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 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.
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.
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.
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.
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.
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
The major population centres with their respective populations for the Sydney region are shown in Table P1.
Locality |
Population |
Sydney1 |
4,000,000 |
Wollongong1 |
293,503 |
Nowra1 |
34,957 |
Goulburn2 |
20,000 |
A number of small towns are interspersed throughout the rest of the region including Lithgow, Braidwood and Moss Vale.
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.
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
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
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.
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 |
|
- Total storage capacity is the sum of the accessible and dead storage capacities.
- Note that the pipeline to Goulburn was not complete during the 2011 Account.
- These volumes differ from the 2010 Account due to updated survey information.
- Blue Mountains storages include Medlow Reservoir, Greaves Creek Reservoir, Upper Cascade Reservoir, Middle Cascade Reservoir and Lower Cascade Reservoir.
- 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 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 P6. Map of the streamflow gauging stations used to develop flow charts
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.
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:
- Sydney Catchment Authority
- Lithgow City Council
- 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).
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.
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 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
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.
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.