Paddling blind: why we urgently need a water audit



There’s broad support from communities and farmers for proper water audits.
John/Flickr, CC BY-SA

Quentin Grafton, Crawford School of Public Policy, Australian National University and John Williams, Australian National University

In the wake of a damning royal commission and an ABC Four Corners investigation, the federal government has created an Inspector General for the Murray-Darling Basin, to combat water theft, ensure water recovery and efficiency projects are delivered properly, and essentially make sure everyone is acting as they should.

While this is a laudable aim, the Inspector General – currently former Australian Federal Police Commissioner Mike Keelty – cannot hope to do this job without knowing how much water is being used in the Basin, by whom it is used, and where.




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This might seem like basic information, but the Bureau of Meteorology, the Murray-Darling Basin Authority and state water accounts are not up to the task.

We urgently need a comprehensive audit to track the water in the Murray Darling Basin, so Inspector General Keelty can effectively investigate what he has already described as a “river ripe for corruption”.

Up the creek

Back in 2004 all governments in Australia agreed to track and provide information on water in terms of planning, monitoring, trading, environmental management, and on-farm management.

But water accounts still lack many essential features including double-entry accounting. When applied to water, double-entry accounts means that when one person consumes more water, someone else must consume less.




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The technology to track this already exists: satellites that can quantify surface water are successfully being used used in the United States.

If we had monthly water consumption measurements, we could see how much water is being used, by whom, when and where. This would help decision makers see problems before they emerge, such as the mass fish deaths in the Darling River, and respond in real time.

As a recent report from the Natural Resources Commission shows, without proper accounting, too much water is taken upstream – seriously harming downstream communities.

Wide support for an audit

An independent Basin-wide water audit is supported by communities and some irrigators.

In July NSW farmers voted in support of a federal royal commission into “the failings of the Murray Darling Basin Plan”. In our view, this vote shows many farmers support much greater transparency about how much water is being consumed, and by whom.




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Double-entry water consumption accounts would help identify whether the billions of dollars planned in subsidies to increase irrigation efficiency will actually deliver value for money. But irrigation improvements only generate public benefits when more water is left or returns to flow in streams and rivers. Such flows are essential to healthy rivers and sustainable Basin communities.

Irrigators’ crops benefit from increased efficiency, so subsidies help farmers greatly – but it is very unclear whether they do anything for the public good. In fact, they seem to reduce the amount of water that finds its way back into the rivers. Research also shows infrastructure subsidies to improve irrigation efficiency typically increases water consumption at the Basin level.

Our research, published earlier this year in the Australasian Journal of Water Resources shows federal irrigation infrastructure subsidies may have reduced net stream and river levels. This is even after accounting for the water entitlements irrigators provided to the government in exchange for these subsidies.




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Independent audits

Just like financial accounts, water accounts must be independently audited.

For the average taxpayer, who has to justify every dollar they get from the government, it’s hard to imagine how some corporations can be given millions of dollars in subsidies without actual measurements (before and after) of the claimed water savings.

If Newstart recipients need to report and manage their income and have a job plan, as part of a system of appropriate checks and balances, shouldn’t the Australian government also be checking whether billions spent on subsidies for irrigators actually saves water?




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A water audit would cost less than 1% of the money already spent on water infrastructure subsidies in the Basin. Unlike irrigation infrastructure subsidies, a water audit is value for money.

Importantly, independent water consumption accounts would allow the Inspector General for the Murray-Darling Basin to effectively manage our most critical nature resource, water.The Conversation

Quentin Grafton, Director of the Centre for Water Economics, Environment and Policy, Crawford School of Public Policy, Australian National University and John Williams, Adjunct Professor Environment and Natural Resources, Crawford School of Public Policy, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

NSW’s water plan is ‘not working’ but we can save the Barwon-Darling


Barry Hart, Monash University

The plan to manage water in the Barwon-Darling is not working, according to a draft review released last week.

The New South Wales Natural Resources Commission, which released the draft report, found the Barwon-Darling is an “ecosystem in crisis”. The report provides a robust blueprint for a more sustainable water-sharing plan.

