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Melbourne: Region description

  • The region is home to over 75% of Victoria's population, most of which reside in the Melbourne metropolitan area.
  • Surface water is the main source of water for the region, primarily for urban water supply.
  • Desalinated water is available for urban supply as a climate-independent alternative water source.


Melbourne region map. Water use: 2.5 % of Australia's water use. Land use: 40% of the region used for grazing and agriculture. Ecosystems: 3 Ramsar-listed wetlands of ecological significance. Water resources: 95% sourced from surface water.

For further information about the region scroll down this page or click on the links below:


Geographic information

Yarra River, City of Melbourne (istock © anonymous)


General description

Area: 11,723 km²
Population: 4.53 million (Australian Bureau of Statistics [ABS] 2016a)


Map of main rivers and water catchments. The region is physically defined by the Bunyip, Maribyrnong, Werribee, and Yarra river catchments. A small part of the Moorabool River catchment is also in the southwest of the region encompassing the Western Treatment Plant service area. The city of Melbourne is located near the centre of the region along the Yarra River.
Figure R1 Contextual map of the Melbourne region


  • The Melbourne region is located in the southeast of mainland Australia and is home to more than 75% of Victoria's population.
  • The region is physically defined by the hydrological boundaries of the Bunyip, Yarra, Maribyrnong, and Werribee river catchments, as well as the 105 km² area beyond the Werribee River catchment serviced by the Melbourne Water Western Treatment Plant.
  • About 2.5% of Australia's water use occurs in the region, mostly from surface water for urban supply.


Land use

Map showing distribution and land use types. The city of Melbourne is located in the central part of the region along the coast. Urban land use is concentrated in the Melbourne metropolitan area. Primary land use is grazing. Areas of conservation and natural environments, as well as dryland agriculture, also occur throughout the region.
Figure R2 Land use in the Melbourne region


  • Urban centres make up 23% of the region's total area. The majority of the region's population resides in the Melbourne metropolitan area.
  • 34% of the region is for grazing, which is the dominant land use activity outside of the urban centres.
  • Two irrigation districts, Werribee and Bacchus Marsh, are located in the Werribee catchment and are important vegetable-growing areas for the region (see Irrigation districts).


Significant aquatic ecosystems

Map of Ramsar wetlands and nationally important wetlands. The 3 Ramsar-listed wetlands are the Edithvale–Seaford Wetlands in the central part of the region near the coast, Western Port Bay in the southeast, and Port Phillip Bay (Western Shoreline) and Bellarine Peninsula in the southwest. There are 5 nationally-important wetlands. Lerderderg River in the northwest, Werribee–Avalon Area and Point Cook and Laverton Saltworks in the southwest along the coast, Yarra River wetlands in the north, and Mud Islands wetlands within the Port Phillip Bay area in the southeast.
Figure R3 Significant wetlands within the Melbourne region


  • The region contains several wetland systems of international and national importance, including three Ramsar-listed wetlands at Edithvale–Seaford, Western Port Bay, and Western shoreline of Port Phillip Bay.
  • The region also contains five other wetlands of national importance: Lerderderg River, Point Cook and Laverton Saltworks, Werribee–Avalon area, Yarra River wetlands, and Mud Islands wetlands (which occur within Port Phillip Bay).
  • Further information can be found in the Directory of important wetlands in Australia.


Water resources

  • Surface water is the main source of water for the region and is primarily used for urban water supply.
  • Groundwater resources are mainly used to support agriculture in the region. Alternative climate-independent water sources for the region include desalinated water and recycled water.


Surface water


Map of 14 major water storages. Thomson Reservoir, located outside the region boundary to the east, is the region's largest water storage with a capacity of 1,068,000 ML. The remaining 13 storages are within the region boundary. Cardinia and Tarago are within the Bunyip River catchment. Greenvale, Yan Yean, Sugarloaf, Silvan, Maroondah, O'Shannassy, and Upper Yarra are within the Yarra River catchment. Rosslynne is within the Maribyrnong River catchment. Pykes Creek, Merrimu, and Melton are within the Werribee River catchments.
Figure R4 Surface water storages in the Melbourne region; capacity of each storage is also shown


  • Surface water storages are an important water source for both urban supply and irrigation scheme supply.
  • The largest storage in the region is the Thomson Reservoir, which represents 55% of the region's total storage capacity.
  • Thomson Reservoir, located outside the region boundary, supplies water to the Melbourne region's urban water system and, therefore, is considered a surface water asset in the account. Water is transferred from the reservoir to the Upper Yarra Reservoir via the Thomson–Yarra pipeline for distribution to the urban water supply system (see Figure R9).
  • For more information on storages, see the Bureau of Meteorology's Water storage website.


