From time to time I am told that the river system of the Murray–Darling Basin is best left to itself, without our help, because our environment is robust and will always bounce back.
Indeed the basin’s environment is resilient—it has evolved to thrive through the extremes of drought and flood.
The Murray–Darling, however, is a working river system. For more than a hundred years it has been progressively geared to deliver water as a resource for farming, for mining, for towns and other parts of our economy.
As a consequence we have shaped the environment that we have today, which means the resilience of the river system depends in large part on the deliberative steps we choose to take, to protect it, to manage it, and to benefit from it.
That’s what the Basin Plan is all about—ensuring the environment gets its fair share of water and in ways that provide the greatest value possible, while also ensuring the needs of established communities and industries are met.
Last year the MDBA’s evaluation of the Basin Plan found that returning water to the environment is starting to make a real difference. An assessment of data over 10 years at the six Murray icon sites also showed clear improvements.
Water delivered through the Barmah–Millewa Forest last year, for example, assisted the growth of threatened Moira grass and helped to trigger a breeding event for 11 species of water birds. At Hattah Lakes, water pumped from the Murray River enabled flows to reach blackbox trees that had not received water since 1993 and populations of the endangered regent parrot are recovering. Managed flows over several years in the Murray and its tributaries have been supporting the migration and breeding of populations of native fish such as the endangered Murray cod and golden perch.
There’s still a long way to go to restore the system to health, but these signs of renewal indicate that we are on the right track.
Water alone is not enough
The evidence from the Murray icon sites shows that water alone is not enough to achieve environmental change of the magnitude needed to secure the future health of the Basin system. To deliver for the environment, we need changes to river operation rules so we can operate the river differently, for example by facilitating larger pulsing flows in late winter and spring. We also need to embrace new ways of working, taking on disciplines such as engineering to ensure we can get environmental water to where it’s needed, at the right time and in the right volume, to build resilience in dry times and boost the benefits of natural flooding.
Structures such as regulators and levees enable water managers to inundate areas of the River Murray floodplain and keep water in the wetlands and billabongs in ways that would only have happened during large natural floods—events that are much less frequent since dams and weirs were built to support communities and agriculture.
Works and measures of this kind amount to smarter and more collaborative ways of managing our water resources for everyone’s benefit, and have been put forward by the South Australian, Victorian and New South Wales governments as part of the Sustainable Diversion Limit Adjustment Mechanism.
Some projects are already completed and successfully operating. Other projects are at the feasibility stage and require community input to be fully developed. Once they are all up and running, the ecological targets established in the Basin Plan will continue to be met, including those at the very end of the system in the Coorong, Lower Lakes and Murray Mouth, where explicit indicators keep a measure of flows and salinity levels.
The MDBA will continue to assess the projects during implementation to ensure desired outcomes are achieved by June 2024, otherwise water will still need to be recovered. As a package, environmental outcomes equivalent to 605 gigalitres must be achieved.
At the same time, the Basin Plan also requires a commitment from Basin governments to increase the amount of water for the environment by 450 gigalitres. To deliver this water back into the rivers by 2024, all governments need to commit to further water saving infrastructure on- and off-farm in ways that have neutral or positive social and economic outcomes.
The task of proactively managing water for the environment is challenging and rewarding. As we learn, we are truly embracing the concept of adaptive management.
There are plenty of examples of the environment bouncing back with the help of targeted watering. These before and after images show what happened recently at Reedy Lagoon in Victoria, when low water levels were dropped further to remove carp, followed by environmental watering that resulted in an abundance of vulnerable river swamp wallaby grass. North Central CMA released this video about the event. (courtesy NCCMA)
Judgement based on scientific rigour
More than any other part of our nation, the Murray–Darling Basin represents a complexity of natural systems, communities, industries and jurisdictions—threaded together by our longest rivers and all reliant on the Basin’s water resources.
The success of measures outlined in the Basin Plan relies on hard work and collaboration by all Basin governments, communities and the MDBA. The MDBA’s job is to gather the science, conduct the research, refine the modelling and engineering, and understand the needs of the people and environments of the Basin.
Importantly, the MDBA’s modelling assumes compliance by water users and governments, coordination of tributary flows and protection of environmental flows.
The Basin Plan is a huge reform. It is the fundamental re-balancing of the share of water between communities, industries and the environment, across state boundaries. It allows a Basin-wide approach to environmental watering, rather than a site or catchment scale approach.
With plenty of opportunities for future review, the Basin Plan is our best option for protecting the future of Australia’s most important water resource, and the environments, communities and industries that rely on it.
Author: Carl Binning, MDBA Executive Director Partnerships