and Federal regulators for GPC’sWestern Basin Dredging & Disposal Program (WBDDP). The monitoring is conducted byVision Environment QLD, a local company employing approximately 20 people.There are 2 methods of data collection: telemetry and manual. The telemetry system is atechnology allowing remote measurement and conveyance of information at 15 minute#685202Page | 6

Western Basin Dredging and Disposal Project - Environmental Impacts Briefingintervals from buoys at several sites throughout the harbour. Data is collected on dual sondesand the mean is the average of the two sondes. The telemetry method is used to allowinstant, regular and reliable data collection. The other method is manual by VisionEnvironment QLD staff in boats collecting water samples.Once collected, the data is sent to GPC’s LNG project team daily and uploaded into the datastorage and graphing system EnviroSys. Thousands of records of data have been collectedsince monitoring started in February 2010.The data is routinely provided to EHP as part of GPC’s license conditions.Water quality is measured at a number of different sites for a wide range of parametersincluding:• Turbidity every 15 minutes• Dissolved oxygen every 15 minutes• pH every 15 minutes• Salinity / Conductivity every 15 minutes• Temperature every 15 minutes• Light (PAR) every 15 minutes• Nutrients every quarter• Chlorophyll A every quarter• Metals every month, or more often as requiredResults• The waters of Gladstone harbour are naturally turbid as it is sheltered from the openocean by several islands. Tidal activity alone frequently causes turbidity levels whichexceed the Queensland Water Quality Guidelines (QWQG);• Results have consistently shown turbidity levels and total suspended solids are primarilyimpacted by tidal activity;• There is clear seasonal variability in turbidity levels, higher in the summer wet seasonand lower in winter. Results show a consistent reduction in recorded turbidity levelsduring the dry season months and a steady increase following rain and flood events;• Water clarity is generally lower in The Narrows and around the mouth of Graham’sCreek and higher toward the outer harbour;• Dissolved oxygen (DO) and pH show similar trends with lower values in The Narrowsand Grahams Creek areas and higher values in the outer harbour;• DO levels fluctuate with tidal and diurnal (daily) cycles;• DO concentrations generally fall within the Australia Water Quality Guidelines (AWQG)recommended range of 80-120% saturation;• DO levels decrease after rainfall events; big rain events typical of the wet season areshown in the DO data;#685202Page | 7

Western Basin Dredging and Disposal Project - Environmental Impacts Briefing• There is clear seasonal variability water temperature decreases and increases at allmonitored sites from the wet season into the dry season (on average a 5 o change intemperature is recorded); and• Conductivity results have remained lower than typical marine/estuarine conditions.Dredging activities undertaken to date appear to have had very little impact on the longertermwater quality in Gladstone harbour.#685202Page | 8

Western Basin Dredging and Disposal Project - Environmental Impacts Briefing3. Turbidity Data and GraphsTurbidity Data for the period: 8 February to 8 March 2013Turbidity data is presented in the graph as the Exponentially Weighted Moving Average(EWMA). The 99 th percentile turbidity trigger varies in the wet and dry seasons at each of thesites and is set by the regulators, based on historic turbidity data.The 6 sites shown correspond to the following areas of Gladstone Port Curtis:QE4ST1BG10P2BSGM1SGM2Inner harbour, north of Fisherman’s Landing expansion areaInner harbour, south east of Fisherman’s Landing expansion areaInner harbour, south of Curtis IslandInner harbour, adjacent to Wiggins Island and Calliope River estuaryOuter harbour, north of East Banks offshore disposal areaOuter harbour, north of East Banks offshore disposal areaAs the graphs below demonstrate turbidity levels increased significantly due to the recentfloods (Jan 13), but has decreased overall since the wet season began. Turbidity levels in theharbor rose at some sites which was primarily due to elevated winds and large tidal rangesassociated with the tide cycle. But overall turbidity levels have been decreasing and haveremained under the trigger levels.Under normal circumstances turbidity at the inshore compliance sites (QE4, ST1, P2B andBG10) is generally influenced by the tidal regime, and this was again evident during February2013.At the offshore compliance sites (SGM1 and SGM2) turbidity levels are primarily related towind speeds, or more precisely, wave action generated by wind speeds.#685202Page | 9

Western Basin Dredging and Disposal Project - Environmental Impacts BriefingInner harbour turbidity monitoring sites#685202Page | 10