  • There are four main rivers within the region: Yarra, Bunyip, Maribyrnong, and Werribee rivers.
  • Limited diversions for consumptive use occurs directly from these rivers.


Map of key gauging stations. Werribee River at Werribee Diversion Weir, station ID 231204, is located in the southwest of the region. Maribyrnong River at Keilor, station ID 230105A, and Yarra River at Banksia Street Heidelberg, station ID 229135A, are near the centre of the region within 30 km of Melbourne. Bunyip River at Iona, station ID 228213, is in the region's southeast.
Figure R5 Key flow gauging stations along the Bunyip, Yarra, Maribyrnong, and Werribee rivers within the Melbourne region


Graph of mean monthly flows along the Werribee, Maribyrnong, Yarra, and Bunyip rivers, and mean monthly rainfall for the Melbourne region
Figure R6 Mean monthly flows along the Werribee, Maribyrnong, Yarra, and Bunyip rivers, and mean monthly rainfall for the Melbourne region


  • Seasonal flow characteristics of these rivers reflect the local rainfall pattern. Although relatively uniform throughout the year, higher rainfall and streamflow usually occurs during the winter–spring months (June–November); less rainfall and streamflow occurs in summer and autumn.
  • Flows in each of these rivers are affected by flow diversion structures, dam operations, and environmental releases.



  • The region's geology can be broadly split into two zones: the northern zone and the southern zone.
  • The geology of the northern zone is typically fractured bedrock and basalt; the coastal southern zone is unconsolidated sediments and basalts.


A simplified three-dimensional cross-section image of the Melbourne region's groundwater aquifers. The section is taken along the Werribee River in the southwestern part of the region. The region's aquifers are made up of several layered geological formations. The uppermost layer near the coast is the Quaternary sediments. Inland, extending the length of the river, is the Newer volcanic group, Brighton group, Fyansford formation, and Werribee formation (older volcanics). The Werribee formation sits above fresh basement bedrock, as well as a weathered bedrock layer in the upper reaches of the catchment.
Figure R7 Groundwater system within the northern and southern zones of the western part of the Melbourne region


  • Groundwater makes up less than 5% of the total water supplied to the Melbourne region.
  • Groundwater is mainly used to supplement surface water sources for high-value agriculture, including production of vegetables, fruits, wine grapes, flowers, and turf.
  • In the Melbourne region, there are six groundwater management areas and three water supply protection areas.


Map of groundwater management areas. There are 6 groundwater management areas in the region. Lancefield and Merrimu are in the northwest. Cut Paw Paw, Moorabbin, Frankston, and Nepean are along the coast in the central and southern parts of the region. There are also 3 water supply protection areas in the region. Deutgam is in the southwest. Wandin Yallock is in the northeast. Koo Wee Rup occupies a large area in the southeast.
Figure R8 Groundwater management areas within the Melbourne region


  • Permissible consumptive volumes, which is the maximum extraction limit, have been defined for each of the region's groundwater management and water supply protection areas.
  • Extraction also occurs in unincorporated areas, which is the rest of the region outside of these designated management areas.


Inter-region transfers

  • The Melbourne region's urban water supply is supplemented by surface water transferred from catchments outside of the region.
  • Melbourne's water authorities hold bulk entitlements for water from Lake Eildon (as part of the Goulburn and Murray system) and Silver and Wallaby creeks.


Map of the urban water system infrastructure. There are 2 wastewater treatment plants located within the region and 1 desalination plant located outside the region boundary to the southeast near Wonthaggi. There are also 4 major pipelines that deliver water from outside of the region to Melbourne's urban system. The Thompson–Yarra Pipeline connects the Thompson Reservoir northeast of the region to the Upper Yarra River. The North–South Pipeline connects the Goulburn River north of the region with Sugarloaf Reservoir. A pipeline connects Silver and Wallaby Creeks north of the region with Yan Yean Reservoir. A pipeline connects the Victorian Desalination Plant to the Cardinia Reservoir.
Figure R9 Melbourne's inter-regional water sources; wastewater treatment and desalination plant locations


  • Up to 66,000 ML of water may be diverted from Silver and Wallaby creeks into the Melbourne region's storages over a 3-year period.
  • From the Goulburn and Murray systems, up to 75,000 ML of water per year may be diverted (targeted long-term average volume) but only in times of critical human need or when needed for local fire-fighting.


