Better predictions for dredge plumes

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Key experts from the public and private sectors have come together to discuss the development of the first science-based guidelines on modelling to predict and manage the environmental impacts caused by dredging in Western Australia, based on the work undertaken by the Western Australian Marine Science Institution (WAMSI) Dredging Science Node researchers.

The workshop, led by CSIRO scientists who are working on the numerical modelling project and the Dredging Science Node leaders, with leading practitioners from a number of environmental consulting companies representing the private sector, focused on the challenges and priorities of the guidelines to ensure they can be readily applied for Environmental Impact Assessment (EIA) in Western Australia.

The accuracy of dredge plume modelling results rely on the quality of input data, correct formulations of internal physics, and appropriate parameterizations of processes that are not fully simulated by the model. Currently there is large uncertainty in model input and parameterizations. Given these challenges, there is a critical need to develop detailed protocols for measurement and modelling of sediments resuspended from dredging operations to improve the impact predictions of proposed future dredging operations.

The project is focused on the transport and fate of sediments released by the dredging process and improving the predictive capacity of dredge plume models. CSIRO researcher Dr Chaojiao Sun and her team are undertaking a detailed investigation on the primary sources of uncertainty in the impact prediction modelling process. The outcomes will provide improved protocols and methods for modelling of suspended sediments and focus effort on critical aspects of the modelling process. The purpose of the workshop was to brainstorm with the EIA modelling practitioners to identify EIA modelling challenges and pathways forward.

A CTD rosette was lowered into the turbid water near Onslow where dredging was taking place at the Chevron Wheatstone site. The instruments on the rosette included CTD, Niskin Bottles, LISST-100x, SBE 19plus, Hydroscat-6, and Hydrorad2. They measured seawater properties, optical backscatter, sediment particle size distribution and volume concentration, downwelling solar signal and upwelling light signal at depths, backscatter and florescence (Image: CSIRO).

A number of challenges have been identified at the workshop such as; uncertainties around dredging program at the EIA stage, lack of information on source terms and spill rates, lack of knowledge in some critical model parameters, feasible ways in defining zones of impact, robust metrics for estimating uncertainty in model prediction, designing monitoring campaign that are useful for model validation, and making model output interpretable for ecologists at temporal and spatial scales of interest for assessing ecological impact. The experts agree that a comprehensive “parameter library” including source terms and model parameter ranges that are typical for the tropical Australian environment would be valuable for future dredge plume modelling.

When the WAMSI Dredging Science Node releases its final report for the projects in 2017, one of the outcomes will be the first set of guidelines on dredge plume modelling that can be applied not only to EIA requirements in Western Australia, but also to other tropical environments in Australia. These guidelines will include recommendations on data collection procedures for model calibration and validation, best-practice process algorithms and parameterizations, metrics for assessing robustness of the model, and linkages to ecological modelling. They will provide greater consistency in the modelling practice and communication of model uncertainty and help improve impact predictions from proposed dredging operations.

A clearly visible dredge plume around the dredges near Onslow (Image: CSIRO).

To stay informed of new publications follow the Dredging Science Node on the WAMSI website or WAMSI Dredging Science Node on Linkedin

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

 

Category:

Dredging Science

WAMSI broadens its independent capability with new R&D committee

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The Western Australian Marine Science Institution (WAMSI) has welcomed four new research and industry heavyweights to its Research and Development Committee, adding to the leadership, science, innovation and business acumen to oversee its research development performance.

Director of The University of Western Australia (UWA) Centre for Offshore Foundation Systems and 2015 WA Scientist of the Year Professor Mark Cassidy FTSE;  UWA Emeritus Professor Di Walker; Managing Director of the respected marine and coastal environmental consulting service BMT Oceanica Mark Bailey; and Principal Research Scientist at CSIRO Dr Beth Fulton join standing members, Executive Director of the Science and Conservation Division for the Department of Parks and Wildlife Dr Margaret Byrne, WAMSI Chair Naomi Brown, and independent Chair Kevin Goss, to see WAMSI’s current projects through to completion and establish its future direction.     