Western Basin Dredging and Disposal Project - Environmental Impacts BriefingOuter harbour turbidity monitoring sites#685202Page | 11

Western Basin Dredging and Disposal Project - Environmental Impacts BriefingSalinityThe typical salinity range in the south eastern region of the coral sea is 35 to 37. During theJan/Feb 2013 flood event in Gladstone a very large quantity of freshwater was discharged intothe Western Basin. This resulted in a rapid and sustained decline in salinity, and for severaldays salinity was reduced to levels similar to freshwater. Since this time, the tidal flows havereintroduced seawater into the harbour and salinity is slowly move back towards the typicalseawater range. This process is likely to take several months.The Salinity data is raw and has not been processed in any way. The intermittent recording of“0” and step changes are not likely to be representative of ambient conditions. These aremost likely to be associated with equipment malfunction.pH and TemperatureAs observed in previous months, pH exhibited a clear geographical gradient of increasingvalues from the inner harbour (7.8 in the Narrows) to the outer harbour and offshore (8.2).Rodds Bay pH (8.0) was similar to that recorded at Western Basin sites. All values were withinthe QWQG recommended range (7.0 to 8.4 inshore, 8.1 to 8.4 offshore).The pH was also highly impacted by the rain event, with the majority of inshore sitesexhibiting a marked decrease. While pH at compliance sites remained with QWQG (7.0 to 8.4)at all times, sites within the upper Narrows exhibited acidic conditions. Site QE8 in the upperNarrows exhibited pH as low as 6.0 for short periods of time, with pH remaining below 7.0 for#685202Page | 12

Western Basin Dredging and Disposal Project - Environmental Impacts Briefingapproximately four days. At QE6 further down the Narrows, pH levels as low as 6.3 wererecorded, with pH below 7.0 recorded for three days. At sites QE3 and QE2‐1, pH of around7.0 was recorded for short periods of time. Compliance site QE4 recorded pH of 7.1, while ST1and P2B recorded values of 7.3 and BG10 recorded pH as low as 7.5.Offshore and outer harbour sites exhibited little change in pH at this time. Although anincreasing gradient for pH from the Narrows to the outer harbour has been a consistentfinding during the monitoring program, the rate of increase was much greater than previouslyrecorded. This spatial pattern of pH suggests acidic inputs from the north through theNarrows, possibly from the Fitzroy River, with impacts felt within Port Curtis as far as theWestern Basin. Acidic inputs most likely from acid sulphate soils, or the breakdown of organicmatter resulting in a reducing environment (lower oxygen and higher acidity) followingextreme rain events have beenknown to contribute to fish kills, although none were formallyreported within the Western Basin area.Nonetheless mean Wet Season 4 pH remained similar to previous, ranging from 7.9 at QE4,ST1 and P2B to 8.1 at SGM2. For the month of January, mean temperatures at inshore sites(27.8 to 28.5 °C) were higher than those at offshore sites (27.5 to 27.8 °C), with temperaturesat Rodds Bay (27.8 to 28.0 °C) similar to Port Curtis inshore sites. Conductivity at inshore sites(53.2 to 56.2 mS/cm) was similar to offshore (52.2 to 53.3 mS/cm) and Rodds Bay sites (54.0to 55.3 mS/cm).#685202Page | 13

Western Basin Dredging and Disposal Project - Environmental Impacts BriefingConductivity and Dissolved OxygenConductivity was highly influenced by the rain event, with values less than 5 mS/cm(technically considered freshwater), recorded at all inshore sites. Conductivity of 0 mS/cmwas recorded at sites P2B and ST1 for short periods of time. Even outer harbour sitesrecorded conductivity values below 20 mS/cm for a short period of time, while offshore sitesexhibited conductivity less than 40 mS/cm, indicating the spatial extent of the freshwaterrunoff. However, these values had only a minimal effect on the mean Wet Season 4conductivity values at compliance sites, which ranged from 51.6 mS/cm at QE4 to 53.0 mS/cmat SGM2.Dissolved oxygen concentrations at all inshore sites exhibited a decrease of up to 30% inresponse to the rain event. Concentrations decreased to between 70 to 80% saturation fromthe typical background concentrations of between 90 and 100% saturation. Decreases wereless evident at the outer harbour and offshore sites. A geographic trend was also evident fordissolved oxygen, with sites located within the Narrows exhibiting lower dissolved oxygenthan outer harbour sites. One of the most visible effects of critically low dissolved oxygenconcentrations is aquatic death (DERM, 2009), which can include fish kills (ERISS, 2001). TheQWQG (DERM, 2009) note that values as low as 40% may occur in estuaries for short periodsfollowing material inflow events after rainfall, but that values less than 30% saturation aretoxic to some fish species.This suggests that dissolved oxygen concentrations in the harbour as recorded by thecontinuous loggers, although breaching the QWQG, were likely to still be sufficient to supportaquatic life. The short lived declines had little impact on the mean Wet Season 4 dissolvedoxygen values at compliance sites which ranged from 94% saturation at QE4 to 100%saturation at SGM2.#685202Page | 14