The review confirms criticism the existing plan gives too much water to irrigators and has added to pressures on the entire Murray-Darling ecosystem.




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What the plan covers

The draft review examines the 2012 Water Sharing Plan for the Barwon-Darling, which covers 1,600km of the river from Mungindi to Wilcannia. The river here flows south-west through a relatively narrow floodplain with a tightly meandering channel and a highly variable flow pattern.

The river is unregulated and depends heavily on upstream rivers for its water (for example, Condamine–Balonne, Border rivers, Gwydir and Namoi).

January’s massive fish kills around Menindee are only the most recent example of the pressures on the river’s ecosystems. Alongside the fish deaths, research has shown that other aquatic species in the system, such as river mussels, have suffered losses that will take many decades to recover.




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Communities that live along the river told the commission people can no longer fish, swim or drink the river water. Graziers struggle to provide water for their stock because the river dries up more often.

Indigenous communities are particularly affected because without water their strong connection to the river – the Barka – is being damaged. A Barkandji elder told the commission:

The river is everything. It’s my life, my culture. You take the water away from us, we’ve got nothing.

Bad priorities

While the review found drought, upstream water extraction in NSW and Queensland and climate change have all contributed to these problems, the greatest effect comes from inappropriate water-sharing rules, particularly when water levels are low.

The law underpinning river management in NSW prioritises protecting the environment and basic landholder rights (including native title) over irrigation. However, the commission found the current plan does not achieve this.

In fact, the plan has been highly controversial since it was enacted in 2012. This in large parts arose because major changes were made between the draft plan circulated in 2011 and the actual plan gazetted in 2012. The commission documents 16 such changes in the review and rates six as substantial.

The NSW government did not publicly explain the reason for such significant alteration in 2012, but there has been much speculation powerful vested interests influenced the government to provide more water for irrigation.

The most important effect of these changes was letting irrigators take water even when the river is very low. The review concludes:

These provisions benefit the economic interests of a few upstream users over the ecological and social needs of the many.




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What to do?

The review recommends the NSW government urgently change water-sharing rules so these better comply with the legal requirements to protect the environment and other water users, restore community trust and make the river more resilient to future shocks.

Key priorities for the NSW government are:

  • redesigning the water-sharing rules so environmental protection and basic landholder rights cannot be harmed by lesser priorities such as irrigation

  • introduce new flow targets to more effectively protect critical ecosystems and enhance river health

  • change rules relating to water extractions by A Class licence holders during critical low-flow periods, particularly those relating to commence-to-pump, cease-to-pump, and the size of pumps.

  • introduce and enforce more effective metering and monitoring

  • develop strategies and rules that address the inevitable impacts of climate change

  • develop and implement more integrated management of water resources in the northern Murray-Darling Basin.

The commission did note there have been positive changes to the NSW government’s approach to water policy and management since the ABC 4 Corners report Pumped in 2017 and the subsequent Ken Matthews report.

However, the Murray-Darling Basin Plan required NSW to complete a new water resource plan for the Barwon-Darling River by June 2019. The state missed this deadline. The NSW water minister has requested an extension to December 31 2019. A recent assessment by the Murray-Darling Basin Authority suggests NSW is still some way from completing this water resource plan.




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While NSW delays, the Barwon-Darling river system and its communities suffer. The NSW government now has an excellent blueprint for a new plan. It must urgently implement the review’s 29 recommendations and complete a new plan for the Barwon-Darling before the end of 2019.The Conversation

Barry Hart, Emeritus Professor Water Science, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Drought and climate change are driving high water prices in the Murray-Darling Basin


Neal Hughes, Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES)

Water prices in the southern Murray-Darling Basin have reached their highest levels since the worst of the Millennium drought more than a decade ago. These high water prices are causing much anxiety in the region, and have led the federal government to call on the Australian Competition and Consumer Commission to hold an inquiry into the water market.

Inevitably, whenever an important good becomes more expensive – be it housing, electricity or water – there is a rush to identify potential causes and culprits. In the past few years high water prices have been blamed on foreign investors, corporate speculators, state government water-sharing rules, new almond plantings and the Murray-Darling Basin Plan.




