A Summary Of Water Supplies In Australia (Stats & Trends Nationally, & By State)

This guide is a summary or snapshot of the water supply picture in Australia (based on 2016-17 levels).

We’ve put together some of the key stats, information and trends nationally and by state.

 

(NOTE – the information and figures below are based on the BOM 2016-17 report, and some stats and info from the ABS. You can access the full information at the links in the Sources section at the bottom of this post)

 

Summary – Water Supplies In Australia

Some of the most important facts and trends relating to Australia’s water supply:

Australia is a country with high climate and rainfall variability across the different regions of the country (and these factors can impact water supply from year to year)

Australia is the world’s second driest continent in terms of rainfall

Australia’s water storages might be divided into urban, and rural

A large % of Australia’s total accessible public water storage capacity is part of large scale hydro electric power generation schemes

Australia’s remaining water supplies are allocated 70% to agriculture, 20% to urban water supply, and 10% to other industries (such as mining, manufacturing, electricity and gas supply), and other uses (such as environmental water releases, cultural use, small scale hydro electric power generation, and flood mitigation)

One-fifth to one-third of the water used in Australia comes from groundwater, and cities mostly rely on ground water and surface water

Australia uses two climate independent water sources – desalination, and water recycling

Each State and city in Australia draws their water from different water sources in different % shares (surface, ground, desalinated, recycled and interregional transfers)

Australia’s recent annual water stress indicator numbers are far below the UN’s global indicator of water stress – meaning Australia is currently not a water stressed nation

Having said that, Perth is one of the places in Australia dealing with water scarcity related issues, but uses climate independent water sources such as desalination, as well as ground water replenishment schemes

Australia’s rainfall (annual rainfall, and stream flows into surface water) are some of the most variable in the world

Average annual rainfall has increased in Australia over the last century, but in some specific regions it has decreased significantly since 1960 (and events like the Millennium Drought can impact annual rainfall levels in certain States)

Water trading (water entitlement and allocation volumes) happens in parts of Australia, and within and between States

Environmental water release happens in different parts of Australia

Some of the water issues Australia deals with are stream and ground water salinity, and slow recharge rates of ground water (meaningful changes usually take 5 years or more) and generally low or average levels of ground water volume

The long-term average per capita renewable water resource for Australia is 43 kL/day

Australia has high per capita water resources because of the low population density

 

Water Supply Report Notes & Stats

Below are some of the main points to consider about Australia’s water supply nationally, and among the States and Territories (some of the information is paraphrased and summarised by us, so refer to the original report for the full direct text):

