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SoE 2009 > Water > 6.6 Estuaries and coastal lakes

Chapter 6: Water

6.6 Estuaries and coastal lakes

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6.6 Estuaries and coastal lakes

New South Wales estuaries and coastal lakes are coming under increasing pressure from coastal development.

The condition of NSW estuaries is highly variable. While most have been modified to some extent, around 10% remain in near-pristine condition, while some others have been highly disturbed. The overall condition of estuaries generally reflects the level of disturbance or naturalness of their catchments and is related to surrounding land uses.

Catchment disturbance leads to habitat modification and changes in runoff characteristics, with increased levels of sediments and nutrients having an impact on estuarine water quality and ecosystem health.

Deterioration in quality is generally associated with high levels of urbanisation, catchment development and modification to waterways. While significant progress has been made in improving estuary management, the pressures of population growth and urban development along the NSW coast are predicted to increase in the future.

Maintaining the health of estuaries while enabling population growth requires continued improvement of catchment management practices, better planning and urban design processes and more effective management of diffuse runoff and urban stormwater.

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NSW indicators

Indicator and status


Information availability







Catchment disturbance



Notes: Terms and symbols used above are defined in About SoE 2009 at the front of the report.

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Estuaries occur where creeks and rivers meet the sea and occupy the transition zone between the freshwater and marine environments. They are semi-enclosed water bodies that experience gradients in salinity, temperature and turbidity. At their lower end they have a permanent or intermittently open connection to the sea, while their upstream boundary is the limit of tidal influence in a river or creek.

Estuaries are highly productive natural systems forming the basis of complex food webs that underpin life in near-shore waters and marine environments.

The desirability of coastal lifestyles and increasing settlement along the coast are placing estuaries and coastal lakes under ever greater levels of stress. The attendant pressures of development and urbanisation, and disturbance of the natural values of surrounding catchments need to be carefully managed in order to protect the health and preserve the condition of estuarine environments.

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Status and trends

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Estuary types

Estuaries along the NSW coast vary as a result of their geophysical setting. The north coast is generally characterised by broad coastal floodplains that have been extensively cleared and settled. The Sydney Basin is highly urbanised with drowned river valleys that cut through a sandstone plateau. The south coast is characterised by smaller catchments with less development and a coastline of embayments.

Estuaries in NSW may be grouped into five major classes based on their geomorphology. These are described in Table 6.13 in broadly decreasing order of oceanic influence.

Table 6.13: Estuary types in NSW

Estuary type

Number in NSW




These are semi-enclosed bays characterised by marine waters with little freshwater inflow, such as Botany Bay and Jervis Bay

Tide-dominated drowned river valleys


Drowned valley estuaries typically occupy deeply incised bedrock valleys that are aligned to the coastal trend and open into semi-protected bays. The Hawkesbury River estuary flowing into Broken Bay is an example.

Wave-dominated barrier estuaries


Wave-dominated estuaries have tidal inlets that are constricted by beach sand deposited by waves and flood-tidal deltas. Barrier estuaries, with open but constricted inlets, are associated with larger rivers whose discharges tend to counteract the influence of wave-transported beach sand in the estuary mouths. They occur behind sand barriers on exposed sections of the coast. The Clarence, Richmond, Manning and Hunter rivers are examples.

Intermittent estuaries (saline coastal lagoons and creeks)


Intermittent estuaries are coastal water bodies that, for a combination of climatic and other reasons, become isolated from the sea for extended periods of time. Saline coastal lagoons and small coastal creeks occur in similar settings to barrier estuaries but, because of small catchments and river discharges, their mouths are blocked by beach sand for much of the time. The unpredictability of rainfall means that the opening behaviour is intermittent and erratic and the salinity regime of these types of estuaries is highly variable. Examples of relatively large saline coastal lagoons are Smiths Lake, Coila Lake and Dee Why Lagoon. Many of the small coastal creeks are infilled (mature) coastal lagoons.

Brackish lakes


Generally connected to the ocean by a long creek and hence have extended flushing times allowing freshwater inflows to dominate. Myall Lakes is an example.

