Calls are growing stronger for more attention to be paid to the Upper Murrumbidgee River. Photo: The Australian River Restoration Centre.
The Upper Murrumbidgee “will likely die” if the amount of water released from Tantangara Dam doesn’t dramatically increase.
That’s the advice from an independent review panel which has looked at the deed under which this water management sits.
The panel found that the Snowy Water Inquiry Outcomes Implementation Deed (SWIOID, also known as the deed), established in 2002 to increase the volume of water flowing from the Snowy Scheme to montane rivers, originally released more water.
But the flows were “manifestly inadequate in volume and timing” to ensure the rivers and catchments remained healthy.
“The poor state of the Upper Murrumbidgee River at times provides a risk to water security and human health,” its draft report stated.
“Should governments decide not to proceed with this package of reforms, the Upper Murrumbidgee will likely die, with its flora and fauna irreversibly lost. Downstream communities will also suffer.”
The Murrumbidgee River flows through the length of the ACT, but the ACT Government isn’t part of the deed. One central recommendation is to rectify this so that the ACT can be at the table with NSW, Victoria and the Commonwealth.
The governments then need to “act expeditiously” on the review’s recommendations.
“A decision not to implement this package of reforms will save money (at least in the short term), avoid putting into practice a raft of new initiatives and programs which will involve challenging coordination of funding, people and activity and inconvenience for Snowy Hydro,” the panel stated.
“However, such a decision will effectively condemn the Upper Murrumbidgee to a gradual death.”
The current deed specifies an average annual environmental flow target of 27 gigalitres (GL), but between 2008 and 2025, the average annual release was only about 21.2 GL.
It has resulted in poor condition of native fish populations (particularly the endangered Macquarie Perch), localised species extinction, degraded habitat quality, prolonged low-flow periods, elevated temperatures, and concentrations of blue-green algae and faecal indicator bacteria exceeding human health guidelines.
“Climate change forecasts mean these challenges will be amplified,” the draft report stated.
“Without changes … the Upper Murrumbidgee will remain degraded with an increasing risk of irreversible ecological decline.”
The panel’s called for environmental flows in the Upper Murrumbidgee River to be increased to an average annual target of 30 per cent (87 GL equivalent) of Tantangara Dam’s average annual flows.
This should occur through a staged release, commencing with an increase to an average annual target of 23 per cent (68 GL equivalent) of average annual inflow.
The Upper Murrumbidgee River dried to pools upstream of Tharwa Bridge in December 2019 (pictured) and again in 2025. Photo: Simon Lowes.
Of the five options put forward, the panel recommended that option 5 (a near-term, climate-responsive approach with 22.8 per cent of ‘natural flow’ returned without development) be implemented immediately, while work starts on option 4 (system-scale recovery with higher releases from Tantangara Dam).
“Option 4 requires upgrades to Tantangara Dam to deliver channel maintenance flows and the Panel has recommended that a feasibility report and costing be developed to assess this in more detail,” the draft report stated.
“Option 5 should be progressed in the interim as this offers the strongest benefit-cost ratio, particularly given the advantages associated with channel clearing flows.
“These recommendations are essential to support species persistence, maintain water quality, protect human health, and secure critical human water needs, at the same time as supporting the national energy market.”
The panel found that making such changes would have very minor impacts on energy production through the Snowy Hydro scheme and on the electricity network.
It also recommended that the Mowamba Weir be decommissioned so that the Mowamba River can act as a natural headwater for the Snowy River and increase natural flow variability.
The Upper Murrumbidgee has long been called the ‘forgotten river’, so news of recommendations directly targeting its health has been welcomed in environmental spaces.
Conservation Council ACT Region executive director Simon Copeland said the recommendation to increase environmental releases to the equivalent of 30 per cent of annual natural flows was particularly vital.
“It is critical that this 87GL/yr (30 per cent) target is mandated and that there is ongoing monitoring, compliance and reporting to ensure it is delivered,” he said.
“We need to make sure we don’t repeat the mistakes of the current system, where the target is a maximum volume, and the system was designed so that not enough water was available to meet the target each year.
“The river cannot wait too long for the water that it needs. We encourage governments to set a firm deadline for completing flow trials and any further investigations, and shifting to full implementation of the 30 per cent target.”
The ACT Government is considering the report before making any comment on the recommendations.
But a spokesperson said it would continue to advocate for solutions that support the long-term health of the Upper Murrumbidgee River while protecting water security.
“Our focus remains on achieving the best long-term environmental, cultural, and community outcomes for the Upper Murrumbidgee River system, while ensuring sustainable water management outcomes for the ACT,” they said.
In 2024, the ACT received $7.58 million (over five years) to deliver the Restoring the Upper Murrumbidgee River program with projects underway in the Naas and Gudgenby catchments.