The four new committee members will join (L-R) WAMSI R&D Independent Chair Kevin Goss, WAMSI Chair Naomi Brown and Director Science Division, Department of Parks and Wildlife Dr Margaret Byrne (photo: Angela Rossen)

WAMSI is delivering two of the largest single-issue marine research programs in Australia. The $20 million Dredging Science Node will vastly improve the planning and regulation of major dredging operations in the marine environment around Australia.

WAMSI’s $30 million Kimberley Marine Research Program is delivering the research needed to support the management of the Kimberley region’s marine environments, particularly the proposed State Government marine parks as part of the Kimberley Science and Conservation Strategy.

“The new committee includes leading scientists with multi-disciplinary backgrounds, and experts who apply new research and information,” WAMSI CEO Patrick Seares said. “Together they provide different perspectives to enhance our research quality, which is critical for an outcomes focussed collaboration such as WAMSI.”

“These high calibre committee members are exactly the right group to ensure both excellent finalisation and knowledge transfer of our current research programs, as well as provide added value and independent oversight of the emerging research planning activities under the Blueprint for Marine Science,” Mr Seares said. 

Mr Seares thanked outgoing members: AIMS Science and Business Leader Dr Steve Rogers; CSIRO Research Leader Dr Andy Steven; and UWA Emeritus Professor Alistar Robertson for their leadership and guidance.

“Overseeing the start-up of a $50 million research agenda across 14 research organisations, and in some complex and unstudied environments, is not without its challenges,” he said. “I speak on behalf of all the WAMSI joint venture partners when I thank the past members for their efforts in establishing a high quality, and high value, science program.”

WAMSI Research and Development Committee:

  • Mr Kevin Goss: Chair (ex CEO Future Farm Industries)
  • Ms Naomi Brown: WAMSI, Chairman
  • Dr Margaret Byrne : Director Science Division, Department of Parks and Wildlife
  • Prof Mark Cassidy FTSE: Director of the Centre for Offshore Foundation Systems at UWA
  • Prof Di Walker:  Emeritus Professor, UWA
  • Mr Mark Bailey: Managing Director, BMT Oceanica
  • Dr Beth Fulton: Principal Research Scientist, CSIRO

 

Professor Mark Cassidy FTSE 

Professor Mark Cassidy is an ARC Laureate Fellow, the Lloyd’s Register Foundation Chair in Offshore Foundations, Deputy Director of the ARC Centre of Excellence for Geotechnical Science and Engineering and Director of UWA’s Centre for Offshore Foundation Systems (COFS). Mark graduated in Civil Engineering with a University medal from the University of Queensland in 1994, and as a Rhodes Scholar, attained a doctorate in Engineering Science from the University of Oxford in 1999. His research interests are in offshore geotechnics and engineering, predominantly in developing models for the analysis of oil and gas platforms, mobile drilling rigs, anchors and pipelines.

Mark is a distinguished civil engineer whose research has underpinned the safe and economic construction of oil and gas platforms in our oceans. His advice has been incorporated into the design of platform and pipeline infrastructure currently being constructed off the coast of Western Australia. As an Australian Research Council Laureate Fellow, Professor Cassidy’s research seeks solutions to unlock the vast reserves of stranded gas in our remote and deep oceans, where the geotechnical response of the seabed sediment is poorly understood. Mark has published over 190 refereed journal and conference papers and jointly holds two international patents with Singaporean mobile jack-up builders Keppel Offshore and Marine. He is a Fellow of the Australian Academy of Technological Sciences and Engineering and Engineers Australia. Mark was named Western Australian Scientist of the Year 2015.

