Rising river alert – Upper Murrumbidgee River below Tantangara Dam

The NSW Department of Climate Change, Energy, the Environment and Water today issued a ‘rising river alert’ for the upper Murrumbidgee River below Tantangara Dam in southern NSW for Thursday 25 September 2025, because of a planned high-flow environmental water release.

The highest flow rate for this event will occur at Tantangara Dam from midday on Thursday 25 September and will be equivalent to 1,500 megalitres per day for the 24-hour period through to midday Friday 26 September.

It is expected that the river level at Yaouk will rise by approximately 0.5 m as a result of the environmental flow.

From midday on Friday 26 September, the flow rate will drop back to a target of about 475 megalitres per day.

The impact on water levels from this release are expected to be greatest between the dam wall and Yaouk. However, the flow pulse will be noticeable further downstream. Natural tributary inflows will also contribute to water levels as the flow pulse moves down the river.

Water released from Tantangara Dam may take about 12 hours to reach Yaouk at this flow rate and around 2.5 days for the flow to arrive at the ACT border, subject to catchment conditions.

Landholders downstream of Tantangara Dam are advised to take all necessary precautions with stock, fencing and property in proximity to the river. As the release flows through the system people should refrain from entering or crossing swollen waterways.

Conditions will be closely monitored in the lead up to the release. Planned flows may be modified or cancelled subject to climatic, environmental or operational conditions nearer to the time of release.

We will work closely with the NSW State Emergency Service and the Bureau of Meteorology to provide information to the community regarding the management of this release if required.

More information can be found at: Snowy Montane Rivers Increased Flows | NSW Government Water.