Desalinated water

  • The Victorian Desalination Plant at Wonthaggi was declared operational in December 2012.
  • Melbourne's three retail water authorities have been granted bulk entitlements to desalinated water produced at the plant. The bulk entitlements allow these authorities to take a total average annual volume of up to 150,000 ML of desalinated water over any period of five consecutive years.
  • For further information on the Victorian Desalination Plant, refer to the Aquasure website.


Recycled water

  • There are two large wastewater treatment plants operated by Melbourne Water—Western Treatment Plant and Eastern Treatment Plant—that are the main source of recycled water in the region.
  • The primary uses of treated wastewater include horticulture and pasture irrigation, land and salinity management, and local irrigation (e.g. sport and recreational grounds).
  • About one third of the recycled water produced at the Western Treatment Plant is transferred to Lake Borrie Wetlands.



  • There are a number of stormwater harvesting schemes in operation throughout the Melbourne region; however, the volume of water currently harvested is small compared with recycled water.


Water systems

Urban water system

Map of urban retail and regional water authority service areas. There are 3 major water utilities in the Melbourne region: South East Water services the southeastern part of the region, Yarra Valley Water services the northeastern part of the region, and City West Water services the southwestern part of the region. Western Water is a regional water authority that services the western part of the region, including the towns of Bacchus Marsh, Melton, Sunbury and Gisborne. Central Highlands Water is also a regional water authority that services the western edge of the region, including the town of Ballan.
Figure R10 Urban retail and regional water authority service areas within the Melbourne region


  • Urban water supply in the Melbourne region is sourced primarily from surface water. Melbourne Water manages and operates the majority of surface water storages throughout the region and is responsible for supplying bulk water to the retail water authorities.
  • Three urban retail water authorities operate exclusively within the Melbourne region—South East Water, Yarra Valley Water, and City West Water—and they source all of their bulk water from Melbourne Water.
  • Western Water and Central Highlands Water are regional water authorities that also operate within the Melbourne region, but their service areas extend beyond the region boundary.


Irrigation scheme

Map of the irrigation areas. There are 2 gazetted irrigation areas in the western part of the region. The Werribee Irrigation District is located along the coast on the eastern side of the Werribee River. The Bacchus Marsh Irrigation District is located approximately 40 km northwest of the Werribee Irrigation District around the confluence of the Werribee and Lerderderg rivers.
Figure R11 The Werribee and Bacchus Marsh irrigation districts within the Melbourne region


  • Southern Rural Water operates two irrigation areas in the Melbourne region: the Werribee and Bacchus Marsh irrigation districts.
  • Both irrigation districts are important vegetable-growing areas for the region.
  • Water is primarily sourced from Pykes Creek, Merrimu Reservoir, and Melton Reservoir. Recycled water from the Western Treatment Plant is used to supplement the surface water supply.


Water management

Upper catchment area, Melbourne region (Bureau of Meteorology © Paul Feikema)


Surface water and groundwater management

Water legislation

  • Key legislation for managing water in the Melbourne region is Victoria's Water Act 1989 (the Water Act) and Victoria's Water Industry Act 1994 (the Water Industry Act).
  • The Water Act establishes the water entitlement framework for the allocation and management of the State's water resources. It sets out the functions, powers, and governance for Victoria's rural and regional water authorities and Melbourne Water.
  • Under the Water Act, the Victorian Government retains the overall right to use and control flows of Victoria's surface water and to issue entitlements. It also provides direction on groundwater management, such as licensing of bore construction and groundwater extraction.
  • The Water Industry Act governs how Government-owned retail and regional water authorities are licensed and operate.


Water management plans

  • Victoria's water entitlement and allocation framework takes a whole-of-system approach to water management in that it considers all water resources (surface water and groundwater) for both consumptive and environmental purposes at all phases of the water cycle.
  • The framework includes bulk entitlements authorising abstraction of water for consumptive use, urban and rural water authority drought response plans, urban water authority demand strategies, streamflow management plans, and groundwater management plans for water use in declared water supply protection areas.
  • Planning documents that influence water management in the Melbourne region include the Central region sustainable water strategy, the Melbourne Water System Strategy, and Water for a future-thriving Melbourne, which outline key strategies for managing the region's water resources and water needs into the future.


