WATER SUPPLY IN SOUTH AUSTRALIA


INTRODUCTION

This article examines South Australia’s supply of water for the years 2000-01 and 2004-05 with reference to strategies for meeting Adelaide’s future water requirements.

The main source of data is the ABS publication Water Account, Australia, 2004-05 (cat. no. 4610.0) which provides water supply and use details for all states and territories for the periods 2000-01 and 2004-05. Supplementary data for South Australia were obtained from annual reports of SA Water and the Murray-Darling Basin Commission (MDBC). SA Water is the principal supplier of water to the Adelaide metropolitan area and country centres. The MDBC provides data relating to South Australia’s extraction of water from the River Murray.

The article is structured under the following headings (definitions were obtained from Water Account, Australia, 2004-05 (cat. no. 4610.0)).


Water extracted from the environment

(a) self-extracted water - water extracted directly from the environment for use; includes water from surface water (rivers, lakes, farm dams), groundwater (wells, bores and springs) and other water bodies (rainwater tanks).

(b) distributed water is a sub-set of self-extracted total. It is the water supplied to a user usually through a non-natural network (piped or open channel) and where an economic transaction has occurred for the exchange of this water. Water supplied by irrigation water providers via natural waterways and bores is considered to be distributed water.


Reuse and recycled water

(c) reuse water - drainage, waste or storm water supplied to a user without first being discharged to the environment. Reuse water is largely supplied by the wastewater (sewage) treatment plants of the Water supply, sewerage and drainage industry. This water may have been treated to some extent before supply. It excludes on-site recycling.

(d) recycled water - any water that is reused by the same organisation on-site after it has been used once. This includes on-farm reuse and the recycling of water in manufacturing processes.


Water distribution losses

Water that enters the water distribution system of a water provider that does not reach the end users/consumers. Water can be lost by seepage, leakage, evaporation (excluding evaporation from water storages), meter inaccuracies and theft.

Please refer to Figure 1 presented at the end of the article for a summary of water supply and use in the South Australian economy.


OVERVIEW

In 2004-05, 1,352 GL of water was extracted from the environment in South Australia. This was slightly down (by 2%) from the 1,380 GL extracted in 2000-01 (Table 1). Of the water extracted from the environment in 2004-05, 461 GL was supplied to users as distributed water. The volume of distributed water supplied in 2004-05 was down (by 11%) from the 517 GL supplied in 2000-01. This mirrored the trend across the country in which the supply of distributed water decreased by 12% between 2000-01 and 2004-05. The decrease in the supply of distributed water could be largely attributed to drier (drought) conditions in the State and the resultant water restrictions. For reuse water, a considerable increase (26%) was observed in the supply of reuse water in South Australia between 2000-01 and 2004-05, whereas a decrease (16%) was observed at the national level.

	SOUTH AUSTRALIA			AUSTRALIA
	2000-01 (GL)	2004-05 (GL)	% Change	2000-01 (GL)	2004-05 (GL)	% Change
Water Type
Self-extracted water	1,380	1,352	-2%	76,668	79,784	4%
Distributed water	517	461	-11%	12,934	11,337	-12%
Reuse water	18	22	26%	507	425	-16%

Source: Water Account, Australia 2004-05 (cat. no. 4610.0)


WATER EXTRACTED FROM THE ENVIRONMENT


Self-extracted water

In contrast to the national level, in which the volume of water extracted from the environment increased by 4% between 2000-01 and 2004-05, a decrease of 2% was observed in South Australia. For South Australia in 2000-01 and 2004-05, the two main industries extracting water from the environment were Agriculture and the Water supply, sewerage and drainage services industry (Table 2). In 2004-05, Agriculture extracted 60% percent of all water taken from the environment in South Australia (58% in 2000-01) followed by Water supply, sewerage and drainage services with 34% (38% in 2000-01). At the national level, the two main industries extracting water were Electricity and gas followed by Water supply, sewerage and drainage services, extracting 60,172 GL (75%) and 11,160 GL (14%) in 2004-05 respectively. The majority of water used by the Electricity and gas industry at the national level was used for hydro-electric power generation. No hydro-electric power generation is undertaken in South Australia.

