Australia & New Zealand: Water deficits forecast in New Zealand

25 May 2021

THE BIG PICTURE
The 12-month forecast through January 2022 indicates surpluses, primarily moderate, in southeastern Australia from the eastern Murray-Darling Basin to the coast. Near the mouth of the Murray River, however, surpluses will be intense.

In Queensland, a small pocket of intense deficit is expected on the coast north of Townsville, but a few pockets of moderate surplus are forecast in the Cape York Peninsula of the Far North.

Australia_New_Zealand_Composite_Adjusted_202102-202201_12mo_twitter.png

Surpluses are also forecast in Top End, Northern Territory in the region of the Daly and Katherine Rivers.

In Western Australia, deficits are expected on the coast in the Kimberley region and from the Great Sandy Desert to the coast near Broome. Transitional conditions are forecast southwest of the Gibson Desert and pockets of surplus in the Great Victoria Desert. In the state’s southwestern corner, surpluses are forecast in the Avon River Basin east of Perth. Some surpluses are expected in the center of the Australia in the Simpson Desert and in western South Australia. Tasmania can expect deficits near Hobart and in the southwest.

Deficits are also forecast for many regions of New Zealand including moderate to severe anomalies near Lake Taupo and the Waikato River area on North Island, and along South Island’s east coast and through the southeast. Anomalies will be exceptional near the three glacial lakes - Pukaki, Tekapo, and Ōhau - in the Waitaki River Watershed of South Island.

FORECAST BREAKDOWN
The 3-month maps (below) show the evolving conditions in greater detail.

The forecast through July indicates that surpluses in southeastern Australia will shrink, retreating from the Upper Murray River region but persisting in northeastern New South Wales. Intense surpluses will persist near the mouth of the Murray in South Australia. In Tasmania, exceptional deficits will emerge surrounding Lakes Pedder and Gordon and moderate deficits in the Derwent Estuary near Hobart. Back in mainland Australia, surpluses will increase in the Atherton Tableland in northern Queensland and persist in a pocket in eastern Cape York. Surpluses will also persist near Katherine in Top End, Northern Territory, will re-emerge in West Australia between the Great Victoria Desert and the Gibson Desert, and will shrink in the Avon River Watershed east of Perth.

Australia_New_Zealand_Composite_Adjusted_202102-202201_3mo_twitter.png

Deficits are forecast in New Zealand, becoming exceptional on North Island in the Waikato River Watershed. On South Island, deficits are forecast along the island’s eastern shore and well inland in the south, with exceptional anomalies in the glacial lakes. Anomalies in New Caledonia will downgrade, becoming mild.

From August through October, surpluses will persist in southeastern Australia from the Macquarie River to the Macintyre, and near the mouth of the Murray. Surpluses in Far North Queensland and Top End, Northern Territory will begin to transition, and exceptional deficits will emerge in Arnhem Land, Top End. In Western Australia, surpluses will retreat from the Avon River region but persist southwest of the Gibson Desert. Exceptional deficits will emerge in western Tasmania, but deficits in New Zealand will shrink considerably.

The forecast for the final months – November 2021 through January 2022 – indicates that deficits will retreat in the region and surpluses, primarily moderate, will increase in southeastern Australia as anomalies emerge from Canberra through eastern Victoria.

Please note that WSIM forecast skill declines with longer lead times.

IMPACTS
Facing a second year of drought in many regions, New Zealand will make an additional $900,000 (US $697,000) available to farmers for drought relief including resources to connect farmers with available feed sources.

In just a single year the sheep population in the Hawke’s Bay region of New Zealand’s North Island has dropped by 12 percent, around 346,000. Ongoing drought, among other factors, contributed to the decline by reducing pasture acreage and forcing herd culling.

Farmers in South Island’s Banks Peninsula are calling the drought the worst in a quarter of a century, with January through March rainfall a mere 33 percent of average.

Industry losses from the devastating floods that hit New South Wales and Queensland, Australia in March after extreme rainfall are estimated at $1.055 billion (~US $825 million), as calculated by a catastrophic insurance organization. Some areas of NSW’s coastal region recorded the highest precipitation since 1900, between 600 to 800mm (~27-31 inches).

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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