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Estuaries in NSW

Major issues for NSW estuaries

Estuary management committees, councils, agencies and the community have identified a great number and variety of issues and problems. These include a complex and diverse range of environmental, socio-economic, management and scientific issues. The following list summaries what is considered to be the most serious issues affecting our estuarine environments.

  • Declining estuarine water and sediment quality.
  • Degradation and loss of estuarine habitats.
  • Unsustainable use of estuarine resources.
  • Lack of long term research and monitoring of estuarine environments.
  • The need for strategic planning in estuarine and coastal environments.

The Department of Natural Resources is working with other agencies in a 'whole of government' partnership with local councils and coastal communities to address these concerns through an integrated planning approach.

To date, over 70 Estuary Management Committees have been established by local councils to oversee the development and implementation of management plans for the longterm sustainable use and development of estuaries in NSW.

This page provides some details about the major issues of concern to estuarine communities.

Declining water quality

Declining water quality and sedimentation are regarded as one of the most serious issues affecting NSW estuaries. Elevated nutrients and sedimentation are largely the result of inappropriate catchment land use practices, sewage discharge and urban run off.

  • Sediments and nutrients

    Elevated nutrients and sediments come predominantly from land runoff, however there may also be a significant contribution of nutrients from coastal upwelling and marine sediments causing entrance shoaling. Land erosion may be a major contributor in rural areas, and sewage and stormwater runoff are major sources in urban areas.

    Sediments infill estuaries and can smother marine life. Excessive nutrients cause eutrophication and excessive growth of algae. Algal blooms are becoming common in many estuaries. Eutrophication poses a serious threat to estuarine ecosystems.

  • Heavy Metals

    Pollution from mercury, lead, copper and other heavy metal is a localised problem. Heavy metal hot spots include Lake Macquarie, Sydney Harbour and the Hunter River. Tributile tin from antifouling paints has been an area of concern in many ports and marinas. Controls on industrial discharges and the use of antifouling paints have reduced heavy metal levels in many areas. Problems remain in areas requiring maintenance dredging or where sediments may be disturbed and resuspended into the water column.

  • Litter

    Litter is a growing and very conspicuous concern for many of our estuaries. Urban areas are most affected. Litter reduces the scenic and recreational values of an area and degrades habitats where it accumulates in areas such as mangroves and wetlands.

Loss of estuarine habitats

Many of the environmental issues relate to water quality and habitat loss, and are overlapping in nature.

  • Degradation of coastal lakes and lagoons

    Estuarine environments throughout much of NSW are declining because of eutrophication and sedimentation, acid sulfate soils runoff, coastal development, loss of habitat and overfishing. Intermittently closed and open lakes and lagoons (ICOLLs), which have restricted exchange of ocean water and tidal flushing, have been particularly affected by catchment runoff.

  • Decline in seagrass

    Seagrass beds are very important ecosystems. Elevated nutrients and sediments have caused serious dieback of temperate seagrass beds in many estuaries. Around half of the seagrass beds in the estuaries of NSW have been lost. The remaining seagrass beds are under threat from inappropriate coastal development and habitat degradation.

  • Loss of mangroves and saltmarshes

    Significant losses of saltmarshes and mangroves have occurred near urban areas through reclamations, drainage and other developments. This affects fish and other marine life, which are dependent on these areas as nursery and feeding grounds.

  • Loss of coastal wetlands

    Significant losses of coastal wetlands has occurred as a result of agricultural drainage, flood mitigation works and other developments. These activities often disturbed acid sulfate soils. Up to 60% of coastal wetlands have been lost or are showing evidence of serious degradation.

Unsustainable coastal development

Urban, industrial and port development, tourism, and other uses have been responsible for significant degradation in the coastal strip of NSW. Rapid population growth and expanding development is affecting estuarine ecosystems.

  • Effects of fishing on estuarine ecosystems

    There is widespread concern about the adverse environmental effects of trawling on benthic communities, on juvenile fish, on by-catch and on changes to the structure of estuarine food webs. The effects of fishing and intensive aquaculture on estuarine ecosystems are poorly understood by resource managers, but it is likely to be significant.

  • Effects of acid sulfate soils

    The disturbance and exposure of acid sulfate soils is of major concern to many coastal communities and stakeholder groups such as professional fishers and oyster farmers. Hotspots include the major rivers on the north coast with extensive floodplains that have drainage works.

