Drought
Rainfall deficiencies and water availability

Deficiencies continue in western Tasmania following very much below average January rainfall

January rainfall was below average for south-east Queensland and north-eastern New South Wales, the southern half of Victoria, much of Tasmania, and parts of south-west Western Australia.

However, rainfall was above or very much above average for most of Queensland away from the southern districts, most of pastoral South Australia, the southern half of the Northern Territory, most of the north and north-west of Western Australia, and some parts of western and southern New South Wales.

For the 14-month period starting December 2021, serious rainfall deficiencies (totals in the lowest 10% since 1900) remain in western Tasmania, and part of south-west Western Australia. Compared to the 13-month period ending December 2022 there was little change in deficiencies over the past month.

Multi-year rainfall deficiencies, which originated during the 2017–2019 drought, have been almost entirely removed from the eastern states. The largest area of remaining multi-year rainfall deficiencies is in the Goldfields District of Western Australia, with smaller pockets in south-west Western Australia and the north of the Northern Territory.

The long-range forecast released on 02 February 2023 indicates that for February to April rainfall much of the country has close to equal chances of above or below median rainfall, but with a chance (60 to 70%) of below median rainfall on the west coast and some parts of inland Australia. Above median rainfall is moderately likely (60 to 70% chance) for Tasmania, the eastern Top End, and northern Cape York Peninsula.

Deficiencies for the 14 months since December 2021

Rainfall for January was below average for south-east Queensland and north-eastern New South Wales, the southern half of Victoria, much of Tasmania, and parts of south-west Western Australia; but above or very much above average for most of Queensland away from the southern districts, most of pastoral South Australia, the southern half of the Northern Territory, most of the north and north-west of Western Australia, and some parts of western and southern New South Wales.

For the 14-month period ending January 2023, serious rainfall deficiencies (in the lowest 10% since 1900) remain in western Tasmania and a small area of south-west Western Australia. Compared with the 13-month period ending December 2022, rainfall deficiencies have changed little.

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Soil moisture

Root-zone soil moisture (soil moisture in the top 100 cm) was below average in parts of south-west and southern Western Australia, western Tasmania, and north-eastern New South Wales to south-eastern Queensland.

Soil moisture was above average for the Kimberley and part of north-western Western Australia, the Northern Territory, most of Queensland except southern regions, and an area of south-west to central New South Wales.

In recent months, very wet soils across south-eastern Australia have been a significant contributor to the severity of flooding and have also contributed to increased inflows into inland water storages.

Evaporative stress

Evaporative stress for the 4 weeks ending 31 January 2023 increased over much of the Northern Territory and most of Queensland away from southern districts, but has decreased across much of southern Australia. Evaporative stress remains elevated for much of western and southern Western Australia, much of southern Queensland, and west coast Tasmania.

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

• January rainfall was below average for south-east Queensland and north-eastern New South Wales, the southern half of Victoria, much of Tasmania, and parts of south-west Western Australia.
• Serious rainfall deficiencies (totals in the lowest 10% of observations since 1900) for the period starting December 2021 remain in western Tasmania and a small area of south-west Western Australia.
• Soil moisture was above average for most of northern Australia, but below average in parts of south-west and southern Western Australia, western Tasmania, and north-eastern New South Wales to south-eastern Queensland.
• Low streamflows were observed mostly in south-west Western Australia, inland and south-eastern Queensland, and north-eastern New South Wales.
• High streamflows were observed at sites in wet tropics of Queensland, inland New South Wales, and north-west Western Australia.
• At the end of January, Australia's total storage volume was 79.1% of full capacity, with urban storages in all capital cities sitting above 80%, except for Perth (52.6%).
• The combined storages in the Murray–Darling Basin were 96.7% full. This is up from 90.8% at the end of January 2022.
• Low storage levels continue in some parts of central Queensland, central Tasmania, south-east New South Wales, and some urban storages for Perth and Western Australia.

Streamflows high in the north-east and low in south-west Western Australia

In January, above to very much above average streamflows (based on records since 1975) were observed at 47% of sites, mainly in the Southern Murray–Darling Basin, south-east coast (Victoria), the Kimberly in Western Australia, and the wet tropics of Queensland. Despite average to below average rainfall, streamflows were high in the Southern Murray–Darling Basin because of the downstream movement of floodwater that started in November 2022. Numerous flood warnings were issued for catchments across western New South Wales and South Australia. High streamflows in the Northern Territory, Kimberly, and coastal areas of tropical Queensland were associated with high rainfall and resultant flooding along the path of ex-Tropical Cyclone Ellie.

In January, streamflows were average at 41% of sites, mainly in south-eastern Australia, the Top End of the Northern Territory, and Western Australia. Lower than average streamflows were observed at 12% of the 873 sites, mostly associated with below average rainfall and drier catchment conditions in south-west Western Australia, western Tasmania, inland and south-eastern Queensland, north-eastern New South Wales, and at some scattered sites in south-eastern Australia.

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

Above average rainfall in areas of north-west Western Australia, north-east Queensland, and central South Australia resulted in a slight increase in some storage levels, particularly in north-east Queensland and Western Australia.

By the end of January, the total water storage volume in Australia (across Australia's 306 public storages) was 79.1% of full capacity; slightly higher than the previous month and higher than at the same time last year. The combined storages in the Murray–Darling Basin were 96.7% full, up from 90.8% at the same time last year. Despite most of the major storages being at high levels, there remain several pockets of low storage volumes: particularly in central Queensland, central Tasmania, south-east New South Wales, some urban storages for Perth, and one storage in the north-west Northern Territory.

Perth's surface water storages were just above half capacity at the end of January at 52.6% (slightly down from 53.2% 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.

In the Pilbara in Western Australia, Harding Dam was just above half capacity at the end of January at 57.5% (up from 44.4% at the same time last year).

With drier catchment conditions across western Tasmania in previous months, storage volumes in Tasmania remained around half of full capacity at the end of January (53.3%); lower (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 despite increasing to 45.0% by the end of January (up from 25% at the same time last year). In central Queensland, Fairbairn was below half capacity at the end of January at 44.1% (up from 24% 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.