Coastal Management
Management IssuesThe management of marine, coastal and estuarine environments is an important component of the Government of South Australia's planning strategy. Opportunities for these environments are explored in terms of management strategies to promote principles of ecologically sustainable development and the protection and development of specific coastal resources. Management issues include:
To download studies and management plans for each of the State's coast protection districts see Coast Protection Districts: Studies and Management Plans. Managing for Sustainable DevelopmentEcologically Sustainable Development (ESD) principles underpin the way in which we need to manage, develop and conserve our marine resources and coastal lands. Proposals for new development or substantial change in use are referred to the Coast Protection Board by planning authorities such as local councils and the Development Assessment Commission for the Board's comment on coastal and marine issues. This referral is part of the planning approval process conducted by the planning authority and is based on whether the development is close to the coast and whether it is on land with a coastal or foreshore zoning. The Board will consider whether the proposal will impact on coastal qualities such as conservation of coastal vegetation, coastal reserves or beaches. The Board will assess the extent of impact, particularly if coastal processes may be affected. In extreme cases, the Board can direct against the development, for instance where the development will cause erosion and no measures are in place to alleviate this impact. In other situations, the Board will advise the planning authority of any aspects of the proposal that conflict with the Board's policies. The Board will also assess whether the proposal may be affected by coastal erosion or flooding due to storm surge, either now or in the future, and advise the planning authorities of these risks. The Board also advises the planning authorities on how land is zoned in the coastal area, and provides technical advice on broader aspects of coastal management, including options for protection of existing development from erosion and coastal flooding. Aquaculture is an important export earner for the State and is expanding. South Australia now has over 160 marine aquaculture enterprises. This growing industry needs careful management to ensure sustainable development. Exploration for minerals and petroleum, still in the early stages, will similarly need careful assessment and integrated planning. Sustainable use is also an issue for marine based tourism. Sandy clean beaches are essential for tourism and recreation but there must be sensitive management of sand dunes and reefs. The large recreational fish take needs careful monitoring, as does recreational boating, which can disturb the seabed near marinas and popular boat ramps. Coastal Planning Information PackageThis Coastal Planning Information Package was initiated by the Coastal Protection Branch, which is part of the Department for Environment and Heritage. The package aims to raise awareness about the role and responsibilities of the Coast Protection Board, which is the statutory authority responsible for managing the State’s coastline and administering the Coast Protection Act 1972, and the role that it has in development assessment. The package also seeks to aid the preparation and review of planning policy relating to coastal and marine issues. Coastal Planning Information Package (1.9Mb PDF) Coastal Environmental Information PackageThe Environmental Information Analysis Branch (DEH) together with the Coastal Protection Branch have now developed a Coastal Environmental Information Package based around the NRM regions to provide additional support for council planners, managers and NRM Boards in dealing with coastal developments and issues Coastal Environmental Information Package (185Kb PDF) Coastal Viewscapes Project
Increasing pressure for coastal development is threatening the scenic quality of South Australia's coastline. The Department for Environment and Heritage initiated the Coastal Viewscapes Project to evaluate and quantify the scenic value of South Australia's coastal landscape as a foundation for the assessment of development applications and the review of Development Plans. The project was carried out by Andrew Lothian of Scenic Solutions. It was an extensive undertaking, with data and photos collected from over 4,000 kilometres of the state's coastline. This was followed by an Internet survey of 2200 respondents to rate scenes and a subsequent Internet survey of over 1600 respondents to ascertain the impact of development on scenic quality. To view the project report and mapping results for regions and
council areas see Coastal Viewscapes Project. The Management of Metropolitan BeachesFor information about the management of metropolitan beaches see Adelaide Coast Protection. Beach Monitoring & Evaluation
Traditionally, coastal management agencies use beach profiles to monitor sand levels on beaches. Since the mid 1970s, a network of beach profiles has been established along the South Australian coast at locations where beach erosion would cause problems to public property and development. The profile lines are regularly surveyed and evaluated for long-term changes in sand levels. Other methods are also employed. Brass rods installed in the seabed along the Adelaide coast are used to measure depth changes due to sand movements. Seabed deepening is a particular issue along the Adelaide coast due to the loss of seagrass. A surface modelling technique is also employed along the Adelaide coast to map and measure large sand movements due to replenishment projects or erosion. This technique involved covering the study area with a grid of surface points and then using surface modelling software to create a surface model. When models surveyed at different times are different, the changes can be mapped and volumes calculated. Where cliff erosion is an issue, a row of spikes located behind the clifftop at set distances are used to measure the clifftop offset. Over time clifftop erosion rates can be determined by this method. Aerial photography also provides a valuable tool for measuring coastal change. The Coastal Protection Branch has a comprehensive collection of aerial photography taken at different times. An instrument called a Zoom Transfer Scope enables two aerial photographs taken at different dates and at different scales to be compared and the differences mapped. Coastline 32 – Monitoring Sand Movements along the Adelaide Coastline (450Kb PDF) Coastline 36 – Recreational Beach Widths along the Adelaide Coastline (1.1Mb PDF) Monitoring reports for some of the State's coast protection districts, including the metropolitan area, are available in Coast Protection Districts: Studies and Management Plans. 