	SOUTH AUSTRALIA			AUSTRALIA
	2000-01 (GL)	2004-05 (GL)	% Change	2000-01 (GL)	2004-05 (GL)	% Change
Water User
Agriculture	790	807	2%	7,532	6,582	-13%
Electricity and gas	0.6	0.3	-50%	54,677	60,172	10%
Water supply, sewerage and drainage services	517	461	-11%	12,915	11,160	-14%
Other (a)	72	84	16%	1,544	1,870	21%
Total	1,380	1,352	-2%	76,668	79,784	4%

(a) All other industries and households
Source: Water Account Australia, 2004-05 (cat. no. 4610.0)
Drought conditions were largely responsible for the decline in the total volume of water extracted from the environment in South Australia between 2000-01 and 2004-05. The impact in South Australia was mainly observed in the Water supply, sewerage and drainage services industry, where the volume of water decreased by 11% between 2000-01 and 2004-05 (Table 2).


Distributed water

The principal suppliers of distributed water in Australia are units categorised to the Water supply industry. In South Australia, almost all distributed water is supplied by this industry. The main water providers in South Australia are SA Water and irrigation providers (irrigation trusts). The water delivered by SA Water is obtained from reservoirs, the River Murray and groundwater (bores/well). The irrigation water providers distribute water to South Australian irrigators and other rural customers. They extract water from groundwater sources (e.g. the South East (SA) system) and rivers, principally the River Murray (e.g. the Central Irrigation Trust, Lower Murray system) (Australian National Committee on Irrigation and Drainage (ANCID) 2006).

In South Australia, 461 GL of water was distributed by water providers in 2004-05, which represented 34% of the water extracted from the environment. The majority (444 GL or 96%) of South Australia's distributed water supply was obtained from surface water (rivers, reservoirs, dams, lakes) and 17 GL (4%) was extracted from groundwater sources in 2004-05. Similarly, most (96%) of Australia's distributed water originated from surface water sources. Of the 448 GL of groundwater extracted in Australia for supply in 2004-05, 230 GL was extracted in Western Australia.

In South Australia, SA Water provided 251 GL of water to customers (SA Water 2005a), accounting for 54% of the State's distributed water deliveries in 2004-05. Irrigation water providers accounted for the remaining 44%.


SA Water

About 50% (126 GL) of the water provided by SA Water in 2004-05 was obtained from reservoirs; 44% (111 GL) was extracted from the River Murray; and groundwater (bores/wells) extractions provided 6% (SA Water 2005a). Graph 1 shows the proportions of water extracted by SA Water from the River Murray and reservoirs and groundwater sources for the years 2000-01 to 2004-05. The year 2002-03 was a drought year in South Australia, and it is notable that 72% (203 GL) of SA Water's supply was sourced from the River Murray for that period (SA Water 2003a).

In 2003, Adelaide residents faced the first compulsory water restrictions imposed since the opening of the Mannum to Adelaide pipeline in 1955 (Water Proofing Adelaide (WPA) 2005a). This was part of the South Australian Government’s Water Proofing Adelaide (WPA) Strategy that aimed to ensure sufficient mains water supplies could meet essential water demand during major droughts without extreme water restrictions.



Irrigation water providers

South Australian irrigation water providers distributed 204 GL of water to South Australian irrigators and other rural customers in 2004-05. This represented 44% of South Australia's distributed water supply and 0.3% of the corresponding national total (6,637 GL). Water was mainly extracted from groundwater sources (e.g. the South East (SA) system) and rivers, principally the River Murray (e.g. the Central Irrigation Trust, Lower Murray system) (ANCID 2006).