Source: Roy et al. 2001

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Condition of estuaries and coastal lakes

Generally there is a lack of systematic data to determine the overall condition and long-term trends for the health of estuaries and the important ecosystems they support. A previous assessment (NLWRA 2002) described the variability in the condition of NSW estuaries, with 10% classified as near-pristine, 38% slightly modified, 26% modified and 26% severely modified.

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Water quality

The health of estuarine ecosystems and the food webs they support is heavily influenced by water quality. While water quality is naturally highly variable across different estuaries, over time pressures on water quality can lead to a loss of diversity and reduced ecosystem health.

Water clarity or turbidity

Water clarity is an indication of the amount of particulate matter in the water, which may consist of clay and silt particles, phytoplankton or natural tannins. Measuring turbidity provides an indication of the amount of light available for aquatic plants and other benthic organisms that inhabit the water column and substrate of estuaries.

The turbidity of 27 estuaries was sampled for the period 2005–08 and assessed according to the percentage of samples complying with trigger levels thought necessary to protect estuarine ecosystems (ANZECC & ARMCANZ 2000). Of the estuarine locations monitored, only four (15%) complied with trigger levels more than 90% of the time while 13 (48%) complied with trigger levels less than 75% of the time (Figure 6.10).

Water clarity on the north coast is generally poor to very poor with all samples exceeding the trigger levels for 50% of the time compared with only one of the estuaries sampled on the south coast. The water clarity in drowned river valleys, coastal rivers and permanently open barrier estuaries is generally below trigger levels except during periods of flooding after heavy rain. Elevated levels of suspended particulate matter have been measured in coastal lakes and lagoons, particularly those close to major urban centres.

Figure 6.10: Water quality sampling from selected NSW estuaries, 2005–08

Figure 6.10

Download Data

Source: DECC data 2008

Notes: Estuaries sampled for turbidity were not the same as those sampled for chlorophyll-a and the total number of estuaries is different for each water quality parameter.


Beachwatch programs monitor recreational water quality at swimming beaches in NSW. While not an assessment of overall water quality, the results provide an indication of sewage and stormwater pollution which affects the fitness of water bodies for human recreational use as well as the effectiveness of stormwater management.

In coastal areas, the summer of 2007–08 was the wettest in 24 years and while the attainment of 90% compliance with guidelines at ocean beaches was much improved over the previous wet period 10 years ago, performance slipped at estuarine beaches. Only about 30% of estuarine beaches achieved this outcome, due to their lower capacity to dilute and flush pollution. This indicates that there is still a need to improve the management of stormwater inflows to estuaries in urbanised catchments. Water 6.5 has further information on the Beachwatch Program.

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Ecosystem health


Abnormally high levels of chlorophyll-a indicate high phytoplankton levels or algal blooms and are a symptom of eutrophication, the over-enrichment of a water body with nutrients. High levels of algae may lead to reduced levels of dissolved oxygen in the water column and some algal species may produce toxins which have serious implications for fish, shellfish and humans coming into contact with the water. Higher levels of chlorophyll-a are generally recorded in the summer months when warmer temperatures and more light provide better growing conditions.

As part of a statewide pilot program, chlorophyll-a sampling results for 65 estuaries were compared with trigger levels thought necessary to protect estuarine ecosystems. Trigger values were adjusted for estuary type depending on their ability to dilute and flush catchment inputs in accordance with the recommendation of the ANZECC guidelines for water quality (ANZECC & ARMCANZ 2000). Data for the period 2005–08 was assessed according to the percentage of samples complying with trigger levels.

Of the 65 estuarine locations monitored, only seven (11%) achieved compliance with trigger levels more than 90% of the time while 30 (46%) were lower than trigger levels 75% of the time (see Figure 6.10).

Individual estuaries are highly variable in their physical characteristics and dynamics, with the ANZECC guidelines stating that exceedences of trigger levels do not automatically indicate that estuarine conditions are poor. Instead, any pattern of exceedences is a cue that the water body should be investigated further to determine whether water quality issues do exist.

It is usually the case, however, that chlorophyll-a concentrations at locations that receive a relatively large nutrient load for their size and where water exchange is slow, such as Avoca Lake, Manly Lagoon, Fairy Creek and Mollymook Creek, consistently exceed trigger levels.