Seagrass LossSeagrasses are very important sediment stabilisers and trappers. A study in Spencer Gulf estimated that seagrass beds, through their ability to trap sediment and create sediment through biogenesis, built vertically at the rate of 1 cm every 100 years. Most of the seagrass beds along the South Australian coast trap beneath them at least 1 m or more of sediment. This sediment is readily eroded by waves and currents if the seagrass cover is lost. As a result, the seabed deepens and the drifting sediment causes problems to surrounding habitats as well as becoming a management problem for coastal structures. Further information on the extent of seagrass beds in South Australia and monitoring details can be found on the Environment Reporting site. Seagrass Loss Along the Adelaide Coast
Approximately 6,000 ha of seagrass has been lost in the Gulf of St Vincent, primarily between Pt Gawler and Aldinga Beach. Seagrass loss along the Adelaide coast between 1949 and 1995 has been mapped, with a total of 4,000 ha having been lost between Largs Bay and Aldinga Beach during this period, 2,700 ha of this between Largs Bay and Marino. Most of the seagrass loss has occurred within 2 km of the shore. 4 km offshore, seagrasses appear to be relatively healthy. Extensive offshore loss occurred around the Pt Adelaide and Glenelg wastewater treatment plant sludge outfalls, but these are no longer in use. The main cause of seagrass loss is deterioration of water quality due to effluent disposal and stormwater run-off. Further information on the extent of seagrass beds in South Australia and monitoring details can be found on the Environment Reporting site. Nutrient-induced epiphytic loading on seagrass communities by algae is a significant contributing factor to seagrass decline. Epiphytes reduce light reaching the leaves and also make the plants more susceptible to damage by waves.
In particular, natural 'blowouts' in the seagrass beds have become unstable. In a natural situation these move within the seagrass meadows relatively unchanged in size and shape through a process of erosion and recolonisation. The erosion rate is matched by recolonisation. In recent years, blowouts have expanded and in many instances have coalesced to form extensive erosion fronts. A shelf of sediment up to 1 m high has been trapped and built
up by the seagrasses (probably over hundreds of years) and, as it
erodes, seabed depth increases.
Monitoring by the Coastal Protection Branch using brass rods installed in the seabed (see photo) shows that, after the initial large depth increase due to movement of the erosion scarp, deepening continues for a number of years after the seagrass has been lost. This depth increase stops when either hard clay calcrete substrate is exposed or the depth reaches the limit of wave action. At Semaphore Park, where seagrass loss occurred in the 1970s, the seabed is still eroding and its depth is increasing at a rate of 1 cm a year. Where seagrass has been lost for many years, such as at Glenelg, clay and calcrete is now exposed in many places. Due to the seagrass loss and depth increase along the Adelaide coast, incoming waves are less affected by friction from the sea floor and therefore reach the shore with more energy. This results in a larger quantity of sand being transported along the coast and greater storm wave impacts. Although not the major cause of beach erosion (which is inadequate alongshore sand supply), seagrass loss is exacerbating erosion of the Adelaide beach by accelerating the overall transport of sand northwards. In addition to these effects, a large quantity of sand is being transported onto the beach as a result of the erosion offshore. It was estimated in 1997 that at least 7.5 million cubic metres of sand has been activated since 1935 as a result of seagrass loss. It was also estimated that 100,000 to160,000 cubic metres is currently being transported each year onto the beach, accumulating at North Haven and Outer Harbor. Much of this is fine sand unsuitable for beach replenishment purposes. For further information consult the brochure Seagrasses of South Australia (350Kb PDF).