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While some of these factors have had an effect on the market, they are in many ways a distraction from the simpler truth: that high water prices have mostly been caused by a lack of rain.

Supply drives the market

The waters of the northern basin run to the Darling River and the waters of the southern basin run to the Murray River.
MDBA

Market reforms in the 1980s and 1990s enabled water trading in many parts of Australia. By far the most active market exists in the southern Murray-Darling basin, which covers the Murray River and its tributaries in northern Victoria, southern New South Wales and eastern South Australia.

The market allows users – mostly irrigation farmers – to trade their water allocations (effectively shares of water in the rivers’ major dams). This trading helps ensure limited water supplies go to the farmers who value them the most, which can be crucial in times of drought.

Historical data shows the main driver of water market prices in the southern basin is change in water supply.

The following chart shows storage volumes (in orange) and water prices (in red) in the southern basin since 2006. Prices peaked at the height of the Millennium drought in 2007. During the floods of 2011, they fell near zero. Prices have increased again during the latest drought, and are now at their highest levels in a decade.


Water allocation prices and storage volumes in the southern Murray-Darling Basin.
State government trade registers, BOM, Ruralco Water, ABARES estimates.

Lower rainfall, higher temperatures

While water prices have always been higher in dry years and lower in wet, we’ve been getting a lot more dry years in recent decades.

Over the past 20 years, rainfall, run-off and stream flow in the southern basin has been far less than historical conditions.

The below chart shows modelled flow data for the Murray River, assuming historical weather conditions and no water extraction, over the past century. It shows that average water flows this century are about 40% below the average of the 20th century.


Modelled ‘without-development’ annual Murray River flow, 1900 to 2018.
Murray-Darling Basin Authority.

We know these reductions are at least partly related to climate change, driven by both reduced winter rainfall and higher temperatures.

Lower rainfall and higher temperatures also make crops thirstier, increasing demand for irrigation water. This was evident in January, when temperatures exceeded 35℃ for 14 days and irrigators’ demand for water spiked from about 4.5 gigalitres to 7 gigalitres a day.




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The basin plan in perspective

The Murray-Darling Basin Plan seeks to improve the environmental health of the river system by recovering water rights from irrigation farmers. To date, more than 1,700 gigalitres of water rights – about 20% of annual water supply – have been recovered in the southern basin.

By reducing supply, water recovery was always expected to increase water prices. However, the effects of water recovery on supply – while significant – are still small relative to the effects of climate over the same period, as shown in the below chart.


Water allocation use in the southern basin with and without water recovery.
State government agencies, Department of Agriculture, ABARES estimates.

Measuring the precise effect of water recovery on prices is difficult. Water buybacks are straightforward and have been modelled by ABARES and others. But the effects of infrastructure programs – where farmers return a portion of their water rights in exchange for funding to upgrade infrastructure – are harder to estimate.




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‘Carryover’ rule changes

Historically farmers had to use water allocations within a 12-month window. The introduction of “carryover” – most recently in Victoria in 2008 – means users can now hold their unused water in dams. This rule change was a good thing, as it encourages farmers to conserve water and build up a buffer against drought.

But it might also have contributed to anxiety about the water market’s operations.

Since water allocations can be bought and held for multiple years, information about future conditions can have a big effect on prices now. For example, we see large jumps in price following news of worse-than-expected supply forecasts. This may have helped fuel concern about “speculators”.

Over the longer-term, the ability to store water helps to “smooth” water prices, with slightly higher prices in most years offset by much lower prices in drought years. Again this is a good thing, but it may have added to the perception of higher prices in the market.

Water demand is rising

When a profitable new irrigation activity is willing to pay more for water – as is the case with almond farms in the southern basin – competition for limited supplies can potentially drive up prices.

ABARES’ research shows that between 2003 and 2016 there was little change in irrigation demand (aside from that linked to rainfall). Growth in demand from expanding activities such as almonds and cotton was offset by reductions in others including dairy, rice and wine grapes. However, there is evidence since 2016 that demand for water has started to increase, contributing to higher water prices. Longer-term projections suggest this trend may continue.

