A NSW Government website

North-west flows in early 2020

Rainfall and flows

Learn about the rain that caused substantial flows in the North-west.

Darling river in outback Australia near the town of Bourke.

Rainfall created substantial flows

From late January rain fell across parts of north-west New South Wales and southern Queensland. Over the weekend of 8th and 9th of February severe storms caused localised flooding in the Namoi and Gwydir valleys, particularly on the floodplain. Rainfall continued in various parts of the Northern Basin in February, March, April and May. This rainfall created substantial flows in the Border Rivers, Peel, Namoi, Gwydir and Macquarie valleys and along the Barwon-Darling River.

Murray-Darling Rainfall totals (mm) 1 January to 31 March 2020
Source: ©Commonwealth of Australia 2020, Bureau of Meteorology. Reproduced in accordance with the Creative Commons Attribution Australia Licence. The map has not been modified.

Before these rains created flows, some major river systems had ceased to flow for extended periods. These river systems include the:

  • Macintyre River below Boggabilla
  • Mehi and Carole Rivers in the Gwydir
  • Namoi River below Keepit Dam
  • Peel River below Dungowan
  • Macquarie River below Warren
  • Barwon-Darling system, and
  • Lower Darling River below Menindee Lakes

Rain created flows that recommenced and connected the northern tributaries with the Barwon-Darling River. By the 20th of February, the initial target flows of 60-70 GL were forecast to reach the Menindee Lakes. With further substantial rain and inflows in Queensland, the Barwon Darling River, and the Macquarie River, the volume forecast to reach the Menindee Lakes became 205-250 GL. From 10th March, the Barwon-Darling River was flowing along its full length from Mungindi on the Queensland border, into the Menindee Lakes. Thousands of kilometres of rivers flowed for the first time in many months. Substantial additional rain fell in late March and April, creating flows of 480 GL at Brewarrina. This was followed by May rainfall of 40-50 mm across central NSW. By the end of June, the Menindee Lakes had received more than 583 GL of total inflows.

Northern Basin flows - 1 January 2020 to 19 April 2020
The map above shows the end of system and key gauge flows for the period from 1st February 2020 to 28th April 2020.

Releases from the Menindee Lakes to re-start flows in the Lower Darling River commenced on the 26th of March and reached the Murray River in mid-April 2020. Water was initially released from the Menindee Lakes at a high rate to manage any potential water quality impacts of restarting the river, and to help the movement of fish populations previously stranded in refuge pools. Lower, base flow releases are now following the first pulse flow, and these will continue, maintaining supply to Lower Darling landholders for the next 12 to 18 months.

Replenishment of town water supplies

Many towns benefited from these flows. Water supplies were secured, and all town weir pools filled for Goondiwindi (population 5,500), Boggabilla (550), Mungindi (600), Collarenebri (650), Walgett (1,530) Brewarrina (930), Bourke (2,100), Wilcannia (610), Menindee and Sunset Strip (450) and Pooncarie (80).