Distribution of seagrass

Seagrasses occur in the intertidal and subtidal zones of estuaries. Barrier estuaries contain the largest seagrass beds, with four of these accounting for more than 60% of the total area of seagrass in NSW: Wallis Lake (30%), Clarence River (15%), Lake Macquarie (10%) and Tuggerah Lakes (7%). Intermittently closed and open lakes and lagoons generally contain little or no seagrass.

The first systematic mapping of seagrass in NSW was created from aerial photos taken in the 1970s (West et al. 1985). More recent surveys have used refined mapping techniques (Williams et al. 2006) and indicate that the total area of seagrass in NSW is approximately 161 square kilometres. Comparison across time appears to reveal some significant losses and gains, but a substantial component of these changes may be attributable to artefacts or inconsistencies between the mapping processes (West & Williams 2008).

Seagrasses have now been shown to be quite dynamic in nature with substantial movement in distribution during this period and cyclical patterns of loss followed by slower periods of regeneration and regrowth. The overall pattern of seagrass distribution in Sydney Harbour appears to have slightly increased during the 1980s, followed by a slow decline since (West et al. 2004; West & Williams 2008).

The natural variability of seagrass communities and lack of consistent mapping prior to the 1970s makes it difficult to assess their overall status or trends in distribution. It is believed there has been an overall decline in the extent of seagrasses since European settlement, but this is difficult to quantify. Based on the historic evidence available, Keith 2004 has estimated the loss at less than 30%.

Seagrass losses due to human disturbance have been recorded in a number of highly modified estuaries. The predominant cause of this decline has been impaired water quality due to increased levels of sediments and nutrients, which leads to reduced levels of light to support their growth. Physical disturbance, changes to hydrological flows and natural phenomena such as storms also play a role. Seagrass decline has been documented since the 1940s for urbanised locations such as Port Hacking and Botany Bay (Larkum & West 1990; Watford & Williams 1998; Williams & Meehan 2004).

Distribution of mangroves

Mangroves grow along the shores of many NSW estuaries, in some places forming extensive forests. Five species occur in the state. Two are widespread across the whole NSW coast, but the Tweed River is the only estuary in which all five species are found. Three major estuaries – Port Stephens and the Hunter and Hawkesbury rivers – account for approximately 50% of the total distribution of mangroves in NSW.

The first systematic mapping of mangroves and saltmarsh habitats for NSW was created from aerial photos taken in the 1970s (West et al. 1985). Recent surveys have recorded approximately 125 km2 of mangroves in 86 estuaries and embayments.

Mangroves are quite resilient and are able to rapidly colonise favourable areas. It appears that there may have been some expansion in the extent of mangrove during the period of the recent surveys, especially as clearing of them has slowed since the introduction of measures to protect coastal wetlands. Any expansion may be due to a range of factors and, on balance, the ecological consequences of these processes are difficult to assess. Factors include:

  • regrowth of past clearing
  • colonisation into areas of saltmarsh
  • colonisation of new areas where altered hydrology and tidal regimes are favourable to mangroves.

Recent studies have described a general trend of mangrove habitats expanding into saltmarshes (Saintilan & Williams 1999; Saintilan et al. 2009).

A lack of consistent mapping makes it difficult to assess overall trends in the status and extent of mangroves. It is believed that there has been an overall decline in the extent of mangroves since European settlement, but this is difficult to quantify. Based on the historic evidence available, Keith 2004 has estimated the loss at between 30 and 70%.

Distribution of saltmarsh

Coastal saltmarsh occurs on the shores of estuaries and lagoons that are permanently or intermittently open to the sea. It is frequently found as a zone on the landward side of mangrove stands. Saltmarsh occurs at the upper levels of the intertidal zone and while not subject to daily tidal inundation, the habitat is flooded by larger tides. Saltmarsh was recently recorded in 92 NSW estuaries with the total area estimated at 60 km2.

There has been a substantial decline in the extent of saltmarsh since European settlement, but this is difficult to quantify. However, based on the historic evidence available, Keith 2004 has estimated the loss at 30–70%. Losses of saltmarsh have been particularly severe in the Sydney region and on the central coast (Wilton 2002; Williams & Meehan 2004; Kelleway et al. 2007). Saltmarsh has been listed as an endangered ecological community in NSW due to the nature of ongoing losses.

