From challenges, opportunities flow in the Murray-Darling basin

There have been rapid changes in irrigation in the Murray-Darling basin over the past twenty years. Factors such as declining water availability, developing water markets and the introduction of carryover have all played a part in this transformation.

Water recovery for the environment and modern irrigation systems have also influenced strategies for delivering environmentally conscious water operations. At the same time, there have been significant advances in weather, climate and hydrological forecasting.

In the recent webinar 'Challenges in river operations and water forecasting opportunities', four panelists discussed the challenges in river operations and water forecasting opportunities. Hosted by Professor Sharon Davis for the Water, Environment and Agriculture Platform, our panelists Jacqui Hickey, Mark Bailey, Debra Hudson and QJ Wang shared their insights on the topic.

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Current methods to tackle intrinsic challenges

The Murray River system, being the most significant in Australia, faces a wide range of operational and forecasting challenges. To begin with, the sheer length of the river brings about many variables.

“There are long travel times, [with] key demand locations up to five or six weeks downstream of storage, so we are required to look into the future and try to guess what those demands are going to be and therefore what type of flows we need have in the river,” says Jacqui Hickey, who was previously Acting General Manager, Applied Science, Murray Darling Basin Authority (MDBA), and is currently Assistant Secretary at the Commonwealth Environmental Water Office.

“We've got to navigate changing channel capacities through the system.”

Some challenges are posed by the natural environment itself, such as the Barmah Choke, which is a narrow section of the river that restricts river flow to the lowest in any stretch of the Murray. As a significant amount of the demand in the system sits downstream of the Barmah Choke, it is essential for river operators to ensure water needs are being met during winter and spring. Comprehensive forecasting allows environmentally detrimental unseasonal flooding – or forced flooding during summer months – to be avoided, according to Ms Hickey.

Millennium drought, a turning point for water forecasting

The last 15 years has been a time of tremendous progress in water forecasting, according to QJ Wang, Professor of Hydrological Forecasting at the University of Melbourne. The event that was the impetus for change was the Millennium drought, which required the Bureau of Meteorology, CSIRO, Australian universities and water agencies to work together to tackle local issues. This led to the development of world-class operational forecasting services, including seasonal stream flow forecasting, seven-day stream flow forecasting and the expansion of a gridded hydrological forecasting system.

The Millennium drought was also a turning point in terms of rainfall rejection, says Dr Mark Bailey, Manager of Water Resources at Goulburn Murray Water (GMW).

“One of the things that we have seen particularly since the Millennium drought is a change in the sophistication of irrigators and the way in which they plan their water.”

For farmers, taking advantage of information used by river operators allows them to be increasingly strategic in planning their water use.

“If they're seeing an indication of potential rainfall coming through, particularly in times where we've had water shortages, they're likely to shut off early. [And] the more notice we get from them, the more we can pass the information through to the MDBA or our own operators to cut back on water delivery, and minimise the potential for that unseasonal flooding.”

As a result, there has been a reduction in the rate of rainfall rejections compared to before the Millennium drought, which were considered so detrimental to the forest.

Looking to the future

All panelists agreed that climate change will bring exceptional levels of unpredictability in the management of the Murray-Darling basin – but the future of the industry is also set to be a time of great progress.

The rise of artificial intelligence presents a new realm of possibility for water demand forecasting, with a lot of the potential still largely untapped, according to Prof Wang.

“We have been able to use more structured statistical type modelling, looking at the different industries how they respond to the water availability, commodity price and rainfall forecasts, as well as the different characteristics of different regions. Through that we can model a range of industries and regions in terms of the water use and how they respond to the different variables," says Prof Wang.

Looking forward into the next ten years, the level of expectations for scientists and others in the industry will only increase, says Dr Bailey.

“The Bureau [of Meteorology], the University of Melbourne, other academic agencies such as MDBA and GMW – we've been charged with making changes, both in terms of the environment, but also how things such as the basin plan are implemented, and what customers are expecting. They're the ones who are paying for the operation, so there's a lot of work going on to make sure that we're standing at the forefront of the water operations, whether it's running a channel [or] whether it's running a river the size of the Murray.”

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First published on 24 April 2023.

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