Rainfall and flows

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.

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.