Western Basin Dredging and Disposal Project - Environmental Impacts BriefingNutrients and OrganicsNutrient samples were collected at offshore (14th January), inshore (15th January) and RoddsBay (16th January) sites, prior to the extreme weather conditions of late January 2013.Overall, concentrations of chlorophyll a, total phosphorus, orthophosphate, ammonia andnitrate during January were similar to Wet Season 4 to date concentrations, indicating thatconcentrations during January were typical for current wet season conditions. However, totalnitrogen, TKN and nitrite concentrations were higher during January than the mean WetSeason 4 concentrations, indicating an increase in these nutrients was evident during January.Increases in total nitrogen were evident in all zones except offshore however the TKN resultsindicate that the nitrogen was primarily in an organic form, and thus not readily bioavailable.The VEQ control data indicated that detectable levels of total phosphorus were found in thelab andfield blanks on the 16th January, indicating minor contamination of the VEQ MilliQwater. This hassince been addressed with flushing and cleansing of the water system. Totalphosphorus results forthat day (Rodds Bay) were all found to be below laboratory limits ofdetection, and thus were notimpacted by the potential contamination.Nitrite (precursor to the bioavailable ammonia) increases were evident within the Narrowsand Western Basin. Higher concentrations of nitrogen forms can normally be linked toincreases in rainfall and freshwater influx to the system. However, as rainfall remained low inthe months prior to the January nutrient sampling, the increases may be a result of higherdecomposition rates due to higher temperatures.#685202Page | 15

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Western Basin Dredging and Disposal Project - Environmental Impacts Briefing4. Metals Testing in Gladstone HarbourThere are three ways that metals present themselves in a water environment. They canappear in sediment on the sea floor, as total metals or as dissolved metals.This is a summary of the metals testing data collected in January 2012 as part of the dredgingproject.Metals in sediments – total metalsMetals in sediments were tested in 2004, 2006, 2009 and are scheduled again later this year.Additionally over 1000 drill holes and multiple samples were taken for the pre dredgingassessment in the last 4 years.More frequent testing has not been required as all these studies found acceptable and evenlow levels of metals. So far all the metals levels in water have been acceptable.Total metals in waterTotal metals have been measured since 2008 and more extensively under this project sinceOctober 2010. All results to date have shown acceptable levels of total metals within theANZECC (Australian and New Zealand Environment Conservation Council) guidelines for waterquality.Dissolved metals in waterDissolved metals are measured monthly since October 2011. Results to date have showndissolved metals are turning up in very low levels, and therefore are not of environmentalconcern. The highest levels of all metals were recorded during the January 2011 floods.Latest ResultsTotal and dissolved metal samples were collected at Rodds Bay (4th January), inshore (8thJanuary) and offshore (9th January) sites, prior to the extreme weather conditions of lateJanuary 2013.Overall, total metals were generally higher than dissolved metals, with concentrations loweroffshore and at Rodds Bay than inshore Port Curtis. In contrast to previous months whereconcentrations of most metals were more elevated in the Western Basin and Narrows, duringJanuary most total metals were highest in the Mid and Outer Harbour zone. This was mostlyattributed to the high concentrations recorded at site BG10, which were up to ‐ four foldhigher than concentrations recorded at other sites within this zone (P5 and B7).However, it must be noted that concentrations at P5 and B7 during January also appeared tobe higher than what has been recorded previously (December 2012 and prior). A trend forincreasing metals in this zone has occurred since December. The latest QueenslandDepartment of Environment and Heritage Protection (EHP) report (January 2013) states#685202Page | 17

Western Basin Dredging and Disposal Project - Environmental Impacts Briefingmonitoring of the Gladstone harbour has shown that the dredging is not a major source ofdissolved metal concentrations and there is no evidence that dredging increases dissolvedmetal concentrations or leads to acidic conditions.#685202Page | 18