Saltmarsh is globally threatened and many of the threatening processes identified operate in NSW, including infilling, modified tidal flows, weed invasion, human disturbance and climate change (Adam 2002). A recent trend has been the loss of saltmarsh due to intrusion by mangroves (Saintilan & Williams 1999; Saintilan et al. 2009).

Fish assemblages

The Estuarine Fish Community Index was developed for application to South African fish communities and is now being trialled in NSW estuaries. It is a multi-metric index that combines four broad fish community attributes – species diversity and composition, species abundance, nursery function and trophic integrity – into a single measure of estuarine condition. The community attributes are made up of 14 individual metrics which have been found to respond in a predictable manner to environmental conditions.

In a pilot study in 2008, three estuary types were defined within the central bioregion of the NSW coast and sampling conducted in each type using seine or gillnets. While there has been no recent sampling of estuarine fish in the northern and southern bioregions using comparable protocols, some data from a statewide survey in 1999–2002 was available for comparison.

Of the 78 estuaries for which data is available, when compared to reference condition, the majority of estuaries were found to be in moderate condition. However, at this point the outcomes of this monitoring are still largely experimental in nature.

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The growth of population along the coast has had a number of impacts on estuaries as a consequence of land clearing and development. These activities have increased runoff and stormwater which carries sediment and other pollutants to coastal environments. Areas of mangroves, saltmarsh and seagrass have been reclaimed for port infrastructure, recreation, housing and rubbish disposal. Land clearing, pollution, drainage works and effluent disposal give rise to issues that affect many coastal communities adjacent to estuaries.

Land-use activities in coastal catchments can also have a significant impact on coastal and estuarine environments, primarily through a reduction in coastal water quality. Diffuse runoff and discharge of effluents can introduce nutrients, pollutants, suspended sediments and other contaminants to estuarine and coastal waterways.

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Catchment disturbance

Changes in land use and the removal of vegetation in coastal catchments are good indicators of the pressures affecting water bodies from increased loadings of nutrients and sediments from diffuse sources (Map 6.5). Where vegetation has been cleared, the nature of the alternative land use will determine by how much the level of runoff increases. Increasing urbanisation leads to greater runoff from the hard non-porous surfaces found in urban areas.

The average rate of vegetation clearance in all estuary catchments in NSW is approximately 40%. Almost 10% of coastal catchments remain in near-pristine condition with little or no clearing and an additional 15% have catchment clearing levels of less than 10% (Table 6.14). The majority of these coastal catchments and estuaries are within the public reserves system of national parks or other public lands.

Table 6.14: Level of clearing of coastal catchments in NSW

Area of catchment cleared

Number of catchments

Less than 1%














Source: DECC data 2008


Map 6.5: Population pressures and catchment disturbance in NSW estuaries and coastal lakes

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Population and demographic change

The majority of the NSW population lives close to the coast and this places considerable pressure on coastal and estuarine ecosystems through increased development and disturbance of the catchments (Map 6.5).

The average population density for coastal catchments is approximately 255 people per square kilometre. It ranges from nil in estuaries located in national parks to the highest densities in metropolitan Sydney. Dee Why catchment has over 2700 people per km2 and the Cooks River over 3400. Other estuaries with high population densities include Sydney Harbour, Parramatta River, Georges River, Botany Bay, the lagoons on Sydney's northern beaches, Wollongong and the Central Coast.

Population growth is an important driving force that may have significant implications for coastal catchments and ecosystems. The population of coastal NSW is growing at a higher rate than the state average, particularly around the major metropolitan areas and on the north coast.

Outside of the major metropolitan areas between Newcastle and Wollongong, the population increased by 67% between 1981 and 2001. Growth rates still remain above the state average as a whole, but have declined from their 1980s peaks. LGAs with significant growth include Eurobodalla, Port Stephens, Tweed and Byron. LGAs with low growth or decline include Lismore, Richmond Valley and Grafton (Parr 2004).

