The Menindee Lakes are a chain of seven natural shallow lakes located near the town of Menindee in western NSW. There are four main lakes in the system and historically, due to the flat terrain and hot, dry climate, the lakes  often naturally dry up. The NSW Government have modified the lakes (completed 1968) to improve their storage capacity for farming, recreation, mining and urban water supply and to help manage floods in the Darling River.

The significant rainfall events which occurred between mid to late March across much of northern and central NSW have resulted in high flows and even flooding for tributaries feeding into the Darling River. As a result, the Darling River has slowly moved these high inflows down river to reach the Menindee Lakes more than a month later.

WaterNSW forecasts 800 – 1,000 gigalitres (GL) of water to reach the Menindee Lakes from this event which will lift the lakes from holding 300GL, at the end of March 2021, to their highest level in over four years. It is difficult to forecast the amount with more precision as downstream losses are forecast to be in the order of 500 GL from wetting up the floodplain and billabongs.

The Menindee Lakes so far have reached 940GL which is close to 55% full. On 7 May the storage level exceeded 640GL and that is the threshold for operational management to transfer from WaterNSW to the Murray-Darling Basin Authority (MDBA) on behalf of the three Murray states NSW, VIC and SA) to support Murray entitlement allocations as well as managing competing environmental and community objectives.