Water resource development

2016

After a few years of moderate change in urban water demand, recent years (2013–14) have seen an increase in water demand from larger urban water-consuming areas across Australia. National Water Account figures for Melbourne, Sydney, Brisbane and Perth generally saw increases in water abstraction, urban claim and household water supply.

For Sydney, the urban water supply in 2013–14 was 557,820 megalitres (ML), a marginal increase from 543,311 ML in 2012–13 and 502,296 ML in 2011–12 (Figure WAT6; Table WAT2). In the latter 2 years, this demand was supplied primarily from surface-water sources, whereas in 2010–11 and 2011–12, some 12–15 per cent was supplied by the Kurnell desalination plant.

For Melbourne, south-east Queensland (including Brisbane) and Perth, similar moderate growth is seen in urban water supply (Table WAT2; BoM 2013a, 2014b, 2015b). This growth reflects the combined effects of population and per-person consumption.

At June 2015, an estimated 4.53 million people were residing in Greater Melbourne, an increase of 91,600 from June 2014. This was the largest growth of all greater capital cities in Australia (Table WAT3). The Australian Bureau of Statistics reported that, for 2014–15:

Melbourne’s population grew by 2.1 per cent in 2014–15, down slightly from 2.2 per cent last year, but still higher than the next-fastest growing capital, Darwin (1.9 per cent). Perth, which has been one of the fastest-growing capital cities since the mid-2000s, grew by 1.6 per cent in 2014–15 (down from 1.9 per cent last year) and now sits equal fourth with Brisbane, behind Sydney (1.7 per cent). (ABS 2015b)

Urban water consumption is reported in a series of national performance reports now published by the Bureau of Meteorology. The 2013–14 report detailed average residential water supplied (kilolitres per property) that, in general, showed a change from a downwards or steady trend at the end of the millennium drought to an increasing trend in the 4 years to 2013–14 (Figure WAT7).

 

Table WAT2 Urban water supply, Sydney, Melbourne, south-east Queensland (including Brisbane) and Perth, 2011–12 to 2014–15

Area or capital city

2011–12

(ML)

2012–13

(ML)

2013–14

(ML)

2014–15

(ML)

Sydney

502,296

543,311

557,820

543,588

Melbourne

374,198

408,878

415,436

420,391

South-east Queensland (including Brisbane)

243,213

251,897

261,247

267,792

Perth

283,027

284,058

289,114

291,026

ML = megalitres

 

Table WAT3 Estimated resident population of capital cities, 30 June 2015

Greater capital city statistical area

Estimated resident population
at 30 June 2015

Change 2014–15 (no.)

Change 2014–15 (%)

Greater Sydney

4,921,000

83,300

1.7

Greater Melbourne

4,529,500

91,600

2.1

Greater Brisbane

2,308,700

35,200

1.6

Greater Perth

2,039,200

31,100

1.6

Greater Adelaide

1,316,800

12,100

0.9

Australian Capital Territory

390,700

5,400

1.4

Greater Hobart

221,000

1,700

0.8

Greater Darwin

142,300

2,600

1.9

Source: ABS (2015b)

 

Urban demand is only one of the demands for water arising from the twin drivers of population and economic growth. Agriculture consumes around 7000–13,000 GL per year, depending on the water available from climate and storage. This equates to some 50–65 per cent of Australian water consumption (ABS 2014a, ABS 2015a). Recreational pressures occasionally come into play for surface-water resources, such as in maintaining high water levels during summer holiday periods, although these pressures are minor compared with the overall balance of water moving through managed systems.

As noted in SoE 2011, in recent decades, meeting water demand has shifted away from a large focus on building new water storage infrastructure. New approaches combine development of dams and climate-resilient water sources, such as desalination plants, with changes in the management of water, such as demand management (reducing per-person consumption) and increased water use efficiency. Note that the latter can be achieved through both infrastructure and management actions.