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Nutrient and sediment loads

Many NSW coastal waterways are subject to the threats of eutrophication (excessive nutrient enrichment) and sedimentation. Urban development of coastal catchments and some agricultural land-use practices have the potential to substantially increase the rate of sediment and nutrient inputs to coastal lakes and estuaries.

Increases in nutrient loads may lead to excessive production of algae and aquatic plants, with flow-on effects up the food chain. Overall system productivity may be increased temporarily, but excessive levels of nutrients tend to favour a small number of species while overall biodiversity and ecosystem health is reduced. High levels of total suspended sediments can smother sensitive species and limit primary production by reducing the levels of light.

Changed loads of nutrients and sediments are generally a consequence of catchment disturbance but direct measurement of sediment and nutrient loadings to coastal lakes and estuaries is costly. Sediment and nutrient loads have therefore been estimated using broadscale catchment models that link land-use type and change, and long-term average rainfall conditions to sediment and nutrient emissions loads.

This modelling has been applied to determine the percentage increase above natural levels of total suspended sediments, total nitrogen and total phosphorus. Figure 6.11 shows the results for suspended sediments and demonstrates that while some estuaries still have nearly natural loads, in many others loads have increased significantly above natural, undisturbed levels. An estimated 55% of NSW estuaries have undergone a doubling of loads of total suspended sediments.

Figure 6.11: Modelled loads of total suspended sediments to NSW estuaries

Figure 6.11

Download Data

Source: DECC data 2008

The results for nutrients are similar (Figure 6.12) with an estimated 48% of NSW estuaries experiencing a doubling of nitrogen levels and 73% a doubling of phosphorus levels.

Figure 6.12: Modelled loads of nutrients to NSW estuaries

Figure 6.12

Download Data

Source: DECC data 2008

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Commercial and recreational fishing

Commercial fishing is carried out in 54 NSW estuaries, the main areas being the Tweed River, Richmond River, Clarence River, Nambucca River, Camden Haven, Manning River, Wallis Lake, Smiths Lake, Hunter River, Lake Illawarra, Coila Lake and Wallaga Lake.

No statewide survey of recreational fishing has been attempted since the National Recreational and Indigenous Fishing Survey in 1999. Recreational fishers are the major harvesters of several key species in NSW. Recreational anglers are estimated to take more than 70% of the total harvests of popular estuarine and coastal species, such as bream, mulloway, and dusky and blue-spotted flathead (Gray 2008).

The state has 137 commercial shellfish-growing sites from Tweed Heads in the north to Eden in the south. Poor water quality can significantly affect the food safety of filter-feeding shellfish, such as oysters and mussels. Table 6.15 describes the status of the designated shellfish harvest areas in NSW.

Table 6.15: Status of shellfish harvest areas in NSW, August 2009





Harvesting and direct sale permitted



Harvesting restricted to certain times with depuration



Harvesting not currently permitted at any time


Source: DII data 2009

Notes: 'Depuration' is the purging of the gastrointestinal contents of harvested shellfish in land-based facilities containing clean estuarine water.

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Invasive species

Caulerpa taxifolia is a fast-growing seaweed that has colonised various areas outside its natural range, including several NSW waterways. Caulerpa was first found in NSW in April 2000 and has now spread to 14 estuaries and coastal lakes in the state.

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Other pressures

Tidal flows may be affected by seawalls designed to keep estuary entrances open, the artificial opening of lagoon entrances to enhance circulation and flushing, and flood mitigation structures. Changes to hydrology and flows can have a significant impact on salinity levels and the composition of estuarine ecosystems. Foreshore structures, such as reclamation walls, jetties and moorings and aquaculture facilities, also cause disturbance to natural systems, both through the construction and placement of the structure, and the activities associated with them.

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Climate change

The potential impacts of climate change and sea level rise are becoming increasingly apparent and more widely recognised (see the Climate Change Chapter). It is predicted that sea surface temperatures and sea levels will continue to rise and that ocean currents will be modified. These changes will affect coastal weather patterns, ocean acidification, coastal erosion, flooding and inundation.

The potential impacts of climate change on estuarine ecosystems include:

  • increased saltwater intrusion into estuaries
  • altered flushing characteristics, tidal ranges and salinity regimes
  • changes to sediment and nutrient dynamics
  • changes in water quality.

