RIVER YARNS: THE MURRAY-DARLING MYTHS: WEEK FIVE
Talking about River Yarns
With assistance from the Walkley Foundation, McPherson Media Group has commissioned Jane Ryan, a consultant with long experience and deep knowledge of water and resource management in the Murray-Darling Basin, to unravel the complex issues surrounding the Murray-Darling Basin Plan.
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Jane’s brief is to do so without the bias and hyperbole that has accompanied most commentary on the plan since its inception 14 years ago.
At a time when the Federal Government seeks to amend the plan to give effect to election promises to South Australia, Jane’s analysis will canvas what the plan has achieved already in the long history of resource management in the basin.
She explores the shortcomings of a political compromise on ‘a number’ for water recovery, when what is really required is a nuanced approach to securing the original ambitions for the plan.
In this fifth article in the series, Jane describes how catchment managers balance up how and where to focus their efforts to improve the ecological condition of our water landscapes.
OUR WORKING RIVERS
There are different environmental, economic, social and cultural values that communities expect to be managed.
It gets harder if we’re not clear about the existing condition and how that influences what it’s possible to do, what we need to focus on and what success looks like now and in the future.
We’ll firstly look at the concept of a working river and the value of acknowledging the current situation within the southern-connected systems in the Murray-Darling Basin.
After that, we’ll look at what thriving ecosystems mean in this complicated picture and the most challenging aspects of change.
As we’ve said in earlier River Yarns, waterways have always been the most attractive features of the catchment to live, love and play beside.
The First Nations people living along rivers had sophisticated customs and protocols that helped their communities thrive in the dry and wet cycles of River Country. There is a history of changes to the landscape that these communities made, including working with fire, using natural features to farm fish and channelling water to where medicinal and fibre plants could grow.
Since then, there have been big changes to the landscape with the growth of people making their homes in River Country.
The process of shaping waterways to service humans started in the Murray-Darling Basin in the 1800s, and initially infrastructure helped communities to manage through intermittent flows and floodwaters.
Water was pooled so that in dry times, water was still in ponds for water supply, aesthetic purposes and even to mitigate risk of waterborne diseases. In wetter times, levees regulated the spread of water into houses and townships and protected crops.
Did you know the Murray and Goulburn rivers have more than 15 locks, three major dams and six barrages?
There are very few waterways in Victoria that don’t have some form of infrastructure changing the flow of water that runs in the channel or across floodplains.
Big waterways that flow into the Murray, such as the Goulburn, all have dams and weirs, as well as bridges, roads and the culverts that are placed where they cross over waterways.
Dams and weirs store water, whereas culverts for roads and bridges disconnect them depending on where they are, and their size.
Smaller waterways – such as the Campaspe, Kiewa or Broken rivers – also have infrastructure, some of which can cut off the upper from the lower parts, affecting the spawning and growth of large-bodied fish.
The existence of three of Australia’s five biggest dams in this part of the basin means that the largest rivers in the southern-connected systems are effectively hard-working rivers. They supply water and other essential services to communities in some of the biggest towns identified in previous River Yarns.
When catchment managers talk about the impact of regulation on the ecological condition of the landscapes they are managing, they are talking about the dams, locks and barrages that now control the way water flows.
When they talk about regulation impacts, they don’t just talk about the volume of water in the system – which if you had been following the debate around the now-passed legislation, you would think was all that mattered.
Some of the biggest impacts that science is rushing to document focus on the change in timing of flows caused by these massive dams.
They are incredibly effective at storing much of upper catchment flows and rainfall, so they no longer flow down the river unrestrained.
These dams were built to store, not release, big volumes of water.
Did you know there have been changes in flow from 1836 when the first weir was built?
Our working rivers in the southern-connected basin are controlled within an inch of their lives, with services provided to urban and rural communities living in the catchment as the trade-off.
Weirs act like mini storages, causing water to bank up behind them rather than letting it flow downstream. The smallest ones allow water to flow as a spill where the land pushes the water back into flowing down the waterway.
Big regulating infrastructure like the weirs, locks and barrages on the Murray River use large gates requiring releases of water, as well as operational protocols and rules or decisions made to deliver water to downstream users.
Very little unregulated water flows down our rivers these days, because all flows past weirs are releases of water, just like releases out of big dams.
The Murray River is more controlled than Melbourne’s Thomson Dam, for instance – yet people aren’t calling for more than three quarters of the flow to be given back to improve the health of rivers around Melbourne!
They recognise that waterways in Melbourne’s catchments are working rivers and that a balance of water values and services needs to be achieved.
The first weir installed in the Murray River was the model for how the natural flows would be changed.