Professor Diana Walker 

Emeritus Winthrop Professor Di Walker researches in Marine Botany at the Oceans Institute at the The University of Western Australia. Her research interests are in the ecology of seagrasses and macroalgae and she has published widely in the international literature on nutrient cycling and productivity by seagrasses and macroalgae in marine and estuarine environments.  Her work includes the impact of sewage outfalls on coral reefs in the Red Sea, nutrient cycling in system scale studies in Shark Bay and Rottnest Island, consequences of seagrass loss in Princess Royal Harbour, Albany, and studies of the roles of seagrass meadows around the WA coast. 

Di has published over a 110 refereed scientific papers and book chapters.  She has also edited or co-edited 10 books.

Mr Mark Bailey 

Mark is the Managing Director of BMT Oceanica and a Senior Principal Consultant.  Mark has substantial professional experience in engineering and environmental work. Mark commenced his career as a civil engineer in 1986 and worked in marine construction and commercial project management.  Since completing his MEngSc in environmental modelling in 1996, Mark has worked continuously in the fields of marine environmental impact assessment and environmental project management.

Mark has strategic, commercial and business management skills developed in his role as a director of Oceanica and BMT Oceanica since 2002.  Mark is a Certified Practising Engineer with the Institution of Engineers Australia and a graduate of the Australian Institute of Company Directors.

Dr Elizabeth (Beth) Fulton 

Beth Fulton obtained her BSc (with first class Honours jointly in Mathematics and Marine Biology) from James Cook University in Townsville in 1997 and her PhD on ‘The effects of the structure and formulation of ecosystem models on model performance’ at the University of Tasmania in 2000.

She joined CSIRO in 2001 as a postdoctoral Fellow, looking into robust indicators of the ecological effects of fishing. It was at this time she applied the lessons learnt in her PhD to begin the serious development of the ecosystem model Atlantis and to begin co-developing InVitro. She was appointed to CSIRO as a research scientist in 2004, eventually taking up leadership of the ecosystem modelling and development team.

The Atlantis computer model was rated the world’s best for strategic evaluation of marine fisheries management issues by the United Nations Food and Agriculture Organisation. It is used to provide strategic advice to management bodies in Australia, the United States and Europe. The InVitro computer model, which she co-developed, allows users to explore the impacts and management of the myriad pressures on marine and coastal environments. These models were the first ones in the world to give equal attention to biophysical and human components of marine ecosystems.

 

 

Confidential information unlocks secrets to coral reproduction in Western Australia

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The release of data records within confidential reports has given researchers rare access to information that is providing a new insight into the unique reproductive cycles for the remote coral reefs along Western Australia’s (WA’s) coastline.

While the rapid industrial expansion through regions of WA in the last decade has seen an increase in the number of studies of coral reproduction, access to data within confidential reports to industry and government has only now unlocked information relating to tens of thousands of corals and hundreds of species, from over a dozen reefs spanning 20 degrees of latitude.

Project leader Dr James Gilmour from the Australian Institute of Marine Science, along with CSIRO Marine and Atmospheric Researchers found that the results from the Western Australian Marine Science Institution (WAMSI) Dredging Science Node published this month in the journal Peer J carry important management implications.

“Environmental managers aim to minimise human impacts during significant periods of larval production and recruitment on reefs, but doing so requires knowledge of the modes and timing of coral reproduction,” Dr Gilmour said. “From these data we were able to identify broad latitudinal patterns, but many gaps in knowledge remain due to paucity of data, biased sampling, issues with methodology and the profound difficulty in distinguishing coral species.”

Because of WA’s phenomenal diversity of habitats and coral communities, and wide range in reef-level patterns of coral reproduction, the examination of patterns of reproduction has been divided among six regions:

  1. Kimberley Oceanic;
  2. Kimberley;
  3. Pilbara;
  4. Ningaloo;
  5. Abrolhos and Shark Bay; and
  6. Rottnest and southwest WA
Source: Gilmour J, Speed CW, Babcock R. (2016) Coral reproduction in Western Australia. PeerJ 4:e2010 doi.org/10.7717/peerj.2010

Among these regions, the diversity of coral was found to decrease with increasing latitude, with the Houtman Abrolhos Islands having the highest latitude coral reefs in Western Australia.

