Droughts in the Upper Hunter Area
Featured Image: Acknowledge ‘Hunter Drought’
Acknowledgment: “Growing the Hunter 1994”, Pages 29 & 30
With the subject of drought on everyone’s minds, Ross Watson, District Agronomist NSW Agriculture, Scone, took a look at some surprising drought statistics for the Upper Hunter.
Comment: Although this is a ‘dated’ report the principles still apply. I’m tempted to trot out the hoary old cliché ‘elementary my dear Watson’; but I won’t! However if we fail to learn the lessons of history we are condemned to repeat the same mistakes.
Based on records from the Upper Hunter Rural Lands Protection Board from as far back as 1952 (to 1991), the Upper Hunter has spent a total of nine years out of the 40 under drought declaration. In other words 23% of the time the district is drought affected. This may seem alarmingly high but most districts in NSW range between 15 to 30% drought affected over the same period. That’s the bad news; but the good news is that 77% of the time we have good or reasonable conditions.
Ross is a consummate professional. I saw him recently at the Scone PO. He told me I should get myself rapidly ‘up-to-date’ by consulting his excellent website. He makes some startling observations.
As posted on several previous occasions now, this drought (2017+2018) was amongst my “Gang of 5” worst drought periods in the last 100 years, breaking several records during the last 24-30 months. But this drought, as at June 2019, has decided to continue in this mode and become our driest recorded 2 year June to June period, in some 118 years of records. (See Graph on website).
Droughts have been and will continue to be a feature of our environment. Even if the sceptics are correct we are looking down the barrel of a hotter planet and increasingly more erratic and extreme weather patterns. Therefore management strategies and property development needs to take into account this significant factor. When we look at historical records of droughts in the upper Hunter, we may be able to learn some points to help us with our management in the future.
From the records it can be seen that:
- Scone experienced 111 months (9.25 years) of drought declaration out of 472 months (39 years)
- Merriwa experienced 105 months (8.75 years) of drought declaration out of 472 months (39 years)
- 22 out of the last 40 (to 1994) years experienced some period of drought; that is 55% of the time
- 18 out of the last 40 (to 1994) did not experience any period of drought; that is 45% of the time
- The longest single period of drought declaration is 21 months from February 1965 to October 1966; and February 1980 to November 1981. Ironically both these droughts started and ended at similar times. These long droughts occur one in every 20 years.
The frequency of drought conditions has doubled in the past 20 years (1975 – 1994).
In the first 20 years (1952 – 1971) we experienced only a total of 10 drought months, while in the last 20 years (1972 – 1991) we have experienced a total of almost 70 drought months.
Is this due to seasons or are we inducing drought conditions through the need to run more stock to remain viable? I think it’s probably a combination of both.
Because of the decline in farm incomes in real terms and the need to run our country near its upper stocking limit most of the time, we will probably go into droughts quicker, more regularly feel the effects of them harder and probably come out of them slower. Unfortunately there is no easy answer to this dilemma.
The probability of drought/month figures show:
- Drought conditions are most likely experienced in August and least likely in December
- There is no definite pattern to the occurrence of drought
- Drought conditions can occur in any month of the year
- August is the month of the greatest probability of drought; a one-in-three chance
- Percentage probabilities of drought by time period show that droughts of two months’ duration accounted for 25% of recorded droughts periods; and
- Periods of drought varied between 1 and 21 months
- Most droughts are two months in duration.
- There is a 50% chance that droughts will be less than four months
- There is a 75% chance that droughts will be less than six months
- Almost a 90% chance droughts will be less than nine months
- No droughts have gone longer than 21 months
What might all this mean?
- Drought is a regular feature of our climate. It almost occurs at a frequency equivalent to the hours we sleep per day: about one third of the time
- Management strategies need to be well developed to handle droughts
- Stocking rates need to be conservative or adjusted to reduce the speed and frequency of our regular short term droughts as well as enable quicker recovery after the drought
- More conservation of fodder needs to occur. Supplementary feeds e. g. molasses, hay, grain and silage need to be used to meet feed deficits
- The critical feed period will tend to be May to October due to low pasture growth rates in the winter months even in ‘normal’ seasonal conditions and also the apparent greater frequency of drought conditions in the same period
- Stock water should be a high priority for development wherever possible
- A proportion of native and improved pastures need to be found on all properties
Elementary my dear Watson?
In more recent times Todd Andrews (RLPB Beef Cattle Officer) stated that taking into account all factors (variable rainfall, pasture management, overall ‘quality of country’, pastures & soils, economic vicissitudes, market fluctuations, public demand, wholesaler controls etc.) the Upper Hunter could realistically expect about 2 really good years in every 10 (20%)?
Neither Ross nor Todd talk here about water conservation? How many more Glenbawn Dam iterations do we need apart from ‘on-farm’ storage?
My spouse Sarah and I were ‘farmers’ during the 1980 – 1981 long drought albeit a small acreage (210 acres) of dry land pasture. We somehow managed supported by other income. Would we have done things differently now? Probably; with total de-stocking the most viable option.