  • [Australia has highly variable rainfall and surface water flows]
  • [Water storage volume in ground water aquifers or bores doesn’t always increase after rainfall, whereas surface water generally does]
  • Total water extracted from Australia’s water supplies in 2016-17 – allocated to agricultural use at 70%, urban water supply at 20%, and other industries at 10%  
  • Water trading (water entitlement and allocation volumes) happens in [parts of Australia]
  • Environmental water releases [happen in different parts of Australia]
  • [Australia’s water stress indicator] values [of below 10%] are well below the initial water stress level of 25 per cent identified by the [UN]
  • Climate independent sources [used] in Australia include water desalination, and water recycling [recycled water use varies in the different urban centres (cities) year to year]
  • Australia has a certain level of renewable water resources
  • Streamflow salinity can be a problem in Australia
  • In many parts of Australia, soils, surface water and groundwater have a high salt content as a natural consequence of Australia’s dry climate and highly weathered landscape … Native vegetation clearing and dryland and irrigated agriculture have changed the water balance of catchments, increasing the mobilisation of salts from saline aquifers or shallow water tables into streams in many areas across Australia. 
  • Stream salinity concentrations determine the suitability of the water for various uses. About 60 per cent of Australia’s river and stream sites analysed in 2016–17 were on average in fresh condition (median salinity <500 mg/L), which is considered suitable for drinking.
  • Across many areas in Australia, salinity has been, and continues to be, managed, accounted for and monitored
  • Australia’s total accessible public storage capacity is just over 80 000 GL. Around 36 per cent is part of … large hydro-electric power generation schemes … The remainder is mostly used for direct water supply, including agricultural, urban and industrial uses, as well as for environmental releases.
  • Some storage capacity is available for flood mitigation and small-scale hydro-electric power generation.
  • Rural and urban systems have different amounts of total accessible water storage in Australia
  • Perth is one of the regions in Australia most affected by [a changing climate] … As global temperatures rise, the hydrological cycle intensifies and [there have been other changes as well]. Average annual rainfall has also decreased in Perth over the long term.
  • [Reduction in streamflow] can best be explained by changes in the catchment’s response to rainfall. These changes could arise from the decoupling of groundwater and surface water, and changes in land use. A detailed analysis of catchment rainfall runoff processes is needed to understand the causes of this decline.
  • … Global estimates put the volume of groundwater at around 13 times higher than the volume of all surface water, including lakes, rivers and wetlands. In Australia, this ratio is likely to be even higher given the arid nature of much of the continent. However, groundwater resources are not always suitable for large-scale or long-term use. Sustainable extraction of groundwater must balance against the recharge of the resource. Recharge rates are typically very small compared to the volumes in the aquifer. Groundwater is often saline, which reduces its suitability for use.
  • One-fifth to one-third of the water used in Australia comes from groundwater. It is extracted for agriculture, urban supply, industries and many other uses. Groundwater also supports aquatic ecosystems across the nation … The sustainability of groundwater systems is subject to the pressures of climate, extractions and population growth
  • Aquifers are naturally occurring three-dimensional, water bearing rocks and sediments; they vary by location and depth … [there are] upper, middle and lower aquifer groups.
  • Groundwater typically responds slowly to climatic changes, especially in comparison to surface water.
  • Meaningful change in groundwater levels usually happens over 5 years or more, rather than one year where seasonal variation can be more of a factor
  • Groundwater levels are influenced by several factors including climate, land use and extractions
  • Of 19,000 bores [that test groundwater levels], 70% of groundwater levels in upper aquifer bores were below average to average across most of Australia. The five-year trends in upper aquifer groundwater levels were mostly declining (51 per cent) or stable (39 per cent). Only 9 per cent of upper aquifer bores showed a rising trend. 
  • Similarly, groundwater levels of middle and lower aquifer bores were mainly below average to average with declining trends.
  • Higher rainfall tends to lead to higher groundwater levels because there is less groundwater extraction and more groundwater replenishment (as water is withdrawn from above surface water sources first)
  • Compared with 2015–16 data, the percentage of bores across Australia with below-average status decreased from 40 to 26 per cent in the upper aquifer, from 52 to 34 per cent in the middle aquifer, and from 41 to 30 per cent in the lower aquifer.
  • While the data shows a change towards rising groundwater levels, these results vary spatially [across different regions of Australia]
  • As a summary of groundwater levels across Australia in each State and Territory – The data show a shift in 2016–17 towards more bores with above-average status and fewer bores with a declining trend. 