These will result in changes to habitat and community distribution. Some communities, such as mangroves, are resilient and are likely to colonise newly favourable areas while receding where conditions are less favourable. Others, such as saltmarsh, are likely to come under greater pressure, as in many locations their landward advance in response to greater inundation will be blocked by coastal development.

Currently a large proportion of the NSW population lives in coastal settlements where the potential impacts of sea level rise are likely to be felt. In the short to medium term, periodic inundation of low-lying areas and foreshore erosion are potential threats, while permanent inundation and realignments of the shoreline are expected in the longer term. Low-lying areas and beachfront and foreshore properties are likely to be most affected. Coastal development too close to the shoreline will generally reduce flexibility and impede the natural physical and ecosystem processes of shoreline realignment.

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Management of the NSW coastal zone is the responsibility of all levels of government. The anticipated growth in coastal population is likely to increase the importance of integrated coastal zone management and climate change adaptation strategies.

Local government plays a key role in protecting the health of estuarine ecosystems through a variety of mechanisms including land-use and strategic planning, development controls and a range of policies affecting water utilities and water quality management, such as sewage and stormwater management strategies and estuary management plans.

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State Plan 2006

State Plan 2006: A new direction for NSW (NSW Government 2006) has the following target under Priority E4: 'By 2015 there is an improvement in the condition of estuaries and coastal lake ecosystems'. A Monitoring, Evaluation and Reporting (MER) strategy is being implemented to monitor progress towards all E4 targets.

A review of State Plan 2006 commenced in August 2009 and this may adjust some of the plan's priorities and targets.

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The NSW Environmental Planning and Assessment Act 1979 sets the framework for land-use planning decisions. The Coastal Protection Act 1979 and the NSW Coastal Policy 1997 (NSW Government 1997) provide the strategic direction and legislative framework for managing the NSW coastal zone. Mangroves and seagrass habitats are protected under the Fisheries Management Act 1994.

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State environmental planning policies

State environmental planning policies (SEPPs) address specific planning issues in NSW.

State Environmental Planning Policy No. 71 – Coastal Protection commenced on 1 November 2002 and ensures that:

  • development in the NSW coastal zone is appropriate and suitably located
  • there is a consistent and strategic approach to coastal planning and management
  • there is a clear development assessment framework for the coastal zone.

State Environmental Planning Policy No. 14 – Coastal Wetlands ensures coastal wetlands are preserved and protected for environmental and economic reasons. The policy applies to coastal local government areas outside the Sydney metropolitan area and identifies over 1300 wetlands of high natural value from Tweed Heads to Broken Bay and Wollongong to Cape Howe. All land clearing, construction of levees, and drainage work or filling requires consent and preparation of an environmental impact statement.

Other SEPPs relevant to coastal development include:

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Plans and planning processes

Estuary management plans: The statewide Estuary Management Program was developed in response to concerns about the condition and health of NSW estuaries. Estuary management plans have been prepared for 65 estuaries in order to achieve integrated, balanced and ecologically sustainable management. They are being implemented by local councils.

Regional strategies are prepared by the Department of Planning to guide and manage the high rate of population growth in coastal regions in a sustainable manner while protecting valuable natural and cultural assets. The strategies require:

  • local environmental plans to protect and zone lands with aquatic, riparian and wetland conservation values
  • councils to undertake an investigation of lands potentially affected by sea level rise to ensure that risks to public and private assets are minimised and managed.

Catchment action plans are developed by catchment management authorities and represent the key process that coordinates and drives natural resource management at the regional level. The plans describe the approaches to be adopted for addressing statewide targets at the regional scale and also specify regional targets and programs of investment and works that will achieve these outcomes.

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Comprehensive Coastal Assessment

The Comprehensive Coastal Assessment (CCA) was a key element of the NSW Coastal Protection Package aimed at informing planning along the state's coast. The CCA toolkit was released in 2007 to assist councils, government agencies and others better manage coastal areas. It provides data on the physical, biological, social and economic values of the NSW coastline as well as models to assist with planning. The CCA toolkit study area extends in the north from the Tweed to Port Stephens and from Shellharbour to the Bega Valley in the south.

