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The development of tidal energy in Australia is still a challenge with few studies performed on the characterisation of the resource, due to the difficulty to acquire data and uncertainties about the influence of this anthropogenic activity on the marine environment. Changes in flow could lead to alterations in sediment transport and have further influence on the marine habitat. A case study in a promising area, Banks Strait (Australia), was created using high resolution 2D and 3D models validated against in situ data to investigate changes to hydrodynamic conditions with two scenarios of tidal farms (100 and 300 turbines). Comparison between 2D and 3D is performed to find the best compromise between model accuracy and computational time for preliminary assessment. Changes to current speed and bed shear stress over a 35 day period were found to be localised around the tidal farms and did not extent more than 7 km from the farm (300 turbines) for both 2D and 3D. The results showed that for near field and far field, 2D models are sufficient to give a first approximation of the hydrodynamic influence of tidal farm deployment on its environment.

Anthropogenic impacts on marine habitats are a global problem, particularly in coastal areas. While boulder reefs in temperate waters hold high biomass and biodiversity, and may be unable to recover from anthropogenic stressors without restoration efforts, little is known about how to restore and conserve this important marine habitat. Limited knowledge is a serious impediment to projects aimed at restoring boulder reefs that have been degraded or removed by substrate extraction. In 2008, a boulder reef was restored in Kattegat, the transitional waters between the North Sea and the Baltic Sea, using differently sized boulders. The restored reef covered approximately 27,600 m 2 seafloor and included 100,712 tons of boulders added at depths ranging between 4 and 11 m. This paper describes methodology and lessons learned during the restoration project. Before the restoration, geological and geotechnical surveys confirmed that the sea bed could support added boulders, and high resolution bathymetric surveys provided input for the design of the reef, particularly for numerical modelling of the hydrographic and sediment transport conditions. Numerical modelling was used to derive hydrographic design conditions for boulder placements and further, to ensure that the restored reef would not affect the sea bed morphology and hydrographic conditions at a local harbour and at a protected habitat, both situated in the vicinity of the restoration area. Data on the physical structure of the restored boulder reef, collected in 2009, demonstrated that cavernous structures and shallow reef areas were restored. Moreover, data collected in 2012 confirmed the stability of the restored reef. Finally, results highlighted the importance of stakeholder mapping at the outset, appropriate timing of stakeholder involvement and ongoing consideration of stakeholder perceptions. Charting strategy and introducing a checklist for marine restoration projects, this paper outlines important considerations and methodology needed to ensure that restoration of temperate reef structures meet the objectives, without having undesirable effects on existing hydrographic and morphological conditions, including nearby coastal areas and protected marine habitats.

Effective management of marine environments requires a sound understanding of the relevant physical sedimentary sciences. Environmental impact assessment (EIA) is a key management and decision-making tool employed in Australia for coastal and marine developments. This article examines the veracity of the application of the marine physical sciences within the EIA process, using turbidity measurement and sediment transport pathways as examples. A review of EIA guidance reveals deficiencies in regulation. Turbidity measurement is poorly understood and performed in current practice, while a focus on protecting marine habitats largely ignores those physical sedimentary processes, such as long-term bed-sediment transport pathways, that create and maintain these habitats. Thus evaluations of impacts of offshore activities such as channel dredging and spoil emplacement at sea are fundamentally flawed. An extensive body of scientific knowledge is already available on marine physical processes, and equivale...

A detailed map and dataset of sedimentary habitats of the Milford Haven Waterway (MHW) was compiled for the Milford Haven Waterway Environmental Surveillance Group (MHWESG) from seafloor images collected in May, 2012 using sediment-profile and plan-view imaging (SPI/PV) survey techniques. This is the most comprehensive synoptic assessment of sediment distribution and benthic habitat composition available for the MHW, with 559 stations covering over 40 km 2 of subtidal habitats. In the context of the MHW, an interpretative framework was developed that classified each station within a ‘facies’ that included information on the location within the waterway and inferred sedimentary and biological processes. The facies approach provides critical information on landscape-scale habitats including relative location and inferred sediment transport processes and can be used to direct future monitoring activities within the MHW and to predict areas of greatest potential risk from contaminant transport. Intertidal sediment ‘facies’ maps have been compiled in the past for MHW; this approach was expanded to map the subtidal portions of the waterway. Because sediment facies can be projected over larger areas than individual samples (due to assumptions based on physiography, or landforms) they represent an observational model of the distribution of sediments in an estuary. This model can be tested over time and space through comparison with additional past or future sample results. This approach provides a means to evaluate stability or change in the physical and biological conditions of the estuarine system. Initial comparison with past results for intertidal facies mapping and grain size analysis from grab samples showed remarkable stability over time for the MHW. The results of the SPI/PV mapping effort were cross-walked to the European Nature Information System (EUNIS) classification to provide a comparison of locally derived habitat mapping with European-standard habitat mapping. Cross-walk was conducted by assigning each facies (or group of facies) to a EUNIS habitat (Levels 3 or 5) and compiling maps comparing facies distribution with EUNIS habitat distribution. The facies approach provides critical information on landscape-scale habitats including relative location and inferred sediment transport processes. The SPI/PV approach cannot consistently identify key species contained within the EUNIS Level 5 Habitats. For regional planning and monitoring efforts, a combination of EUNIS classification and facies description provides the greatest flexibility for management of dynamic soft-bottom habitats in coastal estuaries. The combined approach can be used to generate and test hypotheses of linkages between biological characteristics (EUNIS) and physical characteristics (facies). This approach is practical if a robust cross-walk methodology is developed to utilize both classification approaches. SPI/PV technology can be an effective rapid ground truth method for refining marine habitat maps based on predictive models.

This guidance note provides review and recommendations for how the protective services of mangroves and coral reefs can be measured and valued in a manner consistent with national economic accounts and included in other decision-making processes to support planning for development, disaster risk, and coastal zone management. It synthesizes evidence of the role mangroves (chapter 2) and coral reefs (chapter 3) play in coastal protection and risk reduction. It also reviews the tools and approaches commonly used by ecologists, economists, and engineers for estimating the coastal protection services of coastal habitats (chapter 4). Moreover, it examines how the valuations of these coastal protection services can be considered in the System of Environmental Economic Accounts (SEEA), the satellite accounts to the System of National Accounts (SNA) (chapter 5). In addition, the note examines where the coastal protection role of reefs and mangroves has been used in management decisions from local to national scales (chapter 6). Finally, it provides recommendations for advancing the assessment and the use of coastal protection values from coral reefs and mangroves in national and regional decisions (chapter 7).

Accurate and efficient species-based marine habitat assessment is in great demand for the marine environment. Remote sensing techniques including airborne light detection and ranging (LiDAR) derived bathymetry can now be used, in concert with suitable ground truthing, to produce marine habitat maps over wide areas. Hydrodynamic conditions, e.g., current speeds and wave exposure influence habitat types through direct impact on marine organisms, as well as influence on sediment transport and, hence, substrate type. Habitat classification and mapping was carried out using both LiDAR derivatives and hydrodynamic parameters derived from numerical modelling at a location off the coast of Port Hedland in the Pilbara region of Western Australia, 1660 km north of Perth. Habitat classes included seagrass, algae, invertebrates, hard coral, and areas where there is no evident epibenthos. The inclusion of the hydrodynamic parameters significantly increased the accuracy of the classification by 7.7% when compared to using LiDAR derivatives alone.