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In this section you will find detailed information, including national overviews and state and regional level assessments, from the 2000-2002 National Land and Water Resources Audit theme assessments.
Australian Catchment, River and Estuary Assessment 2002
National Land and Water Resources Audit, 2002
ISBN 0 642 37125 3
Directions and challenges: investing in the future
Lake Arragon, New South Wales within Yuraygir National Park.
Photo: Department of Land and Water Conservation, New South Wales.
State, Territory and Commonwealth agencies, researchers and community groups have agreed on a series of priorities for improved estuarine management.
Protective management arrangements
Estuary restoration is expensive and often not possible. Protective management arrangements are recognised to be more cost-effective in the long term. The concentration of near-pristine estuaries in northern tropical Australia and western temperate Tasmania, indicates that the different types of estuaries that occur in populated parts of Australia are not well represented in the near-pristine list. The protection of a representative group of near-pristine estuaries from around Australia selected on the basis of estuary type, size, and location would provide a framework for improved nature conservation as well as useful benchmarks for improved understanding and management of Australia's estuaries. This could be achieved through a greater emphasis on estuarine protection as part of the Commonwealth's National Representative System of Marine Protected Areas program.
A part of this initiative might include a National Estuarine Research Reserve System, similar to that established in the United States of America in 1972. The estuary reserves within this category would be chosen to represent the wide range of different estuary types and coastal and estuarine habitats around Australia. Commonwealth, State and local authorities could work together to establish, manage, monitor and maintain the reserves, and to provide for their long-term protection. Research and education are crucial to meeting this goal. The estuary reserves could serve as laboratories and classrooms where the effects of both natural and human activity can be monitored and studied.
Monitoring and assessment
Estuaries are dynamic systems with variable response times. Managers need to be provided with feedback on progress to help understand the time frames required to deliver improvements in estuarine condition. The estuary assessment has highlighted information that is available for Australian estuaries. Significant gaps exist and needs to improve the information include:
- enhanced assessment and monitoring activity and improved integration and reporting of existing activities undertaken by all levels of government and the community;
- agreed reporting frameworks that make information collected at the local level readily available to be rolled up to contribute to initiatives such as State of the Environment reporting;
- increased use of online data warehousing to improve access to and value adding of local, State and Commonwealth data and information;
- use of new technology to capture nationally comprehensive data and information (e.g. the use of remotely sensed imagery to monitor turbidity);
- detailed studies of representative estuaries chosen by type, location, size, condition and process type, with outcomes applied to similar systems;
- involvement of communities (e.g. Waterwatch, Coastcare, Fisheries Action Program ) to gain information on physical parameters (such as depth), habitat type and status, make up and status of fisheries, opening and closing frequency and for the ground-truthing of remotely sensed information;
- assessment and management frameworks to better account for spatial and temporal variation within an estuary;
- assessing and monitoring fish communities to gain a better appreciation of populations, changes, and priorities for estuary protection and rehabilitation to sustain fisheries;
- data presented within appropriate natural resource management frameworks (e.g. population census data by catchment boundaries);
- ongoing attention to selection, evaluation and refinement of attributes for assessing the condition of Australian estuaries and collection of minimum data sets; and
- monitoring and assessment activities need to proceed as a close partnership between land and waterway managers, policy-makers, the interested community and scientific specialists.
Approximately 50 estuaries have been studied in any detail. These have generally been studied because of their proximity to population centres, particular problems or a decline in their condition which has sparked interest in them. A more integrated monitoring program would be of benefit if based on considerations of estuary type, location, condition, beneficial uses and size.
It is unlikely that there will ever be sufficient resources available to monitor all of Australia's estuaries in detail. Even if estuaries were to receive this level of monitoring, better value for money would be investment in intervention strategies to improve and protect estuarine condition. A more cost-effective approach may be to select a small number of representative estuaries from around Australia and investigate their behaviour and management needs in detail and adapt this understanding for other similar systems.
Institutional arrangements
Community groups - key to estuary management.
Photo: Rochelle Lawson.
