Drought
Rainfall deficiencies and water availability

Rainfall deficiencies persist in south-east Queensland

March rainfall was below average for parts of the far northern tropics, extending into parts of Western Australia's northern interior and the south-west of the Northern Territory, and in north-western New South Wales and some adjacent parts of Queensland and South Australia.

Rainfall for March was above average for an area extending from the central Northern Territory, through the Gulf Country and central Queensland, along parts of eastern Australia, and for much of the west of Western Australia and northern Tasmania.

For the 4-month period starting December 2022, serious deficiencies (totals in the lowest 10% since 1900) are in place in small parts of coastal south-west Western Australia, south-east Queensland, and pockets of north-eastern New South Wales. Compared to February, deficiencies have eased in north-eastern New South Wales, north-west Victoria, and western Tasmania.

For the 16-month period starting December 2021, deficiencies persist in western Tasmania and far south-west Western Australia. March rainfall has reduced the extent of serious rainfall deficiencies in western Tasmania.

The long-range forecast released on 30 March 2023 indicates that for April to June, below median rainfall is likely (60 to 80% chance) for most of Australia away from the east coast, Far North Queensland, and southern Tasmania. Maximum temperatures are likely to be above average across much of the country and minimum temperatures likely to be above average around most of the coast of Australia and much of the west, but below average in parts of the interior.

State of the Climate 2022 reported that there has been a shift towards drier conditions across the south-west and south-east Australia, especially for the cool season months of April to October. Since the 1990s, in the absence of strong 'wet' drivers, autumn rainfall in southern Australia has generally been drier than average.

Deficiencies for the 4 months since December 2022

March rainfall was below average for parts of the far northern tropics, extending into parts of Western Australia's northern interior and the south-east of the Northern Territory, and in north-western New South Wales and some adjacent parts of Queensland and South Australia.

For the 4-month period starting December 2022, serious deficiencies (totals in the lowest 10% since 1900) are in place in small parts of coastal south-west Western Australia, south-east Queensland, and pockets of north-eastern New South Wales. Compared to February, deficiencies have eased in north-eastern New South Wales and adjacent areas across the Queensland border, north-west Victoria, western Tasmania, and south-west Western Australia.

In Queensland, a band of severe rainfall deficiencies (totals in the lowest 5% of historical observations) extends from the Wide Bay and Burnett coast inland to the region around Roma. March rainfall has lifted rainfall totals out of the lowest 10% of historical observations in much of the Maranoa and Warrego, and the Darling Downs and Granite Belt districts.

An area of severe deficiency persists in the far south-west of Western Australia, and on the south-west coast of Tasmania.

Deficiencies for the 16 months since December 2021

For the 16-month period starting December 2021, serious rainfall deficiencies continue in small parts of coastal south-west Western Australia and western Tasmania. While the overall extent of the area affected by rainfall deficiencies remains fairly similar, the severity of deficiencies has decreased in western Tasmania compared to deficiencies for the 15-month period to February 2023.

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Soil moisture

Root-zone soil moisture (soil moisture in the top 100 cm) was below average across areas of Australia along the east coast, south coast of Western Australia, south-west Tasmania, and in a large area spanning north-west New South Wales, southern and south-west Queensland, eastern and northern parts of pastoral South Australia, and the south of the Northern Territory.

March rainfall increased soil moisture along areas of the western coast of South West Western Australia and in western Tasmania; soil moisture for March was close to average in much of these areas, and had been very much below average during February. Elsewhere, compared to last month soil moisture has also decreased in eastern Victoria and south-eastern New South Wales, much of inland Australia, and eastern Queensland. Heavy rainfall and flooding during the month has seen soil moisture increase in areas to the south of the Gulf of Carpentaria, and is above average for much of the north-western quadrant of Queensland and the northern half of the Northern Territory except the Top End.

Evaporative stress

Evaporative stress for the 4 weeks ending 29 March 2023 remains elevated for much of mainland Australia away from the tropics, the east coast, and coastal south-eastern South Australia and coastal western Victoria.