    The level of understanding of the impacts of acid sulfate soils on estuarine ecosystems is poorly understood, but it is likely to be both chronic and long term. Mitigation and rehabilitation measures are in the early stage of development.

  • Threats to ICOLLs

    The widespread degradation of intermittently closed and open lakes and lagoons (ICOLLs) is a serious local and national problem. Major causes are elevated nutrients, sedimentation, pollution, inappropriate coastal development, flood mitigation and overfishing. Of particular concern are the unique coastal lakes that are not represented in the less populated and less degraded parts of Australia.

  • Unsustainable use of estuarine resources

    Over-harvesting of fish by commercial and recreational fishers, inappropriate aquaculture, unsustainable tourism, disposal of effluent, draining of coastal wetlands, and conflicting resource use, are critical issues that are often exacerbated by the above issues.

  • Decline in fish stock

    NSW estuaries are not rich in commercial fisheries resources. Declines in commercial fisheries have been experienced in recent years. Reports of serious over-fishing and declines in fish stocks have occurred. There is a serious lack of accurate data on fish catches in many estuaries.

  • Inappropriate fishing practice

    Harvesting practices used by certain commercial fisheries are causing significant impacts of estuarine ecosystems and habitats. Of particular concern is trawling on benthic communities and the effects of by-catch on community structure and estuarine food webs. It is now well recognised that an ESD and ecosystem approach to fisheries management is essential.

  • Unsustainable tourism

    The use of coastal and estuarine environments for tourism and recreation has increased rapidly over the last thirty years. This has had an impact of several sections of the NSW coast. Tourist facilities, infrastructure and accommodation are usually located as close to the attraction as possible. This may affect the natural environment, quality of life and scenic amenity of an area with loss of habitats, declines in fisheries and deteriorating water quality.

  • Disposal of effluent

    Sewage and stormwater runoff are major sources of nutrients associated with urban areas. Most effluent discharged in NSW is tertiary treated but many areas remain unsewered. Problems have been experienced by the oyster industry as a result of human enteric viruses being present in estuarine waters.

  • Draining of coastal wetlands

    Significant losses of saltmarshes and mangroves have occurred near urban areas through drainage and reclamation. Perhaps more significant is the loss of coastal wetlands as a result of agricultural drainage works on coastal floodplains. These losses have affected fish and birds that use these habitats. Drainage may lead to issues associated with acid sulfate soils.

Lack of long term monitoring and research

Little geographically comprehensive and long term scientific information is available on estuarine environments. Without this, it is difficult to accurately assess the condition, to identify trends, and to develop and evaluate management strategies and outcomes.

Local government is highly critical of the State's resource managers and their lack of basic information on estuarine environments, and the lack of simple descriptive resource maps and inventories for estuaries.

Many resource managers and scientists are concerned about the lack of understanding of how estuarine ecosystems function. They argue that effective management must be based on this understanding.

Integration of strategic planning for coastal catchments

Many of the problems identified by coastal communities stem from the lack of integrated, long term planning in coastal catchments. NSW is attempting to address this issue through the NSW Coastal Policy; however, implementation of many of the strategic actions is being delayed due to financial constraints.

Management of coastal catchments must consider

  • the high degree of interconnections between the land and the sea,
  • the many human activities that span the land/sea interface,
  • the wide dispersion of contaminants by tides and currents,
  • the complexity of coastal and estuarine processes,
  • the number and range of stakeholder groups, and
  • the different administrative jurisdictions involved.

Other Issues

  • Social and cultural values of estuaries

    Despite the obvious great importance that the community places on estuaries, the knowledge of the social or cultural values of estuarine environments are limited. Social and cultural values are generally inadequately considered in natural resource planning and management.

  • Lack of non-point source pollution controls

    Guidelines and protocols are being developed for point source discharges. However, limited guidelines have been developed for multiple or diffuse discharges from catchments. Constant low levels of contaminants and pathogens can have serious health and cumulative effects.

  • Condition of urban estuary environments

    Estuaries near the major urban areas of Newcastle, Sydney and Wollongong are the most affected. Some areas of Sydney Harbour, Botany Bay and the Hawkesbury River are heavily polluted by sewage, urban stormwater and industrial discharges, and may be closed at times for bathing and fishing. However, controls are having an effect and most contaminated areas are showing some signs of improvement.