Environmental water management

  • The Victorian Environmental Water Holder is an independent statutory body responsible for making decisions on the best use of Victoria's environmental water entitlements.
  • There are currently three environmental entitlements in the Melbourne region: Consolidated Yarra Environmental Entitlement 2006 (revised in 2014), Tarago and Bunyip Rivers Environmental Entitlement 2009 (revised in 2014), and Werribee River Environmental Entitlement 2011.
  • The environment's share of water is called the 'Environmental Water Reserve', which is made up of actual entitlements for the environment, water set aside as part of conditions associated with consumptive water entitlements, and above—cap water left over after diversion limits are reached.
  • Information on environmental water for the 2019–20 year is available in the Cultural and environmental water note in 'Supporting information'.
  • Streamflow management plans are also in place within the Melbourne region, including Hoddles Creek, Little Yarra and Don rivers, Olinda Creek, Plenty River, Stringybark Creek, Pauls, Steels and Dixon creeks, and Woori Yallock Creek. These plans are managed by Melbourne Water.
  • Local management rules are available for several areas within the region that have a level of demand lower than water supply protection areas.


Cultural water management

  • The Victorian Aboriginal Heritage Act 2006 recognises the Aboriginal people as traditional owners of the land.
  • The waterways within the Melbourne region are important to cultural beliefs of traditional owners including the Wurundjeri, Wathaurung, and Bunurong people.
  • The Water Act recognises the right to take water under the Victorian Traditional Owner Settlement Act 2010. Members of a traditional owner group with a natural resource agreement can take and use water from a waterway or bore for traditional, non-commercial purposes.


Organisations responsible for water management

  • Organisations responsible for water management in the region are shown below.


Table R1 Organisations responsible for water management
OrganisationResponsibilityMajor storages operated within the region
Department of Environment, Land, Water, and Planning (Vic)
  • providing advice on policy, performance, and compliance to the Victorian Minister for Water
  • implementing Government policy
  • liaison between the Victorian Minister for Water and each water business.
Melbourne Water
  • supplying bulk water to:

– City West Water
– South East Water
– Yarra Valley Water
– Western Water
– water authorities outside the Melbourne region

  • providing sewerage collection and treatment to:

– City West Water
– South East Water
– Yarra Valley Water

  • operating the Eastern Treatment Plant and the Western Treatment Plant
  • supplying recycled water to a number of authorities for a variety of uses
  • operating the North–South and Thomson–Yarra pipelines
  • administering diversion licences for the Yarra and Maribyrnong catchments
  • undertaking waterways services, including flood and drainage management, waterway management, and water quality protection for the greater Melbourne metropolitan area.
  • Cardinia
  • Greenvale
  • Maroondah
  • O'Shannassy
  • Silvan
  • Sugarloaf
  • Tarago
  • Thomson
  • Upper Yarra
  • Yan Yean
Yarra Valley Water
  • providing water supply and sewerage services to 1.9 million people (over 800,000 residential, commercial and industrial customers) in the northern and eastern suburbs of Melbourne
  • operating nine local sewage treatment plants.
South East Water
  • providing water and sewerage services to 1.75 million people (approximately 750,000 residential, commercial and industrial customers) in the southeast of Melbourne
  • operating eight sewage treatment plants.
City West Water
  • providing water and sewerage services to over 1.0 million people (approximately 450,000 residential and business customers) in Melbourne's central business district and its inner and western suburbs
  • operating Altona sewage treatment plant.
Southern Rural Water
  • supplying water to irrigation districts at Bacchus Marsh and Werribee
  • supplying bulk water from Rosslynne, Pykes Creek, and Merrimu reservoirs to Western Water for supply to Myrniong, Melton, Macedon, Mt Macedon, Sunbury, Gisborne, and Bacchus Marsh
  • managing groundwater extraction licences in the Melbourne region
  • administering take-and-use licences (surface and groundwater) within the Bunyip catchment.
  • Melton
  • Merrimu
  • Pykes Creek
  • Rosslynne
Western Water
  • providing water, recycled water, and sewerage services to a population of over 150,000 in towns outside metropolitan Melbourne, and some that are outside the region
  • operating seven recycled water treatment plants
  • operating seven drinking water treatment plants.
Several minor storages
Gippsland Water
  • supplying water to the towns of Drouin and Neerim South in the east of the region under its entitlement to water within Tarago Reservoir and also supplying water to some urban areas outside the Melbourne region
  • operating a wastewater treatment plant at Drouin.
Central Highlands Water
  • providing urban supply to the towns of Blackwood and Ballan in the west of the region
  • operating a water treatment plant at Blackwood and a wastewater treatment plant at Ballan.
Port Phillip and Westernport Catchment Management Authority
  • coordinated catchment management within the Melbourne region
  • providing leadership to a range of stakeholder groups to deliver integrated catchment management and sustainability of the region's catchments. These groups include Melbourne Water, government agencies, local government, and community groups.