With drought and climate change reducing water supply, and demand for both environmental and irrigation water increasing, high water prices are only likely to become more common in the basin in future.The Conversation

Neal Hughes, Senior Economist, Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES)

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Billions spent on Murray-Darling water infrastructure: here’s the result


Q J Wang, University of Melbourne and Avril Horne, University of Melbourne

Earlier this year, researchers suggested the amount of water returned to the Murray Darling Basin under a federal program has been “grossly exaggerated”, to the tune of hundreds of billions of litres.

The report argued that government investment in irrigation improvements might even result in a net loss of water for the environment.




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To investigate these claims, the Murray Darling Basin Authority commissioned us to undertake an independent review to examine the best available data for every irrigation efficiency project funded across the basin.

We found the government investment into irrigation efficiency projects has achieved 85% of the 750 gigalitres per year target. The remaining 15% of the target may be affected by unintended side-effects.

This result highlights the need for continued review of risks to the basin plan, as Australia grapples with the management of an extraordinary complex natural system.

How is water for the environment recovered?

The Water Act 2007 introduced significant reforms aimed at setting aside more water for the environment. At the time, record high levels of surface water were being consumed. Aiming to save 2,750 gigalitres of surface water (water flowing in the open air, rather than underground) the federal government began buying back water rights and investing in more efficient infrastructure.

The Commonwealth is providing A$3.1 billion to buy these water rights, of which A$2.5 billion has been spent. It is also providing more than A$8 billion for modernising infrastructure and water efficiency improvements, of which more than A$4 billion has so far been spent.

These projects aim to improve water delivery – reducing leaks and evaporation – and make irrigation more efficient. The water saving generated from these projects is shared between the governments for environmental use, and irrigators.

Mass fish deaths earlier in the year raised serious concerns about the health of the Murray-Darling system.
DEAN LEWINS/AAP

What are “return flows”?

To understand why the government investment in irrigation efficiency projects have not achieved 100% of the original target, we need to talk about return flows.

When water is diverted from the river for irrigation, not all of it gets consumed by the plants. Some water will make its way back to the river. This is called return flow. A large part of the return flow is through groundwater to the rivers, and this part is extremely difficult to measure. More efficient infrastructure and irrigation generally means less return flow to the river.

If these reductions are not considered when calculating the water savings, it is possible there will be implications for irrigators, the environment and other water users downstream, that previously benefited from return flows.

What we tried to determine is how much the efficiency projects reduced return flow.




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Are the water savings real?

For the first time, we attempted to bring together data on individual projects in order to assess return flows across the basin. We developed a framework for calculating return flows, which took into account water in the rivers, groundwater, and efficiency projects.

This is the first attempt to bring together the existing data on individual projects to assess return flows in the basin at a detailed level. A large portion of the data used in this study was collated for the first time and not previously available in a readily accessible format.

We found a reduction in return flow of 121 gigalitres per year as a result of the government funded projects. This is comparable to 16% of the recovery transferred to environmental entitlements.

What does this mean for the Basin Plan?

There are several important details that must be considered to assess the importance of the return flow volume for the environment and Basin Plan objectives. We do not attempt here to quantify the outcomes, but instead to raise a number of important considerations beyond simply “volume”.

1. Recovered water should be legally protected

Return flows are good for the environment, but are essentially accidental. As irrigation becomes more efficient, inevitably they will diminish.

On the other hand, formally allocated environmental water entitlements are legally protected. It is more secure for the environment – and far easier to keep track of.

2. It’s not ‘efficiency vs the environment’

Part of this debate centres around the idea that reducing return flows means less water for the environment. But in Victoria and New South Wales, before water is allocated to anyone (irrigators or the environment), a base level is set aside. This is the minimum required to keep the rivers physically flowing and to meet critical human needs.

Efficiency projects mainly affect this base-level flow of the river. This means the water reduction is shared across everyone who holds a water licence – the majority of which are irrigators.