The study found that mass spawning during autumn occurred on all tropical and sub-tropical reefs. A smaller, multi-specific spawning during spring decreased from approximately one quarter of corals on the Kimberley Oceanic reefs to little participation at Ningaloo.

Within these seasons, spawning was concentrated in March and/or April, and October and/or November, depending on the timing of the full moon. The timing of the full moon was critical to determining the month of spawning within these seasons, and whether spawning was ‘split’ over two consecutive months.

Mixed coral assemblage of spawning and brooding corals (Image: James Gilmour)

Most studies were found to have focused on species of Acropora, which include some of the major corals responsible for building the complexity that supports reef diversity. However, other reefs are dominated by non-Acropora corals, for which far less is known about their reproduction.

Studies conducted by industry and consultants in the Dampier Archipelago highlight the different patterns of reproduction among reefs in WA, according to their contrasting species abundances. For example, functionally important species of massive Porites seemed to spawn through spring to autumn on Kimberley Oceanic reefs and during summer in the Pilbara region.

“Most studies of coral reproduction in WA have been conducted over a few months at several reefs, of which there are few published accounts, leaving large gaps in knowledge,” Dr Gilmour said. “The gaps are significant because the existing data illustrate just how unique the patterns of reproduction displayed by WA coral communities are and the extent to which they vary among habitats and regions.

“Even for reefs and species that are relatively well-studied, the patterns of reproduction are complex,” Dr Gilmour said. “Recent work suggests that within a single site on some northern reefs, colonies within the same species may consistently spawn during different seasons (Gilmour et al. 2016, Rosser 2015), leading to massive genetic differentiation and questions of whether, in a reproductive sense, they are considered the same species. Addressing these issues is again confounded by the morphological and reproductive plasticity for which corals are infamous.”

Related links

Gilmour J, Speed CW, Babcock R. (2016) Coral reproduction in Western Australia. PeerJ 4:e2010 doi.org/10.7717/peerj.2010

Gilmour JP, Underwood JN, Howells EJ, Gates E, Heyward AJ (2016) Biannual Spawning and Temporal Reproductive Isolation in Acropora Corals. PLoS ONE 11(3): e0150916. doi:10.1371/journal.pone.0150916

Rosser, N. L. (2015), Asynchronous spawning in sympatric populations of a hard coral reveals cryptic species and ancient genetic lineages. Mol Ecol, 24: 5006–5019. doi:10.1111/mec.13372

The WAMSI Dredging Science Node is made possible through $9.5 million invested by Woodside, Chevron and BHP as environmental offsets. A further $9.5 million has been co-invested by the WAMSI Joint Venture partners, adding significantly more value to this initial industry investment. The node is also supported through critical data provided by Chevron, Woodside and Rio Tinto Iron Ore.

 

Category:

Dredging Science

Home sweet home: identifying prime real estate for deep-water fish

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Curtin University researchers have collaborated on a project which could pave the way for the long-term sustainable management of deep-water fish and their habitat across the Indian and Pacific oceans.

Researchers used predictive species distribution modelling to accurately map the distribution of commercially valuable Hawaiian bottomfish, a fishery which targets a group of deep-water species including snappers, groupers and jacks. These species are distributed, and fished commercially, across the Indo-Pacific including Australia.

The findings identified ‘core’ bottomfish habitat, where all species co-exist, which will allow fishing regulatory bodies to identify the most important areas for management.

The study’s lead author, Dr Cordelia Moore, Curtin’s Department of Environment and Agriculture, said ecosystem-based, or place-based, fisheries management is a new method being adopted globally, and provides a more holistic approach to managing and protecting our marine resources for the long-term.