Commonwealth and State initiatives are essential to address the institutional failings that have resulted from the absence of lead agency responsibilities for estuarine management.
- Lead agency responsibilities need to be clearly defined at a State and Australia level.
An Australia-wide initiative in estuarine protection and management would provide a much needed policy framework for States to implement protective management arrangements through their various agencies and existing legislation.
At a state and regional level catchment management processes need to formally recognise and incorporate estuarine management targets.
Case studies that showcase good estuarine management could be used as a basis for similar programs elsewhere.
Education and awareness
Estuaries are important to, and valued by, Australians. The project has successfully engaged Australians in a national discussion on the condition of our estuaries and their management. Community groups, such as Waterwatch and educational institutions are seeking resources and information on Australia's estuaries and their management. Continued effort in communication will build understanding. From understanding will follow improved management and healthier estuaries.
Management needs for Australian estuaries
Australians are interested in the health of their estuaries. We need to build on this interest with improved management. Key management needs to improve the condition of Australian estuaries based on analysis of the key causes of decline in condition include:
- Undertaking habitat restoration to rehabilitate damaged estuaries.
- Maximising habitat and catchment protection to prevent the degradation of less modified estuaries.
- Minimising nutrient enriched and polluted run-off from urban areas and agricultural catchments. This can be achieved by improving land use management practices, with tertiary treatment and preferably land application of sewage effluent, stormwater retention basins, and with the re-establishment of filter strips, riparian forests and wetlands to trap overland flow of pollutants.
- Implementing catchment management strategies to specifically target and intercept increased sediment loads being delivered to estuaries.
- Control and reduce the likelihood of infestation by invasive species.
- Recognition of the economic and non-market values of estuaries, factoring their net worth for aquaculture, recreation, nature conservation and commercial fisheries into planning decisions such as urban development and infrastructure.
- Development of multiple objective strategies for the management of estuary entrances.
- Restoration of tidal flushing, particularly to tidally-dominated systems, by minimising interference to tidal flows by causeways, bund walls, culverts, floodgates and bridge approaches coupled with strategic dredging to re-establish tidal channels.
Research needs
Cobourg Peninsula, Northern Territory.
Photo: Northern Territory Government.
The Cooperative Research Centre Coastal Zone, Estuary and Waterway Management (Coastal Cooperative Research Centre) with State and Territory agencies and other research providers will continue to build on the work of the Audit's estuary partnership, through a national estuary management network.
Activities include:
- enhancements to the Simple Estuarine Response Model increasing specificity for each of the six subclasses of the process-based classification and re-testing performance against observations from a large number of estuaries;
- linking the Simple Estuarine Response Model to the OzEstuaries database, allowing the model to be run for each estuary in the database, using variables such as depth, length, shape and tidal energy specific to that estuary;
- incorporating the estimates of catchment loads and run-off available for many estuaries from other Audit projects to provide more realistic input into the model. Model predictions will then be compared with observations collated through the estuarine assessment process;
- development of the Australian Estuary Management Handbook;
- reviewing indicators of estuarine health and trialling new indicators; and
- application of remote sensing technologies to gather nationally comprehensive data sets on Australian estuaries.
Strategic research priorities vary for differing estuary types. Certainly there is a need to develop better understanding of:
- advantages and disadvantages of artificially opening coastal lakes and lagoons to provide better advice for entrance opening strategies;
- the importance of the timing and quantities of freshwater flows and effects of change in environmental flows on estuarine ecology;
- the role of fringing mangroves and saltflats in macrotidal, tropical estuaries;
- mechanisms for prevention and control of invasive species;
- impacts of harmful algal blooms and eutrophication in coastal waters (including associated anoxic and hypoxic events);
- the role of extreme climatic events in estuarine condition and predictions on the likely influence of climate change;
- the combined implications of multi-stressors, especially on fish populations;
- effective protective management and rehabilitation strategies;
- links between floodplain and estuary ecology particularly water quality and loss of fishery habitat; and
- the impact of modified fish communities on estuary condition and ecological functioning.
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