This policy means it does not make sense to compare the effect of efficiency projects directly with the recovery of environmental water.

3. Volume is a crude measure of environmental benefit

The focus of the debate around return flows has been based on the annual volume of returned environmental water in comparison to the stated Basin Plan target.

However, the real objective of the water recovery is to achieve environmental objectives in the Basin. This is not just about annual volumes, but the quantity, timing, and quality of fresh water.

How should we move forward?

Our review has particularly highlighted the need for better ongoing data collection and regular evaluations.




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Both taxpayer investments and the water market are changing irrigation to become more efficient and reducing the river’s base flow. With this in mind, we need to regularly reexamine how we share water between everyone (and everything) that needs it, particularly in extended dry periods.

The Murray-Darling Basin is a constantly changing system, both in terms of climate and irrigation. Return flows are one of a number of potential threats to the Basin Plan. As the system is continually changing, these threats will need to be reassessed with each Basin Plan review.


A Four Corners program on the $13 billion Murray-Darling Basin Plan will air on ABC at 8.30pm on July 8.

This article was co-written by Glen Walker, a former CSIRO employee and now private consultant, who worked with the University of Melbourne on the independent review.The Conversation

Q J Wang, Professor, University of Melbourne and Avril Horne, Research fellow, Department of Infrastructure Engineering, University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Memo to the environment minister: a river does need all its water


Paul Humphries, Charles Sturt University and R. Keller Kopf, Charles Sturt University

Given her new role as federal environment minister, one of Sussan Ley’s comments in an interview with Nine Newspapers was eyebrow-raising, to put it mildly. She said:

Sometimes the environment doesn’t need all its water but farmers desperately do need water.

This is inaccurate and concerning, but not all that surprising, given the attitude to water and rivers of some in the community and federal government.

In this age of water sharing and trading, and storing water in dams, it is easy to lose sight of what water is to a river, and how every drop of water that enters (or should enter) a river defines the character and function of that river.

Ultimately, the community – not scientists or even river managers – decides how much water a river should get. But it’s essential to be honest about the effects these decisions have on rivers and the ecosystems they support. This is vital for long-term environmental sustainability, upon which all our industry, agriculture and indeed our society are based.

Crises and concerns

Recently the Murray-Darling river system has suffered several crises, including fish kills, hypoxic water, acid-sulfate soils, and algal blooms. These are all wake-up calls that the way we manage rivers are not working.




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But besides these disastrous incidents, there are many other ways in which river ecosystems are changing, that are not as obvious to the general public.

Contraction of native species’ ranges, local extinctions, success of invasive species and the “need” to stock non-native recreational fish species are just a few of the insidious symptoms of a general malaise.

Water to a river is like air to a balloon. Let out a little air and the balloon is still balloon-shaped, albeit less taut than before. But let out more air and there comes a point, which is hard to predict exactly, when the balloon suddenly collapses. By this analogy, the Murray-Darling Basin is very deflated indeed.

The point is that if we take water out of a river, or change the patterns of its flow, we inevitably change the nature of that river. Irrigators undoubtedly need water. But we shouldn’t kid ourselves that we’re not altering the river and its ecosystems by allowing them to take it.

Do we want healthy rivers?

Our job as river scientists is not to say what type of river the community wants. Our job is to inform people on what the actions of changing river management will do to a river and its life.

We already have seriously degraded river ecosystems. Restoring them is exceedingly unlikely under current demands and management. But if we take even more of a river’s water away, we need to acknowledge that the river will become yet a different river, and in some cases, one that we hardly recognise.

The public backlash following the fish kills earlier this year suggests that the community has decided that further degradation of our rivers is not acceptable.




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The Conversation


Paul Humphries, Senior lecturer in Ecology, Charles Sturt University and R. Keller Kopf, Research fellow, Charles Sturt University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

5 ways the government can clean up the Murray-Darling Basin Plan


Barry Hart, Monash University and Martin Thoms, University of New England

The health of the Murray-Darling Basin, Australia’s largest and most complex river system, is in rapid decline, and faces major challenges over the next 30 years as the climate changes.