“Currently there is a lack of detailed information on the spatial distribution of many marine species and the environmental conditions that shape them. This is particularly problematic for deep-water species that are hard to sample, meaning there is less data available to manage their populations,” Dr Moore said.

The study results showed each species responded to a unique combination of environmental conditions, with little overlap, suggesting that effective management of deep-water fisheries must take into account species-specific differences.

Dr Moore said the findings could support the sustainable management of the Hawaiian bottomfish fishery, and provide details for the future management of deep-water fish and their habitats in other parts of the world.

“Most of the species are long lived and can live up to 40 years, which means they have longer to successfully reproduce and maintain a healthy population,” Dr Moore said.

“This makes these populations particularly vulnerable to overfishing and in need of careful management,” Dr Moore said.

The research paper, titled Improving essential fish habitat designation to support sustainable ecosystem-based fisheries management, was published this month in the journal Marine Policy.

The project was a collaboration between Curtin University, the University of Hawaii Deep Sea Fish Ecology Lab, the Australian Institute of Marine Science and the Department of Land and Natural Resources Division of Aquatic Resources via the Sportfish Restoration program.

Can we rely on satellite data to monitor the Kimberley Marine Park?

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Scientists from Curtin University and CSIRO have been investigating how data collected from satellites can help to provide the information needed to monitor the extensive waters of the Kimberley Marine Park.

The Kimberley region is vast and remote, making it difficult and expensive to access and monitor, but satellite remote sensing technologies are providing a cost effective method to gather historical and baseline data with broad spatial coverage and high repeat frequency at metre to kilometre scales of resolution.

A Western Australian Marine Science Institution project has focused on measurements of the turbidity of marine waters using NASA’s MODIS sensor on its Aqua satellite. 

“The murkiness or turbidity of waters directly impacts the amount of light reaching the seabed, so plays an important role in determining what organisms can exist and grow in these environments,” CSIRO’s Dr Nick Hardman-Mountford said.

 

To confidently monitor turbidity through time and quantify how it changes seasonally and between years, it is necessary to know the precision of the satellite-derived measurements. However, as with any derived data, there are uncertainties about how accurate a picture remotely sensing can provide and at what scale. These have not been determined previously for Kimberley waters.

To help remedy this, a key component of the research has been to analyse these uncertainties for remotely sensed turbidity ‘products’ by making comparisons with archived “in water” measurements, and by looking at what resolutions work best.

In situ data was obtained from a number of recent expeditions that occurred along the Kimberley and Pilbara coastline including sites in King Sound, Collier Bay, in the vicinity of King George River, and near Onslow on the Northwest Shelf. Data being used by the team includes specialised optical measurements, as well as measures of turbidity and vertical light attenuation.

The project is due to be completed in December 2016.
 Landsat image pan-sharpened to 15 m resolution. The town of Derby is clearly visible, as well as extensive mudflats exposed at low tide.

 

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Category: 

Kimberley Marine Research Program

Whales from space

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By: Cassidy Newland (AIMS)

It’s as strange as it sounds… researchers are looking for whales in the Kimberley from a vantage point of 770 kilometres above sea level using the Worldview 2 Satellite.

The Satellite captures a spatial resolution of 0.46 metre pixels in the Panchromatic band and a spatial resolution of 1.6 metre pixels in the 8 band Multispectral image (Figure 1).

 

The Panchromatic band captures light across the visible spectrum in a single band and is often displayed as a grey scale image. It has a higher spatial resolution of up to 0.46m, but a lower spectral resolution than the multispectral. The multispectral has 8 bands extending from the far blue through the visible spectrum to the near infra-red providing higher spectral resolution but the spatial resolution is only up to 1.6m.

A number of surveys by different organisations had previously been carried out in the Kimberley by plane, boat and some from land and for the first stage I looked for an image in the World view 2 archive to match one of these.

Although there is a large archive of imagery since the satellite commenced operation in 2009, matching an exact date was difficult and we were lucky to find several images matching surveys conducted in August 2010. I acquired one image which I expected would have the most whales and began the task of looking for them.

