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National Water Account 2015

Sydney: Physical information

Warragamba Dam, New South Wales (iStock © Kokkai Ng)

General description

Area: 30,800 km2 

Population: 4.71 million (Australian Bureau of Statistics [ABS] 2011)

The Sydney region is located on the coast of New South Wales, as shown in Figure C1. It includes the city of Sydney, Australia's most populous city, and is home to 63% of New South Wales' total population. The region spreads from Nowra in the south to Broken Bay in the north; from Lithgow and Goulburn to the west; and to the Pacific Ocean on the east coast (Figure C2).

 

Figure C1 The Sydney region within Australia
Figure C1 The Sydney region within Australia

 

Figure C2 Contextual map of the Sydney region
Figure C2 Contextual map of the Sydney region

 

Region definition

The Sydney region is physically defined by the boundaries of the following catchment areas, from north to south as shown in Figure C2.

  • Hawkesbury–Nepean River catchment: Catchment area is 22,000 km². At the top of this catchment, the Wollondilly River joins with the Coxs River at Lake Burragorang and flows as the Warragamba River until the Nepean River confluence. From this point, the Nepean River flows through until its confluence with Grose River, after which it is named the Hawkesbury River. The main tributaries of the Hawkesbury–Nepean River commence in rural areas and national parks. The Hawkesbury River is tidal the full extent of its length from the confluence with the Grose River.
  • Shoalhaven River catchment: Catchment area is 7,300 km². The Shoalhaven River commences between the Gourock and Minuma ranges. The upstream catchment is primarily rural areas and national parks, while the downstream reach contains small urban areas surrounded by rural areas.
  • Sydney coast–Georges River and Illawarra catchment: The rivers of metropolitan Sydney and Illawarra catchment are relatively small. The main metropolitan Sydney rivers are the Georges, Woronora and Hacking rivers in the south and the Parramatta River in the north. The main Illawarra rivers are the Minnamurra River and Macquarie Rivulet.

The Sydney region excludes the northeastern subcatchments of the Hawkesbury–Nepean catchment starting from Mangrove Creek. These subcatchments were excluded in the Water Sharing Plan for the Greater Metropolitan Region Unregulated River Water Sources (NSW Office of Water 2011a) and make little contribution to the region's water sources.

The region includes water stored in and transactions related to:

  • surface water storages in the region
  • rivers within the region
  • water held in storages, pipes and infrastructure as part of urban water supply and wastewater systems.

The region excludes water stored in:

  • off-channel water storages and rainwater tanks, such as farm dams and private commercial water storages used to harvest runoff or collect rainwater
  • the landscape, such as soil moisture.

For more information regarding items in this report, please refer to the Water accounting policies.

 

Land use

The major population centres with their respective populations for the Sydney region (ABS 2011) are:

  • Sydney: 3,909,000
  • Wollongong: 246,000
  • Nowra: 28,000
  • Goulburn: 21,000.

A number of small towns are interspersed throughout the rest of the region including Lithgow, Braidwood and Moss Vale.

The major land uses within the Sydney region are shown in Figure C3 (Australian Bureau of Agricultural and Resource Economics and Sciences 2014). A more detailed breakdown of land use type and area for the Sydney region is provided in this table.

 

Figure C3 Land use in the Sydney region
Figure C3 Land use in the Sydney region
 

 

Significant aquatic ecosystems

The Sydney region includes the Towra Point Nature Reserve, an estuarine system and a designated Ramsar wetland, on the southern and eastern shores of Botany Bay. There are also 25 nationally important wetlands listed in the directory of important wetlands in Australia (Department of the Environment 2001).

The Water Sharing Plan for Greater Metropolitan Region Unregulated River Water Sources (NSW Office of Water 2011a) identifies 29 river management zones that were assessed as having high instream values. These were identified according to a number of criteria, including the presence of threatened species or ecological communities that are likely to be sensitive to water abstraction.

