Is this the worst drought of them all?

A recent article in the Narrabri Courier raised the issue of whether or not this drought is the daddy of them all, on par with that description, or uncomfortably close to it.

The article quoted Will Turnbull, who is on the Darling between Bourke and Brewarrina, saying there is still a long way to go before this drought mirrors the Federation drought.

He noted that the Darling was dry at Bourke for more than twelve months: between April 1902 and May 1903.

“Since August last year, we’ve seen seven months of no flow at Bourke. We have another six months to beat the 1902/03 record.”

As noted elsewhere, the Darling River at Menindee ceased to flow 48 times between 1885 and 1960, and the river did not flow for 364 days in the 1902–3 drought.

As noted by the Bureau of Meteorology, by 1902 Australia's sheep population dropped from its 1891 level of 106 million to fewer than 54 million. Cattle numbers fell by more than 40 per cent. Sheep numbers did not return to 100 million until 1925. ( No cotton grown then and negligible wheat in the North West).

This prompted us to dig into the historical records to examine the frequency of droughts and try to compare their severity and impact on farming and grazing communities.

Will Turnbull gave us a guide, noting in the Courier that South Eastern Australia experienced 27 drought years between 1788 and 1860.

BOM records show that in 1826−29 severe drought in NSW caused Lake George to dry up and the Darling River to cease flowing.

There were at least 10 major droughts between 1860 and 2000, plus one most of us will remember well—the Millennium Drought from 2001 to 2009.

We then had a breather before this one arrived in 2018, when Australia’s annual rainfall was 11% below average, the lowest recorded since 2005 in the middle of the Millennium drought, which was accompanied by extreme and record temperatures as well.

History tells us that we are not always saddled with drought. The largest flood recorded along the Darling River was in 1890. The first half of the 20th century was very dry with few small floods – in 1917, 1921, 1931 and 1941.  The second half of the 20th century was much wetter, with big floods in the 1950s, 1970s, 1983 and 1990.

The largest flood in the 20th century was in 1956 when both the Darling and Murray rivers were in flood. This caused towns from Brewarrina to Wentworth to be isolated for months. Wentworth itself was nearly inundated, notes the Discovering the Darling website.

In two out of three years, there were small floods in the upper reaches of the Darling that flowed into the Menindee Lakes, northern anabranch lakes and Darling River billabongs. One in 10 years, there were moderate floods that spilled onto the floodplain and filled the southern-most lakes and wetlands for months to years.

The primary indicator of drought and water availability in Australia is rainfall. Australia is the second-driest continent in the world, with mean annual rainfall less than 600mm for more than 80 per cent of Australia. Australia (whole continent) receives an average of 419 mm/year – making us the driest inhabited continent on Earth.

Bureau of Meteorology records since the 1860s show that a ‘severe’ drought has occurred in Australia, on average, once every 18 years. This does not indicate that severe drought regularly and predictably recurs every 18 years; intervals between severe droughts have varied from four to 38 years.

Up to the mid-eighties, the major drought periods of 1895-1903 and 1958-68 and the major drought of 1982-83 were the most severe in terms of rainfall deficiency and their effects on primary production. In south-eastern Australia the droughts of 1967-68 and 1982-83 were notably extreme.

There have been six other droughts of a lesser degree of intensity, but nevertheless causing appreciable losses in large areas of several States. In south-eastern Australia there have been eight severe droughts, mostly encompassed within the major Australian droughts.

Australia has experienced several major droughts during the 20th and early 21st centuries. The most severe droughts were the Federation Drought (1895–1903), the World War II drought (1939–1945) and the Millennium Drought (1996–2010).

The Millennium drought is said by some to be the worst drought recorded since European settlement. This drought affected most of southern Australia, including its largest cities and largest agricultural region (the Murray–Darling Basin).

It commenced with low rainfall conditions in late 1996 and through 1997, and worsened through particularly dry years in 2001 and 2002. By 2003 it was recognised as the worst drought on record.

The year 2006 was the driest on record for many parts of the country and conditions remained hot and dry through to early 2010.

South-east Australia experienced its second driest year on record in 2006, particularly affecting the major agricultural region of the Murray-Darling Basin. At this point, the Bureau of Meteorology estimated that south-eastern Australia had missed the equivalent of a full year's rain in the previous 11 years.

The emergence of La Niña weather conditions in 2010 rapidly ended the drought, and led to floods in some locations.

During most summers, the Darling River typically becomes a series of deep waterholes. Similarly, the lakes at Menindee and on the Great Darling Anabranch dry up for many years between floods. From 1890 to 1961, water flowed the complete length of the Great Darling Anabranch to the Murray River only nine times.

From our brief search of historical data, it appears that the Millennium drought may have topped this one (so far), but only marginally, although it was the Grand Champion for length.

The BOM noted that In the order of 20 cotton communities and 10,000 people directly employed by the cotton industry were impacted by that drought.

The main areas affected were in New South Wales: Menindee, where the area under production was reduced by 100%, Bourke, area reduced by 99%, Walgett by 95%, the Macquarie River by 74% and Gwydir River by 60%.

In Queensland, the worst-affected areas were Biloela, which reduced the area under production by 100%, Dirranbandi, by 91%, Central Highlands by 82% and Darling Downs by 78%. Bourke only had adequate water for one cotton crop in the previous five years.

There is little chance that all Australia could be in drought at the same time. Some droughts are long-lived; some are short and intense, causing significant damage. Some can be localised while other parts of the country enjoy bountiful rain. Some regional droughts are not related to El Niño events, and are therefore harder to forecast.

Our journey back through history leaves us with a few salient take home messages.

Firstly, droughts are inevitable in Australia. They are part of the landscape. Part of our DNA.

Secondly, you can’t predict when or where they will occur, how long they will last, or what damage they will do.

Thirdly, the cycles of floods and droughts are influenced by semi-arid climate and sporadic rainfall across most of our river catchments, making both floods and droughts highly variable.

Finally, while droughts may be devastating on people, the environment, rivers, creeks, streams and storages, and have dire social, economic, ecological and economic consequences, they always end faster than they start.

Let’s drink to that.