The annual production capacity of the 360 desalination and recycled water plants captured in the Bureau of Meteorology’s climate-resilient water sources dataset is more than 1821 GL, with actual production in 2012–13 exceeding 440 GL or approximately 25 per cent of estimated capacity. More than two-thirds of this was for urban use. Across Australia, the production capacity for climate-resilient sources has risen by more than 360 GL since 2011, including large desalination plants at Dalyston, Victoria (162 GL), and Binningup, Western Australia (111 GL).

Dams

There has been a range of levels of development of dams during recent years. Although states and territories generally have good processes for approval and licensing of dam construction, public reporting of construction is less clear. One of the larger dam infrastructure projects completed since 2011 is the Cotter Dam enlargement in the Australian Capital Territory, which, when completed in 2013, increased the reservoir capacity from 4.0 to 79.4 GL, with an accessible volume of 76.2 GL. Victoria has listed no new significant licensed or permitted dam sites since the construction of the Woodglen No. 2 Dam in 2009. In Tasmania, where the Department of Primary Industries, Parks, Water and Environment has ‘number of new dam works permits’ as a key performance indicator, 40 dams were approved in 2013–14 (Tasmanian Government 2015). This was the lowest annual total number of permits since 2000. The total storage capacity of the new dam works (including new dams and enlargements) approved was 11.3 GL, with an average of 284 ML, down from a 5-year peak of 550 ML per permitted development in 2012–13.

In Queensland, the Nathan Dam and pipeline approval process entered its 8th year in 2016. The dam, with a proposed capacity of 888 GL, was gazetted in 2008, and a supplementary environmental impact assessment (EIS) is under consideration, following an initial EIS developed in 2012. The Nathan Dam is just one dam in a proposed new era of national water infrastructure development announced in mid-2015, as part of an overall strategy to boost the competitiveness of Australia’s agricultural sector and to develop northern Australia. The envisaged water infrastructure developments may build or augment existing water infrastructure, including dams, pipelines or managed aquifer recharge. Augmentation considerations include existing projects in the Murray–Darling Basin, the Great Artesian Basin and Tasmania.

Groundwater

Groundwater is a key component in water supply across much of Australia. In many ways, less is known about groundwater, and groundwater is considered less often than supply from surface-water and climate-resilient sources. (See Box WAT2 for an example from one of the more studied aquifers in the country.)

In recent years, groundwater use across large urban areas has fluctuated, reflecting year-to-year variability in supply and demand factors. Overall, groundwater for urban demand (Table WAT4) is not a large proportion of the total water supply reported in the National Water Account, although investigations of managed aquifer recharge may see this grow in future. In many rural areas, groundwater already provides most of the water supply.

A small—but potentially relevant—groundwater and surface-water issue is that of the water extracted during coal-seam gas production. This has been reported to vary from 5 to 300 ML per well per year (NSW Office of Water 2013; Queensland Government 2016). Also, because of the natural and human-sourced chemicals used (such as fracking fluids), coal-seam gas production needs to be managed carefully to minimise environmental impacts. The Queensland Government (Queensland Government 2016) is also periodically assessing underground water impacts of coal-seam gas production in the Surat Cumulative Management Area.

Table WAT4 Groundwater abstraction for some areas,a 2011–12 to 2014–15

Area or capital city

2011–12

(ML)

2012–13

(ML)

2013–14

(ML)

2014–15

(ML)

Perth

514,995

486,741

479,618

483,191

Melbourne

13,173

15,478

14,414

19,166b

Adelaide

17,379

54,287

43,699

51,461

South-east Queensland (including Brisbane)

3,925

5,300

7,516

6,911

ML = megalitres

a Groundwater store information is not available for the Sydney National Water Account region, because volumes related to groundwater store could not be quantified in a way that is complete, neutral and free from material error. Also, groundwater is generally not recognised in the water accounting statements, because its contribution is very minimal.

b Additional data were available in 2015.

Source: National Water Account

 

Argent RM (2016). Inland water: Water resource development. In: Australia state of the environment 2016, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/theme/inland-water/topic/2016/water-resource-development, DOI 10.4226/94/58b656cfc28d1