Projects funded under the CCA include:

  • a comprehensive database of aquatic and estuarine habitats with data on the extent of seagrass, mangroves and saltmarsh, and fish communities
  • mapping of coastal sedimentary deposits
  • modelling of the flushing characteristics of a range of permanently open estuaries and intermittently closed and open coastal lakes and lagoons on the NSW coast
  • development of broadscale catchment modelling which links land-use type and long-term average rainfall conditions to nutrient emissions (total nitrogen and total phosphorus)
  • completion of pilot sustainability assessments and management strategies for seven priority coastal lakes (Cudgen, Myall, Burrill, Narrawallee, Coila, Merimbula and Back).

The Coastal Eutrophication Risk Assessment Tool is a modelling tool that provides catchment and estuary managers with guidance about the effects of catchment land use on the health of NSW estuaries. It provides an assessment of the sensitivity and potential for eutrophication in NSW estuaries and identifies likely sources of nutrient generation in catchments. Detailed modelling frameworks are nearing completion for riverine estuaries and coastal lagoons.

The Coastal Lake Assessment and Management Tool is a decision support tool to assist in carrying out sustainability assessments for coastal lakes. The tool is designed to be the basis for the development of management strategies. Currently local councils are undertaking nearly 20 sustainability assessments to either support development of estuary management plans or review and update existing plans.

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Management of water quality

The main responses aimed specifically at improving estuarine water quality by reducing pollution include:

  • planning strategies covering land-use and catchment management, which set water quality objectives
  • licensing or management of pollution from major point sources
  • programs to prevent and manage pollution incidents.

The NSW Water Quality Objectives set out the agreed environmental values and long-term goals for NSW's surface waters. The objectives are consistent with the agreed national framework for assessing water quality described in the ANZECC Guidelines (ANZECC & ARMCANZ 2000). They set out a range of water quality indicators and criteria to determine whether water quality in estuaries and coastal lakes is able to support healthy ecosystems and a range of beneficial uses, including drinking water and recreational activities.

Released in 2009, the NSW Diffuse Source Water Pollution Strategy (DECC 2009b) recognises that diffuse source pollution now accounts for the majority of the pollution load in NSW waterways. The strategy aims to coordinate the NSW Government's approach to the management of diffuse water pollution and identifies a list of actions to be implemented.

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Climate change

The NSW Government has adopted the Sea Level Rise Policy Statement (DECCW 2009) which will help coastal councils and Government agencies take into account future sea level rise in their planning. The statement sets sea level rise benchmarks of 0.4 metres at 2050 and 0.9 m at 2100.

A key conclusion of the most recent assessment by the Intergovernmental Panel on Climate Change (IPCC 2007) is that reactive and stand-alone efforts to address the impacts of climate risks to coastal ecosystems are less effective than responses that are consistent with the principles of integrated coastal zone management. This is widely recognised as the most appropriate approach to deal with climate change, sea level rise and other current and long-term coastal challenges, such as coastal hazards and environmental degradation. The principles of integrated coastal zone management underpin all of the major NSW programs to manage estuarine and coastal resources, including coastline management plans and estuary management plans.

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Future directions

The strong preference of many Australians to live near the coast means that it is likely that pressures on the NSW coastal zone will continue to grow, due to expanding population and development.

The poor condition of water quality in some highly urbanised estuaries suggests that stormwater runoff and new urban development should be better managed in order to maintain the health of estuaries and coastal lakes.

More effective implementation of the principles of integrated coastal zone management is likely to lead to improved outcomes for estuaries and coastal lakes, including healthier ecosystems, better water quality and an enhanced ability to cope with development pressures and climate change.

Due to a lack of consistent and reliable data, there are still many uncertainties in assessing the status of estuaries and coastal lakes and any associated trends. The capacity to monitor the status and condition of marine and coastal ecosystems is expected to be enhanced through the NSW Monitoring, Evaluation and Reporting Strategy of the natural resource management program.

The predicted impacts of climate change, particularly changes in storm inundation, intensity and frequency in the short term, and sea level rise and changes to salinity regimes in the longer term, will have a significant impact on coastal morphology, ecosystems and urban environments.

Expected climate change impacts should also be a significant consideration in the location of all future settlements to cater for an expanding population and development needs.

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