REUSE WATER


Reuse of wastewater

Between 1996-97 and 2004-05 the supply of reuse water in South Australia more than doubled, from 8 GL to 22 GL; nationally the increase more than trebled, from 134 GL to 425 GL. In 2004-05, almost all (21 GL out of 22 GL) of South Australia's reuse water was supplied by the Water supply, sewerage and drainage industry, with 20 GL derived from wastewater treatment. SA Water operated 24 wastewater treatment plants in 2004-05, delivering 20 GL to irrigators (both for agriculture and community resources such as parks, sporting grounds) in the Adelaide Metropolitan area and 1.4 GL to country users (SA Water 2005b).

Graph 2 shows the volume of annual reuse water supplied by SA Water's metropolitan area wastewater treatment plants for the period 2001-02 to 2004-05 (data were not available for 2000-01). Between 2001-02 and 2004-05 the volume of water supplied as reuse increased from 14 GL per annum to 20 GL, an increase of 41%. In 2004-05, the 20 GL of reused wastewater represented 21% of the annual effluent production; in 2001-02 this proportion was 15%.


It is estimated that 70 GL of the 90 GL of wastewater that is generated in Adelaide each year is discharged into the sea. About a half (or more) of the fresh water consumed by Adelaide households is returned to sewers from toilets, showers and washing machines (WPA 2005a). One desired key outcome of the WPA Strategy is for Adelaide’s use of recycled wastewater to grow from the 14 GL per annum of 2001-02 to 30 GL per annum by 2025. This could be achieved by expanding or developing further large-scale recycled water schemes.

The WPA Strategy asserts that the planned increase in the use of recycled water by the main consumers (irrigators) would reduce the strain on Adelaide's groundwater supplies given that most of the groundwater resources in and around Adelaide are either fully allocated, or even over-allocated (WPA 2005a).


Stormwater and rainwater

In 2005, the capture and use of stormwater (and rainwater) was estimated at between 3 and 5 GL per year (WPA 2005a). Stormwater recycling schemes are currently operated by the City of Salisbury and the Morphettville Racecourse. The key outcome for stormwater/rainwater use is for the utilisation of 20 GL per year by 2025. Part of the strategy for achieving this goal is the requirement for all new homes in South Australia (from July 2006) to have a rainwater tank plumbed into the house for some domestic uses. At March 2004, South Australia had the highest proportion (48%) of households with rainwater tanks compared to the Australian average of 17%. It should be noted that in the publication Water Account, Australia, 2004-05 (cat. no. 4610.0), use of rainwater by households is included with self-extracted water. The actual volume of rainwater used by households is difficult to quantify and has not been separately reported.

SA Water is a partner in the Mawson Lakes residential third pipe scheme where recycled wastewater from the Bolivar wastewater Treatment Plant is combined with captured stormwater from the Salisbury area to provide an alternative supply for irrigation of gardens and open space areas, as well as toilet flushing (SA Water 2005b).


WATER DISTRIBUTION LOSSES

It was estimated that, in 2004-05, about 15% (71 GL) of South Australia's distributed water was lost through the supply infrastructure (underground pipe leakages, burst mains, evaporation from open channels), theft and customer meter errors. The greatest losses occurred in the distribution of water to irrigation/rural water users, where 40 GL, or 20% of the supply was lost. Nationally, the total losses were estimated to be 2,022 GL (18%) of distributed water, with irrigation/rural losses of 1,500 GL (23% of this supply).

SA Water has introduced a leakage reduction program and the State's leakage rate is recognised as one of the lowest in the world (WPA 2005a). Water lost by evaporation from reservoirs in 2002-03 was estimated at 26 GL; as part of the WPA Strategy, emerging technologies (including chemical films) will be assessed as agents for reducing evaporative losses from reservoirs. SA Water is also undertaking a water meter replacement program to reduce leakage and to provide better water usage data for householders and SA Water.

Various programs are currently in place to manage, conserve and develop South Australia's water resource. Strategies for meeting the future water requirements of Adelaide and its environs are outlined in the South Australian Government’s 20-year water plan Water Proofing Adelaide - A Thirst for Change 2005-2025 (PDF (2 MB)). This plan was launched in October 2003 in recognition of the need to address challenges to Adelaide’s water supply and aims at management of existing water resources, responsible water use, and the development of additional water supplies to ensure adequate supplies to satisfy a growing population and economic development.