Water rights

Groundwater for farming, Melbourne region (Alison Pouliot © 2005)


Operating rules and constraints

Bulk entitlement conditions

  • A bulk entitlement is a legal right to take and use water granted under the Water Act 1989. Bulk entitlements can be held by water corporations, the Victorian Environmental Water Holder and other specified bodies defined in the Water Act.
  • Each bulk entitlement contains specific conditions governing the abstraction of water as set out in the Water Act 1989.
  • Typical bulk entitlement conditions include maximum annual and daily limits on the volume of water taken from a specific diversion point or water storage, and minimum passing flow requirements.
  • Conditions contained within each bulk entitlement are specific to that entitlement. All bulk entitlements are listed on the Victorian Water Register website.


Urban water restrictions

  • In times of severe water shortages, the urban water authorities in the Melbourne region can implement a regime of water restrictions ranging from Stage 1 (mild) to Stage 4 (severe). These restrictions are in accordance with their drought response plans.
  • The Victorian Minister for Water approves drought response plans, and water authorities are responsible for declaring water restrictions.
  • More information on urban water restrictions in the Melbourne region is available on the Bureau's Water Restrictions website.


Water licence restrictions


Water entitlements and other statutory water rights

  • The Water Act 1989 is the legislation that governs the way water entitlements are issued and allocated in the Melbourne region.
  • There is a range of entitlements that may be issued by the Victorian Minister for Water including bulk entitlements, environmental entitlements, water licences, and water shares. Other statutory rights to water are not formally issued but exist under the Water Act for domestic and stock purposes by virtue of an individual's private ownership of or access to land.
  • The Water Act allows individuals to abstract water for domestic and stock purposes from a range of surface water and groundwater sources without a licence.
  • Some rights to water exist under separate legislation. For example, under Victoria's Country Fire Authority Act 1958 firefighters have the right to use and control the delivery of water for firefighting purposes.
  • The irrigation supply system operated by Southern Rural Water in the Werribee and Bacchus Marsh irrigation districts is a declared system under the Water Act. This means that irrigators and private diverters are supplied water under a water share, a delivery share, or a water use licence.
  • Elsewhere in the Melbourne region, individual private diverters (including irrigators) abstract their water from streams under a licence issued under Section 51 of the Water Act.
  • Rights may be suspended, reduced, increased, or otherwise altered after a water shortage has been declared under Section 33AAA(2) of the Water Act.


Water allocations

  • Within the Melbourne region, only water shareholders in the Werribee and Bacchus Marsh irrigation districts are provided with a formal allocation against their entitlements.
  • Southern Rural Water determines a seasonal allocation for water shareholders in the irrigation districts based on water available in storage, estimated inflows, and carryover commitments.
  • No annual allocations are made for bulk entitlements or water licences. The volume of water available for bulk entitlement in any year is governed by the amount of water in their share of the water system and the conditions and obligations included in their entitlement. Water availability under water licences is directly related to streamflow rates.
  • More information on water shares and water allocations are available on the Victorian Department of Environment, Land, Water and Planning website.


Trades and water rights transfers

  • Within the Melbourne region, water entitlements and allocations associated with the Werribee irrigation system can be traded.
  • Trade may occur within zones or between trading zones within the Werribee system, as well as trade to and from the Werribee water system to other Victorian water systems. Currently, trade of allocation is permitted from the Thomson–Macalister system (outside the Melbourne region) to the Werribee system under special conditions.
  • More information on trading rules within and between water systems in Victoria are provided in the Trading Rules for Declared Water Systems.
  • Take-and-use licences in unregulated systems may also be traded, but only within the same surface water catchment or groundwater management area (see the Department of Environment, Land, Water and Planning website for more information).