Lower Darling

Lower Darling
Drought Stage

Stage 1 - Normal management

Stage 1 normal operations - de-escalated from Stage 4 critical on 23 March 2020, from Stage 3 severe on 1 May 2020 and from Stage 2 recovering on 15 April 2021.

Storage Level
  • Menindee Lakes is at 19% (329 GL) compared to just 1% full (16 GL) on 1 July 2019, but down from 27% in July 2020. However further inflows are arriving at the lakes which are expected to reach 640 GL in May.
Allocations
  • 30% general security allocations announced on 1 July 2020 and full town, domestic and stock and high security allocations. This was increased to 1005 general security allocations on 15 April 2021.
  • Zero general security allocations for most of 2019/20 until 30% announced on 1 May 2020.
  • All carryover suspended until restrictions lifted on 30 March 2020.
  • Last previous general security allocation (prior to May 2020) made in 1 July 2017.
  • Reduced allocations announced for high priority (town, domestic and stock) and high security (permanent plantings) needs were announced on 1 July 2019. These were increased to full (100%) allocations on 1 April 2020.
Actions
  • Rainfall and restrictions on access to river and overland flows across the entire Northern Basin from February to end of March 2020 resulted in over 670 GL entering Menindee Lakes by the of June 2020 - the flows began arriving from 10 March and were the first substantial natural inflows into the Lakes for three years. Flows from this event were completed by June.
  • Temporary water restriction was put in place on 4 December 2018 in the Lower Darling limiting water extraction to high priority needs - only lifted on 30 March 2020.
  • Four block banks were constructed in river in 2018 to pool water for stock and permanent plantings. These were removed in March 2020 to allow releases from the Lakes to flow along the length of the Lower Darling. The release commenced on 26 March 2020 and flows reached the junction with the Murray River around 21 April 2020. The size and timing of the release was designed to minimise the impacts on water quality and fish.
  • Following the return to normal minimum releases of 200-350 ML/day as required under the water sharing plan, additional water by the environmental water holder was released from September 2020 to mid-January 2021 to increase flows to stimulate fish breeding and recovery.
  • Pipeline from Murray River to supply Broken Hill began operation in April 2019.
  • Water carting was provided for domestic water for some landholders not connected to town supplies 2019/20 and 2020/21. A rebate of $2,000 was also provided to landholders in 2020 who normally accessed domestic water from the river.
  • DPI Fisheries installed aerators at four locations and three were installed by OzFish and local community in 2019/20. These were removed as the Lower Darling releases progressed down the river.
  • In September 2019, 783 large adult fish were relocated to more permanent water.
  • Valley based technical groups, including government and community representatives, established in the Lower Darling to advise on strategic interventions and priority actions for fish management, including the size and timing of releases from Menindee Lakes from late March.
Issues
  • Between December 2018 and January 2019 there were three incidences of massive fish deaths (estimated at over 1 million fish) in the  Lower Darling. These were the result of not enough flow in the river, poor water quality, and high temperatures followed by a sudden drop in temperatures which caused hypoxic (low oxygen) levels in the refuge pools.
  • Small number of deaths in November 2019 and at Wentworth in January 2020.
  • Fish deaths occurred around 12 March 2020 as a result of the poor quality of water at the front of the flow entering Lake Wetherell. Water quality improved as more water entered the lakes.
  • No fish deaths occurred as a result of the managed re-start release from the Lakes into the Lower Darling in late March 2020.
  • The front of the inflows into Menindee Lakes has low dissolved oxygen levels.  These inflows will be managed to try to mix this water with the better quality water in the top Lakes or divert it into Lake Menindee to help mitigate the risk to fish and other aquatic species.  Once the initial flows arrive, the water behind is generally of better quality.
Outlook
  • Normal regulated river operations re-commenced in April 2020, with all block banks removed and enough resource available to supply landholders and maintain connectivity to the Murray until at least April 2022.
  • Some 450 to 650 GL of inflows are expected from high flows in March 2021 across the northern valleys and Queensland into the Barwon-Darling resulting in announcement of 100% general security allocations.
  • Full (100%) allocation can also be expected for towns, domestic and stock access licences, and high security entitlements in 2020/21.