We have all seen the picture of the picnic on the bed of the river in Koondrook back in the 1800s with little or no flow in the Murray. We also know that First Nations communities all along the Murray knew where water could still be found even in dry times, and they gathered around these places.
We now call these times ‘cease to flow’ events when we’re thinking about what plants and animals need to thrive in these landscapes.
Our big rivers like the Goulburn and the Murray don’t have these extremes at all anymore.
In the hydrograph from Weir 1, near the South Australian border, we can see the dramatic ups and downs of flow – years without flow at times, and other times years of higher flows for much longer than we ever have now.
Did you know that most of the water flowing down our big rivers has to be let out of dams?
I think it’s important to understand how dramatically altered our big, regulated working rivers really are and how difficult it is to get environmental outcomes from simply returning conditions to ‘natural’.
Despite the documents written as the original Guide to the Basin Plan back in 2012 suggesting the Murray-Darling Basin Authority had modelled that the environment needed a flow of five to seven gigalitres to be healthy, we now know that those figures were exactly two-thirds of all flow down the river. This suggests those figures were more about maths than science.
The idea that it would produce a healthy basin if we could get two-thirds of previous flows going down our rivers – only to be used for the environment – is strange to me.
It denies all the catchment impacts on waterways, such as land clearing and disconnection of smaller waterways, floodplains and wetlands from ever-expanding urban and agricultural landscapes.
Nor does it deal with the elephant in the room: big infrastructure is the way most of our water flows – except for some unregulated flow from some small waterways when rainfall occurs below storages (the recent heavy falls below Eildon around Tallarook are an example).
Do we ever hear anyone asking to get rid of Eildon, Hume or Dartmouth dams?
Because if we accept these big dams aren’t going anywhere, most flow now comes spillways and gates that release water set by a complex set of rules and protocols.
Much of the environmental water is provided by rules that operate this infrastructure, such as those guiding a minimum volume released regularly (particularly important in the dry) or spill rules if the dams are full and extra rain or flows are coming.
When water is held by an environmental water holder, water in dams is ordered to be delivered and will be part of those rules and protocols guiding the release.
The idea that buying more water will automatically reinstate ecological functioning and provide all the environmental outcomes we’re looking for is simply unrealistic.
Like most cumulative and integrated problems that have been developed over a long time, modified catchments such as the Murray-Darling Basin need modified solutions.
Why don’t people want to take out our big dams?
We now know that a dam is the greatest impact you can have on waterway health, and this is part of the reason we don’t build them anymore.
We already have built enough dams to support communities with healthy, clean drinking water for use in our homes, businesses and hospitals. We have a basic understanding of hydrology and know that storing water in one place takes it from another. And we have chosen some places in the upper catchment that help us to share it out to many communities along our working rivers, like the Goulburn and the Murray.
And before people want to tell me about the behaviour of floodwaters showing that not all is stored in storages – I agree, ‘nature’ does its best to prove we are not the boss of it!
However, if you look closely, infrastructure still holds up and stores water even during flood events.
Downstream communities bravely facing floodwaters coming down the river want to hear that the dams and weirs are holding back some of what would naturally be coming down the river. But this is true, nonetheless.
THE REALITY OF OUR RIVERS
So, I hope this River Yarn paints a clearer picture about the reality of changed catchments and working rivers that we face as we work to improve the condition of river landscapes.
Communities living in catchments, floodplains and along rivers – I’m looking at all Victorians and many Australians here – have to acknowledge the condition of our environments, as we act to improve it.
Catchment managers follow the precautionary principle of doing no further harm, but also acknowledge that active management is vital in rehabilitating modified systems. Setting and forgetting will never work here.
Despite catchment science telling us that these are medium to long-term trends we’re after, sensational claims from advocates tell us we should have seen change already.
We have seen some changes, but they are not at the landscape-scale, nor even an ecological community-scale. That is close to impossible, so we need to talk about what is possible.
NEXT: Jane will explore the changes that have been made in the Murray-Darling Basin.
About the author
Jane Ryan — a former school captain at Notre Dame College in Shepparton — was deputy chief of staff to former Victorian Water Minister Lisa Neville, and has worked in senior roles in water resources and catchment management, including Director of Rural Water Policy and Programs, Strategic Engagement Manager for River Health and Consultation Manager for the Northern Region Sustainable Water Strategy.
During the millennium drought, Jane was involved in the development of the key water policies that remain the cornerstone of water management in northern Victoria, including environmental water recovery targets, carryover arrangements and changes to allocation water policy for the Goulburn and Murray systems in response to climate change.