Coastal GeomorphologyThe South Australian coastline can be divided into 14 coastal geomorphic zones based on the variability in geology and swell wave exposure. For a description of South Australia's geomorphic regions follow these links to sections from Our Seas and Coasts:
Geomorphological studies for some of the State's coast protection districts are available in Coast Protection Districts: Studies and Management Plans. Coastal VegetationA recurring pattern of dune, clifftop, mangrove and saltmarsh plant communities characterises the South Australian coast. The plant communities comprise a diverse variety of plant species representing a number of plant families. In general, the plants are adapted to cope with the hot, dry conditions and saline environments. The communities form important habitat for a variety of native fauna. They also have a very important role stabilising and trapping marine sediments and forming a protective buffer between the land and the sea. Vegetation studies for some of the State's coast protection districts are available in Coast Protection Districts: Studies and Management Plans. Mapping Mangrove and Saltmarsh Communities
The major aim of the project is to map the distribution of mangrove and saltmarsh habitats in SA, describe the plant communities within them and assess the conservation status of the habitats. The project is being jointly undertaken by the Coastal Protection Branch of the Department for Environment and Heritage and the Information and Data Analysis Branch of Planning SA. The project is divided into three parts:
The major objective of classification and habitat mapping is to compile a statewide digital coverage of the mangrove and saltmarsh habitats to include in the 'Biological Survey of South Australia' database. Habitats have been classified and coded based on landform, lifeform and disturbance. The classification has evolved as the mapping has progressed. A total of 65 habitat codes have been created and applied to the mapping. Transect lines levelled across a number of saltmarshes have been used to survey the plant communities that occur within the different habitats. Transect lines were located according to the following criteria:
Colour aerial photography was used to select transect locations. Eighteen sites across the state have been selected for profile transects. The transects will also form long-term monitoring sites to measure change over time. The conservation assessment has two main aims:
Conservation assessment will involve analysis of the habitat mapping and other relevant spatial coverages.
The Coastal Dune and Clifftop Vegetation Survey
The Coastal Dune and Clifftop Vegetation Survey was funded by the National Estate Grants Program and conducted and supported by the Coastal Protection Branch of the Department for Environment and Heritage. The study described and measured the structure and composition of coastal dune and clifftop plant communities and their relationship to regional and environmental factors. Other objectives of the project were:
849 quadrat sites were surveyed over three years between the Western Australian and Victorian border. The survey also made use of existing quadrat sites from other biological surveys that had a coastal component. The survey added 22,316 plant records to the South Australian Environmental Database and 6,741 specimens were lodged with the State Herbarium. A total of 1,492 plants species were recorded. Of these, 224 were rated as having conservation significance or possible conservation significance, and 30 have Australian ratings. The analysis of the survey data has resulted in 52 floristically distinct communities being described. Regional differences have also been identified. The survey data has been incorporated into the Environmental Database of South Australia, which is a compilation of numerous surveys conducted by South Australian government departments and other organisations. All surveys utilise standardised survey methodology and techniques. A report on the project has been released. The report provides
technical information to help improve conservation, rehabilitation
and management of coastal plant communities. The report comprises
all of the information collected by the survey and the analysis
of the results. For the State Government, the report provides information
that will assist in determining whether existing protection is sufficiently
adequate and comprehensive to protect the variety of communities
along the coast and species that have a threatened status. For local
government and the community, the report provides information that
will ensure that the appropriate plant species for their area can
be selected and used for coastal rehabilitation projects. Information
from the report is being used to develop a handbook on coastal plants
for Coastcare and Landcare groups. The 334 page report titled 'A
Biological Survey of the South Australian Coastal Dune and Clifftop
Vegetation' by Alison Oppermann is available from the Coastal Protection
Branch.
Poster: The Coastal Dune and Clifftop Vegetation Survey (400Kb PDF)
Atlas of South AustraliaAccess to up-to-date and interactive electronic information on the coastal and marine environment is essential for effective decision-making and environmental awareness. The Atlas of South Australia provides access to a range of interactive maps featuring intertidal and marine features such as saltmarsh habitats, aquatic reserves, coastal aerial photography, marine biounits and IMCRA marine bioregions. Simply choose a region you wish to study, then point to 'Land Management' and click on 'Coastal Management'. Coastal Acid Sulfate SoilsCoastal acid sulfate soils (CASS) are potentially present throughout most low-lying coastal regions in South Australia. The Coast Protection Board's strategy for coastal acid sulfate soils has been developed through the Coastal Acid Sulfate Soils Program (CASSP) in Environment Australia to assist South Australian government agencies, individuals and organisations in the identification and management of CASS. CSIRO and the Coastal Protection Branch of the Department for Environment and Heritage (DEH) have been involved with the project. CSIRO has mapped CASS occurrence and analysed soil samples from high-risk areas, and the Coastal Protection Branch has prepared the Board's CASS strategy. The CASS strategy has been prepared in relation to the Board's development and hazard policies, particularly policy 1.3 and policies 2.1 to 2.3 (Coast Protection Board Policy Document (2.3Mb PDF)). Coastal WeedsOur coastline is under threat from plants that are escaping from gardens and becoming serious coastal weeds. Garden escapees, weeds, are a major environmental problem facing our coastline, threatening biodiversity and the preservation of native flora and fauna. Coastline 34 – Garden Plants that are Known to Become Serious Coastal Weeds (850Kb PDF) identifies and addresses a selection of common garden plants that are having significant impacts on our coastal bushland. Coastal Participation GrantsFor information on Coastal Participation Grants, see Coast Protection Board. |
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