In partnership with other state governments, South Australia has also committed to the Department of the Environment, Water and the Arts' Living Murray initiative with a view to securing 500 GL of water to improve the health of the Murray-Darling Basin by 2009. The River Murray Levy, which was introduced by the South Australian Government in 2003, is to be used for programs to improve the health of the River Murray; for example, salt interception schemes and permanent return of water to the River.

Coupled with the management measures will be State Government strategies to make further gains in water use efficiency by households, industrial and commercial users, agricultural users, and in public facilities (community purposes) such as parks, gardens and ovals. Key targets include reducing per capita household water use by 22% by 2025; reducing industrial and commercial use of water by 10%; and reducing community purposes mains water use by 12%. Under the State Government's Water Allocation Plan, irrigators are expected to raise their efficiency of water use to 85%.




REFERENCES

Australian Bureau of Statistics (ABS) 2006, Water Account for Australia 2004-05, (cat no. 4610.0), viewed 1 February 2008

Australian National Committee on Irrigation and Drainage 2006, Australian Irrigation Water Provider Benchmarking Data Report for 2004-2005, Australian National Committee on Irrigation and Drainage, Canberra

Murray-Darling Basin Commission (MDBC) 2002, Water Audit Monitoring Report 2000-01 Report of the Murray-Darling Basin Commission on the Cap on Diversions,Murray-Darling Basin Commission, Canberra, PDF (1.4 MB), viewed 2 February 2008

Murray-Darling Basin Commission (MDBC) 2003, Water Audit Monitoring Report 2001-02 Report of the Murray-Darling Basin Commission on the Cap on Diversions,Murray-Darling Basin Commission, Canberra, PDF (1.3 MB), viewed 2 February 2008

Murray-Darling Basin Commission (MDBC) 2004, Water Audit Monitoring Report 2002-03 Report of the Murray-Darling Basin Commission on the Cap on Diversions,Murray-Darling Basin Commission, Canberra, PDF (1.1 MB), viewed 2 February 2008

Murray-Darling Basin Commission (MDBC) 2005, Water Audit Monitoring Report 2003-04 Report of the Murray-Darling Basin Commission on the Cap on Diversions,Murray-Darling Basin Commission, Canberra, PDF (1.2 MB), viewed 2 February 2008

Murray-Darling Basin Commission (MDBC) 2006, Water Audit Monitoring Report 2004-05 Report of the Murray-Darling Basin Commission on the Cap on Diversions,Murray-Darling Basin Commission, Canberra, PDF (1.3 MB), viewed 2 February 2008

SA Water 2001, Annual Report 2000-01,SA Water, Adelaide

SA Water 2002, Annual Report 2001-02,SA Water, Adelaide

SA Water 2003a, Annual Report 2002-03,SA Water, Adelaide, PDF (3.5MB), viewed 1 February 2008

SA Water 2003b, 2003 Sustainability Report,SA Water, Adelaide, PDF (1.7MB), viewed 1 February 2008

SA Water 2004, Annual Report 2003-04,SA Water, Adelaide, PDF (4.1 MB), viewed 1 February 2008

SA Water 2005a, Annual Report 2004-05,SA Water, Adelaide, PDF (4.1MB), viewed 1 February 2008

SA Water 2005b, 2004-05 Sustainability Report,SA Water, Adelaide, PDF (2.6MB), viewed 1 February 2008

Water Proofing Adelaide 2005a, Water Proofing Adelaide: A thirst for change 2005-2025,Water Proofing Adelaide, Adelaide, PDF (2 MB), viewed 1 February 2008

Water Proofing Adelaide 2005b, A thirst for change: Water Proofing Adelaide 2005-2025 A blueprint for the management, conservation and development of Adelaide's water resources to 2025, Water Proofing Adelaide, Adelaide, PDF (1.2 MB), viewed 2 February 2008