Sydney
Physical information

General description

Area: 30,800 km2 (Australian Bureau of Rural Science 2010).

Population: Over 4.6 million in 2010 (Australian Bureau of Statistics 2011).

The Sydney region is located on the southeast coast of New South Wales (NSW). It is the most populous metropolitan area in Australia and is home to 63% of the total NSW population. It spreads from Shoalhaven Heads in the south to Broken Bay in the north and from Lithgow and Goulburn to the west to the Pacific Ocean on the east coast as shown in Figures P1 and P2.


Figure P1. Location map of the Sydney region within Australia
Figure P1. Location map of the Sydney region within Australia


Figure P2. Contextual map of the Sydney region
Figure P2. Contextual map of the Sydney region


The Sydney region includes:

  • Shoalhaven River Catchment
  • Hawkesbury–Nepean River catchment
  • rivers of the Illawarra and metropolitan Sydney.

The Sydney region excludes the eastern subcatchments of the Hawkesbury–Nepean catchment starting from Mangrove Creek. These subcatchments were excluded in the NSW Draft Water Sharing Plan for the Greater Metropolitan Region Unregulated River Water Sources (NSW Office of Water 2012a) and have little contribution to the Sydney region water sources.

Shoalhaven River catchment

Catchment area: 7,300 km².
Catchment length: approximately 300 km.
The Shoalhaven River commences between the Gourock and Minuma ranges. The upstream catchment primarily contains rural areas and national parks while the downstream reach is an urban area.

Hawkesbury-Nepean River catchment

Catchment area: 22,000 km².
Catchment length: 339 km.
At the top of the catchment, the Wollondilly River confluences with the Coxs River at Lake Burragorang and flows as the Warragamba River until the Nepean River confluence. The river is named the Hawkesbury River after the confluence with the Gross River. The main tributaries of the Hawkesbury–Nepean River commence in rural areas and national parks. The river is tidal after its confluence with the Colo River.

Illawarra and metropolitan Sydney rivers

The rivers of the Illawarra and metropolitan Sydney are relatively small. The main Illawarra rivers are the Minnamurra River and Macquarie Rivulet. The main metropolitan Sydney Rivers are the Georges, Woronora and Hacking rivers in the south and the Parramatta River in the north.

General topography

The upstream reaches of the catchments in the Sydney region are hilly to mountainous country. The most downstream reaches are urbanised coastal areas with tidal rivers. Sydney City lies over Cumberland Plain, which is a relatively flat region to the south and west of the Sydney Harbour, and the Hornsby Plateau, which is a sandstone plateau mainly to the north of the harbour. The Hornsby Plateau is dissected by steep valleys.

Description of the region

Within the geographical boundaries described above, the region includes all of the water resources within or beneath the region excluding:

  • off-channel water, such as landscape catchment storages (also known as farm dams) and other off-channel storages used to harvest flood water or collect rain water, as it constitutes water that is already abstracted and no longer available for sharing
  • water stored in the landscape, such as soil moisture.

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

Land use

Major population centres within the region

The major population centres with their respective populations for the Sydney region are shown in Table P1.

 

Table P1. Major population centres for the Sydney region

Locality

Population

Sydney1

4,000,000

Wollongong1

293,503

Nowra1

34,957

Goulburn2

20,000

  1. Source: Australian Bureau of Statistics (2011)
  2. Source: Australian Bureau of Statistics (2007)

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

Land use activities

The major land use activities in the Sydney region are shown in Table P2 (Australian Bureau of Rural Science 2010). Figure P3 shows the distribution of these land uses.


Table P2. Major land use activities in the Sydney region

Land use activity

Area (km2)

Total area of the region (%)

Conservation and natural environments

17,125

56

Dryland agriculture

400

1

Forestry

1,375

4

Grazing

7,600

25

Irrigated agriculture

175

<1

Mining

75

<1

Other intensive uses

150

<1

Urban

3,425

11

Water

475

1

Total

30,800

100


Figure P3. Map of land use in the Sydney region
Figure P3. Map of land use in the Sydney region

Land use activities that are major water users in the region are (New South Wales Office of Water 2011b):
  • residential supplies in urban and rural areas
  • industry
  • mining
  • power generation
  • forestry
  • dairy
  • grazing
  • cereal cropping
  • horticulture.