In our view, there are still major problems with the implementation of the Murray-Darling Basin Plan. These must be addressed to make sure the system is resilient enough to have a reasonable chance of bouncing back from future shocks to the river’s ecosystems, particularly due to climate change.




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Here are five ways the government can clean up the Murray-Darling Basin Plan so the river system has a chance of surviving in the long term.

1. Allow the rivers to spill into the floodplain

There are restrictions in all states on deliberately using environmental water (water set aside to keep the rivers healthy) to go over the river bank and inundate the floodplain. When this happens, it’s known as “overbank flow”, and is restricted to areas and times of year when it’s permitted.

Overbank flow is the connection between rivers and their floodplain, and is essential for two reasons.

Populations of water birds like pelicans are not recovering as well as they used to after drought and flood cycles in the Basin.
Shutterstock

The first is to ensure floodplain wetlands and forests are resilient. For example, without additional water, the current red gum forests along the River Murray are likely to die and be replaced with black box trees, which need less water.

The second is for the exchange of nutrients and organic matter between rivers and floodplains. Without these inputs from the floodplain, the river system would only be able to support a much smaller number of fish.

Governments have been reluctant to work towards increased overbank flows, largely because of a potential backlash from landholders who don’t want their floodplain land to be flooded.




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But in several regions, such as the Edward-Wakool system in New South Wales, landowners and government officials are working through the issues that infrequent flooding has on riverside agricultural land, such as stock being unable to graze flooded areas, crops being innundated by floodwaters, and loss of access to parts of their property through road flooding.

We hope their discussions will lead to a balance, where overbank flows can still occur with minimum impact on landholders.

Still, without changes to state policies on overbank flows, parts of the Basin’s floodplain systems are unlikely to have sufficient resilience to absorb future stresses.

2. Better management of the rivers

The Commonwealth and states now have almost 3 trillion litres (3,000 gigalitres) of dedicated environmental water, purchased from irrigators, many of whom have made significant water savings by upgrading their irrigation equipment.

This is called “held” environmental water. Currently, there is around 3 trillion litres of held environmental water, and 13.7 trillion litres of water allocated to irrigators in the Murray-Darling Basin.

Management of this environmental water is relatively new, compared with the management of water for irrigators, which has been occurring for the better part of 80 years in rivers such as the Murray, Goulburn and Murrumbidgee.

There is a major difference in when environmental and irrigation water is needed through the year. Farmers have their highest water demand for irrigation in late spring and summer, while the major environmental water demand is often highest in late winter and early spring. This is when high natural inflows would have filled river channels and spilled into floodplain forests and wetlands.

The use of the river channels to deliver irrigation water has lead to large flows in the summer when naturally the river flows would have been low. This has resulted in environmental problems, such as bank erosion and the wrong triggers for fish breeding.

3. A greater focus on river refuges

During periods of low or no flow, many of the Basin’s rivers exist as networks of waterholes. In such dry periods, these waterholes are vital habitats, or “refuges”, for fish, frogs, waterbugs, and other species that need permanent water.

Changes in land use, flow regimes and the condition of riverbank vegetation all threaten the ability for these waterholes to act as refuges for these species. These waterhole refuges also need a full set of structural habitats, such as snags and riverbank vegetation.




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Maintaining a “mosaic” of refuges with different levels of connection is required for the full suite of species to be able to survive droughts.

4. Better protection of planned environmental water

Runoff – rainwater that drains from the land and into the rivers – will be seriously affected by climate change.

A predicted 20% reduction in rainfall is expected in the southern Basin by 2050. This would translate to a 40-50% reduction in runoff, and would impact on all water in the Murray-Darling Basin.

Disturbingly, the current policy in the Basin Plan safeguards the entitlements to irrigation water and held environmental water, but not the rest of the flow – which is largely also “environmental” water. Currently, this makes up around half of the total flow (32.5 trillion litres per year) in the Murray-Darling Basin a very large volume.