Compared to last month, ESI has decreased in intensity in south-eastern Queensland, north-western Western Australia, Tasmania, and Queensland's Channel Country. ESI has increased in intensity (index is negative) across much of Australia, particularly in inland areas of the south-eastern mainland and in central Australia.

See the journal publication for further details on calculation and use of evaporative stress index in drought monitoring.

• March rainfall was below average for parts of the far northern tropics, extending into parts of Western Australia's northern interior and the south-west of the Northern Territory, in north-western New South Wales, and some adjacent parts of Queensland and South Australia.
• For the period commencing December 2022 areas of serious or severe rainfall deficiencies (totals in the lowest 10% of observations since 1900) are in place in south-east Queensland and pockets of north-eastern New South Wales, and in far south-west Western Australia.
• Soil moisture remains below average along the coast from south-east Queensland to south-eastern Victoria, in much of south coast Western Australia and western Tasmania, but has increased along the northern coast of New South Wales.
• Streamflows were low in south-west Western Australia, the north of the Murray—Darling Basin, and far north-east and south-east Queensland.
• Storage levels were low in some parts of central Queensland, central and western Tasmania, south-east New South Wales, western Victoria, South Australia, and many urban storages for Perth in Western Australia.
• For April to June, below median rainfall is likely for most of Australia away from the east coast and southern Tasmania, and maximum temperatures are likely to be above average.

Streamflows high in parts of the north and south-east Australia west of the ranges; low in parts of east coast Australia and south-west Western Australia

In March, streamflows were average at 47% of sites (based on records since 1975), spread across the country. Lower than average streamflows were observed at 16% of the 868 sites, mostly associated with below average rainfall and drier catchment conditions in the north of the Murray—Darling Basin and far north-east and south-east Queensland. Due to lower-than-average rainfall in the previous month, streamflows in the south-west of Western Australia were mainly below average to very much below average.

In March, above to very much above average streamflows were observed at 37% of sites, mainly in south-central and eastern areas of the Murray—Darling Basin, Victoria, wet tropics of Queensland, the Northern Territory, and scattered sites in the Western Australia. Very much above average rainfall and flooding in the Northern Territory and north-west Queensland resulted in higher than average streamflows in rivers in these areas, and major or moderate flood warnings were issued for some catchments across the Northern Territory and western Queensland.

Overall high storage levels across the country with a few pockets of low storage levels

In March, areas in north-east Northern Territory, north-west Queensland, western to central Western Australia and some parts of eastern Australia received above average to very much above average rainfall. Soil moisture was very much above average in areas of the north-east Northern Territory and north-west Queensland. This contributed to generation of runoff and subsequent flooding in these areas. March saw a slight increase in some storage levels from February, particularly in south-east Queensland, the Northern Territory, and some storages in the eastern Australia. Despite most of Australia's major storages being at high levels, there remain several locations with low storage volumes: particularly in central Queensland, central and western Tasmania, south-east New South Wales, western Victoria, South Australia, and many urban storages for Perth.

In March north-west New South Wales received below average rainfall and dry catchment conditions resulted in a slight decrease in some storage levels in the Murray—Darling Basin. At the end of March, the combined storages in the Murray—Darling Basin were 87.0% full, 0.5% down from the same time last year.

With drier catchment conditions across southern Western Australia in previous month, Perth's surface water storages were 43.3% at the end of March (down from 48.6% at the same time last year). However, with the long-term decline of surface water inflows into storages, the city's water supply is generally more reliant on desalination and groundwater sources than surface water.

Despite average to above average rainfall and average soil moisture conditions across Tasmania, storages volume in Tasmania remains around half of full capacity (51.7%) which is slightly lower (0.2%) than last month and also lower than at the same time last year.

Water levels in the Nogoa Mackenzie system in central Queensland remain low, slightly decreasing to 44.4% by the end of March (up from 20.4% at the same time last year). In central Queensland, water storage in Fairbairn was below half capacity at the end of March at 43.7% (up from 19.3% at the same time last year).

Further detail on individual Murray–Darling Basin catchments can be found in the Murray–Darling Basin Water Information Portal.

An overview of streamflow, stream salinity, and storage levels for Drainage Divisions across Australia can be found in the Monthly Water Update.