At 12-16 metres long you might expect a Humpback whale to be relatively easy to distinguish, but in the multispectral image with 1.6m pixels, a whale seen fully surfaced will only be up to 10 pixels long. Figure 2 shows a simulation based on an actual aerial photo of what a whale might look like in a satellite image.

 

In actuality only a single fully surfaced whale was distinguishable, but with a lot of interpretation and a little imagination a range of whale related features were identified including partially surfaced whales, submerged whales, the foot print of recently surfaced whales, bubble rings from below and even what appears to be a bubble net.

These features are examined in each band to see where they can be best distinguished and determine what band or combination of bands will be used in the analysis to identify further features. There is also testing of the similarity of features within a type and testing of separability of each type. The result is a refined set of features which can then be used to train and verify success of the remote sensing techniques used.

The techniques used included thresholding where cut-off values are defined manually, supervised classifications using the features as training sites and unsupervised classifications where clusters are identified statistically. Of these, thresholding and unsupervised classification provided the best results.

Challenges were noise from shallow water, swell and turbidity, but it was possible to identify surfaced whales, whale footprints, some submerged whales and boats.

 

Related Links:

WAMSI Project 1.2.1 Humpback Whale Distribution project

ABC Kimberley’s Erin Parke talks to WAMSI/AIMS researcher Michele Thums about satellite tagging humpback whales:

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Category:

Kimberley Marine Research Program

Broome boat ramp study indicates boating popularity

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Researchers have analysed a year’s worth of video imagery from the popular Entrance Point boat ramp, adjacent to the Broome Fishing Club, to explore the factors affecting the launching of recreational boats, as part of a broader WAMSI study looking at Human Use in the Kimberley.

In total, 6057 recreational boat launches were recorded by the Western Australian Department of Fisheries camera at Entrance Point during the 12 month study. The figure shows that, despite the town of Broome only having a relatively small resident population of about 13,000 people, boating is a popular activity.

To put it into context, the total at Entrance Point is equivalent to about 22 per cent of the total number of launches per year at Hillarys boat ramp which is one of the busiest in the Perth Metropolitan area.

On a seasonal basis, 60 per cent of all boat launches at Entrance Point occurred during the dry, winter season (May to October) and on a monthly basis, July and August had the highest numbers of boat launches (totals of 825 and 882, respectively).

The average number of boat launches per day generally showed an increase on weekends although from July to September there were increased numbers of launches on weekdays as well.

Throughout the year, the peak in boat launching took place in the morning between 6 am and 10 am.

Mean hourly boat launch rate per month at Entrance Point boat ramp, Broome, from November 2012 to October 2013.

“The results support the original hypothesis that there would be an increase in boat launches during the dry, winter season when there are known to be more visitors (especially ‘grey nomads’) to Broome,” project leader Murdoch University’s Professor Lynnath Beckley said. “However, consistent launching of boats during the wet, summer season (40 per cent of all launches) clearly indicates the importance the residents of Broome place on recreational boating.”

The boat launching data were also explored relative to environmental factors like air and sea temperature, wind speed and direction, rainfall, barometric pressure and tides as well as time of day, day type (weekday, weekend or public holiday) and school holidays.

Time series analyses of the hourly launch data showed that day type, time of day, school holidays and tidal height were significant predictors that together described the most variation in the launches on a daily cycle.  For the weekly cycle, only day type and wind speed were significant predictors.

“The Entrance Point boat ramp is only one of several sites from where recreational boats are launched in Broome and this may have some bearing on the patterns found,” Professor Beckley said. “For example, during the winter mornings when there can be strong easterly winds, many boats are launched instead from the southern end of Cable Beach which is more protected from these winds.”

Entrance Point boat ramp at Broome in peak season (Lynnath Beckley)

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Category:

Kimberley Marine Research Program