Drought stricken wetlands of the Murray-Darling Basin. We need a more coordinated management of all of the Basin’s natural resources.
Shutterstock

The effect varies over the basin, but by 2030, overall losses are predicted to be two to three times greater for water that is outside of these entitlements, compared with irrigation water and held environmental water.

Unless this policy is changed, climate change will have an excessive impact on the river’s health. Entitlement-holders will continue to take the same amount of water while the overall river flow drops dramatically. This deficiency must be addressed when the Basin Plan is reviewed by 2026.

5. Linking water and other natural resource management

The Basin’s water resources do not exist in isolation from other “natural capital”, such as riverbank habitats, floodplain land, and the surrounding catchments.

Before the Basin Plan, the Murray-Darling Basin Commission had in place an integrated natural resource management strategy, but this has now been discontinued.

River scientists know “the catchment rules the river”. But the water and catchments are now managed separately, despite many calls over the years for better integration.

Poor agricultural practices result in sediment, nutrients and salt entering the rivers in runoff. This reduces water quality and harms the Basin’s ability to provide essential “ecosystem services”, such as water quality improvement and the effective functioning of the ecosystem.




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We believe a more coordinated management of all natural resources in the Basin, and attention to other complementary measures, should be addressed when the current Basin Plan is reviewed in 2026.

We submit that continuing with the existing Basin Plan, it’s unlikely the Murray-Darling Basin will be resilient enough to withstand future climate impacts, and we will see major detrimental changes to the basin’s ecosystems.

At the very least, we must properly implement the current Basin Plan by addressing the first three issues above, and also make the necessary policy change to ensure the other two issues – protection of planned environmental water and better links with other natural resources – are addressed in the next Basin Plan in 2026.The Conversation

Barry Hart, Emeritus Professor Water Science, Monash University and Martin Thoms, Professor – Faculty of Humanities, Arts, Social Sciences and Education; School of Humanities, Arts, and Social Sciences , University of New England

This article is republished from The Conversation under a Creative Commons license. Read the original article.

We wrote the report for the minister on fish deaths in the lower Darling – here’s why it could happen again


Robert Vertessy, University of Melbourne; Fran Sheldon, Griffith University; Lee Baumgartner, Charles Sturt University; Nick Bond, La Trobe University, and Simon Mitrovic, University of Technology Sydney

Over the recent summer, three significant fish death events occurred in the lower Darling River near Menindee, New South Wales. Species involved included Murray Cod, Silver Perch, Golden Perch and Bony Herring, with deaths estimated to be in the range of hundreds of thousands to over a million fish. These events were a serious ecological shock to the lower Darling region.

Our report for the Minister for Agriculture and Water Resources examines the causes of these events and recommend actions to mitigate the potential for repeat events in the future.

The final report has just been released, summarising what we found and what we recommend.

Causes of the fish deaths

High-flow events in the Darling River in 2012 and 2016 filled the Menindee Lakes and offered opportunities for substantial fish breeding, further aided by the targeted use of environmental water.

The result was very large numbers of fish in the lakes, river channels and weir pools around Menindee. After the lake-filling rains of late 2016, two very dry years ensued, resulting in very low inflows into the Barwon-Darling river.

As the supply of water dried up, the river became a series of disconnected and shrinking pools. As the extremely hot and dry conditions in late 2018 took hold, the large population of fish around Menindee became concentrated within weir pools.

Hot weather, low rainfall and low flows provided ideal conditions for algal blooms and thermal stratification in the weir pools, resulting in very low oxygen concentrations within the bottom waters.

With the large fish population now isolated to the oxygenated surface waters of the pools, all that was needed for the fatal blow was a trigger for the water profile to mix. Such a trigger arrived on three separate occasions, with changes in the weather that brought sudden drops in temperature and increased wind that caused sudden turnover of the low-oxygen bottom waters.

Summary of the multiple causes of the 2018-19 fish death events in the lower Darling river.

With the fish already stressed by high temperatures, they were now unable to gain enough oxygen from the water to breathe, and a very large number of them died. As we write, the situation in the lower Darling remains dire, and there is a risk of further fish deaths if there are no significant inflows to the river.

