Governments Deliver Over 37 Gigalitres of Environmental Water to Barwon–Darling River

The Commonwealth and New South Wales governments delivered more than 37 gigalitres of environmental water to the Barwon–Darling river system between December 2025 and March 2026 to counter severe dry conditions.

The coordinated watering action was initiated after drying conditions began across the northern Murray–Darling Basin in October 2025. River flows dropped rapidly, raising the risk of blue-green algae and disconnected waterholes, with the Barwon River ceasing to flow at Mungindi twice—once in late December and again in early January.

To address the drying riverbed, three regulated environmental water releases totaling 37.14 gigalitres (GL) were made from Glenlyon Dam in the Border Rivers system and Copeton Dam in the Gwydir system. The releases included 4.96 GL from the Border Rivers and 32.18 GL from the Gwydir system via the Mehi River and Carole-Gil Gil Creek, comprising 26.68 GL from the Commonwealth and 5.5 GL from NSW.

Water released on December 24 traveled nearly 2,000 kilometers downstream, reaching Wilcannia 48 days later. According to government data, approximately 13.6 GL reached Wilcannia, and 8.8 GL was protected through to Menindee Lakes, with some water lost along the way to evaporation and seepage. The flow also maintained a target baseflow of 280 megalitres per day at Collarenebri between January and March.

Officials reported that the water deliveries improved dissolved oxygen levels, lowered the risk of algal blooms and fish deaths, and reconnected refuge pools for native fish movement and spawning. Field observations also noted increased waterbird activity along the corridor.

The operation was supported by members of the Northern Basin Environmental Watering Group, including WaterNSW, NSW Fisheries, the Murray-Darling Basin Authority, and relevant state and federal departments. Authorities stated that outcomes from the summer delivery will help inform future watering operations across the northern Murray–Darling Basin.

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