Highlights of the Coastal Water Habitat Mapping Project

By Professor John Penrose, Center for Marine Science and Technology, Curtin University of Technology, Perth, WA.

The Coastal Water Habitat Mapping (CWHM) Project had as its Objective to “Develop and Apply Technologies for the Rapid and Cost Effective Assessment of Shallow Marine Habitats”. It was supported by a successful Supplementary Funding bid by the Coastal CRC and ran from July 2003 to June 2006. It has been a highly successful exercise in terms of team and capacity building and outcomes and deliverables. In 2003 the CWHM Project linked several then existing CRC partners with new industry, Government Agency and university participants. Figure 1 shows the partners involved in the Project.

go to partner page for details go to page for stake holder companies detail

Figure 1. Coastal CRC and CWHM partners.

The rich talent base provided by the CWHM partnering organizations constitutes a significant highlight in the life of the Project, allowing for rapid project development and execution, such that within the three year lifetime of the agreement, the original aims were rapidly realised and very significantly exceeded. This is most clearly demonstrated by a comparison of the field program originally planned with the much greater field coverage actually achieved. Figure 2 shows the field sites involved in the Project. The number of sites surveyed was over twice the original estimate, while the area surveyed was larger again.

CWHM field sites.

Figure 2. CWHM field sites. See Case Studies

The expanded coverage illustrated in Figure 2 constitutes a Project highlight in its own right and also reflects a dramatic evolution in technological capacity over the life of the Project. The CWHM initiative came about originally because of an expressed concern by an Australian authority over the challenges faced in assessing shallow coastal seabed habitats. Such assessments are increasingly called for as coastal nation states seek to gain understanding of their seabed provinces, a process often associated with the delineation of Marine Parks and related conservation areas. The CWHM Project came at a time when international attention was being directed to finding technologies which could help to meet the cost and effort challenges of providing adequate data and coverage to enable realistic habitat survey programs to proceed. The CWHM Project was charged with progressing its objective in the Australian region, a process which necessarily required effective interaction with the international community. Early in the life of the Project, a successful bid to the Australian Academy of Technological Sciences and Engineering provided additional funding to enable eleven Australian scientists to travel to the University of New Hampshire for an eight day US-Australian workshop on the use of acoustic techniques in seabed habitat assessment. The workshop followed the acquisition by the CRC of a Reson 8125 multibeam sounder system. Multibeam sounders are increasingly the systems of choice for benthic classification when the seabed is not visible to aerial and satellite optical viewing. The workshop helped in rapidly developing the skills of the Australian team in the use of the multibeam unit and in the processing of the very large acoustic data sets it produced. Ten of the Australian participants, who included three graduate students, were involved in the CRC. This experience, together with the opportunities provided by the CRC program for cooperative work across Australia, has led to a very successful team building outcome, a significant highlight of the CWHM Project.

A major highlight of the Project was the emergence of new teaming groups associated with, in particular, a major program of Marine Park mapping carried out in Victoria. This work was preceded by a detailed comparison of a suite of acoustic systems in a test area off the Western Australian coast. Industry partner Fugro Survey, the University of Western Australia and DSTO were involved in the comparison program, which allowed an optimum equipment choice to be made for the very extensive Victorian survey work In the first instance, this involved Parks Victoria, Fugro Survey and the University of Western Australia in a survey of six Marine Parks. Further extensions to the project then included Deakin University. The Victorian program constitutes one of the on-going legacies of the CWHM Project, as does a large suite of benthic surveys now proceeding in Western Australian waters.

The CWHM Project incorporated four sub-projects, CA, Shallow Water Assessment Technologies, CB, Benthic Biology and Habitat Classification, CG, Coastal Geomorphology and Classification and CT, Toolkit of Techniques and Interpretation.

Subproject CA, primarily based at Curtin University, had a major focus on multibeam data processing and interpretation. A highlight of this work was the development of a leading edge processing technique for multibeam data. This drew on the extensive experience of the Curtin group in the field of marine acoustics. Multibeam sounders were originally developed for depth measurement, allowing seabed topography to be mapped over a wide swath beneath the operating vessel. For this purpose the details of the acoustic backscatter pulses from each beam are not used and generally not recorded. A major outcome of the CA subproject was to successfully demonstrate that a combination of topographical information and measures of backscatter strength are together more useful in seabed classification than topography alone. This led to the completion of a robust processing package applicable to multibeam sounder systems. Figure 4 illustrates the effectiveness of the technique in a surveyed area of Morinda Shoals off the Queensland coast. The depth information alone is of value, but the addition of backscatter data significantly enhances discrimination between seabed categories.