  • Australia’s climate is highly variable, with low annual mean rainfall and high interannual variability.
  • Traditionally, Australian cities have relied on surface or groundwater sources to meet their water needs.
  • To improve the security of supply under a changing climate and growing population, climate-resilient sources such as seawater desalination and water recycling have been introduced
  • Australia has major, and smaller desalination plants across the major cities (the smaller plants provide water to industry and mines)
  • Recycled water from wastewater treatment plants is generally used year-round to take advantage of the consistent flows. Recycled water is mainly used for non-potable purposes, such as irrigation and toilet flushing. Industrial use of recycled water is also growing because water for potable use has become expensive, and there is growing awareness about fit-for-purpose use given scarcity of traditional water resources.
  • Recycled water can decrease during wet conditions during the irrigation season
  • Perth has it’s own ground water replenishment scheme going on, where treated wastewater is further purified to drinking water standards and then recharged into Perth’s confined aquifer. The water stored in the aquifer can be taken out later and supplied to the drinking water system after further treatment. 
  • Renewable water resources refer to water that is continuously renewed by the hydrological cycle, such as streams and reservoirs fed by runoff, and aquifers fed by groundwater recharge.
  • Australia’s long-term average rainfall is 461 mm, but only a small portion of this becomes renewable resources. On average, 9 per cent of this rainfall becomes runoff and about 2 per cent becomes recharge to groundwater … Based on this, the long-term average per capita renewable water resource for Australia is 43 kL/day, and the average for 2016–17 was 56 kL/day.
  • Although the total volume of fresh water available in Australia is less than in many other countries, Australia has high per capita water resources because of the low population density.
  • The regional distribution of resources is highly uneven, with abundant water resources in the northern regions compared with the middle part of the continent.
  • Also, large year-to-year rainfall variability, including seasonality, affects water availability in the Murray–Darling Basin. This high spatial and temporal variability in water distribution makes the water difficult to use.
  • Australia’s water made available consists of regulated surface water, unregulated surface water, and ground water
  • Australia’s water market [involves] the buying and selling of water entitlements and allocations [for trades and transfers between regions]
  • There are different reasons for price changes for water entitlements
  • Overall, entitlement prices tend to be less volatile than allocation prices because trading entitlement is driven by longer term changes, such as climate, structural changes to farming enterprises and long-term yield (that is, expected available water for the entitlement holder).
  • South Australia was the largest net importer of water through allocation trade, with a net import volume of 225 GL, which came mostly from Victoria (net import of 187 GL).
  • Trading of groundwater entitlements and allocations tends to be more limited than surface water trading.
  • Environmental water is water legally set aside to protect or restore the health of ecosystems fed by surface water or groundwater. This surface water is held in storages and is released to meet specific needs of the environment. There are two categories of environmental water: planned and held. Environmental water is largely held in surface water entitlements. Depending on the river operating rules, flow constraints and climatic conditions, environmental water can be used, held and carried over to the next year, or traded for equal or greater environmental benefit. The volume of available environmental water thus varies from year to year. 
  • Aboriginal people use water for cultural use too
  • The total volume of water abstractions for consumptive use is defined as all licensed water abstractions from rivers, storages, high-yielding aquifers and desalination plants that are not used for environmental or cultural purposes.
  • Water abstractions can be used for agriculture (70%), urban use (20%) and other industrial purposes (mining, manufacturing, electricity and gas supply, and other industry categories) (10%).
  • In all States and Territories except Western Australia and the Northern Territory, more surface water than groundwater was diverted to satisfy the demands from agriculture
  • Surface water was the main source of urban water supply in all major urban centres except Perth
  • Ground water extraction – With higher rainfall and easier access to surface water, farmers rely less on groundwater, which usually is more expensive to access.
  • Water availability vs use – Australia’s greatest water use occurs in regulated rural supply systems that source water from large storages. The amount of water extracted from these systems for consumptive and environmental use varies between years. The combined accessible storage volume in rural storages across the nation increased from 52 per cent of capacity in June 2016 to 78 per cent in June 2017. 
  • Australia has two main water supply systems – the Murray Darling Basin supply system, and the Northern supply system.
  • The total stored water vs used water differs for each system and area within each system.
  • But, generally, Australia has much more stored water than the amount of water used across the two systems.