Fish deaths caused by these sorts of turnover events are not uncommon, but the conditions outlined above made these events unusually dramatic.

So, how did such adverse conditions arise in the lower Darling river and how might we avoid their reoccurrence? We’ve examined four influencing factors: climate, water management, lake operations, and fish mobility.

Key influencing factors

We found that the fish death events in the lower Darling were preceded and affected by exceptional climatic conditions.

Inflows to the water storages in the northern Basin over 2017-18 were the second lowest for any two-year period on record. Most of the Murray-Darling Basin experienced its hottest summer on record, exemplified by the town of Bourke breaking a new heatwave record for NSW, with 21 consecutive days with a maximum temperature above 40℃.

We concluded that climate change amplified these conditions and will likely result in more severe droughts in the future.

Changes in the water access arrangements in the Barwon–Darling River, made just prior to the commencement of the Basin Plan in 2012, exacerbated the effects of the drought. These changes enhanced the ability of irrigators to access water during low flow periods, meaning fewer flow pulses make it down the river to periodically reconnect and replenish isolated waterholes that provide permanent refuge habitats for fish during drought.

We conclude that the Lake Menindee scheme had been operated according to established protocols, and was appropriately conservative given the emerging drought conditions. But low connectivity in the lower Darling resulted in poor water quality and restricted mobility for fish.

Recommended policy and management actions

Given the right mix of policy and management actions, Basin governments can significantly reduce the risks of further fish death events and promote the recovery of affected fish populations.

The Basin Plan is delivering positive environmental outcomes and more benefits will accrue once the plan is fully implemented. But more needs to be done to enhance river connectivity and protect low flows, first flushes and environmental flow releases in the Barwon-Darling river.

Drought resilience in the lower Darling can be enhanced by reconfiguring the Lake Menindee Water Savings Project, modifying the current Menindee Lakes operating rules and purchasing high security water entitlements from horticultural enterprises in the region.

In Australia, water entitlements are the rights to a share of the available water resource in any season. Irrigators get less (or no) water in dry (or extremely dry) years.

A high-security water entitlement is one with a high chance of receiving the full water allocation. In some systems, although not all, this is expected to happen 95 per cent of the time. And these high-security entitlements are the most valuable and sought after.

Fish mobility can be enhanced by removing barriers to movement and adding fish passageways.

It would be beneficial for environmental water holders to place more of their focus on sustaining fish populations through drought sequences.

The river models that governments use to plan water sharing need to be updated more regularly to accurately represent the state of Basin development, configured to run on a whole-of-basin basis, and improved to more faithfully represent low flow conditions.

There are large gaps in water quality monitoring, metering of water extractions and basic hydro-ecologic knowledge that should be filled.

Risk assessments need to be undertaken to identify likely fish death event hot spots and inform future emergency response plans.

All of these initiatives need to be complemented by more sophisticated and reliable assessments of the impacts of climate change on water security across the Basin.

Governments must accelerate action

Responding to the lower Darling fish deaths in a prompt and substantial manner provides governments an opportunity to redress some of the broader concerns around the management of the Basin.

To do so, Basin governments must increase their political, bureaucratic and budgetary support for high value reforms and programs, particularly in the northern Basin.

All of our recommendations can be implemented within the current macro-settings of the Basin Plan and do not require a revisiting of the challenging socio-political process required to define Sustainable Diversion Limits (SDLs).

Successful implementation will require a commitment to authentic collaboration between governments, traditional owners, local communities, and sustained input from the science community.


The authors would like to acknowledge the contribution of Daren Barma, Director of Barma Water Consulting, to this article.

A version of this article has been published in Pursuit.The Conversation

Robert Vertessy, Enterprise Professor, University of Melbourne; Fran Sheldon, Professor, Australian Rivers Institute, Griffith University, Griffith University; Lee Baumgartner, Associate Research Professor (Fisheries and River Management), Institute for Land, Water, and Society, Charles Sturt University; Nick Bond, Professor of Freshwater Ecology and Director of the Centre for Freshwater Ecosystems, La Trobe University, and Simon Mitrovic, Associate Professor, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.