Several water sources in the Sydney region are known to host endangered ecological communities. The Hawkesbury–Nepean catchment contains Maroota Sands Swamp Forest and Sydney freshwater wetlands, both of which are highly sensitive to nearby water abstraction. Sydney freshwater wetlands is the name given to the plant community characterised by the assemblage of specific species restricted to freshwater swamps in swales and depressions on sand dunes and low-nutrient sandplain sites in coastal areas (NSW Office of Environment and Heritage 2011). Sydney freshwater wetlands also occur in the Illawarra catchment.

The Water Sharing Plan for Greater Metropolitan Region Unregulated River Water Sources also identifies high priority groundwater dependent ecosystems that include wetlands, karst systems and endangered ecological communities. There are 21 karst systems (including the major cave systems of Jenolan, Wombeyan and Bungonia) and five vegetation communities that are also considered to be groundwater dependent.

Figure C4 shows the significant wetlands of the Sydney region.

 

 Figure C4 Significant wetlands of the Sydney region
Figure C4 Significant wetlands of the Sydney region

 

Significant Indigenous cultural places and practices

The Kangaroo River is an important area for the Nowra and Illawarra local Aboriginal land councils. The Kangaroo River has been recognised as an area of cultural significance as well as a source of food for Aboriginal communities. The Water Sharing Plan for the Kangaroo River Water Source 2003 (NSW Office of Water 2014) provides for native title rights as basic landholder rights.

 

Water resources

Surface water is the main water source in the Sydney region. The region's surface water resources were developed to meet the Sydney's water needs. The reservoir capacity in the Sydney region is one of the largest in the world per head of population (NSW Office of Water 2010). This capacity is needed due to the region's irregular interannual rainfall runoff patterns and the resultant challenges this poses for a reliable water supply. The flows from a number of main rivers are heavily controlled by dams and numerous major weirs.

The other water sources for the region are:

  • groundwater
  • desalinated water supply from the Kurnell desalination plant to the Sydney metropolitan area
  • recycled water supply by Sydney Water Corporation (Sydney Water) and several other local councils
  • inter-basin transfers to the region from the Fish River Water Supply Scheme, a tributary of Macquarie River.

 

Surface water

Rivers

There are three main river systems within the Sydney region:

  • Hawkesbury–Nepean River catchment
  • Shoalhaven River catchment
  • Illawarra and metropolitan Sydney catchments.

Figure C5 shows the mean monthly flows and mean monthly rainfall experienced in the Colo River (within the Hawkesbury–Nepean catchment) and the Shoalhaven River. Figure C6 shows the location of selected key gauging stations along these main rivers. Further information about climatic conditions in the region and monthly flows at these stations can be found in Climate and water overview.

 


Figure C5 Mean monthly flows along the Colo and Shoalhaven rivers and mean monthly rainfall for the Sydney region

Figure C5 Mean monthly flows along the Colo and Shoalhaven rivers and mean monthly rainfall for the Sydney region

 

 

Figure C6 Streamflow gauging stations along the main rivers within the Sydney region
Figure C6 Streamflow gauging stations along the main rivers within the Sydney region


Major storages

There is an extensive storage and weir network for capturing streamflows in the Sydney region. The region's largest storage, Lake Burragorang (Warragamba), with a capacity of 2,031,000 ML, represents 70% of the storage capacity of Sydney region's major storages. These storages provide water for urban centres, industries, power generation and many other minor uses. A map of the major storages within the Sydney region is provided in Figure C7.


Figure C7 Major storages in the Sydney region; capacity of each storage is also shown

 Figure C7 Major storages in the Sydney region; capacity of each storage is also shown


Water from the Shoalhaven catchment is able to be diverted to the Hawkesbury–Nepean catchment through the Lake Yarrunga (Tallowa), Bendeela Pondage and Fitzroy Falls storages.

A large part of the supply network is managed by WaterNSW, while other water supplies in the area are managed by Shoalhaven City Council, Wingecarribee Shire Council and Sydney Water. More information on the WaterNSW supply network is available from the WaterNSW website.