Irrigated agriculture occupies less than 1% of land use in the region, and there are no major irrigation districts.


Significant aquatic ecosystems

The Sydney region contains the Towra Point Nature Reserve, a Ramsar-listed wetland, on the southern and eastern shores of Botany Bay. It also contains 25 nationally important wetlands, listed in the  Directory of important wetlands in Australia.

The Water Sharing Plan for the Greater Metropolitan Region 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 are known to host endangered ecological communities in the Sydney region. The Hawkesbury and Lower Nepean catchment contains Maroota Sands Swamp Forest and Sydney Freshwater Wetlands, both of which are highly sensitive to water abstraction (New South Wales Office of Water 2011b). 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 (New South Wales Office of Environment and Heritage 2011). Sydney Freshwater Wetlands also occur in the Illawarra catchment.

The Draft Water Sharing Plan for the Greater Metropolitan Region 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 also considered to be groundwater dependent.

Water resources

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

The other water sources for the region are:

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

Surface water

Major storages

There is an extensive storage and weir network to capture streamflows in many of the streams in the Sydney region. These storages provide water for urban centres, industries, power generation and many other minor uses. Table P3 shows a list of the major storages and their primary purpose. Opening and closing storage volumes for the 2011 Account are available in line item 1.1 Storages.

 

Table P3. Major storages in the Sydney region

Storage

Total storage capacity (ML)1

Dead storage volume (ML)

Purpose

Lake Lyell

34,192

2,083

Power generation from Mt Piper and Wallerawang power stations

Lake Wallace

4,004

1,798

Thomsons Creek

27,500

0

Pejar

9,000

90

Urban water supply to Goulburn Mulwaree Council area2

Sooley

6,250

300

Bamarang

3,800

100

Urban water supply to the Shoalhaven City Council area

Danjera

7,660

2,300

Cataract

97,370

180

Urban water supply to Sydney Metropolitan Region

Cordeaux

93,640

0

Avon

214,3603

67,660

Nepean

68,1003

0

Woronora

71,790

0

Lake Burragorang (Warragamba Reservoir)

2,031,000

4,000

Prospect

48,200

14,870

Wingecarribee

25,880

1,750

Fitzroy Falls

22,920

12,920

Lake Yarrunga (Tallowa Reservoir)

90,000

82,500

Blue Mountains4

2,8903

0

Bundanoon

1,170

Not available

Urban water supply to Wingecarribee Shire Council area

Medway

2,046

Not available

Flat Rock Creek
400
0
Urban water supply to Shoalhaven City Council
Farmers Creek No. 2
450
Not available
Urban water supply to Lithgow City Council

Total

2,863,622

190,5515

 

  1. Total storage capacity is the sum of the accessible and dead storage capacities.
  2. Note that the pipeline to Goulburn was not complete during the 2011 Account.
  3. These volumes differ from the 2010 Account due to updated survey information.
  4. Blue Mountains storages include Medlow Reservoir, Greaves Creek Reservoir, Upper Cascade Reservoir, Middle Cascade Reservoir and Lower Cascade Reservoir.
  5. Dead storage total volume only includes available information.

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

Water sourced from the supply network shown in Figure P4 is supplied to areas managed by Shoalhaven City Council, Wingecarribee Shire Council and Sydney Water.


Figure P4. Map of the operating infrastructure and the supply network for Sydney and surrounding areas covering reservoir capacity for over 95% of the region (source: Sydney Catchment Authority)
Figure P4. Map of the operating infrastructure and the supply network for Sydney and surrounding areas covering reservoir capacity for over 95% of the region (source: Sydney Catchment Authority)


Streamflow summary
There are three main river systems within the Sydney region being the Hawkesbury–Nepean River catchment, the Shoalhaven river catchment and the Illawarra catchment. The Illawarra catchment includes the metropolitan rivers of Sydney.

Figure P5 shows the mean monthly flows and mean monthly rainfall experienced in the Colo River within the Hawkesbury–Nepean catchment and the Shoalhaven River in the Shoalhaven River catchment. Figure P6 shows the location of these stations in the context of the Sydney region. Further information about monthly flows at these sites can be found in the Water overview. Information about climatic conditions in the region can be found in the Climate overview.