 

Australia’s Total Accessible Public Water Storage Capacity

  • Australia’s total accessible public storage capacity is just over 80 000 GL.
  • Around 36 per cent is part of … large hydro-electric power generation schemes
  • The remainder is mostly used for direct water supply, including agricultural, urban and industrial uses, as well as for environmental releases
  • In 2016-17, usage volumes were 11, 010 GL for agricultural, 3, 130 GL for urban water supply, and 1, 530 GL for other industrial uses
  • Some storage capacity is available for flood mitigation and small-scale hydro-electric power generation.
  • The accessible storage volume for direct water supply purposes at the beginning of 2016–17 was at 57 per cent of capacity … this increased by 20 percentage points to 77 per cent of capacity by the end of 2016–17.
  • There are both urban water storages, and rural water storages

– bom.gov.au

 

Where Water For Agricultural Use Comes From In Australia (By Water Source)

In 2016/17:

  • 9, 180 GL was sourced from surface water and 1, 830 GL from groundwater

– bom.gov.au

 

Where Water For Urban Use Comes From In Australia, For Each State (By Water Source)

  • The total volume of water extracted by (urban) utilities in 2016–17 was 3, 130 GL.

– bom.gov.au

 

A general description of water sources might be:

  • Surface Water – comes from above ground lakes, rivers, wetlands
  • Ground Water – comes from underground aquifers, and makes up one fifth to one third of Australian water use
  • Stored Water
  • Seawater Desalination – comes from desalination plants (mainly larger plants in major cities, but also smaller plants for certain industries) and can be mixed with above ground supplies
  • Recycled Water – recycled water is internally sourced from existing water, and treated at waste water and recycled water plants
  • Interregional Transfers & Trades – the buying and selling of water entitlements and allocations within states, and between states

 

In 2016/17, this is how the major urban areas in Australia sourced their water:

Sydney

  • Surface Water – made up a large majority of total water use
  • Recycled Water – made up a much smaller amount of total water use, at about 6%

Melbourne

  • Surface Water – made up a large majority of total water use
  • Interregional Transfers – second largest % of total water use
  • Desalinated Water – made up about 11% of total water use
  • Recycled Water – made up a very small % of total water use

South East Queensland

  • Surface Water – made up a very large majority of total water use (97%)
  • Recycled Water – made up a much smaller % of total water use
  • Groundwater – made up about 2% of total water use
  • Desalinated Water – made up less that 1% of total water use

Perth

  • Desalinated Water – made up majority of total water use, along with groundwater
  • Groundwater – made up majority of total water use, along with desalinated water
  • Recycled Water – made up a very small % of total water use
  • Surface Water – made up a very small % of total water use

Adelaide

  • Surface Water – made up a very large majority of total water use, at 87%
  • Interregional Transfers – made up about 10 per cent of total water use, and came from the River Murray
  • Recycled Water – made up a very small % of total water use
  • Desalinated Water – made up only about 3% of total water use

Canberra

  • Surface Water – made up a large majority of total water use
  • Recycled Water – made up only about 9% of total water use

– bom.gov.au

 

You can see a full graph of water sources by city on page 51 of the BOM report.

 

Where Water For Use By Other Industries Comes From In Australia

  • Water abstractions can be used for agriculture (70%), urban use (20%) 
  • Other industrial purposes like mining, manufacturing, electricity and gas supply, and other industry categories make up 10%
  • The total water used for industrial purposes is estimated to be 1526 GL
  • Mining water use is estimated to be 661 GL, manufacturing to be 577 GL and electricity and gas to be 288 GL … Water use by other industries, especially service industries, is estimated as 1084 GL
  • Electricity generation mostly uses surface water, with many large power plants having a high security entitlement.

– bom.gov.au

 

Rainfall In Australia

Rainfall is important to a country’s water supplies as it has an effect on streamflows, and ultimately water levels in surface water and groundwater storage.

Rainfall averages can differ across a country depending on various factors such as the local climate, seasonal variability, and more.

 

  • Australia’s long term mean rainfall is 461 mm, while the 2016-17 mean rainfall was 28 per cent above this

– bom.gov.au

 

  • Australia’s average annual rainfall (measured 10 year periods) has actually increased from 1900, to 2010. 1900 to 1910 rainfall was 429mm, whilst 2000 to 2010 rainfall was 486mm
  • However, since 1960, there have been substantial decreases in rainfall over three relatively small, but economically and agriculturally important, regions: south-western Western Australia, Victoria (particularly southern Victoria) and the eastern coastal fringe (particularly south-eastern Queensland).

– abs.gov.au

 

  • Australia is the world’s second-driest continent (after Antarctica), with average (mean) annual rainfall below 600 millimetres (mm) [for] over 80% of the continent, and below 300 mm [for] over 50% [of the continent].

– abs.gov.au

 

Australia’s Climate

Climate also has the ability to impact a country’s water supply over the long term.

You can read more about national and local climate, and changes in the various climates over time in the abs.gov.au resource link below

 

Sources

1. http://www.bom.gov.au/water/waterinaustralia/files/Water-in-Australia-2016-17.pdf

2. http://www.bom.gov.au/water/waterinaustralia/

3. https://www.abs.gov.au/ausstats/[email protected]/Lookup/by%20Subject/1301.0~2012~Main%20Features~Australia’s%20climate~143

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