Multibeam sounder derived topography and backscatter

Figure 3. Multibeam sounder derived topography and backscatter, Morinda Shoals, Queensland

A second highlight of CA was the emergence of a new application for multibeam data sets, the use of such systems in mapping mid-water targets. This work, carried out with assistance from industry partner Sonardata, is likely to form part of the new generation of multibeam applications. Figure 4 shows an illustration of target signals derived from one swath return, in the white image, and a representation from a succession of such records, showing two distinct target groupings, of differing scattering strengths.

Seabed and midwater target returns from one swath record (upper image) and from a succession of such records.

Figure 4. Seabed and midwater target returns from one swath record (upper image) and from a succession of such records. Both images show regions of small targets in the upper water column and larger targets below.

Subproject CB, largely based at the University of Western Australia involved a wide range of activities and drew on the extensive group experience there in the biological dimensions of marine benthic survey. One highlight of CB was the development of a suite of techniques for optimal processing of underwater video data. Such data is needed to inform the interpretation of acoustic data sets and also for detailed studies of mobile and sessile marine life. The interpretation of underwater video and photographic records is commonly very labour intensive. The CB work included the development of techniques to address this issue. Figure 5 shows an example of a screen display for one such tool, JEHP. This enables major dimensions of a target organism to be rapidly estimated and also provides software and display facilities to facilitate rapid data entry. Figure 6 shows a screen display from a stereo camera facility, which enables length measurements to be made from images of mid-water targets.

Screen display for JEHP measurement and classification tool.

Figure 5. Screen display for JEHP measurement and classification tool.

Length measurements from stereo imagery.

Figure 6. Length measurements from stereo imagery.

Subproject CB also contributed key inputs to survey planning and interpretation. Figure 7 shows details of a video sampling design developed for an area around Point Hicks, as part of one of the Parks Victoria surveys. The projected video tracks were developed based on a full coverage multibeam survey carried out by industry partner Fugro Survey.

Video sampling design for Point Hicks Marine Park and adjacent areas

Figure 7. Video sampling design for Point Hicks Marine Park and adjacent areas.

Subproject CG, based at Geoscience Australia in Canberra, brought wide experience in coastal geology and geomorphology to the CWHM project. In addition, Geoscience Australia provided data archiving support for the very large multibeam data sets generated from the CWHM project. In a number of the sites shown in Figure 2, the CG team carried out detailed coring and sedimentary analysis and sub-bottom profiling studies. This work constituted a significant highlight of the CWHM project, as it provided substrate information not obtainable from the other CWHM components. Figure 8 shows some results from sediment coring in Cockburn Sound, Western Australia.

Coring details from east-west transects, Cockburn Sound Western Australia

Figure 8. Coring details from east-west transects, Cockburn Sound, Western Australia

Sub-bottom profiling and seabed topography results Keppel Bay Queensland

Figure 9. Sub-bottom profiling and seabed topography results, Keppel Bay, Queensland

Subproject CT was a key component of the CWHM project, and of the CRC program as a whole. Its purpose was to make readily available to marine managers and the general public the outputs of the CWHM project. A highlight of CT was the completion of a website which combines attractive, readily accessible material with links to professional level reports and material developed by the CWHM project and also to related international sites. Figure 10 shows most of the entry page of the CT Toolkit website.

The Coastal Water Habitat Mapping Toolkit website entry page.

Figure 10. The Coastal Water Habitat Mapping Toolkit website entry page.

The Coastal Water Habitat Mapping Project has been outstandingly successful and had led to substantial on-going research and applications. The CWHM team are to be congratulated. Rob McCauley and the CA team, Gary Kendrick and the CB team, Brendan Brooke and the CG team, Bill Russell-Cargill for his work on CT, Des Lord for his many great contributions, our industry partners Fugro and Sonardata and Les Hamilton and DSTO have together made the CWHM Project a major success.

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