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Western Basin Dredging and Disposal Project - Environmental Impacts BriefingCSIRO report on metals concentrations – May 2012Samples were taken at 21 different sites around Gladstone harbour, while dredging wastaking place. CSIRO then used very sensitive monitoring and analysis techniques to determinethe actual concentrations of metals present dissolved in water and sediment and comparedthese to samples taken between 1998-2004.CSIRO reported:• No evidence of increased dissolved metal concentrations in the areas of Port Curtis thatare being dredged.• Few identifiable trends in concentrations across the harbour. No hot spots of high metalconcentrations were found close to dredging.• Concentrations of dissolved arsenic, cadmium, cobalt, chromium, copper, manganese,nickel, lead and zinc were below the ANZECC/ARMCANZ marine water quality guidelinetrigger values that apply in Australia at all 21 sites• Concentrations of all metals were relatively low compared to other industrialisedharbours.• Dissolved aluminium concentrations were above the ANZECC/ARMCANZ (2000)environmental concern level (ECL) of 0.5 µg/L at the majority of sites sampled. It shouldbe noted the ECL value is a highly conservative value based on very limited toxicity dataand it was not possible to attribute a specific source of the dissolved aluminium.• Dissolved copper and nickel concentrations were higher in December 2011 compared toprevious CSIRO surveys between 1998 and 2004.• Total metal concentrations in the seafloor sediment samples were below ANZECCguideline values for all metals (where guidelines apply) apart from arsenic.#685202Page | 23

Western Basin Dredging and Disposal Project - Environmental Impacts Briefing5. Health of Marine Life in Gladstone HarbourDredging Technical Reference Panel (DTRP)The Dredge Technical Reference Panel (DTRP) is a committee required as part of theapprovals for the dredging project. The panel provides high-level advice to ensure dredgingmeets all of the required water quality and seagrass approval conditions to minimise impactsthe project may have on the environment.The DTRP routinely reviews seagrass health, water quality monitoring data and dredgingpractices. The panel provides advice and (if deemed necessary) makes recommendations forchanges to water quality monitoring practices or the dredging management plan togovernment regulators. The DTRP has had no cause to implement any changes to date.The panel comprises several independent scientists and representatives from governmentagencies, dredge contractors and GPC. The DTRP is required to meet regularly for the life ofthe project.GPC values the DTRP as an important part of our commitment to improving and responding totechnical issues on the Western Basin Dredging and Disposal Project.Environmental MonitoringBesides during the flood in January 2013 where high levels of turbidity was experienced in theGladstone harbour, there have been short periods of heightened turbidity levels duringextreme Spring and King tides, instigating the successful implementation of TurbidityManagement Plans.CSIRO released a report in May 2012 on their results of sampling metal concentrations inGladstone harbour. The team of CSIRO scientists reported they found no evidence ofincreased dissolved metal concentrations in the areas of Port Curtis that are being dredgedand total metal concentrations in the seafloor sediment samples were below ANZECCguideline values for all metals.A Transitional Environmental Program (TEP) was approved by regulators on 25th June 2012 toallow for the bund sealing works to be fast-tracked using two cutter suction dredges. Thisapplication was approved to reduce any long-term contribution to turbidity by the porousbund wall. The Transitional Environmental Program (TEP) was completed and deemed asuccess on August 4 2012.The Department of Environment and Heritage Protection (EHP) have conducted elevenreviews of water quality in the Gladstone harbour to date. A summary of final resultsreleased in January 2013 concluded that the results DO NOT suggest that water quality inGladstone harbour and related waterways present a threat to fish and/or human health. TheEHP also concluded that there is no evidence that dredging increases dissolved metalconcentrations or leads to acidic conditions.#685202Page | 24

Western Basin Dredging and Disposal Project - Environmental Impacts BriefingThese reports on water quality in Gladstone harbour and estuaries reported only naturalvariations and no trend in water quality deterioration caused by dredging. The focus of anumber of these reports was total and dissolved metals and sediment quality. Examinationsof raised levels of copper, aluminium and chromium concluded the samples taken confirmedthese dissolved metals are not at levels of environmental concern. EHP will continueconducting water quality testing in 2013. The reports investigate water quality changes andthe EHP will continue to monitor for any trends that may emerge.In August 2012, DAFF reported fish sampling conducted in June and July found fish health inGladstone waters is continuing to improve, even in the tougher conditions of winter. FisheriesQueensland’s latest September 2012 survey report found fish to be in overall good healthwithin Gladstone, including the harbour and spoil grounds.Scientific tests are currently being conducted to determine the affects of the recent floods(Jan 13) on the ecosystem in the Gladstone harbour.#685202Page | 25