Figure P5. Graph of mean monthly flows in the Colo and Shoalhaven rivers and mean monthly rainfall in the Sydney region
Figure P5. Graph of mean monthly flows in the Colo and Shoalhaven rivers and mean monthly rainfall in the Sydney region


Figure P6. Map of the streamflow gauging stations used to develop flow charts
Figure P6. Map of the streamflow gauging stations used to develop flow charts


Inter-valley transfers

There are two inter-valley water transfer systems to and from the Sydney region:

  • import from the Fish River Water Supply Scheme
  • export to the Clyde River catchment.

In addition, there are inter-valley water transfers within the Sydney region linking the Shoalhaven catchment, the Hawkesbury–Nepean catchment and Sydney coastal catchments. These transfers are not distinguished in this water account as they occur within the region.

Import from the Fish River water supply scheme

The Fish River water supply scheme, which is located outside the Sydney region and managed by the New South Wales State Water Corporation (State Water), delivers water from Oberon Reservoir and Duckmaloi Weir to:

  • Oberon township
  • Lithgow villages
  • Sydney Catchment Authority, Blue Mountains storages
  • Delta Electricity
  • a number of minor customers.

State Water has a deemed water management licence for the Fish River water supply scheme and operates it in collaboration with the Customer Services Committee. The members of this Customer Services Committee include three organisations operating within the Sydney region:

  1. Sydney Catchment Authority
  2. Lithgow City Council
  3. Delta Electricity.

The volume of water supplied from the Fish River Water Supply Scheme (FRWSS) is based on water supply agreements between State Water and its customers.
The three organisations operating within the Sydney region with water entitlements from the FRWSS have a Maximum Annual Quantity (MAQ) entitlement as shown in Table P4 (sources: Delta Electricity, Lithgow City Council and Sydney Catchment Authority).

 

Table P4. Organisations operating within the Sydney region with water entitlements from the FRWSS

Organisation

Maximum Annual Quantity (ML)

Delta Electricity

8,184

Lithgow City Council (LCC)

1,778


Sydney Catchment Authority

3,650

Each organisation's MAQ is available for extraction in a given year if there are no restrictions. When the storage volume of Oberon Reservoir falls below 50%, the water allocation for major consumers is determined based on a restriction table. Restrictions vary with the storage level. Entitlement holders are allowed to carryover their unused allocation up to a maximum of 20% of the maximum annual quantity.

 

Export to the Clyde River catchment

The Shoalhaven City Council releases treated and untreated water from the Shoalhaven catchment to the Clyde River catchment, which is outside the Sydney region. Releases are made through Bamarang and Flat Rock reservoirs, respective water treatment plants and the supply network.

Groundwater

Groundwater rights in the Sydney region

Groundwater basic rights (19,700 ML) and entitlements (62,300 ML) are available in the Sydney region for a range of purposes including:

  • stock and domestic use
  • urban supplies by local water utilities
  • irrigation
  • commercial and industrial use.


Details can be found in the Water Sharing Plan for the Greater Metropolitan Region Groundwater Sources.

There is a 140 ML entitlement from three groundwater units: Goulburn Fractured Rock, Sydney Basin – Nepean Sandstone and Sydney Basin – Richmond Sandstone for urban water supplies in the Sydney region. There is no other groundwater entitlement conferred to management authorities to supplement centralised water supply to Sydney metropolitan area.

Other water resources and distribution systems

Recycled wastewater

A number of water utilities in the Sydney region manage the production of recycled water from wastewater as follows:

  • Sydney Water manages 13 recycled water plants in the Blue Mountains, Illawarra and Greater Sydney areas. Recycled water is released for commercial, industrial, residential, agricultural and other purposes.
  • Shoalhaven City Council produces recycled water at five wastewater treatment plants within the Sydney region for commercial, industrial, residential, agricultural and other uses.
  • Wingecarribee Shire Council and Goulburn Mulwaree Council produce small quantities of recycled water.
Desalinated water

Sydney's desalination plant at Kurnell commenced delivering water on 28 January 2010 (Sydney Water Corporation 2012a). It will operate at full production capacity when the total reservoir storage level is below 70%, and will continue until the level returns to 80%. The plant can supply 250 ML of water a day or up to 15% of greater Sydney's current water needs. As part of the plant commissioning process, it will operate continuously for two years until mid-2012 to ensure it meets planned performance and reliability targets. Thereafter, the plant is to be operated in accordance with agreed operating rules.