In early 2018, dry conditions prevailed across the northern Murray–Darling Basin placing significant stress on the Barwon–Darling river system. As the dry continued, extensive reaches of the Barwon and Darling rivers, downstream of Brewarrina, ceased to flow. By March, northern tributary flows were in decline.
To support the health of the Barwon and Darling rivers, the Gwydir Environmental Water Advisory Group endorsed the release of water from held Gwydir environmental water accounts.
This joint effort by the NSW and Australian Governments saw water released from held environmental water accounts into the rivers of the northern basin from mid-April to June, which provided a much-needed drink to the Barwon–Darling rivers.
The flow aimed to:
- connect river systems
- improve water quality
- provide habitat and food sources for native fish populations.
The flow began with a release of 4300 megalitres of Commonwealth Environmental Water Office (CEWO)-owned water from the Border Rivers catchment in mid-April. This water was held in Glenlyon Dam, the headwaters of the Dumaresq and Macintyre river systems.
In early May, the Gwydir catchment contributed 18,900 megalitres to the Northern Basin Connection Flow, delivered via the Mehi River and Carole Creek. New South Wales contributed 6600 megalitres and CEWO 12,300 megalitres from general and high security accounts in the upstream Copeton Dam, on the Gwydir River.
This delivery of water for the environment:
- replenished refuge sites supporting native fish and other wildlife
- released essential nutrients to invigorate the aquatic food web and feed native wildlife including Murray cod, golden perch, crustaceans, insects and more
- supported several protected native fish including species listed under NSW and Commonwealth legislation, and the IUCN convention
- benefited wetland plants both instream and on the river bank.
Photo: The Gwydir River at Bingara. Daryl Albertson/OEH