Western Basin Dredging and Disposal Project - Environmental Impacts Briefing6. Seagrass Data and GraphsThe Department of Employment, Economic Development and Innovation (DEEDI) hasmonitored the area, biomass and species composition of seagrass in Port Curtis since 2002.As part of the WBDDP we now receive seagrass reports monthly to more closely monitor thechanges in seagrass distribution.The July 2011, DEEDI released a report on seagrass monitoring undertaken in 2011. Themajor finding was that compared to the broad distribution of meadows mapped in 2010, theseagrass beds were beginning to show signs of regrowth and recovery after the 2010/11floods.In July 2011, seagrass cover and above-ground biomass at the monitored sites had increasedsignificantly at most locations since the previous survey in April 2011. Seagrass had returnedto all sites, including new shoots of Halophila ovalis and Zostera capricorni at sites whereseagrass had previously been absent or very low in abundance along transects.Seed banks for Zostera capricorni were discovered in March 2011 at Wiggins Island andPelican Banks and for Halophila ovalis at Wiggins Island and Fisherman’s Landing. In July2011, new shoots of both species were reported across sites which had previously containedvery little aboveground biomass. This provides evidence of the start of recovery of somemeadows from seeds stored in the sediment.Lower rainfall and higher levels of light available to seagrasses were likely to have contributedto the onset of recovery since July 2011.Results of the most recent survey of seagrass condition at permanent transects on the 12thand 13th January 2013 showed that seagrasses at most locations may have reached the endof the growing season and are beginning to decline as they enter the senescent season.Seagrass percent cover at most sites had begun to decrease after reaching a seasonal peak ingrowth between November and December 2012.Dugong feeding trails at the survey site near Wiggins Island were detected in January 2012and again in February 2012. In August/September and October 2012 Dugongs were spottedin the Western Basin harbor, at QAL and in the Calliope River indicating dugongs are feedingin the Gladstone harbour.#685202Page | 26

Western Basin Dredging and Disposal Project - Environmental Impacts BriefingDeveloping a world leading rapid seagrass health assessment toolGladstone Ports Corporation has now implemented a world leading seagrass healthassessment monitoring program to protect seagrass in the Gladstone harbour. Studiesestablished initial light requirements during the growing season (1 July to 31 January) forZostera capricorni, were somewhere in the range from 4.5 to 12 mol/m2/day.Further investigations led to refining this light trigger value to 6 mol/m2/day over a rollingtwo week average, under which management actions and alerts are proposed to ensureappropriate steps are taken to mitigate seagrass declinesThis requirement of light is based on measuring the total amount of light reaching theseagrass over a 14 day average. The green dotted line shows the amount of light reaching theseabed at the benthic layer, which should remain above 6mols/day. The black triangles showthe light readings above water.The monitoring is being carried out at six sites in the harbor and is available to the public dailyon the Western Basin Dredging and Disposal Project website.#685202Page | 27

Western Basin Dredging and Disposal Project - Environmental Impacts BriefingWI5-2:14 day RA (mols/m 2 /day)PM1:14 day RA (mols/m 2 /day)TC1:14 day RA (mols/m 2 /day)7060WI5-25040302010007-Feb 14-Feb 21-Feb 28-Feb 07-Mar7060PM15040302010007-Feb 14-Feb 21-Feb 28-Feb 07-Mar7060TC15040302010007-Feb 14-Feb 21-Feb 28-Feb 07-MarAmbient PARBenthic PAR#685202Page | 28

Western Basin Dredging and Disposal Project - Environmental Impacts BriefingGC1:14 day RA (mols/m 2 /day)DC1:14 day RA (mols/m 2 /day)BS1:14 day RA (mols/m 2 /day)7060GC15040302010007-Feb 14-Feb 21-Feb 28-Feb 07-Mar7060DC15040302010007-Feb 14-Feb 21-Feb 28-Feb 07-Mar7060BS15040302010007-Feb 14-Feb 21-Feb 28-Feb 07-MarAmbient PARBenthic PARThe graphs are updated daily at www.westernbasinportdevelopment.com.au#685202Page | 29

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