 

Intervalley transfers

The Fish River Water Supply Scheme, which is located outside the Sydney region and managed by WaterNSW, delivers water from the Oberon reservoir and Duckmaloi weir to the following major customers:

  • Oberon township
  • Lithgow villages
  • WaterNSW, Blue Mountains storages
  • Energy Australia.

The Oberon township is outside the Sydney region boundaries so has not been included in the region's account.

Further, there are intervalley water transfers within the Sydney region linking the Shoalhaven catchment, the Hawkesbury–Nepean catchment and the Sydney coastal catchments. These transfers are not accounted for in this water account as they occur within the region and within the surface water store.

 

Groundwater

Groundwater is not a major water source in the Sydney region. The Sydney region's groundwater resources are mainly utilised for irrigation and industrial purposes. There are 13 groundwater sources identified in the region. A groundwater source as defined in the Water Sharing Plan for Greater Metropolitan Region Groundwater Sources 2011 (NSW Office of Water 2011b) is one or more places where water naturally occurs below the surface of the ground. 

These groundwater sources are grouped into three types, as follows:

1. Fractured rock  

  • Goulburn
  • Coxs River.

2. Porous rock

  • Sydney Basin South
  • Sydney Basin Richmond
  • Sydney Basin North
  • Sydney Basin Nepean
  • Sydney Basin Coxs River
  • Sydney Central Basin
  • Sydney Basin Blue Mountains.

3. Coastal sands, tertiary sands and alluvial

  • Metropolitan Coastal Sands
  • Maroota Tertiary Sands
  • Botany Sandbeds
  • Hawkesbury Alluvium.


The Water Sharing Plan for the Greater Metropolitan Region Groundwater Sources: Background document (NSW Office of Water 2011c) provides further details about these groundwater sources. For management purposes, these groundwater sources have been sorted into groundwater management units. Figure C8 shows a map of the groundwater management units in the Sydney region. 

Figure C8 Groundwater management units within the Sydney region
Figure C8 Groundwater management units within the Sydney region

 

Desalinated water

Sydney's desalination plant at Kurnell commenced delivering water on 28 January 2010 (Sydney Water Corporation 2012). It operates at full production capacity when the WaterNSW's total operating storage capacity (2,581,749 ML) falls below 70% and continues to operate until the level returns to 80%. The plant can supply 250 ML of water a day, equivalent to 15% of greater Sydney's current water needs. As part of the plant's commissioning process, it operated continuously for two years until June 2012 to ensure it met planned performance and reliability targets. Since June 2012, the plant has been taken offline and would be brought back online within eight months if the total WaterNSW (formerly Sydney Catchment Authority) storage system fell below 70% of capacity.

 

Other water resources and systems

Recycled wastewater

The major water utilities managing the production of recycled water from wastewater are as follows:

  • Sydney Water Corporation manages 14 recycled water plants across the Blue Mountains, Illawarra, and Greater Sydney areas. Recycled water is distributed for residential, commercial, industrial, agricultural and other purposes.
  • Shoalhaven City Council produces recycled water at nine wastewater treatment plants (WWTP) for commercial, industrial, agricultural and other uses. Among them, Bomederry WWTP, Culburra WWTP, Nowra WWTP and Shoalhaven Heads WWTP are located in Sydney region.
  • Wingecarribee Shire Council, Lithgow City Council and Goulburn Mulwaree Council produce small quantities of recycled water for commercial, industrial, agricultural and other uses.

 

Fish River Water Supply Scheme

WaterNSW1 (formerly State Water) has a water management licence for the Fish River Water Supply Scheme and operates it in collaboration with the Fish River Customer Council. The members of this council are as follows:

  • WaterNSW
  • Lithgow City Council
  • Oberon Shire Council
  • Energy Australia.

The Oberon Shire Council has not been included in the Sydney account because it falls outside of the region boundaries.

More information on the scheme is available under Water rights.

1At the start of 2015 WaterNSW was formed by merging the Sydney Catchment Authority and State Water Corporation.