Water in Australia
Water in Australia provides a country wide picture of water availability and use in a particular financial year. Water in Australia 2014-15 covers the period 1 July 2014 to 30 June 2015 and assesses the year in terms of:
- Dry conditions with declining reserves
- Continuing trade and declining water use
- Varying responses to water availability
- Reduced storage at the start of 2015–16
Monthly Water Update provides a regular snapshot of rainfall and streamflow for the previous month.
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Dry conditions with declining reserves
With near-El Niño conditions in place in the Pacific Ocean in spring 2014, daily maximum temperatures reached new record highs in many parts of the country. During March 2015, there was a notable heatwave across northern and central Australia, and these high temperatures increased the potential for higher-than-normal evaporation and rapid depletion of soil moisture.
The usual spatial and temporal variability in rainfall and streamflow existed throughout 2014–15. In the east and south, dry conditions prevailed across vast areas, and, overall, the annual average rainfall was 10 per cent below the long-term national average. However, despite the national average, some areas had ample rainfall—large areas in the central north and along the New South Wales coast received 100–400 mm above the annual average rainfall.
The low rainfall and high temperatures had a substantial impact on streamflow. At the Bureau of Meteorology's Hydrologic Reference Stations that are not affected by developments, most had average or below-average streamflow.
Overall, the accessible surface water storage volume for agriculture and urban use at the beginning of the assessment period was 73 per cent of the total storage capacity. By the end of the assessment period, the accessible storage volume had declined to 64 per cent.
Upper aquifers had more bores with declining trends in water levels than in the 2013–14 assessment, although this varied spatially. Along the east coast, fewer bores showed rising trends, especially in alluvial aquifers in the Murray–Darling Basin. Patterns in the Perth Basin and the Northern Territory were largely unchanged.
Similarly, the middle aquifers in eastern Australia had more bores with declining trends in water levels than in the 2013–14 analysis. However, the Perth Basin to the west showed increased levels, indicating a decrease in extractions from the middle aquifer. Trends in the lower aquifer were largely unchanged since the 2013–14 assessment.
Continuing trade and declining water use
Australia's water market continued to facilitate high levels of buying and selling water entitlements and allocations. This allowed water to move between various urban, agricultural and environmental uses. Entitlement trade volumes dropped nationally during 2014–15, but remained higher than the wet years from 2010–11 to 2012–13. Allocation trading volumes in the southern Murray–Darling Basin were maintained at similar high levels to 2013–14.
The estimated total bulk extractions for non-environmental use from rivers, dams, high-yielding aquifers, and recycling and desalination plants across Australia were 16 700 GL in 2014–15. This volume is 4 per cent lower than in 2013–14.
The total extraction of water for agricultural use in Australia in 2014–15 was estimated at 12 600 GL—about 6 per cent less than the previous year. Australian water users continued to use surface water as their primary source of water because of its high accessibility and therefore lower extraction cost. However, groundwater extractions did increase in some areas to supplement supplies.
Varying responses to water availability
Regulated water supply systems across Australia use the largest volumes of water. In the north and along the Queensland coast, there is relatively high physical water availability throughout the year, and allocations and use vary little between years, with generally full allocations announced against the entitlements.
The northern Murray–Darling Basin catchments all showed increasing physical water availability coming out of the 1996–2010 Millennium Drought, with allocations and use following the same trend, often with a one-year time lag. In 2014–15, physical availability and, consequently, annual water-use permissions were the lowest for the past five years, resulting in use approaching total water-use permissions.
The southern Murray–Darling Basin catchments have a lower level of variability in their physical water availability volumes, because of the larger storage capacity in the southern regulated systems and less variable rainfall conditions between years. As a result, the variability in the combined volume of allocation and carryover is lower between years, and use levels during the past three years have remained fairly stable.
Use in major urban centres is mostly provided from surface water storages. In 2014–15, storage volumes and inflows were high enough to meet the demands. The exceptions were Perth and Adelaide, where storage capacities and volumes remained low. Surface water use in these cities was supplemented by other sources, particularly groundwater, desalinated water and transfers from outside of the storage catchments.
Reduced storage at the start of 2015–16
In the Murray–Darling Basin, storage volumes had dropped substantially in most catchments by July 2015. Opening allocations in 2015–16 were mostly zero for the general- and medium-security entitlements. Even some high-security entitlements were given less than 100 per cent opening allocations for 2015–16. Additionally, carryover volumes were also substantially lower at the start of 2015–16 than in 2014–15.
Outside the Murray–Darling Basin, the change in storage volume between the start of 2014–15 and 2015–16 was much more variable.