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Declining rainfall in parts of Australia, but still plenty of water available: BOM report

Despite a decade of drought and declining rainfall in parts of Australia, there’s still plenty of water to go around. Maroondah reservoir from www.shutterstock.com

Declining rainfall in parts of Australia, but still plenty of water available: BOM report

Despite a decade of drought and declining rainfall in parts of Australia, there’s still plenty of water to go around. Maroondah reservoir from www.shutterstock.com

The Millennium Drought ended more than five years ago, but several years of below-average rainfall and El Niño have brought drought back to many parts of Australia. Our latest report on water in Australia shows rainfall is continuing to decline in eastern Australia and increase in the north.

However in urban areas, where water use has not changed significantly since the Millennium Drought, more water is available for use thanks to technologies such as desalination and recycling.

In a recent article on The Conversation, the Bureau of Meteorology put the case that Australia can now better manage water resources using new water information capability.

Last week the Bureau released a new assessment report on our national water availability and use. Water in Australia 2013–14 examines climatic conditions and the physical hydrology to create the most recent national assessment of Australia’s water resources.

The main findings are outlined below.

Water resources

Since 1950, rainfall has increased in Australia’s north and northwest, but declined along the west coast and most of eastern Australia. This pattern was reflected in 2013–14.

Rainfall affects streamflow and groundwater replenishment, which in turn affects our available water resources.

In southern Queensland and northern New South Wales, a severe drought, which started in 2012, continued in 2013–14. As expected, streamflow in these areas was very much below average in drought-impacted areas.

Annual rainfall, runoff and streamflow conditions, 2013–14. Australian Bureau of Meteorology

The volume of groundwater stored in aquifers is very large compared with surface water and responds more slowly to external influences. As a result, most bores across the country had average groundwater levels in 2013–14.

In South Australia and Queensland, more than one-third of all bores had an above-average level. Below-average groundwater levels were present in 5–20% of bores in each State and Territory.

Water availability

Australia has extensive water supplies and their use is managed by various institutional arrangements. Water availability is being increased by using recycled and desalinated water. At the same time, greater protection is being afforded to the environment through the purchase of entitlements from water users and investments in water-saving infrastructure.

Status of Australia’s major water storages at 30 June 2014. Australian Bureau of Meteorology

Since the Millennium Drought, Australia’s water market has thrived, facilitating the buying and selling of water rights to allow water to be moved and put to more effective use. Entitlement trade increased in 2013–14 to about 2400 gigalitres (GL), and can partly be attributed to entitlements being transferred to the Commonwealth for the environment and partly to declining water storage levels that prompt buyers into the market to secure more water. Allocation trade in 2013–14 was around 5500 GL.

As well as ensuring sustainable water supply for human needs, water resources are managed to ensure that environmental needs are met. Environmental water holders in the Murray–Darling Basin held 3192 GL of surface water entitlements at the end of 2013–14 (increasing from 3160 GL at the end of 2012–13). Of the total allocated environmental water available in 2013–14, 68% was delivered for environmental purposes and 27% was carried over to 2014–15.

Water use

Total water use across Australia was estimated at 23 500 GL in 2013–14. Irrigation (57% of total use) and urban consumption (17% of total use) were the top two water uses.

Estimated total water use in Australia, 2013–14. Australian Bureau of Meteorology

The main irrigation use in 2013–14, at just over 9500 GL, was in the Murray–Darling Basin. The estimated total surface water use for irrigation in the Murray–Darling Basin decreased from 11 000 GL in 2012–13 to about 8400 GL in 2013–14—a drop of 24%.

Groundwater use for irrigation increased by 18%, to 1100 GL, because of drier conditions and limited surface water allocation announcements — particularly in the northern Basin.

Outside the Basin, 3900 GL were used for irrigation, mainly in the Queensland and Victorian coastal regions, the coastal regions surrounding Perth and Adelaide, northeastern Tasmania, and in the Ord irrigation scheme in northern Australia.

Urban residential use in 2013–14 was 185 kilolitre per property, up 3% from 2012–13. However, use per property has not increased significantly from the levels at the end of the Millennium Drought. Total water use in 2013–14 in the major cities showed no significant changes from the recent past.

Though water availability exceeded use in 2013–14, shortages were experienced across large parts of the continent. With Australia’s highly variable and changing climate there will be ongoing challenges to meet the water needs of our nation.

The Bureau’s wide variety of water products are available at: www.bom.gov.au/water, including the Monthly Water Update, Regional Water Information, National Water Account and Water in Australia.